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A review of selected dental literature on contemporary provisional fixedprosthodontic treatment: Report of the Committee on Research in FixedProsthodontics of the Academy of Fixed Prosthodontics

David R. Burns, DMD,a David A. Beck, DDS,b and Steven K. Nelson, DMDc

School of Dentistry, Virginia Commonwealth University, Richmond, Va; School of Dentistry,Medical College of Georgia, Augusta, Ga

One goal of the American Academy of Fixed Prosthodontics is regularly to publish comprehensive lit-erature reviews on selected topics germane to the discipline of fixed prosthodontics. The following re-port is the result of this goal and focuses on provisional fixed prosthodontic treatment. Major subtop-ics include materials science and clinical considerations involving natural teeth and dental implants.The interrelationship between provisional and definitive fixed prosthodontic treatment is multifacetedand significant. Provisional therapy involves numerous materials and techniques that require specialknowledge and technical experience. In this analysis, technical, clinical, and investigational articles aredetailed and presented as a comprehensive literature review to provide contemporary guidelines. Refer-enced publications were found by conducting a Medline search and were limited to peer-reviewed, En-glish-language articles published from 1970 to the present. Materials used with provisional treatmentare discussed in terms of clinical selection and the influence of their physical properties on treatmentoutcome. Specific product names and manufacturers are included in this report only when they arecited in the original referenced publications. (J Prosthet Dent 2003;90:474-97.)

Fixed prosthodontic treatment, whether involvingcomplete or partial coverage and natural tooth or dentalimplant abutments, commonly relies on indirect fabri-cation of definitive prostheses in the dental laboratory.Historically, the necessity for provisional treatment hasbeen primarily derived from this methodologic process.The importance of interim treatment, however, is morefar-reaching than is portrayed by this procedural neces-sity, and the requirements for satisfactory provisionalrestorations differ only slightly from the definitive treat-ment they precede.1 Vahidi2 and others3-7 identifiedmultiple areas of critical concern with provisional resto-rations including esthetics, comfort, speech and func-tion, periodontal health, maxillomandibular relation-ships, and continued evaluation of the fixedprosthodontic treatment plan. Biologically acceptablefixed prosthodontic treatment demands that preparedteeth be protected and stabilized with provisional resto-rations that resemble the form and function of theplanned definitive treatment.8 They can assist in themaintenance of periodontal health2 and promoteguided tissue healing by providing a matrix for sur-rounding gingival tissues.9 This is especially useful withtreatment involving highly esthetic areas. The rationalefor provisional treatment is shown in Table I.5,10

Besides the immediate protective, functional, and sta-bilizing value, interim restorations are useful for diag-nostic purposes where the functional, occlusal, and es-

thetic parameters are developed to identify an optimumtreatment outcome before the completion of definitiveprocedures.9,11 A provisional fixed restoration will pro-vide a template for defining tooth contour, esthetics,proximal contacts and occlusion,12 and for evaluatingthe potential consequences from an alteration in thevertical dimension of occlusion.2 Provisional treatmentcan also provide an important tool for the psychologicalmanagement of patients where a mutual understanding

aProfessor, Department of Prosthodontics.bAssociate Professor, Department of Prosthodontics.cAssociate Professor, Department of Oral Rehabilitation, Medical

College of Georgia, School of Dentistry.

Table I. Rationale for provisional treatment

Protect pulpal tissue and sedate prepared abutmentsProtect teeth from dental cariesProvide comfort and functionEvaluate parallelism of abutmentsProvide method for immediately replacing missing teethPrevent migration of abutmentsImprove estheticsProvide an environment conductive to periodontal healthEvaluate and reinforce the patients oral home careAssist with periodontal therapy by providing visibility and access

to surgical sites when removedProvide a matrix for the retention of periodontal surgical dressingsStabilize mobile teeth during periodontal therapy and evaluationProvide anchorage for orthodontic brackets during tooth

movementAid in developing and evaluating an occlusal scheme before

definitive treatmentAllow evaluation of vertical dimension, phonetics, and masticatory

functionAssist in determining the prognosis of questionable abutments

during prosthodontic treatment planning

Modified from Federick5 and Krug.10

474 THE JOURNAL OF PROSTHETIC DENTISTRY VOLUME 90 NUMBER 5

of treatment outcome and limitations of treatment canbe identified.12

The use of provisional restorations relies on a reason-able turnaround time from tooth preparation to com-pletion of definitive treatment. Provisional treatment isusually well tolerated when this occurs. Longer timeperiods of use can promote tooth sensitivity and poten-tial pulp damage.13 Occasionally, however, interimtreatment has to function for extended intervals andprovide long-term tooth protection and stability whileadjunctive treatment is accomplished.14,15 These proce-dures can be especially useful while the periodontalhealth status of an abutment tooth over an extendedperiod of time is evaluated.2 Long-term provisionaltreatment also allows for improved interproximal accessduring periodontal therapy.15 The maintenance of long-term provisional treatment in concert with proceduressuch as alveoloplasty, tissue augmentation, dental im-plant placement, endodontic therapy, and orthodonticsis frequently useful.14

It can be challenging for practitioners to justify theuse of provisional treatment because of its temporarynature, especially when the time required to produce asuitable interim restoration equals that spent for toothpreparation and impression making.16 However, the ex-clusion of this essential step and the quality of the pro-visional restoration can be the difference between overalltreatment success and failure.3-5,17,18 The terms provi-sional, interim, or transitional have been routinely usedinterchangeably in the literature. The use of the termtemporary, however, is controversial and is consideredinappropriate by some because provisional restorationsserve many functions, and temporary treatment maybe interpreted as one of lesser importance or value.5,12,19

Provisional restorations should be the same as definitiverestorations in all aspects, except for the material fromwhich they are fabricated.4,20-22 Provisional treatment asan adjunct to some procedures such as porcelain veneersor implant prosthodontics may be occasionally unneces-sary.23,24

The purpose of this article is to review provisionalfixed prosthodontic treatment. The literature wassearched using Medline, and references were limited topeer-reviewed, English-language publications from1970 to the present.

MATERIAL FOR PROVISIONALRESTORATIONS

Interim treatment promotes numerous adjunct ben-efits to definitive prosthodontic treatment. The materi-als and techniques used for these purposes must reflectthese variable treatment demands and requirements.Consistent with nearly all areas of dental managementwhere material science plays such a significant role, thereis presently no ideal provisional material suitable for all

clinical conditions, however, there are many materialsthat have been used successfully for this purpose.25 Therequirements needed for provisional materials are shownin Table II. Many of these requirements such as appro-priate marginal adaptation, low thermal conductivity,non-irritating reaction to the dental pulp and gingivaltissues, ease of cleaning, ease of contour, and ease ofalterability and repair are extremely important to thesuccess or failure of treatment outcomes.2

For others, specific clinical treatments have a varietyof mandates for these materials and the importance ofthese requirements vary accordingly. For instance, ante-rior provisional restorations usually have higher estheticdemands than those needed for the posterior region.26

Long-span fixed partial denture (FPD) treatment re-quires provisional materials and techniques that providegreater tensile strength relative to single-unit restora-tions.27 Long-term use of provisional restorations re-quires materials that are more durable because of theirlonger period of service.16,28

Provisional material selection should be based on thestrengths and weaknesses of a given material relative tothe clinical mandates for specific treatments.25 Differingclinical techniques, such as indirect interim fabrication,2

may be required to accommodate certain situations.16

Finally, among differing proprietary material brands ex-hibiting similar chemical composition and physicalproperties, experience and personal preference is an im-portant consideration in material selection.25

Mechanical, physical, and handling properties, as wellas biocompatibility, will influence material selection infabricating provisional restorations.29 A material shouldbe easy to handle, provide adequate working time, and

Table II. Requirements for provisional restorations

Good marginal adaptation; adapts well to a tooth and matrixsurface

Adequate retention and resistance to dislodgment during normalmasticatory function

Strong, durable, and hardNonirritating to pulp and other tissues; low exothermicityNonporous and dimensionally stableComfortableEsthetically acceptable shade selection; translucent tooth-like

appearanceColor stablePhysiologic contours and embrasuresEasy to mix and load in the matrix, fabricate, reline, and repair;

relatively short setting timePhysiologic occlusionConductive to routine oral home-care cleaning proceduresFinishes to a highly polished, plaque- and stain-resistant surfaceEasy to remove and re-cement by the dentistRelatively inexpensiveLow incidence of localized allergic reactions

Modified from Federick5 and Krug.10

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NOVEMBER 2003 475

be nontoxic. Treatment complications such as chemicalinjury from the presence of monomer residue, thermalinjury from an exothermic polymerization reaction, andmechanical injury resulting from polymerization shrink-age must be considered.30 Likewise, after fabrication,considerations such as preventing repairs and remakesoften continue to be a direct reflection of the physicalproperties of a provisional material.29 Interim restora-tions are generally fabricated using 1 of 2 techniques: (1)custom fabrication; or (2) fabrication with preformedmaterials. Additionally both of these procedures can beaccomplished with direct clinical, indirect laboratory, ordirect/indirect combination techniques.2 Indirect tech-niques may result in an increased cost of fabrication andmay require special equipment and increased nonclinicaltime for fabrication.31

Custom-fabricated materials

Custom fabrication represents one of the best choicesfor provisional restorative treatment.32 The techniqueallows for intimate contact between a provisional resto-ration and prepared tooth. It provides a continuousmechanism for a variety of alterations during treatmentsuch as marginal adaptation, contour change, shade ad-justment, occlusal modification, and repair.

Provisional materials have been divided into the follow-ing categories based on how they are converted from plas-tic to solid-elastic masses: (1) chemically activated autopo-lymerizing acrylic resins; (2) heat activated acrylic resins;(3) light-activated acrylic resins; (4) dual light and chem-ically activated acrylic resins; and (5) others (alloys).2 Themost common materials used for custom interim fixed res-torations are acrylic resins.13,33 Generally, acrylic resinsused for provisional restorations are brittle,34 but theirgreat advantage is the ease with which they can be alteredby additions and subtractions.2,15 Several types of acrylicresin materials are available for interim restorative treat-ment2,32,35: (1) polymethyl methacrylate resins; (2) poly-ethyl methacrylate resins; (3) other types or combinations

of unfilled methacrylate resins; and (4) composites. A com-parison of physical properties associated with a variety ofprovisional materials is presented in Table III. 25 Compar-ative advantages and disadvantages of provisional materialsare listed in Table IV.2,3,9,10,14,19,25,27,32,34,36-57

Methacrylate resins

Autopolymerizing polymethyl methacrylate(PMMA) first appeared around 194045 and remains themost frequently used material for fabrication of interimrestorations.3,13,29,48 Plant et al58 found that the in-trapulpal temperature rise associated with the polymer-ization of methyl methacrylate materials could be up to5 times that associated with the normal consumption ofthermally hot liquid. The literature indicates that poly-methyl methacrylate is the preferred material when pro-visional restorations are made using indirect tech-niques.3,39

As seen in Table IV, ethyl methacrylate, introduced inthe 1960s,44 has a number of advantages and disadvan-tages relative to methyl methacrylate. One study,59

however, showed the highest value of fracture resistancewith an ethyl methacrylate material relative to methylmethacrylate and bis-acryl materials. Ethyl methacrylatemay be a better selection for direct interim prosthesisfabrication2 and is best suited for short-term use relativeto methyl methacrylate.10,32 Two other chemically sim-ilar materials, vinyl-ethyl and butyl methacrylate, displaycomparable clinical behavior to polyethyl methacrylate.Commercially available unfilled methacrylate materialsare listed in Table V.

Composite

Composite provisional materials encompass a fairlyvariable category by virtue of the fact that they are chem-ically comprised of a combination of 2 or more types ofmaterial. Most of these materials use bis-acryl resin, ahydrophobic material that is similar to bis-GMA. When

Table III. Comparison of physical properties for fixed provisional resin restorations

Desired physical propertiesMethyl

methacrylate Ethyl methacrylateBis-GMAcomposite

Visiblelight-polymerized

composite

Minimal temperature change during polymerization Surface hardness Marginal fit Wear resistance Transverse strength No valuetoo rubbery Transverse repair strength Surface roughness and polishability Color stability Stain resistance

Modified from Wang et al.25

, Most desirable comparative value; , Least desirable comparative value.

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this resin is mixed with inorganic, radiopaque filler itcombines to provide an interim treatment material thatis similar to composite restorative materials. Typicallythese materials use a variety of multifunctional acrylic

resin monomers that produce high-density cross link-ages during polymerization. Consequently they exhibita unique rubbery stage during the polymerization pro-cess.14 These materials are available as autopolymerized,

Table IV. Reported clinical advantages and disadvantages for custom provisional materials

Material type Clinical advantages Clinical disadvantages

Methyl methacrylate Durability2,25,32,27,42 (controversial) Poor durability44,48 (controversial)Color stability and esthetics32,37 Exothermic polymerization2,14,19,38,39

Good marginal adaptation2,25 Polymerization shrinkage9,14,22,32

Capable of high polish2,25 Poor wear resistance25

Relatively inexpensive2,14 Pulpal irritation associated with excessfree monomer2,14,40,41,45

Strong odor10,45

Ethyl methacrylate Lower exothermic reaction2,14,19,42 Low tensile strength14,25,43

Low polymerization shrinkage2,14,42 Poor surface hardness25

Good handling characteristics14 Poor wear resistance2,25

Good polishability25 Poor durability2,25

Good stain resistance25 Poorer color stability2,3,25,36,46

Less pungent odor10

Good toughness14

Bis-GMA composite Good surface hardness47 (controversial) Poor surface hardness25 (controversial)Easy to use14 Expensive14

Low exothermic reaction14,25,38 Brittle2,59

Low polymerization shrinkage14 Alterations and repairs are difficult2,27

Good marginal adaptation25,50,51 Poor stain resistance25

Good wear resistance25 Less polishability14

Good color stability25 (controversial) Poor handling characteristics3,52

Minimal pulpal irritation49 Poor color stability41 (controversial)

Visible light-polymerizedcomposite

Low temperature change25 (controversial) Poor marginal fit25

Good color stability25 (controversial) High temperature change25 (controversial)Controllable working time54 Poor color stability57 (controversial)Good surface hardness25 Poor stain resistance25

Good wear resistance25 Limited shade availability54

Good transverse strength25,34 Relatively expensive56

Brittle55

Table V. Unfilled methacrylate materials and manufacturers for custom fabricated provisional fixed prosthodonticrestorations

Material classification Product name Manufacturer

Methyl methacrylate Alike GC America, Alsip, III.Coldpac Motloid, Chicago, III.Duralay Reliance Dental, Worth, III.Jet Lang Dental, Wheeling, III.Temporary Bridge Resin L.D. Caulk, Milford, Del.Trim Plus Harry J. Bosworth, Skokie, III.True Kit Harry J. Bosworth, Skokie, III.Unifast LC GC America, Alsip, III.

Ethyl methacrylate Splintline Lang Dental, Wheeling, III.

Vinyl ethyl methacrylate Snap Parkell, Farmington, NYTrim Harry J. Bosworth, Skokie, III.Trim II Harry J. Bosworth, Skokie, III.

Butyl methacrylate Temp Plus Ellman Int, Hewlett, NY


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dual- (auto/visible light) polymerized, or visible light-polymerized forms.

Most of the composite materials are now availablewith an auto-mix delivery system similar to polyvinylsi-loxane impression materials. This makes them quick andeasy to use, but expensive.14 Diaz-Arnold et al47 showeda general decrease in hardness over time for 2 out of 3composite materials tested. This is consistent with Ire-land et al60 who showed that the bis-acryl materials ex-hibited higher flexural elastic moduli and moduli of rup-ture values at 24 hours but exhibited the greatestdecrease in these values over time.

Varnish materials designed to coat provisional resto-rations and produce a smoother surface are commer-cially available but are not advisable.61 Bis-acryl materi-als are compatible with other composite materials, butalterations for repairs and addition are difficult.2,27 Infact, Koumjian and Nimmo27 showed an 85% decreasein transverse strength after repair of a bis-acryl material.They suggested that it might be more advantageous tomake a new provisional restoration than repair this ma-terial.27 Young et al50 compared bis-acryl and polym-ethyl methacrylate materials in terms of occlusion, con-tour, marginal fidelity, and finish. For both anterior andposterior teeth, they found the bis-acryl materials signif-icantly superior to PMMA in all categories. Anotherreport makes similar comments.62

Some practitioners find bis-acryl materials difficult tomanipulate before setting because of difficult handlingproperties.1,3,35,52,53 Conversely, it has also been re-ported that dual-polymerized materials provide a morerigid rubbery stage where considerable adjustment andevaluation can be made before the final photopolymer-ization.29

Two other studies have discouraged the use of dual-polymerizing materials because of technique sensitivi-ty.1,51 Luthardt et al1 compared the clinical performanceof autopolymerizing, dual-polymerizing, and visiblelight-polymerizing bis-acryl materials. They concludedthat the light- and dual-polymerizing materials did notoffer a clinical benefit relative to autopolymerizing. Re-duced flexibility of the partially polymerized materialsmade them difficult to handle, which lead to complica-tions with the integrity of provisional restorations. Tjanet al51 stated that handling techniques might contributeto problems with marginal accuracy.

Visible light-polymerized resin

The visible light polymerized (VLC) materials, firstintroduced in the 1980s,44 require the addition of ure-thane dimethacrylate, a resin whose polymerization iscatalyzed with visible light energy and a camphoroqui-none/amine photo initiator.34,55,60 These materialsusually incorporate a filler such as microfine silica toimprove physical properties such as reduced polymeriza-tion shrinkage.53 Unlike methacrylate resins, they donot produce residual free monomers after polymeriza-tion, which explains why they exhibit significantly de-creased tissue toxicity relative to methacrylate resins.63

Haddix54 indicated that VLC materials could produceprovisional restorations with quality similar to heat-po-lymerized, laboratory-processed restorations, but withless time and expense. Dual-polymerizing compositematerials generally incorporate both chemically poly-merized bis-acryl and light-polymerized urethanedimethacrylate resins in variable product-specific com-binations. Commercially available composite materialsare listed in Table VI.

Table VI. Composite materials and manufacturers for custom fabricated provisional fixed prosthodontic restorations


Bis-acryl composites (Auto-polymerized) Bis Jet Lang Dental, Wheeling, III.Integrity L.D. Caulk, Milford, Del.Luxatemp Zenith/DMG, Englewood, NJProtemp II ESPE, Plymouth Meeting, Pa.Protemp Garant ESPE, Plymouth Meeting, Pa.Provitec GC America, Alsip, III.SmarTemp Parkell, Farmington, NYTemphase Kerr Dental, Orange, Calif.Turbo Temp Danville Materials, San Ramon, Calif.Ultra Trim Harry J. Bosworth, Skokie, III.

Bis-acryl composite (Dual-polymerized) Iso Temp 3M Dental, St. Paul, Minn.Luxatemp Solar Zenith/DMG, Englewood, NJLuxa-Flow (repair material) Zenith/DMG, Englewood, NJProvipont DC Ivoclar/Vivadent, Amherst, NY

Urethane dimethacrylate composite(Visible light-polymerized)

Triad Dentsply Int, York, Pa.



Preformed materials

Preformed provisional crowns or matrices usuallyconsist of tooth-shaped shells of plastic, cellulose ace-tate, or metal. They are commonly relined with acrylicresin to provide a more custom fit before cementation,but the plastic and metal crown shells can also be ce-mented directly onto prepared teeth using a stiff lutingmaterial following adjustment.14 They are commerciallyavailable in various tooth sizes and are usually selectedfor a particular tooth anatomy. Nonetheless, availablesizes and contours are finite which makes the selectionprocess important for clinical success. Compared withcustom fabricated restorations, this treatment method isquick to perform but is more subject to abuse and inad-equate treatment outcome. This can result in improperfit, contour, or occlusal contact for a provisional resto-ration.32

Polycarbonate resin

Polycarbonate resin is commonly used for preformedcrowns and possesses a number of superior propertiesrelative to polymethyl methacrylate materials.5,64 Thesecrowns combine microglass fibers with a polycarbonateplastic material.14 Practitioners commonly use polycar-bonate resin shell crowns as a matrix material around aprepared tooth that is relined with acrylic resin to cus-tomize the fit.5 This material possesses high impactstrength, abrasion resistance, hardness, and a good bondwith methyl-methacrylate resin.64

Metal

Metal provisional materials are generally estheticallylimited to posterior restorations. Aluminum shells pro-vide quick tooth adaptation due to the softness andductility of the material, but this same positive qualitycan also promote rapid wear that results in perforation infunction and/or extrusion of teeth.14 An unpleasanttaste is sometimes associated with aluminum materi-als.14 Iso-Form Crowns (3M Dental Products, St. Paul,Minn) are manufactured with high-purity tin-silver andtin-bismuth alloys. Like aluminum, they possess reason-able ductility and can be contoured quickly, but theocclusal table is reinforced so they are more resistant to

wear related failure.14 For longer-term use, nickelchrome and stainless steel crowns are available but maybe more difficult to adapt to a prepared tooth.14 Com-mercially available preformed materials are listed in Ta-ble VII.

INFLUENCE OF MATERIALPROPERTIES ON TREATMENTOUTCOMEMarginal accuracy

Accurate marginal adaptation of resinous provisionalrestorations to the finish line of a prepared tooth assistsin protecting the pulp from thermal, bacterial, andchemical insults.65 Barghi and Simmons66 indicated thatfrom their qualitative assessment, autopolymerizingacrylic resin provisional restorations routinely did nothave adequate marginal adaptation. The accuracy couldbe significantly improved by relining the restoration af-ter the initial polymerization. Furthermore, they foundthat because of hydraulic pressure, 80% of restorationsdid not fully reseat after the reline procedure. They sug-gested that this problem could be improved by venting aprovisional restoration before reline.

Crispin et al67 evaluated marginal accuracy with di-rect and indirect techniques. They reported that indirectfabrication provided significant improvements in mar-ginal fit relative to direct methods when methyl andvinyl ethyl methacrylate resins are used. They demon-strated that the marginal fit of polymethyl methacrylaterestorations could be improved by up to 70% with anindirect technique. Other reports showed similar re-sults.56,68

A number of studies have focused on the effects ofthermocycling on provisional crown margins.69-73 Theyreported that (1) acrylic resin provisional crowns dem-onstrated dimensional degeneration and enlarged mar-ginal gaps resulting from thermocycling and occlusalloading; (2) marginal gap changes were greater after hotthermocycling than cold thermocycling; (3) improvedmarginal accuracy of PMMA provisional restorations oc-curred when a shoulder finish line was used comparedwith a chamfer marginal design; (4) in addition to im-proved initial accuracy, provisional resin restorationsthat were relined had smaller marginal changes after

Table VII. Preformed materials and manufacturers for provisional fixed prosthodontic restorations


Polycarbonate resin B-Crowns Harry J. Bosworth, Skokie, III.Polycarbonate Crowns 3M Dental, St. Paul, Minn.

Polycarbonate resin Molar B-Crowns Harry J. Bosworth, Skokie, III.

Nylon fiber reinforced metal Iso-Form Crowns (tin/silver alloy) 3M Dental, St. Paul, Minn.Gold Anodized Crowns (gold anodized aluminum) 3M Dental, St. Paul, Minn.Stainless Steel Crowns (nickel chrome) 3M Dental, St. Paul, Minn.


NOVEMBER 2003 479

thermocycling and occlusal loading; and (5) light-poly-merized materials provided significantly improved mar-ginal accuracy relative to autopolymerizing PMMA resinafter thermocycling. In contrast, Keyf and Anil74 con-cluded that the marginal discrepancy found with bis-acryl resin was significantly greater with a shoulder finishline after 1 week relative to a chamfer design.

Koumjian and Holmes75 examined a variety of resin-ous provisional materials and reported that they all dem-onstrated continued polymerization shrinkage afterstorage in air for 1 week. When stored in water for 1week, water absorption compensated for polymerizationshrinkage in all of the materials except for polyvinylethylmethacrylate and bis-acryl materials. The water storageenvironment was the most clinically relevant in thisstudy and produced significantly lower marginal dis-crepancies with the PMMA and ethyl methacrylate ma-terials.

Lepe et al68 reported that polymerization shrinkageof acrylic resin would play an important role in the fit ofprovisional restorations. Volumetric polymerizationshrinkage for polymethyl methacrylate is 6% comparedwith 1% to 2% for composite materials. They speculatedthat composite materials would provide a better mar-ginal fit relative to unfilled polymethyl methacrylate be-cause of less polymerization contraction, but the authorsalso pointed out that marginal fit is not the only factoraffecting the overall retentive quality of provisional res-torations. They found a nearly 20% improvement in theretention of interim crowns made with polymethylmethacrylate compared to those fabricated with com-posite materials. They concluded that polymerizationshrinkage occurring with the polymethyl methacrylatematerial might have allowed for a tighter fit of the res-toration on the prepared tooth, which had a direct in-fluence on improved retentive quality.

Color stability

In esthetically critical areas it is desirable for provi-sional restorations to provide an initial accurate colorshade match and then to remain color-stable over thecourse of provisional treatment.26 Discoloration of pro-visional materials can produce serious esthetic complica-tions, especially when long-term provisional treatment isrequired. Modern provisional materials use stabilizersthat decrease chemically induced color changes, butthese materials are susceptible to other factors that willpromote staining.36,37,76 Most provisional materials aresubject to sorption, a process of absorption and adsorp-tion of liquids that occurs relative to environmental con-ditions.26,36 When provisional materials contact pig-mented solutions such as coffee or tea, discoloration ispossible.37,76 Porosity and surface quality of provisionalrestorations,36,74,77 as well as oral hygiene habits,26 canalso influence color changes.

Crispin and Caputo36 studied the color stability ofprovisional materials. They found that methyl methac-rylate materials exhibited the least darkening, followedby ethyl methacrylate and vinyl-ethyl methacrylate ma-terials. They also reported that increases in surfaceroughness induced increases in material darkening andpressure polymerizing did not influence discolorationrelative to air polymerizing. Koumjian et al57 included avisible light-polymerized material in their investigation.They placed test materials into the flanges of completedentures and concluded that for short time periods of 5weeks or less, all materials demonstrated acceptablecolor stability. They stated, however, that the TriadVLC material exhibited more adverse color change rel-ative to other materials at the end of 9 weeks.

Yannikakis et al37 immersed provisional materials invarious staining solutions for up to 1 month. They re-ported that all materials showed perceptible colorchanges after 1 week. After 1 month, the methylmethacrylate materials exhibited the best color stabilityand bis-acryl materials the worst.

Robinson et al78 reported on the effect of vital toothbleaching on provisional restorative materials. They pre-pared disks of polymethyl, polyethyl, polybutyl methac-rylate, and bis-acryl composite materials. Polycarbonatecrowns were also studied. Specimens of each type ofprovisional material were placed into a variety of propri-etary dental bleaching agents and soaked for up to 14days. They concluded that an orange discoloration oc-curred throughout the specimens representing allmethacrylate materials. The bis-acryl and polycarbonatecrowns showed no difference relative to the controlgroup. Another study confirmed the color stability ofcomposite materials during vital bleaching treatment.79

Monaghan et al80 found that vital bleaching producedvisibly lighter composite restorations. They reportedthat in some situations composite restorations mightlighten along with natural teeth that are simultaneouslybleached.

Gingival response

Inflammation and recession of the free gingival mar-gin associated with provisional treatment is a commonoccurrence.81-84 Donaldson81 reported the followingobservations regarding gingival recession: (1) the pres-ence of a provisional restoration lead to at least somerecession at about 80% of the free gingival margin sitesevaluated; (2) the degree of recession was time depen-dant; (3) placement of the definitive treatment com-monly lead to gingival recovery; (4) 10% of subjectsdemonstrated recession in excess of 1 mm; and (5) in thepresence of gingival recession, only one third of subjectsdemonstrated complete gingival recovery.

In a separate report, Donaldson82 indicated that theoccurrence of gingival recession before provisional treat-



ment was directly linked to further recession observedafter the completion of definitive prosthodontic treat-ment. A history of bone loss and subsequent gingivalrecession would suggest that a patient would have anadverse reaction to provisional fixed prosthodontictreatment. He also found a direct relation between thedegree of pressure applied by a provisional restorationand gingival recession. An anatomically contoured pro-visional restoration caused less recession than did a non-anatomically contoured one.

In contrast, MacEntee et al,85 in a histologic evalua-tion of tissue response, reported no detectable change ingingival tissue associated with provisional restorativetreatment over a 3 week period. Waerhaug and Zander83

found that in the presence of mechanical irritation suchas poor restorative contours, provisional treatment didnot negatively alter gingival tissue response. Rather,they implicated the presence and accumulation of ne-crotic tissue and plaque material in areas associated withpoor marginal adaptation and surface roughness of in-terim restorations as a constant source of inflammationto the gingival tissues leading to diminished gingivalhealth. Garvin et al84 concluded that periodontal inflam-mation associated with provisional treatment could beexpected to be a reversible process provided that theamount of gingival irritation is minimal and provisionaltreatment occurs over a short time span.

Pulpal response

Dental pulp inflammation can be caused by eitherthermal or chemical insult resulting from materials usedto produce direct provisional restorations.38,49,86,87

Tjan et al86 studied the dental pulp chamber tempera-ture rise associated with the direct fabrication of provi-sional restorations. In this in vitro study, a thermocoupleprobe was placed into the pulp chamber of specimenteeth to measure the exothermic reaction associatedwith the direct contact polymerization of methylmethacrylate, ethyl methacrylate, vinylethyl methacry-late, and bis-acryl materials. Although the bis-acryl ma-terial produced the lowest temperature increase, no sig-nificant differences were found among the 4 types ofmaterials tested. The results of this study suggest thepossibility of thermal damage to dental pulp tissue andodontoblasts during direct provisional fabrication, butthe authors also indicated that actual damage could onlybe accurately assessed by use of histologic studies. Theysuggested that by use of air and water coolants, as well asby use of a matrix material, that can dissipate heat rap-idly, the pulp temperature rise might be reduced. Addi-tionally, the amount of heat rise is dependent on thequantity of provisional restorative material used.

Other studies have found comparable results withsimilar methods.38,87 Moulding and Teplitsky38 re-ported that intrapulpal temperature rise was dependent

on the type of acrylic resin, and the type of matrix usedto retain the material on the tooth during polymeriza-tion. Temperature rise was greatest with polymethylmethacrylate and vacuum adapted templates; least withbis-acryl and relined resin shells; and intermediate tem-perature increases were recorded with polyethyl methac-rylate materials and either irreversible hydrocolloid orpolyvinylsiloxane impression materials used as a matrixfor holding acrylic resin provisional material against atooth. The authors also identified that fixed partial den-ture provisional restorations produced a greater temper-ature rise than did single-unit provisional restorations.

Grajower et al87 showed that faster polymerizingacrylic resin materials could generate higher tempera-tures than slower polymerizing resins. They indicatedthat external heat dissipation might be enhanced with awater spray or by polymerization of restorations in sili-cone impressions. Additionally, this external heat dissi-pation caused retardation in the polymerization, whichfurther decreased heat production. The retardation re-sulted from the cooling effect of the spray and not thewater itself, since moisture quickens the polymerizationof autopolymerizing acrylic resins that contain tertiaryamine accelerators. The authors concluded that (1) pro-visional acrylic resin restorations might be fully polymer-ized on prepared teeth by appropriate methods such asin impressions or with external cooling, without causingexcessive heating of the dental pulp; (2) removal of aprovisional restoration before complete polymerization,leading to potential deformation of the acrylic resin ma-terial, is therefore unnecessary; and (3) a thin insulatinglayer should be applied to a prepared tooth before con-tact with nonpolymerized acrylic resin to avoid chemicalinjury.

Hypersensitivity

Hypersensitivity from provisional materials has beenreported but appears to be rare.88-90 Autopolymerizingmethacrylate materials have greater potential for pro-ducing allergic contact stomatitis than similar heat-po-lymerized materials.90 The residual monomer in the ma-terial has been implicated as the causative factor.90 Onereport showed that the residual monomer content inheat-polymerized acrylic resin ranges from 0.045% to0.103%. Autopolymerized acrylic resin has a residualmonomer content of 0.185%. Over time residual mono-mer is gradually leached out, leaving a fraction that istightly bound to the resin material.88

Allergic reaction to provisional materials will demon-strate the following features: (1) the patient has hadprevious exposure to the provisional material; (2) thereaction conforms to a known allergic pattern, such asredness, necrosis, or ulceration; (3) the reaction resolveswhen a provisional restoration is removed; 4) reactionrecurs when a provisional restoration is replaced; and 5)


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a patch test for the material is positive.90 Patch testinghas demonstrated less response with light-polymerizedmaterials relative to autopolymerizing acrylic resin.89 In-direct material processing methods are recommendedfor individuals showing evidence of hypersensitivi-ty.89,91 After complete polymerization, the polymerizedacrylic resin usually does not induce allergic reactions.Unpolymerized monomer can be substantially removedby placing an autopolymerized provisional restoration ina pressure pot with warm water for 20 minutes.89

Strengthening provisional materials

The literature clearly favors acrylic resin as the mate-rial of choice for provisional restorations.33 Most resinsused for provisional restorations are brittle.34 Repairingand replacing fractured provisional restorations is a con-cern for both clinician and patient because of additionalcost and time associated with these complications.33

Failure often occurs suddenly and probably as a result ofa crack propagating from a surface flaw.34 The strengthand serviceability of any acrylic resin, especially in long-span interim restorations, is determined by the materi-als resistance to crack propagation.43,92,93 Crack prop-agation and fracture failure may occur with thesematerials because of inadequate transverse strength, im-pact strength, or fatigue resistance.48

Physical properties of strength, density, and hardnessmay predict the longevity of provisional restorations.Donovan et al92 examined methods to improve the lon-gevity of these restorations using variable indirect poly-merization techniques. They compared methyl methac-rylate material strength, porosity and hardness under thefollowing polymerization conditions: (1) in air; (2) un-der water; (3) under air pressure; and (4) under waterand air pressure. They found that polymerization with apressure vessel with air and water had the greatest influ-ence on increasing strength and reducing porosity.There was no difference in hardness for the 4 conditionstested. A similar study, however, evaluated the fracturetoughness of provisional resins and found that the use ofa pressure vessel during polymerization did not signifi-cantly increase the fracture toughness for the resins test-ed.43 Covey et al94 found that oven heat treatments at120C for 7 minutes could significantly increase thetensile strength for both chemical and light-polymerizedcomposite materials.

Heat-polymerization of acrylic resin materials can beused when provisional restorative treatment will be re-quired for extended periods of time or when additionalstrength is required. This indirect laboratory process re-sults in materials that are denser, stronger, more wearresistant, more color stable, and more resistant to frac-ture than their autopolymerizing counterparts.3,95

Metal castings and swaged metal substructures in com-bination with resin materials have been incorporated

into provisional restorations and have been reported asespecially useful with long-term or long-span interimtreatment.5,95,96 Both heat-polymerized acrylic resinand metal provisional restorations should last longerthan autopolymerized restoration, but the expense andtime required for indirect fabrication can make them lesscost effective for routine use.97

Reinforcing frameworks reduce flexure, increase re-tention,95 and increase structural integrity.98 Attemptshave been made to strengthen acrylic resin materials byreinforcement with either chemical modification withgrafted co-polymers and stronger cross linkage or byinclusion of various organic and inorganic reinforcingfibers.48 Materials used for fiber reinforcement have in-cluded metal, glass, carbon graphite,99,100 sapphire,Kevlar (Du Pont, Wilmington, Del),101 polyester, andrigid polyethylene.48 Most of these materials have hadlittle or no success in increasing resin strength.99

Investigations on fiber reinforcement have favoredthe use of long continuous fibers, with strand alignmentplaced perpendicular to the direction of appliedloads.102 Samadzadeh et al102 studied the effects of plas-ma-treated woven polyethylene fiber (Ribbond Inc, Se-attle, Wash) on the fracture strength of methyl methac-rylate and bis-acryl materials. Fracture strength wasincreased for the bis-acryl material. Ribbond fibers didnot increase the fracture strength of PMMA prostheses,but complete catastrophic fracture was avoided. Powellet al28 compared Kevlar 49 polyaramid fiber (Du Pont)with stainless steel wire as a way of reinforcing provi-sional fixed partial dentures made with methyl methac-rylate resin. They found that the wire configuration pro-duced a superior stiffness and toughness.

Zuccari et al103,104 studied methods to promote astronger resin matrix by decreasing crack propagation.They reported that when admixed zirconium oxidepowders were added to unfilled methylmethacrylateresin, the resultant composite material exhibited signif-icant improvements in the modulus of elasticity, trans-verse strength, toughness, and hardness, even thoughwater sorption over time had a negative influence onmechanical properties.

Emtiaz and Tarnow,44 Davidoff,31 Caputi et al,98 andothers8,12,16,17,55,96,105,106 have described variousmethods of adding metal reinforcing structures toacrylic resin provisional restorations; castings, spotwelded stainless steel matrix bands, and precut stainlessmesh have been used. Generally margins are not repro-duced in the cast alloy. Yuodelis and Faucher17 de-scribed using stainless steel wire material while Hazeltonand Brudvik105 reported the benefits of stainless steelorthodontic band material adapted around abutmentteeth, removed, welded, and fitted inside acrylic resinshell crowns to reinforce autopolymerizing acrylic resinmaterials. Similarly, Greenburg107 recommended ultra-thin stainless steel bands. Spot-welded stainless steel



bandreinforced acrylic resin provisional restorations arestiffer and more resistant to cement degradation and lossof cement seal from deformation.33 Fabrication of a re-inforcing metal framework is guided by a diagnosticwax-up that generates the desired contours for the fin-ished provisional.95

In a study describing a negative influence on thestrength of provisional materials, Chee et al108 studiedthe effect of chilled monomer on the working time for 3autopolymerizing acrylic resins. They found that theworking and setting times increased by up to 4 minuteswhen chilled monomer was used, but the transversestrength for the materials were decreased by 17%.

Provisional luting materials

Provisional luting agents should possess good me-chanical properties, low solubility, and tooth adhesionto resist bacterial and molecular penetration.11 Themost important function of these materials is to providean adequate seal between the provisional restoration andprepared tooth.68 This is necessary to prevent marginalleakage and pulpal irritation.11,68 There are a variety ofluting materials used for interim purposes. The mostcommon include (1) calcium hydroxide; (2) zinc-oxideand eugenol; and (3) noneugenol materials.11 Gener-ally, all of these possess poor mechanical properties thatlikely worsen over time. This can have a negative influ-ence on marginal leakage but also provides an advantageby allowing easier dislodgment and removal of provi-sional restorations from teeth.11

The retentive requirements for provisional luting ma-terials are that they be strong enough to retain a provi-sional restoration during the course of treatment butallow easy restoration removal when required.68 Thisparadoxical necessity for good retentive and sealingquality and easy restoration retrieval may lead to a com-promise in material behavior, particularly regarding me-chanical properties.11 Baldissara et al11 recommendedthat interim restorations be frequently evaluated andused for only short periods of time. Literature reportsadvise that if provisional treatment is required over aprotracted time period, it is best to remove and replacethe provisional luting agent on a regular basis.11,21

Some of the most commonly used cements with pro-visional prostheses are those containing zinc-oxide andeugenol.11 They provide sedative effects that reducedentin hypersensitivity and possess antibacterial proper-ties.11 Unfortunately, free radical production necessaryfor polymerization of methacrylate materials can be sig-nificantly hampered by the presence of eugenol found ineugenol based provisional luting materials.14 This caninterfere with the acrylic resin polymerization and hard-ening process.109 They can also be incompatible withsome resin-based definitive luting agents for the samereason.11

Eugenol-free provisional luting materials are com-mercially available and have gained popularity due to theabsence of resin-softening characteristics.109 Gegauffand Rosenstiel,110 however, reported that Temp-Bond(Kerr Dental, Orange, Calif) a zinc-oxide and eugenolbased cement did not appear to have a significant ad-verse effect on the polymerization of acrylic resins. Theypostulated that the softening effect of eugenol on acrylicresin is dependent on the presence of unreacted euge-nol, which may be minimal in Temp-Bond cement.

CLINICAL CONSIDERATIONS FORPROVISIONAL TREATMENTINVOLVING NATURAL TEETH

The literature describing the fabrication of provi-sional restorations is extensive but largely anecdotal.Virtually all teeth receiving cast restorations require pro-visional restorations. Properly executed provisional re-storative treatment rarely fails and dislodgment or frac-ture usually indicates that their form is unacceptable orthat a tooth preparation is inadequate. Provisional res-torations should be smooth, highly polished, and alter-able and for this reason custom made provisional resto-rations most consistently meet the biological,functional, and esthetic needs of a patient.2 The brand ofprovisional material and method of fabrication are not asimportant as the devotion, skill, and attention to detailof the dentist.22

Provisional restorations as part ofcomprehensive treatment

Provisional restorations are not devoid of interactionswith other modes of therapy. Patients often have peri-odontal, endodontic, orthodontic, or surgical needs inconjunction with their prosthodontic treatment. Provi-sional restorations produce outcomes that range frommicroscopic tissue effects to psychological factors thatchange a patients behavior.111 Provisional restorationscan provide patients with an increased confidence intreatment.4,111

Diagnostic provisional treatment

In the simplest situations, complete oral and extraoralclinical examinations, as well as radiographic evaluation,may be all that is necessary before commencing prosth-odontic treatment. In more complex treatments, how-ever, provisional restorations provide a means of design-ing, improving, and assessing the occlusion, esthetics,and contours for definitive restorations, as well as todetermine their effects on gingival health, phonetics,and patient adaptability before the initiation of the de-finitive treatment.6,12,112-114 Provisional restorations fitinto 2 categories: (1) those that fit within an arch offundamentally intact teeth that provide reference fortheir occlusion, contours, and esthetics; and (2) those


NOVEMBER 2003 483

that become the reference for the entire prosthe-sis.115,116 Provisional treatment for patients with morecomplex prosthodontic needs demands fabrication andarticulation of diagnostic casts and completion of a di-agnostic wax-up in the maxillomandibular relationshipin which definitive treatment is to be performed.2,30,117

Occlusal diagnosis and treatment

Casts of provisional restorations mounted oppositedefinitive casts transfer contours, clinical crown dimen-sions, and maxillomandibular relationships from a pa-tient to a dental laboratory for developing occlusal fac-tors, especially anterior guidance, for fixedprosthodontic treatment.2,4,5,118 Sometimes treatmentfeasibility can only be tested via full-arch provisionalrestorations and occlusal problems are best diagnosedduring a functional testing period with provisional treat-ment.15

Esthetic and phonetic diagnosis and treatment

Provisional restorations assist development and as-sessment of esthetic and phonetic values of the plannedfixed prosthesis.2,12,39,115,117,119 Zinner et al12 pro-posed use of guidelines to test anterior contours. Theyrecommended that the maxillary anterior incisal edgesfollow the contour of the lower lip, the smile line, andall 6 maxillary anterior teeth should be in contact withtheir antagonists in maximum intercuspation. Evalua-tion of labiodental (F and V) and sibilant (S andCH) sounds are useful methods of ascertaining thelengths of maxillary incisors.39 Matrixes created from adiagnostic waxing or from casts of provisional restora-tions are useful tools for producing specific contours in adefinitive prosthesis or communicating those conceptsto the dental laboratory.118-122 In certain situationsphonetics and esthetics of a planned prosthesis can beassessed before tooth preparation by use of vacuum orpressure-formed matrixes that hold autopolymerizingacrylic resin between unprepared teeth and proposedtooth contours to provide intraoral treatment simula-tion.117

Periodontal treatment and maintenance

Periodontal treatment is commonly part of compre-hensive prosthodontic care. These provisional restora-tions provide a matrix against which the tissue heals,guiding the generation of correct soft tissue architec-ture.123 According to Shavell,22 tooth preparations andprovisional restorations should be completed with re-traction cord in place. Patients should be seen weekly forevaluation and the provisional restorations are judgedsuccessful only when the gingival tissue reflects goodgeneral health. It has been recommended that when theduration of the periodontal treatment is less than 6months, the use of acrylic resin provisional restorations

should be adequate.17 For longer treatment periods,gold-band-and-acrylic-resin restorations are more ap-propriate.13,17 A provisional restoration also guidespreparation of teeth that require periodontal surgery.20

Poorly fabricated provisional restorations have conse-quences for fixed prosthodontic treatment including:gingival recession2; difficulty making impressions; diffi-culty fitting the definitive restorations9; soft tissue dam-age; and inefficient use of time at prosthesis insertion.3

Provisional restorations play a role in long-term peri-odontal therapy as well.15 Chlorhexidine used in con-junction with provisional treatment has been shown toreduce plaque levels and improve gingival indexes.124

Slightly convex facial and lingual contours of provi-sional restorations and a flat emergence profile are effec-tive in promoting gingival health.30 Good periodontalhealth can be created by developing the appropriatecontour and good gingival adaptation and embrasurespace of the prosthesis for the particular situation. Em-brasure spaces that are too broad can cause food impac-tion and blunting of the papilla.2

Orthodontic conjoint treatment

It is generally better to avoid crown preparation be-fore orthodontic treatment because after tooth move-ment; a tooth may be incorrectly prepared. However, inconjunction with tooth movement procedures, carefullyplanned provisional restorations can (1) replace hopelessor missing teeth to improve esthetics; (2) achieve occlu-sal stability with missing posterior teeth and maintainvertical dimension of occlusion; (3) retain teeth inproper position; (4) allow maturation of investing tis-sues; (5) allow evaluation of questionable teeth; and (6)provide anchorage where only a few teeth remain.125

Provisional fixed prosthesis fabrication

General concepts. According to Kopp126 provisionalfabrication involves 2 segments: (1)supragingival con-struction, the basic form providing abutment protec-tion, stabilization, and function; and (2)intrasulcularextension, marginal fit and correct contours to pro-mote soft tissue health. Central to this is the use of amatrix to produce the external form and adaptation ofmaterial replicating the contour of the prepared tooth orteeth. Provisional restorations are often made clinicallythough they may also be fabricated indirectly in thelaboratory. In contemporary practice, the majority ofprovisional restorations are made wholly or in part withautopolymerizing acrylic resin.3,13,29,48 Lubricants ap-plied to teeth or a cast with indirect methodology areoften recommended during fabrication of provisionalrestorations. The published preferences for lubricantmaterials used for these purposes are shown in Figure 1.

Adaptation to a prepared tooth. Adaptation is doneeither directly on a tooth or indirectly on a plaster, stone,



polyvinylsiloxane, or other replica of a preparedtooth.3,5,127 Representation of the internal surface ad-aptation, or intaglio, is typically accomplished by adapt-ing a plastic material such as acrylic resin or occasionallya cement, such as zinc oxide and eugenol to a tooth ortooth replica with an external shell or custom-made ma-trix. The internal surface adaptation is evaluated muchlike the surface of an impression.3,9

Cavosurface adaptation. Provisional restorationsmust be made of a material, which is alterable2 and canbe precisely adapted to prevent excessive cement filmthickness.30 A marginal gap usually exists at the interfacebetween tooth, provisional restoration, and cement al-lowing plaque to accumulate and compromise cementa-tion.30,128 Relining provisional restoration margins pro-duces the best adaptation as long as potential traumafrom monomer and the exothermic heat of reaction iscontrolled with methods such as external waterspray.129-131 Exposure of margins by placement of re-traction cord, not by electrosurgery,126 is recommendedduring fabrication directly on the teeth.9,22,53,126 Bur-nished copper or gold bands adapted to the cervical onethird of a prepared tooth and incorporated into a provi-sional restoration are reported to improve margin adap-tation, physiological contours, and hygiene,125,132,133

however, at least 1 report asserts that acrylic resin mar-gins can be as good as metal band margins.15

Posterior crown preparations can expose 1-2 milliondentinal tubules if all the enamel is removed.134 Dentinconditioners used with dentin bonding systems have

been shown to increase fluid flow through the dentin.134

Although dentin-sealing agents have demonstrated a re-duction in dentin tubule fluid flow, numerous sealantshave a significant film thickness at the margin area, someas thick as 263 m.134

Form. Provisional restorations should have cervicalconcavities and proper emergence profile.22 It has beensuggested that pontics should be designed for hygieneon the mandibular arch and hygiene and esthetics on themaxillary arch. The convex, bullet-shaped, pontic hasbeen suggested to be the easiest to keep clean.3

Liebenberg130 advocated avoiding splinted acrylicresin restorations whenever possible to promote betterhygiene, cement removal, and reuse. Others advocatesplinting adjacent provisional restorations together evenif the definitive treatment plan calls for individual defin-itive restorations.9 Burnished metal bands incorporatedin the provisional reportedly improve contours.125,132

Clinical methods

Matrices. Numerous references have appeared in theliterature since 1970 describing clinical fabricationmethods and the prevalence of these methods is shownin Figure 2. A matrix planned for provisional fabricationmay copy existing tooth contours from the mouth witha diagnostic cast119 or reproduce customized contourscreated by a diagnostic waxing.16 It is further suggestedthat, when possible, this matrix should extend onto at

Fig. 1. Prevalence in literature of lubricant materials fortooth-borne provisional restorations.

Fig. 2. Prevalence in literature of clinical fabrication meth-ods for tooth-borne provisional restorations.


NOVEMBER 2003 485

least 1 tooth adjacent to teeth being restored.53 Theaddition of acrylic resin, VLC resin, or even elastomericimpression materials can add contour to select areas ofcasts to correct extensively damaged teeth before mak-ing the matrix.135,136

Transparent thermoplastic materials may be vacu-um8,10,14,55,65,137-139 or pressure117,140 adapted to adental stone cast creating a matrix or external surfaceform. Transparent matrices can be used for provisionalfabrication, to guide tooth preparation,53 as a laboratoryaid, and can become a part of the patient records.139

Impression materials are useful for provisional matri-ces. Polyvinylsiloxane and irreversible hydrocolloid ma-trices serve functions other than providing an externalsurface form for the provisional restorations in that theycan limit thermal insults to pulpal tissues.38,87,141 A dis-advantage of polyvinylsiloxane as a matrix material is itshigh cost.35 Other materials such as baseplate wax havealso been used for matrices.142,143

Direct fabrication. For select patients, a denturetooth secured in position with typical class III compositerestorations and orthodontic wire may be a suitable pro-visional restoration for a missing mandibular incisor.144

For urgent situations, in the absence of any matrix oropportunity to create a matrix, a provisional restorationcan be fabricated by adapting a block of freshly mixedacrylic resin directly to a tooth. After the acrylic resinblock has polymerized, the tooth contours can be carvedwith acrylic resin burs of choice and the restorative mar-gins perfected intraorally.131

Most patients, however, require a more conventionalapproach. Fabricating provisional restorations directlyon teeth using the direct method is suitable for singleunits and up to 4-unit fixed partial denture provisionalrestorations, according to 1 report.126 Three techniquesencompass virtually all of the literature on direct provi-sional restorations: (1) use of a premanufactured provi-sional shell3,145-150; (2) use of an impression materi-al,14,17,52,130,151-157 or pressure or vacuum formedtranslucent matrix140,148; and (3) use of a custom, pre-fabricated acrylic resin shell.8,14,55,105,151,157-161

Prefabricated shell crowns are constructed from a va-riety of materials including aluminum, silver-tin, tin-bismuth, polycarbonate resin, celluloid, stainless steel,and nickel-chrome and can be used as matrices for directfabrication.3,14,147

Much more common in the literature is the use ofimpression materials or thermoplastic materials as shellmatrices. Direct provisional restorations made particu-larly of PMMA and, to a lesser degree, polyethyl methac-rylate (PEMA) must be cooled if the material is allowedto polymerize completely on a tooth; polymethylmethacrylate can increase pulpal temperatures as muchas 7C.141 Cooling the material during polymerizationby its removal at initial polymerization and allowingcomplete polymerization to be completed while it is off

the tooth, cooling with air-water spray, periodic re-moval, and flushing with water and use of a heat sinkmatrix material such as alginate will limit temperatureincreases to less than 4C, minimizing the exothermicrisk.162 Larger masses of exothermic materials such aswith FPD provisional restorations produce greater pul-pal temperature increases.162

Visible light polymerized materials produce smallerpulpal temperature increases and have extended work-ing time compared with PMMA or PEMA.38,141 Oneauthor55 recommended softening Triad material in120F to 150F water, creating a hollow in the centerof the softened material mass with a blunt instrumentbefore seating and lubricating the tooth as a method forreducing the viscosity of the material and promotingtooth adaptation. The adaptation was then evaluatedextraorally before polymerization.53 External colorantscan be applied either as autopolymerizing pigments or assuspensions within light polymerized unfilled acrylic res-ins.53 A number of reports30,163,164 have recommendedhybrid visible light-polymerized composite/PMMA di-rect provisional restorations. Fehling163 stated that thiscombination decreased occlusal and proximal wear andrecommended placing 3 coats of copal cavity varnish toprotect the tooth from deleterious effects of freemonomer.

Indirect fabrication. The indirect method has beenindicated to fabricate multiple unit provisional restora-tions to126 (1) avoid exposure of a patient to adverseproperties of provisional acrylic resins; (2) optimize theproperties of provisional acrylic resins; (3) allow the use ofmaterials that are difficult to polymerize intraorally; (4)make significant contour or occlusal changes; and (5) pro-vide for the fabrication of hybrid provisional restorations. Avariety of methods of creating an acrylic resin shell custom-ized for a patients occlusion or contours have been pub-lished.8,55,65,158,160,161 Many authors describe indirectmethods.18,31,35,44,96,98,121,127,135,156,165-168 Indirecttechniques generally use either approximate tooth prepa-rations made on a duplicate cast or a cast of the actual toothpreparations made after the clinical procedure has beenaccomplished. A matrix made from a diagnostic wax-upof planned treatment tooth contours can be placed overthe tooth preparations on the cast. Autopolymerizingacrylic resin can be packed into a matrix and fitted overthe prepared tooth cast or a diagnostic wax-up can beinvested and boiled out so that tooth-colored, heat-polymerized acrylic resin can be packed and pro-cessed.2,31 One advantage of the indirect technique isthat it can be allocated to auxiliary personnel.35

Fabricating a provisional restoration wholly or in partusing an indirect method reduces exposure of oral tis-sues to monomer, heat, shrinkage,121,169 and reducesthe volume of volatile hydrocarbons inhaled by a pa-tient. Creating an indirect acrylic resin shell of an unpre-pared tooth that is later relined intraorally is one method



of reducing patient exposure.157,161 Extensive shell ma-trices designed for adaptation and margin relining in themouth can be initially fabricated of polycarbonate orvisible light polymerized polymers.55,64

It has been reported that provisional restorations fab-ricated indirectly have superior margins to those fromdirect techniques because the acrylic resin polymerizesin an undisturbed manner.127,169 Polymerizing autopo-lymerizing acrylic resin under heat and pressure im-proves the physical properties of the material. Reinforc-ing the vacuum or pressure formed matrix allows it to besecured to the cast on which the provisional shell ispolymerized.8,156,170

The prevalence in the literature on polymerizingmethods for tooth supported provisional restorationmaterials is shown in Figure 3. The intraoral autopoly-merizing method is considerably more prominent in theliterature relative to other, particularly extraoral,methods.

Provisional treatment for all ceramic veneerrestorations

All-ceramic restorations including laminate veneershave become a large part of dental practice. Most ofwhat has been published regarding provisional treat-ment for veneers has focused on technical procedures.Provisional veneers are indicated when (1) esthetics andintelligible speech are important; (2) mandibular inci-sors are veneered; (3) dentin is exposed; (4) proximalcontacts are broken; (5) maxillary teeth are inverted lin-gually and the veneer surface affects occlusion; (6) thepreparation margin invades the gingival sulcus; and (7)the final veneer is dependent on patient approval of

form, color, contour, and position.171 Sheets172 statedthat patients were happier with provisional veneers butrecommended that provisional restorations not beluted. Provisional restorations allow patients to have atrial period for making notes about esthetics so that theirdesires can be taken into account with the definitiveveneer treatment.151 Provisional veneers may be ce-mented,151,173,174 bonded,23,151,171,174-176 or left un-luted.24,172

In contrast to preparations for conventional cast res-torations, preparations for porcelain veneers may nothave mechanical retentive features and thus one concernregarding a provisional restoration is tooth attachmentwhile avoiding irreversible contamination or alterationof the luting surface of a prepared tooth. Elledge174

advocated placing 2 small dimples on opposing surfacesof the preparation to provide mechanical retention forthe provisional veneer that is luted with a cement of theclinicians choice. One method that avoids excess ce-ment while sealing the margin area is the peripheral sealtechnique that uses a 3-second etch of the preparationperiphery and then bonding a provisional restorationprimarily at the etched periphery.171 Similarly, a coloredluting resin may facilitate removal of excess resin andreduce contamination of a tooth surface. After a provi-sional restoration is removed, 1 report indicated that atooth could be satisfactorily cleaned of all residues witha microetcher (Danville Engineering, San Ramon, Cal-if).177

Another technique known as the spot etch methodincorporates provisional restorations that are luted withlight polymerized acrylic resin to an etched spot near thecenter of the preparation.175 In an in vitro study ofsurface contamination associated with provisional bond-ing, a polyurethane isocyanate surface treatment left thecleanest tooth structure whereas a noneugenol provi-sional cement left significant but removable residue; adual polymerizing resin cement left tenacious residuethat could only be removed with a bur.124

A variety of methods for fabrication of veneer provi-sional restorations have been reported and are not unlikethe methods advocated for conventional provisional res-torations including, a removable splint,24 with hand-formed visible light-polymerized materials,23 polycar-bonate provisional crowns,173 acrylic resin shells,151 andsplinting together adjacent provisional veneers.176

Esthetics

Patients may be highly motivated by esthetics andinstant improvement can be achieved through provi-sional restorations.15 Custom colored provisional resto-rations made with mixtures of acrylic resin powders cre-ating an incisal polymer, a body polymer, and a cervicalblend are easier to fabricate with an indirect method.156

Esthetically enhanced provisional restorations can be

Fig. 3. Prevalence in literature of polymerizing methods fortooth-borne provisional restoration materials.


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fabricated with visible light-polymerized labial veneersor denture tooth facings in conjunction with acrylic res-in.5,44,138

Gingival architecture and tissue contour are amongthe many factors other than materials that influence es-thetics. Anterior provisional restorations should providethe following esthetic benefits: (1) optimum periodon-tal health; (2) visualization of the anticipated estheticoutcome; (3) ability to test the incisal edge position andcervical emergence; (4) development of appropriate an-terior guidance; and (5) determination of the need forperiodontal surgery.117

Methods for improving or customizing colors alsoinclude coloring provisional luting cements178 and col-oring a provisional restoration with porcelain stains andvisible light-polymerized acrylic resin.172 Custom colorguides for provisional restorations have also been rec-ommended.179-181

CLINICAL CONSIDERATIONS FORPROVISIONAL TREATMENTINVOLVING DENTAL IMPLANTS

Provisional prosthesis designs for dental implant pa-tients can vary widely, ranging from a removable acrylicresin complete denture, to an implant supported fixedprosthesis with several different potential designs thatpromote esthetics, convenience, the loading of im-plants, tissue contour control, material strength, andinterim prosthesis durability. Although several remov-able prosthodontic provisional treatment modalities areavailable in conjunction with implant treatment, thisdiscussion is primarily limited to fixed provisionalprosthodontic treatment and specific materials. Manu-facturers are indicated when available in the original ref-erence. Generally, the literature related to implant pro-

visionalization is dominated by anecdotal informationand clinical observation. Information related to implantfixed provisionalization is therefore limited and is gen-erally a carryover from natural tooth provisional treat-ment techniques.

A provisional restoration in combination with an im-plant-retained restoration provides many of the samebenefits derived when treating non-implant retainedfixed restorations. However, implant-retained treatmentcan require an extended period of time and provisionaltreatment can present a challenge. When the implant-retained prosthesis is located in an esthetic region, theneed and desire for an interim prosthesis increases. Inthis respect, the transition from tooth-related fixedprosthodontics to implant-retained prosthodontic treat-ment has evolved from experience with conventionaltreatment.182,183 Restorative techniques are often thesame, and management of a patient can simulate con-ventional fixed prosthodontic treatment. Nonetheless,the significance of provisionalization with implantprosthodontics cannot be overstated.184,185

Table VIII186-214 lists provisional fixed prosthodon-tic treatment options for an implant patient that mayvary depending on (1) the number, position, or locationof the implants; (2) the number of natural teeth remain-ing in a treatment arch; (3) opposing occlusion; (4)whether teeth adjacent to the implant site(s) can serve asabutment teeth for a provisional restoration; and (5) thedesired protocol for provisional treatment at either first-or second-stage surgery.

Historically, most endosseous implant systems haveused a 2-stage surgical procedure. The surgical stageswere separated by a 4- to 6-month period to allow fortissue integration. When necessary, a removable interimprosthesis was used. This protocol evolved from treat-

Table VIII. Interim treatment options for an implant prosthodontic patient

Treatment protocol Clinical conditions

No interim prosthesisrequired

Esthetics not a concern to a patient Implants placed in posterior region

Removable interimprosthesis

Before first-stage surgery;eliminated after first-stagesurgery with implant-supported provisional

Before or just after first-stage surgery;eliminated after second-stage surgery withimplant supportedprovisional

Before or just after first stage surgery, maintained untilcompletion of definitive treatment196,200202

Fixed interimprosthesis

Resin bonded using clinicalcrown of extracted toothor denture tooth203,204

Resin bonded ponticprosthesis186,189,208

Provisional fixed partialdenture with adjacentabutment teeth205208

Transitional implants/fixed prosthesisimplant retained214

Natural tooth abutment-retained cantilever fixedprovisional209

Transitional implants/fixedprosthesis implant toothabutment retained

Provisional placed at orshortly after first-stage surgery implantretained187,188,190195,197199

Fixed implant retainedprovisional placedafter second-stagesurgery/no removableprosthesis210,213



ment of an edentulous patient to treating a partiallyedentulous patient. The use of a removable provisionalprosthesis, however, in some situations has been lesspopular when treating a partially edentulous patient.Several factors have been proposed suggesting why thisprotocol has been challenged. When treating a partiallyedentulous patient, acceptance of a removable interimprosthesis may be objectionable and great lengths maybe taken to fabricate a fixed provisional restoration totransition a patient through the implant integration pe-riod.215

A reduction of micro-movement of an implant due tothe potential stability obtained from adjacent teeth aswell as a rigid implant connection when treating bothpartially and completely edentulous patients may lead tosuccesses when providing provisional treatment at first-stage surgery.187 As a result, early or rapid loading ofseveral implant systems has been tested, however, rou-tine immediate or rapid loading of dental implants is stillcontroversial. The use of transitional implants has alsobeen explored for support of a fixed implant-retainedprovisional prosthesis. Of course when the adjacentteeth can be used as abutments supporting a fixed in-terim restoration this treatment option may be moreeasily accommodated throughout the implant integra-tion time period.186

Single-tooth, implant provisional treatment

One of the most challenging restorative treatmentscenarios involves restoration of a single tooth im-plant.216 The demand for optimal esthetics and a naturalappearance to a definitive restoration dictates a compre-hensive diagnosis and treatment plan. Depending on thelocation of an implant, an interim prosthesis may or maynot be necessary. For example, providing a provisionalrestoration in the posterior region during the implantintegration period may be avoided if esthetic demandsfrom the patient are low. On the other hand, in anesthetic region, great lengths may be taken to replace theedentulous area with a provisional restoration therebyproviding a more socially acceptable interim treatmentbefore a definitive restoration.

Techniques related to replacing a single tooth with animplant prosthesis embrace both first and second stagesurgical protocols. Provisional treatment options arealso related to treatment history of the adjacent abut-ment teeth.189,192

Provisional treatment at first-stage surgery:single-tooth, implant-retained

The placement of interim implant-retained fixed res-torations at first-stage surgery provides benefits relatedto the time involved and the multi-step process in dentalimplant therapy,187 as a result, provisional fixed implant-supported restorations have gained in popularity. Fixed

implant-retained provisional treatment at first-stage sur-gery eliminates a removable interim prosthesis and theneed to involve adjacent natural teeth. Although manyreports advocate or explore this protocol, implant pro-visionalization techniques are, in most respects, a car-ryover from conventional natural tooth provisionaliza-tion. The literature is comprised of techniqueinformation with little or no scientific or evidence-basedinformation presented.

Several studies have questioned or evaluated the po-tential to restore an implant fixed prosthesis using earlieror more rapid occlusal loading, thereby incorporating afixed provisional restoration early in the implant restor-ative procedure.190,191 Kupeyan and May191 described atechnique in which the 2-stage Brnemark implant sys-tem (Nobel Biocare, Yorba Linda, Calif) was used in a1-stage, nonsubmerged surgical procedure with place-ment of an interim fixed single crown restoration atstage-1 surgery. The authors modified Brnemark heal-ing abutments (5.5 or 7.5 mm in length) in the labora-tory before the surgical date for the fabrication of pro-visional restorations. The authors also fabricated acrylicresin copings to fit the modified healing abutments, withan autopolymerizing acrylic resin (Jet Acrylic, LangDental Mfg. Co, Chicago, Ill) in the appropriate patientshade. A provisional crown was fabricated from either apolycarboxylate material or a polystyrene preformedprovisional shell that was filled with autopolymerizingmethylmethacrylate also of an appropriate shade. Aftersurgical implant placement, an interim restoration wasfabricated by fitting the resin coping to the modifiedimplant healing abutment and uniting the crown to thecoping with a small amount of autopolymerizing resin.The final finishing of the margins of the provisional wasaccomplished extraorally. The provisional restorationwas luted with a provisional cement (TempBond; KerrMfg Co, Romulus, Mich).

Chee and Donovan192 also described provisional re-storative treatment of a single implant-retained crown atboth first- and second-stage surgery. At second-stagesurgery, the authors advocated recontouring the softtissue cuff with a coarse diamond and placement of aprovisional restoration with ideal axial contours. Theyalso described fabrication of a provisional crown beforesecond-stage surgery with the technique described byHochwald217 in which an impression is made at first-stage surgery by use of the surgical guide. The resultantcast allowed fabrication of a provisional restoration be-fore uncovering the implant.

A technique for fabricating a provisional, screw-re-tained restoration for immediate loading of single im-plants was presented by Proussaefs and Lozada.218 Aprovisional restoration was fabricated for a maxillary firstpremolar extraorally during the surgical appointment.The usual preparatory phase of treatment was done be-fore the surgical procedure: (1) diagnostic casts; (2) di-


NOVEMBER 2003 489

agnostic waxing (Sculpturing Wax; Williams Co, Am-herst, Mass); (3) duplication of the diagnostic waxingwith an impression (Coe Alginate; GC America Inc,Alsip, Ill); and (4) generation of a gypsum cast (Micro-stone; Whip Mix Corp, Louisville, Ky). A vacuum-formed matrix (Ultradent Products Inc, South Jordan,Utah) was also fabricated. The authors fabricated a light-polymerized acrylic resin template (Triad; Dentsply Inter-national, York, Pa) on the duplicate cast that was used asa surgical guide during implant placement and also reg-istered the implant position at time of surgery by apply-ing autopolymerizing resin between the access hole ofthe template and the implant (Pattern Resin; GC Co,Tokyo, Japan). After polymerization, the template wasremoved, an implant analog was attached to the guide,and the template was positioned on the original diag-nostic cast that had been modified to allow placement ofthe implant analog. The analog was incorporated intothe cast with autopolymerizing acrylic resin (PatternResin; GC America). A temporary hexed abutment(Replace; Nobel Biocare) was placed on the implantanalog and, after verifying the appropriate occlusal heightand position of the abutment with a clear vacuumformed matrix, a screw-retained provisional was fabri-cated with the matrix and autopolymerizing acrylic resin(Alike; GC America). The provisional restoration wastrimmed in the laboratory and adjusted intraorally.Gomes et al219 also described this technique in whichthe provisional restoration was fabricated in the labora-tory before the surgical placement of the implant.

Provisional treatment at first-stage surgery:partially edentulous and edentulous, implantretained

Published reports have advocated immediate loadingof multiple implants in an edentulous or partially eden-tulous patient to avoid a removable interim prosthe-sis.193-197 In most articles, authors did not describe thematerial and methods involved with provisional fabrica-tion therefore details are limited.

Horiuchi et al193 reported the immediate loading ofBrnemark implants after placement in edentulous pa-tients and treatment with fixed interim restorations. Theauthors fabricated heat-polymerized acrylic resin provi-sional restorations reinforced with chromium-cobaltcastings. At the time of stage-1 surgery, implants wereimmediately loaded and incorporated within the provi-sional restoration using temporary cylinders. Jaffin etal195 also evaluated the immediate loading of implants inpartially and completely edentulous patients. Rigid fix-ation and the use of a metal-reinforced, passively fittingprovisional restoration were factors proposed for suc-cessful use of this protocol.

Kinsel and Lamb198 described gingival esthetics re-lated to treatment of an edentulous patient with an im-

mediately loaded single-stage, implant-supported fixedprosthesis. The authors fabricated heat-polymerizedacrylic resin provisional restorations from diagnosticcasts. These provisional restorations were relined in-traorally at the time of implant placement. The authorsalso described treatment in which retention from suffi-cient teeth to support a transitional fixed prosthesis andovate pontics were created within the extraction sites tobe used to maintain facial prominence and interdentalpapillae surrounding the extracted teeth. After implantintegration, the remaining abutment teeth were ex-tracted, and the provisional prosthesis was converted toa solely implant-supported provisional prosthesis.

In a preliminary report, Balshi and Wolfinger199 eval-uated the immediate loading of Brnemark implantsplaced in the mandibular arches of 10 edentulous pa-tients. The design involved 4 widely distributed im-plants that were immediately loaded with an interim,fixed, implant-retained prosthesis at first-stage surgery.The authors used additional implants in a conventionalmanner to provide sufficient support for a definitivefixed prosthesis, even if all the immediately loaded im-plants failed.

The use of 2-stage threaded implants to support animmediate, fixed, interim prosthesis was also outlined bySchnitmann et al.197 The authors converted a previouslyfabricated complete denture into a fixed-retained provi-sional partial denture by incorporating gold cylinders(Nobelpharma USA, Inc, Chicago, Ill) in the completedenture with autopolymerizing acrylic resin (Jet Acrylic;Lang Dental Mfg). The complete denture containingthe gold cylinders (1 anterior, 2 posterior) was recon-toured into a fixed partial denture by removal of theflanges and reduction of the distal extension to within 2mm of the posterior screw holes. After securing to theabutments with gold screws (Nobelpharma, USA, Inc),the screw channels were filled with cotton pellets andCavit (ESPE, Bad Seefeld, Germany).

Balshi and Wolfinger200 also described the conver-sion prosthesis, one that at second-stage surgery wasconverted from a complete denture to a fixed, interimprosthesis. The technique involved incorporation ofmodified screw-retained impression copings (as op-posed to more costly gold cylinders) within a wire-rein-forced complete denture. Advantages suggested by theauthors were as follow: (1) a fixed prosthesis with im-proved function, stability, and distribution of load wasprovided immediately following second-stage surgery;(2) the prosthesis protected the mucosa; (3) it served asa prototype for a definitive prosthesis; (4) it could beused as a verification jig; (5) the original vertical di-mension of occlusion was preserved; (6) the provi-sional restoration aided in obtaining and transferringinterocclusal records; and (7) it assisted long-termpatient maintenance and reduced the number of treat-ment visits.



Cibirka and Linebaugh201 described modification ofan existing conventional complete denture to a fixed/detachable interim prosthesis 10 to 14 days after second-stage surgery. The authors modified an existing mandib-ular complete denture by attaching Brnemarktemporary cylinders (Nobel Biocare) with an autopo-lymerizing acrylic resin using a closed-mouth technique.Once polymerization was complete and the fit verified,the denture base flanges were modified with the provi-sional prosthesis removed to resemble the definitiveprosthesis. After polishing, the prosthesis was attachedto the transmucosal abutments and the screw accessholes were sealed with Cavit (ESPE). The authors sug-gested advantages of this interim treatment techniquestating that the procedure was accomplished in 1 ap-pointment, it was convenient for a patient, and the pros-thesis served as a template for a definitive prosthesis.Berglin202 also presented conversion of a patients exist-ing complete denture by fitting gold cylinders to a pros-thesis (DCA-072 or 073; Nobelpharma USA, Inc) withacrylic resin (Coe-rect; Coe Laboratories).

Aparicio220 outlined the importance of passively fit-ting provisional implant-retained prostheses in a techni-cal report. He emphasized that interim treatment offersthe possibility of evaluating or creating the following:(1) a proper emergence profile; (2) peri-implant health;(3) occlusion; and (4) esthetics, phonetics, and hygiene.This also facilitates progressive loading of implants dur-ing the bone maturation period. Modified gold cylin-ders for EsthetiCone abutments (Nobel Biocare) wereused so that a provisional prosthesis could be luted tothe cylinders in the mouth with a provisional luting ce-ment (Kulzer Microfilm Pontic Cement; Heraeus Kul-zer, Wehrheim, Germany). This provided a circumfer-ential fit between the prosthesis and gold cylinders andeasy retrievability.

Tooth-retained provisional treatment at orbefore first-stage surgery

When teeth adjacent to an implant are not to berestored with a fixed prosthesis, a resin-bonded fixedpartial denture (RBFPD) may provide an interim treat-ment option, avoiding or eliminating a removable pros-thesis.203 Breeding and Dixon189 described the fabrica-tion and use of a resin-bonded prosthesis withorthodontic retainers (Bond-A-Splint; TP Orthodon-tics, Inc, La Port, Ind) and a light-polymerizing restor-ative material (Triad VLC Provisional Material;Dentsply). After surgery, the interim prosthesis isbonded to adjacent n

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