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Resin-lonomer and Hybrid-lonomerCements: Part II. Human Clinical andHistologie Wound Healing Responsesin Specific Periodontal Lesions

Mick R. Dragoo '

Twent/-ñve subjects yyitti a totoi of 50 subgingivai restorations participatedin this study. At tt^e beginning ot ttie investigation, nine teeth that were con-sidered iiopeless because of the extent cf tiieir pathaiogy were selectedfor extraction to evaluate histotogicoiiy the restarations and tiieir effect onthe adjacent tissues. The purpase of this orticie is to demanstrate theresponses to the clinical appiicatians as yyeil as to the placement of resin-ionomers in subgingivai iesians. Clinical and histologie evidence ot epithe-lial and cannective tissue adherence to resin-ioncmer restarative materiaiswas observed during the heaiing process. (Int J Periodont Rost Dent1997:17:75-87,)

"Visiting Professor, Universify of Nebraska, Lincoln, Nebrasi<a: andVisiting Professar, Universify of Washington, Seattle, Wostiington,

Reprint requests: Dr Mick iî. Dragoo. 101Ó7 Quoil View Drive,Escondido, Calitornia 92026,

Recently, modified resin-gioss-ionomer formulotions wereplaced OS subgingivai restora-tive moteriols to restore teeththat were previously consideredhopeiess and/or nonrestor-obie.' Root iesions that requiresubgingivoi restorations mayinoiude cases invoiving rootrésorption, fractured roots, ero-sive lesions, endodontic perfora-tions, and deep carious rootlesions. Port i of this seriesdesoribed the ideoi charocter-istics, occording to the author,of o subgingivai restorativematerial for the repair of suchdefects, as well as fhe differ-ences between several restora-tive materiais that ore poten-tially suitable for this purpose. Todelineate and more corefuliydefine the wound heoiingresponses ot the periodontiumfoilowing these subgingivoirestorative procedures, clinicaland histologio evidence ofrepair of fhe periodontal com-piex is necessary,^ Therefore,the purpose of this articieis to describe the ciinicai

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opplications and placement cfresin-ionomer restorative mate-riais in subgingival iesions andto present the histoiogic woundhealing that follows these thera-peutic procedures.

Method and materials

Twenty-five subjects in need ofa total of 50 restorations partici-pated in this study All subjectswere intormed of their orai con-dition, and all received a thor-ough oroi and written explana-tion of the procedures to bepertormed. Atter a subjectreceived this information andbetöre the procedure wasstarted, an informed consentdocument was signed. Clinicaldocumentation inciuded acomplete-mouth periodontaichart, radiographs. 35-mmcoior siides, assessment of gin-gival inflammation based onthe presence or absence ofredness and bieeding on prob-ing, ond the measurement ot aPlaque index.'̂ '

Measurement ot probingdepth was made paraliel tothe long axis of the tooth with aspecialiy fabricated pressure-sensitive probe caiibrated to 10g of torce. Aii probing measure-ments were rounded off to thenearest miilimeter. Bleeding onprobing was assessed as eitherpresent (+) or absent (-) within30 seconds after probing ((+) =1, (-) = 0). Redness of the gin-giva was assessed as either

present (+) or absent (-) ((+) =1, (-) = D). Gingivai recessionwas measured from thecementoenamei junction (CEJ)and/or other fixed referencepoints that were available.Change in attachment levelwas determined from thechonges in probing depth, andgingivai recession measure-ments were taken at baseiineand postoperatively Ail mea-surements were rounded off tothe nearest millimeter

Preoperative preparationconsisted of scaling and polish-ing, as well as instruction in theBass method of tooth brushing,the use of unwaxed dental tloss,and the Perio-aid (Butler). Aperiod ot 4 weei<s was aiiowedfor patients to develop skills inpiaque removai before theexpérimentai procedures com-menced. It should be notedthat although the subjectsachieved Plaque Index scoresof one or beiow at the end otthis period, tew subjects main-tained that level for the durationof the investigation.

Two resin-ionomer restorativematerials, Dyract (restorative A,DeTrey/Dentsply) and Geristore(restorative B, DenMat), andone hybrid-ionomer material,Photao-Fil (restorative C, ESPEPremier) were used to restorethe dental iesions, Ali materiaiswere used according to theirmanufacturer's instructions,Sinoe aii of the dental lesionsin these investigations weresubgingivai, a fuii-thickness

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mucoperiosteal flap was re-tiected prior to restoration of thelesion. To control the hemor-rhage from fhe periadontal liga-ment and alveolar bone, a 30%hydrogen peroxide solution ono cotton pellet was applied tothe surgical site for 5 seconds toachieve hemostasis. An alterna-tive method would have beento use the Stabident System(Fairfax Dentai) with a localonesthetic containing a vaso-constrictor. This technique wasdesigned to allow local anes-thetic to be injected directlyinto the alveolar process vyithresuiting vasoconstriction andonesthesia. Once the restora-tions were in place, they werefinished with a fine-grit diamondonly, and no attempt was madeto polish the restored surtaoe.When the subgingival lesionhad invaded the puip oanal,the pulp was extirpated ond ogutta peroha point was placedinto the root canals to maintainthe patency of the canal priorto the placement of the re-storative materiai. The rootcanal fillings were completedsubsequent to the subgingivalrestoration.

The mucoperiosteal flapswere replaced and suturedwith a 4-0 silk suture, A perio-dontal dressing (Coe-Pack, GCAmerica) vyas piaced for thetirst postoperative week. Noontibiotics were prescribed or

administered. The use of ontimi-crobial mauth rinses was op-tionai otter the first week.Subjects were recolied weeklyfor the tirst 4 weeks, and thenon a monthly basis for the firstpostoperative year, and every 3months thereafter tor an assess-ment of periodontal condition.

Prior to performing therestorative procedures, a totalof nine teeth that had beendiagnosed as hopeiess by thepatients' dentists were seiectedfor extraction to undergo histo-logie evaluation. AM of thepatients selected for the histo-logie part of fhese studies wereimmediate denture patientswho were referred by their gen-eral dentists. Ot the nine teeth,three teeth were seieoted fortreatment with each product.At the end of 3 months, theserestored teeth with adjacenttissues were removed vyith theridge-preserving techniquepreviously described to histoio-gioally evaluate restoration-tooth-tissue interfaces.2 Thebiopsies were fixed in 7D% alco-hol and embedded in methyimethacrylate for microscopioexamination. Serial sectionswere out at 10 to 15 pm, andevery tenth section was stainedwith either hematoxyiin andeosin, toludine biue, or mineral-ized bone stain (MIBS), Allstained sections were studiedunder the light microscope.

Clinical case reports

Representative case reportsfrom the 25 subjects ond 50restorations evaluated for thisstudy are presented below.

External raot résorption

Externol resorptive lesions wereciassified by Mesaros andWayman^ according to the fol-lowing etioiogy: perlapicalinflammation, reimplontatian oiteeth, tumors and oysts, trauma,impootion of teeth, and idio-pathic conditions. The followingtwo cases are descriptive of thephysioiogic resorptive processthat tokes ploce as a result otinflammatory résorption.^ Thesecases may be charaoterized byintense inflammation with areasof bovyl-shaped résorption ofthe cementum and dentin.

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Fig la (ieft) Clinical photographdepiofing the exfent of the destructionof the roat and crown, r/ie root wasdestroyed approximately 2 mm apicalta the alveaiar crest.

Fig Ib(ieft) Clinioaiphotograph affhe root and crown restored wift^ aresin-ionamer restarafive material. Therestarafive materiai was piacedapproximately 2 mm subcresfal. and anew bone-resforation space had fo becreated with a thin, fine-grif diamand.

Fig fc(tignt) Radiogioph faken 1.5yeors pastaperative.

Fig ¡d Clinical phatagraph taken 1.5 years postoperative. Note the lack of gingivalinflammation adjooent fa the resin-ionomer material and triat the dihicai crownand roof were restored with the resin-ionamer material oniy. The toath ñas been infuncfion wifhout a past-and-care buiid-up and a crown lesforation.

Case I

A 31-year-old man presentedvi/ith a root resorptive lesion onthe lingual surface of his canine.Radiographic evidence andsurgical exposure revealed thatthe iesion extended approxi-mateiy 2,0 mm apicai to thealveolar crest. An endcdanticaccess opening was madein the croyi/n, and the puipvyas extirpated, A fuii-fhicknessmucoperiosteai tlap was re-

jected to expose the resarptivelesioh in the root surfoce. Around carbide bur v/as used toestabiish a solid tooth surface toreceive the restoration (Fig la).A gutta-percha point waspiaced in the root canal tokeep the canal accessible forthe projected endodontic pro-cedure. The restorative materialvi/as piaced approximately 2mm subcrestai ta inciude theentire resorptive lesion (Fig Ib).A thin, fine-grit diamond was

used to create a restoration-bone space and finish the mar-gin cf the restoration. The flapwas replaced. At 1,5 years post-operative, the tissue appearedciinicaily healthy and welladapted to the root surface(Figs Ic and Id). No rednessand/or bleeding on probingwas present. Probing assessmentdemonstrated minimai sulousdepth, which suggested tissueattachment fo fhe resforation.

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Case 2

A 41-year-old woman pre-sented with a root resorptivelesion on the iabial surface ofher anterior tooth, A flap wasreflected, and a lingual accessopening was made in thecrown to extirpate the pulp. Agutta-percha point was placedin the root canal to preserveand maintain patency of theroot canal tor endodontic ther-apy (Fig 2a). The resin-ionomerrestorative material was thenpiaced to restore the lesion inthe root (Fig 2b). The restorationwas finished with a fine-grit dia-mond, and the fiap wassutured coronai to the aiveoiarcrest (Fig 2c). At the end of 1year a noticeabie iack of gingi-val infiammation and minimalsulcus depth were apparentadjacent to the resin-ionomermateriai (Fig 2d),

Fig 2Q Clinical photograph depictingmot résorption destruction of the facialroot surface. Note the gutta-perchapoint In the root canal to maintaincanal patency. The root canoi woscompieted subsequent to sealing ofthe root surface wifh the resin-ionomerrestorative material.

Fig 2b Ciinicol photograph iliustratingthe resin-ionamer restoration In the rootresorptive iesian. The restoration wos fih-ished with a fihe-grit diamond bur

Fig 2c Clinioai photograph of the tis-sue flap sutured over the resin-ionomer.Note the distance between the CEJand ftie coronoi edge of the flap.

Fig 2d Clinicai photograph taken Iyear postoperative. Note the shaiiowsuiculor depth. taci< of gingivai infiam-mation, and change in flap positionover the resin-ionomer restoration whencompared to Fig 2c.

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fig 3a Clinical photogroph depictingmassive destruction of oiveoiar boneond a spat root (orrow).

Fig 3b Ciinicai photograph lilusrrofingthe apex (retrofil) and laPiai split rootrestored with a lesin-ionomer material.The surtoce of the restorative moterioiwas anished with a fine-grit diamond bur.

fig 3c Fignteen-month postoperativephotograph depicting a shaiiow gingi-val sulcus adjacent to the restored roofsurface.

Root fracture

Acute or chronic trauma mayresult in verficai crown and rootfractures. The defect moy be apartiol or complete fractureinvolving the crown and/orroot." Froctures have frequentlybeen associated with extensivedentai treatment. The followingcase describes a verticol frac-ture repoir.

Case 3

A 52-year-old womon pre-sented for periodontal treot-ment on a mandibular caninewith a deep pocket and iabioifisfula, Ciiniooi probing reveoled

extensive pocket formationmesiofacioiiy. Radiographie evi-dence indicated that the toothhad been endodonticaliytreated. Upon reflection of fhefissue, it wos noted thot theiobial root was fractured verti-cally (Fig 3a), The fracturedarea ond the opical foramen ofthe root conal were restoredwith o resin-ionomer materioi(Fig 3b), Eighteen months post-operative a shallow gingivoi sui-cus adjacent to the restoredroot surface was noted, and thelabial fistuia was no longer pre-sent (Fig 3c). The tissue was notinflamed, oithough piaquecould be observed ot the gingi-val morgin.

Restoration af caries underexisting crawns

Cories may occur at or apicalto the morgin of a single crownand/or bridge abutment.Usuoily the treatment of choiceis to remove the orown ond/orbridge, restore the cories (possi-bly preform a periodonfal surgi-cal crown iengthening proce-dure) and replace the crownand/or bridge. The aforemen-tioned can be o costly dentaloption for the patient. Advance-ment in odhesive dentistry andstudies on the biocompatibilityof resin-ionomer moteriols connow offer the patient a morecost-effective aiternative.

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Case 4

A 48-year-oid man presentedwith deep caries under a crown,a furcation invoivement, and anecrotic pulp on a right man-dibuiar right first moiar. Themoiar was the distal abutmentfor a three-unit bridge. Thepatient couid not atford to havethe bridge replaced, but didconsent to having endodontictreotment and a resin-ionomerrestoration placed to restore thecarious iesion. Since certainresin-ionomer cements bond toboth gold and dentin, this treat-ment concept seemed iike areasonabie alternative. Subse-quent to endodontic therapy, atull-thici<ness flap was reflectedto expose the e>rfent of the cari-ous lesion (Fig 4a). The carieswas removed, and a resin-ionomer restoration was piacedon the root and under thecrown. The tiap was replaced toits former position and sutured.Figure 4b demonstrates that thegingival complex ond the exist-ing bridge has respanded favor-ably for 3 years with no signs ofrecurrent caries, periodontaiinfiammation, or separation ofthe restoration from the goidcrown.

Histologie case reports

[Representative case reportstrom the nine histoiogic tissuespecimens evaluated far thisstudy are presented beiow.

Fig4a Ciinicai phofogtaph of amondibular righf firsf molar bridge olDuf-menf depicting roof cones ond o furca-fion invoivemenf.

Root perforafion

Unfortunately, iatrogenio injuriessuch as root perforotions duringendodontic procedures and/orpreparation for post-ond-corebuiid-up may occur in ciinicaiproctice even with diiigentcare. The toiiowing casedepicts a simuiated root perfo-ration that was repaired with aresin-ionomer restoration.

Case 5

Atter flap retiection, a root perfo-ration was simulated on theiabiai surtace of a central incisorof a 55-year-old man, who wasscheduied tor an immediate

Fig 4b Three-yeor posfopetotive ciini-coi photograph iiiustrofing fhe favor-abie response of fhe crown and gingi-vai compiex fo fhe resin-ionomerresf orof ion wifh no signs of breakdown.

denture by his gênerai dentist.The endodontic prooedure woscompleted prior to tissue reflec-tion. A resin-ionomer restorationwos pioced on the labiol sur-face of the tooth to repoir theiesion, finished with a tine-gritdiamond, and the tissue wassutured into piace. Three monthslater, during the placement otthe immediate denture, thelabial aspect of the tooth andadjacent tissue was taken torhistoiogic assessment. Histoio-gicaliy it was apparent that thetissue was adherent to the resin-ionomer used to repair the rootperforation (Figs 5a and 5b).

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Fig 5a Ciinicai photograph of a cen-frai incisar wifh a simulated roat lesionthaf cauld have been created by anendadontic post peroration, acciden-tal endodantic perforation, or a refrotiiendodonfic procedure. The perforationwas restared wifh a resin-ionamer mafe-rial to evoluafe fhe wound healing.

Facial raaf restoration

Recent advances in restorativedentistry have ailowed faciallesions to be estheticaliyrestored, i-iowever. concernshave been raised when saft tis-sue coverage is also desired.The following case describesthe placement of a resin-ionomer restoration in such aiesian and the subsequentplacement of tissue aver therestorative material.

Fig 5b Micrograph snowing fne iibrob-lasts and connective fissue (CT) nexf fothe resin-ianomer restoration (Rl) indentin (D) and the absence of inflom-mafory cells.

Case Ó

A 46-year-oid woman who wasscheduled for the piacementof a maxillary denture by hergeneral dentist presented withsupragingival and subgingivalroot caries and sett tissue de-hiscences on the labiai surfacesof a iaferai incisor and first pre-moiar.The canine was missing. Aflap was reflected so the teethcould be adequately restoredwith a resin-ionomer restoration(Fig óa). After restoring the

teeth, the flap was positionedcoronaiiy to cover the entirerestored root surface. Threemonths postoperative, theprobing depths were shaliow,and gingival inflammation (ie,redness and/or bleeding onprobing) was not evident evenin the presence of bacterioipiaque (Fig 6b), The labiaiaspects ot the teeth and adja-cent tissues were removed forhistoiogic evaluation of the lat-eral incisor and first premoiarprior ta the extractions andpiocement at an immediatemaxillary denture by her gen-eral dentist. The histoiogic sec-tions of the lateral incisor andfirst premalar exhibited a meansoft tissue coverage over theresin-ionomer restoration of7.02 mm, which consisted of amean sulcus depfh of 1.07 mm,a mean epitheliai attachmentot 1.82 mm, and a mean con-nective tissue adhesion of 4.13mm. The histoiogic sectionsrevealed bacteriai plaqueadjacent to the gingivai sulcusand a iack of inflammatoryoelis adjacent to the piaqueand suicus (Fig óc). This iack ofinfiommatary ceils couid alsobe observed in high-powermicrographs of the junotionalepithelium adjacent to theresin-ionomer material (Fig ód).i-ligher-pawer micrographs illus-trate the close adhesion of thefibroblosts and connective tis-sue to the resin-ionamer restora-tion (Fig óe).

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fig 6a Clinioal pnofograph of a lafer-ai incisor ahd first premoior. Nate fheioblai root surfaces are restated with aresin-ianamer material (arrows).

Fig Ob Ciinicai phofograph of fig óo 3monfhs posfoperotive depicting softtissue coverage aver the resin-ianamermaterial piaced on the faciai rootiesions. Note fhe presehce ofbocfena!piaQue hear the matginai gingiva.

Fig 6c i\/iicrograph of a tissue biock ofthe the laterai ihcisar in Fig 6a takeh 3months postoperative. Note baoteriotplaque (F) on fhe resin-ionomerresfaration (RI) in the denfin (D) next fofhe shallow gingival sulcus (S), and therelative lock of ihftommotofy ceiis ih thegingival tissues adjacent ta the plaaueand sutous. (Original magnificatian x50)

Fig 6d (left) High-power micrographdepicting the ¡uhctionai epithelium {Jt)adjacent to the resin-ionomer restoro-fion (Ri), Note the tack of infiommatarycelts. (Origihai magnifioafioh x 250).

Fig 6e (right) Higher-power micro-.::raph depictihg fibrabiasfs (F) oncfcohnective fissue (CT) adjaceht ta fheresin-ionamer restarafioh (R\). (Ofiginaimagnificafion x 500.)

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Clinical discussion

The subgingivai lesions restoredin this study were traditionallyconsidered to be unrepairableby many dentists. Based on thetindings of this sfudy, subgingi-vai restorations may now beplaced in a more routine fash-ion, because the materialstested exhibited dentin bond-ing capabilities and biocom-patibiiity to surrounding tissues.

Resuits indicate that, exceptfor the nine predeterminedteeth that were extracted andthe four restorative A tiiiings thatdebonded, ali af the teethrestored subgingivqily continueto be in tunotion after periodsot 1 to 3 years. Although thepatients were required toobtain a Piaque index of 1 orbelow to begin the study, themean PI exoeeded this ievelsubsequent to the restorativeprooedures (Table 1), All of therestorqtive materials exhibitedfluoride release, which mayhave altered the nature afplaque surrounding fhe restora-tions. Gingival inflammation, asassessed by redness and/orbieeding on probing, was mini-mai after healing (Tabies 2 and3). Probing depths are iisted inTable 4. The mean gains inattachment ievei after 1 yearare indicated in Table 5,

Certain resin-ionomer restor-ative materiais possess proper-ties that are biocompatiblewith periodontai tissues. This bio-compatibility may be related tothe antimicrobial activity of thefluoride release of resin-ionomermaterials that affects the com-position of the bacterial plaqueand piaque biochemistry byaltering carbohydrate metabo-lism (see Fig 6o),^ All of thecases demonstrated minimalsigns of clinicai infiammation(redness and/or bleeding onprobing. Tables 2 and 3) in theheaiing areas, even in the pres-ence of plaque, it was interest-ing to note that olthough thepiaque score increased overthe postoperative course (Table1), gingival infiammation de-creased (Tables 2 and 3).

Postoperative gingival re-cession was minimai tor aliprocedures. At 1 year postoper-ative, the mean gingival reces-sion was 0.42 mm, Aiso at 1 yearpostoperative there were signiti-cant decreases in probingdepths and gain in attachmentwith ali three materials tested(Tables 4 and 5), Aithoughrestorqtive A had 0.51 mm moreprobing depth than material Band 0.59 mm more probingdepth than material C, therewere no significant differencesin the gain of sott tissue attach-ment values vt/ith any of themateriais tested. Further studywill repori on the ditterences inbiocompatibiiity to bone tissue.

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it was aiso interesting tonote the positive correlationbetween redness and bieedingon probing at 1 yeor postoper-otive (Tabies 2 and 3). Whenthe soft tissue was advancedcoronoily over restored subgin-givai lesions (ie, coronaliy posi-tioned flaps to cover exposedroot surfaces), the clinicai prob-ing depths were minimai andthe gingival tissues appearedto adhere to the repaired rootsurfaces (Table ó), Preoperativeond postoperative probingdepths were similar: however,the postoperative gain in ciini-coi attachment wos 4.25 ± 0.43him over preoperative volues.The postoperative chonge inmarginai gingiva (ooronol od-vanoement) was 4.00 ± 0.71mm,

Certoin restorative moteri-ois hove the ability to reduceond/or eiiminate the incidenceof microleakoge. The resin-ionomer restorotive moterioimay act as a seal to minimizeany internal or external bacter-ioi contaminaticn between therestorative margin on the toothond the surrounding tissues,thereby facilitating the heaithof the gingival complex.

Crown lengthening was notperformed in any of the ooseswhere the lesion extended toor below the crest of the bone.The teeth were restored to fullfunctionolity whiie maintoiningon esthetic result.

Table 1 Plaque Index (mean ± SD)

RestorotiveA B C

Preoperative 0,86 ± 0.353 mo 1.29 ±0.59ó mo 1.54 ±0.63l y 1.30 + 0.61

0.68 ± 0.471.09 ±0,511.05 ±0,51I.10±0.46

0,80 ± 0.401,60 ± 0,491,57 ± 0,491,29 ±0.70

Table 2 Gingival inflammation (mean ± SD)

RestorativeA C

PreoperativG 0.92 + 0,26 0.77 ± 0.42 0.90 ± 0,303 mo 0.29 + 0.45 0,09 ± 0,29 0,10 ± 0.306 mo O.ld + 0.35 0,05 ± 0.22 0.14 ± 0.351 y 0.08±0.27 0.05±0.22 0.14±0.35

Table 3 Bleeding on probing (mean + SD)

RestorativeA C

Preoperotive 0.92 ± 0.26 0.82 ± 0.39 0.90 ± 0,303 mo 0.36 ± 0,48 0,39 ± 0.47 0,40 ± 0.49ó mo 0.23 ±0.42 0.05 ±0.22 0.M±0.351 y 0.08 ± 0.27 0.05 ± 0.22 0.14 ± 0.35

Table 4 Probing depth (mean + SD)

RestorativeA C

Preoperative 6.14 ± 0.83 5,55 ± 0.75 5.10 ± 0.703 mo 3.07 ± 0.46 2.45 ± 0.66 2.20 ± 0.40ó mo 3.15 ± 0.53 2.58 ± 0,67 2.71 ± 0,451 y 3.30 ± 0.61 2.79 ± 0 83 2.71 ± 0.88

Table 5 Mean attachmentlevel gains after 1 year

MeanSD

A

2.140.74

RestorotiveB

2.270.79

U

2.200.75

SD = Sfandord aevicifion.

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Table 6 Clinical measurements for soft tissuecoverage over resin-ionomers

Mean SD

Preoperative probing depth 2.5 0.50Postoperative criange in marginal 4.0 0.71

gingiva (coronal ottacriment)3-month postoperative 2.25 0.43

probing dGpthAttachment level gain 4.25 0.43

SD = Standard deviation

Table 7 Histoiogic measurements of soft tissuecoverage over resin-ionomer ot 3 monthspostoperotive (mm)

Mean

Sulcus depthLength ot epittieiiai at attaohmentConnective tissue adhesion

1.071.824.13

Histologie discussion

Histoiogic findings suggest epi-theiium and connective tissueodherence to the resin-ionomerrestorative materials during thewound healing process. Casespresented in this report indicatethat it may be possible to re-store the junctionai epitheliumand connective tissue adhesionto resin-ionomer restorationsand deter crown lengtheningprocedures that may resuit inadverse esthetics and/or morecomplicated orai hygiene pro-cedures. With crown iengthen-ing procedures it is usually nec-essary to expose sufficient toothby the removal of bone toailow the restoration to beplaced without impingementon the bioiogic widfh.*-^ Table 7shows the mean values ot serialsections taken trom histoiogicbiopsy specimens.

it is interesting to note theoomparison of the ciinicai mea-surements (Table 6) and histoio-gic meosurements (Table 7). Thecombined histoiogic measure-ments of sulcus depth and epi-thelial attochment are 2.89 mm,and the clinicai probing depthwas 2.25 mm. The histoiogic con-nective adhesion was 4,13 mmcompared to the 4.25 mm clini-cal attachment gain. Additionaihistoiogic studies are warrantedto confirm the new attachmentand/or adhesion between theresin-ionomer restorative materi-ais and the periodontai tissuesnoted in this study.

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Conclusians References

1, The author suggests thatresin-ionomers need to pos-sess the following physicalcharacteristics to be used osan ideal subgingival restora-tive material; biooompati-bility, dual-cure set, odhe-siveness, fluoride releose,rodiopacity, compactness,surface hardness, insolubiiityin orai fluids, absence ofmicroieakage, low ooeffi-oient of thermal expansion,and iow cure shrinkage.

2, Epitheliai and connective tis-sue adhesion was observedduring the wound healingprocess with restoratives A, B,ondC.

3, The physical properties ofcertain resin-ionomer re-storotive materials ailowediost orown and root struc-tures to be replaced func-tionally and estheticaliy inpiqce of traditional orownlengthening, post-and-oorebuild-up, and complete-crown procedures.

Acknowledgments

The author would iike to sincereiy conveyhis oppreciation to Timothy Stoli, DDS forhis heip in the clinical evaluations, ond toKent Zimmerman, MD (clinicai, anatomic,and cytopothologist) for his expertise ininterpreting the histoiogic material. Ali theciinicoi ond histoiogic research present-ed in this paper was prlvateiy funded byDr Mick R. Dragoo; however, the restora-tive materials were donated by manu-facturer representatives.

1. Scherer W, Dragoo M. New subgin-gival restorative procedures withGeristore resin ionomer. PractPeriodont Aesthet 1995;(Jan/Feb):1-4.

2. Dragoo MR. Regeneration of thePeriodontal Attachment in Humans.New York, NY: Lea & Febiger 1981:7-18.

3. Mesaros AJ Jr, Woyman BE.Simultaneous apical and cervicaiidiopathic external root résorption.Gen Dent 1994:CJon/Feb):70-73.

4. Stewart GG. The defec t ion andtreatment of verticoi root fractures.JEndodont 1988:47-53.

5. Wiison AD, McLean JW. Glass-ionomer cemen l . Ch icago:Quintessence, 1988;125-127.

6. Dragoo MR, Wiiliams GB. Perio-dontai tissue reactions to restorotiveprocedures: Part i. Int J PeriodontRestDentl981;l:8-32.

7. Dragoo MR, Wiiliams GB. Perio-dontal tissue reactions to restorativeprocedures: Part II int J PeriodontRest Dent 1982:2:35-47.

8. Drogoo MR, Suilivon HC. A ciinicaiand histoiogicai evoiuotion of outo-genous iliac bone grafts in humans:Part i: Wound heaiing 2-8 months. JPeriodontol 1973:d4:10.

9. Silness J, Loe H. Periodontol diseasein pregnancy, li. Correiation be-tween oral hygiene and periodon-tai condition. Acto Odontoi Scand1964:22:121-135.

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