The incidence of root caries in theadult periodontal patient isincreased by a number of fac-

tors, including gingival recession, diet,poor oral hygiene, periodontal disease,xerostomia produced by many commonmedications, Sjogren’s disease, chemo-therapy and radiation treatment.

Diagnosing, treating and avoidingroot fractures present some of the most

The Root of the Problem:Root Caries, Fractures andSensitivity in the AdultPeriodontal Patient

From Our Officeto Yours...

Along with the increase in the popula-tion over the age of 62 who are keepingtheir natural teeth longer has come anincrease in the prevalence of root caries,root fractures and root sensitivity.

This newsletter reviews current trendsin the prevention, diagnosis, treatmentand management of these growing rootproblems.

As always, we welcome your ques-tions and comments in our collaborationto manage these common conditions.

Your practice is very important tous. It is always our goal to partnerclosely with you to support yourpractice, strengthen our professionalrelationship and increase the effec-tiveness of our teamwork.

We hope this newsletter is a valu-able source of information which youhave been able to integrate into yourpractice.

We thank you for your referralsand as always, when you refer apatient to us, we do our utmost tolive up to the confidence you haveplaced in us.

challenging restorative problems todentists.

Moderate tooth root sensitivityreportedly affects ten percent of thegeneral dental population.

Consequently, developing effectivetreatment regimens for managing thesevexing problems could benefit many ofour patients.

Figure 1. Rootcaries caused theloss of this postand crown andnecessitated theremoval of thetooth.

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The Brown

I. Stephen Brown, D. D. S., Periodontics & Implant Dentistry

I. Stephen Brown, D. D. S. 220 South 16th Street, Suite 300 • Philadelphia, PA 19102 • (215) 735-3660

Resin-modified glass ionomers are use-ful since they bond to tooth structure, areesthetic and possess long-term fluoriderelease which can be replenished with top-ical fluoride applications.

Dentin bonding agents which incorpo-rate antibacterial activity into their sys-tems are also useful in inhibiting rootcaries.

Diagnosing, Treating and

AvoidingRoot Fractures

Teeth seem to fracture for two primaryreasons: occlusal forces (chewing andparafunctional) which sometimes over-load natural teeth, and fractures secondaryto brittle roots due to endodontic treatmentor large post spaces.

Trauma, such as chewing ice, biting intoa cherry pit or bruxism may also con-tribute to fractures. These fractures oftenoccur around existing restorations. Someof them can be treated with periodontalsurgery to crown lengthen the involvedtooth, thus exposing the fracture marginfor restorative care.

Today, CT scanning makes it possible todiagnose some vertical root fractures notvisible with conventional radiography.

These fractures can also be diagnosedby illuminating the inside of the tooth.

Root Caries Root surface caries, like other types of

dental caries, results from the interactionof a triad of factors, namely bacterialplaque, dietary carbohydrates and sus-ceptible tooth surface.

Numerous microbiologic studies haveidentified the culprit bacteria asStreptococci Mutans and Lactobacillus.

Salivary gland dysfunction, leading toreduced salivary output, contributes toincreased susceptibility to root caries byremoving the buffering effects of thesaliva and by decreasing the amount ofmineral available for remineralization.

Dry mouth is most often produced bymany commonly prescribed medications,chemotherapy and radiation treatment.

PreventingRoot Caries

Simple prevention techniques like theuse of fluoride appear to be quite effec-tive in preventing root caries as well asarresting their development.

Chlorhexidine and especially fluoridevarnishes are important tools for the pre-vention and chemotherapeutic treatmentof root caries.

Preventive care can include: a fluo-ride dentifrice; annual bitewing radi-ographs (vertical bitewings if signifi-cant alveolar bone loss is present); quar-terly to semiannual recall; fluoride var-

nish; application of topical, high con-centration fluoride; daily fluoride rinse,fluoride gel 1.1% (neutral NaF) in trays;home care instruction; dietary counsel-ing; bioactive glass or calcium phos-phate containing pastes and antimicro-bial therapy with or without monitoringM. streptococcus levels.

DiagnosingCarious Lesions

Because root caries are so aggressiveand develop so quickly, general dentists,hygienists and periodontists need towork together closely.

Examination strategies should focuson those patients with known risk factorspaying special attention to proximal sur-faces.

Vertical bitewing radiographs are anexcellent clinical examination becausethey permit better evaluation of theentire interproximal root surfaces.

Intraoral radiographs may not alwaysbe reliable because of “burn out” whichmay occur at the cementoenamel junc-tion seriously obscuring the radiograph-ic evidence of early decay.

Treating Root Caries

Fluoride-releasing materials and metalions contained in glass ionomer restora-tive materials may inhibit recurrent cariesin restored root surfaces.

Figure 2. Subgingival root decaycaused the loss of the existingprosthesis.

Figure 3. Crown lengtheningwas performed to assist in theconstruction of a new restoration.

Figure 4. The final restorationthree months post-op.

PerioDontaLetter, Spring

Additional diagnostic information isgained from periodontal probing of thearea. A vertical fracture will often share avery narrow and very deep pocket depth atthe fracture site.

Root fractures are usually untreatableand these teeth are usually lost.

Root Fracture inEndodontically-Treated Teeth

Computer modeling studies indicate thatperiodontal bone loss increases the likeli-hood of root fracture in endodontically-treated teeth with posts. In these teeth,stress is concentrated at the apical end of thepost and in the dentin lateral to this region.

The stress is higher and more concen-trated in teeth with reduced periodontalsupport. It appears that fracture may berelated to the decrease in dentin widthnear the end of the endodontic post.

For many years the rationale for the useof posts was not only to increase crownretention, but also to protect the toothfrom fracture resulting from internalstress. Now studies show that endodonti-cally-treated teeth without posts tend tofracture less than post-treated teeth andthat it is the bulk of dentin in the region ofthe apex of the post that is most importantin preventing fractures.

The amount of remaining supragingivaltooth structure supporting the crown andpost is also very important.

Some observers have also noted thatendodontically-treated teeth without poststend to fracture in a repairable mannerwhile post crowns tend to experience totalroot fracture. Again, sufficient dentin atthe apex of the post reduces the likelihoodof these fractures. In fact, when there isadequate clinical crown length for castcrowns, retention posts are not necessary.In many cases, periodontal surgical crownlengthening can increase crown length,thus eliminating the need for posts.

Another potential problem with postplacement is the perforation of the rootsurface wall during post space prepara-tion. This occurs most frequently in situ-ations of long post preparation in thin,tapering roots or on roots which have pro-nounced figure eight interproximal con-cavities not apparent on radiographs. The

root anatomy of mandibular molar roots,mesial roots of maxillary molars and theroots of maxillary first premolars oftenhave pronounced concavities with thecanal space close to the inner aspect of theroots. This makes these teeth question-able candidates for post placement due tothe high risk of root fracture.

Root SensitivityRoot sensitivity is usually the result of

fluid shifts within the dentinal tubulesinduced by thermal changes or chemicalgradients which stimulate free nerve end-ings in the pulpal tissues.

Causes of root sensitivity include injuryto the dentin, gingival recession and acidproduced by bacterial plaque.

Figure 5. The upper rightsecond bicuspid was previouslyrestored with a post and crownand is tender upon chewing.

Figure 6. The initial radiographdoes not reveal the cause of thepatient’s symptoms.

Figure 7. Flap reflection revealsa mesial vertical root fracture ontooth #4 which caused thetenderness on mastication. Thetooth prognosis was hopeless.

Figure 8. Verticalroot fracture in anendodontically-treated tooth withcomplete loss of thebuccal bone plate.

Defective and leaking restorations,excessive occlusal loading, some tartarcontrol toothpastes as well as toothwhitening agents and dietary acids havealso been implicated.

All of these conditions reduce ordestroy a “smear layer” of debris whichoccludes portions of the dentinal tubulesand demineralizes tooth structure.

Prevention of sensitivity by reducing itscauses includes:

1. Improved supragingival plaquecontrol

2. Occlusal correction of teeth intraumatic occlusion

3. Dietary and/or dentifrice changes toreduce smear layer loss

4. Replacing restorations with defectivemargins

5. Endodontic care for teeth withpersistent pulpal irritation

Experience has shown that root sensi-tivity increases or decreases in direct pro-portion to the amount of acidic foodsingested.

Essential to diagnosing root sensitivityis both a careful history and thoroughexamination, including radiographs.Typically, the patient can readily identi-fy the sensitive tooth or teeth and candescribe the stimulus that initiates thepain. Exposed dentin is normally appar-ent as is loss of gingiva.

The examination must exclude the pres-ence of dental caries and pulpal pathology,vertical cracks and cracked cusps, andleaking restorations. Touching the expo-sed dentin with an explorer, or a spray ofcold air from the air-water syringe afterisolating the suspected tooth will helpconfirm both the diagnosis and the area inneed of treatment.

Managing andTreating

Root Sensitivity

The objectives of treating root sensitiv-ity are two fold: reduce the factors whichheighten sensitivity and occlude dentaltubules.

While desensitizing toothpaste mostoften manages mild tooth sensitivity, theseagents require prolonged use before theyare effective.

However, when patients report initiallymoderate or persistent root sensitivity, thecauses should be examined further andpossible secondary causes treated. Ifnone of those factors is determined to playa major role, tubule-occluding treatmentshould be recommended.

Seven agents which occlude dentinaltubules have proven successful:

1. Fluorides. A 0.717 percentstannous fluoride solution can beapplied in the office followed bythe patient’s daily use of 0.4 percentstannous fluoride gel. Sodiumfluoride should be substituted athome if staining of stannous fluorideon restorative materials is apossibility. A fluoride varnish(Duraphat, Colgate Corporation) canbe used as the in-office treatment.Duraphat is easy to apply with asmall brush and saliva contaminationis generally not a concern.

2. Oxalates. Potassium oxalate(Protect by Butler and Therma-Trolby American Dental Hygienics) and Ferric Oxalate (Sensodyne Sealant by Block Drug) deposit respectivelypotassium and iron precipitateswhich seal the dentinal tubules.

3. Root coverage. Isolated areas of root exposure with sensitivity maybe candidates for root coverage withgingival graft surgery. This willalso alleviate any cosmetic concernscaused by the recession.

4. Dentin bonding agents. Resin-based adhesive systems can providea more durable and long lastingdentin desensitizing effect. Theyseal the dentinal tubules and modifythe smear layer, incorporating it intoa hybrid layer. Clinical trials haveshown All Bond, Scotchbond,Gluma, Amalgambond, Pain Free,Root Surface Dentin DesensitizationKit by Bisco and Prime & Bond allproduce good results.

5. Bioglass. A formulation of bioglass in a dentrifice can promoteinfiltration and remineralization ofdentinal tubules The bioactive glass converts to hydroxycarbonatedappatite through the formation of asurface silica gel layer. Thismineralizing surface bonds to and"seals off" the open tubule, therebyreducing the sensitivity. Twocommercially available products areRenew and Oravive.

6. Casein (phosphopeptide-amorphous calcium phosphate). Recently, milkprotein casein has been used todevelop a remineralizing agent (GC Tooth Mousse) which may help inthe prevention and treatment ofdental hypersensitivity. Clinpro5000 and MI paste which combinesodium fluoride with tricalciumphosphate are also available.

7. Depolarizing Agents. Depolarizing agents are basically potassiumnitrate-containing products that desensitize by compromising thenerve’s ability to transmit the painful response through depolarization of the nerve. These agents includeproducts such as Ultradent and Relief ACP.

While the choice of approach is up tothe individual clinician, treating rootsensitivity beyond recommending a den-tifrice offers a valuable service to thosepatients who experience moderate orsevere sensitivity.

Since sensitivity is so subjective, theidentification of causative factors and iso-lation and identification of sensitive areasis essential to developing a treatment reg-imen for managing sensitivity.

While not always successful, establish-ing a diagnostic regimen and a reasonablypredictable treatment protocol will help toidentify the causes of these difficult situa-tions and ultimately benefit your patientsby reducing unpleasant symptoms.

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I. Stephen Brown, D. D. S. 220 South 16th Street, Suite 300 • Philadelphia, PA 19102 • (215) 735-3660