Restorative Dentistry

Occlusal caries: Diagnosis and noninvasive treatmentsRoberta Tarkany Basting'/Mônica Campos Serra, MS, ScD"

The diagnosis ot occiusai caries and the initiation of more effective treatment present a considerable chai-ienge. Caries not oniy has decreased in prevaience, but aiso has changed in pattern and in progressionbecause ot the increased use of fluorides. Correcf diagnosis is oruoiai. distinguishing iesions that can bearrested by noninvasive treatment from those ihat may justify restorative treatment. For incipient iesions, itis neoessary to improve the patient's home care preventive methods, lo apply tluoride or other prophyiac-tic agents, or even to seat fissures, preserving the maximum amount of sound tooth structure. This articlediscusses the diagnosis of oodusal caries and noninvasive treatments for the management of eariy caries.(Quintessence int 1999;30:174-178)

Key words: arrested iesicn. caries diagnosis, incipient lesion, noninvasive treatment, occlusai caries

CLINICAL RELEVANCE: Precise diagnostic methods areimportant for deciding whether to treat a parficuiar lesion.Noninvasive treatments are preferabie in early lesions.

The continued decrease in the prevalence of dentalcaries requires much greater caution on the part of

the clinician and a greater focus on accurate diagnosisof caries status and risk factors associated with theformation of new lesions and the progression of exist-ing lesions.' Furthermore, caries not only has de-creased in prevalence, but aiso has changed in patternand progression.- The increased use of fluorides isthought by many to be largely responsible for thischanging pattern of dental caries, an additional benefitbeing conferred on those who have had iifelong expo-sure to water fluoridation.'

The problems in caries diagnosis are usually notassociated with advanced lesions (Fig 1), but primarilyinvolve the eariy iesions (those confined to theenamel).'' It has heen suggested that the diagnosis offissure caries has become more difficult hecause thehigh remineralization capacity of fluorides tends tomask dentinai caries.^-'

"Questionable"' occlusal caries appears to be partic-ularly difficult to diagnose and to treat if the dentist'sgoal is conservative dentistry. For lesions in enamel,treatment consists of improvement in the patient'shome care preventive metbods, application of fluorideor other prophylactic agents, or seahng the fissures.Sometimes it is oniy necessary to practice "watchfuiwaiting."* These procedures are a part of the conserva-tive philosophy (noninvasive treatments), whichcontrasts with the invasive philosophy, which doesnot eliminate the disease and just treats the diseasesymptoms.'

The purpose of this article is to discuss the diag-nosis of occlusal caries and noninvasive treatments forthe management of early caries.

•Graduate Student, Ciinicai Denfal Science, Deparlmerit ot RestorativeOentisfry, School of Dentistry, University of Campinas-UNiCAMR Piraci-caha, Sao Pauio, Brazil.

"Professor, Departmenl of Restorative Dentistry, School cf Dentistry, Uni-versity of Campinas-UN iCAMP, Piracioaba, Sao Pauio, Brazii.

ReprinI requests: Ms Roberta Tarkany Basting, Facuidade de Odcnto-iogia ds Piracicaba-UNiCAMP, Departamento de Odontoiogia Restaura-do ra-Dent 1st ica. Avenida Limeira, 901-Areiào, CEP; 13414-900, Piracicaba,Sào Paulo, Brazil, Fax: 55-19-430-521B,

DIAGNOSIS OF OCCLUSAL CARIES

The diagnosis of occlusal caries presents a consider-able challenge. That is why it is important to diagnosecorrectly, distinguishing lesions that must he treatedrestoratively from those that can be treated in a nonin-vasive way. This procedure is difficult because of the

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Fig 1 Obvious cavitated iesion in an oeciusai surface The diag-nosis of caries is evident, and restorative treatment is neoessary.

Fig 2 Early caries In an ocoiusal surface The white-apot iesionand the brown discoloration in the fissure indioate that demineral-izafion ot the enamei has occurred Bitewing radiography showedno radioiucenoy in dentin.

dynamic nature of dental caries, which includes peri-ods of demineralization and remineralization, mean-ing that the detection of small lesions is particularlyimportant. =

Visual inspection

Early caries in occlusal surfaces usually appears as awhite-spot lesion, with brown discoloration aroundthe fissure, suggesting tbat demineralization of theenamel has occurred (Fig 2). Compared to translucentsound enamel, white spots are opaque because theircrystals have changed physical properties and have adifferent chemical makeup. White spots can be seenaround the opening of an occlusal fissure, and tbeymay have a matte or dull appearance, indicafing activedisease.'" Alternatively, fissures may be stained, andthis appearance may or may not indicate a carious le-sion. Tbe area of enamel around the fissure may alsoappear opaque or may have a grayish tinge indicativeof stained dentinal caries.' Somefimes early stages ofthe lesion are hidden from the naked eye, with largedentinal lesions-beneath seemingly sound occlusalsurfaces'"''^-that may justify restorative treatment.

In arrested lesions, remineraiizing pbases have ex-ceeded demineralizing phases. Fluoride ions and otherminerals have been incorporated in the lesion as partof the consolidation process. A darker discolorationcan be seen in arrested lesions as a result of the extrin-sic organic material incorporated, and these areas aremore resistant to cariogenic challenge.""' This situa-tion can be addressed by noninvasive treatments thatean enhance this process.

Caries can be diagnosed by visual inspection. Aprobe sbould be used only for careful removal of debrisfrom the depths of the fissure.'" Probing may allow

transmission of cariogenic fiora from one infected siteto another. Ftirthermore, it can produce irreversibletraumatic defects in potentially remineralizableenamel, and probing is not more accurate in diagnosisthan visual inspection alone.' ' '•' '^ Because of the pos-sibility of introducing iatrogenic damage, there is rea-son to reconsider tbe probe as a classic invasivemetbod of diagnosis.'̂

Tben, tbe concept of "looking for" caries with theeyes is very important.' To allow reliable detecfion ofthe earliest, clinically visible, manifestation of dentalcaries-tbe wbite spot, teeth should be clean and dry.'Plaque and saliva can obscure these lesions,' and clin-icians working at the cavitation level are more likelyto make false negative diagnoses, missing active cariesthat could be arrested. In addition, the white spot ismore obvious when teeth are dry because of the differ-ent refractive indices of enamel, water, and air." Tberefractive index of enamel is 1.62. Wben demineral-ized, enamel becomes porous. If the teetb are wet,these pores are filled with a watery medium with arefractive index of 1.33; when the porosity is consider-able, this difference in refractive index will cause thetissue to lose its translucence and appear opaque. Ifthe enamel is dried, the water is replaced with air,which has a refractive index of 1.0; the difference inrefractive index between the air and the enamel isgreater than that between water and enamel, so tbelesion is more obvious.

When assessing a carious lesion, tbe dentist sbouldfirst ask, "Is there active caries?" instead of, "Is therecaries?"' Many times, lesions can be arrested if aconcept of treafing these diseases as infections ratherthan just treating the disease symptoms is adopted.*The concept of "lesion behavior" rather than "lesionprogression," now seems more logical because it

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avoids any implication of unavoidable and unremittingactivity."^ Thus, dentists can apply more efficient andrealistic methods for better patient care and treatmentbased on the identification of caries risk or cariesactivity.'̂

Patient history

However, dentists continue, currently, to have diffi-culty in differentiating active from arrested lesions andusually base tbeir decision on "clinical judgment."Failure to diagnose caries may result in the continueddestruction of the dentition.'^ To help in their deci-sions, they should include in the patient's record anassessment of the past caries experience and cariesrisk. They should know the patient's dietary habits,salivary function, plaque localization and consistency,pit and fissure morpbology, and home care preventivemethods (exposure to fluoride, for example).' This sta-tus will identify the rate of caries progression and thenecessity of monitoring caries activity.'̂

Bitewing radiographs

Because no better method for determining the pres-ence and extent of occlusal caries has been developed,it is useful to include information obtained frombitewing radiographs in the diagnosis of occlusalcaries.̂ Radiographs are better than visual inspectionalone," because clinical scoring most frequently un-derestimates lesion depth.-"--' However, the anatomyof posterior teeth is such that large volumes of soundenamei cover the buccal and lingual cusps and, on aradiograph, conspire to mask any incipient demineral-ization in an occlusal fissure." There is a higher fre-quency of false-positive diagnosis in the occiusai areathan in the interproximal area, indicating that the bor-derline between enamel and dentin is difficult to inter-pret radiographically.^' The most dramatic clinicalconsequence is when restorations are placed in soundteeth.

An occlusal radiolucency in the bitewing radio-graph calls for attention, constituting a vaiuable sup-plement to the clinical examination,' and a restorativetechnique is considered necessary when a lesion ex-tends into dentin.̂ -̂̂ ^ However, it is not possible tocorrelate external characteristics, such as where thecaries occurred on the tooth surface, lesion color,presence of shadowing, or the fissure morphology,with the extent of the carious process.^' Radiographsare inaccurate in estimating the extent of the caries orin detecting minimal occlusal lesions but are useful formonitoring the preventive therapy.'^ This vigilance isnecessary to accomplish the ultimate goal of dentistry;to conserve as much tooth structure as possible. '̂'

In conclusion, the modern clinician's aim shouldbe to diagnose caries before cavitation has occurredso that noninvasive treatments may arrest it. To thisend, the clinician should examine clean, dry, andwell-lighted teeth by visual inspection and bitewingradiographs.

NONINVASIVE TREATMENT OF OCCLUSAL CARIES

For teeth with occlusal caries, there is a trertd forselecting the most conservative technique with respectto saving sound tooth substance, preferring nonin-vasive to invasive techniques. Clinicians now have amuch wider range of therapeutic options at their dis-posal for the management of occlusal caries.' Thechoice of treatment is based on the diagnosis,̂ '̂̂ ' andthe accuracy of that diagnosis is of major importance.

A restorative approach is justified when an occlusalcarious lesion has reached the dentin.̂ '•̂ '•̂ '' Because itseems to be a general opinion that dentinal cariesshould be treated operatively, it is important to knowthe amount of dentin involved in an occlusal cariouslesion without visible clinical cavitation.^'

When decisions arc made about restorative care,tbe generally slow average progression rates reportedbave to be weighed against the likely durability of anyrestoration.'" There is evidence that the longevity ofmany restorations may be short. Traditional restora-tive dentistry is the worst alternative for treating incip-ient occlusal caries, suffering from a large number offailures. Recurrent caries can occur at the tooth-restoration interface, indicating that disease is presentThe belief that dental caries can be treated effectivelyby restoring the lesion is an error. A decision to under-take invasive restorative treatment for a tooth may beappropriate only if, at the same time, noninvasive pre-ventive treasures are also applied.'-^'

Sound fissures or those with arrested lesions re-quire no specific treatment. As a matter of fact, ar-rested lesions exhibit a higher degree of resistance todemineralization than do uninvolved areas.'^'^However, where fissure morphology conceals progres-sive, active enamel lesions, preventive techniques arerequired to arrest lesion progression.^^ Noninvasivepreventive care is likely to be centered around coun-seling in oral hygiene, dietary matters, and the homeuse of topical agents such as fluoride toothpaste aswell as possibly the application of fissure sealants.^'

Occlusal surfaces of erupting permanent molars areparticularly susceptible to caries because conditions arefavorable for plaque accumulation. An individualized,nonoperative treatment program can reduce dentalplaque and caries on occlusal surfaces of newly eruptedmolars.^"' The treatment progratn must be based on

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the understanding of dental caries as a local diseaseand intensive training in home-based plaque control.

Special instructions about an appropriate techniquefor plaque control on the occlusal surfaces of partlyerupted permanent molars must be given to thepatient. He or she must be asked for intensive cooper-ation. The toothbrush is held in the buccolingualdirection, with the bristles toward the occlusal surface,and moved with rotary motions.'"

Fluoride toothpastes must be used in conjunctionwith the daily toothbrushing, constituting at-homepreventive care. At the dentist's office, the therapeuticuse of fluorides can be conducted. So. the cliniciancan also reinforce the plaque control of the patient,emphasizing the necessity of consistent use of a fluo-ride toothpaste. The effectiveness of fluoride againstcaries is known, and the frequency of fluoride pres-ence in the oral fluid is a strong factor in cariostasis.Improved methods of delivering low, but effective, lev-els of fluoride, either more frequently or over pro-longed periods, are beneficial for the increased effi-cacy of fluoride against earies.̂ ^

Another technique used by clinicians is "watchfulwaiting'' or réévaluation at the next appointment. Thistechnique may be combined with topical fluoridetreatment and dietary counseling that could providethe opportunity for arrest of the iesion and reminerai-ization and a return to a clinically sound state."

Sealant is usually placed when an active enamelcarious iesion shows signs of progression, when thepatient presents high caries risk and cannot controlthe dental plaque efficiently by toothbrushing, orwhen the patient does not cooperate with the pro-posed treatment. Sealant is considered interceptive,rather than preventive, because the carious process insmall lesions, and occasionally in larger lesions, mayhe arrested after sealing.^'"-'^ If the sealant is main-tained and the nutrients are prevented from enteringin the fissure, there is a continual reduction in the via-hility of the remaining bacteria.^*

There appears to be some evidence of the effectcaused by glass-ionomer cement on the consistencyof remaining carious dentin." However, it would bepremature to conclude that complete removal of cari-ous dentin need not be carried out when glass-ionomer cements are used. Although enamel cariesean be arrested by the use of sealant, means of diag-nosing occlusal caries are no less important,"Therefore, once the carious process has reached thepoint where bacteria have infected the dentin, removalof the infected tissue and its replacement with arestoration may be the treatment of choice.'*

In recent years, chlorhexidine has become availableas vamishes and has already been shown capable ofreducing Streptococcus mutans and demineralization

in several studies.'^ -"̂ Streptococcus mutans was sup-pressed in occlusal fissures for 2 months after oneapplication of 40% chlorhexidine varnish," The majoradvantages of its use seemed to be the lack of dis-coloration of teeth, the longer retention, and theabsence of bad taste for the patient because of thelocal application in occlusal surfaces.

The use of fluoride varnishes in conjunction withan antimicrobial solution, such as 0.2°!i) ehlorhexidinegluconate, may enhance the remineraiization of theaffected enamel in the fissure in vitro.-"-! Therefore, notonly would the infection be controlled by the reduc-tion of Streptococcus mutans, but also the structuralloss caused by the carious lesion would be repaired.

From this range of noninvasive treatments, the pro-fessional can choose the best for the patient, associat-ing compatible methods for specific cases, allied withhealth promotion.'' Once a noninvasive approach toone or more carious lesions in an individual has beenadopted, continued vigilance will be required so thatany progression of the caries can be monitored andmanaged accordingly.̂ Furthermore, clinicians shouldbe conscious of their diagnostic performance, adjust-ing their treatment philosophy to emphasize accuratediagnoses, resulting in fewer unnecessary restorations.Dentists who make the diagnosis and the treatment ofcaries fit the patient's risk will be rendering the bestprofessional service.

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