4 IntroductionDental caries is a multifactorial disease with interactionsamong three factors: the tooth, the microflora, and thedietCaries is an infectious disease since it is the lactic acidproduced by bacteria from the fermentation of the CHthat causes the demineralization of the dental hard tissuesThe initial carious lesion is a subsurface loss of mineralin the outer tooth surface. It appears clinically as a chalkywhite or an opaque or dark, brownish spot
5 Use of Intraoral Radiographs Radiography is useful for detecting dental caries becausethe caries process causes demineralization of enamel anddentin.The lesion is seen in the radiographs as a radiolucent (dark)zone since the demineralized area of the tooth do not absorbas many x-ray photons as the unaffected portion.The radiograph can not detect if the lesion is active or arrested(unless you have different radiographs at different times andyou can see the progression of the lesion)
6 Use of Intraoral Radiographs Radiography is a valuable supplement to a thorough clinicalexamination of the teeth for detecting cariesHowever, even the most meticulous clinical examination mayfail to reveal demineralization beneath the surface, includingocclusal surfacesClinical access to proximal tooth surfaces in contact is limitedSeveral clinical studies have shown that a radiographicexamination can reveal carious lesions both in occlusalAnd proximal surfaces that would otherwise remain undetected
7 Radiographic examination to detect caries The BW projection is the most useful radiographic examination fordetecting cariesThe use of a film holder with a beam-aiming device reduces thenumber of overlapping contact points and improves image qualityPeriapical radiographs are useful primarily for detecting changes in theperiapical bone (use of paralleling technique increases the value ofthis projection in detecting caries)Traditionally size 2 “adult” films are used for a BW examination from theage of 7-8 years onward
8 Radiographic examination to detect caries In recent decades there has been a dramatic decline in the prevalenceof caries in all western countries. Accordingly, the interval betweenexamination should be customized for each individual patient andbased on the perceived caries activity and susceptibility.Radiographs used to detect carious lesions should be mounted inframes with dark borders and interpreted using a magnifying glass.
9 Radiographic detection of lesions Proximal surfaces The shape of the early radiolucent lesion in the enamel is classicallya TRIANGLE with its broad base at the tooth surface, spreadingalong the enamel rods, but OTHER appearances are common suchas a “band” or a “thin line”When the demineralization front reaches the dentino-enamel junction(DEJ), it spreads along the junction, frequently forming the base ofa second TRIANGLE with apex directed towards the pulp chamber.A lesion of proximal surfaces MOST COMMONLY is found in the areabetween the contact point and the free gingival margin. The fact thatthe lesion does not start below the gingival margin helps distinguisha carious lesion from cervical burnout
11 Radiographic detection of lesions Classification of the interproximal cariesIncipient Extends less than halfway through the thickness of theenamel (it is only in enamel !!)Moderate Extends greater than halfway through the thickness of theenamel, but does not involve the DEJAdvanced Extends to the DEJ and into the dentin, but does notextends through the dentin greater than half the distancetowards the pulpSevere Extends through the enamel, dentin and greater thanhalf the distance towards the pulp
12 From Radiographic caries interpretation, Dr. Haring, OSU
21 Radiographic detection of lesions Proximal surfaces Cervical Burnout Diffuse radiolucent areas with ill defined borders may be apparentradiographically on the mesial or distal aspects of the teeth in the cervicalregions between the edge of the enamel cap and the crest of the alveolarridge cervical burnoutThis is caused by the normal configuration of the teeth whichresults in decreased x-ray absorption in the mesial and distalaspects of the teeth
23 Radiographic detection of lesions Proximal surfaces Close attention should be paid to intact proximal surfaces adjacent toa tooth surface with a restoration since occasionally this surface isinadvertently damaged during the restorative procedure and is thusat greater risk for cariesThe proximal surfaces of posterior teeth are often broad, the loss ofsmall amounts of mineral form incipient lesions and the advancing frontof active lesions are often difficult to detect in the radiograph.Lesions confined to enamel may not be evident radiographically untilapproximately 30% to 40% demineralization has occurred
24 Radiographic detection of lesions Proximal surfaces Even experienced dentist often do not agree on the presence orabsence of caries examining the same set of radiographs, especiallywhen the lesions are limited to enamel.A lesions extending into the dentin in the radiograph may be easierto detect with greater agreement among experienced observersPotentially, a progressing proximal lesions may be arrested if cavitationhas not developed. If cavitation has occurred, the lesions will always beactive since the bacteria that colonize within the cavity cannot beremoved.
25 Radiographic detection of lesions Proximal surfaces Experience !!CariesDetectionYears5 years ofpractice
26 Radiographic detection of lesions Occlusal Surfaces Carious lesions in children and adolescents most often occur onocclusal surfaces of posterior teeth.The demineralization process originates in enamel pits and fissures,where bacteria plaque can gather.The lesion spreads along the enamel rods and, if undisturbed, penetratesto the DEJ, where it may be seen as a thin radiolucent line betweenthe enamel and the dentin.Occlusal lesions commonly start in the sides of a fissure wall rather thanat the base and then tend to penetrate nearly perpendicular towards theDEJ
27 Radiographic detection of lesions Occlusal Surfaces When an occlusal lesion is confined to enamel, the surrounding enameloften obscures the lesion. As the carious process progresses, aradiolucent line extends along the DEJ. As the lesions extend into thedentin, the margin between the carious lesion and non carious dentin isdiffuse.The classic radiographic appearance of occlusal caries extending intothe dentin is a broad-based, radiolucent zone, often beneath a fissure,with little or no apparent changes in the enamel
31 Radiographic detection of lesions Buccal and Lingual surfaces Buccal and lingual carious lesions often occur in enamel pits andfissures of the teeth. When small, these lesions are usually round; asthey enlarge, they become elliptical or semi-lunar.It is difficult to differentiate between buccal and lingual caries on aradiograph. When viewing buccal or lingual lesions, the clinicianshould look for a uniform non-carious region of enamel surroundingthe apparent radiolucency.Clinical evaluation is the definitive method
33 Radiographic detection of lesions Root surfaces Root surface lesions involve both cementum and dentin and areassociated with gingival recession. The exposed cementum is relativelysoft and usually only 20 to 50 µm thick near the CEJ, so it rapidlydegrades by attrition, abrasion, and erosion.Root surface caries should be detected clinically, and often radiographsare not necessary.In proximal root surfaces radiographic examination may reveal lesionsthat have gone undetected.Difficult to differentiate between cervical burnout and caries
35 Radiographic detection of lesions Associated with dental restorations A carious lesion developing at the margin of an existing restorationmay be termed secondary or recurrent caries. It should be noted, though, that a lesion developing in a restored surface is mot frequently a newprimary demineralization.These lesions should be treated like any new caries lesion.It is important not to confuse secondary caries with residual caries, whichis caries that remain if the original lesion is not completely removed.A lesion next to a restoration may be obscure by the radiopaque imageof the restoration detection careful examination !!!
36 Radiographic detection of lesions Associated with dental restorations Restorative materials vary in their radiographic appearance dependingon thickness, density, atomic number, and the x-ray beam energy usedto make the radiograph some materials can be confused with caries:calcium hydroxide is a good example
39 Radiographic detection of lesions Interpretation TIPS !! (You will need it)All films must be properly mountedMounted films should be viewed in a room with subdue lighting that isfree of distractionsAn illuminator or viewbox is MANDATORYIf the screen of the viewbox is not completely covered by the mountedradiographs, the harsh light around mounted films must be masked toreduce glare and intensify the detail and contrast of the radiographimagesMagnifier mandatoryUse multiples views of the same area
40 Radiographic detection of lesions Factors influencing caries interpretationErrors in technique may result in non-diagnostic films. For example,a BW that is used to detected dental caries must be free of overlappedcontacts. Improper horizontal angulation causes overlapped contactareas and makes impossible to interpreted the interproximal regions
42 Radiographic detection of lesions Conditions resembling caries Restorative materialsComposites, silicates and acrylics, may resemble cariesCareful examination helps to identify the well definedsmooth outlines of the preparation
44 Radiographic detection of lesions Conditions resembling caries AbrasionAbrasion refers to the wearing away of tooth structure from the friction withan foreign object for example tooth brushingOn radiographs, tooth abrasion appears as a well defined horizontal radiolucencyalong the cervical region of a tooth
45 Radiographic detection of lesions Conditions resembling caries Again….Cervical Burnout (IMPORTANT)Cervical burnout appears as a collar or wedge-shaped radiolucency on the mesial and distalroot surfaces NEAR the CEJ of a toothMay be confused with root caries look at theAlveolar bone level