Approximal Carious Lesions Research Articles

Influence of Number of Surfaces and Observers on Statistical Power in a Multiobserver ROC Radiographic Caries Detection Study

The aim of the study was to evaluate the influence of the number of surfaces (N_surf) and the number of observers (N_obs) on the statistical power of a study comparing the diagnostic accuracies of radiographic systems used for approximal caries lesion detection. A data set consisting of 338 surfaces examined by 10 independent observers using four radiographic systems was available. The presence of a caries lesion was assessed from a 5-point confidence scale. The true lesion diagnosis was established by histological validation. ROC curve areas (A_zs) were used to express the diagnostic accuracy of the observers with the radiographic systems. Assuming that the A_zs were tested by a two-way analysis of variance, we performed a simulation study in order to evaluate how the power of this statistical analysis depended on N_surf and N_obs. As a measure of the statistical power we used the standard error of the difference between the expected A_zs of two systems. The simulations were made with N_surf in the range from 25 to 338 and N_obsfrom 2 to 10. The simulations showed that the power increased as a function of the total number of evaluations per system (N_surf× N_obs), but how this number was attained in relation to the number of surfaces and observers had only marginal influence on the power. Thus, from a statistical point of view it may be concluded, provided that data are analyzed by a two-way analysis of variance, that study designs for comparing the accuracy of several systems can be composed freely in relation to the number of surfaces and observers as long as the total number of evaluations per system are identical.

Relationships between a Clinical-Visual Scoring System and Two Histological Techniques: A Laboratory Study on Occlusal and Approximal Carious Lesions

One aim of the present laboratory study was to determine whether a visual scoring system (ERK) developed for occlusal caries could be applied to approximal lesions. A new histological technique (autofluorescence, AF) recognises dentine that is soft and would be removed with an excavator during operative treatment. A second aim was to investigate the relationship between the visual scoring system (ERK) and AF of dentine both occlusally and approximally. The sample comprised 93 extracted teeth chosen to represent the range of visual scores on approximal and occlusal surfaces. After sectioning through the investigation site, the cut faces were examined in a stereomicroscope and the depth of demineralization was scored. Autofluorescence was viewed with a confocal laser scanning microscope. Results showed reasonable correlation between the visual scores and the stereomicroscope histological evaluations for occlusal surfaces and non-cavitated approximal surfaces. However, cavitated approximal surface lesions were less advanced histologically than cavitated occlusal carious lesions. The AF technique indicated that several lesions with intact surfaces would have had soft, excavatable dentine, whereas several with microcavities would not.

In vitro assessment of incipient approximal carious lesions using computer-assisted densitometric image analysis

Objectives. To investigate the use of computer-assisted densitometric image analysis (CADIA) to detect incipient approximal carious lesions in vitro and to compare areas of demineralization and mechanically induced lesions by radiographic visual inspection. Methods. Thirty-six extracted non-carious human molars were demineralized in a defined approximal area of interest (AOI) using a gel system (pH 4.8) applied over 15 weeks. Standardized digital radiographs were taken before and after creation of caries-like lesions and grayscale values were measured within the AOI. For another group of eight teeth, artificial defects were mechanically induced by a diamond bur and densitometric analysis was performed. Statistical significance was tested using the Wilcoxon test and set at p≤0.05. In addition, radiographs were interpreted by visual examination by six experienced dentists. The sensitivity and specificity for both study groups were determined in comparison to a baseline group of untreated teeth. Polarized light microscopy and SEM analysis were used to evaluate changes in the subsurface mineralization pattern and surface micromorphology. Results. Densitometric comparison of images from identical regions in control teeth revealed no significant grayscale value differences within the AOI, whereas a significant decrease ( p≤0.05) was observed in the demineralized group. Mechanically induced lesions also showed a significant densitometric decrease ( p≤0.05). The sensitivity of visual inspection of radiographs of demineralized areas was 0%. In contrast, the sensitivity for the detection of a mechanical defect of 0.1 mm, which was the same subsurface extension as the histologically determined demineralization, increased to 52%. Specificity was 100% for all groups. Conclusions. CADIA is able to detect very small changes in mineralization of incipient carious approximal lesions in vitro. The findings presented in this investigation may improve the subtraction method used for diagnosis and monitoring of approximal caries, as well as prophylactic measures.

Reliability of different methods for diagnosis of approximal carious lesions

The aim of this study was to evaluate the diagnosis accuracy of approximal carries by visual, fiber optic transillumination(FOTI) and bitewing radiograph examination performed by two observers.A total of(372) unrestored posterior pertinent approximal surfaces of(186) patients were examined in Conservative Department during final clinical examination for under-graduate students, using the diagnostic methods under the study. The results were compared with the validation.The accuracy of each diagnostic method for identification of cavitated carious lesions was expressed by the terms: sensitivity, specificity and predictive values.The sensitivities for identification of cavitated lesions using visual examination about(0.28), for FOTI and radiography were(0.04) and(0.59) respectively. The specificity collectively was about(0.9).On the basis of these results, it was concluded that FOTI was the least reliable of the diagnostic methods tested. Also, it was found that visual examination should precede theradiographical examination for identification of cavitated carious lesions.

Accuracy of computer‐automated caries detection in digital radiographs compared with human observers

The aim of this study was to compare diagnostic accuracy of a caries detection program with that of human observers. A total of 190 extracted teeth were radiographed with two Trophy RVG (RadioVisioGraphy) digital sensor systems. Four observers scored the approximal surfaces in all images on a disease severity scale. Each observer thereafter used the Logicon Caries Detector (LCD) program to analyse the surfaces in the digital images and recorded their outcome. To determine the true absence or presence of caries, histological validation was used. Sensitivities, specificities, positive and negative predictive values were calculated and differences between the diagnostic methods tested. Specificities for the outcome with the LCD were significantly lower for three observers than when they themselves assessed the RVG images and, correspondingly, the positive predictive values were lower for the LCD outcome for three of the observers. Sensitivity was also lower for two observers on the diagnostic threshold caries in dentine. It was concluded that the automated caries detection program is less accurate than human observers in detecting approximal caries lesions.

A study to assess the use of fibre-optic transillumination in the general dental practice

Objective To assess the use of fibre-optic transillumination (FOTI) as a diagnostic tool in general dental practice. Design A cross-over quantitative study for the diagnosis of approximal carious lesions by two clinical methods with a qualitative component. Subjects and methods Seven GDPs were trained to use FOTI as an adjunct to their usual clinical examination to diagnose approximal caries. After 12 weeks of use in their practices four of the GDPs took part in two assessment sessions, set a week apart, using 29 volunteer patients. Each patient was examined on two separate occasions by each GDP using either their standard clinical examination technique alone or supplemented by FOTI examination. The order of the techniques was randomised. Radiographs of each patient were also examined separately. An experienced FOTI user also examined the patients to provide a benchmark. From standard charts the number of enamel and dentinal lesions on approximal surfaces was summed and comparisons made between the techniques. Six GDPs took part in one-to-one interviews. Main outcome measures Mean numbers of carious lesions recorded by each clinician using each technique. Results There was a trend for all GDPs to find more enamel and dentinal lesions using FOTI, than with their standard clinical examination with or without radiographs. All GDPs found the FOTI technique a useful adjunct. They used FOTI in different ways and found a variety of uses for it other than caries diagnosis. Conclusions The FOTI technique increased the detection of approximal carious lesions. It was reported to be a useful diagnostic tool in general dental practice. GDPs and staff enjoyed participating in a research project.

Conventional, Digital and Contrast–Enhanced Bitewing Radiographs in the Decision to Restore Approximal Carious Lesions

The purpose of the present investigation was to compare the accuracy of treatment decisions in proximal sites using three intra–oral radiographic systems. Additionally, the impact of an automated non–linear grey–level display was evaluated. Ten observers assessed 84 surfaces on bitewing radiographs for their requirement of restorative treatment using a 6–rank confidence scale. Radiographs were taken with conventional film images (Ultraspeed), a storage phosphor plate (Digora) and a CCD system (Dexis). Additionally, the Dexis software was expanded by a contrast enhancement routine (Dexis+). The restorative treatment threshold was defined as presence of macroscopic cavitation. Regarding the areas below mean ROC curves no significant differences were detected between the groups (p>0.05). Likelihood ratios for positive test results were: 5.29 (Ultraspeed), 8.14 (Digora), 9.67 (Dexis) and 11.37 (Dexis+). The accuracy of restorative treatment decisions based on digital and conventional radiographs is comparable. If a dichotomous treatment decision was requested, the digital systems demonstrated a notable tendency towards higher likelihood of true–positive decisions.

A Clinical and Microbiological Study of Approximal Carious Lesions

A clinical study was carried out to assess relationship between the presence of approximal cavitation, the radiographic depth of the lesion, the site–specific gingival index and the level of infection of the dentine. Adult patients assessed as needing operative treatment and presenting with approximal lesions visible in the outer third of dentine on bite–wing radiographs were included in the study. Direct lesion depth measurements were recorded from the radiographs and the site–specific gingival index adjacent to the lesion was noted. The presence or absence of a cavity was recorded on an impression following tooth separation. During operative treatment samples of dentine were taken on entry to the lesions to ascertain the level of infection of the dentine. Visual evaluation of 54 successfully recorded impressions revealed that 85% were cavitated. Cavitated lesions were found to have higher site–specific gingival index scores compared to non–cavitated lesions (p = 0.03). The probability of cavitation was greater for lesions >0.5 mm from the enamel–dentine junction on bite–wing radiographs (p<0.01). The level of infection of the dentine was significantly higher for cavitated lesions than for non–cavitated lesions (p = 0.02). However, the non–cavitated lesions were still infected.

A Clinical and Microbiological Study of Approximal Carious Lesions

A randomized controlled clinical study was set up to assess caries removal following tunnel preparation (test group) and class II cavity preparation (control group). Sixty approximal lesions in adult posterior teeth, visible in the outer third of dentine on bite–wing radiographs, were referred for operative treatment. Initial dentine samples were taken on entry to the lesions in both groups. Following cavity preparation dentine samples were taken from beneath the marginal ridge in the tunnel group and at the cervical floor in both groups. Microbiological analysis was carried out to establish the level of infection of the dentine. The bacterial counts were high on entry to the lesions with a median log₁₀ (CFU + 1) per sample of 3.07 (±1.24). Following cavity preparation bacterial counts at the cervical floor were significantly reduced in both amalgam and tunnel groups (p<0.00001). In the tunnel group, however, slightly increased bacterial counts were found beneath the marginal ridge compared to the cervical floor (p<0.01).

Distribution and volumetric assessment of initial approximal caries lesions in human premolars and permanent molars using computer-aided three-dimensional reconstruction

Serial sections from 21 extracted premolars and permanent molars, divided into three age groups (group 1, 10–19 years; group 2, 20–39 years; group 3, 50–69 years.), were viewed by polarized light microscopy for reconstruction of the caries lesions. The volumes of the lesional body and the transparent zone, and the volumes of early dentinal lesions were calculated; and an enamel demineralization index (EDI) and an enamel–dentine demineralization index (EDDI), representing the volumetric ratio of the body of the lesion to the translucent zone, and the body of the lesion to the volume of the early dentinal lesion, respectively, were determined. The method showed that there are three typical sites of individual initial caries lesions at the approximal surface: within the contact area, in the subcontact area, and in the cervical area. Volumetric assessment demonstrated a larger volume of the body of the lesion in older teeth with a smaller volume of the translucent zone relative to the lesional body. From these results it can be concluded that there are usually more than one individual initial caries lesions at the approximal tooth surface. Calculation of demineralization indices demonstrated different features for small lesions with pronounced transparent zones and for large lesions with small transparent zones. The computer-assisted three-dimensional reconstruction technique and the volumetric assessment are of value in investigations of the micromorphology and progression of natural caries lesions in permanent teeth.

Swedish dentists' decisions on preparation techniques and restorative materials

This study aimed at mapping the preparation techniques and restorative materials that Swedish dentists are using for primary approximal and occlusal carious lesions. It involved sending a pre-coded questionnaire to a random sample of 923 dentists, with eight items concerning approximal and occlusal restorative preparation techniques and dental materials. Responses were received from 651 (70.5%) dentists. To restore a primary approximal carious lesion in an adolescent with low caries activity and good oral hygiene, the tunnel preparation was chosen by 48% of the dentists, the saucer-shaped preparation by 32%, and the traditional Class II preparation by 20%. The most common preparation technique for restoring an occlusal carious lesion was removal of the carious part only, which was chosen by 74% of the dentists. For a lower second molar with a minor occlusal caries lesion combined with a suspected dentin lesion as judged radiographically, about half of the dentists chose to restore the carious part only and 27% would seal the rest of the fissure system in addition. For a similar lesion with no obvious radiolucency in the dentin, about 1/3 chose the 'no treatment' alternative, 1/3 fluoride treatment, and the rest fissure sealing or other techniques. Composite was used most often and amalgam least often for both approximal and occlusal carious lesions.

Progression rate of approximal carious lesions in Swedish teenagers and the correlation between caries experience and radiographic behavior. An analysis of the survival rate of approximal caries lesions

The objectives were to study the progression rate of approximal caries in 14 to 19-year-old adolescents and to assess the influence of experience of previous caries as a predictor of caries progression during the following years. The study population comprised 100 adolescents, all 19 years old, randomly selected. In all, there were 93 adolescents included in the study, for whom all sets of bitewing radiographs from 14 up to and including the age of 19 were assessed with respect to approximal caries. It could be noted that 32% of the adolescents had had at least one bitewing examination every year from 14 to 19 years of age. At the age of 14, 38% of the males and 24% of the females were radiographically without any sign of caries lesions (caries-free). The median survival time of initial caries in the present study was >5 years, while for manifest caries it was 3.2 years. It was found that 37% of the surfaces with manifest caries in males and 18% of the corresponding surfaces in females were restored within a year. The results show that experience of previous caries does not seem to be a significant indicator and does not influence when the next radiographic examination should be performed. It is thus concluded that individualized bitewing examination is the exception rather than the rule.

Behaviour of Approximal Carious Lesions Assessed by Clinical Examination after Tooth Separation and Radiography: A 2.5–Year Longitudinal Study in Young Adults

This study aimed to record and monitor over a 2.5–year period the occurrence of cavitation and lesion depth progression in approximal surfaces with radiographic caries at baseline. In total, 66 approximal sites (in 29 students), where at least one of the contacting surfaces had radiographic caries, were selected to take part in the study. A clinical examination undertaken before and after tooth separation in order to assess the presence/absence of cavitation was repeated every sixth month. To monitor lesion progression bite–wing radiographs were taken every sixth month, too. After each series of examinations, surfaces judged to be prone for disease progression were referred to operative caries treatment. In surfaces with radiographic dentinal caries at baseline the cavitation prevalence following tooth separation found at the various recall examinations ranged from 20 to 44%. In surfaces with radiographic enamel caries at baseline this prevalence ranged from 4 to 8% at the various recall examinations. In dentinal lesions found with an intact surface at baseline, the risk of cavitation development during the first 1.5–year period was assessed to be up to 22%. After this period no new cavitations were found in previously intact dentinal lesions. In intact enamel lesions the risk of cavitation formation was found to be 3% during the first 1–year period. After this period no new cavitations developed in previously intact enamel lesions. Three of 7 lesions, which showed radiographic caries progression from the outer one third to the inner two thirds of the dentine during the observation period, had intact surfaces at baseline. On the basis of these results it is recommended to re–examine carefully intact, dentinal lesions by repeated clinical examination after tooth separation and by radiography about 1–1.5 years after baseline.

Caries assessment and restorative treatment thresholds reported by Swedish dentists

The aim was to study any variability in approximal and occlusal caries diagnoses and restorative treatment decisions among Swedish dentists. The material consisted of a pre-coded questionnaire sent to a random sample of 923 dentists with 4 items concerning approximal and occlusal caries diagnosis and restorative treatment decisions. Responses were received from 651 (70.5%) dentists. In an adolescent with low caries activity and good oral hygiene, more than 90% of the dentists stated that they would not automatically restore a primary approximal caries lesion if its radiographic appearance did not show obvious progression in the outer 1/3 to 1/2 of the dentin. Moreover, 67% of the dentists would only consider immediate restorative treatment of an occlusal surface if obvious cavitation and/or radiographic signs of dentin caries could be observed. When diagnosing questionable occlusal caries, the dentists largely relied on the radiographic appearance. Concerning both approximal and occlusal caries, the threshold for restorative treatment differed between the metropolitan regions in Sweden, and younger more often than older dentists would postpone restorative treatment of approximal caries until the lesion had reached a relatively advanced stage of progression. The responses also showed that dentists in private practice would restore approximal caries at an earlier stage of progression than the dentists in the Public Dental Health Service.

Influence of the addition of restorations on the diagnosis of caries from digitized bitewing radiographs

Objectives. The purpose of this study was to assess the influence of additional caries and restorations on the detection of caries on the same radiograph. Study design. Six participants examined five series of four radiographs in which natural carious lesions were present. Each series consisted of the same image with progressively more restorative treatment digitally painted on. The films were randomly presented to the observers who examined the films for the presence and depth of carious lesions. The observers were not informed that the 20 films were disguised versions of the same original five radiographs. Results. The number of carious lesions reported by the six observers did not increase despite the apparent increased restorative intervention viewed on the radiographs. Conclusions. The complexity of restorative care does not affect observers' ability to correctly detect approximal carious lesions.

Quantitative diagnosis of small approximal caries lesions utilizing wavelength-dependent fiber-optic transillumination.

The instruments clinically available for the diagnosis of approximal caries lesions are inadequate to detect lesions early and quantitatively. The aim of this study was to investigate whether wavelength-dependent light scattering and absorption of carious tissues may be utilized for the quantitative diagnosis of these small approximal caries lesions. Seventeen extracted premolar teeth were transilluminated at an approximal surface with a glass fiber, which transported the light from a halogen light bulb. Seven approximal surfaces contained a naturally developed small white-spot lesion, and 5 surfaces a small discolored lesion. Five teeth were sound. The occlusal surface was imaged with a CCD camera. Light in the blue and red portions of the electromagnetic spectrum was selected by means of Schott glass filters. From the obtained images, average effective decadic optical thickness differences were determined. These were plotted as a function of average mineral loss assessed by means of wavelength-independent microradiography. The correlation coefficient between the average effective decadic optical thickness difference and average mineral loss was r = 0.79 (95% CI: 0.47 ... 0.93). Different sources of variation that influence the observed correlation were defined and quantified. From these measurements, the correlation coefficient between average effective decadic optical thickness difference and "true' average mineral loss was estimated to be r = 0.92 (95% CI: 0.77 ... 0.97). The results indicate that early and, in principle, also quantitative diagnosis of approximal caries lesions is feasible when wavelength-dependent light propagation through carious tissues is utilized.

Interpretation of bitewing radiographs. Part 2 evaluation of the size of approximal lesions and need for treatment

Objective: The decision to treat initial approximal carious lesions is based mainly on interpretation of bitewing radiographs. In a previous report, it was shown that artificial approximal lesions of uniform size are more readily detected on radiographs in premolars than in molars. The objective of the present study was to compare the ability to evaluate the depth of similar size artificial lesions on radiographs and reach decisions concerning treatment, in premolars and molars. Method: Clinicians were asked to evaluate on radiographs, the size of in vitro prepared artificial lesions, and decide at which point they would perform a restoration. Results: Significant differences were found in the evaluation of lesion depth between different tooth surfaces. The interaction between lesion depth and tooth surface originated from the examiners' trend to score same size lesions as penetrating deeper into the tooth in premolars than in molars. The probability of the examiners to decide on restorative treatment in shallow lesions (0.25 mm, 0.50 mm) was higher in premolars than in molars. Conclusions: The findings suggest that clinicians evaluate initial lesions as being deeper and more prone to treatment in premolars than in molars.

Restoration of approximal carious lesions--application of decision analysis.

Abstract This study uses decision analysis in order to explore the maximum expected utility of positive and negative restorative decisions, made on the basis of bitewing radiography. The a posteriori probabilities of disease, given a positive/negative treatment decision were derived from a study in which 20 dentists made 7200 decisions about 15 pairs of simulated bitewing radiographs. Lesion depths in the teeth examined were ascertained by light microscopy. A review of the available data on lesion progression/regression was undertaken to provide probability values for the decision model, and population utilities for the outcomes of the decision were derived from a survey of 110 members of the public. The decision analysis showed that negative treatment decisions always attracted the highest maximum expected utility, except in highly disease‐prone individuals. This analysis demonstrates that lesion depth, likelihood of pain, and the rate of lesion progression have minimal effect on the utility of a positive treatment decision. It is concluded that an over‐concentration on the biomedical model of dental health may cause dentists to make decisions which are inappropriate to their patients' values and preferences.

Light propagation through teeth containing simulated caries lesions

The methods currently utilized in dentistry to detect caries lesions have their limitations and alternatives are being investigated. A promising option is tooth transillumination which is based on an increase of light scattering or light absorption in the affected tissue region. In this study transillumination applied to detect approximal caries lesions was investigated using premolar teeth containing simulated caries lesions. Cavities were drilled at the approximal surface and filled with light absorbing and light scattering fluids in different dye and particle concentrations to model successive stages of lesion progress. For light absorbing cavities the extinction as function of the decadic absorption coefficient measured at the occlusal surface could be approximated by the Lambert-Beer law (r=0.98+or-0.01). For light scattering cavities the extinction as a function of the decadic reduced scatter coefficient was fitted to a straight line (r=0.98+or-0.03) for mu 's( lambda =633 nm)<1.25 mm-1. For higher reduced decadic scatter coefficients the curves levelled off due to multiple scattering. In addition, the contribution of the dentinal cavity part to the radiance change induced by the total cavity was estimated. For light absorbing cavities illuminated with red light the average contribution was 10.5 (SD 4.2)% and for those illuminated with green light it was 1.4 (SD 0.9)%, indicating that the radiance change caused by a caries lesion is mainly determined by the enamel lesion part.

Effect of a 3-Year Professional Flossing Program with Chlorhexidine Gel on Approximal Caries and Cost of Treatment in Preschool Children

The aim was to evaluate the effect of chlorhexidine gel treatment on the incidence of approximal caries in preschool children. One hundred and seventeen 4-year-olds, divided into two groups, participated: (1) chlorhexidine gel group (n = 59), and (2) placebo gel group (n = 58). Group 1 was treated 4 times a year with a 1% chlorhexdine gel and group 2 with a placebo gel. Approximately 0.7 ml of gel was applied interdentally by means of a flat dental floss. A control group (group 3), which did not receive any flossing or gel treatment, was also included in the study (n = 116). After 3 years, i.e. when the children were 7 years old, the mean incidence of caries on approximal surfaces (defs), including both enamel and dentin lesions, was 2.59 in the chlorhexidine gel, 4.53 in the placebo gel and 4.20 in the control group (group 1 vs. 2 and group 1 vs. 3: p < 0.01). Mean number of approximal fillings at the end of the study, i.e. when the children were 7 years old, was 0.33 in the chlorhexidine gel, 1.04 in the placebo gel and 0.80 in the control group (group 1 vs. 2: p < 0.01; group 1 vs. 3: p < 0.05). The progression of approximal caries lesions, diagnosed on bitewing radiographs from the age of 5 to 7, was slower in the chlorhexidine than in the placebo gel group (the control group was not evaluated in this respect). A cost analysis, based on the total treatment time in minutes, showed a small gain for the flossing program.(ABSTRACT TRUNCATED AT 250 WORDS)