Lesions In Primary Molars Research Articles

Ex vivo Evaluation of Caries Infiltration after Different Application Times in Primary Molars

Low viscosity resins (infiltrants) have been shown to penetrate the lesion body of natural caries lesions almost completely in vitro. However, penetration depths (PD) have not been evaluated in vivo. Therefore, the aim of the present study was to evaluate the penetration of an infiltrant into proximal caries lesions in primary molars after different application times using an ex vivo model. 59 proximal lesions from 34 children were randomly allocated to one of the application times and were infiltrated under clinical conditions for 1, 3, or 5 min. After extraction or exfoliation (n = 48), teeth were sectioned perpendicular to their surfaces and lesion depths (LD) as well as lesion areas (LA) were evaluated using polarized light microscopy. PD and penetration areas (PA) were measured on scanning electron microscopic images. Percentage penetration depth (PPD) and percentage penetration area (PPA) were calculated. The mean (±SD) LD and LA were 596 ± 203 µm and 4.03 ± 2.75 × 10⁵ µm², respectively. PPD ranged from 70 to 80% and PPA from 54 to 60%. Longer application times did not result in significantly deeper or more complete penetration (p > 0.05; ANOVA). In conclusion, proximal caries lesions in primary molars can be infiltrated in vivo to a similar extent as observed previously in vitro. Moreover, 1-min application of the infiltrant led to PD and homogeneity similar to those observed with longer application times up to 5 min.

An experimental study on the penetration abilities of resin infiltration into proximal caries lesions in primary molars

To compare the penetration abilities of resin infiltration into proximal lesions in primary molars with those of adhesive in vitro. Thirty-two extracted or exfoliated primary molars showing proximal white spot lesions were selected. Roots of the teeth were removed, and the crowns were cut across the white spot lesions perpendicular to the surface. Cut surfaces were examined (by stereo microscopy) and classified with respect to histological lesion extension (C1-C4): lesions confined to the outer half on enamel (C1), lesions confined to the inner half on enamel (C2), lesions confined to the outer half on dentin (C3), lesions extending into the inner half of dentin (C4). Corresponding lesion halves were etched for 120 s with 15% hydrochloric acid gel and were subsequently treated with either adhesive or resin infiltration. Specimens were observed with laser scanning confocal microscope (LSCM) in dual fluorescence mode. In confocal microscopic images, lesion depth and penetration depth of the resin infiltration or the adhesive in corresponding halves were measured, and penetration percentages were calculated respectively. Differences of the data between two groups were analyzed by Wilcoxon signed rank test. Variations of histological caries extensions were detected with Kruskal-Wallis H test. At the same grading level (C1-C3) in histological caries extension, penetration depths of the resin infiltration group and the adhesive group were 240 (230, 260) µm vs 190 (150, 210) µm, 405 (300, 523) µm vs 180 (160, 200) µm, and 590 (430, 640) µm vs 180 (160, 200) µm respectively. There was significant statistical difference in the data between two groups (P < 0.05). Statistically significant difference in penetration depths of the resin infiltration group (at C1-C3) were found (P < 0.01). At the same grading level (C1-C3) in histological caries extension, percentage penetrations of the resin infiltration group and the adhesive group were [100.0% (96.2%, 100.0%)], [99.1% (95.7%, 100.0%)], [82.0% (81.1%, 92.2%)] and [79.2% (68.4%, 87.5%)], [41.8% (29.1%, 74.5%)], [30.2% (29.2%, 39.6%)], respectively. The difference between the above data was also significant (P < 0.05). Percentage penetrations of the resin infiltration group at C1 and C2 level was higher than those at C3 level (P < 0.05). The resin infiltration is capable of penetrating almost completely into proximal lesions in primary molars.

Radiographic and Laser Fluorescence Methods Have No Benefits for Detecting Caries in Primary Teeth

Clinical guidelines advise that dentists take radiographs in children to detect caries lesions missed by visual inspection; however, due to the current low caries prevalence in most countries, we hypothesized that the adjunct methods of caries detection would not significantly improve the detection of primary molar lesions in comparison to visual inspection alone. We evaluated the performance of visual inspection, alone or in combination with radiographic and laser fluorescence pen (LFpen) methods, in detecting occlusal and approximal caries lesions in primary molars. Two examiners evaluated children who had sought dental treatment with these diagnostic strategies. The reference standard involved the temporary separation of approximal and operative interventions for occlusal surfaces. The sensitivity, specificity, accuracy and utility of diagnostic strategies were calculated. Simultaneous combined strategies increased sensitivities but decreased specificities. Furthermore, no differences were observed in accuracy and utility, parameters more influenced by caries prevalence. In conclusion, adjunct radiographic and laser fluorescence methods offer no benefits to the detection of caries in primary teeth in comparison to visual inspection alone; hence, present clinical guidelines should be re-evaluated.

An in vitro Comparison of Detection Methods for Approximal Carious Lesions in Primary Molars

Background/Aims: This study aimed to compare and contrast in vitro six methods to determine the most accurate method for detecting approximal carious lesions in primary molars. Methods: Extracted primary molars (n = 140) were stored in 0.02% chlorhexidine solution and mounted in light-cured resin in pairs. The six carious lesion detection methods used by the three examiners to assess approximal carious lesions were visual inspection, digital radiography, two transillumination lights (SDI and NSK), and two laser fluorescence instruments (CDD and DDP). Five damaged teeth were discarded. The teeth (n = 135) were sectioned, serially ground, and examined under light microscopy using Downer’s histological (HST) criteria as the gold standard. Intra- and inter-examiner reliability, agreement with HST, specificity, sensitivity, receiver operating characteristic (ROC) curves, and areas under the curve were calculated. Results: This study found visual inspection to be the most accurate method when validated by histology. Transillumination with NSK light had the highest specificity, and digital radiography had the highest sensitivity for detecting enamel and/or dentinal carious lesions. Combining specificity and sensitivity into the area under ROC curves, enamel plus dentinal lesions were detected most accurately by visual inspection followed by digital radiography; dentinal lesions were detected most accurately by digital radiography followed by visual inspection. Conclusions: None of the four newly developed methods can be recommended as suitable replacements for visual inspection and digital radiography in detecting carious lesions on approximal surfaces of primary molars, and further developmental work is needed.

Penetration of Experimental Infiltrants with Different Penetration Coefficients and Ethanol Addition into Natural Caries Lesions in Primary Molars

This study evaluated the influence of the penetration coefficient (PC) and ethanol addition on the penetration depth (PD) of experimental infiltrants into proximal caries lesions in primary molars. Caries lesions (n = 45) were randomly treated with 1 of 4 experimental infiltrants (PC63; PC185; PC204; PC391) for 5 min. Lesion depths and PDs were analysed using dual fluorescence confocal microscopy. Lesions were almost completely infiltrated in all groups. Median PDs and percentage penetrations were not significantly different between groups (p > 0.05). When applied for 5 min, all tested infiltrants were able to infiltrate proximal caries in primary molars nearly completely.

Performance of fluorescence‐based and conventional methods of occlusal caries detection in primary molars – an in vitro study

This in vitro study aimed to test the performance of fluorescence-based methods in detecting occlusal caries lesions in primary molars compared to conventional methods. Two examiners assessed 113 sites on 77 occlusal surfaces of primary molars using three fluorescence devices: DIAGNOdent (LF), DIAGNOdent pen (LFpen), and fluorescence camera (VistaProof-FC). Visual inspection (ICDAS) and radiographic methods were also evaluated. One examiner repeated the evaluations after one month. As reference standard method, the lesion depth was determined after sectioning and evaluation in stereomicroscope. The area under the ROC curve (Az), sensitivity, specificity, and accuracy of the methods were calculated at enamel (D1) and dentine caries (D3) lesions thresholds. The intra and interexaminer reproducibility were calculated using the intraclass correlation coefficient (ICC) and kappa statistics. At D1, visual inspection presented higher sensitivities (0.97-0.99) but lower specificities (0.18-0.25). At D3, all the methods demonstrated similar performance (Az values around 0.90). Visual and radiographic methods showed a slightly higher specificity (values higher than 0.96) than the fluorescence based ones (values around 0.88). In general, all methods presented high reproducibility (ICC higher than 0.79). Although fluorescence-based and conventional methods present similar performance in detecting occlusal caries lesions in primary teeth, visual inspection alone seems to be sufficient to be used in clinical practice.

Penetration depths of an infiltrant into proximal caries lesions in primary molars after different application times in vitro

Caries infiltration aims to inhibit lesion progression, by occluding the porosities within the lesion body with low-viscosity resins. The ability in hampering lesion progression is correlated with the penetration depth (PD) of the infiltrant. This study aimed to compare the infiltration depths into proximal lesions in primary molars after different application times. Noncavitated natural caries lesions (n = 83) were etched with 15% HCl for 2 min and infiltrated for 0.5, 1, 3, or 5 min. Specimens were sectioned and PD at the maximum lesion depth (LD(max)) were analysed using dual fluorescence confocal microscopy. Percentage penetrations (PD/LD(max)) were significantly higher after 3 or 5 min compared with 0.5-min application (P < 0.05; Mann-Whitney test). For LD(max) <400 μm, no significant differences were observed between application times (P > 0.05). For LD(max) ≥400 μm, 3- and 5-min application resulted in significantly deeper infiltration compared with 0.5 min (P < 0.05). After 1-min application, PD was significantly lower than 5 min (P < 0.05), PD/LD(max) did not differ from all other groups (P > 0.05). Natural noncavitated proximal lesions in primary molars were deeply infiltrated after 1-min application in vitro. For deeper lesions, however, more consistent results were obtained after 3 min.

Validity of MicroCT for in vitro detection of proximal carious lesions in primary molars

ObjectiveThis study aimed to validate the MicroCT for detection of proximal carious lesions in primary molars, using histology as the gold standard. MethodsForty-eight proximal surfaces of primary molars were examined. Two calibrated examiners conducted the examinations independently. Proximal surfaces were visually scored, using ICDAS. Bitewing radiographs, Micro-CT and histological analyses used caries scores: 0=sound; 1=outer enamel; 2=inner enamel; 3=not spread dentine; 4=outer dentine; 5=inner dentine. Axial and sagital images were used for Micro-CT analysis, whilst for histology, tooth sections (400μm) were analyzed stereomicroscopically (×15). ResultsInter-examiner agreement ranged from 0.87 to 0.93 kappa coefficient (k). Histological analysis revealed a frequency of sound tooth surfaces (18.8%) enamel carious lesions (E1) (48%) and dentine carious lesions (D1) (33.3%). MicroCT showed high correlation with histology (rs0.88). At both diagnostic thresholds (E1 and D1), sensitivity and accuracy were higher for MicroCT. Inter-device agreement between MicroCT and histology was k=0.81. No difference was found between MicroCT and histology as gold standards for detecting carious lesions using ICDAS. ConclusionMicroCT can be used as a gold standard for detecting carious lesions in proximal surfaces in primary molars.

The dilemma of selecting suitable proximal carious lesions in primary molars for restoration using ART technique.

To determine the examiner's accuracy in selecting proximal carious lesions in primary molars for restoration using the atraumatic restorative treatment (ART) approach. Intervention study. CLINICAL SETTING AND PARTICIPANTS: A total of 804 six to eight year-olds from 30 rural schools in Kenya participated in the study. Three examiners selected a total of 1,280 suitable proximal carious lesions in primary molars after examining 6,002 children from 30 schools randomly selected out of 142 schools in two divisions. Seven operators randomly paired on a daily basis with eight assistants restored the lesions. An explanation was provided for any cavity that was not restored. Pre-and post-operative radiographs of the cavities were also taken for evaluation. The examiner's choice of suitable proximal cavities restorable using the ART approach was related to the decision made to either restore or not during the operative stage. The radiographic findings of the selected cavities were also compared to the decision made by the operator. The results obtained were used to determine the examiner's accuracy in selecting suitable proximal cavities for restoration using the ART approach. The majority of the children recruited in the study were excluded due to absenteeism, pulpal-exposure or anxiety during the operative stage. Only 804 children received one restoration in their primary molars. The examiner's accuracy in selecting suitable ART-restorable cavities clinically was 94.9% and based on radiographic analysis was 91.7%. A trained and diligent examiner has a very good chance of selecting proximal carious lesions restorable with the use of ART approach, without the threat of dental pulpal-involvement during the excavation of caries.

COMPARATIVE EVALUATION OF REMINERALISATION POTENTIAL, SURFACE STRUCTURE AND ADHESION BETWEEN GLASS IONOMER AND CALCIUM HYDROXIDE IN PRIMARY TEETH – AN IN VIVO STUDY

The objective of the clinical study is to compare the remineralisation potential of Fuji IX with Dycal at different time intervals. 55 children in the age group of 9–13 years were selected with class I caries lesions in primary molars. Teeth with no obvious clinical signs and symptoms and a minimum dentine thickness of 0.5 to 1mm and no radiographic changes were selected. Teeth were divided into three groups - control and two experimental groups. The mineral content analysis was done with the help of EDAX. The minerals analysed were Sodium, Magnesium, Aluminium, Silica, Phosphorus, Chlorine, Calcium. Teeth in the control group showed lowest mineral content. In the experimental group Fuji IX demonstrated better remineralization potential than Dycal.

Accuracy of direct digital radiography for detecting occlusal caries in primary teeth compared with conventional radiography and visual inspection: anin vitrostudy

the diagnosis of caries lesions is still a matter of concern in dentistry. The diagnosis of dental caries by digital radiography has a number of advantages over conventional radiography; however, this method has not been explored fully in the field of paediatric dentistry. This in vitro research evaluated the accuracy of direct digital radiography compared with visual inspection and conventional radiography in the diagnosis of occlusal caries lesions in primary molars. 50 molars were selected and evaluated under standardized conditions by 2 previously calibrated examiners according to 3 diagnostic methods (visual inspection, conventional radiography and direct digital radiography). Direct digital radiographs were obtained with the Dixi3 system (Planmeca, Helsinki, Finland) and the conventional radiographs with InSight film (Kodak Eastman Co., Rochester, NY). The images were scored and a reference standard was obtained histologically. The interexaminer reliability was calculated using Cohen's kappa test and the specificity, sensitivity and accuracy of the methods were calculated. examiner reliability was good. For lesions limited to the enamel, visual inspection showed significantly higher sensitivity and accuracy than both radiographic methods, but no significant difference was found in specificity. For teeth with dentinal caries, no significant differences were found for any parameter when comparing visual and radiographic evaluation. although less accurate than the visual method for detecting caries lesions confined to the enamel, the direct digital radiographic method is as effective as conventional radiographic examination and visual inspection of primary teeth with occlusal caries when the dentine is involved.

In vitro ability of a laser fluorescence device in quantifying approximal caries lesions in primary molars

Objectives This in vitro study aimed at evaluating the ability of Laser Fluorescence device (LFpen) in quantifying approximal caries lesions in primary molars. Methods Two examiners assessed 123 approximal surfaces of primary molars using the DIAGNOdent pen (LFpen). Surfaces were determined to be either sound with white-spot lesions or have small cavitations. After sectioning, lesion depth was determined through polarized light microscopy. The intra-/inter-examiner agreement was calculated using intraclass correlation coefficient (ICC) and Bland–Altman analyses. Furthermore, Spearman correlation coefficients ( Rs) were calculated between LFpen readings and lesion depth. Results Correlation between LFpen values and lesion depth was low for both examiners ( Rs = 0.36 and 0.51), especially when cavitated lesions were excluded from the analysis ( Rs = 0.22 and 0.40). For all surfaces, ICC revealed intra- and inter-examiner reproducibility values of 0.75 and 0.63, respectively, but when only non-cavitated surfaces were analyzed, these values decreased (0.41 and 0.33, respectively). Conclusions LFpen readings present low correlation with approximal caries lesion depth and low reproducibility, especially in white-spot lesions. Therefore, the device could not be a suitable method for monitoring non-cavitated approximal caries lesion in primary molars.

Self–Report of Pain in Children Treated According to the Atraumatic Restorative Treatment and the Conventional Restorative Treatment – A Pilot Study

To compare the level of pain among children treated according to the Atraumatic Restorative Treatment (ART) and the Conventional Restorative Treatment (CRT). Forty children of both genders, 4- to 7-years old, presenting Class I cavitated dentin lesions in primary molars were randomly allocated to 2 groups. One group (CRT) received conventional restorative treatment using rotary instruments, while in the other one (ART) hand instruments were used to perform the restorations. All children were treated by the same operator A high-viscosity glass-ionomer cement (Fuji IX) was used to restore the teeth in both groups. Children's pain was measured at the end of the first restorative treatment session using the Wong-Baker FACES Pain Rating Scale (dependent variable). Age, gender, treatment time and treatment group were independent variables. ANOVA and ANCOVA tests were used to analyze the data. The CRT procedure took longer than the ART procedure (p < 0.001). Children from the ART group reported less pain than those from the CRT group (p = 0.0037). Four year olds reported more pain than 5- to 7-year olds (p < 0.0001) in both groups. Restorations placed using ART were less time consuming, children felt less pain when the ART approach was used, and younger children (4-years) reported more pain than the older ones for both restorative treatments.

The hall technique

The contemporary view of caries management focuses on treating carious lesions using less invasive treatment options. The Hall Technique is an innovative, less invasive, operative management option, in which preformed metal crowns (PMCs) are used to seal carious lesions with dentin involvement in primary molars using a glass ionomer luting cement. Thus, removal of carious tissue, tooth preparation, or the use of local anesthesia are not required for the Hall Technique. The PMCs are simply pushed over the tooth, to isolate and seal the carious lesions from the oral cavity, resulting in reduction of the nutrient supply and consequently carious lesion arrest. This makes the Hall Technique a technically simple procedure to perform, in terms of clinical skills, and is well accepted by dentists, children, and their parents. However, it should not be considered as a quick solution to the problem of treating all carious primary molars in children who are unable to cooperate with more invasive treatment. For success, the Hall Technique requires careful case selection, precise carious lesion and pulpal diagnosis, good patient management, and parental cooperation. The Hall Technique is an effective treatment option for management of asymptomatic dentin carious lesions in primary molars with long-term high success rates and is, with a strong evidence base, recommended as part of our armamentarium for everyday use in pediatric dentistry.

When Primary Molar Lesions are Cavitated into Dentin, Glass Ionomer has Similar 2-Year Survival to Resin Composite as a Restorative Material When Using the “ART” Technique

A Clinical Evaluation of Resin-Based Composite and Glass Ionomer Cement Restorations Placed in Primary Teeth Using the ART Approach: Results at 24 Months Ersin NK, Candan U, Aykut A, Oncag O, Eronat C, Kose T. J Am Dent Assoc 2006;137(11):1529-36 1 To evaluate the 24-month performance of a high-viscosity glass ionomer restorative material and a packable resin-based composite with dentin bonding system in restorations placed into primary molars using the “atraumatic restorative treatment” (ART) technique. Both materials (GIC [glass ionomer cement] and resin-based composite/bonding system) were supplied by the manufacturer of the GIC material. No additional source of funding was identified. Split Mouth Paired Design with Random Assignment to Side of Mouth

Clinical evaluation of glass-ionomer tunnel restorations in primary molars: 36 months results

The purpose of this study was to clinically examine the efficacy of tunnel preparations in primary molars restored with glass-ionomer cement during a 36-month observation period. A total of 233 tunnel restorations were placed in primary molars of 203 patients aged 6-10 years. Restorations were evaluated after 12, 24 and 36 months using the modified USPHS criteria for secondary caries, marginal discolouration, marginal adaptation and anatomic form. The Alpha+Bravo score (except for caries) and absence of clinical signs of endodontic complications was considered as a clinical success. At the end of the 36-month experimental period, the cumulative survival rate of tunnel restorations in primary molars was 72 per cent. The main reasons for failure were endodontic complications (46 per cent of the failures), secondary caries (31 per cent of the failures) and marginal ridge fractures (19 per cent of the failures). The tunnel preparation filled with reinforced restorative glass-ionomer cement is a suitable treatment for minimal proximal caries lesions in primary molars.

Elastomeric impression as a diagnostic method of cavitation in proximal dentin caries in primary molars

The purpose of this study was to validate the elastomeric impression after temporary tooth separation as a method of cavitation detection in proximal caries lesions in primary molars with outer half dentin radiolucency. Fifty-one children (4-10 years old), presenting radiolucency in the outer half of the dentin at the proximal surfaces of primary molars and proximal anatomic contact with the adjacent tooth (without restoration/cavitated caries lesion) were enrolled in the study. Temporary tooth separation was performed with an orthodontic rubber ring placed around the contact point during 2-3 days. Thereafter, impression of the proximal surfaces was made. The elastomeric impressions were classified as "non-cavitated" or "cavitated" surfaces. Visual inspection after tooth separation was considered as the gold standard. Examiner reliability of visual inspection after tooth separation was determined (kappa 0.92). Impression examination was repeated every 5 participants to evaluate the reproducibility of the method. The frequency of cavitated lesions was 65%, and 67% of those were inactive. Sensitivity, specificity, positive and negative predictive values were 0.88% (95%CI 0.73-0.95), 0.89% (95%CI 0.67-0.97), 0.94% (95%CI 0.79-0.98) and 0.80% (95%CI 0.58-0.92), respectively. Impression examination showed total agreement regarding cavitation. The evaluation of elastomeric impression after tooth separation is a useful clinical resource in cavitation detection for clinicians and researchers when visual inspection is doubtful.

Perceived dental anxiety among schoolchildren treated through three caries removal approaches

Objectives:The aim of the investigation was to test the differences in the perceived level of dental anxiety among children treated restoratively using the Atraumatic Restorative Treatment (ART) approach, the traditional restorative (TRA) approach and ART aided with a chemomechanical caries removal gel (ART plus).Methods:The study subjects were 6-7-year-old children. TRA was compared to ART in a clinical setting after children had seen a dentist twice (Group A), ART was compared to 'ART plus' in a clinical setting after children had seen a dentist once (Group B) and ART was applied outside the clinic on school premises (Group C). The treatments were carried out in Class II cavitated dentine lesion in primary molars. Dental anxiety was measured using the Venham Picture Test (VPT). Three-way analysis of variances and interaction was applied to test for treatment approach, gender and operator effects on the mean VPT scores.Results:There was no statistically significant difference (p=0.80) observed between the mean VPT scores for the traditional approach and those for the ART approach and between ART with and without a chemomechanical caries removal gel (p=0.07). Children in Group A had lower mean VPT scores than children in Group B (p=0.02) and Group C (p<0.00001) when treated using the ART approach by the same two operators.Conclusions:The level of dental anxiety was low. There was no difference in level of dental anxiety observed in children treated with ART in comparison to the traditional restorative approach, and between children treated with ART with and without a chemomechanical caries removal gel. The treatment environment and prepatory visits may be factors determining the level of dental anxiety in children treated through the ART approach only.

Restorative Treatment Decisions for Deep Proximal Carious Lesions in Primary Molars

To assess clinicians' individual variables that might influence decision-making for the restoration of deep proximal carious lesions in primary molars. A pre-coded questionnaire that sought participants' treatment choices for a deeply carious second mandibular primary molar, as depicted in a simulated periapical radiograph, along with a specific clinical scenario, was distributed among a random sample of 157 dentists and 15 paediatric dentists. Participants were asked to answer questions. After combining the pulpotomy and pulpectomy treatment choices under a 'pulp therapy' category, a binary dependent variable was constructed. Logistic regression of the ratio of the participants who would restore the questioned tooth by a method in question, was run. A total of 155 dentists (116 males and 39 females) completed the survey, giving a response rate of 90%. Of these 53% of dentists recommended pulpotomy followed by definitive restoration and 39% recommended removal of caries and restoration without pulp therapy. In the logistic regression model, males and graduates of English language undergraduate dental programs had higher probabilities of restoring without prior pulp therapy (p<0.03 and p<0.02, respectively). Compared with graduates of Asian programs, dentists who graduated from Eastern Europe and the Middle East, showed lower likelihoods of restoring the tooth without prior pulp therapy (p<0.01 and p<0.004, respectively). Dentists who treated an average of 6-16 child patients during a week had a lower probability of restoring the tooth without prior pulp therapy than those who were not currently involved in treating children (p<0.01). No other measured variables were associated with participant's treatment choices. The lack of agreement among dentists regarding their optimal treatment recommendations for deep proximal carious lesions appears to be due mainly to inter-individual, educational, training and practice characteristic factors.

Microbiological Assessment of Occlusal Brown-Spot Lesions in Primary Molars

Conventional cultural methods were used to compare the plaque flora and the level of infection of the dentine underlying 51 occlusal brown-spot lesions and 21 sound occlusal sites on the primary dentition. Freshly extracted primary molar teeth were used, and occlusal brown-spot lesions and sound occlusal sites were identified using laser fluorescence (LF) and clinical visual methods. A standardized plaque sample was taken from each site, and an LF score was recorded for one discrete site per tooth. The teeth were carefully opened at each predetermined site to determine the clinical status of the underlying dentine, and samples were collected using a sterile bur. The microbiota of the plaque and dentine samples were enumerated and identified. The mean LF scores for the sound sites and brown-spot lesions were 1.2 and 30.5 (p < 0.001), and all the sound sites exhibited hard sound dentine, but 6 out of 51 brown spots exhibited softened dentine. Overall there was no significant (p > 0.1) difference between the level of infection of the dentine of the sound and brown-spot sites, although some sites in the brown-spot lesions yielded high numbers of bacteria. However, the numbers of bacteria as log₁₀(CFU per sample + 1) ± SE recovered from the plaque above the brown-spot lesions were significantly greater than above the sound sites, i.e. 2.89 ± 0.24 and 0.89 ± 0.33, respectively. These data indicate that brown-spot lesions may be more plaque retentive than sound sites and that they are either arrested or arresting lesions, which may require preventive intervention.