Comparison Of The Adaptability Of Two Fissure Sealants In Various Tooth Fissure Morphology Patterns: An In Vitro Experimental Study.

BACKGROUND: This study was conducted to compare the adaptation of resin-based sealants with that of Resin modified glass ionome-based sealants in various tooth fissure morphologies. METHODS: It was an in vitro experimental study done at the Dow University and NED University, Karachi, Pakistan. Ten extracted human molars were randomly assigned to two groups, (n=5) each. Fissure sealant material (Resin based sealant or resin modified glass ionomer-based sealant) was applied on the occlusal surface of the tooth according to manufacturer's recommendations. Specimens were thermocycled and then sectioned into three longitudinal parts in the bucco- lingual direction. Specimens were examined using scanning electron microscope for the adaptation of the sealant in the occlusal fissure. Mann-Whitney -U test and Kruskall-Wallis test were applied to compare the adaptability scores of sealant materials in the tooth fissure. Level of significance was kept at 0.05. RESULTS: There were no significant differences in the adaptability scores among U-shaped (p-value=0.35), V-shaped (p-value=0.89), IK-shaped (p-value=0.52), I-shaped (p-value- =0.41) and Y-shaped (p-value=1.00) fissure patterns. Similarly, there were no significant differences observed between the resin-based sealant (p-value=0.95) versus RMGIC based sealant (p-value=0.63) for the adaptability scores in various tooth fissure morphologies. CONCLUSIONS: No significant difference was found between resin-based sealants and resin modified glass ionomerbased sealants for the adaptation in various tooth fissure patterns.

Modelling of stress distribution and fracture in dental occlusal fissures.

The aim of this study was to investigate the fracture behaviour of fissural dental enamel under simulated occlusal load in relation to various interacting factors including fissure morphology, cuspal angle and the underlying material properties of enamel. Extended finite element method (XFEM) was adopted here to analyse the fracture load and crack length in tooth models with different cusp angles (ranging from 50° to 70° in 2.5° intervals), fissural morphologies (namely U shape, V shape, IK shape, I shape and Inverted-Y shape) and enamel material properties (constant versus graded). The analysis results showed that fissures with larger curved morphology, such as U shape and IK shape, exhibit higher resistance to fracture under simulated occlusal load irrespective of cusp angle and enamel properties. Increased cusp angle (i.e. lower cusp steepness), also significantly enhanced the fracture resistance of fissural enamel, particularly for the IK and Inverted-Y shape fissures. Overall, the outcomes of this study explain how the interplay of compositional and structural features of enamel in the fissural area contribute to the resistance of the human tooth against masticatory forces. These findings may provide significant indicators for clinicians and technicians in designing/fabricating extra-coronal dental restorations and correcting the cuspal inclinations and contacts during clinical occlusal adjustment.

[The influence of teeth morphology on bioelectrical activity of masticatory muscles]. / Vliianie morfologii zubov na bioélektricheskuiu aktivnost' zhevatel'nykh myshts.

The aim of the study was to reveal correlation of dental morphology and bioelectric activity of masticatory muscles. The study included 76 young adults (47.4% females and 52.6% males) divided in 3 groups according to dental morphology features: intact teeth (26 patients), dental decay in fissures with intact cusps (25 patients), pronounced dental decay with varying degree of crown destruction (25 patients). Electromyography (EMG) was used to document the bioelectric activity (BEA) of temporal and masticatory muscles. The study showed high level of correlation of destructive teeth changes with BEA of masticatory muscles. Intragroup correlation proved direct link of BEA to the number of decayed teeth. EMG activity differed significantly between groups 2 and 3. There was no statistically significant difference between groups 3 and 1 mostly because of high variability of BEA in group 3. Relative activity of temporal and masticatory muscles increased in groups 2 and 3 by 2 and 4% and 38 and 19%, correspondingly. There was no significant impact of gender or emotional status on masticatory muscles BEA.

External and internal resin infiltration of natural proximal subsurface caries lesions: A valuable enhancement of the internal tunnel restoration.

OBJECTIVE: The aim of this ex-vivo study was to evaluate both the external and the internal penetration ability of a resin infiltrant into natural proximal and macroscopically intact white spot lesions, and to merge this approach with the internal tunnel preparation concept. METHOD AND MATERIALS: 20 premolars and 20 molars with proximal subsurface lesions (ICDAS, code 2) and respective radiographic lesion depths extending into the middle third of dentin (D2 lesions) were selected and divided into two groups. Treatment needs were confirmed using digital imaging fiber-optic transillumination and laser fluorescence. Deproteinization (NaOCl; 2%) followed, and lesions of Group 1 (control; n = 20) were etched (HCl; 15%) and externally infiltrated (Icon). Accordingly, the specimens of Group 2 (n = 20) were treated with the resin infiltrant from external; then, internal Class I tunnels were prepared, lesions were internally infiltrated (Icon), and the occlusal cavities were restored (G-ænial Flo X) after etching (H3PO4 gel; 40%). Teeth were cut perpendicular to the proximal lesion surfaces, and percentage infiltrations were analyzed using confocal laser microscopy and a dedicated image manipulation program (GIMP). RESULTS: Regarding the external infiltration, no differences between both groups were detected (P = .114; Mann-Whitney). Additional internal application of the resin infiltrant significantly increased the percentage amount of enamel lesion infiltration (P < .0001; Wilcoxon). CONCLUSION: External and internal infiltration seem to complement the internal tunnel approach, thus remediating the drawbacks of the latter by occluding and stabilizing the porous areas of the proximal caries lesion, and preserving both the marginal ridge and the proximal contact area.

Near-IR and CP-OCT imaging of suspected occlusal caries lesions.

INTRODUCTION: Radiographic methods have poor sensitivity for occlusal lesions and by the time the lesions are radiolucent they have typically progressed deep into the dentin. New more sensitive imaging methods are needed to detect occlusal lesions. In this study, cross-polarization optical coherence tomography (CP-OCT) and near-IR imaging were used to image questionable occlusal lesions (QOC's) that were not visible on radiographs but had been scheduled for restoration on 30 test subjects. METHODS: Near-IR reflectance and transillumination probes incorporating a high definition InGaAs camera and near-IR broadband light sources were used to acquire images of the lesions before restoration. The reflectance probe utilized cross-polarization and operated at wavelengths from 1,500 to 1,700 nm where there is an increase in water absorption for higher contrast. The transillumination probe was operated at 1,300 nm where the transparency of enamel is highest. Tomographic images (6 × 6 × 7 mm3 ) of the lesions were acquired using a high-speed swept-source CP-OCT system operating at 1,300 nm before and after removal of the suspected lesion. RESULTS: Near-IR reflectance imaging at 1,500-1,700 nm yielded significantly higher contrast (P < 0.05) of the demineralization in the occlusal grooves compared with visible reflectance imaging. Stains in the occlusal grooves greatly reduced the lesion contrast in the visible range yielding negative values. Only half of the 26 lesions analyzed showed the characteristic surface demineralization and increased reflectivity below the dentinal-enamel junction (DEJ) in 3D OCT images indicative of penetration of the lesion into the dentin. CONCLUSION: This study demonstrates that near-IR imaging methods have great potential for improving the early diagnosis of occlusal lesions. Lasers Surg. Med. 49:215-224, 2017. © 2017 Wiley Periodicals, Inc.

Micro-filled resin infiltration of fissure caries lesions in vitro.

OBJECTIVES: The aim of this in vitro study was to evaluate three treatment modalities [infiltrant resin (IR), micro-filled infiltrant resin (MFIR), infiltrant-sealant-combination (ISC)] regarding both their abilities to penetrate lesions differing in ICDAS-codes and to fill fissures and cavities. MATERIALS AND METHODS: Extracted human molars (n=90) showing fissure caries lesions with and without cavitations were etched with 15% hydrochloric acid (HCl) that was mixed with abrasives and a 15% HCl-solution (1:1). The etching gel was rubbed for 30s within the fissure and, if eligible, within the cavity using a brush. After this pretreatment an infiltrant (Icon; DMG; IR) or an infiltrant mixed with microfillers (MFIR) was applied. ISC included the application of an infiltrant followed by a fissure sealant (Helioseal; Ivoclar Vivadent) From each tooth slices showing a non-cavitated (based on ICDAS-2) or cavitated lesion part (based on ICDAS-3/5) were prepared. Lesion (LA) and penetration areas (PA) as well as the completeness of fissure and cavity filling were analyzed using dual staining and confocal laser scanning microscopy. RESULTS: Percentage penetration (PP) was calculated as 100×PA/LA. PP [median (25th/75th)] did not differ significantly between IR [95 (86/100)%], MFIR [93 (62/100)%] or ISC [89 (67/97)%] (p>0.05; Kruskal-Wallis test). All three materials filled about 90% of the dimensions of fissures and cavities (p>0.05; Kruskal-Wallis test). CONCLUSION: It can be concluded that MFIR seems to be suitable to fill fissures and cavities like a fissure sealant and that it penetrates fissure caries lesions similarly deep as the conventional infiltrant after an experimental etching regime. CLINICAL SIGNIFICANCE: The MFIR seems to combine advantages of the fissure sealing and the caries infiltration procedure.

Mechanical benefits of conservative restoration for dental fissure caries.

The principle of minimal intervention dentistry (MID) is to limit removal of carious tooth tissue while maximizing its repair and survival potential. The objective of this study is to explore the fracture resistance of a permanent molar tooth with a fissure carious lesion along with three clinical restoration procedures, namely one traditional and two conservative approaches, based upon MID. The traditional restoration employs extensive surgical removal of enamel and dentine about the cavity to eliminate potential risk of further caries development, while conservative method #1 removes significantly less enamel and infected dentine, and conservative method #2 only restores the overhanging enamel above the cavity and leaves the infected and affected dentine as it was. An extended finite element method (XFEM) is adopted here to analyze the fracture behaviors of both two-dimensional (2D) and three-dimensional (3D) modeling of these four different scenarios. It was found that the two conservative methods exhibited better fracture resistance than the traditional restorative method. Although conservative method #2 has less fracture resistance than method #1, it had significantly superior fracture resistance compared to other restorations. More important, after cavity sealing it may potentially enhance the opportunity for remineralization and improved loading bearing capacity and fracture resistance.

Resin infiltration of fissure caries with various techniques of pretreatment in vitro.

The resin infiltration technique might be used for occlusal caries lesions in order to arrest their progression. This in vitro study evaluated the influence of various modifications of the infiltration technique on the penetration abilities of the infiltrant into occlusal lesions. Extracted human molars and premolars (n = 140) with non-cavitated white spot lesions were randomly allocated to 7 groups. As control, specimens were etched with 15% hydrochloric acid (HCl) gel for 120 s and resin infiltrated for 180 s (Icon; DMG). As modification HCl gel reduced in surface tension and viscosity with and without abrasives was applied using 3 different types of brushes either to oscillate or rub the HCl gel onto the enamel surface. The median maximum lesion depth was 1,232 µm (interquartile range 882-1,513). Compared with the control procedure [23% (16/50)] a higher percentage penetration was observed if the HCl gel was mixed with a small amount of abrasives were rubbed into the fissures using a modified brush with stiff bristles that were adjusted to the fissure relief for either 120 s [100% (64/100)] or 30 s [98% (61/100); p < 0.05; Mann-Whitney test]. All other experimental treatments resulted in penetration results in-between. It can be concluded that the use of an abrasive HCl gel in conjunction with a modified brush mostly enhances resin infiltration into fissure caries lesions.

Micro X-ray computed tomography of pits and fissures.

BACKGROUND: Most tooth cavities start to develop inside pits and fissures where brushing, saliva, fluoride toothpaste or mouthwashes have no access. Therefore, 3D morphology of pits and fissures is an important subject to be studied in relation to maintaining proper oral hygiene. OBJECTIVE: This study aimed to present high resolution images of pits and fissures in human teeth using a laboratory-based micro X-ray Computed Tomography (mXCT) and also to present the basic structure evaluation that could be obtained. METHODS: Three human wisdom teeth were examined. Two different set-ups were used in this study achieving resolution of 14.59 µm (Field of View of 14.9 mm) and resolution of 4.43 µm (FOV of 4.5 mm) respectively. Automated segmentation was performed for further evaluation to distinguish between empty space (pits and fissures) and the filled space (enamel). RESULTS: The 3D tomography results demonstrate detailed morphology with accurate dimensions and the locations of the pits and fissures, which is important to investigate the relationship with tooth decay that mostly starts deep inside pits and fissures. CONCLUSIONS: Segmentation from the mXCT imaging of pits and fissures provides obvious visual evidence to help in promotion of oral health and to improve personal tooth care in preventive treatment protocols.

Glass ionomer ART sealant and fluoride-releasing resin sealant in fissure caries prevention--results from a randomized clinical trial.

BACKGROUND: The relative performance of ART sealant and fluoride-releasing resin sealant in preventing fissure caries in permanent molars was compared in a randomized clinical trial conducted in southern China (ClinicalTrials.gov NCT01829334). METHODS: After obtaining ethical approval, healthy schoolchildren who had permanent first molars with occlusal fissures which were sound but deep or presented with only incipient caries were recruited for the study. Included molars were randomly allocated into one of four parallel study groups in units of left/right teeth per mouth. Two of the four groups adopted the methods of ART or fluoride-releasing resin sealant placement while the other two groups adopted the topical fluoride application methods. Fissure status of the molars in each group was evaluated every 6 months. Development of dentine caries and sealant retention over 24 months in the molars in the two sealant-using groups was compared in this report. Outcome on cost-effectiveness of all four groups over 36 months will be reported elsewhere. RESULTS: At baseline, a total of 280 children (383 molars) with mean age 7.8 years were involved for the two sealant groups. After 24 months, 261 children (357 molars) were followed. Proportions of molars with dentine caries were 7.3% and 3.9% in the ART sealant and fluoride-releasing resin sealant groups, respectively (chi-square test, p = 0.171). Life-table survival analysis showed that sealant retention (full and partial) rate over 24 months for the resin sealant (73%) was significantly higher than that (50%) for the ART sealant (p < 0.001). Molar survival (no development of dentine caries) rates in the ART sealant (93%) and fluoride-releasing resin sealant (96%) groups were not significantly different (p = 0.169). Multilevel logistic regression (GEE modeling) accounting for the effects of data clustering and confounding factors confirmed this finding. CONCLUSIONS: Though the retention of fluoride-releasing resin sealant was better than that of the ART sealant, their effectiveness in preventing fissure caries in permanent molars did not differ significantly over 24 months. ART sealants could be a good alternative when and where resources for resin sealant placement are not readily available.

Characteristics, detection methods and treatment of questionable occlusal carious lesions: findings from the national dental practice-based research network.

Questionable occlusal carious lesions (QOC) can be defined as an occlusal tooth surface with no cavitation and no radiographic radiolucencies, but caries is suspected due to roughness, surface opacities or staining. An earlier analysis of data from this study indicates 1/3 of patients have a QOC. The objective of this report has been to quantify the characteristics of these common lesions, the diagnostic aids used and the treatment of QOC. A total of 82 dentist and hygienist practitioner-investigators from the USA and Denmark in the National Dental Practice-Based Research Network participated. When consenting patients presented with a QOC, information was recorded about the patient, tooth, lesion and treatments. A total of 2,603 QOC from 1,732 patients were analyzed. The lesions were usually associated with a fissure, on molars, and varied from yellow to black in color. Half presented with a chalky luster and had a rough surface when examined with an explorer. There was an association between color and luster: 10% were chalky-light, 47% were shiny-dark and 42% were mixtures. A higher proportion of chalky than of shiny lesions were light (22 vs. 9%; p < 0.001). Lesions light in color were less common in adults than in pediatric patients (9 vs. 32%; p < 0.001). Lesions that were chalky and light were more common among pediatric than among adult patients (22 vs. 6%; p < 0.001). This is the first study to investigate characteristics of QOC in routine clinical practice. Clinicians commonly face this diagnostic uncertainty. Determining the characteristics of these lesions is relevant when making diagnostic and treatment decisions.

Comparison of sealant and infiltrant penetration into pit and fissure caries lesions in vitro.

OBJECTIVES: The aim of this in vitro study was to evaluate the penetration of an infiltrant and a sealant, when applied as recommended, into fissure caries lesions. METHODS: The fissure systems of extracted human teeth were classified according to the international caries detection and assessment system (ICDAS, codes: 0, 1, 2). Within each ICDAS-code ten teeth were either etched with 37% H3PO4-gel for 60s and subsequently sealed ('Fissure Sealing'; Helioseal; Ivoclar Vivadent) or etched with 15% HCl-gel for 120s and subsequently infiltrated ('Resin Infiltration'; Icon; DMG). Additionally, ten teeth with ICDAS-code 2 were etched with 37% H3PO4-gel for 120s and infiltrated ('Soft-Etch-Infiltration'). Specimens were cut perpendicular to their surfaces, polished, and confocal microscopic images were obtained. Lesion depths (LDmax) and penetration depths (PDmax) were measured and percentage penetration was calculated as PPmax=PDmax/LDmax×100. RESULTS: Baseline LDmax [median (interquartile range)] for ICDAS-code 2 lesions was 1192 (805-1512)µm. In ICDAS-code 2 lesions PPmax was significantly higher for specimens treated with 'Resin Infiltration' [41 (30-78)%] compared to 'Soft-Etch-Infiltration' [11 (0-21)%] or 'Fissure Sealing' [5 (0-9)%] (p<0.05; Mann-Whitney test). PPmax did not differ significantly between groups in ICDAS-code 0 and 1 lesions (p>0.05). CONCLUSION: The fissure sealant when applied after etching with H3PO4-gel only penetrates superficially into non-cavitated fissure caries lesions. Penetration of an infiltrant is superior in particular after etching with HCl-gel. CLINICAL SIGNIFICANCE: Compared with sealing, infiltration of fissure caries lesions leads to more deeply infiltrated lesions, which might in turn result in superior abilities to hamper caries progression.

Irregularities below the enamel-dentin junction may predispose for fissure caries.

This study investigated the structure of the fissure fundus on occlusal surfaces with respect to the detection of possible irregularities below the enamel-dentin junction (EDJ). Occlusal surfaces were examined by micro-computed tomography (µCT). In total, 203 third molars with clinically sound occlusal fissures or non-cavitated lesions were selected. All specimens were scanned with µCT. Subsequently, each tooth was sectioned, and each slice was investigated by stereomicroscopy. In 7 of 203 molars (3.4%), demarcated radiolucencies below the EDJ were detected by µCT. These defects were obviously of non-carious origin, because the µCT images revealed no gradient of demineralization in the dentin. In all cases, a direct pathway between the oral cavity and the dentin was evident. The comparison of the µCT sites with conventional histological images also revealed defects in the dentin. These results demonstrate that demarcated radiolucencies below the EDJ may not necessarily be caries lesions according to µCT images and may be classified as possible developmental irregularities. To avoid misinterpreting µCT data, dental researchers should carefully consider this condition when analyzing µCT images. The clinical significance of this finding is that these defects may predispose molar teeth to early-onset caries in occlusal pits and fissures.

Randomized trial on fluorides and sealants for fissure caries prevention.

To investigate the effectiveness of topical fluorides in preventing fissure caries, we conducted a randomized controlled trial with parallel groups. In total, 501 children (1,539 molars, 3,078 sites), mean age 9.1 years, who had at least one sound permanent first molar with deep fissures or fissures with signs of early caries were recruited. They were randomly allocated among four groups: (1) resin sealant, single placement; (2) 5% NaF varnish, semi-annual application; (3) 38% silver diamine fluoride (SDF) solution, annual application; and (4) placebo control. Follow-up examinations were conducted every 6 months by a masked examiner. After 24 months, 485 children (97%) were examined. Proportions of pit/fissure sites with dentin caries in the sealant, NaF, SDF, and control groups were 1.6%, 2.4%, 2.2%, and 4.6%, respectively. A multi-level logistic regression analysis accounting for the effects of data clustering and confounding factors showed that fissures in any of the three treatment groups had significantly lower risks of carious cavity development into dentin than did controls (p < 0.05). We concluded that placement of resin sealant, semi-annual application of NaF varnish, and annual application of SDF solution are all effective in preventing pit and fissure caries in permanent molars (ClinicalTrials.gov number CT01446107).

Dental caries and first permanent molar pit and fissure morphology in 7- to 8-year-old children in Wuhan, China.

To obtain the caries experience and, plaque accumulation severity and pit and fissure morphology in first permanent molars in 7-8 children in Wuhan, as a reasonable prediction of caries risk and preventive attention in the future, a convenient sample of five primary schools in the vicinity of the Wuhan University School and Hospital of Stomatology was drawn. Two calibrated examiners orally examined all present grade 2 children in the classroom, using standard caries plaque and tooth morphology criteria. Dental caries was scored at enamel (D(2)) and dentine (D(3)) for tooth and surface level. Independent variables were age, gender and school. Data analysis used analysis of variance and t-test. The sample comprised 1 043 7- and 8-year-olds. The prevalence of dental caries in permanent dentition was 8.7% and in primary dentition, 68.7%. Mean Decayed, Missing, Filled Teeth/S (DMFT/S) scores were 0.11 and 0.14, respectively. Mean dmft/s scores were 2.8 and 5.0. The d-component constituted 75% of the d(3)mft index, while enamel carious lesions constituted 36% of the total number of carious lesions (d(2,3)-component). Prevalence of medium and deep pits and fissures was 84.6%. Prevalence of medium and severe plaque accumulation was 67.4%. Prevalence of dental caries in the deciduous and permanent dentitions of 7- to 8-year-old children was high. Deep pits and fissures in high caries risk children should be sealed.

Performance of laser fluorescence for the detection of enamel caries in non-cavitated occlusal surfaces: clinical study with total validation of the sample.

PURPOSE: To evaluate the clinical performance of a laser fluorescence device in detecting enamel caries in non-cavitated occlusal surfaces. METHODS: The sample included 96 first and second permanent molars, selected according to the criteria of Ekstrand: 44 not suspected of having dentin caries (score: 0-2) and 52 under suspicion (score: 3-4). Once measured by laser fluorescence, all teeth were validated by fissurotomy (gold standard). To avoid ethical questions, the 44 teeth (score: 0-2) used were to serve as abutments for a fixed dental prostheses. Following fissurotomy, the 52 teeth with suspected caries were treated with resin composite restorations. Kruskall-Wallis statistical analysis (P<0.05) was used. RESULTS: Laser fluorescence showed an area under the Receiver Operating Characteristic (ROC) curve of Az = 0.803 for enamel caries. The cut-off point with the highest sensitivity and specificity was 15, with a sensitivity and specificity of 0.97 and 0.63, respectively. Values under 10 indicated healthy teeth.

The performance of conventional and fluorescence-based methods for occlusal caries detection: an in vivo study with histologic validation.

BACKGROUND: The authors conducted an in vivo study to determine clinical cutoffs for a laser fluorescence (LF) device, an LF pen and a fluorescence camera (FC), as well as to evaluate the clinical performance of these methods and conventional methods in detecting occlusal caries in permanent teeth by using the histologic gold standard for total validation of the sample. METHODS: One trained examiner assessed 105 occlusal surfaces by using the LF device, LF pen, FC, International Caries Detection and Assessment System (ICDAS) criteria and bitewing (BW) radiographic methods. After tooth extraction, the authors assessed the teeth histologically. They determined the optimal clinical cutoffs by means of receiver operating characteristic curve analysis. RESULTS: The specificities and sensitivities for enamel and dentin caries detection versus only dentin caries detection thresholds were 0.60 and 0.93 and 0.77 and 0.52 (ICDAS), 1.00 and 0.29 and 0.97 and 0.44 (BW radiography), 1.00 and 0.85 and 0.77 and 0.81 (LF device), 0.80 and 0.89 and 0.71 and 0.85 (LF pen) and 0.80 and 0.74 and 0.49 and 0.85 (FC), respectively. The accuracy values were higher for ICDAS, the LF device and the LF pen than they were for BW radiography and the FC. CONCLUSIONS: The clinical cutoffs for sound teeth, enamel carious lesions and dentin carious lesions were, respectively, 0 through 4, 5 through 27 and 28 through 99 (LF device); 0 through 4, 5 through 32 and 33 through 99 (LF pen); and 0 through 1.2, 1.3 and 1.4 through 5.0 (FC). The ICDAS, the LF device and the LF pen demonstrated good performance in helping detect occlusal caries in vivo. The ICDAS did not seem to perform as well at the D(3) threshold (histologic scores 3 and 4) as at the D(1) threshold (histologic scores 1-4). BW radiography and the FC had the lowest performances in helping detect lesions at the D(1) and D(3) thresholds, respectively. CLINICAL IMPLICATIONS: Occlusal caries detection should be based primarily on visual inspection. Fluorescence-based methods may be used to provide a second opinion in clinical practice.

Heritable patterns of tooth decay in the permanent dentition: principal components and factor analyses.

BACKGROUND: Dental caries is the result of a complex interplay among environmental, behavioral, and genetic factors, with distinct patterns of decay likely due to specific etiologies. Therefore, global measures of decay, such as the DMFS index, may not be optimal for identifying risk factors that manifest as specific decay patterns, especially if the risk factors such as genetic susceptibility loci have small individual effects. We used two methods to extract patterns of decay from surface-level caries data in order to generate novel phenotypes with which to explore the genetic regulation of caries. METHODS: The 128 tooth surfaces of the permanent dentition were scored as carious or not by intra-oral examination for 1,068 participants aged 18 to 75 years from 664 biological families. Principal components analysis (PCA) and factor analysis (FA), two methods of identifying underlying patterns without a priori surface classifications, were applied to our data. RESULTS: The three strongest caries patterns identified by PCA recaptured variation represented by DMFS index (correlation, r = 0.97), pit and fissure surface caries (r = 0.95), and smooth surface caries (r = 0.89). However, together, these three patterns explained only 37% of the variability in the data, indicating that a priori caries measures are insufficient for fully quantifying caries variation. In comparison, the first pattern identified by FA was strongly correlated with pit and fissure surface caries (r = 0.81), but other identified patterns, including a second pattern representing caries of the maxillary incisors, were not representative of any previously defined caries indices. Some patterns identified by PCA and FA were heritable (h(2) = 30-65%, p = 0.043-0.006), whereas other patterns were not, indicating both genetic and non-genetic etiologies of individual decay patterns. CONCLUSIONS: This study demonstrates the use of decay patterns as novel phenotypes to assist in understanding the multifactorial nature of dental caries.

In vitro evaluation of the Spectra early caries detection system.

OBJECTIVE: The goal of this study was to perform an in vitro evaluation of the Spectra, a new caries detector that uses light-induced fluorescence of healthy tooth structure and bacterial pigments to optically detect caries. The Spectra generates a storable color map image of examined tooth surfaces which shows areas of enamel and dentin caries. In this study, Spectra readings of occlusal surfaces were compared to clinical, radiographic, and histological assessments of caries. METHODS: Two examiners evaluated 41 extracted molars. The teeth were radiographed and then visually assessed. The International Caries Detection and Assessment System (ICDAS) was used to classify the extent of caries. The teeth were then sectioned and assigned a histological score based on the extension of caries into enamel or dentin. RESULTS: Teeth lacking radiographic caries had a mean Spectra reading of 1.5. Teeth having radiographic caries had a mean Spectra reading of 2.0. This difference was statistically significant. In general, higher ICDAS scores were associated with higher Spectra readings. Teeth with histologically evident deep dentin caries had significantly higher Spectra readings than intact teeth or teeth with superficial enamel demineralization. Spectra assessment of occlusal caries agrees with clinical and radiographic methods. CONCLUSION: Spectra images illustrate the full spectrum of caries severity, from enamel demineralization to dentin decay. The Spectra is a promising technology for the diagnosis and for monitoring the progression of occlusal caries.