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Objectives: This study aimed to develop and evaluate a fully automated method for visualizing and measuring tooth wear progression using pairs of intraoral scans (IOSs) in comparison with a manual protocol., Methods: Eight patients with severe tooth wear progression were retrospectively included, with IOSs taken at baseline and 1-year, 3-year, and 5-year follow-ups. For alignment, the automated method segmented the arch into separate teeth in the IOSs. Tooth pair registration selected tooth surfaces that were likely unaffected by tooth wear and performed point set registration on the selected surfaces. Maximum tooth profile losses from baseline to each follow-up were determined based on signed distances using the manual 3D Wear Analysis (3DWA) protocol and the automated method. The automated method was evaluated against the 3DWA protocol by comparing tooth segmentations with the Dice-Sørensen coefficient (DSC) and intersection over union (IoU). The tooth profile loss measurements were compared with regression and Bland-Altman plots. Additionally, the relationship between the time interval and the measurement differences between the two methods was shown., Results: The automated method completed within two minutes. It was very effective for tooth instance segmentation (826 teeth, DSC = 0.947, IoU = 0.907), and a correlation of 0.932 was observed for agreement on tooth profile loss measurements (516 tooth pairs, mean difference = 0.021mm, 95% confidence interval = [-0.085, 0.138]). The variability in measurement differences increased for larger time intervals., Conclusions: The proposed automated method for monitoring tooth wear progression was faster and not clinically significantly different in accuracy compared to a manual protocol for full-arch IOSs., Clinical Significance: General practitioners and patients can benefit from the visualization of tooth wear, allowing quantifiable and standardized decisions concerning therapy requirements of worn teeth. The proposed method for tooth wear monitoring decreased the time required to less than two minutes compared with the manual approach, which took at least two hours., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest and that they are solely responsible for the contents of this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: The aim of this study was to evaluate the accuracy of a combined approach based on an isotopological remeshing and statistical shape analysis (SSA) to capture key anatomical features of altered and intact premolars. Additionally, the study compares the capabilities of four Machine Learning (ML) algorithms in identifying or simulating tooth alterations., Methods: 113 premolar surfaces from a multicenter database were analyzed. These surfaces were processed using an isotopological remeshing method, followed by a SSA. Mean Euclidean distances between the initial and remeshed STL files were calculated to assess deviation in anatomical landmark positioning. Seven anatomical features were extracted from each tooth, and their correlations with shape modes and morphological characteristics were explored. Four ML algorithms, validated through three-fold cross-validation, were assessed for their ability to classify tooth types and alterations. Additionally, twenty intact teeth were altered and then reconstructed to verify the method's accuracy., Results: The first five modes encapsulated 76.1% of the total shape variability, with a mean landmark positioning deviation of 10.4 µm (±6.4). Significant correlations were found between shape modes and specific morphological features. The optimal ML algorithms demonstrated high accuracy (>83%) and precision (>86%). Simulations on intact teeth showed discrepancies in anatomical features below 3%., Conclusion: The combination of an isotopological remeshing with SSA showed good reliability in capturing key anatomical features of the tooth., Clinical Significance: The encouraging performance of ML algorithms suggests a promising direction for supporting practitioners in diagnosing and planning treatments for patients with altered teeth, ultimately improving preventive care., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives: Tooth wear causes irreversible cumulated surface loss and already occurs at a young age. Therefore, the objective of this clinical prospective observational study was to monitor the occlusal surface of a mandibular first molar in young adults for a period of 24 months. Furthermore, potential aetiological factors obtained by a questionnaire were considered., Materials and Methods: The study teeth (FDI #36 or #46) of 81 participants (mean age 22.8 ± 2.2 years) were scanned with the intraoral scanner (IOS, Trios 3, 3Shape) at the second follow-up (T2) after an observation period of 24 months. Standard-tessellation-language datasets were superimposed with baseline (T0) and T2 scans in 3D analysis software (GOM Inspect). The maximum vertical substance loss was measured between T0 and T2 at 6/7 areas (4/5 cusps and 2 ridges) of each study tooth and data compared to the already published data of the first follow-up (T1) after 12-month observation period. The morphology of tooth wear was classified into three groups: cupping (C), facet (F) and combined cupping-facet (CF). The analysis of aetiological factors, such as acid impacts, was based on a questionnaire filled out by participants at time points T0, T1 and T2. Non-parametric tests were used for statistical analysis (p < 0.05)., Results: The buccal load-bearing cusps (mesiobuccal: median 15 μm, 95%CI 11/18 μm; mesiolingual 8 μm, 0/11 μm) were most affected by tooth wear. Loss values increased significantly at T2 compared to T1 for all areas, although significantly less than in the first 12 months (T0-T1). Areas that already exhibited F at T0 mostly displayed them also at T2 and only rarely developed further into C or CF. The only association between aetiological factors and loss values could be detected for sex as males had significantly higher loss values than females., Conclusions: Progression of tooth wear could be clearly shown with high interindividual variations in loss values among participants. This indicates the need for individual monitoring with IOS., Clinical Relevance: IOSs show the potential for patient-specific monitoring to detect the progression of tooth wear. Thus, data of 24 months fills the gap of tooth wear data for young adults in literature. Further studies over a longer observation period are highly recommended to gain more information about the dynamic of tooth wear and aetiological factors., (© 2023. The Author(s).)

Objective: The aim of this work was to study the accuracy of the intraoral scanner for detection of tooth wear in natural teeth by using micro-computed tomography (micro-CT) as a gold standard., Materials and Methods: Twenty premolars were prepared, fixed in acrylic blocks, and scanned with an intraoral scanner (iTero Element® 2) and micro-CT for baseline reference images before artificial tooth wear induction. The samples were then scrubbed with abrasive sandpaper 20 times and scanned with the intraoral scanner. They were then superimposed with the reference images utilising the "TimeLapse" feature of the scanner until the abraded area appeared yellow, indicating tooth surface loss in the 50-200 μm range. The same samples were then rescanned by micro-CT to measure the actual tooth surface loss. This procedure was repeated for the subsequent experimental tooth surface loss of 200-400 μm range (orange areas) and 400-750 μm range (red areas). The collected data were analysed for sensitivity, positive predictive value (PPV), and accuracy. Level of statistical significance was set at .05., Results: In the detection of experimental tooth surface loss, the specificity, PPV, and accuracy of the intraoral scanner were 98%, 98%, and 97%, respectively., Conclusions: The iTero® intraoral scanner can be recommended to be a suitable screening tool for tooth wear in routine dental practice., Competing Interests: Conflict of interest None disclosed., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to determine predictors of erosive tooth wear (ETW) progression, using novel primary-care quantitative analysis techniques., Methods: In a single-centre, prospective, observational cohort longitudinal study, adolescents, aged 11-18 years, underwent a baseline BEWE examination, validated risk factors questionnaire and baseline intraoral scan (IOS, TRIOS 3.0, 3Shape, Copenhagen, Denmark). One year later a repeat scan was taken. Quantitative analysis of wear progression (volume loss) on first permanent molars and upper central incisors was performed using previously published protocols. Multilevel linear regression was used to investigate the associations between baseline predictors and volume loss per mm 2 ., Results: A total of 295 dental surfaces (131 incisors and 164 molars) in 70 patients were analysed for this study. The mean age of participants at baseline was 15.0 years (SD: 0.79), and the average time between scans was 11.8 months (1.61 SD; range 10-13). The mean volume loss per mm 2 of dental surfaces was -0.013 mm 3 (SD: 0.009). Greater volume loss was observed amongst adolescents with higher baseline BEWE scores and those whose parents had lower education as well as on molar than incisor surfaces. No associations were found with dietary acid intake and intrinsic acid exposure when baseline levels of tooth wear, parental education and other factors were controlled for., Conclusions: The findings help to characterise groups at greater risk of ETW and would indicate that improved screening and upstream preventative measures should form the basis of a preventative program., Clinical Significance: Intra-orals scans and registration software might improve the ability to diagnose, monitor and prevent the early loss of dental hard tissue., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objectives: To investigate the threshold and accuracy of intraoral scanning in measuring freeform human enamel surfaces., Methods: Software softgauges, ranging between 20 and 160 µm depth, were used to compare four workflow analysis techniques to measure step height on a freeform surface; with or without reference areas and in combination with surface-subtraction to establish which combination produced the most accurate outcome. Having established the optimum combination, 1.5 mm diameter, individual depths ranging from 11 to 81 µm were created separately on 14 unpolished human enamel samples and then scanned with gold standard laboratory optical profilometry (NCLP, TaiCaan Technologies™, XYRIS2000CL, UK) and a clinical intraoral scanner (TrueDefinition™, Midmark Corp., USA). The sequence of surface registration and subtraction determined from the softgauges was used to measure step height on natural human enamel surfaces. Step heights (μm) were compared using two-way ANOVA with post-hoc Bonferroni (p < 0.05) and Bland-Altman analyses., Results: Software differences were significantly reduced from - 29.7 to - 32.5% without, to - 2.4 to - 3.6% with reference areas (p < 0.0001) and the addition of surface-subtraction after registration reduced this further to 0.0 to - 0.3% (p < 0.0001). The intraoral scanner had a depth discrimination threshold of 73 µm on unpolished natural enamel and significant differences (p < 0.05) were observed compared to NCLP below this level., Significance: The workflow of combining surface-registration and subtraction of surface profiles taken from intraoral scans of freeform unpolished enamel enabled confident measurement of step height above 73 µm. The limits of the scanner is related to data capture and these results provide opportunities for clinical measurement., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Quantitative wear measurement is of increasing interest for measuring tooth wear progression. However, most research on quantitative wear measurement has focused on simulated wear or scanned gypsum casts. A 3D Wear Analysis (3DWA) protocol has been developed that analyzes tooth wear in vivo through intra-oral scanners available to dental clinicians. This study investigated the precision of the 3DWA protocol for measuring wear through maximum height loss (mm) and volume change (mm 3 ). Observational prospective wear data from 55 patients were analyzed after 0-1-, 0-3-, and 0-5-year intervals to determine rates of wear, and convenience samples were chosen to test the protocol's precision on dentitions scanned twice in one sitting and its intra- and inter-rater precision on scans with 0-3- and 0-5-year intervals. Scans were made using intra-oral scanners (IOS) and superimposed using 3D measurement software. T-tests were performed to determine the structural and random error, and trimmed ranges were calculated to interpret the error. For protocol precision, the mean difference was 0.015 mm (-0.002; 0.032, p = 0.076) for height and -0.111 mm 3 (-0.250; 0.023, p = 0.101) for volume. The duplicate measurement error was 0.062 mm for height and 0.268 mm 3 for volume. The height measurements were precise enough to measure wear after intervals of 0-3 or 0-5 years; however, volume measurements were susceptible to procedural error and operator sensitivity. The 3DWA protocol is precise enough to adequately measure tooth height loss after intervals of a minimum of 3 years or in patients with severe wear progression, but it is not suited to measuring volumetric changes.

In recent years, there has been an increase in the incidence of dental wear; thus, an early diagnosis is important. Conventional methods of diagnosis are based primarily on the visual abilities of the dentist, and therefore the use of new technologies for the detection of dental wear may be very useful. The aim of the study was to analyze the sensitivity and specificity of the intraoral scanner for measuring dental wear, as well as to evaluate patients' satisfaction with the use of the scanner. The study was conducted with 46 volunteers who underwent three intraoral analyses: a first baseline scanning, a second scanning after 6 months and a final scanning after one year performed by four operators divided into two groups. One of the operators performed the visual analysis of dental wear, and the other performed the analysis using the intraoral scanner 3M™ True Definition intraoral scanner (ESPE, Seefeld, Germany). The data obtained from the intraoral scanner showed levels of specificity and sensitivity that enable the intraoral scanner to be used as a diagnostic tool in the assessment of tooth wear. The participants also showed a high degree of satisfaction with the scanner as a communication tool.

Purpose: To evaluate in vitro the potential of an intraoral scanner (IOS) to monitor erosive tooth wear (ETW) using different alignment software with distinct quantitative measurement metrics., Methods: 15 unpolished bovine crowns were exposed to citric acid (pH ~2.5) at 24-hour intervals up to 168 hours. At baseline and after each acid exposure episode, the teeth were scanned with IOS (3Shape TRIOS 3). Scanned images from each data point were superimposed on baseline image using WearCompare software to obtain volume loss (mm³) and area loss (mm²) and using IOS built-in software (3Shape TRIOS Patient Monitoring) to obtain depth loss (mm). Pearson's test was used to determine the correlation between acid exposure time (h) and each outcome measure (α= 0.05)., Results: As the acid exposure time increased, the lesion parameters (depth, volume, and area) increased. Friedman's test showed that relative to baseline volume loss became significant (P< 0.05) after 72 hours from median 11.48 mm³ (IQI 25% = 8.72 mm³), eroded area became significant (P< 0.05) from median 48.67 mm² (IQI 25% = 44.46 mm², P< 0.05) after 96 hours, and erosion depth became significant (P< 0.05) from median 0.69 mm (IQI 25% = 0.66 mm²) after 144 hours. A strong correlation was observed between depth (mm²) and time (r= 0.9993 P< 0.0001), volume (mm³) and time (r= 0.9968, P< 0.0001), and area (mm²) and time (r= 0.9475, P= 0.0003)., Clinical Significance: Currently, there is no quantitative method for clinical monitoring of erosive tooth wear. The present study demonstrated that the intraoral scanner is a potential clinical tool for detecting and quantitatively monitoring early and advanced erosive tooth wear., Competing Interests: The authors declared no conflict of interest. They had no known competing financial, economic, or professional interests, or personal relationships that could have appeared to influence the positions presented in this article. The São Paulo Research Foundation (FAPESP) provided financial support (processes #2019/11368-5 and #2017/24714-3)., (Copyright©American Journal of Dentistry.)

Objectives: Digital models are now frequently used in biological anthropology (bioanthropology) research. Despite several studies validating this type of research, none has examined if the assessment of dental wear magnitude based on Computerized Tomography (CT) scans is reliable. Thus, this study aims to fill this gap and assess if dental wear magnitude scoring based on CT scans provides results consistent with scoring based on direct observation of the physical specimens., Materials and Methods: Dental wear magnitude from 412 teeth of 35 mandibles originating from the Portuguese Muge and Sado Mesolithic shell-middens was scored. The mandibles were also CT scanned and visualized using 3D Slicer. CT scan-based scoring of dental wear magnitude was then undertaken. Two scoring rounds were undertaken for each observation method (totaling four scoring rounds) and an intra-observer error test was performed. The averaged results of the two observation methods were compared via boxplots with paired cases., Results: Intra-observer error was negligible and non-significant. Scoring results are comparable between the two observation methods. Notwithstanding, some differences were found, in which CT scan assessment generally overestimates dental wear when compared to direct observation., Discussion: Our results generally validate the use of CT scans in studies of dental wear magnitude. Notwithstanding several caveats relating to CT scanning and visualization limitations should be considered to avoid over or under-estimation of dental wear., (© 2021 The Authors. American Journal of Physical Anthropology published by Wiley Periodicals LLC.)

Background: The Tooth Wear Evaluation System (TWES) is a type of tooth wear index. To date, there is the lack of data comparing the reliability of the application of this index on gypsum cast records and digital greyscale intra-oral scan records., Objectives: A comparative evaluation between the use of gypsum cast records and digital greyscale intra-oral scan records with the reliability of tooth wear scoring using the TWES amongst a group of patients with tooth wear., Methods: Records for 10 patients with moderate to severe tooth wear (TWES ≥ 2) were randomly selected from a larger clinical trial. TWES grading of the occlusal/incisal, buccal and palatal/lingual surfaces was performed to determine the levels of intra- and interobserver agreement. Intra-observer reproducibility was based on the findings of one examiner only. For the interobserver reproducibility, the findings of two examiners were considered. One set of models/ records were used per patient. Cohen's weighted kappa (κ W ) was used to ascertain agreement between and within the observers. Comparison of agreement was performed using t tests (P < .05)., Results: For the scoring of the of the total occlusal/incisal surfaces, the overall levels of intra- and interobserver agreement were significantly higher using the gypsum cast records than with the digital greyscale intra-oral scan records, (P < .001) and (P < .001), respectively. For the overall buccal surfaces, only a significant difference was found in the intra-observer agreement using gypsum casts, (P = .013). For the palatal/lingual surfaces, a significant difference was only reported in the interobserver agreement using gypsum casts, (P = .043). At the occlusal/incisal surfaces, grading performed using gypsum casts, culminated in significantly higher TWES scores than with the use of the digital greyscale intra-oral scans (P < .001). At the buccal and palatal/lingual surfaces, significantly higher wear scores were obtained using digital greyscale intra-oral scan records (P < .009)., Conclusions: The TWES can offer a reliable means for the scoring of wearing occlusal/incisal surfaces using gypsum casts. The reliability offered by digital greyscale intra-oral scans for consecutive scoring was in general, inferior., (© 2021 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Objectives: The food that people and animals consume leaves microscopic traces on teeth in predictable ways, and analyses of these markings-known as dental microwear analyses-allow us to reverse engineer the characteristics of diet. However, the microwear features of modern human diets are most often interpreted through the lens of ethnographic records. Given the subtle variation within human diets when compared to other species, we need better models of how foods and processing techniques produce marks on teeth. Here, we report on the second study to target the occlusal surface microwear of living human populations, and the first to target populations other than foragers., Methods: We collected 150 dental impressions from five Kenyan communities: El Molo, Turkana (Kerio), Luhya (Webuye), Luhya (Port Victoria), and Luo (Port Victoria), representing a range of subsistence strategies and associated staple diets-fishing, pastoralism, and agriculture. Our results suggest that the occlusal microwear of these groups records differences in diet. However, biofilm obscured most of the molds obtained despite the steps taken to remove it, resulting in only 38 usable surfaces., Results: Due to the biofilm problem and final sample size, the analysis did not have enough power to demonstrate the differences observed statistically. The results and problems encountered are here explained., Conclusions: Considering that in vivo studies of dental microwear texture analysis have the potential to increase our understanding of the association between patterns of dental microwear and complex, mixed human diets, resolution of the current pitfalls of the technique is critical., (© 2020 Wiley Periodicals LLC.)

Diet affects many factors of an animal's anatomy, but teeth are a specific focus of dietary research, as their durability lends them to record information on a large variety of scales. Abrasive diets like those of grazing herbivores are known to wear down teeth, but how that wear affects tooth growth and the relations between its different morphological components is rarely investigated. Seven pelleted diets varying in abrasive size and concentration were fed over a 17-month period to 49 sheep (Ovis aries), of which n = 39 qualified for morphology measurements. Using computed tomography, scans of the skulls were made over the course of the experiment, and the impact of diet-related wear was observed on tooth volume and morphology, including the position of dental burr marks, over time. Digital caliper measurements were applied to 3D renderings of the teeth, and the volume of crown and root segments were investigated separately. We aimed to detect a signal of root growth compensating for wear, and test if this mechanism would be affected by dietary abrasives. Crown-segment volume loss was correlated to root-segment volume gain. Height and burr mark measurements indicated a much higher experimental tooth wear than that previously reported for free-ranging animals. The reason for this is unclear. There was no relationship between tooth height and dentine basin depth. For all parameters, there was no effect of diet; hence, while the measurements corroborate general understanding of tooth wear and compensatory processes, these methods appear not suitable to assess subtle differences between feeding regimes., (© 2020 American Association for Anatomy.)

Objectives: This in vitro study explored quantitative outcome measures as clinical indicators of simulated occlusal tooth wear progression., Methods: Ten sound, extracted human premolars were selected and submitted to occlusal tooth wear simulation in 0.5-mm steps (0/0.5/1.0/1.5 mm). At each step, enamel thickness on the buccal cusp tips was evaluated using cross-polarization optical coherence tomography (CP-OCT) and micro-computed tomography (μ-CT). The occlusal surface of each premolar was also scanned at each step using a 3D digital intraoral scanner, followed by morphological characterization using standard topography attributes (Slope, Relief, RFI, OPCr). Repeated measures ANOVA assessed differences in simulated wear levels for the μ-CT and CP-OCT data as well as the topography values. Correlations were also calculated between the μ-CT/CP-OCT and topography data., Results: Significant differences were observed for enamel thickness at each simulation wear stage, for both CP-OCT (p < 0.001) and μ-CT (p < 0.001), with good agreement between methods (intraclass correlation: 0.89). For topography analysis, as wear increased, the average Slope, RFI, and Relief values decreased, and average OPCr values increased, with more significant differences shown for Slope. Slope showed significant (p < 0.05) positive correlations with CP-OCT. OPCr showed significant negative correlations with μ-CT, and CP-OCT (p < 0.05). RFI and Relief were not correlated with either μ-CT or CP-OCT (p > 0.05)., Conclusions: Our findings suggest the potential of PS-OCT for measuring enamel thickness changes in the cusp tips of the occlusal surface. Similarly, conventional intraoral scanners can serve effectively for monitoring overall tooth wear when combined with dental topographic analyses of resultant point clouds., Clinical Significance: CP-OCT measures of enamel thickness and dental 3D topographic attributes showed potential as objective outcomes for the clinical monitoring of occlusal tooth wear. Their combination provided a comprehensive understanding of the tooth wear development process., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The aim of this study was to assess the utility of 3D imaging of optical coherence tomography (OCT) for the diagnosis of occlusal tooth wear ex vivo. Sixty-three extracted human molars with or without visible tooth wear were collected to take digital intraoral radiography and 3D OCT images. The degree of tooth wear was evaluated by 12 examiners and scored using 4-rank scale: 1-slight enamel wear; 2-distinct enamel wear; 3-tooth wear with slight dentin exposure; 4-tooth wear with distinct involvement of dentin. The degree of tooth wear was validated by the histological view of confocal laser scanning microscopy (CLSM). The sensitivity, specificity, and area under the curve (AUC) of receiver operating characteristic analysis were calculated. Diagnostic accuracy was compared with the agreement with CLSM observation using weighted kappa. The results were statistically analyzed at a significance level of α = 0.05. Three-dimensional OCT showed significantly higher sensitivity ( p < 0.05) for all the diagnostic thresholds of enamel wear and dentin exposure than digital radiography (0.82, 0.85, and 0.79 vs. 0.56, 0.52, and 0.57, respectively). Three-dimensional OCT showed higher AUC and kappa coefficients than digital radiography ( p < 0.05), where mean AUC and Kappa values were 0.95 and 0.76 for OCT and 0.92 and 0.47 for radiography, respectively. No significant difference of specificity was observed ( p > 0.05). Three-dimensional OCT could visualize and estimate the degree of tooth wear and detect the dentin exposure at the tooth wear surface accurately and reproducibly. Consequently, a new guideline for tooth wear assessment can be proposed using OCT.

Objectives: To assess the feasibility of detecting and monitoring early erosive tooth wear using a 3D intraoral scanner (IOS) aided by specific software., Methods: Extracted sound permanent teeth were assembled in two shortened artificial dental arches and scanned at different intervals with an IOS (3Shape TRIOS® 3) before and after an erosion/abrasion protocol (i.e. 1 h up to 24 h immersion in citric acid solution and subsequent brushing). The 3D models obtained at consecutive time points were superimposed with the baseline model using dedicated software (3Shape TRIOS® Patient Monitoring, version 2.1.1.0) and reference surface alignment. Surface profile differences between the baseline 3D model and the respective models from different time points were expressed as tooth substance loss. Non-parametric tests were used to assess the significance of tooth substance loss at different time points. Spearman's correlation was applied between the tooth substance loss at the end of each erosion/abrasion cycle and the immersion time in acid., Results: Significant tooth substance loss (0.08 mm, IQR = 0.05) was detected by the software after 3 h of erosive-abrasive challenge (p = 0.045). The overall median loss increased gradually from baseline to 24 h showing a strong correlation with the immersion time in acid (r s  = 0.971, p < 0.01)., Conclusions: The use of an IOS aided by specific software showed good performance for early detection and monitoring of tooth wear in vitro and has promising potential for in vivo application., Clinical Significance: Detection and monitoring of early erosive tooth wear can be reliably aided by intraoral scanning supported by specific software. The measurement error and uncertainty involved in this method should be taken into consideration when interpreting the tooth substance loss measurements. Furthermore, presuming the difficulty in defining reference surfaces in vivo, clinical validation is needed to determine the system's in vivo performance., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Tooth or material wear in a dentition is a common finding that requires timely diagnosis for management and prevention of further loss or associated esthetic or functional impairment. Various qualitative and quantitative methods have been suggested to measure tooth or material wear, but they present with limitations, such as imprecision, subjectivity, or high complexity. Here we developed and assessed an efficient 3D superimposition method to accurately measure occlusal tooth wear on 3D digital dental models. For this purpose, teeth on plaster casts were manually grinded on their occlusal surfaces to simulate various degrees of tooth wear. The casts were scanned using a surface scanner. Grinded tooth crowns (T1) were segmented and compared to the original crowns (T0) using five 3D surface superimposition techniques and a gold standard technique (GS). GS measurements were obtained by using intact adjacent structures as superimposition references. The technique of choice (complete crown with 30% estimated overlap of meshes) showed the best reproducibility (maximum difference < 0.050 mm 3 ) and excellent agreement with the GS technique (median difference: 0.032 mm 3 ). The suggested 3D superimposition method offers a highly efficient and accurate tool for tooth wear assessment, which could be applicable to clinical conditions.

Early modern humans (EMH) are often touted as behaviorally advanced to Neandertals, with more sophisticated technologies, expanded resource exploitation, and more complex clothing production. However, recent analyses have indicated that Neandertals were more nuanced in their behavioral adaptations, with the production of the Châtelperronian technocomplex, the processing and cooking of plant foods, and differences in behavioral adaptations according to habitat. This study adds to this debate by addressing the behavioral strategies of EMH (n = 30) within the context of non-dietary anterior tooth-use behaviors to glean possible differences between them and their Neandertal (n = 45) counterparts. High-resolution casts of permanent anterior teeth were used to collect microwear textures of fossil and comparative bioarchaeological samples using a Sensofar white-light confocal profiler with a 100x objective lens. Labial surfaces were scanned, totaling a work envelope of 204 x 276 μm for each individual. The microwear textures were examined for post-mortem damage and uploaded to SSFA software packages for surface characterization. Statistical analyses were performed to examine differences in central tendencies and distributions of anisotropy and textural fill volume variables among the EMH sample itself by habitat, location, and time interval, and between the EMH and Neandertal samples by habitat and location. Descriptive statistics for the EMH sample were compared to seven bioarchaeological samples (n = 156) that utilized different tooth-use behaviors to better elucidate specific activities that may have been performed by EMH. Results show no significant differences between the means within the EMH sample by habitat, location, or time interval. Furthermore, there are no significant differences found here between EMH and Neandertals. Comparisons to the bioarchaeological samples suggest both fossil groups participated in clamping and grasping activities. These results indicate that EMH and Neandertals were similar in their non-dietary anterior tooth-use behaviors and provide additional evidence for overlapping behavioral strategies employed by these two hominins., Competing Interests: The authors have declared that no competing interests exist.

Background: Various techniques have been suggested to quantitatively assess tooth wear; most have limited clinical application. The first aim of this in vitro study was to estimate the residual enamel thickness of teeth with various degrees of occlusal wear using quantitative light-induced fluorescence (QLF). The second aim was to identify relationships between the fluorescence parameters of QLF and the conventional tooth wear index (TWI) system., Methods: Sixty-nine extracted permanent premolars and molars with initial stages of tooth wear (TWI score 1a-2: enamel wear to dentin exposure) were used. Two blinded and trained examiners participated in evaluation procedures. Occlusal QLF-digital (QLF-D) images were acquired for selecting area of interest (AOI) and calculating fluorescence for occlusal tooth wear (ΔF wear ) of the AOI by the first examiner. Each specimen was cross-sectioned in the buccal-lingual direction. Enamel thickness from images obtained by stereomicroscopy and TWI of each sample was determined by the second examiner. Spearman correlation was used to determine the relationship of ΔF wear with enamel thickness and TWI. ΔF wear values were compared between histological scores with the Mann-Whitney U test., Results: Seventy-six AOIs were analyzed. As enamel thickness decreased, ΔF wear values significantly increased and strongly correlated with enamel thickness (Spearman rho = -0.825, P < 0.001). There were significant differences in ΔF wear values among TWI scores (P < 0.001); ΔF wear strongly correlated with TWI (Spearman rho = 0.753, P < 0.001)., Conclusions: ΔF wear values, which denote fluorescence difference by using QLF, showed a strong correlation with residual enamel thickness and tooth wear severity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background/aim: The underlying mechanism of the development of cups and grooves on occlusal tooth surfaces is still unclear. The aim of this study was to evaluate factors contributing to in vitro cup formation, in order to elucidate the clinical process., Methods: A total of 48 extracted human molar teeth were exposed to acidic aqueous solutions at pH of 4.8 and 5.5 in constant motion, in combination with different loading conditions: no load (0N group, control), 30 N (30N group) or 50 N (50N group) (n = 8 per group). Before and after 3 months of exposure (1,422,000 loading cycles), the samples were scanned using a non-contact profilometer. Pre- and post-exposure scans were subtracted and height loss and volume tissue loss were calculated. Representative samples with wear and cupping lesions were imaged using scanning electron microscopy, light microscopy and micro-computed tomography., Results: Average height and volume tissue loss at pH 5.5 was 54 µm and 3.4 mm3 (0N), 52 µm and 3.4 mm3 (30N) and 58 µm and 3.7 mm3 (50N), respectively, with no statistically significant differences. Average height and volume loss at pH 4.8 were 135 µm and 8.7 mm3 (0N), 172 µm and 12.6 mm3 (30N) and 266 µm and 17.8 mm3 (50N), respectively, with a statistically significant difference between 0N and 50N (p < 0.002). Cup-shaped lesions had formed only at pH of 4.8, in the 30N and 50N groups., Conclusion: The study showed that a cup can arise fully in enamel and that mechanical loading in addition to erosive challenges are required., (© 2019 S. Karger AG, Basel.)

Dental mesowear is applied as a proxy to determine the general diet of mammalian herbivores based on tooth-cusp shape and occlusal relief. Low, blunt cusps are considered typical of grazers and high, sharp cusps typical of browsers. However, how internal or external abrasives impact mesowear, and the time frame the wear signature takes to develop, still need to be explored. Four different pelleted diets of increasing abrasiveness (lucerne, grass, grass and rice husks, and grass, rice husks and sand) were fed to four groups of a total of 28 adult goats in a controlled feeding experiment over a 6-month period. Tooth morphology was captured by medical CT scans at the beginning and end of the experiment. These scans, as well as the crania obtained post mortem, were scored using the mesowear method. Comparisons between diet groups showed few significant differences after 6 months, irrespective of whether CT scans or the real teeth were scored. Only when assessing the difference in signal between the beginning and the end of the experiment did relevant, significant diet-specific effects emerge. Diets containing lower phytolith content caused a more pronounced change in mesowear towards sharper cusps/higher reliefs, while the feed containing sand did not result in more extreme changes in mesowear when compared with the same feed without sand. Our experiment suggests that the formation of a stable and hence reliable mesowear signal requires more time to develop than 6 months., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2018. Published by The Company of Biologists Ltd.)

Objective: Evaluate the effect of a full rehabilitation, including an increase of vertical dimension of occlusion (VDO), in patients with severe tooth wear on changes in facial appearance., Methods: Patients with severe tooth wear were restoratively treated using direct composite restorations, including an increase of the VDO. Before and one month after treatment 3D stereophotographs were taken and facial changes were measured with the use of 3D cephalometric landmarks. Cast models were used to determine the Tooth Wear Index (TWI) and the VDO-increase. The Orofacial Esthetic Scale-questionnaire was used to evaluate subjective happiness with appearance. Paired Student's t-tests were used to evaluate the changes after full rehabilitation. The relation between the facial changes, VDO-increment and TWI-score were analyzed using multiple regression models (p < 0.05)., Results: 44 Patients (35 men, 9 women, mean age: 38.2 ± 7.1 y) participated in this study. Mean TWI-score at baseline was 3.3 ± 0.5 and the mean increase in VDO was 1.6 ± 0.9 mm. Lower face height increased by 1.9 mm (p ≤ 0.001). Patients reported a significant improvement in orofacial appearance: OES-summary score of 34.3 ± 11.2 before and 59.9 ± 6.8 one month after treatment (p < 0.001). The increase of VDO resulted in an increase in Lower Face Height (p ≤ 0.002), whereas the TWI-score at baseline had no effect on the facial changes. The applied increase in VDO and TWI-score were not related to changes in OES-scores., Conclusions: A full rehabilitation with an increase in VDO resulted in objective differences in facial height as measured with 3D stereophotogrammetry., Clinical Significance: In patients with severe tooth wear, receiving a full rehabilitation including an increase in vertical dimension of occlusion, an objectively change will occur in the Lower facial height, but this effect will be subjectively judged as a positive change., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objective: To determine if the Basic erosive tooth wear index (BEWE index) is able to assess and monitor ETW changes in two consecutive cast models, and detect methodological differences when using the corresponding 3D image replicas., Methods: A total of 480 pre-treatment and 2-year post-treatment orthodontic models (n = 240 cast models and n = 240 3D image replicas) from 120 adolescents treated between 2002 and 2013 at the Gent Dental Clinic, Belgium, were scored using the BEWE index. For data analysis only posterior sextants were considered, and inter-method differences were evaluated using Wilcoxon Signed Rank test, Kappa values and Mc Nemar tests (p < 0.05). Correlations between methods were determined using Kendall tau correlation test., Results: Significant changes of ETW were detected between two consecutive models when BEWE index was used to score cast models or their 3D image replicas (p < 0.001). A strong significant correlation (τb: 0.74; p < 0.001) was shown between both methods However, 3D image-BEWE index combination showed a higher probability for detecting initial surface changes, and scored significantly higher than casts (p < 0.001). Incidence and progression of ETW using 3D images was 13.3% (n = 16) and 60.9% (n = 56) respectively, with two subjects developing BEWE = 3 in at least one tooth surface., Conclusions: BEWE index is a suitable tool for the scoring of ETW lesions in 3D images and cast. The combination of both digital 3D records and index, can be used for the monitoring of ETW in a longitudinal approach. The higher sensibility of BEWE index when scoring 3D images might improve the early diagnosis of ETW lesions., Clinical Significance: The BEWE index combined with digital 3D records of oral conditions might improve the practitioner performance with respect to early diagnosis, monitoring and managing ETW., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives: The aim of this study was to assess the clinical outcomes and patient satisfaction with monolithic zirconia crowns in patients with severe tooth wear (≥1/3 of the tooth crown) in the aesthetic zone., Methods: The historical prospective study sample consisted of 13 patients previously treated with a total of 84 monolithic zirconia crowns. The patients had been treated in a private clinic in Bergen, Norway, in the period 2012 to 2014. All patients were men, aged 35-67 years (mean age 56.3 years) and had been in need of prosthetic rehabilitation because of severe tooth wear in the aesthetic zone. Technical complications as well as biologic findings were registered when the crowns had been in function one to three years (mean 20 months). The patients completed a self-administered questionnaire regarding satisfaction with aesthetic and function., Results: No biological complications were registered in 79 of the crowns (94%), and technical complications were registered in only two patients. All patients were satisfied with the aesthetic and function of the monolithic zirconia crowns and would choose the same treatment modality if they were to be treated again., Conclusions: Within the limitations of this study, we conclude that the rate of clinical complications was low and that the patients were satisfied with the aesthetic as well as the function of the monolithic zirconia crowns., Clinical Significance: Monolithic zirconia crowns may provide a valid treatment modality in the aesthetic zone in patients with severe tooth wear., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: To evaluate the mid-term clinical performance of direct composite restorations placed in patients with pathological tooth wear needing full rehabilitation with an increase of vertical dimension of occlusion., Methods: In a prospective trial 34 patients (34.0 ± 8.4 years; 25 males, 9 females) were treated with a minimal invasive additive technique using composite restorations. The restorative treatment protocol was to provide all teeth with composite build-up restorations in an increased vertical dimension of occlusion (VDO) using the DSO-technique. Recall appointments were planned after 1 month, 1 and 3 years after treatment. Restorations were scored for clinically acceptability (FDI-criteria) and scores 4 and 5 were recorded as clinically unacceptable. Frequencies of failures and Kaplan Meier survival curves are presented and effect of relevant variables was calculated with a multifactorial Cox regression (p < 0.05)., Results: 1256 Restorations were placed, 687 anterior, 324 premolar, and 245 molar restorations. After a mean observation time of 39.7 months a total of 69 failures were observed, of which 61 restorations were repaired (score 4) and 8 were replaced (score 5). Most common reasons for failure were (chip) fractures (n = 43) and caries (n = 11). Placement of anterior restorations in two sessions led to significant 4.6 times more failures then placed in one session., Conclusions: In patients with severe tooth wear a full rehabilitation, in an increased vertical dimension of occlusion, direct composite resin restorations show a 94.8% success and 99.3% survival rate after a period of 3.5 years., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives: Dental microwear is a promising tool to reconstruct animals' diet because it reflects the interplay between the enamel surface and the food items recently consumed. This study examines the sources of inter-individual variations in dietary habits in a free-ranging population of mandrills (Mandrillus sphinx) using a combination of feeding monitoring and in vivo dental microwear textural analysis (DMTA)., Methods: We investigated the impact of seasonality and individual traits on four DMTA parameters. In parallel, we further studied the influence of the physical properties of the food items consumed on these four parameters, using three proxies (mechanical properties, estimates of phytolith and external grit contents)., Results: We found that seasonality, age, and sex all impact DMTA parameters but those results differ depending on the facet analyzed (crushing vs. shearing facets). Three DMTA parameters (anisotropy, complexity, and heterogeneity of complexity) appear sensitive to seasonal variations and anisotropy also differs between the sexes while textural fill volume tends to vary with age. Moreover, the physical properties of the food items consumed vary seasonally and also differ depending on individual sex and age., Conclusion: Considering the interplay between the tested variables and both dental microwear and diet, we reaffirm that food physical properties play a major role in microwear variations. These results suggest that DMTA parameters may provide valuable hints for paleoecological reconstruction using fragmentary fossil dental remains., (© 2017 Wiley Periodicals, Inc.)

Objective: The aim of this study is to characterize the morphological and histological features of NCCLs in a group of extracted teeth using a focus variation optical microscopic technique that is capable of detecting minute variation in surface topography., Methods: Twenty three extracted teeth containing NCCLs were collected. Histological features of the surface and longitudinal cross sections were examined using a focus variation microscope (FVM)., Results: The sample included 8 teeth with wedge-shaped lesions; the remaining 15 contained saucer-shaped lesions. Wedge-shaped lesions showed obliterated dentinal tubules, parallel furrows and micro-fractures in the surface; longitudinal cross sections revealed subsurface micro-fractures extending toward the pulp chamber. The surfaces of typical saucer-shaped lesions were smooth and relatively featureless., Conclusions: FVM imaging shows microstructures that are consistent with simultaneous erosion and toothbrush abrasion. Saucer shaped lesions have a smooth featureless surface as well as craters and dimples that could be attributed to uneven acid attack. In wedge-shaped lesions, the presence of scratches and furrows could be attributed to mechanical forces such as tooth brush abrasion. The furrows and in-surface micro-factures of wedge shaped lesions suggest a possible role of tensile stresses but require further investigation., Clinical Significance: NCCLs present in two morphologies, either saucer-shaped or wedge-shaped. Erosion and toothbrush abrasion are important in both types of lesions. Tensile stresses due to occlusal loading may be important in some wedge-shaped lesions. Knowing the etiology of cervical lesions is the key for their prevention., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objective: The purpose of this study was to assess the prevalence, distribution and intensity of tooth wear in a sample of an ancient Italian population in order to explain the pattern in terms of dietary habits and/or non-dietary tooth-use behaviors during the Early Bronze Age, with a focus on possible age-group and sex differences., Design: Well-preserved permanent teeth of individuals from the Bronze Age site of Ballabio (Lecco) in northern Italy were examined for tooth wear by different methods. Eight 3D models of teeth at increasing severity of wear were created., Results: In total, 357 permanent teeth belonging to male and female individuals were included in the study. Dental wear was present in 96.6% of the total sample. Males showed significantly greater levels of wear than females in the mandibular teeth. Both sexes exhibited a significantly different wear direction between the anterior (oblique and flat) and posterior (oblique and concave) teeth. Significant age differences were observed in the direction and level of wear in the incisors, canines and premolars, with higher wear in the older group. Complete and rotatable virtual 3D images of different wear patterns are proposed., Conclusions: The findings of the present study confirm the data from archaeological studies on this site and on northern Italian habits during the Early Bronze Age suggesting a diet rich in vegetables. The observed wear patterns can be related both to the diet of this Bronze age population, based on hard and abrasive food requiring vigorous mastication, and to sex differences in cultural practices., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objective: This longitudinal pilot study aimed to morphologically and quantitatively investigate the progress of non-carious cervical lesions (NCCLs) by using swept-source optical coherence tomography (SS-OCT)., Methods: The samples examined comprised sets of NCCL epoxy resin replicas obtained from 10 lesions in 6 patients who attended annual dental visits over 4 or 5 years. SS-OCT images of the replicas were analyzed in terms of the maximum depth (D max ) and corresponding vertical width (VW) - using an image analyzer to estimate progression of the NCCLs over time., Results: It was found that differences between wedge- and saucer-shaped lesions were morphologically distinguished well by the OCT images. There were significant differences in dimensions among D max , VW and horizontal width (HW). HW was the largest and D max was the smallest. Although no significant differences in absolute values of annual progression rates were found among D max, VW and HW, the percentage increase in D max was significantly greater compared to VW and HW. The ratios of D max to corresponding VW ranged from 0.49 to 1.01 for the wedge-shaped lesions and from 0.13 to 0.44 for saucer-shaped lesions, respectively., Conclusions: The dimensional analysis demonstrated notable progression with large variations. The wedge-shaped lesions appeared to show greater D max values compared to the saucer-shaped lesions., Clinical Significance: With respect to the depth, the wedge-shaped lesions may progress at a greater rate compared to the saucer-shaped lesions., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This report describes the diagnosis and prosthodontic management of 2 patients with a history of chronic gastroesophageal reflux disease and worn dentition. Different treatment approaches were used for oral rehabilitation. Use of conventional and contemporary restorative materials resulted in functional and esthetic prosthodontic rehabilitation with a favorable prognosis., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

This paper presents the first ever paleodontological investigation of human remains from an archeological site in Central Europe dating from the Early Bronze Age and attributed to the Strzyzow Culture. It corroborates the knowledge gained from archeological, anthropological and genetical investigations. Our study aimed to assess dental status, dental morphology and dental pathologies as well as tooth wear and enamel hypoplasia based on visual inspection and stereomicroscopic investigation. The research was supported by CBCT imaging to obtain digital images and 3D reconstructions as well as 2D radiographs essential for dental age estimation. All of the 191 teeth discovered showed morphological similarity, with adult teeth showing similar color, shape and size. A maxillary molar presenting with a unique root morphology and a mandibular molar with a rare occlusal surface were found. Both permanent and deciduous dentition presented significant tooth wear. A few specimens displayed signs of dental caries, periapical pathology and antemortem tooth loss. Three individuals exhibited linear enamel hypoplasia. CBCT provided high-quality 2D images useful for dental age estimation by non-destructive methods. Estimated dental age correlated with the age estimated by other anthropological methods. In one case, this was crucial because of insufficient material for anthropological analysis. The presented studies have proved that besides the skeleton, teeth can be used as a fundamental tool in assessing the overall health and living conditions of paleopopulations. It would seem that there is potential for considerable development to be made in the research and investigation of paleodontological material using CBCT.

This study used conventional digital radiography to estimate the rate of tooth wear (TW) of maxillary and mandibular central incisors based on a cross-sectional study design. The crown length of 1239 permanent maxillary and mandibular central incisors from 346 persons (age groups: 10, 25, 40, 55 and 70 years ± 3) were measured by three calibrated dentists. Study teeth were intact incisally, had clearly visible incisal edges and cementoenamel junctions and had natural tooth antagonists. Measures were based on digital radiographic images (N = 666) archived in MiPACS within the electronic health record (axiUm(®)) from the College of Dentistry patient database. Incisor crown length decreased at a linear rate in both arches over the 60 years represented by the age groups. The average crown length for maxillary incisors in the youngest age group was 11.94 mm, which decreased by an average of 1.01 mm by median age 70. For mandibular incisors, the average crown length in the youngest age group was 9.58 mm, which decreased by an average of 1.46 mm in the oldest age group. Males and females showed similar rates of TW. Regardless of age, females demonstrated smaller mean crown height for maxillary incisors than males (P < 0.0001). Measures by the examiners demonstrated good agreement, with an interclass correlation coefficient of 0.869 and an average intra-examiner correlation of 99.5%, based on repeated measurements (n = 100). TW was estimated to average 1.01 mm for maxillary central incisors and 1.46 mm for mandibular central incisors by age 70 years., (© 2015 John Wiley & Sons Ltd.)

Enamel thickness and dental tissue proportions have been recognized as effective taxonomic discriminators between Neanderthal and modern humans teeth. However, most of the research on this topic focused on permanent teeth, and little information is available for the deciduous dentition. Moreover, although worn teeth are more frequently found than unworn teeth, published data for worn teeth are scarce and methods for the assessment of their enamel thickness need to be developed. Here, we addressed this issue by studying the 2D average enamel thickness (AET) and 2D relative enamel thickness (RET) of Neanderthal and modern humans unworn to moderately worn upper first deciduous molars (dm(1)s) and upper second deciduous molars (dm(2)s). In particular, we used 3D μCT data to investigate the mesial section for dm(1)s and both mesial and buccal sections for dm(2)s. Our results confirmed previous findings of an Neanderthal derived condition of thin enamel, and thinner enamel in dm(1)s than dm(2)s in both Neanderthal and modern humans. We demonstrated that the Neanderthal 2D RET indices are significantly lower than those of modern humans at similar wear stages in both dm(1)s and dm(2)s (p < 0.05). The discriminant analysis showed that using 2D RET from dm(1) and dm(2) sections at different wear stages up to 93% of the individuals are correctly classified. Moreover, we showed that the dm(2) buccal sections, although non-conventionally used, might have an advantage on mesial sections since they distinguish as well as mesial sections but tend to be less worn. Therefore, the 2D analysis of enamel thickness is suggested as a means for taxonomic discrimination between modern humans and Neanderthal unworn to moderately worn upper deciduous molars., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Enamel thickness has been linked to functional aspects of masticatory biomechanics and has been demonstrated to be an evolutionary plastic trait, selectively responsive to dietary changes, wear and tooth fracture. European Late Paleolithic and Mesolithic hunter-gatherers mainly show a flat wear pattern, while oblique molar wear has been reported as characteristic of Neolithic agriculturalists. We investigate the relationships between enamel thickness distribution and molar wear pattern in two Neolithic and medieval populations. Under the assumption that dietary and/or non-dietary constraints result in directional selective pressure leading to variations in enamel thickness, we test the hypothesis that these two populations will exhibit significant differences in wear and enamel thickness patterns. Occlusal wear patterns were scored in upper permanent second molars (UM2) of 64 Neolithic and 311 medieval subadult and adult individuals. Enamel thickness was evaluated by microtomography in subsamples of 17 Neolithic and 25 medieval individuals. Eight variables describing enamel thickness were assessed. The results show that oblique molar wear is dominant in the Neolithic sample (87%), while oblique wear affects only a minority (42%) of the medieval sample. Moreover, in the Neolithic molars, where buccolingually directed oblique wear is dominant and greatest enamel lost occurs in the distolingual quadrant, thickest enamel is found where occlusal stresses are the most important-on the distolingual cusp. These results reveal a correlation between molar wear pattern and enamel thickness that has been associated to dietary changes. In particular, relatively thicker molar enamel may have evolved as a plastic response to resist wear., (Copyright © 2014 Wiley Periodicals, Inc.)

Frequently, human dentition is utilized for victim identification. This report introduces a new human identification technique based on the principle of 3-dimensional (3D) image registration of the dentition. With the aid of a dry human skull, postmortem (PM) and antemortem (AM) scenarios were assumed. The skull in its initial state composed the PM scenario. Virtual 3D PM images were reconstructed from medical CT images. The AM scenario was achieved by reconstructing the missing hard and soft tissues of the skull by dental waxes. Virtual 3D AM images were obtained by laser surface scanning. The virtual PM and AM images were registered at 2 levels: arch level and tooth level. At arch level, the deviation between the 2 images was 0.147 mm for the maxilla and 0.166 mm for the mandible. At tooth level, the deviation average ranged from 0.077 to 0.237 mm. Qualitatively, even image fit was observed for the arches, intact teeth, and teeth with minimal deficiencies. As the tooth defect increased, the alignment discrepancy increased. It is concluded that 3D image registration ensured an accurate superimposition of the 3D images and can be used as a robust tool for forensic identification.

Inferred dietary preference is a major component of paleoecologies of extinct primates. Molar occlusal shape correlates with diet in living mammals, so teeth are a potentially useful structure from which to reconstruct diet in extinct taxa. We assess the efficacy of Dirichlet normal energy (DNE) calculated for molar tooth surfaces for reflecting diet. We evaluate DNE, which uses changes in normal vectors to characterize curvature, by directly comparing this metric to metrics previously used in dietary inference. We also test whether combining methods improves diet reconstructions. The study sample consisted of 146 lower (mandibular) second molars belonging to 24 euarchontan taxa. Five shape quantification metrics were calculated on each molar: DNE, shearing quotient, shearing ratio, relief index, and orientation patch count rotated (OPCR). Statistical analyses were completed for each variable to assess effects of taxon and diet. Discriminant function analysis was used to assess ability of combinations of variables to predict diet. Values differ significantly by diets for all variables, although shearing ratios and OPCR do not distinguish statistically between insectivores and folivores or omnivores and frugivores. Combined analyses were much more effective at predicting diet than any metric alone. Alone, relief index and DNE were most effective at predicting diet. OPCR was the least effective alone but is still valuable as the only quantitative measure of surface complexity. Of all methods considered, DNE was the least methodologically sensitive, and its effectiveness suggests it will be a valuable tool for dietary reconstruction., (Copyright © 2011 Wiley-Liss, Inc.)

The aetiology of non-carious cervical lesions (NCCLs) is not well understood and still controversial. The aim of this ex-vivo study was to examine the morphological characteristics of NCCLs for clinical evidence of enamel loss above the cemento-enamel junction (CEJ) as suggested by the abfraction theory. Fifty extracted human teeth with various types of NCCLs were collected and scanned by micro computed tomography. The reconstructed three-dimensional models were evaluated from multiple aspects, including longitudinal cross-section series. The location of internal line angle and proximal exits of the lesions were evaluated in relation to the level of CEJ. The coronal margins of the lesions were inspected for evidence of enamel loss above the CEJ using the bucco-lingual longitudinal sectional images. Coronal margins of the lesions were located along and/or under the CEJ for all of the 50 samples. In most of the lesions, regardless of lesion type, the proximal exits and internal line angles were located below the CEJ. This study did not detect clinical evidence of enamel loss above the occlusal margin of NCCLs as would have been expected according to the general abfraction mechanism., (© 2010 Blackwell Publishing Ltd.)

Digital dental radiographic imaging is considered to be as diagnostically accurate as conventional film-based radiography. In addition, many digital radiographic systems offer various image enhancements that may aid in image interpretation. However, neither type of radiographic imaging technique perfectly correlates radiographic diagnoses with clinical findings. Moreover, visual digital enhancements may provide information that is diagnostically misleading. This report presents a completed patient treatment evaluation with both enhanced and unenhanced digital radiography. The outcome suggests that clinicians should be careful with the interpretation of digital radiographic images, as this can potentially result in false-positive diagnoses., (Copyright 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)