Enamel Thickness Measurements Research Articles

Radiographic evaluation of enamel thickness of permanent teeth: relevance and applicability.

This descriptive observational study aimed to determine clinically relevant and applicable data of enamel thickness (ETH), considering the mesio-distal differences of anterior and posterior permanent teeth and their relationships. The sample consisted of right-sided standardized radiographs of 34 individuals (21 females and 13 males), aged between 13 and 24 (average 16) years, with all permanent teeth intact and without crowding. Four periapical and four interproximal radiographs were obtained and digitized. ETH measurements (mesial to distal contact points at the dentin-enamel junction) were performed after correction for radiographic image magnification. The Students' t-test was applied to the differences between paired means, with the Pearson correlation to evaluate the correlation between them. The mesial and distal ETH increased from the anterior to the posterior teeth. Incisor ETH ranged between 0.60 and 0.84 mm. Canines, premolars, and molars were more than 1.0 mm thick, and molar enamel reached values between 1.26 and 1.44 mm. Distal ETH was significantly greater than the mesial ETH, and progressively thicker from the anterior to posterior teeth. Interproximal reduction (IPR) of the lower central and upper lateral incisors should be avoided, reduced, or performed on their distal surfaces. There is a positive and significant correlation between ETH and the mesial and distal surfaces of the teeth. Periapical radiographs and evaluation of the remaining ETH are necessary in cases of retreatment. The location and number of tooth size discrepancies should be considered in treatment planning and appropriately compensated with IPR.

Age and sex related change in tooth enamel thickness of maxillary incisors measured by cone beam computed tomography

BackgroundTo measure adequate enamel thickness of maxillary incisors in planning enamel reduction for a porcelain laminate veneer restoration in relation to chronological age and sex by using cone beam computed tomography (CBCT) in an Iraqi subpopulation.MethodsFrom 81 CBCT images, 324 maxillary incisors were examined. Enamel thickness was measured at both mesial and distal regions of the tooth in three different levels: cervical, middle, and incisal (occlusal) 1/3 at a sagittal section. Measurements were made for the following tooth areas using CBCT: facial enamel thickness at 1, 3, and 5 mm from the cementoenamel junction (CEJ), palatal enamel thickness at 5 mm from the CEJ (5 mm P), facial and palatal enamel thickness at the incisal edge (IFP), mid incisal enamel thickness (IET), and the incisal edge enamel-pulp distance (IEPD). Relationships of enamel thickness with age and sex were evaluated using Independent t-test, Mann–Whitney U-test and the Pearson correlation coefficient, a simple linear regression analysis used for statistical analysis.ResultsSignificant differences (P < 0.05) were found in terms of an inverse association between enamel thickness and chronological age at all measurements above the CEJ and the regression model for the mid-incisal enamel thickness was (R2 of 0.4). In contrast, there was an increase in IFP, palatal, and IPED enamel thickness with age. Also, significant differences were found in enamel thickness between males and females, the enamel being thicker in females in relation to facial enamel thickness, enamel palatal thickness above CEJ and IET, while for IEPD, the enamel thickness was greater in males compared to females.ConclusionThe measurements for enamel thickness outcome variables in relation to chronological age revealed significant differences for each measured distance and there were statistically significant differences in enamel thickness between males and females at all measurements except at IFP. These results demonstrate that CBCT can be used for noninvasive, accurate measurements of enamel thickness in both sex.

Measuring Dental Enamel Thickness: Morphological and Functional Relevance of Topographic Mapping.

The interest in the development of dental enamel thickness measurement techniques is connected to the importance of metric data in taxonomic assessments and evolutionary research as well as in other directions of dental studies. At the same time, advances in non-destructive imaging techniques and the application of scanning methods, such as micro-focus-computed X-ray tomography, has enabled researchers to study the internal morpho-histological layers of teeth with a greater degree of accuracy and detail. These tendencies have contributed to changes in established views in different areas of dental research, ranging from the interpretation of morphology to metric assessments. In fact, a significant amount of data have been obtained using traditional metric techniques, which now should be critically reassessed using current technologies and methodologies. Hence, we propose new approaches for measuring dental enamel thickness using palaeontological material from the territories of northern Vietnam by means of automated and manually operated techniques. We also discuss method improvements, taking into account their relevance for dental morphology and occlusion. As we have shown, our approaches demonstrate the potential to form closer links between the metric data and dental morphology and provide the possibility for objective and replicable studies on dental enamel thickness through the application of automated techniques. These features are likely to be effective in more profound taxonomic research and for the development of metric and analytical systems. Our technique provides scope for its targeted application in clinical methods, which could help to reveal functional changes in the masticatory system. However, this will likely require improvements in clinically applicable imaging techniques.

Evaluation of sexual dimorphism in human premolars using longitudinal ground sections- A cross sectional study

Introduction: Sex determination plays an important role in forensics. On average, males possess larger tooth crowns than females in contemporary human populations, although the degree of dimorphism varies within different populations. Ground sectioning of teeth can provide an accurate measurement of enamel and dentinal thickness and can be used for gender determination in forensic analysis.&#x0D; Aim: The main aim of this study is to evaluate sexual dimorphism in human premolars using longitudinal ground sections.&#x0D; Materials &amp; Method: In this study extracted premolar teeth of males and females were taken. Longitudinal ground sectioning of these teeth was made and later examined under light microscope under customized grids.&#x0D; Results: Data was statistically analyzed and results were tabulated. It was found that enamel area and average enamel thickness was higher in females than males and coronal dentinal areas were more in males.&#x0D; Conclusion: Results of this study suggest that the differences in crown morphology among males and females can be used as a potential tool in forensic analysis.

Predictability of Proximal Enamel Thickness Assessment using Intraoral Periapical Radiographs: A Cross-sectional Study

Introduction: Measurements of tooth crown dimensions and enamel thickness are useful guides for interproximal stripping procedures aimed at creating space. In borderline non extraction orthodontic treatment cases, interproximal stripping is performed to gain space. Intraoral periapical radiographs and bitewing radiographs are commonly used to determine Proximal Enamel Thickness (PET). Aim: To determine the predictability of using IOPA-based PET measurements for assessing real/anatomic PET. Materials and Methods: This was a single-centre, crosssectional study conducted at Saveetha Dental College and Hospital, Chennai, Tamil Nadu, India, between March 2022 and April 2022. Digital Intraoral Periapical Radiographs (IOPAs) of 40 premolar teeth with intact crown structures were obtained using the paralleling technique. The PET of both the mesial and distal sides of the same teeth was measured using Carestream Imaging software. Subsequently, the extracted teeth were sectioned and examined under a Stereomicroscope (SM), and PET measurements of the mesial and distal surfaces were obtained along the heights of contour using ImageJ analysis software. Pearson’s correlation, along with linear and polynomial regression analyses, was performed using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) software. Results: A low but significant positive correlation between the PET of the sectioned teeth and the PET measured from IOPAs was observed (p=0.002, R=0.55). A significant difference in PET between the two methods for both sides was noted (p&lt;0.05). The mean distal enamel thickness was significantly greater than the mean mesial enamel thickness for both the IOPA and SM methods (p&lt;0.05). A polynomial regression equation, Y=2.084- 1.234X+0.318X3 , was established to predict PET of the sectioned teeth (Y) based on PET measured from IOPAs (X). Conclusion: The present study establishes a correlation between the true PET of teeth measured using cut-sections and PET measured from IOPAs, which are readily available in clinical practice. A correlation coefficient was determined, and PET can be predicted using IOPAs, although not with absolute accuracy. Distal PET was found to be higher than mesial PET, with no significant difference in enamel thickness between the two sides.

Assessment of the Accuracy in Measuring the Enamel Thickness of Maxillary Incisors with Optical Coherence Tomography

Although the clinical assessment of enamel thickness is important, hardly any tools exist for accurate measurements. The purpose of this study was to verify the precision of enamel thickness measurements using swept-source optical coherence tomography (SS-OCT). Human extracted maxillary central and lateral incisors were used as specimens. Twenty-eight sites were measured in each specimen. The optical path length (OPL) at each measurement site was measured on the OCT images, and enamel thickness (e1) was calculated by dividing OPL by the mean refractive index of enamel, 1.63. The specimens were then sectioned, and a light microscope was used to measure enamel thickness (e2). e1 and e2 were then compared. Measurement errors between e1 and e2 for the central and lateral incisors were 0.04 (0.02; 0.06) mm and 0.04 (0.02; 0.07) mm [median value: (25%, 75% percentile)], respectively. No significant differences between measurement sites were noted for measurement errors between e1 and e2. These results demonstrate that OCT can be used for noninvasive, accurate measurements of enamel thickness.

ENAMEL THICKNESS MEASUREMENTS ON 3D RECONSTRUCTIONS OF TEETH FOR PALEONTOLOGICAL APPLICATIONS

Abstract. Findings of teeth play a significant role in palaeoanthropology. And excavations in Vietnamese LangTrank cave serve as a vivid example and evidence of this statement. Teeth constitute the majority of the paleontological material dated to Middle and Late Pleistocene periods. This is to some extent the result of dietary preferences of porcupines as these rodents include in their diets bones of animals however avoiding extremely hard coronal parts of teeth. Under such circumstances teeth serve a key to taxonomic differentiation of findings as genetic analysis is often hindered by a lack of preserved DNA at such dating of material. However morphological analysis is difficult in some cases either, as teeth can be worn out or broken. In that case enamel thickness measurements become an effective study instrument as this feature varies between species. In the current study two teeth with clear signs of expressed dental wear, presumably upper fourth premolars of wild boar required more detailed analysis. Thus they were reconstructed after micro-computed tomography scanning similarly to other upper teeth picked for comparison: orang-utan tooth from the same location and two teeth from the Upper Palaeolithic Sunghir (they have been scanned earlier). This study required new approaches to image processing and measurement methodology due to marked attrition of the samples. The workflow and results of enamel thickness assessments which facilitated taxonomical differentiation of the findings are presented in the article.

Odontometric analysis using CBCT for sexual dimorphism in Egyptian-Fayoum population in case of normal occlusion

Objectives of this study was to evaluate odontometric linear measurements obtained from CBCT software including mesiodistal, tooth length dimensions and enamel thickness of the mandibular canine and mandibular first molar and arch measurements for sexual dimorphism in Egyptian population sample. Material and Methods: The study was carried out on 100 patients who visited the department of oral and maxillofacial radiology, Fayoum University for dental treatments. The study sample were grouped into two groups, group A (50 males) and group B (50 females) aged between 18-25 years old. The teeth which were selected for linear measurements using CBCT in the present study were 100 mandibular permanent canines (Lower 3) and 100 mandibular permanent 1st molar (Lower 6), for each group respectively. The linear measurements were taken on crown width and height, Enamel thickness, arch depth and width. Results: There was a highly significant difference between Male and Female for odontometric measurements of mandibular right and left canines and 1st molars including (CWL3, CLL3, CWL6 and CLL6) while enamel thickness measurements showed non-significant differences between males and females including (ETL3 at cusp tip, ETML6, ETDL6 and ETL6 at mesio-lingual cusp tip). Arch measurements including (ICW, IMW through fossa and IMW through contact) showed high significant differences between males and females. Conclusion: Odontometric parameters including mandibular canine, mandibular first molar crown width and length, inter-canine width and inter-molar width measurements based on CBCT imaging show highly significant gender difference. Thus, the parameters can be simple and reliable sexual dimorphism for medicolegal purpose.

In vivo effect of fluoride combined with amoxicillin on enamel development in rats.

Some evidence in vitro suggested that amoxicillin and fluoride could disturb the enamel mineralization. Objective: To assess the effect of amoxicillin and of the combination of amoxicillin and fluoride on enamel mineralization in rats. Methodology: In total, 40 rats were randomly assigned to four groups: control group (CG); amoxicillin group (AG - amoxicillin (500 mg/kg/day), fluoride group (FG - fluoridated water (100 ppm -221 mg F/L), and amoxicillin + fluoride group (AFG). After 60 days, the samples were collected from plasma and tibiae and analyzed for fluoride (F) concentration. The incisors were also collected to determine the severity of fluorosis using the Dental Fluorosis by Image Analysis (DFIA) software, concentration of F, measurements of enamel thickness, and hardness. The data were analyzed by ANOVA, Tukey’s post-hoc test, or Games-Howell post-hoc test (α=0.05). Results: Enamel thickness of the incisors did not differ statistically among the groups (p=0.228). Groups exposed to fluoride (AFG and FG) have higher F concentrations in plasma, bone and teeth than those not exposed to fluoride (CG and AG). The groups showed a similar behavior in the DFIA and hardness test, with the FG and AFG groups showing more severe fluorosis defects and significant lower hardness when compared with the AG and CG groups, with no difference from each other. Conclusion: The rats exposed to fluoride or fluoride + amoxicillin developed dental fluorosis, while exposure to amoxicillin alone did not lead to enamel defects.

A robust alternative to assessing three-dimensional relative enamel thickness for the use in taxonomic assessment.

Three-dimensional relative enamel thickness (3DRET) is important for assessing hypotheses about taxonomy, phylogeny, and dietary reconstruction for primates. However, its weaknesses have not been thoroughly investigated. Here, we analyze its weaknesses and propose an index aiming at better taxonomic discrimination. The dimensionless 3D index, ratio of enamel-thickness to dentine-thickness (3DRED), which is defined as the cubic root of the ratio of 3D average enamel thickness (3DAET) to 3D average dentine thickness (3DADT), is proposed here. To compare 3DRET and 3DRED and their sensitivity to voxel size, a fossil orangutan molar was scanned 14 times with different resolutions ranging from 10 to 50 μm. Enamel thickness analysis was carried out for each resultant digital model. In addition, enamel thickness measurements of 179 mandibular permanent molars (eight genera) were analyzed, followed by investigating the relationship between 3DRET and 3DAET and between 3DRED and 3DAET. Regarding sensitivity, 3DRED is more robust than 3DRET. In addition, 3DRET is correlated with 3DAET by linear curve with regression coefficients approximating or larger than 0.8 in most cases, while 3DRED shows less correlation with 3DAET. Furthermore, there are clear separations between different taxa in the bivariate plot of 3DRED against 3DAET, indicative of the taxonomic value of 3DRED. Under certain conditions, 3DRED promises to be a robust and reliable alternative to 3DRET in taxonomic study.

Enamel thickness and growth rates in modern human permanent first molars over a 2000 year period in Britain.

This study explores variation and trends in first molar enamel thickness and daily enamel secretion rates over a 2000 year period in Britain. Permanent first molars (n = 89) from the Roman, Anglo-Saxon, and Medieval periods, as well as modern-day Britain, were analyzed using standard histological methods. Relative enamel thickness (RET) and linear measurements of cuspal and lateral thickness were calculated for mesial cusps. Daily secretion rates (DSRs) were calculated for inner, mid, and outer enamel regions in both cuspal and lateral enamel. Significant differences and trends were identified between samples using nonparametric statistical tests. Enamel thickness differed between some populations, but no temporal trends were identified. Early Anglo-Saxon molars had significantly thinner RET than both Late Anglo-Saxon (p < .00) and Medieval (p < .00) molars. Lateral enamel from the Roman molars was significantly thinner than the modern-day sample (p = .04). In contrast, a significant slowing trend in DSRs was observed across the more ancient to modern-day samples in every measured region except the mid-lateral enamel region. This study presents the first evidence for a gradual slowing in the daily rate that enamel is secreted in molars over the past 2000 years in Britain. However, this trend was not matched by consistent or significant positive or negative shifts in enamel thickness. These findings suggest that modern human molars of similar enamel thickness, from different modern and ancient populations, formed at different rates.

In vitro longitudinal evaluation of enamel wear by cross-polarization optical coherence tomography

ObjectivesEnamel thickness determination by Cross-Polarization Optical Coherence Tomography (CP-OCT) is a promising approach for quantitative monitoring of tooth wear progression. This study evaluated the ability of CP-OCT to quantify the thickness of natural enamel before, during and after tooth wear simulation. Materials and MethodsNatural, unpolished human dental enamel slabs were submitted to five wear stages (Wear 1: to level the surfaces; Wear 2 to Wear 5: 0.05±0.02mm reduction each) simulated by an automatic grinding/polishing machine. Enamel thickness was evaluated with CP-OCT and a gold-standard method (micro-CT) at baseline and after every wear stage. Data were analyzed using ANOVA with pairwise comparisons for wear stages’ impact on the thickness and wear depth measurements. The inter-method agreement was analyzed using intra-class correlation coefficients, the difference between means, and Bland-Altman plots. ResultsEnamel thickness measurements (mean±standard error, in mm) with natural (1.40±0.05) and worn surfaces (1.08±0.02) by CP-OCT did not differ significantly from those measured by micro-CT (natural=1.39±0.05; worn=1.09±0.02; p-values=0.30 and 0.39, respectively). CP-OCT and micro-CT showed excellent agreement on natural (ICC=0.98) and worn surfaces (ICC=0.98) enamel thickness measurements. Among and between wear stages, there were significant differences in enamel thickness and wear depth measurements for both methods (p-value <0.0001 for all). Both methods yielded similar measurements’ mean (0.14±0.01; p-value=0.87) and were in good agreement (ICC=0.77) for wear depth estimation. SignificanceCP-OCT allows accurate measurement of enamel thickness on natural tooth surfaces. Enamel thickness measurement by CP-OCT allows quantitative monitoring of enamel thickness changes and wear depth following progressive wear.

Accuracy and reliability of enamel and dentin thickness measurements on micro-computed tomography and digital periapical radiographs#

Abstract In the application of scientific human skeletal variation in medico-legal matters, virtual anthropology is the current technique performed to examine skeleton and its body parts. Digital imaging techniques are used in many areas of dentistry and forensic dentistry. Among all digital imaging modalities, digital periapical radiography (PR) are the most widely used, however, new contemporary imaging techniques micro-computed tomography (Micro-CT) can be also used. The aim of this study was to assess the accuracy and reliability of enamel and dentin thickness measurement through intra and inter-observer error analysis, and comparison was made between periapical radiographs and Micro-CT methods. In this study 15 maxillary first premolar were used which extracted for various reasons. Enamel and dentin thicknesses and maximum cervical crown widths (MCCW) of 15 premolar teeth were examined in both Micro-CT and periapical radiographs. The results obtained with the exact maximum cervical crown widths were compared Image J software version. A digital caliper was used to measure the actual MCCW of the teeth. Results exhibited no significant differences in the measurements by the intra or inter-observer error analyses. The intraclass correlation coefficients (ICC) were more than 0.95 by both intra and inter-observer error analyses. There was significant differences in the measurements by PR and Micro-CT methods. By parameters, Micro-CT showed the highest R value (0.962) with the least error in different methods and observers. In conclusion, dentin and enamel measurements by Micro-CT was highly accurate and reliable as in the conventional method (PR). Micro-CT evaluations should be recommended for implementation in the future anthropological studies especially in countries with limited source of dental data.

Neandertal features of the deciduous and permanent teeth from Portel-Ouest Cave (Ariège, France).

We describe 14 unpublished and nine published teeth from the Mousterian level of Portel-Ouest (Ariège, France), dated to 44 ka. In a comparative context, we explore the taxonomical affinities of those teeth with Neandertals and modern humans which are both known to exist at that time. We further make some paleobiological inferences about this human group. The comparative analysis of Neandertals and modern humans is based on nonmetric traits at the outer enamel surface and the enamel-dentine junction, crown diameters and three-dimensional (3D) enamel thickness measurements of lower permanent teeth. The crown and roots are explored in detail based on the μCT-scan data to identify the multiple criteria involved in the paleobiological approach. Nonmetric traits and 3D enamel thickness tend to be more similar to Neandertals than modern humans, notably for C1 , P4 , and M2 (included in all analyses) as well as volume of the pulp cavity in roots of the anterior permanent teeth. The Portel-Ouest sample corresponds to a minimum of seven juveniles, one or two adolescents and one adult, which exhibit recurrent linear enamel hypoplasia (up to five events for one individual), the torsiversion of one anterior tooth and irregular oblique wear in some anterior deciduous teeth. This morphological study confirms that the remains from Portel-Ouest are Neandertals, associated with a Mousterian complex. Furthermore, we found the expected pattern of mortality and stress for a Neandertal group, that is, various age categories and developmental defects (nonexclusive to Neandertals), while adults are underrepresented and juveniles are overrepresented. Further excavations would contribute finding new remains and maybe complete this demographic profile.

Neutron scanning reveals unexpected complexity in the enamel thickness of an herbivorous Jurassic reptile.

Eilenodontines are one of the oldest radiation of herbivorous lepidosaurs (snakes, lizards and tuatara) characterized by batteries of wide teeth with thick enamel that bear mammal-like wear facets. Unlike most reptiles, eilenodontines have limited tooth replacement, making dental longevity particularly important to them. We use both X-ray and neutron computed tomography to examine a fossil tooth from the eilenodontine Eilenodon (Late Jurassic, USA). Of the two approaches, neutron tomography was more successful and facilitated measurements of enamel thickness and distribution. We find the enamel thickness to be regionally variable, thin near the cusp tip (0.10 mm) but thicker around the base (0.15–0.30 mm) and notably greater than that of other rhynchocephalians such as the extant Sphenodon (0.08–0.14 mm). The thick enamel in Eilenodon would permit greater loading, extend tooth lifespan and facilitate the establishment of wear facets that have sharp edges for orally processing plant material such as horsetails (Equisetum). The shape of the enamel dentine junction indicates that tooth development in Eilenodon and Sphenodon involved similar folding of the epithelium but different ameloblast activity.

Sexual dimorphism of enamel area, coronal dentin area, bicervical diameter and dentinoenamel junction scallop area in longitudinal ground section.

Introduction:Sex determination plays an important role in forensics; several studies done using radiographs, model cast and animal teeth have shown that males possess larger tooth crown and more dentin than that of the females. As physical sectioning of tooth provides more accurate measurement of enamel thickness when compared with other methods, the present study was done to evaluate and compare enamel area (EA), coronal dentin area (CDA), bi-cervical diameter (BCD), average enamel thickness (AET) and dentinoenamel junction scallop area (DEJ-SA) in longitudinal ground sections of first premolars between males and females.Materials and Methods:A total of 60 extracted first premolar teeth were used for the study, of which 30 were from male and 30 were from female. A longitudinal ground section of 15 maxillary and 15 mandibular premolars of approximately 50 μm was prepared buccolingually at the center of each tooth and mounted on the slide. Multiple photomicrographs were captured with the help of Image Analysis System Software-Progres, Speed XT core 3. EA, CDA, length of the dentinoenamel junction and BCD were measured. Average DEJ-SA and AET were also calculated.Results:Mann–Whitney U- test was used for statistical analysis. It was found that EA and AET were significantly greater in females than in males. On the contrary, it was found that CDA was significantly greater in males than in females. However, no significant difference was found in BCD and DEJ-SA between males and females.Conclusion:Permanent first premolar can be reliably used in the field of forensic in establishing gender of individuals by measuring its EA, CDA and AET.

Enamel Thickness Determination by Optical Coherence Tomography: In vitro Validation

Optical coherence tomography (OCT) has been introduced in dentistry as a nondestructive diagnostic imaging tool that does not utilize ionizing radiation. This study investigated the agreement between polarization-sensitive OCT (PS-OCT), microcomputed tomography (μ-CT), and histology for enamel thickness measurements. Human enamel samples were prepared and evaluated with μ-CT and PS-OCT and then sectioned and observed via digital transversal light microscopy. For all methods, a standard transversal section (b-scan) in each sample was selected, and the enamel thickness was measured at three predetermined positions using ImageJ analysis software. The results revealed significant high agreement between all tested methods, indicating the potential of PS-OCT as a clinical tool to effectively measure enamel thickness.

High-Resolution Ultrasonic Imaging of Dento-Periodontal Tissues Using a Multi-Element Phased Array System.

Intraoral ultrasonography uses high-frequency mechanical waves to study dento-periodontium. Besides the advantages of portability and cost-effectiveness, ultrasound technique has no ionizing radiation. Previous studies employed a single transducer or an array of transducer elements, and focused on enamel thickness and distance measurement. This study used a phased array system with a 128-element array transducer to image dento-periodontal tissues. We studied two porcine lower incisors from a 6-month-old piglet using 20-MHz ultrasound. The high-resolution ultrasonographs clearly showed the cross-sectional morphological images of the hard and soft tissues. The investigation used an integration of waveform analysis, travel-time calculation, and wavefield simulation to reveal the nature of the ultrasound data, which makes the study novel. With the assistance of time-distance radio-frequency records, we robustly justified the enamel-dentin interface, dentin-pulp interface, and the cemento-enamel junction. The alveolar crest level, the location of cemento-enamel junction, and the thickness of alveolar crest were measured from the images and compared favorably with those from the cone beam computed tomography with less than 10% difference. This preliminary and fundamental study has reinforced the conclusions from previous studies, that ultrasonography has great potential to become a non-invasive diagnostic imaging tool for quantitative assessment of periodontal structures and better delivery of oral care.

Radiographic technique and brackets affect measurements of proximal enamel thickness on mandibular incisors.

To investigate the influence of radiographic film and tube positioning, the presence and the size of brackets on in vitro measurements of proximal enamel thickness of mandibular incisors on periapical radiographs aimed to aid planning of interproximal enamel reduction procedures in orthodontics. Eighty human mandibular incisors were assigned to sets of four and located in a customized base. Periapical radiographs were taken with the film positioned at three different angles (0°, 2°, and 5°) in relation to the frontal plane and the tube head positioned at five angles (0°, -2°, -5°, +2°, and +5°) in relation to the sagittal plane. The proximal enamel width was calculated by means of computerized image analysis and compared with measurements obtained at 0°. Statistical analysis was carried out to compare the enamel measurements on radiographs made with all angular combinations with and without the presence of brackets of different dimensions. A significant difference (P < 0.05) was found between the measurements of proximal enamel width obtained at the different angles in relation to the frontal and sagittal planes for all sets with or without brackets. The presence of brackets significantly affected the measured width only for the enamel side further away from the radiation source at the sagittal plane (P < 0.05). Angular changes in taking periapical radiographs of mandibular incisors and the presence of brackets significantly affect interproximal enamel measurements made with image analysis software.

In Vitro Enamel Thickness Measurements with Ultrasound

In the work described here, agreement between ultrasound and histologic measurements of enamel thickness in vitro was investigated. Fifteen extracted human premolars were sectioned coronally to produce 30 sections. The enamel thickness of each specimen was measured with a 15-MHz hand-held ultrasound probe and verified with histology. The speed of sound in enamel was established. Bland–Altman analysis, intra-class correlation coefficient and Wilcoxon sign rank test were used to assess agreement. The mean speed of sound in enamel was 6191 ± 199 m s−1. Bland–Altman limits of agreement were −0.16 to 0.18 mm when the speed of sound for each specimen was used, and −0.17 to 0.21 mm when the mean speed of sound was used. Intra-class correlation coefficient agreement was 0.97, and the Wilcoxon sign rank test yielded a p-value of 0.55. Using the speed of sound for each specimen results in more accurate measurement of enamel thickness. Ultrasound measurements were in good agreement with histology, which highlights its potential for monitoring the progressive loss of enamel thickness in erosive tooth surface loss.