A novel method of age estimation in children using three-dimensional surface area analyses of maxillary canine apices.

The study aimed to develop a novel and reliable age estimation method using three-dimensional surface area analyses of maxillary canine apices among Malaysian children using CBCT data. A validated regression equation for age estimation was derived and correlation between chronological age and the surface areas of the developing maxillary canine's apices were investigated. Variations based on ethnicities, gender and status of root development were also investigated in terms of fit to the age estimation model. CBCT images of the patients ranging in age from 7 to 14 years were included in the study. Training sample of 191 intact permanent maxillary canines was selected from 191 CBCT images belonging to 100 Malays and 91 Chinese. Moreover, an independent validation sample of 96 permanent maxillary canines was selected from 96 CBCT images belonging to 48 Malays and 48 Chinese. Three-dimensional image modeling and surface area analyses of the developing canine's apices were performed using Mimics and 3-Matics software. A strong correlation (r = 0.978) was observed between chronological age and surface area of the developing maxillary canine's apices. 95.6% of the variation in age can be explained by surface area of canine's apices, gender and status of the root development (open/closed apices). However, ethnicity did not contributed to the fit of age estimation model. Female showed advanced development as compared to male. Mean absolute error values indicated that this newly developed 3D surface area analyses of canine apex can be used as a reliable method for age estimation among Malaysian children.

Three-dimensional image analysis of developing mandibular third molars apices for age estimation: A study using CBCT data enhanced with Mimics & 3-Matics software.

Three-dimensional imaging has improved the method of analysis in many forensic science investigations. The study aimed to derive regression equation for age estimation by investigating the relationship between chronological age and surface area of the developing mandibular 3rd molars apices. Furthermore, other predictor variables: ethnicity (Malay and Chinese), gender and status of the root development completion (open/closed apices) were also investigated in terms of fit to the age estimation model. One hundred and twenty eight training and 55 validation samples of intact mandibular 3rd molars were selected from 183 CBCT scans. The samples comprised of 93 Malays and 90 Chinese, ranging in age from 13 to 24 years. Three-dimensional image modeling and surface area analysis of the developing mandibular 3rd molars apices were performed using Mimics and 3-Matics software. Multiple linear regression analysis was used to derive age estimation model using chronological age as a dependent variable and surface area of the apices, ethnicity, gender and status of the root development completion (open/closed apices) as predictor variables. A strong inverse correlation (r = 0.95, SD = 1.144) was observed between chronological age and all the predictor variables. The results showed that 89.6% of the variation in age can be explained by the predictor variables. Mean absolute error (MAE) value of 0.8223 was observed when the derived regression equation was tested on the independent validation sample. In conclusion, three-dimensional surface area analysis of the developing mandibular 3rd molars apices can be used as a reliable method for age estimation.

Unusual Dental Morphology in a Chimpanzee: A Case Report Utilizing Cone-Beam Computed Tomography.

This case report illustrates the teeth morphology of a chimpanzee and its anatomical variations. A well-preserved skull of a male Pan troglodytes troglodyte chimpanzee was scanned using a cone-beam computed tomography machine. Measurements included tooth and crown height, root length, root canal length and width (posterior teeth), and pulp cavity length (anterior teeth). Nonmetrical parameters included number of canals and foramina per root of every root. Interestingly, the mandibular central incisor was longer than the lateral incisor, and all the mandibular anterior teeth presented with a solitary flame-shaped or conical-calcified structure in their pulp cavity. The premolars are usually dual rooted except for the first maxillary premolar that displayed 3 roots. Other unusual discoveries were the presence of bilateral radicular dens invaginatus in the mandibular first premolars and the possibility of having 2 canals and 2 foramina in the roots of the posterior teeth. The presence of conical stone mineralizations at the pulp cavity and the presence of dens invaginatus were of particular interest.

Variation in Lingual Nerve Course: A Human Cadaveric Study.

The lingual nerve is a terminal branch of the mandibular nerve. It is varied in its course and in its relationship to the mandibular alveolar crest, submandibular duct and also the related muscles in the floor of the mouth. This study aims to understand the course of the lingual nerve from the molar area until its insertion into the tongue muscle. This cadaveric research involved the study of 14 hemi-mandibles and consisted of two parts: (i) obtaining morphometrical measurements of the lingual nerve to three landmarks on the alveolar ridge, and (b) understanding non-metrical or morphological appearance of its terminal branches inserting in the ventral surface of the tongue. The mean distance between the fourteen lingual nerves and the alveolar ridge was 12.36 mm, and they were located 12.03 mm from the lower border of the mandible. These distances were varied when near the first molar (M1), second molar (M2) and third molar (M3). The lingual nerve coursed on the floor of the mouth for approximately 25.43 mm before it deviated toward the tongue anywhere between the mesial of M1 and distal of M2. Thirteen lingual nerves were found to loop around the submandibular duct for an average distance of 6.92 mm (95% CI: 5.24 to 8.60 mm). Their looping occurred anywhere between the M2 and M3. In 76.9% of the cases the loop started around the M3 region and the majority (69.2%) of these looping ended at between the first and second molars and at the lingual developmental groove of the second molar. It gave out as many as 4 branches at its terminal end at the ventral surface of the tongue, with the presence of 2 branches being the most common pattern. An awareness of the variations of the lingual nerve is important to prevent any untoward complications or nerve injury and it is hoped that these findings will be useful for planning of surgical procedures related to the alveolar crest, submandibular gland/ duct and surrounding areas.

Comparison between gutta-percha and resin-coated gutta-percha using different obturation techniques.

BACKGROUND: The aim of this study was to evaluate and compare the obturation quality between canals obturated with gutta-percha/AH Plus sealer (GP group) and resin-coated GP/EndoREZ® sealer (ER group). METHODS: A total sample of 90 mandibular premolar teeth was divided into 2 groups (2 × 45 canals): the GP group and ER group. Each group was further divided into 3 subgroups (n = 15): cold lateral compaction (CLC), warm lateral compaction (WLC) and single cone (SC). The teeth were subsequently embedded in resin and sectioned horizontally at 1, 3, 6 and 9 mm. All sections were then viewed with a stereomicroscope at ×40 magnification. The area occupied by core filling materials was determined using Cell^D software. RESULTS: With CLC, the percentage of core filling materials in the ER group was significantly higher than in the GP group at the 1- and 3-mm levels. Similarly, with WLC, the percentage of core filling material in the ER group was significantly higher than in the GP group at the 1-, 3- and 9-mm levels. With SC, the percentage of core filling materials in the ER group was significantly higher than in the GP group at all levels. CONCLUSIONS: It can be concluded that the resin-coated GP/EndoREZ® sealer is superior to the gutta-percha/AH Plus in the percentage of core filling material.

Cone beam computed tomography assessment of the maxillary incisive canal and foramen: considerations of anatomical variations when placing immediate implants.

INTRODUCTION: The maxillary incisive canal connects the roof of the oral cavity with the floor of nasal cavity and has the incisive and nasal foramina respectively at its two opposite ends. Its close proximity with the anterior incisors affects one's ability to place immediate implants in ideal position. OBJECTIVE: To avoid causing complication, variations in their dimensions were studied. MATERIAL AND METHODS: Images of ninety Mongoloids patients examined with i-CAT Cone Beam Computed Tomography were included. The sizes of the nasopalatine foramen, the incisive canal and foramen, and anterior maxillary bone thickness were measured. The direction and course of the canals were assessed. RESULTS: The mean labiopalatal and mesiodistal measurements of the incisive foramen were 2.80 mm and 3.49 mm respectively, while the labiopalatal width of the nasal foramen was 6.06 mm. The incisive canal was 16.33 mm long and 3.85 mm wide. The anterior maxillary bone has an average thickness of 7.63 mm. The dimensions of the incisive foramen and incisive canal, and anterior maxillary bone thickness demonstrated gender differences with males showing greater values. The anterior maxillary bone thickness was affected by age but this difference was not observed in canal dimensions. The majority of subjects have a funnel shape-like incisive canal with the broader opening located at its superior. They seem to have a longer slanted-curve canal with one channel at its middle portion and a narrower incisive foramen opening than those reported elsewhere. CONCLUSIONS: This study found that gender is an important factor that affected the characteristics of the IC and the amount of bone anterior to it. Male generally had bigger IC and thicker anterior bone. In addition, the anterior maxillary bone thickness was affected by aging, where it becomes thinner with increased age even though the subjects were fully dentate.

Quantification of the dental morphology of orangutans.

Orangutans are believed to have close biological affinities to humans. Teeth being the hardest tissue provide useful information on primate evolution. Furthermore, knowledge of the pulp chamber and root canal morphology is important for dental treatment. A female Bornean orangutan and a Sumatran male orangutan skull were available for this study. Both of their dentitions, comprising 50 teeth, were scanned employing the cone-beam computed tomography for both metrical and nonmetrical analyses. Measurements included tooth and crown length, root length, enamel covered crown height, root canal length (posterior teeth), length of pulpal space (anterior teeth), and root canal width. Nonmetrical parameters included number of canals per root, number of foramina in each root, and root canal morphology according to Vertucci's classification. It was found that the enamel covered crown height was the longest in the upper central incisors although the canine was the longest amongst the anterior teeth. Both the upper premolars were three-rooted while the lower second premolar of the Sumatran orangutan was two-rooted, with two foramina. The mandibular lateral incisors of the Bornean orangutan were longer than the central incisors, a feature similar to humans. In addition, secondary dentine deposition was noticed, a feature consistent with aged humans.