Evaluation of mandibular indices and cephalometric parameters in adolescents with impacted maxillary canines

Objectives: Maxillary impacted canines have an important place in orthodontics for the reason of being a common anomaly and its treatment is time consuming and difficult. The aim of this study was to investigate the mandibular indexes and cephalometric parameters in adolescents with impacted maxillary canines. Materials and Methods: The radiographs of 4026 patients aged 12–19 years old were scanned and a total of 155 patients were included in the study. Subjects were divided into three groups according to the permanent maxillary canines: Bilateral impacted canine (BIC) (52 subjects; mean age 15.02 ± 1.74 years), unilaterally impacted canine (UIC) (51 subjects; mean age 14.89 ± 1.39 years), and the control (52 subjects; mean age 14.84 ± 1.65 years) groups. Skeletal, soft tissue and dental measurements were performed on cephalometric radiographs. Mandibular index analyzes including the panoramic mandibular index (PMI), mental index (MI), antegonial index (AI), and gonial index (GI) measurements and also angular measurements of impacted maxillary canines were performed on panoramic radiographs. Data were analyzed statistically and P < 0.05 was considered significant. Results: Maxillary skeletal and dental measurements showed retrusive positioned maxillary dental arch in the sagittal direction in the impacted canine groups (P < 0.05). PMI and MI values were greater in the BIC and UIC groups than in control group (P < 0.05). There was no statistically significant difference in AI value among groups (P < 0.05). GI value of BIC group was found statistically lower than other groups (P < 0.05). Conclusion: Individuals with impacted maxillary canines have more retrusive maxillary dental arch and soft-tissue components. Furthermore, mandibular cortex was thicker in subjects with impacted maxillary canine than individuals with not and clinicians should keep in mind this when examine the panoramic radiographs in terms of early diagnosis of impacted maxillary canine teeth.

Dental Macrowear Reveals Ecological Diversity of Gorilla Spp.

Size and shape variation of molar crowns in primates plays an important role in understanding how species adapted to their environment. Gorillas are commonly considered to be folivorous primates because they possess sharp cusped molars which are adapted to process fibrous leafy foods. However, the proportion of fruit in their diet can vary significantly depending on their habitats. While tooth morphology can tell us what a tooth is capable of processing, tooth wear can help us to understand how teeth have been used during mastication. The objective of this study is to explore if differences in diet at the subspecies level can be detected by the analysis of molar macrowear. We analysed a large sample of second lower molars of Grauer’s, mountain and western lowland gorilla by combining the Occlusal Fingerprint Analysis method with other dental measurements. We found that Grauer’s and western lowland gorillas are characterised by a macrowear pattern indicating a larger intake of fruit in their diet, while mountain gorilla’s macrowear is associated with the consumption of more folivorous foods. We also found that the consumption of herbaceous foods is generally associated with an increase in dentine and enamel wear, confirming the results of previous studies.

ORIENTATION VS. ORIENTATION: IMAGE PROCESSING FOR STUDIES OF DENTAL MORPHOLOGY

Many odontological studies held through application of traditional and modern techniques, especially when related to measurements and morphology, very much depend on methodological aspects referred to orientation of teeth. And this is particularly relevant to new imaging and 3d reconstruction implemented in dental research and practice in a wide range of disciplines from anthropology to dentistry. The current paper deals with studies of palaeoanthropological findings dating back to the Upper Palaeolithic period in Central Russia – well-known archaeological site of Sunghir. Micro-computed tomography has been used for digital reconstructions of teeth – molars and premolars representing well-preserved dental morphology of an adolescent individual. This is due to new opportunities introduced by 3d reconstruction techniques in general and high-resolution x-ray imaging in particular that this study has become relevant. Thus digital techniques do not only provide for operating convenience but, which is even more important, allow application of image processing algorithms. In the suggested methodology these are automated, based on morphological interpretations and serve for orientation of studied teeth for further measurements. At the same time micro-computed tomographic imaging allows accurate reconstruction of other morphologically important structures which are used for an alternative orientation algorithm. Comparisons of dental measurements’ results obtained through automated digital odontometry (aDo) after both orientations applied are presented in the current paper.

The canine counts! Significance of a craniodental measure to describe sexual dimorphism in canids: Golden jackals (Canis aureus) and African wolves (Canis lupaster)

Sexual dimorphism is a widespread phenomenon among mammals, including carnivorans. While sexual dimorphism in golden jackals (Canis aureus) has been analysed in the past, in the related and apparently convergent canid, the African wolf (Canis lupaster), it is poorly studied and showed to be relatively small. Previously, sexual size dimorphism (SSD) research in these species was mostly based on skull and body measurements. In our study, we also included dental measurements, namely the diameter of the canine. We used 11 measured sections of 104 adult specimens, comprising 61 golden jackal and 43 African wolf skulls. Data analyses were carried out through logistic regression and conditional inference trees (CIT). To compare the results of SSD to other species, sexual dimorphism indices (SDI) were calculated. Golden jackals and African wolves show significant sexual size dimorphism, both in cranial and dental size. The logistic regression revealed that the mesiodistal diameter of the upper canine is most effective in discerning the sexes. The difference in the calculated SDI of the canine diameter between the sexes amounted to 8.71 in golden jackals and 14.11 in African wolves, respectively—with regional diversity. Thus, the canine diameter is an important measure to investigate SSD as well as an easy tool to apply in the field.

Comparison of Dentoalveolar Bony Defects Measurements by Dental Radiography and Computed Tomography in Companion Animals

Background: Dental disorders are commonly encountered in companion animals and diagnosed with dental radiography (DTR) and computed tomography (CT). No study has been reported previously that compares dental measurements from DTR and CT in companion animals with periodontitis-related bone loss. The purpose was to compare the DTR and CT of bony defects in cats and dogs with dental disease.Methods: This is a retrospective study and the records of Jeonbuk Animal Medical Center were reviewed between June 2019 and October 2020. All patients underwent both modalities. In DTR, bisecting angle technique was used. In CT, slice thickness was applied at either 0.5 mm or 1.0 mm depending on the size of the patients. Bony defects of dentoalveolar structures were measured.Result: Eight dogs and eight cats with dental disease were included. All measurements in both cats and dogs were smaller in DTR than in CT. Additionally, CT with thin slice thickness provided more sufficient and accurate information for dental diagnosis. Conclusively, CT examination for dental disease showed to be superior in the assessment of periodontitis-related bone lesions by obtaining precise images without distortion and overlap and can possibly substitute DTR in cats and small dogs.

Comparison of cephalometric measurements between conventional and automatic cephalometric analysis using convolutional neural network

Objective The rapid development of artificial intelligence technologies for medical imaging has recently enabled automatic identification of anatomical landmarks on radiographs. The purpose of this study was to compare the results of an automatic cephalometric analysis using convolutional neural network with those obtained by a conventional cephalometric approach. Material and methods Cephalometric measurements of lateral cephalograms from 35 patients were obtained using an automatic program and a conventional program. Fifteen skeletal cephalometric measurements, nine dental cephalometric measurements, and two soft tissue cephalometric measurements obtained by the two methods were compared using paired t test and Bland-Altman plots. Results A comparison between the measurements from the automatic and conventional cephalometric analyses in terms of the paired t test confirmed that the saddle angle, linear measurements of maxillary incisor to NA line, and mandibular incisor to NB line showed statistically significant differences. All measurements were within the limits of agreement based on the Bland-Altman plots. The widths of limits of agreement were wider in dental measurements than those in the skeletal measurements. Conclusions Automatic cephalometric analyses based on convolutional neural network may offer clinically acceptable diagnostic performance. Careful consideration and additional manual adjustment are needed for dental measurements regarding tooth structures for higher accuracy and better performance.

Dimorphism in Dental Tissues: Sex differences in Archaeological Individuals for Multiple Tooth Types

ObjectivesDimorphism in the dentition has been observed in human populations worldwide. However, research has largely focused on traditional linear crown measurements. As imaging systems, such as micro-computed tomography (micro-CT), become increasingly more accessible, new dental measurements such as dental tissue size and proportions can be obtained. This research investigates the variation of dental tissues and proportions by sex in archaeological samples.Materials and MethodsUpper and lower first incisor to second premolar tooth rows were obtained from 30 individuals (n=300), from 3 archaeological samples. The teeth were micro-CT scanned and surface area and volumetric measurements were obtained from the surface meshes extracted. Dental wear was also recorded and differences between sexes determined.ResultsEnamel and crown measurements were found to be larger in females. Conversely, dentine and root measurements were larger in males.DiscussionThe findings support the potential use of dental tissues to estimate sex of individuals from archaeological samples, whilst also indicating that individuals aged using current dental ageing methods may be under- or over-aged due to sex differences in enamel thickness.

Estimating Chronological Age by Dental Measurements on the Periapical Radiographs of an ‎Iranian Adult Population

Background: This study aimed to assess the accuracy of chronological age estimation based on dental measurements made on the Periapical (PA) radiographs of an Iranian adult population. Methods: This study evaluated 90 parallel PA radiographs of sound maxillary canine teeth of 39 males and 51 females. Tooth length, root length, pulp length, pulp width, and root width at points A, B, and C according to Kvaal’s method were measured on PA radiographs using Scanora software. The collected data were analyzed using SPSS. Results: Maximum root width at point A provided the highest accuracy for gender estimation (77.7%). A significant correlation was noted between maximum pulp width at points B and C with age. Besides, a regression formula for age estimation was obtained. Conclusion: Maximum pulp width at points B and C could be used for age estimation in the adult population besides other parameters.

Estimating Chronological Age by Dental Measurements on the Periapical Radiographs in Iranian Adults

Objectives: This study aimed to assess the accuracy of chronological age estimation based on dental measurements made on periapical (PA) radiographs of an Iranian adult population. Materials and Methods: This study evaluated 90 parallel PA radiographs of sound maxillary canine teeth of 39 males and 51 females. Tooth length, root length, pulp length, pulp width and root width at points A, B and C according to the Kvaal’s method were measured on PA radiographs using Scanora software. Data were analyzed using SPSS. Results: Maximum Root width at point A had the highest accuracy for sex estimation (77.7%). A significant correlation was noted between maximum pulp width at points B and C with age and a regression formula for age estimation was obtained. Conclusion: Maximum pulp width at points B and C can be used for age estimation in adult population beside other parameters.