The discriminative potential of palatal geometric analysis for sex discrimination and human identification

Previous 3D superimposition studies of digital scans of the human palate, using geometric and surface morphology comparisons, have shown its usefulness in assisting in the identification process, including its ability to distinguish identical twins. This study aimed to evaluate the discriminative potential when only simple geometric analysis is used. Its aim is not only to determine if geometric comparison alone is sufficient not only to assist in identification but if it supports the hypothesis of assisting in sex discrimination when no other comparative data is available. The palates of 64 monozygotic (M.Z.T.) and 39 dizygotic (D.Z.T.) twins were digitized three times using a scanner. Digital smoothing was used to remove the rugae, and palatal height, depth, and width were measured. The study confirmed that the smoothing function had little effect on the discriminatory function since the Mean Absolute Distance (MAD) between M.Z.T. (0.430 ± 0.018 mm versus 0.425 ± 0.022 mm p = 0.061) or D.Z.T. (0.621 ± 0.058 mm versus 0.586 ± 0.053 mm, p = 0.284) scans show little change. By combining the height, depth, and width into a discriminative function, the sex correctly correlated 83.9% of the time, identity by 91.2% sensitivity, and twining by 68.5%. The difference in the 3D palatal model between twin siblings is primarily due to palate geometrics. Since geometric comparison requires far less computation time, geometric comparison alone can be used as an adjunct metric for limiting the possible matches in a dental 3D database in determining both sex and identity, especially if no other evidence is available.

Effect of Palatal Vault Depth on the Trueness of Metal Laser-Sintered and Cast Cobalt-Chromium Removable Partial Denture Frameworks

PURPOSE

This in vitro study compares the trueness of removable partial denture cobalt-chromium (Co-Cr) frameworks fabricated by 3D-printed pattern casting and those fabricated by selective laser sintering (SLS) of different palate vault depths.

MATERIALS AND METHODS

A partially edentulous Kennedy class II mod.1 maxillary model with a deep palatal vault was used, which was modified and duplicated to produce another model with medium palatal vault depth. After model scanning, the partial denture framework was designed using CAD software to fabricate 20 removable partial denture (RPD) frameworks. For each model, two types of frameworks were fabricated. For the 1^st type, the 3D-printed resin patterns were formed using a 3D printer, and then casting was performed (AM-cast framework). For the 2^nd type, a direct metal laser sintering machine was used for the RPD frameworks fabrication (SLS framework). 3D scanning of fabricated frameworks was performed, and the standard tessellation language (STL) file was superimposed over the STL file from the original design, and the average deviation was recorded. Data were statistically analyzed.

RESULTS

Two-way ANOVA test was used, followed by the least significant difference (LSD) for pair-wise comparisons to estimate any significant differences between groups. The RPD frameworks with high palatal vault depth represent larger discrepancies mean value than that with the medium palatal vault depth with a highly significant statistical difference. SLS shows less deviation than AM-cast CO-Cr frameworks with highly significant statistical differences whatever palatal vault depth.

CONCLUSION

RPD metal frameworks fabricated with SLS have better accuracy compared to those fabricated by AM-cast, regardless of the depth of the palatal vault. This article is protected by copyright. All rights reserved.

Three-Dimensional Evaluation of the Tongue Volume in Different Dentoskeletal Patterns - A Cone Beam Computed Tomographic Study

AIM

The aim of this study is to evaluate tongue volume using cone-beam computed tomographic (CBCT) and its correlation to different growth patterns in patients.

MATERIALS AND METHODS

Sixty preorthodontic records of CBCT scans of subjects ranging from 14 to 25 age group from retrospective data of department were selected for the study. Patients were classified into three groups based on angle FMA; Group I (n = 20) with average growth pattern (FMA 22°-28°); Group II (n = 20) vertical growth pattern (FMA >28°); Group III (n = 25) horizontal growth pattern (FMA <20°). Tongue volume evaluation was done using Myrian® Software. Dentoskeletal features and parameters related to archform such as palatal vault depth, interpremolar, and intermolar distance were evaluated in all the subjects. ANOVA test was used for intergroup comparison of tongue volume and dentoskeletal parameters in all three groups. Correlation of the tongue volume to dentoskeletal parameters was done using Pearson's correlation test.

RESULTS

Mean tongue volume in Group I was 66.10 cm3, Group II, 66.04 cm3 and Group III was 66.72 cm3. There was a statistically significant correlation (P < 0.5) of tongue volume with palatal vault width, maxillary length, and mandibular interpremolar and intermolar distance among dentoskeletal parameters.

CONCLUSION

Tongue volume was found equal in all groups despite the variation in growth patterns. Skeletal differences leading to different growth patterns were found to be related to mandibular morphology. The results indicate the indirect role of the tongue in causing malocclusion in orthodontic patients.

Which oropharyngeal factors are significant risk factors for obstructive sleep apnea? An age-matched study and dentist perspectives

OBJECTIVE

Obstructive sleep apnea (OSA) is a common sleep breathing disorder. Untreated OSA may lead to a number of cardiovascular complications. Dentists may play an important role in OSA detection by conducting careful oral examinations. This study focused on the correlation of oral anatomical features in Thai patients who presented with OSA.

METHODS

We conducted a prospective comparative study at a sleep/hypertension clinic and a dental clinic at Khon Kaen University in Thailand. Patients with OSA were enrolled in the study, along with age-matched patients with non-OSA (controls). Baseline characteristics, clinical data, and oropharyngeal data of all patients were compared between the two groups. Oropharyngeal measurements included tongue size, torus mandibularis, Mallampati classification, palatal space, and lateral pharyngeal wall area. Multivariate logistic regression analysis was used to identify the factors associated with OSA.

RESULTS

During the study period, there were 156 patients who met the study criteria; 78 were patients with OSA and the other 78 were healthy control subjects. In the OSA group, there were 43 males with a mean age of 53 (standard deviation 12.29) years and a mean BMI of 30.86 kg/mm(2). There were 37 males in the control group with a mean age of 50 (standard deviation 12.04) years and a mean BMI of 24.03 kg/mm(2). According to multivariate logistic analysis, three factors were perfectly associated with OSA, including torus mandibularis class 6, narrow lateral pharyngeal wall, and Mallampati class 4. There were two other significant factors associated with having OSA, namely, BMI and Mallampati classification. The adjusted odds ratios (95% confidence interval) of these two factors were 1.445 (1.017, 2.052) and 5.040 (1.655, 15.358), respectively.

CONCLUSION

Dentists may play an important role in the detection of OSA in patients with high BMI through careful oropharyngeal examination in routine dental treatment. A large torus mandibularis, Mallampati class 4, and a narrow lateral pharyngeal wall are important anatomical risk factors for OSA.

Gender identification and morphologic classification of tooth, arch and palatal forms in Saudi population

AIMS

To determine various tooth form, arch form, and palatal form with gender identification between males and females of the Saudi population.

MATERIALS AND METHODS

Irreversible hydrocolloid impressions were made of the maxillary teeth of 100 dentate male and female subjects to obtain study casts. A standardized procedure was adopted to photograph the maxillary dental arches and the maxillary central incisors on the study casts taken from each subject. The outline form of tooth, arch, and palatal form were determined using a standardized method. The average of six prosthodontist's evaluation was considered who classified the outline tracings visually. The statistical analysis was performed using Chi-Square and results tabulated.

RESULTS

The predominant tooth is combination form in males and ovoid form in females, the predominant arch is ovoid form in males and square form in females and the predominant palatal form are both U and V shaped in males and U-shaped in females.

CONCLUSION

Except for the tooth form there was a significant difference with arch and palatal form among males and females of the population group studied. The determined tooth, arch and palatal forms are useful in selection and arrangement of artificial teeth among Saudi edentulous population group. Generalizing from the study is questionable as the sample size is small. Further studies should be conducted in a larger sample to confirm the study results.