Frequency and variability of five non metric dental crown traits in the permanent maxillary dentitions of a racially mixed population from Bengaluru, Karnataka

Frequency and variability of nonmetric dental crown traits of primary and permanent molars in a group of orthodontic patients

BACKGROUND

The present study aimed to assess the frequency and variation of 13 nonmetric dental crown traits (NDCT) in permanent and primary molars in German orthodontic patients.

METHODS

Dental records from orthodontic patients were screened and evaluated. First and second permanent and primary upper and lower molars (from left and right sides) were assessed. Teeth with cavitated dental caries, occlusal wear, restorations and obvious dental deformities were not evaluated. The NDCT for permanent molars were identified and scored according to the odontoscopic system developed by Arizona State University Dental Anthropology System (ASUDAS). The NDCT for primary molars were identified and scored according to ASUDAS, Hanihara's method and Sciulli's method. The χ2 test was used to investigate side preference and sexual dimorphism at a significance level of p ≤ 0.050.

RESULTS

A total of 163 orthodontic patients (82 males and 81 females) aged 8-14 years were included. A sexual dimorphism was observed for the hypocone in first upper permanent molar (p = 0.041). The protostylid was observed in lower permanent molars (range 2.1-10%). Males presented more hypoconulid than females (p = 0.019). Only females presented the distal trigonid crest in lower first permanent molars (p = 0.002). The most common groove pattern in primary molars was Y; male presented more Y grade than females in the lower second primary molar (p = 0.039). Asymmetry was observed in some traits, ranging from 0 to 100%.

CONCLUSION

The present study showed the frequency of NDCT of molars in German orthodontic patients and demonstrated that some traits present sexual dimorphism.

Dental Anomalies: An Identification Marker in Forensics

Aim This study aims to evaluate the non-morphological traits of the South Indian population. Introduction Dental morphological traits, also known as non-metric dental traits, exhibit variation in appearance both within and between groups. The study analyzed the non-metric traits among the South Indian population, as few variants can be grouped within the population.  Materials and methods A total of 500 extracted tooth samples were collected. The dental non-metric traits that were evaluated are the cusp of Carabelli (CC), Talon's cusp (TC), shoveled incisor (SI), peg-shaped lateral incisor (PL), protostylid (PR), Dryopithecus pattern groove (DP), hypoconulid (HY), parastyle (PA), multiple parastyle (MPA), paracone (PC), Bushman's canine (BC), interruption groove (IG), tuberculum dentale (TD), tuberculum intermedium (TI), radix entomolaris (RE), fusion (F), radiculous premolar (RP), dilaceration (D), dens evaginatus (DE), and enamel pearl (EP).  Results Out of 20 dental non-metric traits that were evaluated in the study, 14 traits were identified to be common within the population. The prevalence were as follows: cusp of Carabelli (52%), shoveled incisor (8.2%), peg-shaped lateral incisor (7.4%), parastyle (0.8%), multiple parastyle (0.2%), Bushman's canine (0.4%), interruption groove (2.2%), tuberculum intermedium (0.6%), radix entomolaris (39.6%), fusion (2.8%), radiculous premolar (0.2%), dilaceration (58.2%), dens evaginatus (1.2%), and enamel pearl (0.8%) among the South Indian population.  Conclusion The current study was discovered to have more Carabelli traits, shoveled incisors, radix entomolaris, and dilaceration than other non-metric features. This shows that these characteristics are more prevalent in the South Indian population, which could be one of the strategies used to validate human identification in a forensic context.

The Prevalence and Association of Non-metric Dental Traits With Dentoskeletal Malocclusion and ABO Blood Groups in the Maharashtrian Population

Introduction Non-metric dental traits (NMDTs) are a fundamental data source in forensic dentistry. Nevertheless, the insufficiency of data regarding the occurrence of these traits has instigated the present research endeavor aimed at ascertaining the prevalence, sexual dimorphism, and extent of inter-trait correlations within the Maharashtrian population of India. The secondary objective was to determine the correlations between NMDTs, dentoskeletal malocclusion, and ABO blood groups. Materials and methods This prospective, observational study included 528 individuals aged 18-30 years with dentoskeletal Class I, II, and III malocclusions. NMDTs such as the presence of Cusp of Carabelli (CoC) on the upper first molars, hypocone on the upper second molars, and tri- or bicuspid lower second premolars were observed on the dental casts of all individuals. The dental relationship was assessed clinically according to Angle's system for the classification of malocclusion. The skeletal relationship was assessed using lateral cephalograms of the individuals. ABO blood groups were obtained from their medical records. The Chi-square test of independence was used to assess the associations between various variables. The correlation between each measurement was determined using Spearman's correlation test. Multivariate analysis enabled the identification of parameters that exhibited independent associations with NMDTs. A multinomial logistic regression model was constructed using NMDTs as the outcome variable. Results The mean age of males was 20.82 ± 1.71 years and 21.15 ± 1.76 years was in females. NMDTs were predominantly seen in females (n=394, 75%), with Class II dentoskeletal malocclusion (n=265, 50%) and B blood group ((n=199, 38%). All traits showed bilateral predominance. A statistically significant association was found between CoC, dentoskeletal malocclusion, hypocone, and tricuspid lower second premolars (p <0.05). All NMDTs showed a negative correlation with sex, a positive correlation between age and the presence of hypocones and CoC, a negative correlation between age and tricuspid lower second premolars, a strong positive correlation with dentoskeletal malocclusion, and a weak positive correlation with ABO blood groups. Multinomial logistic regression model analysis revealed that none of the independent variables were statistically significant predictors of the presence of CoC and tricuspid lower second premolars, while dentoskeletal malocclusion and sex were significant predictors of the presence of the hypocone trait. Conclusion NMDTs showed a female predilection with bilateral predominance. A significant association was observed between these traits and dentoskeletal malocclusions. The most commonly observed NMDT was the presence of a hypocone on the upper second molars, followed by the tricuspid lower second premolars and the CoC.

Effect of Geographic Variation in Bioarcheology: A Forensic Odontology Perspective

How to cite this article: Yukta HN, Augustine D, SV Sowmya. Effect of Geographic Variation in Bioarcheology: A Forensic Odontology Perspective. J Contemp Dent Pract 2024;25(1):1-2.

Evaluation of Twenty Non-Metric Dental Crown Traits in Different Types of Malocclusions in a Sample from India, New Delhi Population

Background

Dental phenotype shows variation in the form of various metric and non-metric traits, primarily due to gene-environment interplay. It gives an insight into the evolutionary trends, ancestry, and food habits. Recently, it has been explored for genetic affinity with several growth anomalies and development of craniofacial skeleton which is also responsible for dental and skeletal malocclusions.

Objectives

the current study aims to investigate the non-metric dental crown traits (NDCTs) using Arizona State University Dental Anthropology system (ASUDAS) in different types of malocclusions in Delhi, National Capital Region (NCR) population.

Materials and methods

The study design was observational and retrospective. The total sample comprised of 240 pairs of dental casts divided into four equal groups of 60 subjects each (30 male and 30 female), based on malocclusion. The four groups of malocclusions were: Angle's Class I, Class II division 1, Class II division 2, Class III. The investigator was blinded for patient ID and sex before recording the data. The data for cast were recorded by three observers independently in a modified malocclusion- non-metric dental crown traits (M-NDCT) anthropological variants chart and statistically analyzed for association with different malocclusions and sex.

Results

Significant differences were found in the expression of several NDCTs (both in presence and scoring) in different malocclusions. Class I malocclusion showed a predominantly winging, shoveling -upper central and lateral incisor, protostylid, hypoconulid absence in lower second molar, and cusp number. Class II malocclusion showed a double shoveling, interrupted groove, tuberculum dentale, canine mesial ridge, premolar accessory cusp, Carabelli's trait, lingual cusp variation, and seventh cusp in the lower left first molar. Class III malocclusion showed the absence of hypocone in upper second molar, deflecting wrinkle, distal trigonid crest, and Y groove in left lower second molar (26.7%). Besides, sexual dimorphism was seen in shoveling -upper central and lateral incisor, canine mesial ridge, Carabelli's trait, 3-cusp in upper second molar, and cusp number.

Conclusions

Significant association was found between non-metric dental traits and malocclusions (Class I, Class division 1, Class II division 2, and Class III). Significant sex-linked differences were also found. Further studies can be performed at multicenter pan-India level with a standard robust protocol and a large sample.

Study of twenty non-metric dental crown traits using ASUDAS system in NCR (India) population

Background

The non-metric dental crown traits (NDCT) can vary within and between the geo-populations. These play a critical role in the ethnicity determination and help in identification of an individual. A commonly used system for scoring these dental traits is “Arizona State University Dental Anthropology System” (ASUDAS).

Aim and objectives

Our study aims to evaluate the frequency trend of twenty NDCT traits in the India, National Capital Region population using ASUDAS, and check for any significant sexual dimorphism for each trait.

Methods

The maxillary and mandibular dental casts from 200 patients (100 males+100 females, age 18–30 years) reporting to the dental OPD of a Government dental college were evaluated. Twenty dental crown traits were scored as per ASUDAS protocol in each dental cast by three investigators independently. NDCTs were tabulated and the chi-square test was performed for calculation of the P value.

Results

The results showed that the trait cusp number (83%) and lingual cusp variation (79%) were the two most frequent NDCTs and Y groove pattern (13%) and premolar accessory cusp-4 (12.5%) were the two least frequent traits observed. Shoveling of the upper lateral incisor (P=0.007), tuberculum dentale (P=0.049), mesial ridge (lingual) (P=0.034), and hypocone absence (P=0.001) were found to show statistically significant sexual dimorphism (P < 0.05). Although grade-wise expression of shoveling in upper lateral had statistically significant sexual dimorphism and the frequency of higher expression grades was found more in females, overall dichotomy of expression was not significant. Similarly, although an expression of grade-wise tuberculum dentale, mesial ridge (lingual) and hypocone absence had statistically significant sexual dimorphism, an overall dichotomy of expression was not significant.

Conclusion

The current study shows certain NDCTs like cusp number and lingual cusp variation have a significant association with the NCR population. Sexual dimorphism was not significant; hence, future studies should be planned on a large sample with sex pooled data for each precise location and ethnicity in all the regions of India. This can be further correlated with different facial forms and dental occlusal patterns, for correlation with abnormalities in jaws and teeth.

Variability and Patterning in Permanent Tooth Dimensions among Four Ethnic Groups from the North-eastern States of India

Methods

The study was a comparative cross-sectional study among four different ethnic groups of North-east India among the age group of 20-30 years. Dimensions of the maxillary and mandibular teeth were measured with a digital Vernier calliper using the dental casts of 50 male and 50 female subjects from each of the four ethnic groups under study. The data were statistically analyzed using a Student's t-test and one-way analysis of variance. Statistical significance was set at p < 0.05.

Results

The tooth dimensions of all four ethnic groups were significantly lower than the standard values except for the MD dimension of the maxillary second molars of the Singpho group (9.13 mm vs. 9.0 mm); mandibular central incisors of the Meitei group (5.01 mm vs. 5.0 mm); and mandibular lateral incisors of the Meitei, Ao, and Singpho groups (>standard value of 5.5 mm) and BL dimension of the mandibular first premolars of the Meitei and Ao groups (>standard value of 7.5 mm); mandibular second premolars of the Meitei and Singpho groups (>standard value of 8.0 mm); and mandibular second molars of the Ao group (10.04 mm vs. 10.0 mm). In some instances, the comparative analysis revealed group variations in different tooth dimensions among the four ethnic groups (p < 0.05).

Conclusion

Variations were observed in the tooth dimensions among the four ethnic groups and within the same population. Unlike other parts of India, the North-eastern population belongs to a distinct ethnic race of indigenous people of East Asia, Southeast Asia, and the Arctic region of North America. Hence, population-specific data for India's North-eastern region are necessary for forensic odontology, dental anthropology, routine dental practice, and effective treatment planning.