Construction of 13-locus X-STR multiplex PCR system that reinforces Argus X-12 kit discrimination capacity: Application to the Malay population.

Closely linked groups of markers on the X chromosome are very useful for testing complex kinship relationships involving X-STR transmission. The Argus X-12 kit, a unique commercially available kit, can obtain haplotypes of 4 linkage groups (LGs) consisting of 3 markers. Although many population data have been reported for forensic purposes, differences in discrimination ability exist between LG1 and LG2, 3, and 4 in East Asian populations, and the data of this kit would become more useful if the discrimination ability of the latter groups were increased. Therefore, for matches found using this kit for some linkage group data, then to increase the identification ability, we additionally introduced 13 X-STR loci and established a method allowing comparison using data from 25 loci. The 13X-STRs add two locus data to each of LG2, 3, and 4, and also add two closely linked group (CLG) data between LG2 and 3 and LG3 and 4 in one multiplex PCR. Assessment of this method for a Malay population for which data by Argus X-12 had already been reported showed that the frequencies of distinct haplotypes in LG2, 3, and 4 were increased by 33.0-42.6 %, and frequencies of unique haplotypes increased by 45.4-59.2 %. The respective haplotype diversity values of the additional 3-locus and 4-locus CLGs were 0.9838 and 0.9939, which helps to improve discriminatory power and to predict recombination locations on the X chromosome. Although we have been testing these loci with Japanese subjects, this system would also be useful for the Malay population.

Three-dimensional surface area analyses of developing maxillary second premolar root apices for age estimation using CBCT images.

Three-dimensional surface area analyses of developing root apices for age estimation in children and young adults have shown promising results. The current study aimed to apply this three-dimensional method to develop a regression model for estimating age in Malaysian children aged 7 to 14 using developing maxillary second premolars. A training sample of 155 cone-beam computed tomography scans (83 Malays and 72 Chinese) was analysed, and the formula was subsequently validated on an independent sample of 92 cone-beam computed tomography scans (45 Malays and 47 Chinese). The results showed a strong correlation (r = 94 %) between the chronological age as a dependent variable and the predictor variables, including root surface area of the apex, sex, ethnicity, and root development status (open/closed apices). For this model, the predictor variables accounted for 88.4 % of the variation in age except sex and ethnicity. A mean absolute error value of 0.42 indicated that this model can be reliably used for Malaysian children. In conclusion, this study recognises the method of three-dimensional surface area analyses as a valuable tool for age estimation in forensic and clinical practice. Further studies are highly recommended to assess its effectiveness across different demographic groups.

Middle mesial canal in mandibular first molar: A narrative review.

Purpose: This review aimed to assess the incidence, anatomical characteristics, identification, and clinical management using conventional techniques and advanced tools to manage MMCs successfully. Methods: Medline/PubMed and Scopus databases were searched using "Middle mesial canal," "Middle mesial root canal," OR "Accessory mesial canal" keywords from 1 January 1970 and 1 February 2023. The most pertinent articles were chosen for the review from the retrieved articles. In addition, relevant articles were added by manually searching the list of references. Results: The incidence of MMC is noticeable in younger people, and the confluent canal is the most common type. The majority of MMCs merged with mesiobuccal (MB) canals rather than mesiolingual (ML) canals. Clinical management could be employed using the standard endodontics protocol, and recent radiography technologies, magnification, rotary, and obturation materials can facilitate the procedures. Conclusion: The possibility of the incidence of MMC is not unusual. Detection and thorough debridement followed by obturation of the canal could increase the success rate of clinical outcomes.

The groove configuration of mandibular molars of malaysians of mongoloid ancestry / Configuración del surco de los molares mandibulares de los malayos de ascendencia mongoloide

Aim: Variation in dental structures is widely accepted as a combination of multiple factors such as gender, environmental effects and genetics. However, the characterization of similarities and differences in dental morphology has been lacking in relation to the factors mentioned. This study aims to assess and compare the variations in traits in mandibular molars and the influence of gender and ethnicity in affecting these traits amongst the Malaysian population of Mongoloid ancestry. Materials and Methods: Our study population was 180 dental casts of patients, from 15 to 40 years old, comprising 56 Malays and 124 Chinese; 60 were males and 120 were females. Traits like groove pattern, number of cusps, protostylids and deflecting wrinkles were observed, scored, and recorded. Results: This study revealed that the most common mandibular first molar (M1) was characterized by 5 cusps and displayed 'Y' groove pattern, while the most common mandibular second molar (M2) had 4 cusps and exhibited a groove pattern that resembled a '+'. Notably, all the traits studied were bilaterally symmetrical, except for the groove pattern of M1, while sexual dimorphism was observed in groove patterns of M2. Conclusions: This study found that M1 had a preponderance of 5 cusps with 'Y' groove pattern, while M2 were typically 4-cusped with '+' groove pattern.

Objetivo: La variación en las estructuras dentales es ampliamente aceptada como el resultado de una combinación de múltiples factores como el género, los efectos ambientales y la genética. Sin embargo, ha faltado la caracterización de similitudes y diferencias en la morfología dental en relación a los factores mencionados. Este estudio tiene como objetivo evaluar y comparar las variaciones en los rasgos de los molares mandibulares y la influencia del género y la etnia al afectar estos rasgos entre la población malaya de ascendencia mongoloide. Materiales y Métodos: Nuestra población de estudio fue de 180 modelos dentales de pacientes, de 15 a 40 años,conformados por 56 malayos y 124 chinos; 60 eran hombres y 120 eran mujeres. Se observaron, puntuaron y registraron rasgos como el patrón de surcos, el número de cúspides, los protostílidos y las arrugas desviadas. Resultados: Este estudio reveló que el primer molar mandibular más común (M1) se caracterizaba por 5 cúspides y mostraba un patrón de ranura en 'Y', mientras que el segundo molar mandibular más común (M2) tenía 4 cúspides y exhibía un patrón de ranura que se parecía a un ' +'. En particular, todos los rasgos estudiados eran bilateralmente simétricos, excepto el patrón de surco de M1, mientras que se observó dimorfismo sexual en los patrones de surco de M2. Conclusión: Este estudio encontró que M1 tenía una preponderancia de 5 cúspides con un patrón de ranura en 'Y', mientras que M2 tenía típicamente 4 cúspides con un patrón de ranura '+'.

Dental age estimation of Malaysian Indian children and adolescents: applicability of Chaillet and Demirjian's modified method using artificial neural network.

BACKGROUND: Recognising the importance of dental age (DA) estimation in forensic investigations, a variety of methods abound in the literature due to population-specific attributes. A reference eight-tooth method developed by Chaillet and Demirjian estimated the DA of children and adolescents. AIM: This study aims to investigate the applicability of Chaillet and Demirjian's method among Malaysian Indians aged 5.00-17.99 years. SUBJECTS AND METHODS: Dental panoramic tomographs of Malaysian Indians aged 5.00-17.99 years were statistically analysed using paired t-test and artificial neural networks multilayer perceptron (ANN-MLP). RESULTS: A total of 1015 dental panoramic tomographs were analysed. Paired t-test analysis against the reference dental maturity scores revealed underestimation of DA in boys of 1.68 years and girls of 2.56 years indicating inaccurate age estimation. A population-specific prediction model with a new set of dental maturity scores was established on Chaillet and Demirjian's scores using ANN-MLP. The new dental maturity scores showed accurate estimation of DA with differences between CA and DA being 12 and 25 days for boys and girls, respectively. Furthermore, a new DA prediction formula was developed using regression analysis following the establishment of new dental scores based on ANN-MLP. CONCLUSION: A novel Malaysian Indian-specific prediction model that demonstrated accurate DA estimation was established.

A comparative study on mandibular premolar root canal morphology employing cone-beam computed tomography and microcomputed tomography imaging.

Aim: The present study was to investigate the root canal morphology of mandibular premolars in Malaysian population using cone-beam computed tomography (CBCT) and microcomputed tomography (micro-CT) scanned images. Materials and Methods: Sixty selected mandibular premolars were evaluated in vitro and the root canal morphologies of the samples were categorized based on Vertucci's classification. The position of apical foramen, presence, and location of lateral canal, as well as prevalence of apical delta, were also determined. Results: Invariably, Type I variety (Vertucci's classification) was the most frequent root canal morphology followed by Type V and Type III after micro-CT imaging. CBCT investigation also revealed Type I as the most numerous; however, the second most common configuration was Type III followed closely by others. There was a moderate agreement in Vertucci's classification of root canal configuration and also prevalence of apical delta (kappa: 0.516 and 0.550, respectively). However, only a fair agreement (kappa: 0.289) was observed between CBCT and micro-CT on the prevalence of lateral canal. Conclusion: CBCT should be cautiously used in determining root canal configuration as deficiencies were evident and revealed during micro-CT imaging.

Dental age estimation of Malaysian children: a comparison of two-dimensional versus three-dimensional imaging analyses of the developing root apices.

AIM: This study compared the effectiveness of the three-dimensional (3D) cone beam computed tomography (CBCT) method of age estimation developed by Asif et al. with two-dimensional Cameriere's method. SUBJECTS AND METHODS: CBCT images belonging to 129 Malaysian Chinese and Malay ethnic groups aged 7-14 years were investigated and analysed. RESULTS: The results indicated a strong correlation between chronological age and the predictor variables for both Cameriere's (r = 0.984) and Asif's (r = 0.988) methods of age estimation. Fisher Z test analysis indicated no statistically significant difference in the correlation values between the two methods. Mean absolute error (MAE) value of 0.613 was observed for Cameriere's and 0.290 was observed for Asif's method. CONCLUSIONS: The results indicated that the methods of age estimation from both Asif et al. and Cameriere et al. are applicable on Malaysian children. However, Asif et al.'s 3D CBCT method of age estimation resulted in greater accuracy and reliability in estimating chronological age.

Cosmetic "Gold Thread Therapy": A Nuisance That Decreases the Diagnostic Quality of a Dental Panoramic Image.

During routine imaging of the craniofacial region, it is recognised that some "cosmetic" procedures with metallic insertions can be revealed radiographically. These objects however make it difficult to obtain a good interpretation of anatomical structures for management of diseases. A 58-year-old female patient visited a private dental facility in Kuala Lumpur for prosthodontic replacement of missing teeth. The dental panoramic image revealed generalized bone loss and numerous unusual multiple thread-like radioopacities. These gold threads made radiographic evaluation difficult and complicated the process of treatment planning for dental implant placement advocated for this patient.

Age estimation from developing third molars.

We investigated the development of third molars among Malaysians (including variations between jaws and genders) using Demirjian's method. Dental panoramic radiographs of 1224 subjects aged 8 to 24 years were examined, and the molars were assigned Demirjian et al.'s development grades (A-H). Results indicated that 18.8% had congenitally missing or extracted third molars. Development of molars begins earlier in females (also in the mandible), but by age 9, male children's molar development speeds up with more advanced grades in their middle teens than females. Grade C indicates the subject is a juvenile, while initiation of root development (Grade E), was observed from 13 years on. Grade H can occur in a child aged 18 years who technically is still a juvenile. We compared the development and growth patterns of the third molar from both the maxilla and the mandible.

Population Genetics in Malaysia and Japanese Populations Using Power Plex Y23 System.

Population flow between Southeast Asian countries and Japan continues to gather pace. Accordingly, the number of foreigners involved in incidents in Japan has markedly increased, which means that forensic dentistry is now increasingly being faced with the need to analyze DNA from persons of non-Japanese extraction. The DNA test currently used for personal identification mainly utilizes short tandem repeats (STRs) on autosomal chromosomes and the Y-chromosome. This test was developed for use in personal identification, not for distinguishing among races; nonetheless, the standard method for personal identification is often used because the procedure has been established. To determine the degree to which racial differences can be distinguished by standard DNA analysis, 23 STRs located on the Y chromosome were investigated in 218 Malay and 426 Japanese males. The frequencies of each STR were calculated in the two populations. The difference in the power of discrimination between the Malay and Japanese populations ranged from a minimum of 0.01 to a maximum of 0.27; the difference in polymorphic information content ranged from 0.01 (minimum) to 0.23 (maximum). No major differences were noted in the polymorphisms in these two Mongoloid populations, but the distributions of the 17 STRs differed significantly. Short tandem repeat types demonstrating a likelihood of racial differences were identified in 14 of the STRs. Race-specific STR types were identified in 10 STRs. These results suggest that the likelihood of Malay or Japanese genetic background can be judged based on Y-chromosome STR test results.

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.

Enhancing the three-dimensional visualization of a foreign object using Mimics software.

A patient was referred to the Oral and Maxillofacial Imaging Division and the attending dental specialist suspected a foreign object at the anterior region of the maxilla. The region was scanned using Kodak 9000 3D cone-beam computed tomography (CBCT) extraoral imaging system (Carestream Health, Inc.) to determine the type and morphometric characteristic of foreign object. The CBCT images failed to determine the identity and nature of the foreign object. CBCT images were then exported to the Materialise Interactive Medical Image Control System (Mimics) software to evaluate whether this software can help in enhancing the visualization of the foreign object in the maxillofacial region. The findings showed that there was an improved visualization of the foreign body and the type of the object could be determined with certainty. The object was identified as an endodontic file and was clearly visible when visualized as a reconstructed 3D model in Mimics software. Although the identification of abnormalities has been dramatically improved using 3D scans, the visualization can be further enhanced using image processing software like Mimics.

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.

Determining the Accuracy of the Mandibular Canal Region in 3D Biomodels Fabricated from CBCT Scanned Data: A Cadaveric Study.

OBJECTIVE: To validate the accuracy of the mandibular canal region in 3D biomodel produced by using data obtained from Cone-Beam Computed Tomography (CBCT) of cadaveric mandibles. METHODS: Six hemi-mandible samples were scanned using the i-CAT CBCT system. The scanned data was transferred to the OsiriX software for measurement protocol and subsequently into Mimics software to fabricate customized cutting jigs and 3D biomodels based on rapid prototyping technology. The hemi-mandibles were segmented into 5 dentoalveolar blocks using the customized jigs. Digital calliper was used to measure six distances surrounding the mandibular canal on each section. The same distances were measured on the corresponding cross-sectional OsiriX images and the 3D biomodels of each dentoalveolar block. RESULTS: Statistically no significant difference was found when measurements from OsiriX images and 3D biomodels were compared to the "gold standard" -direct digital calliper measurement of the cadaveric dentoalveolar blocks. Moreover, the mean value difference of the various measurements between the different study components was also minimal. CONCLUSION: Various distances surrounding the mandibular canal from 3D biomodels produced from the CBCT scanned data was similar to that of direct digital calliper measurements of the cadaveric specimens.

Dental age estimation in Malaysian adults based on volumetric analysis of pulp/tooth ratio using CBCT data.

Forensic odontology plays an important role in human identification and dental age estimation is an integral part of this process. The aim of the study was to investigate the association between chronological age and pulp/tooth volume ratio in a Malaysian population (Malays and Chinese) from cone-beam computed tomography (CBCT) scans, enhanced with Mimics software. Three hundred CBCT scans of 153 males and 147 females, aged between 16 and 65 years were divided into 5 age groups. Volumetric analysis of the pulp/tooth ratio was performed in maxillary left canines, maxillary right canines and maxillary right central incisors. Simple linear regression and Pearson correlation analysis indicated the strongest coefficient of correlation (R) values for maxillary right central incisors (0.83) followed by maxillary right canines (0.74) and maxillary left canines (0.73). Fisher's Z test indicated that dental age estimation is gender independent. The derived regression equations were further validated on an independent group of 126 teeth. The results indicated mean absolute error (MAE) values of 6.48 and 8.58 years for maxillary right central incisors and maxillary canines respectively. It was also noticed that MAE values were higher among the age groups ranging from 46 to 65 years. This study showed that a volumetric change in the pulp cavity with age is a valuable assessment method for dental age estimation among Malaysian population.

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.

Dental age estimation employing CBCT scans enhanced with Mimics software: Comparison of two different approaches using pulp/tooth volumetric analysis.

The methods of dental age estimation and identification of unknown deceased individuals are evolving with the introduction of advanced innovative imaging technologies in forensic investigations. However, assessing small structures like root canal volumes can be challenging in spite of using highly advanced technology. The aim of the study was to investigate which amongst the two methods of volumetric analysis of maxillary central incisors displayed higher strength of correlation between chronological age and pulp/tooth volume ratio for Malaysian adults. Volumetric analysis of pulp cavity/tooth ratio was employed in Method 1 and pulp chamber/crown ratio (up to cemento-enamel junction) was analysed in Method 2. The images were acquired employing CBCT scans and enhanced by manipulating them with the Mimics software. These scans belonged to 56 males and 54 females and their ages ranged from 16 to 65 years. Pearson correlation and regression analysis indicated that both methods used for volumetric measurements had strong correlation between chronological age and pulp/tooth volume ratio. However, Method 2 gave higher coefficient of determination value (R2 = 0.78) when compared to Method 1 (R2 = 0.64). Moreover, manipulation in Method 2 was less time consuming and revealed higher inter-examiner reliability (0.982) as no manual intervention during 'multiple slice editing phase' of the software was required. In conclusion, this study showed that volumetric analysis of pulp cavity/tooth ratio is a valuable gender independent technique and the Method 2 regression equation should be recommended for dental age estimation.

Correlation between numbers of cells in human dental pulp and age: Implications for age estimation.

OBJECTIVE: The aim of this study was to investigate correlations between dental pulp cell count of odontoblasts, subodontoblasts and fibroblasts and age, within different age groups. Formulation of regression equations using the dental pulp cell count for predicting age was attempted. DESIGN: Eighty-one extracted teeth were grouped into two age groups (6-25 years, 26-80 years). The teeth were demineralized and histological sections were prepared for cell count. Regression equations were generated from regression analysis of cell count and tested for age estimation. RESULTS: The number of dental pulp cells were found to increase until around the third decade of life and following this, the odontoblasts and subodontoblasts cell numbers began to decline while the fibroblasts seemed to remain almost stationary. The Pearson correlation test revealed a significant positive correlation between the cell number for all type of cells and age in the 6-25 years group (r=+0.791 for odontoblasts, r=+0.600 for subodontoblasts and r=+0.680 for fibroblasts). In the 26-80 years age group, a significant negative correlation of the odontoblasts (r=-0.777) and subodontoblasts (r=-0.715) with age was observed but for fibroblasts, the correlation value was negligible (r=-0.165). Regression equations generated using odontoblasts and subodontoblasts cell number were applicable for age estimation. The standard error of estimates (SEEs) were around±5years for 6-25 years and±8years for 26-80 years age groups. The mean values of the estimated and chronological ages were not significantly different. CONCLUSIONS: A significant correlation between the cell count of odontoblasts and subodontoblasts with age was demonstrated. Regression equations using odontoblasts and subodontoblasts cell number can be used to predict age with some limitations.