Age estimation of an Indian population by using the Kim's scoring system of occlusal tooth wear

Surface hardness and wear resistance of prefabricated and CAD-CAM milled artificial teeth: A cross-over clinical study

PURPOSE

To clinically evaluate the surface roughness and wear resistance of prefabricated and CAD-CAM milled acrylic resin teeth for complete dentures.

MATERIALS AND METHODS

In a cross-over study design, 10 completely edentulous patients were randomly included in this study and given two complete dentures. The first complete denture was made using prefabricated teeth, while the second was constructed using CAD-CAM milled teeth. Following insertion (T0), 3 months (T3), and 6 months (T6), the complete dentures were scanned. Utilizing 3D surface super-imposition techniques, the vertical (2D wear), and volumetric (3D wear) material loss were measured. The hardness of the teeth was evaluated at the time of denture insertion (T0) and then after 6 months (T6) of denture insertion by digital Vickers hardness tester. Statistical analysis was done using SPSS software. Paired groups were compared by paired t-test. Also, a repeated measure test was used. The significant difference was considered if p ≤ 0.05.

RESULTS

The time of denture function was linearly correlated with the wear of the prefabricated and CAD-CAM milled denture tooth. Prefabricated acrylic teeth had significantly more vertical and volumetric wear after 3 and 6 months, compared to CAD-CAM milled denture teeth where p-values were 0.01, 0.009, 0.003, and 0.024, respectively. Additionally, CAD-CAM milled teeth displayed significantly higher hardness values than prefabricated teeth both before and after 6 months of use where p-values were 0.001. After 6 months, all studied teeth showed a decrease in their hardness.

CONCLUSIONS

In terms of wear resistance and surface hardness, CAD-CAM milled acrylic resin teeth were superior to prefabricated acrylic resin artificial teeth once the complete denture functions.

Age- and sex-related changes in the position of the mental foramina and age estimation methods that use these changes

The position of the mental foramen is reported to change with age. This study aimed to examine age-related changes in the position of the mental foramen in men and women. Among 200 cases (age 21-100 years; 400 foramina) that underwent postmortem computed tomography, 109 (age 21-93 years; 218 foramina) with mandibular first and second premolars were examined using image analysis software to classify the position of the mental foramen according to Fishel's classification, and the χ² test was performed. The results showed that there was an association between age and the position of the mental foramen. The distance between the mental foramina was measured for 200 cases and a single regression analysis was conducted. The possibility that this method could be used to estimate the age of the cadavers was examined. The results of the single regression analysis showed a positive correlation (r = 0.54) of the distance with age in men and a negative correlation (r=-0.54) in women. The mean coefficient of determination for single regression analysis was 0.26 for both sexes, which was low, making it unsuitable as a stand-alone age estimation index, although it can aid in age estimation.

Estimation of Age by Evaluating the Occlusal Tooth Wear in Molars: A Study on Dakshina Kannada Population

Purpose

Assessment of teeth to estimate age in the living as well as the dead is well documented in the literature. Though applied in conjunction with other parameters in Gustafson’s technique, attrition of teeth solely is an underexplored indicator for age estimation mainly in India. Most of the studies using attrition of teeth have been conducted in bioarchaeology, and in populations where studies are being conducted in forensic contexts, the results are debatable. Thus, the present study aimed to evaluate the accuracy of age estimation using the Average Stage of Attrition (ASA) method by Li and Ji in adults of the Dakshina Kannada region.

Materials and Methods

This cross-sectional study assessed the degree of attrition in both maxillary and mandibular first and second molars of 136 adults of Dakshina Kannada origin (age range: 20–70 years) according to the 10 stages given by Li and Ji to derive population-specific linear regression equations.

Results

Univariate analysis of prediction of age with attrition showed a significant association of attrition score with age, stratified by sex, arch as well as in total (p-value <0.001) with a standard error of estimate of 9.231 years. The estimated age was within ±5 years of the actual age in 44.2% of the females and 50.0% of the males. A comparative review of 23 studies done to estimate age from attrition score clinically is documented in the manuscript.

Conclusion

The findings of this study suggest that evaluation of tooth wear by the Average Stage of Attrition (ASA) method can be used as a non-invasive means to aid in the determination of age in adults of Dakshina Kannada origin. Although the error increases with age, this method provides a measurable means of seriation into older and younger categories.

Tooth wear as an indicator of acculturation process in remote Amazonian populations

Riverine populations are typical of the Amazon region that depend on nature for subsistence. These people are considered an intermediate population between the urban and indigenous, the original Amazon habitants. The aim of this cross-sectional study was to evaluate the relationship between tooth wear and age in a remote riverine population from the Amazon, located by the Tucumanduba River (n = 94), and to compare them to previous findings obtained from semi-isolated indigenous (n = 223) and urban populations (n = 40) from the Amazon region, which were examined using the same methodology. Using linear regression, tooth wear explained 54.5% of the variation in the ages of the riverine subjects (p<0.001). This coefficient is mid-way between those obtained in semi-isolated indigenous populations (65–86%) and urban subjects (12%) living in the Amazon. Our findings suggest that tooth wear, a direct evidence of what an individual ate in the past, may be an indicator of the acculturation process in remote populations.

Validation of the efficacy of age assessment by the Brothwell tooth wear chart, using skulls of known age at death

Objective

The present study aims to validate the efficacy of age assessment by the Brothwell tooth wear chart, uniquely using skulls of recorded known age at death.

Materials and Methods

Fifty Chinese skulls, of known age recorded at death, ranging from 16 to 62 years, were used. All the skulls were anonymized laid out, numbered 1-50, and using randomized tables. A 70-mm, ×3 magnification glass with light (Rolson, Ruscombe, Twyford, Berkshire, United Kingdom) was used to evaluate tooth wear patterns, and the age assessed using newly devised "age calculator" based on the Brothwell Chart.

Results

The recorded age at death versus the estimated age derived from the Brothwell chart was statistically compared the weighted kappa score = 0.877, suggestive of a "very good" strength of agreement.

Conclusion

The Brothwell chart, based on tooth wear, can be used as a consistent method of age assessment, allowing for easier and more rapid data collection with no loss of overall accuracy.

Forensic Age Estimation of Chinese Malaysian Adults by Evaluating Occlusal Tooth Wear Using Modified Kim's Index

Background and Objective

Evaluation of dental attrition is an easy and relatively accurate approach to estimating the age of an adult either ante- or postmortem for some specific population. Dental attrition represents a progressive physiological age change that can be measured using variety of indices to aid as an adjunct in forensic age estimation. Some of the previously proposed indices have their own practical limitations. This paper focuses on using modified Kim's criteria to score dental attrition to estimate the age of Chinese Malaysian adults and validate it.

Methodology

Tooth wear was evaluated on 190 dental models of Chinese Malaysian adults (age range: 20–60 years) using modified Kim's index to custom-derive a population specific linear equation. The same equation was validated further on new 60 dental casts.

Results and Conclusion

Regression analysis revealed good correlation between age and teeth wear and lower standard error of estimate. Test of regression on a test sample (n = 30 pairs, age range: 20–60 years) showed insignificant difference between predicted versus the actual age with statistically acceptable mean absolute difference. These data suggest that modified Kim's index can be used effectively in forensic age estimation.

Restoration of the Occlusal Vertical Dimension with an Overlay Removable Partial Denture: A Clinical Report

The process of tooth loss throughout life associated with severe occlusal wear may pose a challenge in the rehabilitation of partially edentulous arches. In these cases, many therapeutic procedures are necessary because each tooth must be restored to obtain the correct anatomical contour and recover the occlusal vertical dimension (OVD). A removable partial denture (RPD) with occlusal/incisal coverage, also known as an overlay RPD, is an alternative treatment option with fewer interventions, and, consequently, lower cost. This clinical report reviews the principles involved in the clinical indication for an overlay RPD, as well as the necessary planning and execution, to discuss the feasibility and clinical effectiveness of this treatment, identifying the indications, advantages, and disadvantages of this procedure through the presentation of a clinical case. The overlay RPD can be an alternative treatment for special situations involving partially edentulous arches in patients who need reestablishment of the OVD and/or realignment of the occlusal plane, and it can be used as a temporary or definitive treatment. The main advantages of this type of treatment are its simplicity, reversibility, and relatively low cost; however, further studies are needed to ensure the efficacy of this treatment option.