Applicability of the Nolla Classification Scheme within the KwaZulu-Natal population of South Africa

Background: Dental age estimation is important in clinical practice for orthodontic treatment, forensic sciences and radiology. The Nolla (1960) classification scheme is one of the most frequently utilized estimation tools in teaching and clinical practice. However, the applicability of the Nolla (1960) classification scheme in determining age in a select KwaZulu-Natal population of South Africa is unknown. Therefore, this study aimed to determine the applicability of the Nolla Classification Scheme on a select South African sample of KwaZulu-Natal and develop a regression model to extend the Nolla (1960) maturation and age norm tables beyond 17 years. Materials and methods: 840 digital panoramic radiographs of individuals aged between 5 and 25 years met the inclusion criteria. The 8 maxillary and 8 mandibular teeth in the left quadrant was analysed using the Nolla (1960) Classification Scheme. The paired T-test, Wilcoxon and Polynomial Regression Analysis were performed. Results: The original Nolla (1960) method over-estimated age for the entire sample in this study by −0.39 and −0.57 years in females and males, respectively. While, the modified Nolla (1960), highlighted an overall under-estimation in females, but over-estimation in males aged between 18.00 and 18.99 years. Conclusion: The Nolla Classification scheme over- or under-estimated dental age with the select population group, therefore population-specific tables were developed for the South African Black and Indian population groups of KwaZulu-Natal. This may increase the accuracy of age estimation of the selected South African sample within the KwaZulu-Natal region.