# Estimation of Age in Humans Using Dental Translucency of Permanent Teeh: An Experimental Study
## 4 Discussion
As a result of this, we found a more precise and accurate age estimation in individuals aged < 40 years and an underestimation of age in older people according to a pattern observable from age 40 and beyond consistently with the literature [11; 17; 31]. Unlike the age factor, sex does not seem to influence the age estimate obtained with RTD significantly. This result generally finds confirmation in other previous studies (among others: [10; 14; 31]). Other studies previously developed and applied regression equations to estimate age from dental translucency in different populations (as detailed in Table 1). Because none of these equations has been developed specifically for the Italian population, we checked the reliability of the estimates obtained by applying these formulas to our sample. The results obtained applying these literature equations on the overall Italian sample indicated a better performance with the equations developed by [PERSON] and [PERSON] [19] and [PERSON] et al. [11] regardless of population (in the first case, they were Norwegians and in the second Indians) or tooth type (in the first case any type, in the second lower central incisors). Although it is generally believed that biological profiles should be drawn taking into account the population of origin, the results obtained seem to indicate a reduced influence of population affinity on RDT, as also noted by [PERSON] [32] in contrast to [PERSON] et al. [17]. On the other hand, [PERSON] and [PERSON] [8] recognized that ancestry is not a significant factor but suggested considering both ancestry and sex to reduce the mean error. As for tooth type, the use of only single-rooted teeth for RDT purposes is prevalent in the literature, with a few exceptions (among those applied: [19; 21]). Confirming previous research [18], our study had the merit of showing that multi-rooted teeth can be used for age estimation, performing even better than mono-rooted teeth. This finding will have an important implication in forensics since age estimation can be conducted anyway, whatever type of tooth is available. In this study, we developed a new formula to estimate the age of unidentified individuals based on RTD. In particular, this regression equation employs only one variable, as RHT was found to be the most significant age predictor of the three indicators considered. Moreover, PH had lower reliability and reproducibility in comparison to RHT. An analogous choice was made by [PERSON] and [PERSON] [19] and [PERSON] et al. [21]. The new equation applied to the holdout sample resulted in a better age estimate than that obtained from the formulas of [PERSON] and [PERSON] [19] and [PERSON] et al. [11]. This new equation, therefore, can be considered a relevant addition to the estimation of adult age-at-death in forensics, but its application should be supported by the use of other skeletal indicators of age. Moreover, further studies are needed to validate our new formula on other population samples. Strengths of this study include the application of a dental method of age estimation that does not require specific and costly laboratory instruments. In addition, we used different types of teeth (mono and multi-rooted), proving the applicability of RDT. Being concerned with forensically unknown human remains, one appreciable element of RHT is that it appears to be little influenced by sex and population affinity. Unlike several other studies that have examined RTD in osteological collections -the remains' antiquity and the postmortem environment would affect the RTD according to [PERSON] et al. [33], we examined a current population sample with known age and sex, thus providing results that can be applied with greater confidence in the forensic field on contemporary human remains. The main limitations of this study relate to the use of extracted teeth for therapeutic purposes. However, according to findings from previous studies [15; 34], periodontal disease does not necessarily affect translucency.