# 2D vs. 3D Radiological Methods for Dental Age Determination around 18 Years: A Systematic Review
## 3 Results  
The article selection process is illustrated through the PRISMA flow diagram presented in the Figure 1.  
The electronic databases search yielded 1455 articles. After overlapping data among the databases identification and duplicates removal, 938 papers were screened. After titles and abstracts screening, 108 articles were selected for full-article review. A total of 43 articles met the inclusion criteria and, after application of exclusion criteria, 25 were selected for analysis. Ten articles compared CBCT vs. OPG in dental anatomy evaluation, five articles evaluated the accuracy of dental methods for age estimation, both with CT and OPG exams, and the remining 10 compared CBCT vs. OPG in terms of radiation dose. CBCT was found to be more accurate than OPG in dental anatomy evaluation, because of the absence of distortion and superimpositions of different structures. Several dental methods were used  
Figure 1: PRISMA flow diagram of literature search. for age evaluation, each one with a different degree of reliability depending also on the age to be evaluated. When analyzing young adults, an estimation error of two years is considered forensically acceptable. The radiologic dose of a CBCT exam is higher compared to an OPG exam; with small Field Of View (FOV) and low-resolution protocols, the difference is not so marked. Data extracted from more significant manuscripts are summarized in Tables 4-6 [6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28]. A simplified version of the NIH (National Institutes of Health) Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies [29] was adopted to evaluate the risk of bias and the methodological quality of the included papers, because they presented the results of cross-sectional studies. When it was not possible to evaluate one of the questionnaire items due to lack of information \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Author** & **Anatomical Structure** & **Age Interval** & \multicolumn{2}{c}{**Radiographic Method**} \\ \hline [PERSON] et al. (2018) & Mandible and maxilla & child & Effective dose: CBCT 1272 \(\mu\)Sv—OPG 20 \(\mu\)Sv \\ [PERSON] et al. (2018) & Anterior maxilla & child & Effective dose: CBCT 88 \(\mu\)Sv—OPG 4.1 \(\mu\)Sv \\ [PERSON] et al. (2017) & Maxillofacial complex & adult & Thyroid exposure: CBCT 0.85 \(\pm\) 0.55 mGy \\  & & & &
\begin{tabular}{c} OPG \(0.06\pm 0.04\) mGy \\ \end{tabular} \\ [PERSON] et al. (2016) & Maxillofacial complex & adult & Thyroid effective dose: \\  & & & CBCT 388.5 \(\mu\)Sv—OPG 34.5 \(\mu\)Sv \\ [PERSON] et al. (2016) & Mandible and maxilla & adult & Thyroid effective dose: \\  & & & CBCT 9.32 \(\mu\)Sv—OPG 15.8 \(\mu\)Sv \\ [PERSON] et al. (2014) & Frontal teeth & adult & DAP: CBCT 279 mGy cm\({}^{2}\) OPG 252 mGy cm\({}^{2}\) \\ [PERSON] et al. (2013) & Alveolar ridge & 58–94 & Effective dose: CBCT 10 \(\mu\)Sv—OPG 10 \(\mu\)Sv \\ [PERSON] et al. (2013) & Frontal teeth & - & Effective dose: CBCT 11.3 \(\mu\)Sv—OPG 17.8 \(\mu\)Sv \\ [PERSON] et al. (2010) & Mandible and maxilla & adult & PKA: CBCT 350 mGy cm\({}^{2}\) OPG 80 mGy cm\({}^{2}\) \\ [PERSON] et al. (2008) & Mandible and maxilla & - & Thyroid effective dose: \\  & & & CBCT 124.3 \(\mu\)Sv—OPG 13.1 \(\mu\)Sv \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Summary of data regarding radiation dose evaluation.