# Age Assessment through Third Molar Teeth Developmental Stage in Children
## 3 Results  
A total of 324 panorex had been analyzed in the study. Of note, not all panorex had all third molars evident in the X-ray. There were 179 males and 145 females. The \(t\)-test comparing the developmental stage differences between the right and left side, in the maxilla and mandible separately, found no statistical difference for the right and left sides, both on upper teeth (\(p\) = 0.656) and on the lower teeth (\(p\) = 0.873). Therefore, for further statistics, only one tooth (using the developmental stage of the tooth) was used for further statistics on each jaw. Most cases demonstrated equal stages on the right and left sides. However, when there was inconsistency between the right and left sides, the higher developmental stage was used as the developmental stage for the analysis. Table 1 presents the mean age (and standard deviation) in the different groups of the third molar developmental stage. Since there were only a few cases of teeth development stages 7 and 8, they were merged into a single group. A Pearson correlation was conducted to analyze the correlation between the third molar developmental stage (Demirjian stage) and the chronologic age of the patient, based on the date of birth. A high correlation was found between third molars and the chronological age, both in the maxilla and in the mandible (Pearson correlation of 0.767, 0.793 for maxillary and mandibular teeth, respectively, \(p\) < 0.0001)  
On one-way ANOVA, statistical significance was found between the different developmental stages for each jaw (\(p\) < 0.001). [PERSON]'s HSD test for multiple comparisons found that the mean value of the developmental stage was significantly different between stages 6 and 7; stage 5; and stages 2, 3, and 4 in the maxilla and between stages 6 and 7, stage 5, stage 4, and stages 2 and 3 in the mandible. In order to characterize the possible differences between males and females, a two-way ANOVA was executed. Statistical significance was found for the developmental stage (\(p\) < 0.0001) with no statistical significance for gender (\(p\) = 0.409 for the maxilla and \(p\) = 0.368 for the mandible). The only difference was seen in stage 1: girls reach stage 1 at an earlier age (around 10 years in girls, and 11-12 years in boys). Figure 2 shows the marginal means for males and females in the maxilla and mandible, according to tooth developmental stage. The correlation between the chronological age and tooth developmental stage was analyzed, classifying the chronological age into three different categories: age higher and lower than 12 years, age higher and lower than 14 years, and age higher and lower than 16 years. A Chi-square analysis was conducted, with statistical significance (\(p\) < 0.0001) for all three categories. Patients in developmental stage > 5 were older than 12 years in 100% of cases in the maxilla and in 97% of cases in the mandible. Patients in developmental stage > 6 were older than 14 years in 100% of cases both in the maxilla and the mandible. Patients in developmental stage > 7 were older than 16 years in 100% of cases both in the maxilla and the mandible. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Developmental**} & \multicolumn{2}{c}{**Maxillary 3 rd Molar**} & \multicolumn{2}{c}{**Mandibular 3 rd Molar**} \\ \cline{2-5}  & \(N\) & **Mean \(\pm\) SD** & \(N\) & **Mean \(\pm\) SD** \\ \hline
1 (a) & 4 & 11.32 \(\pm\) 1.68 & 19 & 10.35 \(\pm\) 1.27 \\
2 (b) & 56 & 10.90 \(\pm\) 1.37 & 61 & 11.05 \(\pm\) 1.35 \\
3 (c) & 65 & 11.65 \(\pm\) 0.98 & 78 & 11.76 \(\pm\) 0.98 \\
4 (d) & 121 & 12.65 \(\pm\) 1.11 & 96 & 12.90 \(\pm\) 1.13 \\
5 (e) & 29 & 14.92 \(\pm\) 1.29 & 33 & 14.77 \(\pm\) 1.48 \\
6 (f) & 12 & 17.13 \(\pm\) 1.38 & 9 & 17.49 \(\pm\) 1.53 \\
7 (g \& h) & 9 & 18.28 \(\pm\) 1.36 & 9 & 18.23 \(\pm\) 1.38 \\ \hline Total & 296 & 12.66 \(\pm\) 2.12 & 305 & 12.57 \(\pm\) 2.14 \\ \hline \hline \end{tabular}
\end{table}