# Evaluation of the Distal Periodontal Bone Defect Associated with Lower Third Molar Extraction
## 3 Results  
A total of 109 third molars were extracted at the University Dental Clinic of the Politclinic of Modena between 1 January 2019 and 31 December 2020. Of these, 56 third molars were excluded for not meeting the inclusion criteria. Specifically, 3 patients were pregnant, 14 patients lacked retrievable pre-operative panoramic radiographs, and 39 patients were unavailable for follow-up examination and questionnaire completion. The final analysis included 29 patients (18 females, 62.1), accounting for 53 lower third molars. Female participants were more prevalent in the Mesial-Inclined and Vertical groups, whereas the Horizontal group had a higher proportion of male participants. Participants' ages ranged from 18 to 49 years, with an average age at the time of extraction of 25.1 \(\pm\) 5.8 years. The mean age was similar across groups. Smoking habits showed no statistically significant impact on outcomes, with 14 participants (48.3%) identified as smokers. No significant differences in periodontal probing depth (PPD) levels were observed between smokers and non-smokers (Table 1). The third molars were classified by inclination: 22 (41.5%) as mesioangular, 10 (18.9%) as horizontal, and 21 (39.6%) as vertical (Table 2). Analysis of PPD and clinical attachment level (CAL) values aimed to evaluate the influence of tooth inclination on post-operative healing. The position in the tooth in the dental arch (right or left) did not significantly affect the outcomes (Table 2) \begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & **Total (_n = 29_)** & **Mesioangular (\(n\) = 22, 41.5\%)** & **Horizontal (\(n\) = 10, 18.9\%)** & **Vertical (\(n\) = 21, 39.6\%)** & **\(p\)-Value** \\ \hline Gender & & & & \\ Female & 18 (62.1) & 9 (75.0) & 2 (33.3) & 7 (63.6) & 0.227 \\ Male & 11 (37.9) & 3 (25.0) & 4 (66.7) & 4 (36.4) & \\ \hline Smoking & 14 (48.3) & 5 (41.7) & 4 (66.7) & 5 (45.5) & 0.589 \\ \hline Age, Mean \(\pm\) SD & 25.9 \(\pm\) 6.6 & 27.0 \(\pm\) 9.1 & 25.1 \(\pm\) 3.5 & 25.4 \(\pm\) 5.0 & 0.812 \\ (range) & (18.0–49.2) & (18.2–49.2) & (21.1–29.7) & (18.2–34.2) & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Demographic characteristics of included patients and angular position of teeth. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & **Total (_n = 53_)** & **Mesioangular (\(n\) = 22, 41.5\%)** & **Horizontal (\(n\) = 10, 18.9\%)** & **Vertical (\(n\) = 21, 39.6\%)** & \\ \hline Teeth & & & & \\
38 & 28 (52.8) & 12 (54.5) & 6 (60.0) & 10 (47.6) & 0.794 \\
48 & 25 (47.2) & 10 (45.5) & 4 (40.0) & 11 (52.4) & \\ \hline P and G & & & & \\ A & 20 (37.7) & 1 (4.5) & 3 (30.0) & 16 (76.2) & \(<\)0.001 \\ B & 24 (45.3) & 15 (68.2) & 4 (40.0) & 5 (23.8) & \\ C & 7 (13.2) & 4 (Pell and Gregory classification (P and G): Group A included a higher proportion of mesioangular third molars, while Group B was more common in the Horizontal group. Group C was exclusive to the Mesial-Inclined group. An association was observed between the Pell and Gregory classification and inclination, with mesioangular and horizontal teeth predominantly in Classes B and C, indicating greater impaction depth. Most cases were classified as Level II, suggesting that the tooth was unable to fully erupt into the arch (Table 2). Pre-operative panoramic radiographs revealed significantly higher distal bone peak (POD) values in mesioangular (5.3 \(\pm\) 2.1 mm) and horizontal (6.4 \(\pm\) 1.9 mm) third molars compared to vertical molars (2.5 \(\pm\) 1.4 mm). However, mesial bone measurements adjacent to the second molar did not significantly influence post-operative outcomes. Post-operative residual distal bone peaks (POD) were highest in the Horizontal group (2.3 \(\pm\) 0.8 mm), followed by Mesioangular (1.9 \(\pm\) 1.2 mm) and Vertical (1.4 \(\pm\) 0.5 mm) groups, though these differences were not statistically significant. Similarly, residual probing depth tended to be greater in the Horizontal group, although differences between groups were not statistically significant.