## 4 Discussion
Nevertheless, it was not possible to carry out an analysis on the surgeries that did not require odontomy or osteotomy as it was not explicitly reported in the published studies. Considering all types of antibiotics and all methods of administration in case of osteotomy, 11 studies were considered in a total of 1763 surgeries performed (see Figure S11, Supplementary material). In this case, the RR, significantly in favor of prophylaxis, was 0.54 with the fixed model and 0.50 with the random model. Furthermore, the heterogeneity of the data was found scarce and insignificant (28%, \(p>0.10\)) and the number of patients to be treated to obtain a therapeutic benefit was equal to 19. Therefore, it is possible to state that from the analysis of the literature the results homogeneously indicate a favorable effect of the administration of prophylactic antibiotics in case of osteotomy. The meta-analysis of the data regarding pre-surgical prophylaxis with all types of antibiotics in case of osteotomy, included 5 studies for a total of 306 surgeries performed (see Figure S12, Supplementary material). In this case, the RR, significantly in favor of prophylaxis, was 0.27 both with the fixed and random models. Furthermore, the heterogeneity of the data was found to be zero and the number of patients to be treated to obtain a therapeutic benefit was equal to 6. Therefore, it can be stated that the literature homogeneously indicates a favorable effect in favor of administration of pre-surgical prophylactic antibiotics in case of osteotomy. The effectiveness of the pre-surgical administration of penicillin antibiotics in case of osteotomy was evaluated based on 3 studies, for a total of 183 surgeries (see Figure S13, Supplementary material). This prophylaxis modality did not demonstrate a significant benefit, with moderate but significant heterogeneity (44%, \(p>0.10\)), and an NNT equal to 10. Therefore, it can be stated that from literature analysis, no advantages emerged for the pre-surgical prophylaxis with amoxicillin in the case of osteotomy. The meta-analysis of the data regarding pre-surgical prophylaxis with non-penicillin antibiotics in case of osteotomy included 2 studies for a total of 123 surgeries (see Figure S14, Supplementary material). The RR was significantly in favor of prophylaxis with both the fixed and random models, with an identical value (0.22). Furthermore, the heterogeneity of the studies was zero and the NNT was equal to 4. Therefore, it can be stated that from the analysis of the literature, the results homogeneously indicate a favorable effect in favor of pre-surgical administration of non-penicillin antibiotics in case of osteotomy. Overall, in the case of osteotomy, the pre-surgical administration of antibiotics for the prophylaxis of surgical site infections following the extraction of the mandibular third molar has a significant efficacy. However, this result is not homogeneous in the scientific literature because of the presence of studies that consider the use of amoxicillin, which also has not proved useful in the prevention of postoperative infections of the surgical site in case of osteotomy. Instead, data in literature unanimously indicate a significant and clinically important efficacy for pre-surgical prophylaxis with non-penicillin antibiotics in case of osteotomy. The meta-analysis of the data regarding pre- and post-surgical prophylaxis with all types of antibiotics in case of osteotomy, included 7 studies for a total of 940 surgeries(see Figure S15, Supplementary material). In this case, the RR significantly in favor of administering prophylaxis, was 0.56 both with the fixed and random models. Furthermore, the heterogeneity of the data was found to be zero and the NNT was equal to 28. Therefore, it can be stated that the literature homogeneously indicates a favorable effect in favor of pre- and post-surgical prophylactic antibiotics in case of osteotomy.