Aspectos anatômicos de reparos da região interforaminal mandibular e suas correlações clínico-cirúrgicas: estudos com tomografia computadorizada de feixe cônico e revisões sistemáticas da literatura

Abstract

Mental foramen (MF), anterior loop (AL), accessory mental foramen (AMF), lingual foramina (LF), and genial tubercles (GT) are important mandibular anatomical structures that must be thoroughly evaluated by cone beam computed tomography (CBCT) when planning of surgical interventions. In this context, the present thesis presents five chapters that have as main objectives, respectively: 1) to carry out systematic reviews (SRs) on studies that evaluated fractures of the GTs (chapter 1), LF (chapter 2), and the MF and AL (chapter 3) through CBCT; 2) describe topographic aspects of TG in CBCTs and propose an imaging classification for this (chapter 4); 3) describe topographic aspects of the FM, FMA and FL using CBCT and assess the estimated risk concerning surgical procedures in the anterior mandibular region (Chapter 5). In chapters 1, 2 and 3 SRs were carried out in different databases, registered on the PROSPERO platform, and followed the items in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guide. In chapters 4 and 5, cross-sectional studies with CBCT were carried out. Radiomorphometric aspects (absolute/relative linear, vertical/horizontal, and angular) mandibular measurements (MF, AMF, LF, and GT) were observed, as well as demographic information. In the five chapters, descriptive analyzes and appropriate statistical tests were performed, considering a value of p<0.05 as significant. In the SR chapters, there was statistically significant heterogeneity between the studies. The overall prevalence of up to 2 LF was 88.54%, with some studies having four FL (0.59%). The SR on GT fractures found 24 cases reported in the literature, mainly isolated and associated with edentulism, commonly diagnosed by clinical examination and computed tomography. In relation to MF and AL, the most frequent anatomical location of the MF was between the lower premolars or closer to the second premolar. Some studies have reported a greater vertical diameter of the MF in men compared to women. The prevalence of AL ranged from 2.47% to 94%, and its average length ranged from 0.89mm to 3.69mm. In chapter 5, there was a prevalence of 89.86% (n= 300) of at least one TG, the majority being double (57%). A new tomographic classification has been proposed for TGs, the most frequent being type IIIA (38.7%), followed by IIIB (36.6%), IIA (21.4%), and IIB (3.6%). In chapter 5, the present study observed a 7.2% prevalence of AMF (women, 5.2%; men, 2%). The anterior LA was observed in 45.8% of the CT scans, with no difference between the sides, and the FL was present in 94.4% of the cases, with 31% of the individuals having two FL. The surgical risk estimate in the anterior region showed a distance of 4mm anterior to the FM, a depth of 4mm for graft harvesting, and osteotomies for genioplasty with a distance of at least 5mm to the FM as relatively safe references for invasive procedures in this area.