Mandibular Canal Location: Cone-beam Computed Tomography Examination.

The increased use of implants and potential endodontic misadventures can lead to nerve damage. The purpose of this study was to use cone-beam computed tomography (CBCT) measurements to investigate mandibular canal (MC) location in relation to mandibular posterior teeth, the dimension of the buccal and lingual bone over the MC, the diameter of the MC, and the anterior loop location near the mental foramen. CBCT scans from 106 patients (age, 18-69 years) were used to evaluate measurements from 636 teeth and respective MC areas. Respective locations of MC to teeth (buccal, inferior, or lingual) were as follows: second molar (57% buccal, 40% inferior, and 3% lingual), first molar (18% buccal, 55% inferior, and 27% lingual), and second premolar (33% buccal, 55% inferior, and 11% lingual). Buccal bone thickness over the MC was thickest at mesial root of second molars and thinnest over the second premolar (5.4 versus 2.6 mm). The lingual bone next to the MC was thickest over the second premolar and thinnest at distal root of first molars (3.8 versus 1.7 mm). The average diameter of the MC along the length of the canal from second molar to second premolar was 3.03 mm on left and 2.91 mm on right. The anterior loop was present in 10.4% of patients, with the average depth below bone of 13.43 mm. The anterior loop was more often seen on the left side than right and occurred bilaterally 50% of the time. Mandibular bone thickness, nerve location, and dimension data all contribute to a useful knowledge base for practitioners. The application of CBCT imaging techniques aids in the surgical treatment, while offering advantages over conventional periapical and panoramic films.

Koivisto T ，Chiona D ，Milroy LL ，McClanahan SB ，Ahmad M ，Bowles WR ... -  《-》

Relationship between the anatomic structures and mandibular posterior teeth for endodontic surgery in a Turkish population: a cone-beam computed tomographic analysis.

Uğur Aydın Z ，Göller Bulut D 《-》

Anatomic Study of Mandibular Posterior Teeth Using Cone-beam Computed Tomography for Endodontic Surgery.

The present study aimed to anatomically assess mandibular posterior teeth using cone-beam computed tomographic (CBCT) imaging for endodontic surgery. A total of 170 CBCT scans were evaluated for anatomic variations of mandibular posterior teeth. All the scans were obtained using a Planmeca Promax CBCT unit (Planmeca, Helsinki, Finland) with exposure settings of 90 kVp, 12 mA, 12 seconds, and 0.3-mm resolution. All CBCT images were reconstructed by Romexis Viewer 3.8.2. software (Planmeca) on a 16-inch LCD monitor (22MP47HQ; LG, Seoul, South Korea), and axial, coronal and sagittal views were evaluated. The thickest buccal cortical plate was observed over the distal root of second molars (12.30 mm) among the molar teeth and over the second premolar root (5.41 mm) among the premolar teeth. The thinnest buccal cortical plate was observed over both the first and second premolar roots (0.42 mm) and over the mesial root of the first molar (0.62 mm) tooth. A 20.38-mm section was removed for surgical access during buccal resection of the distal root of the left second molar, and the closest distance from the apex to the inferior alveolar canal was 0 mm. Adequate knowledge of the anatomic dimensions of teeth and their surrounding structures is imperative for endodontic surgery. Information concerning the root thickness of mandibular posterior teeth at the site of root resection (apical 3 mm), buccal cortical plate thickness, and the distance from the apex of each tooth to the inferior alveolar canal and mental foramen can guide the surgeon before and during surgery.

Zahedi S ，Mostafavi M ，Lotfirikan N 《-》

A Limited Field Cone-beam Computed Tomography-based Evaluation of the Mental Foramen, Accessory Mental Foramina, Anterior Loop, Lateral Lingual Foramen, and Lateral Lingual Canal.

The aim of this retrospective observational study was to evaluate the cone-beam computed tomographic (CBCT)-based characteristics of the mental foramen (MF), accessory mental foramen (AMF), anterior loop (AL), lateral lingual foramen (LLF), lateral lingual canal (LLC) and to explore any relationships between their characteristics. The location and dimension of the MF; the incidence, location, and dimension of the AMF along with its distance to the MF; the presence and dimension of the AL; and the presence, location, angle of entry of the LLF and LLC, and its relation with the mandibular canal (MC) were evaluated in 109 CBCT scans. The data were analyzed descriptively, and associations were tested using the chi-square and analysis of variance tests. The MF was most frequently located between the first and second mandibular premolar teeth (43.5%) or below the second premolar (34.3%). The mean horizontal dimension of the MF was 3.1 mm, the vertical dimension was 2.8 mm, and the mean vertical distance from the alveolar crest was 14.2 mm. An AMF was observed in 12.8% of cases with a mean distance of 4.1 mm from the MF. An AL was present in 47.2% of cases with a mean loop length of 3.38 mm. An LLF was present in 20.4% of cases, predominantly below the first premolar (27.3%) with a mean angle of entry of 148°. The LLC always communicated with the MC and generally not with the tooth apex. A statistically significant association existed between the presence of the LLF and AMF. The anatomic complexity of the MF region was confirmed; hence, CBCT-based evaluation is essential before surgical exploration of this region.

Krishnan U ，Monsour P ，Thaha K ，Lalloo R ，Moule A ... -  《-》

Proximity of the Mandibular Canal to Teeth and Cortical Bone.

The proximity of the inferior alveolar canal to the mandibular molar roots may pose a risk of injury during various dental surgeries. The purpose of this study was to evaluate age-related and gender-related changes by using cone-beam computed tomography images between the roots of the second molars, mandibular cortex, and the inferior alveolar canal. One hundred fifty-five patients (68 men, 87 women), 20 years and older, who had previous cone-beam computed tomography scans were enrolled in this study. The patients were subcategorized by gender and age (group I, <21 years; group II, 21-40 years; and group III, >40 years). Distance between the mandibular canal (MC) and the second molar distal root apex as well as the 3 mandibular cortical regions (inferior cortex, buccal cortex, and lingual cortex) were measured. In men, the second molar root apex to the MC distance was significantly shorter in group I than in group III (P < .01). In women, the second molar root apex to the MC distance was significantly shorter in group I than in group II and group III (P < .05). In both men and women, the buccal cortex of the mandible to the MC distance was significantly shorter on the right side compared with the left side (P < .01). Our study shows that age, gender, and region have an influence on the location of the MC in the second molar area.

Kawashima Y ，Sakai O ，Shosho D ，Kaneda T ，Gohel A ... -  《-》