Assessment of the mandibular incisive and mental canal in dentate and edentulous mandibles using cone-beam computed tomography.

Objectives: This study evaluated the prevalence, diameter and location of the mandibular incisive canal (MIC) and the transition pattern and anterior loop length (ALL) of the mental canal and compared these values between dentate and edentulous mandibles. Methods: A total of 187 cone-beam computed tomography (CBCT) images of mandibles, namely, 100 images of dentate mandibles and 87 images of edentulous mandibles, were obtained. CBCT data related to the incisive canal and mental canal were analyzed by one examiner. Results: The prevalence of the MIC was 75∼78 %, showing no difference based on laterality or the presence of teeth. The ALL significantly differed depending on the presence of teeth as well as sex. The presence of teeth affected the size of the MIC in the female group, and the diameter of the MIC in the edentulous group was significantly narrower than that in the dentate group. The diameter of the MIC was significantly greater in males than in females in the edentulous group. Meanwhile, the location of the MIC in the male group depended on the presence of teeth at each measuring point, and the MIC was significantly closer to the lower border of the mandible in the female group than in the male group at all measuring points except at 0 mm. Conclusions: This study indicated that the presence of teeth significantly affects the type of transition of the mental canal, the ALL, and the diameter and location of the MIC. Additionally, sex could be a factor affecting MIC location, MIC diameter and anterior loop length.

Identification of anterior loop in different populations to avoid nerve injury during surgical procedures-a systematic review and meta-analysis.

Exact recognition of the anterior loop is very important to avert any injury to the neurovascular bundle during surgical procedures. The purpose of this review was to evaluate the prevalence and length of the anterior loop in different populations. A comprehensive search of Medline/Pubmed and Cochrane database was done. The focused question was the presence of anterior loop (including loop length) of the inferior alveolar nerve in mental foramen region in CBCT images of the various subjects. Articles related to the presence of anterior loop (including loop length) were only included. Initial literature search resulted in 3024 papers, after removing duplicate articles, 2821 articles were left. Two thousand seven hundred eighty-four articles were further excluded by the reviewers after screening the abstracts which resulted in 37 studies. Hand searching resulted in 2 additional papers. Seven full-text articles were excluded for not fulfilling the inclusion criteria. Finally, 32 articles were included in the review. Two thousand five hundred three subjects with anterior loop were found, which approximates 38% with 48.4% bilateral, 27.8% right side, and 23.8% left side. The loop distribution in males and females was also found to be different. There was highly significant (P < 0.001; I2 = 98.81%) heterogeneity found in the included studies. Variations were found in the prevalence, length, gender, and side distribution of anterior loop in various populations. This systematic review highly recommends not relying on any average values and the clinician should compulsorily make use of imaging modalities available in each and every case, wherever surgical procedure is to be performed near mental foramen region.

Location of the Mandibular Incisive Canal Related to the Placement of Dental Implants: A Case Report.

Cone-beam computerized tomography (CBCT) can show an uncommon mandibular incisive canal that cannot be detected by panoramic radiography, which is used preoperatively to form the initial plan of the size and length of an implant fixture for surgical placement in the mandibular interforaminal area. Determination of the position and anatomical configuration of the mandibular incisive canal is challenging. The purpose of this case report is to discuss anatomical variations in the mandibular incisive canal and the mental canal by reviewing previous studies. Furthermore, we propose that the anterior loop length of the mental canal near the mental foramen, as well as the diameter of the mandibular incisive canal, should be verified by CBCT prior to performing implant surgery in the anterior mandibular area to prevent possible nerve damage.

Assessment of the Anterior Loop of the Mental Nerve Using Cone Beam Computerized Tomography Scan.

The purpose of this study is to use cone-beam computerized tomography (CBCT) scans with oblique-transverse reconstruction modality to measure and compare the anterior loop length (AnLL) of the mental nerve between gender and age groups and to compare the difference between the right and left sides. Sixty-one female and 61 male CBCT scans were randomly selected for each age group: 21-40, 41-60, and 61-80 years. Both right- and left-side AnLLs were measured in each subject using i-CATVision software to measure AnLLs on the oblique transverse plane using multiplanar reconstruction. The anterior loop was identified in 85.2% of cases, with the mean AnLL of the 366 subjects (732 hemimandibles) being 1.46 ± 1.25 mm with no statistically significant difference between right and left sides or between different gender groups. However, the mean AnLL in the 21-40 year group (1.89 ± 1.35 mm) was larger than the AnLL in the 41-60 year group (1.35 ± 1.19 mm) and the 61-80 year group (1.13 ± 1.08 mm). In conclusion, when placing implants in close proximity to mental foramina, caution is recommended to avoid injury to the inferior alveolar nerve. No fixed distance anteriorly from the mental foramen should be considered safe. Using CBCT scans with the oblique-transverse method to accurately identify and measure the AnLL is of utmost importance in avoiding and protecting its integrity.