Available bone morphology and status of neural structures in the mandibular interforaminal region: three-dimensional analysis of anatomical structures

Morphometric Analysis of the Midline Mandibular Lingual Canal and Mandibular Lingual Foramina: A Cone Beam Computed Tomography (CBCT) Evaluation

BACKGROUND

This study aimed to evaluate the midline mandibular lingual canals and foramina and their anatomic variations using CBCT scans.

METHODS

This study used retrospective analysis. A total of 320 CBCT scans were used to evaluate the study parameters, which comprised the presence or absence of the mandibular lingual foramen (MLF)/mandibular lingual canal (MLC) and its category, the distance between the buccal cortex and the start of the MLC, the distance between the inferior border of the mandible and the superior border of the foramen at its lingual and buccal terminals. The length and diameter of each canal at its lingual and buccal terminals.

RESULTS

MLC was found in all included CBCT scans. Out of 320 included CBCT scans, a single canal was represented by 30.9%, double canals (Supra with Infra -spinosum) configuration appeared in 54.7%, and triple canals (Supra-Inter-Infra) represented 14.7%. The supraspinosum canals averaged 5.81 ± 2.08 mm in length and 0.87 ± 0.30 mm in diameter at the lingual terminal. In terms of the number of canals, there was a significant difference between men and women (p ≤ 0.001), with 60% of the men in the sample having double canals and 43.1% of the women having single canals. Moreover, the male gender had a higher prevalence of triple canals (21.3% vs. 8.1%) than females. Males and females were distributed equally among the supraspinosum canals, with no statistically significant difference (p ≤ 0.7). A considerable increase in the finding of interspinosum and infraspinosum canals was seen in the male sample (p ≤ 0.001).

CONCLUSIONS

midline mandibular canals were found in all investigated CBCTs of the sample of both sexes; however, the anatomy and location of the MLF and canals varied significantly among the Saudi population.

Determination of Morphogeometric Patterns in Individuals with Total Mandibular Edentulism in the Interforaminal Region from Cone Beam Computed Tomography (CBCT) Scans: A Pilot Study

The aim of this study was to determine the morphogeometric patterns of the interforaminal region from cone beam computed tomography (CBCT) scans of individuals with total mandibular edentulism. CBCT images were obtained from 40 patients with total edentulism who are older (12 men and 28 women; average age of 69.5 ± 9.4 years) and who wore a non-implant-supported, lower, removable, total prosthesis. We conducted a two-dimensional (2D) morphogeometric analysis of the Digital Imaging and Communication in Medicine (DICOM) files from the CBCT scans, and five equidistant cross sections were planned. For the three-dimensional (3D) morphogeometric analysis, standard triangular language (STL) files were obtained after segmentation of the interforaminal mandibular region, and four anatomical landmarks and their respective curves were digitized. The patterns among the shapes were determined using principal component analysis (PCA) on MorphoJ software (version 1.07a). The results of the 2D morphogeometric analyses for PCA of the interforaminal mandibular paramedian region were PC1 or elongated drop shape, 54.78%; PC2 or wineskin shape, 17.65%; PC3 or pear shape, 11.77%; and PC4 or eggplant shape, 5.71%, and those for PCA of the symphyseal region were PC1 or elongated drop shape, 62.13%; PC2 or ovoid shape, 11.64%; PC3 or triangular shape, 9.71%; and PC4 or tuber shape, 4.96%. The results of the 3D morphogeometric analyses for the interforaminal hemimandibular region were PC1, 59.83%; PC2, 10.39%; PC3, 7.67%; and PC4, 5.09%. This study provides relevant information for future clinical guidelines on prosthetics and implants, in addition to proposing the use of new technologies that support diagnosis and treatment in patients with edentulism.

Prevalence and extension of the anterior loop of the mental nerve in different populations and CBCT imaging settings: A systematic review and meta-analysis

Purpose

Materials and Methods

Results

Conclusion

Systematic review and meta-analysis of lingual foramina anatomy and surgical-related aspects on cone-beam computed tomography: a PROSPERO-registered study

PURPOSE

This study aimed to summarize the evidence regarding lingual foramen (LF) characteristics using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

A registered systematic review (#42,019,145,962) was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statements. An electronic search without date or language restrictions was performed in five databases, including grey literature (Google Scholar and ProQuest). The Meta-Analysis of Statistics Assessment and Review Instrument was used to evaluate the selected studies.

RESULTS

A total of 6641 articles were identified, and 26 studies (8255 CBCT scans) were selected after a three-step selection process. There was a female predominance, and age ranged between 10 and 93 years. A total of 4336 LFs were observed among men (n = 2042) and women (n = 2294). Of this LF-related sample, 43.5% of the studies were from Asia, followed by Europe (33.5%), North America (14%), and South America (9%). Different distances from the LF to the alveolar crest (11.04-20.4 mm), buccal (4.73-4.91 mm), and lingual (8.75 mm) cortices and the inferior border of the mandible (8.48-26.59 mm) were evaluated.

CONCLUSION

In summary, this systematic review found that LF is an anatomical structure with a high prevalence among the included studies (greater than 90%), regardless of the population evaluated. The occurrence of at least one LF was the most common pattern.

Do Morphological Changes in the Anterior Mandibular Region Interfere with Standard Implant Placement? A Cone Beam Computed Tomographic Cross-Sectional Study

Objective

To determine the morphological features in the anterior mandibular region, the presence of lingual foramen and canal dimensions in Saudi subjects that would interfere with standard implant placement.

Methods

CBCT scans of patients seeking implant treatment were examined. Based on the dentition status, patients were categorized into edentulous (group I) and dentulous (group I). On the panoramic view, the distance between the two mental foramina was divided into vertical segments of 10 mm width. In each segment, vertical bone height and buccolingual thickness at three levels (alveolar crest, 5 mm, and 10 mm apical to the crest) were assessed. The lingual foramen prevalence and canal features were assessed as well. Comparisons between the two groups regarding the assessed parameters were performed using the t-test. The percentage of edentulous mandibles with thickness <6 mm corresponding to the standard implant diameter was also calculated.

Results

Following the inclusion and exclusion criteria, group I consisted of 45 subjects and group II comprised 26 subjects. Bone height and thickness at the crestal level were significantly less in edentulous (I) than dentate mandibles (II) (P < 0.0001). The lingual foramen was detected in 90% of patients. In both groups, males had significantly greater mandibular height than females (P=0.02 and 0.005). At the crestal level, the thickness was <6 mm in 50% of the anterior mandibular segments.

Conclusion

Half of the edentulous patients may receive normal size implants in the anterior interforaminal segments, while the other half will be limited to narrow implants (3.5 mm and less). The lingual foramen location, canal size, and position may represent another limitation for implant placement in that segment.

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.