An analysis of the first and second mandibular molar roots proximity to the inferior alveolar canal and cortical plates using cone beam computed tomography among the Saudi population

Radiological assessment of the inferior alveolar canal and mental foramen using cone beam computed tomography for pre-operative evaluation of surgeries in the mandible: A single-center five-year retrospective study

Introduction

Cone beam computed tomography (CBCT) plays a significant role in studying the anatomical structures of the mandible.

Aim

This retrospective study aimed to assess the role of CBCT at the pre-assessment stage of mandibular surgery.

Materials and methods

A total of 250 CBCT images were collected. The inferior alveolar canal (IAC) and mental foramen (MF) were measured bilaterally to the mandibular teeth apexes, including molars, premolars, and canines, to the buccal, lingual cortical bone, and to the inferior border of the mandible.

Results

There were no differences in the average number of extracted teeth between the right and left sides (P-value > 0.05, median = three teeth). It was noticed that the average measures of each point of the IAC and MF on the right side were closely matched to the similar point on the left side (P-value > 0.05). T-tests showed that there were differences between males and females on the M2 and M3 on the right side (P-value < 0.05) and on the M1, M2, and M3 on the left side (P-value < 0.05). Using one-way ANOVA tests, results showed that there were some differences in measures at P0 (F = 3.376, P-value = 0.003), P4 (F = 3.782, P-value = 0.001) on the right side, and at P3 (F = 5.620, P-value = 0.019) on the left side of the mandible.

Conclusions

There were no significant differences in IAC and MF positions between the right and left sides. However, between males and females, MF measurements showed significant differences on some points on the right and left sides. Although the history of extracted teeth showed no statistically significant difference in the location of IAC and MF, the number of extracted teeth showed an effect in the IAC position on the right and left sides, but not with the MF.

Cone-Beam Computed Tomography (CBCT)-Based Assessment of the Alveolar Bone Anatomy of the Maxillary and Mandibular Molars: Implication for Immediate Implant Placement

Purpose This study aims to examine specific aspects of socket morphology, including buccal and palatal/lingual bone width, interradicular bone (IRB) width, and assessments of root apices and furcation proximity to the vital structures of the maxillary and mandibular first and second molars using cone-beam computed tomography (CBCT). Materials and methods The study involved the analysis of 400 maxillary and mandibular first and second molars. Various measurements were taken to assess socket morphology, including mesiodistal (MD) and buccolingual (BL) width, buccal and lingual bone thickness at 2 mm apical to the alveolar crest, IRB width at 2 mm from the furcation, and the distance between the root apices and furcation to vital structures, such as the floor of the maxillary sinus (FMS) and inferior alveolar nerve (IAN). Results The mesiobuccal (MB) root of the second molar commonly intruded into the sinus, followed by the palatal root of the maxillary first molar. The mean FMS-F distance was 7.17 + 3.98 mm, and it was 7.2 + 2.72 mm for maxillary first and second molars, respectively. The mean IRB width was 2.77 + 0.96 and 2.29 + 0.74 mm for the first and second molars. The mandibular second molar had the shortest distance to the IAN in comparison to the first molar. For maxillary teeth, 7% of the first and 4% of the second molars presented alveolar anatomy adequate for immediate implant placement, compared to 84% and 50% of mandibular first and second molars. Conclusion Understanding the local alveolar bone anatomy of molars and its relationship to vital structures is crucial for the effective planning of implant treatments.

Buccolingual Inclination of Second Molars in Untreated Adolescents and Adults with Near Normal Occlusion: A CBCT Study

The mandibular second molars are lingually positioned relative to the alveolar ridge and have a limited amount of lingual alveolar bony support. As the maxillary second molars are articulated with the mandibular second molars, maintaining the normal buccolingual inclination of both maxillary and mandibular second molars would potentially help to not only optimize the masticatory function, but also avoid dehiscence and fenestration. The current study evaluated the buccolingual inclination of second molars in untreated adolescents and adults. One hundred and two Caucasian subjects with skeletal class I and minimum dental arch crowding/spacing were selected and divided into two groups: (1) adolescent group: age 12-18 years, N = 51 (21 females, 30 males); (2) adult group: age 19-65 years, N = 51 (40 females, 11 males). For each subject, the inclination for each second molar was measured as the angle between the long axis of each tooth and a vertical line on cone beam computed tomography images. The Mann-Whitney U test was used for intergroup comparisons. Maxillary second molars exhibited a buccal inclination of 15.30° in the adolescent group and 15.70° in the adult group. Mandibular second molars exhibited a lingual inclination of 17.05° in the adolescent group and 15.20° in the adult group. No statistically significant differences were detected between the age groups. In addition, a statistically significant difference was only found between genders in the adolescent group for the maxillary second molar inclination. In summary, maxillary second molars exhibited buccal inclination and mandibular second molars exhibited lingual inclination. The amount of buccolingual inclination of the second molars was similar in the adolescent and adult groups.

Assessment of the relationship of the distance between mandibular first and second molars with the inferior alveolar canal and cortical bone plate in an Egyptian subpopulation: a CBCT study

The aim of the current cone beam computed tomography (CBCT) study was to evaluate the proximity of mandibular first and second molar roots to the inferior alveolar canal (IAC) and mandibular cortex in an Egyptian subpopulation. Scans of 120 patients (480 molars, 960 roots) were obtained from the College of Dentistry database at the Suez Canal University, Egypt. Buccal and lingual bone plates and root thickness were measured at the specified resected root end 3 mm from the radiographic apex, and so was the proximity of the root apices to the IAC. Measurements of the right and left mandibular first and second molars were recorded for each root. Three examiners performed the measurements separately. ANOVA was used to compare the different roots. Bonferroni's post-hoc test was used for pair-wise comparisons when ANOVA was significant. The significance level was set at p ≤ 0.05. The findings displayed a closer proximity of the mandibular second molar apices to the IAC, as compared to the mandibular first molars. The mesial roots were at a shorter distance than the distal ones. Moreover, the mandibular second molars revealed the thickest total bone width including the root. So, it is beneficial for endodontists to be aware of the relation of the mandibular first and second molars to the surrounding cortical bone plates and the IAC before starting either nonsurgical or surgical endodontic treatment.

Data on alveolar mandibular bone thickness in Class I skeletal patient with bimaxillary protrusion

The alveolar bone thickness influences both diagnosis and limitation of tooth movement, therefore significance retraction was commonly applied in treating patients with bimaxillary protrusion. This is a retrospective data collection of pre and post treatment lateral cephalographs from 18 to 40 years old patient treated with four premolars extraction. The alveolar mandibular bone thickness was identified in sagittal planes with Image-J software based on cephalometry lateral radiographs. Statistical analysis namely Wilcoxon test and Pearson correlation analysis coefficient were used to understand the correlation of alveolar mandibular bone thickness variables and mandibular incisors position to skeletal profile treated with first premolars extraction are presented. This data is essential for advancing in a further understanding of Class I skeletal patients with bimaxillary protrusion.

Alveolar bone thickness overlying healthy maxillary and mandibular teeth: A systematic review and meta-analysis

OBJECTIVE

To systematically review and meta-analyse the Alveolar Bone Thickness (ABT) overlying healthy teeth. The secondary objective was to review the association of ABT with gender, age, and smoking.

MATERIALS AND METHODS

The PubMed, Embase, Scopus, ProQuest, Web of Science, and Cochrane Library databases were searched up to July 2020. English articles (sample size≥10) which had used CT or CBCT to measure the ABT at clearly defined reference points were included. The maximum likelihood approach meta-analysis was used to estimate the means (95% CIs).

RESULTS

A total of 68 articles were included. The meta-analysis results were as follows: In the anterior maxilla, the mean labial plate thickness ranged from 0.42-1.75mm, while it was thicker for the posterior teeth (0.78-4.31mm). The palatal plate thickness ranged from 0.97-8.13mm. In the anterior mandible, the thickness of labial and lingual plates ranged from 0.4-3.71mm and 0.38-5.44mm, respectively. The alveolar bone was thicker for the posterior teeth both at the labial (0.66-6.31mm) and lingual (2.31-7.77mm) sides. Meta-regression revealed a significant relationship between gender and ABT at several points. There was a controversy regarding the association of ABT with age. No significant difference was evidenced between smokers and non-smokers.

CONCLUSIONS

This study presents a clear image of the alveolar bone structure. Since it has pooled ABT values from various populations, outcomes could be acknowledged as global averages. Therefore, it could provide perspective for several dental procedures, including orthodontic treatments and immediate implant placement.

A CBCT Based Three-Dimensional Assessment of Mandibular Posterior Region for Evaluating the Possibility of Bypassing the Inferior Alveolar Nerve While Placing Dental Implants

A high rate of nerve injury and related consequences are seen during implant placement in the posterior mandibular arch. An approach has been proposed to avoid nerve injury by dodging the inferior alveolar nerve (IAN) while placing an implant. A prospective study with a total of 240 CBCT (cone beam computed tomography) images of patients with three dentate statuses, namely, edentulous (group I), partially edentulous (group II) and dentate (group III) were included in the study. The nerve path tracing was done on CBCT images with On-demand 3D software. The three dimensions, i.e., the linear distance from the outer buccal cortical plate to the inferior alveolar nerve (BCPN), linear distance from the outer lingual cortical plate to the inferior alveolar nerve (LCPN) and linear distance from the midpoint of the alveolar crest to the inferior alveolar nerve (ACN) were assessed. The data were presented and analyzed between variables using one-way ANOVA and independent t-test in SPSS version 21.LCPN of the right 1st premolar region (p < 0.05) was significantly different among the groups with edentulous subjects recorded with the minimum value (6.50 ± 1.20 mm). Females were found to have significantly (p < 0.05) less available bone (6.03 ± 1.46 mm) on the right side of the mandibular jaw compared to males in edentulous group of patients. On comparing age groups for partially edentulous subjects, LCPN of the right 1st premolar region had significantly (p < 0.05) less available bone (6.03 ± 0.38 mm) in subjects with age ≥54 years. The IAN follows a lingual course in the molar region and later flips to the buccal side in the premolar region. The LCPN dimension in the 1st and 2nd premolar region was found to be more than 6 mm irrespective of age, gender and side of the jaw. Thus, it can be considered as a suitable site for placing implants while bypassing the IAN with CBCT assessment remaining as the mainstay in the pre-surgical phase.

Biometric analysis of apical surgery-related anatomy of mandibular first molars: a cone-beam computed tomography study in a Mongoloid population

Objective

To evaluate the apical surgery-related anatomy of two-rooted and three-rooted mandibular first molars (MFMs) in a Mongoloid population.

Methods

A total of 502 cone-beam computed tomographic images were used to evaluate the root configuration, the distance from the buccal bone to each root, root dimensions, and the complete root resection distance at the resection level for roots of MFMs.

Results

The prevalence of two-rooted and three-rooted MFMs was 85.1% and 14.9%, respectively. At the resection level, the distance from the buccal bone to the mesial and distal roots of two-rooted MFMs was 2.24 and 3.15 mm, respectively, while the distance was 2.44, 2.01, and 8.55 mm for the mesial, distobuccal, and distolingual roots of three-rooted MFMs, respectively. The distance from the buccal bone to each root was longer in men than in women. The largest distance for complete root resection was detected for the distal root in two-rooted MFMs and for the distolingual root in three-rooted MFMs.

Conclusions

The prevalence of three-rooted MFMs is common in the Mongoloid population. The distance from the buccal bone to root apex differs according to root configurations and sex. Surgical access to the distolingual root is difficult because of the long access distance.