Proximity of the mandibular canal to the tooth apex

Measurement of the mandibular canal and mandibular incisive canal using cone beam tomography in adults from South Brazil

PURPOSE

To identify and measure the distance from the dental apices to the mandibular (MC) and mandibular incisive (MIC) canals, the diameter of the MC and the distances of the mental foramen (MF).

METHODS

In this retrospective study, cone-beam computed tomography scans of 144 adult patients (males and females) from a dental school in South Brazil were evaluated. Cross-sections were selected on the MC and the MIC paths, perpendicular to the mandibular base, and measurements were taken from the dental apices to the mandibular cortices. The measurement and location of the mandibular and mental foramen on both sides were compared. Paired t-tests compared sides, while Student's t-tests compared sexes (P < 0.05).

RESULTS

The distance from the dental apices to the upper wall of the MC was closest in the third molar and farthest in the central incisor region. In both sexes and sides, the path of the MC is in most cases lingually in the molar regions and moves to the buccal region from the second premolar. The MF emerges in the regions between the premolars or near the second premolar.

CONCLUSION

The results of this study highlight the importance of evaluating specific individual characteristics of a given population.

Reliability of the AI-Assisted Assessment of the Proximity of the Root Apices to Mandibular Canal

Background: This study evaluates the diagnostic accuracy of an AI-assisted tool in assessing the proximity of the mandibular canal (MC) to the root apices (RAs) of mandibular teeth using computed tomography (CT). Methods: This study involved 57 patients aged 18-30 whose CT scans were analyzed by both AI and human experts. The primary aim was to measure the closest distance between the MC and RAs and to assess the AI tool's diagnostic performance. The results indicated significant variability in RA-MC distances, with third molars showing the smallest mean distances and first molars the greatest. Diagnostic accuracy metrics for the AI tool were assessed at three thresholds (0 mm, 0.5 mm, and 1 mm). Results: The AI demonstrated high specificity but generally low diagnostic accuracy, with the highest metrics at the 0.5 mm threshold with 40.91% sensitivity and 97.06% specificity. Conclusions: This study underscores the limited potential of tested AI programs in reducing iatrogenic damage to the inferior alveolar nerve (IAN) during dental procedures. Significant differences in RA-MC distances between evaluated teeth were found.

Mandibular canal assessment in dentate and edentulous ridges of 400 Iraqi Arab and Kurdish populations using cone beam computed tomography

Objectives

This study aims to compare differences in mandibular canal (MC) location between dentate and edentulous ridges, in the second premolar region as well as the first, second, and third molar regions using cone beam computed tomography (CBCT) of Arabic and Kurdish Iraqi populations.

Materials and Methods

CBCT images of 400 subjects (200 Arabs, 200 Kurds) were collected from radiological archives. RadiAnt DICOM software (Medixant, Poland) was used for image analyses. Measurements were performed from MC to buccal and lingual alveolar crests and to buccal, lingual, and inferior aspect of the mandible for both dentate and edentulous ridges. Additionally, distance to the most superior aspect of residual edentulous ridge were performed. Independent t-test and Mann-Whitney U Test were performed utilising SPSS v.26.

Results

Distances from MC to buccal and lingual alveolar crests were consistently lower in edentulous ridge compared to dentate ridge across all teeth regions. Distances to lingual and inferior border of the mandible were higher in edentulous ridge compared to dentate ridge of all teeth regions. Distances to buccal surface of the mandible varies with fluctuations of dentate and edentulous ridges displaying higher measurements. Distance to superior aspect of residual edentulous ridge revealed mean values in the range of 13.45 to 15.69 mm in Arabs and 13.96 to 16.37 mm in Kurds.

Conclusions

Discrepancy in vertical position of MC was observed between dentate and edentulous ridges within Arab and Kurd populations. Horizontal position of MC was unaffected by tooth loss and found to be closer to lingual surface of all molars. The residual alveolar ridge was sufficient to accommodate the common length and width of dental implants.

Clinical significance

The findings could play a crucial role in planning surgical interventions of the mandible, helping to prevent complications that might arise due to inadequate preoperative assessments.

A Novel Approach for Orthodontic Extrusion Prior to Intentional Replantation: A Case Report

AIM

This case report aimed to present a novel surgical technique involving orthodontics luxation of the offended tooth using miniscrew prior to performing intentional replantation (IR) to remove an extruded separated instrument that injured the inferior alveolar nerve (IAN).

BACKGROUND

Intentional replantation is a dental procedure that involves extracting a tooth, managing the root canal, and then reinserting the tooth back into its socket. This procedure is typically used as a last resort when other treatment options have failed or are not possible. Intentional replantation can be successful in preserving the tooth and preventing tooth loss, but it is important to note that there are risks involved. Maintaining the viability of the periodontal ligament (PDL) is a pivotal step to achieve a favorable outcome.

CASE DESCRIPTION

A 15-year-old female patient came to the clinic complaining of electric-like pain in the left mandibular posterior area that radiated to the left ear and sometimes caused a headache. Upon clinical and radiographic evaluation, extruded endodontic file from the mesial root of the left first molar that penetrated the IAN canal was noticed. Nonsurgical root canal retreatment was performed, which failed to retrieve the separated file. Orthodontics luxation of the offended tooth was done 2 weeks before the surgical intervention using a miniscrew to induce PDL inflammation, which increased the tooth mobility and PDL volume, facilitating the atraumatic extraction and reduced the risk of complications, such as root resorption and ankylosis. Then, IR was performed, and the extruded file was successfully retrieved. Three months follow-up showed complete recovery of the endodontics-related IAN injury symptoms. Preapical radiographic evaluation and cone-beam computed tomography scan showed complete healing of the periapical radiolucency/area of low density and complete formation of the PDL space and lamina dura around the resected roots.

CONCLUSION

This novel approach using a miniscrew suggests a noninvasive technique that minimizes the damage to the offended tooth surrounding tissues as well as minimizing the morbidity of the adjacent teeth and the vital anatomical structures.

CLINICAL SIGNIFICANCE

Multidisciplinary comprehensive preplanning of complicated cases is essential to maximize treatment efficiency. The orthodontic extrusion facilitates the extraction process that helps in preserving the PDL, and ultimately increases the survivability of the teeth. How to cite this article: Alharbi MA, Alghamdi BA, Alswajy WA, et al. A Novel Approach for Orthodontic Extrusion Prior to Intentional Replantation: A Case Report. J Contemp Dent Pract 2023;24(11):895-901.

An evaluation of mandibular canal variations: a systematic review and meta-analysis

The inferior alveolar nerve and vessels are carried via the mandibular canal, which extends bilaterally from the inferior alveolar foramen to the mental foramen. Bifid and trifid mandibular canals result from abnormal fusions of nerve canals. The purpose of this study was to provide an up-to-date and comprehensive analysis of the prevalence of mandibular canal variations among healthy adults, and to identify any potential ethnic, sex, or laterality predilections. The prevalence of the bifid mandibular canal was 18.87% and that of the trifid canal 1.3%. Unilateral variants were three times commoner than bilateral. Each mandibular half had four canals emanating from separate openings on the lingual surface of the mandibular ramus. Retromolar and forward canals were the predominant subtypes, followed by dental; buccolingual were the least frequent. The mean length and diameter of the bifid mandibular canal were 13.62 mm and 1.63 mm, respectively. The possibility of a bifid mandibular canal is a crucial consideration in dental medicine. Because anatomical variations of the mandibular canal are fairly common, awareness of them is essential for anatomy teachers and for surgeons who operate in the oromaxillofacial region.

In Vitro Diagnostic Accuracy and Agreement of Dental Microscope and Cone-Beam Computed Tomography in Comparison with Microcomputed Tomography for Detection of the Second Mesiobuccal Canal of Maxillary First Molars

OBJECTIVES

The percentage of failure of endodontically treated maxillary molars is relatively high; one main reason is that the second mesiobuccal canal (MB2) is missing. Some techniques have been proposed for detection of the MB2. This study was aimed at assessing the diagnostic accuracy and agreement of the dental microscope and cone-beam computed tomography (CBCT) in comparison with microcomputed tomography (micro-CT) for detection of the MB2 of maxillary first molars in vitro.

MATERIALS AND METHODS

This in vitro, experimental study evaluated 71 permanent maxillary first molars that were stored in 100% humidity at room temperature. The teeth were mounted in 9 silicone dental arches to the level of their cementoenamel junction (8 teeth in each arch). The blocks underwent CBCT in a XG3D scanner. Access cavity was then prepared, and the teeth were inspected by a surgical microscope for negotiation of the MB2. Also, micro-CT images were obtained from the teeth to serve as the gold standard. CBCT and micro-CT images were observed by two examiners twice with a 2-week interval.

RESULTS

The frequency of the MB2 detected by dental microscope was significantly lower than micro-CT (P < 0.001) and CBCT (P = 0.008); no significant difference existed between micro-CT and CBCT in this respect. The sensitivity, specificity, positive predictive value, and negative predictive value of CBCT for detection of MB2 were 92.6%, 100%, 100%, and 81%, respectively.

CONCLUSION

CBCT is superior to the dental microscope for detection of the MB2 of maxillary first molars and can be used for this purpose in the clinical setting with adequate accuracy.

Inferior alveolar nerve topography and its bifurcation features: a cone beam computed tomography evaluation

BACKGROUND

Mandibular canal (MC) is the most important vital structure in mandible to prevent from complications such as bleeding and paresthesia. The aims of the present study were to inform the features (diameter, distances to the mandibular borders, and distance to tooth apex) of the MC for each posterior tooth region, and to present the bifurcation features of the MC.

METHODS

Four-hundreds-eighteen MC images of 209 patients were evaluated. The parameters were recorded from right and left hemi-mandibles for each posterior teeth region: 1) MC diameter; 2) MC and mandibular basis distance; 3) MC and crest distance; 4) MC and tooth apex distance; 5) MC and buccal plate distance; 6) MC and lingual plate distance; and 7) possible implant length (the distance between 2 mm coronal of the MC and 1 mm apical of the crest). Additionally, MC bifurcation type and bifid mandibular canal length were noted for right and left sides.

RESULTS

While higher MC diameter values were recorded at molars, MC diameter in first premolars bilaterally were the lowest. In premolars, MC and mandibular basis distance showed higher values than molars. There was a trend of decrease in MC and crest distance from molars to premolars. The highest MC and tooth apex distance was measured in second molar; however, the lowest was in the first premolar. Additionally, MC and buccal plate distances were higher in molars, while MC and lingual plate distances were higher in premolars. Possible implant length in first premolar was the lowest, when it was the highest in second molars.

CONCLUSIONS

For simulating overall MC topography, it extended bucco-coronally from molars to premolars. Due to this topography, possible implant length increased from premolars to molars.

Analysis of Root Canal Anatomy of Mandibular Permanent Incisors in Saudi Subpopulation: A Cone-Beam Computed Tomography (CBCT) Study

This study aimed to evaluate the root canal anatomy of central and lateral mandibular incisors in a Saudi population using cone-beam computed tomography (CBCT). Overall, 1370 CBCT images of central (687) and lateral (683) mandibular incisors of Saudi patients who attended the Dental College at King Saud University in Riyadh were examined. The number of roots and canals, canal configuration types, symmetry between bilateral incisors, and the effect of gender and age were determined. For data analysis, the chi-square test was applied, and the p value was set at ≤0.05. Only one tooth had two roots, and 41% of mandibular incisors had two canals. The most common canal configuration type observed was type I (58.83%), followed by type III (28.24%). Type V was more common in men (8.31%) than women (3.9%). Bilateral symmetries were higher in the mandibular central incisors regarding the root and canal numbers and the canal configuration types (100, 100, and 97.92%, respectively) than in the lateral incisors (99.69, 98.16, and 97.24%, respectively). The 21-40 age group showed a higher proportion of teeth with more complicated root canal anatomy than the other age groups. More than one canal in mandibular incisors is a common finding in the Saudi subpopulation, with the type III canal configuration as the most common type.

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.

Compression of the Inferior Alveolar Canal by Mandibular Third Molar among Images Taken from Patients Visiting Dental Imaging Centres of Kathmandu: A Descriptive Cross-sectional Study

INTRODUCTION

Third molars are common teeth to be impacted. The position of mandibular third molar is such that it is in close contact with inferior alveolar canal which may lead to nerve damage during its removal. So, this study was conducted to find out the prevalence of compression of inferior alveolar canal by mandibular third molars.

METHODS

This descriptive cross-sectional study was conducted on images collected from Dental Imaging Centers of Nepal from 25th June 2020 to 15th February 2021 after obtaining ethical clearance from Nepal Health Research Council (Reference number: 2100). A convenience sampling method was used to collect 433 cone-beam computed tomography images showing the relation between the third molars and inferior alveolar canal. Data were analyzed using the Statistical Package for the Social Sciences version 16. Point estimate at 95% confidence interval was calculated along with frequency and proportion for the binary data.

RESULTS

Out of 433 images, 135 (31.17%) (26.80-35.53 at 95% Confidence Interval) images showed compression of inferior alveolar nerve by mandibular third molar. The study result indicated that 16 (11.85%) buccally placed, 50 (37.03%) lingually placed and 69 (51.11%) inferiorly placed inferior alveolar canal were compressed by apices of mandibular third molars.

CONCLUSIONS

The prevalence of compression of inferior alveolar canal by mandibular third molar was found to be similar to other studies done in similar settings. Compression of the canal was more evident when inferior alveolar canal is situated lingually.

The influence of age, sex, and tooth type on the anatomical relationship between tooth roots and the mandibular canal

Purpose

Cone-beam computed tomography (CBCT) reconstructions were analysed to elucidate factors affecting the anatomical relationship between tooth roots and the mandibular canal(MC).

Materials and Methods

Images of 300 volumetric tomography scans of patients aged between 20 and 79 years old (167 women and 133 men) were analysed. The mean distances between 2,053 dental root apices and the internal border of the MC were obtained by measuring the horizontal and vertical distances on coronal CBCT images. The actual distance was then calculated mathematically with the Pythagorean formula. The statistical significance of differences between men and women was assessed using the Mann-Whitney test. Correlations with patient age were evaluated with the Spearman rank correlation coefficient.

Results

The mean distances ranged from 2.17 mm, for single right third molar roots in women, to 8.02 mm for single left third molar mesiolingual roots in men. The mean distances measured for the mandibular right second molar mesial roots and the right second premolar roots were larger in men than in women. Age showed a significant positive correlation with the measured distances for mesial and distal roots of the first and second molar on both sides and the right third molar, mesiolingual roots of the left third molar, and single roots of the right third molar.

Conclusion

The root-to-mandibular canal distance depended on age and the type of tooth. In 2 root types, this distance was impacted by sex.

Mandibular Canal Location and Cortical Bone Thickness in Males and Females of Different Age Groups: A Cone-beam Computed Tomography Study

AIM: The purpose of the study was to measure and compare the prevalence of mandibular canal (MC) location variations in regard to mandibular first molars in both genders at different age groups. METHODS: A retrospective study was performed on 80 cone-beam computed tomography scans. Distance between MC and apical apices of first molars, buccal and lingual cortical plates was measured in both sides. RESULTS: 80 scans with 160 sides were analyzed. Distances was measured bilaterally for all scans with mean (5.22 ± 0.77) in men versus (4.1 ± 0.7) in women at group age 31–40 apical to apices of first molars. The mean was (3.77 ± 0.62) in men versus (2.81 ± 0.47) in women at same age group at buccal side, lingually the mean was (4.02 ± 0.67) in men versus (3.67 ± 0.26) in women in the same age group. CONCLUSION: Our study showed that there were decrease in measurements in older age group in both genders and in female groups more than male groups but with no statistical significant difference.

Three Dimensional mapping of the root apex: distances between apexes and anatomical structures and external cortical plates

This study aimed to determine the mean distances between apexes of the maxillary posterior teeth and the maxillary sinus, between apexes of the mandibular posterior teeth and the mandibular canal, and between the root apexes of all teeth and the adjacent cortical plates. A total of 800 cone-beam computed tomography (CBCT) scans (400 maxillary and 400 mandibular) were obtained from patients indicated for several treatments. The proximity between apexes and anatomical structures, and the relationship between apexes and adjacent cortical plates were assessed together with the risk of over-instrumentation. Paired-sample comparisons were performed by using the paired t-test. The means were compared by ANOVA, Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner tests. a) Most of the apexes classified as A (high-risk proximity) were observed in maxillary first and second molars, in mandibular first and second molars, and in second premolars in relation to near anatomical structures. b) A predominance of class A (86.42%) was noticed in the first premolars, between apexes of maxillary teeth and adjacent cortical plates. c) The distance between apexes of mandibular teeth and buccal cortical plates showed a predominance of medium-risk proximity (B) in all the groups, except the first premolars, with the highest risk (82.22%), and the second molars, with low-risk proximity (C) to distal and mesiobuccal apexes (91.77% and 89.62%). CBCT images are important for endodontic diagnosis and treatment, since many teeth have high risk proximity to near anatomical structures and adjacent cortical plates.

Computed Tomography for the Assessment of the Potential Risk After Implant Placement in Fresh Extraction Sites in the Posterior Mandible

Immediate implant placement (IIP) is considered a reliable procedure, with survival rates of 94.9%-98.4%. Nevertheless, in the posterior mandible, it poses a high risk of damage to anatomic structures. The aim of this study was to determine the risk of anatomic structures injury associated with IIP in the posterior mandible based on apical primary stability, respecting a safe distance from the inferior alveolar nerve and lingual plate, and to evaluate the influence of different factors on those risks. Pre-extraction cone beam computed tomography scans of 100 patients were retrospectively analyzed. Measurements were taken from tooth apices to lingual plate and to mandibular canal. Values of <4 mm of the former and <6 mm of the latter were categorized as considerable risk. Values of <2 mm at both measurements were considered high risk. Two-sided P < .05 was considered statistically significant. Mean root-to-alveolar canal distance was 7.6 ± 2.7 mm in the first molar, 6.5 ± 3mm in the second premolar, and 5.4 ± 3 mm in the second molar (P < .005). The mean distance to the outer lingual cortex was 3.9 ± 2.1 mm in the first molar and 3.2 ± 0.1 mm in the second molar. Thus, second molars were at higher risk of inferior alveolar nerve injury and lingual plate perforation during IIP. Background factors associated with higher IIP risk were female sex and age < 40 years. In the mandible, the anatomic risk posed by IIP is greatest for second molars and lowest for first molars. Several background factors affect the distances between root apices and the mandibular canal.

The anatomical relationship between the roots of erupted permanent teeth and the mandibular canal: a systematic review

PURPOSE

This study reviewed the literature on the position of the mandibular canal (MC) relative to the root apices (RA) of neighbouring teeth using cone beam computed tomography (CBCT).

METHODS

The authors searched the PubMed, Scopus, EBSCO Dentistry and Oral Sciences Source, Cochrane and Lilacs databases for relevant English-language articles with no year limitations published through January 25, 2018.

RESULTS

The search identified 888 articles, 12 of which met the inclusion criteria. Three groups were found based on the measuring method: the shortest distance from the RA to the MC, the vertical distance from the RA to the MC, or the distance from the RA to the superior cortical bone of the MC. In the first and second groups, the shortest distances to the canines, first premolars, second premolars, first molars, second molars, and third molars were 3.8 mm, 4.76 mm, 1.65 mm, 1.23 mm, 0.64 mm, and 1.28 mm, respectively. In the third group, the shortest distances to the second premolars, first molars, and second molars were 2.71 mm, 3.82 mm, and 1.4 mm, respectively.

CONCLUSIONS

The distance from the MC to the RA was generally shorter in females and younger people, with decreasing distances in patients over 60 years old, and depended on the tooth type.

TRIAL REGISTRATION

The protocol for this systematic review was registered on PROSPERO (CRD42018085478).

Inferior alveolar nerve canal position in relation to mandibular molars: A cone-beam computed tomography study

Objective

This study was carried out to prevent the risk of iatrogenic injuries to the inferior alveolar nerve (IAN) canal associated with various surgical interventions in the area of mandibular molars, by using cone-beam computed tomography (CBCT).

Materials and Methods

The present retrospective study was carried out by using CBCT of 100 patients between 18 and 40 years of age group. The linear measurements were made in relation to the 1^st and 2^nd mandibular molars on both the sides. Linear distances between buccal and lingual aspects to the mandibular, buccal, and lingual cortical bone thickness; IAN canal diameter; and the superior corticated border of the IAN canal from the periapex of the 1^st and 2^nd mandibular molars. The statistical evaluation was done using SPSS V.20 (SPSS: an IBM company), and P < 0.05 was considered statistically significant.

Results

Both genders of all age groups showed statistically significant result (P < 0.00). All the linear measurements were statistically significant in relation to both the 1^st and 2^nd mandibular molars (P < 0.005), and also the bilateral comparison of the linear measurements showed statistically significant difference in relation to the mandibular 2^nd molar (P < 0.03) and 1^st molar (P < 0.04) among both the sexes.

Conclusion

Clinicians should be aware of the proximity of root apices and cortical plates to the mandibular canal when performing surgical and root canal procedures in the posterior mandible to avoid serious nerve injuries.

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

Objectives:

To evaluate the relationship of the first and second mandibular molar roots to the inferior alveolar canal (IAC) and cortical plates using cone beam computed tomography (CBCT) in the Saudi population.

Methods:

Scans of 60 patients were collected retrospectively from the dental hospital database in King Saud University, Riyadh, Kingdom of Saudi Arabia. Measurements of the right and left first and second mandibular molars for each dental root and the mandibular bone thickness were determined. The position of the IAC was estimated using axial, coronal, and sagittal views. Three examiners performed the measurements independently.

Results:

The mean distance between the root apices of the mandibular molars and the IAC ranged from 1.68-4.79 mm, whereas the mean distance from the outer surface of the buccal cortical plate to the buccal root surface ranged from 2.33-6.72 mm. Similarly, the mean distance from the outer surface of the lingual cortical plate to the lingual root surface ranged from 2.62-4.80 mm. Finally, the mean distance from the outer surface of the lingual cortical plate to the outer surface of the buccal cortical plate was 11.93-13.19 mm.

Conclusion:

The measurements reported in this study may be of value to practitioners treating Saudi patients, as they need to be familiar with the distance of the mandibular first and second molars in relation to the IAC and surrounding cortical plates to accurately assess and plan endodontic surgeries, surgical extractions, and implant placements.

Maxillary Incisive Canal Characteristics: A Radiographic Study Using Cone Beam Computerized Tomography

Background

The incisive canal located at the midline, posterior to the central incisor, is an important anatomic structure of this area to be considered while planning for immediate implant placement in maxillary central incisor region. The purpose of the present study is to assess incisive canal characteristics using CBCT sections.

Materials and Methods

CBCT scans of 79 systemically healthy patients, with intact maxillary incisors, were evaluated by two calibrated and independent examiners. Assessments included (1) mesiodistal diameter, (2) labiopalatal diameter, (3) length of the incisive canal, (4) shape of incisive canal, and (5) width of the bone anterior to the incisive foramen.

Results

The mean width of the foramen labiopalatally and mesiodistally was 3.12 ± 0.94 mm and 3.23 ± 0.98 mm, respectively. Mean canal length was 18.63 ± 2.35 mm and males have significantly longer incisive canal than females. The mean width of bone anterior to the incisive canal was 6.32 ± 1.43 mm. As age of the subjects increased, incisive foramen diameter and incisive canal length were found to be increased. Cylindrical shaped incisive canals were seen in most of the individuals followed by funnel shaped and hour-glass shaped canals, and banana-like canal is least prevalent type.

Conclusion

The findings from the present study suggest that the diameter and length of incisive canal vary among different individuals and presence of very thin bone anterior to the canal would suggest that a pretreatment CBCT scan is a valuable tool to evaluate anatomic variations, morphology, and dimensions of incisive foramen before immediate implant placement in maxillary central incisor region.

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

OBJECTIVE

The purpose of this study is to evaluate the relationship between anatomic structures and mandibular posterior region using cone-beam computed tomography (CBCT) in terms of endodontic surgery.

METHODS

A total of 150 CBCT images were used to investigate the proximity of the anatomical structures and the mandibular posterior teeth. The buccal and lingual bone thickness overlying each root, buccolingual, and mesiodistal dimension of the roots were measured at the level of 3 mm apical resection, and the mental foramen (MF) distance to the premolar teeth and the distance of the mandibular canal (MC) to all the posterior teeth were measured.

RESULTS

The thinnest part of the buccal cortical bone was measured in the first premolar teeth (1.70 mm) and in the mesial root of the first molar (2.25 mm) while the thickest region was measured in the distal root of the second molar tooth (6.95 mm). The maximum amount of substance to be removed was measured at the distal root of the second molar tooth (11.26 mm), and at least the first premolar tooth (5.52 mm) was measured for buccal resection. The distal root of the second molar tooth was found to be the closest tooth root to the MC with a mean of 2.75 mm, and the closest distance was measured as 0 mm.

CONCLUSIONS

It is important to evaluate the parameters such as mandibular buccal and lingual bone thickness, location of the MC and the MF, and root size for atraumatic endodontic surgical approach. Evaluation of these data before endodontic surgery provides guidance to the clinician in the planning of endodontic surgery.

CLINICAL RELEVANCE

The mandibular posterior region, which is difficult to reach with traditional surgical approach, is now easily reached using an operation microscope. For this reason, endodontic surgical procedures have become popular in mandibular posterior teeth. Therefore, the relationship between the mandibular posterior teeth and anatomical structures that are important in the planning of surgical access line is examined in this study.

Сross-sectional anatomic study of direct positional relationships between mandibular canal and roots of posterior teeth using cone beam computed tomography

Objectives: To establish the frequency of the various types of direct contacts of the root apices with the wall of the mandibular canal and to determine gender differences in number of such contacts in a selected Belarusian population using cone beam computed tomography. Methodology: One hundred and two cone beam computed tomography scans were analyzed to classify the types of contact and three-dimensional relationship between the mandibular teeth and the mandibular canal. Results: The direct contact between the teeth and the mandibular canal was observed in 63.7% of patients. Overall 300 roots of 189 teeth were in direct contact with the mandibular canal: 9.3% were second premolars, 14.7% were first molars, 33.8% were second molars and 50.0% were third molars. There were no statistically significant differences in the number of teeth with direct contact with the mandibular canal between males and females. Conclusion: The direct contact of the root apices with the mandibular canal was most often found in the second and third molars. The root apices of the third molars had the greatest variability of location relatively to the mandibular canal.

A cone-beam computed tomography study of the anatomical relationships between mandibular teeth and the mandibular canal, with a review of the current literature

The purpose of this study was to evaluate age- and sex-related changes in the anatomical relationships between the roots of the molars and premolars and the mandibular canal using cone-beam computed tomography (CBCT) images. A total of 243 patients (116 males, 127 females) aged 16-83 years for whom previous CBCT scans were available were enrolled in this study. The patients were subcategorized by sex and age (Group I, <21 years; Group II, 21-40 years; and Group III, >40 years). The distances between the mandibular canal and the molars and premolars were measured. The mandibular canal was significantly closer to the root apices of the second and third molars than to the apices of other evaluated teeth (p < 0.05). All measurements were significantly higher in male than in female subjects (p < 0.05). Group I subjects exhibited significantly shorter distances between the mandibular canal and root apices of the first and second premolars, and the molars, than those of Group II and III subjects (p < 0.05). Direct contact relationships were found in 1.6%, 3.3%, 3.3%, 16%, and 32.2% of teeth (running from the first premolar to the third molar, respectively). Age and sex influenced the anatomical relationships between mandibular teeth and the mandibular canal, and these should be considered when planning endodontic and surgical procedures to avoid potential nerve injury.

Distances from the root apices of posterior teeth to the maxillary sinus and mandibular canal in patients with skeletal open bite: A cone-beam computed tomography study

Purpose

This study determined and compared the distances from the maxillary root apices of posterior teeth to the floor of the maxillary sinus, or maxillary sinus distances (MSDs), and the distances from the mandibular root apices of the posterior teeth to the mandibular canal, or mandibular canal distances (MCDs), in Thai subjects with skeletal open bite and skeletal normal bite.

Materials and Methods

Pretreatment cone-beam computed tomography (CBCT) images were obtained from 30 Thai orthodontic patients (15 patients with skeletal normal bite and 15 with skeletal open bite) whose ages ranged from 14 to 28 years. The CBCT images of the patients were processed and measured using the Romexis Viewer program. The MSDs and MCDs from the root apices of the maxillary and mandibular second premolar, first molar, and second molar to the maxillary sinus floor or the mandibular canal were measured perpendicularly to the occlusal plane. The Student t test was used for comparisons between the 2 groups.

Results

The greatest mean MSDs were from the root apex of the second premolars in both groups, whereas the least mean MSDs were from the mesiobuccal root apex of the second molars. The greatest mean MCDs were from the mesial root apex of the first molars, whereas the least mean MCDs were from the distal root apex of the second molars.

Conclusion

There were no differences in the mean MSDs or the mean MCDs between the skeletal normal bite group and the skeletal open bite group.

Surgical Approach to Foreign Material Within the Mandibular Canal Due to Iatrogenic Factors

This clinical report describes a relatively infrequent patient with inferior alveolar nerve damage caused by foreign material within the mandibular canal, which is one of the most severe complications of endodontic therapy. Although the circumstance is uncommon, it can have extremely unfavorable consequences for patients, such as anesthesia and paresthesia. In the present case, a patient suffered pain and severe paresthesia in the corresponding area after routine endodontic therapy. Several treatments were conducted to relieve the patient's symptoms, ranging from medication to tooth extraction, but all were of no avail. Ultimately, surgical exploration and debridement were performed with assistance of a customized surgical template. Once the foreign material was excavated, the exacerbation of condition was terminated and gradually reverted. This patient illustrates that special attention is required when undertaking intracanal procedures of lower posterior teeth so as to avoid iatrogenic damage to inferior alveolar nerve. Even more significant, when above-mentioned condition occurs, prompt surgical intervention is essential for recovery of sensation. It also demonstrates the advantages of applying surgical template and piezosurgery in removal of foreign material within the mandibular canal.

The Reliability of Panoramic Radiography Versus Cone Beam Computed Tomography when Evaluating the Distance to the Alveolar Nerve in the Site of Lateral Teeth

BACKGROUND The aim of this study was to compare the reliability of panoramic radiography (PR) and cone beam computed tomography (CBCT) in the evaluation of the distance of the roots of lateral teeth to the inferior alveolar nerve canal (IANC). MATERIAL AND METHODS 100 PR and 100 CBCT images that met the selection criteria were selected from the database. In PR images, the distances were measured using an electronic caliper with 0.01 mm accuracy and white light x-ray film reviewer. Actual values of the measurements were calculated taking into consideration the magnification used in PR images (130%). Measurements on CBCT images were performed using i-CAT Vision software. Statistical data analysis was performed using R software and applying Welch's t-test and the Wilcoxon test. RESULTS There was no statistically significant difference in the mean distance from the root of the second premolar and the mesial and distal roots of the first molar to the IANC between PR and CBCT images. The difference in the mean distance from the mesial and distal roots of the second and the third molars to the IANC measured in PR and CBCT images was statistically significant. CONCLUSIONS PR may be uninformative or misleading when measuring the distance from the mesial and distal roots of the second and the third molars to the IANC.

Relationship between the Mental Foramen, Mandibular Canal, and the Surgical Access Line of the Mandibular Posterior Teeth: A Cone-beam Computed Tomographic Analysis

INTRODUCTION

The purpose of this study was to investigate the relationships between the location of the mental foramen (MF) and the mandibular canal (MC) and the surgical access line (SAL) of the mandibular posterior teeth using cone-beam computed tomographic (CBCT) scans.

METHODS

CBCT scans of 204 subjects ranging in age from 18-76 years old were evaluated. The vertical and horizontal distances from the MF to the SAL of the mandibular premolars and first molars and the vertical distance from the MC to the SAL of the second premolars and first molars were measured via CBCT scans.

RESULTS

The average vertical distance between the MF and the SALs showed significant increases sequentially from the first premolars to the distal roots of the first molars, and the shortest average distance of 2.74 mm was obtained for the first premolars. The SALs of the second premolars were the closest to the MF in the horizontal direction with an average distance of 1.5 mm. In 19.9% of the cases, the vertical and horizontal distances between the MF and the SALs of the second premolars were less than 2 mm. In addition, the MF was located superior to the root apices in 6.62% of the cases. The majority of the SALs were located at a vertical distance from the MC that was more than 2 mm. Men and women exhibited significant differences in both the horizontal distance from the MF to the SALs of the first premolars and the vertical distance from the MC to the SALs of the second premolars.

CONCLUSIONS

To improve the success of endodontic microsurgery, adequate knowledge of the anatomic relationships between the location of the MF and MC and the SAL of the mandibular posterior teeth is indispensable to surgeons.

Computed tomography: Will the slices reveal the truth

With the advances in the field of imaging sciences, new methods have been developed in dental radiology. These include digital radiography, density analyzing methods, cone beam computed tomography (CBCT), magnetic resonance imaging, ultrasound, and nuclear imaging techniques, which provide high-resolution detailed images of oral structures. The current review aims to critically elaborate the use of CBCT in endodontics.

Accidental injury of the inferior alveolar nerve due to the extrusion of calcium hydroxide in endodontic treatment: a case report

During clinical endodontic treatment, we often find radiopaque filling material beyond the root apex. Accidental extrusion of calcium hydroxide could cause the injury of inferior alveolar nerve, such as paresthesia or continuous inflammatory response. This case report presents the extrusion of calcium hydroxide and treatment procedures including surgical intervention. A 48 yr old female patient experienced Calcipex II extrusion in to the inferior alveolar canal on left mandibular area during endodontic treatment. After completion of endodontic treatment on left mandibular first molar, surgical intervention was planned under general anesthesia. After cortical bone osteotomy and debridement, neuroma resection and neurorrhaphy was performed, and prognosis was observed. But no improvement in sensory nerve was seen following surgical intervention after 20 mon. A clinician should be aware of extrusion of intracanal medicaments and the possibility of damage on inferior alveolar canal. Injectable type of calcium hydroxide should be applied with care for preventing nerve injury. The alternative delivery method such as lentulo spiral was suggested on the posterior mandibular molar.

Proximity of the Mandibular Canal to Teeth and Cortical Bone

INTRODUCTION

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

Our study shows that age, gender, and region have an influence on the location of the MC in the second molar area.

Number of accessory or nutrient canals in the human mandible

OBJECTIVES

The aim of the study was to assess the presence, location and the number of accessory or nutrient canals in the body of the mandible by means of cone beam CT images, obtained with the Planmeca ProMax® 3D Max device.

MATERIAL AND METHODS

Seventy-four cone beam images of the mandible from adult patients (37 males and 37 females) who were imaged for dental implantology planning or third molar extraction were used to assess the number and location of accessory or nutrient canals. All images were taken with the same machine (Planmeca® ProMax 3D Max) at 200-, 400- or 600-μm resolution. Distinction was made between canals entering or exiting the mandible superior or inferior of the inferior alveolar canal and between similar canals superior or inferior of the genial tubercula.

RESULTS

The number of accessory canals varied between nil to 11. No statistical significant difference between males and females was found with regard to the number or location of accessory canals in the mandible. Only 5.4% of patients had no accessory canals. One to five accessory canals were found in 71.6%, and 23% of patients had more than five accessory canals. The majority (81%) of patients had between two and six accessory canals.

CONCLUSION

It seems that subjects showing no accessory canals whatsoever should be considered exceptional as more subjects with than without accessory canals in the body of the mandible were found.

CLINICAL RELEVANCE

These results are clinically relevant for mandibular surgery and mandibular local anaesthesia.

Visibility of mandibular canal on panoramic radiograph after bilateral sagittal split osteotomy (BSSO)

PURPOSE

This study aimed to assess the visibility of the mandibular canal (MC) on panoramic radiographs after bilateral sagittal split osteotomy (BSSO), and to investigate what factors affect this MC visibility.

METHODS

We assessed MC visibility on panoramic radiographs of 200 BSSO patients. Images were acquired preoperatively (T0), immediately postoperatively (T1), 6 months postoperatively (T2), and 1 year postoperatively (T3), from three different predetermined regions of the mandible: the angle (Angle), distally to the second molar (M2), and mesially to the first molar (M1). All analyses were performed using SAS version 9.22.

RESULTS

The visibility of the MC was registered preoperatively in over 96 % (387/400) of the measurements at the angle of the mandible, 79 % (317/400) at M2, and <63 % (251/400) at M1. MC visibility decreased immediately after the operation and increased thereafter. Region of the mandible (P ≤ 0.0001), plate removal (P ≤ 0.0001), time of assessment (P ≤ 0.0001), and age (P = 0.0034) were the important predictors of whether MC would be radiographically visible.

CONCLUSIONS

The visibility of the MC decreased immediately after BSSO, especially at the operation site (M2 and M1), while maximum MC visibility was achieved at 12 months postoperatively in our series. Since MC was not visible at the operation site after BSSO for 50 % of the subjects, it may be necessary to use additional visualization modalities for postoperative patient assessment in this region.

Is there a gender difference in anatomic features of incisive canal and maxillary environmental bone?

OBJECTIVES

The effect of gender on anatomic structures and various body systems were illustrated in the literature. The purpose of this study was to identify the influence of gender and tooth loss on incisive canal characteristics and buccal bone dimensions in the anterior maxilla.

MATERIALS AND METHODS

Computed tomographies (CTs) of 417 male and 516 female patients in four dental clinics were included in this study. The diameter and the length of the incisive canal; width and the length of the bone anterior to the canal; palatal bone length, root length, and root width of the central incisor teeth were measured and recorded from CT sections.

RESULTS

Mean incisive canal length was 11.96 ± 2.73 mm and 10.39 ± 2.47 mm in men and women, respectively, (P < 0.05). In men, mean canal diameter was 2.79 ± 0.94 mm whereas in women it was 2.43 ± 0.85 mm and this difference was statistically significant (P < 0.05). Men had significant higher buccal bone dimensions (length and width of the bone anterior to the canal) than women. Absence of teeth in the anterior maxilla decreased incisive canal length and buccal bone dimensions; however, canal diameter remain unchanged.

CONCLUSIONS

Present results suggested a gender related differences in anatomic features of incisive canal and surrounding buccal bone. In addition, crestal canal diameter, buccal bone length, and thickness parameters might be different in distinct countries.

Imaging techniques in endodontics: an overview

This review provides an overview of the relevance of imaging techniques such as, computed tomography, cone beam computed tomography, and ultrasound, to endodontic practice. Many limitations of the conventional radiographic techniques have been overcome by the newer methods. Advantages and disadvantages of various imaging techniques in endodontic practice are also discussed.