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SUMMARY: A recent study found that the mandibular canal might be preferably called the inferior alveolar canal in recent publication years, certain journal categories, countries and departments with which the authors were affiliated. The canal can also be called the inferior dental canal that was not included in that study. This bibliometric analysis was conducted to evaluate the entire relevant literature, and to investigate if inferior alveolar canal was trending over the years. The Web of Science Core Collection electronic database was searched to identify publications exclusively mentioning mandibular canal, inferior alveolar canal, inferior dental canal, and publications mentioning them in combinations. Publication year, country of contributing authors, journal category, journal title, and citation count were recorded for the resultant publications. There were 1152 publications analyzed. Mandibular canal has always been the dominating term since the 1990s, whereas inferior alveolar canal seemed to become slightly more popular in the 2010s than in the past. Journals from dentistry, surgery, radiology, anatomy, and medicine all showed a preference towards mandibular canal. Leading dental surgery journals had a higher ratio of inferior alveolar canal usage than their dental radiology counterparts. Top 20 countries showed a preference towards mandibular canal except Saudi Arabia, which had 57.7 % of publications using inferior alveolar canal exclusively. Publications mentioning mandibular canal, inferior alveolar canal, and inferior dental canal did not differ in averaged citation count. The term mandibular canal was still dominating in all academic fields. The term inferior alveolar canal showed increased usage in the 2010s without an increasing trend. The argumentation of renaming mandibular canal as inferior alveolar canal has yet to accumulate considerable traction.

Lack of knowledge concerning the inferior alveolar canal anatomical variations had proven to increase the incidence of surgical complications, so the study aimed to assess the configuration and prevalence of bifid and trifid mandibular canals using cone beam CT in Egyptian subpopulation. Cone beam CT scans of 278 patients (530 hemi-mandibles) were included in the study, in which bifid and trifid mandibular canals or any other branching patterns were recorded and evaluated. Bifid canals were categorized following Naitoh classification, and the diameter of the main mandibular and accessory canals was measured. Bifid canals were detected in 181 canals (34%) while trifid canals in 46 canals (8.7%). Upon classifying the bifid canals, 78 canals showed forward type, 40 retromolar type, 33 dental type, and 7 canals showed buccolingual type. Two special bifid canals subtypes were reported in 23 canals and nine distinct patterns of trifid canals were reported in our study. In addition, unusual patterns of canal branching were reported in 5 cases. The mean diameter of the accessory canals was 1.18 ± .54 mm and the main canal was 3.98 ± 1.31 mm. This study reported a high prevalence (54%) of canal branching, which reinforces the importance of cone beam CT in pre-surgical planning.

Inferior alveolar nerve (IAN) damage following implant placement is a severe complication that can compromise a patient's quality of life. Previous studies have suggested that a safety zone of 2 mm, if maintained, might avoid this problem. This retrospective study evaluates implants placed in closer proximity to the IAN without resulting in any postoperative neurologic complications and suggests a new concept of safety distance. A total of 60 consecutive patients receiving 101 mandibular implants < 2 mm from the IAN were included in this study. All enrolled patients had a CBCT scan done for radiologic assessment before implant placement and following final restoration. Measurements were obtained through cross-sectional views using Simplant software. In patients without neurologic disturbances, a mean distance of +0.75 mm was seen from the closest portion of the implant to the nerve bundle. In cases where a direct transection and/or compression of the nerve was not observed, the patients did not experience neurosensory disturbances.

Introduction The general principles of anatomical terminology indicate that the "mandibular canal" should be named the "inferior alveolar canal" as it accommodates the inferior alveolar neurovascular bundles. Therefore, we performed a Delphi study to evaluate the current understanding and use of the terminology in different geographical regions and areas of expertise and to determine the appropriate terminology for this bony canal. Methods A Delphi panel was formed and questions sent and answered via email about: field of expertise (anatomy, oral surgery/oral and maxillofacial (OMF) surgery, oral radiology/OMF radiology, plastic surgery, ENT surgery, or dentistry with the exception of oral/OMF surgery and oral/OMF radiology), years of experience in the field of expertise, country currently working in, "what is the name of the bony canal that contains the inferior alveolar neurovascular bundle," and "what should the structure above be called, in general?" Results A total of 52 participants responded to the questionnaire. Half or more of the experts in anatomy, oral/OMF surgery, and ENT/Plastic surgery considered "mandibular canal" to be the most appropriate name for this bony canal. In contrast, more than half of all experts in oral/OMF radiology and dentistry, i.e., most fields of dentistry, considered "either mandibular canal or inferior alveolar canal" to be the appropriate name. Conclusions The results of the Delphi study and general principles suggest that an alternative term for the "mandibular canal" should be "inferior alveolar canal." This article is protected by copyright. All rights reserved.

Background: Mandibular third molar’s roots have close proximity to the inferior alveolar canal (IAC) and nerve. Inferior alveolar nerve injuries have been observed to occur more frequently when there is radiographic evidence of close contact of third molar roots to the IAC. Orthopan­tomogram is one of the commonly used diagnostic tools for evaluating the relationship between these two structures. There is lack of data regarding prevalence of these radiographic signs in Nepalese population. It was required to assess the reliability on the radiographic signs of relation­ship between the IAC and the third molar roots, to establish IAC as risk indicators for IAC exposure during extraction. Methods: A single centre cross-sectional descriptive study was designed where demographic data and radiographic signs of third molar roots proximity to IAC were obtained from imaging software records and descriptive analysis was performed with SPSS version 20. Results: One or more radiographic signs were observed in 49.6% of mandibular third molars. In­terruption of white line followed by narrowing of canal and darkening of roots was observed in decreasing order of frequency and no statistically significant association between sex, age and side of impacted third molar with presence of radiographic signs. Conclusions: Presence of one or more radiographic signs of proximity of mandibular third molar roots with IAC in nearly half of the cases. Clinicians should be aware of risk of nerve injury on pres­ence of these signs. Further investigation with cone beam computed tomography to rule out any nerve injury risk should be adopted into practice.

Objective: The aim is to evaluate the location and proximity of second and third molars roots to the inferior alveolar canal (IAC) and demographic factors associated with these proximities. Materials and Methods: Cone beam computed tomography scans were evaluated for 292 roots of 146 teeth from 40 patients. A radiologist read, measured, and evaluated the vertical and horizontal positions of the roots of the second and third molars in relation to the IAC. Results: No significant differences were found between the third molar roots and neighboring second molar roots in the closeness to the IAC. The most common horizontal relation was “roots above IAC” (54%) followed by “roots lingual to IAC” (41.78%), “roots buccal to IAC” (3.42%), and “IAC between the roots” (0.68%). No significant differences in second and third molar roots and their contrasting teeth in the proximity to IAC. The older age group had significantly higher vertical measurements between third molar roots and IAC. There were significantly larger vertical measurements in the right third molar roots to IAC in males than females. Conclusions: These anatomical relationships are important clinical knowledge to avoid potential surgical injury to the inferior alveolar nerve.

The aim of this study was to introduce a method to evaluate the risk of inferior alveolar nerve (IAN) injury following the extraction of impacted lower third molars. Two hundred impacted lower third molars adjacent to the IAN were evaluated. These were divided into four classification groups according to preoperative cone beam computed tomography (CBCT) findings: AR, apical region; LT, lateral region of the tapered root; LE, lateral region of the enlarged root; AE, adjacent to the enlarged root. All teeth were dislocated along the long axis or arc of the root by tooth sectioning technique and extracted by a single surgeon. The primary outcome variable was postoperative neurosensory impairment of the IAN. The χ2 test was used to evaluate differences in postoperative IAN injury between the classifications. Logistic regression analysis was used to evaluate the risk factors for postoperative IAN injury. The overall incidence of postoperative IAN injury was 7%. Specifically, most injuries involved classification AE (AE 36%, LE 8.6%, LT 3.6%, AR 0%), and the difference was statistically significant (P< 0.05). Logistic regression showed that classification AE was the only risk factor for postoperative IAN injury (P< 0.001). According to preoperative CBCT, the risk of postoperative IAN injury is higher when the IAN is adjacent to the enlarged part of the root.

Background and objective: Accurate understanding of the anatomy of the inferior alveolar nerve (IAN) and its relation with anatomical landmarks of mandibular molar teeth can reduce the risk of unwanted injuries to the IAN during implant placement. Methods: 44 CBCTs of patients,who have been reffered to the private oral and maxillofacial radiology center, were examined by a radiologist on the axial, sagittal and coronal planes. Then, the distances between mandibular canal and buccal cortex (BN) and lingual cortex (LN), buccolingual width of the mandibular canal (BL), and the distances between the canal and apex of the first molar (M1N) and second molar of mandible (M2N) were obtained from cross-sectional images. Data were analyzed using SPSS17 software and Kolmogorov-smirnov and Mann-whitney test. Results: 21 males and 23 females aged 20 to 50 years old (mean age: 37.8±7.52) were examined. The mean intervals in the regions of first molar in the right and left sides were BN: 4.03,4.06 mm, LN: 2.10,2.58 mm, BL: 2.20,2.20 mm, and M1N: 5.77,5.78 mm and in the second molar region, on the right and left sides were BN: 5.21,5.20 mm, LN: 1.95,1.80 mm and BL: 2.30,2.20 mm and M2N: 3.85,3.55 mm, respectively. There was a significant difference in the mean buccolingual width of mandibular canal in both sides in the region of first molar and left side in the region of second molar between two genders. (P=0.009, P=0.019, P=0.045). Other measurements were not significantly different between two genders (P>0.05). The age range of patients had no effect on any of the distances and measurements (P>0.05). Conclusion: buccolingual width of mandibular canal in both sides in the region of first molar and left side in the region of second molar was associated with gender.

Exodontia is a routine procedure in dental practice. Despite of adequate effort to perform the pro­cedure with proper technique, some mishap may happen when defective or substandard instru­ments are used. This article reports a symptomatic case of lip paresthesia since 1 month who had undergone attempted surgical extraction of third molar in remote dental hospital. On examination there was presence of retained fractured third molar with exodontia instrument tip in inferior alveolar canal and is very uncommon surgical complications and not much reported in literatures. Patient was not aware of the condition till Orthopantomogram (OPG) was done which revealed presence of approximately 1.5 cm instrument tip in inferior alveolar canal. Third molar and in­strument tip were successfully retrieved from canal under local anesthesia. Rarely, instruments breakage may occur during surgical procedures. It is the duty of every operating dental surgeon to check surgical instruments for signs of breakage and be prepared to solve a possible emergency. Retained fragments should be carefully studied prior to attempt of removal.

Background and objectives: The retromolar canal is an anatomical variant that needs consideration in local anesthesia and surgical procedures involving the retromolar area. Complications such as local anesthetic insufficiency, a sensory deficit, hemorrhage and traumatic neuroma may arise in the absence of recognition of these variants. The aim of this study is to determine the prevalence and course of retromolar canal in the Iranian population. Methods: This study is a descriptive cross sectional study. The cross sectional sagittal and three dimensional images from volumetric CBCT. data of 270 patients were reconstructed using on demand imaging analysis software. Retromolar canals were classified into two types according to the courses. The width and location (distance from the third molar) of retromolar canals were evaluated. Results were analyzed with SPSS 20 software and were assessed using the t_test and chi_square test. Results: Retromolar canal was observed in 9/25 % of patients. The mean width of the retromolar foramen was 1/43 mm, and the mean distance from anterior border of retromolar foramen to the distal CEJ of the second molar was 13/33 mm. Conclusion: The prevalence of retromolar canals in the Iranian population was lower than that was reported in previous studies. It can be observed in 9/25 % of Iranian patients. Damage to the retromolar canal may be unavoidable during surgical procedures may result in paresthesia, excessive bleeding, postoperative hematoma, or traumatic neuroma. Therefore, the clinician must pay particular attention to the identification of a retromolar canal by preoperative radiographic examination and additional CBCT scanning is recommended.

Stafne bone cavity (SBC) is a rare mandibular defect, and the diagnosis and management may be confused with the unusual contents and location. This report for the first time presented a case of SBC with a lymph node content. Meanwhile, a rare case of anterior SBC with fatty tissue content is reported. Typical SBCs with salivary glands content are asymptomatic and showed a well-shaped, ovoid, radiolucent image in the posterior mandible below the inferior alveolar canal in panoramic radiograph. The case of SBC with a lymph node content underwent surgical operation, and definite diagnosis is confirmed by histopathological examination. The case of anterior SBC with fatty tissue content is clarified by MRI confirmed the presence of the fatty tissue and avoided surgical exploration. Surgical interventions would be an unnecessary option in the management of SBC except for the doubtful cases or concomitant other pathologies. Keywords: Stafne bone cavity, Lingual mandibular bone defect, Lymph node, Fatty tissue, Anterior

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. Saudi Med J 2019; Vol. 40 (2): 189-194 doi: 10.15537/smj.2019.2.23602 How to cite this article: Aljarbou FA, Aldosimani M, Althumairy RI, Alhezam AA, Aldawsari AI. 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. Saudi Med J . 2019 Feb;40(2):189-194. doi: 10.15537/smj.2019.2.23602

Context: Relation of inferior alveolar nerve to the impacted mandibular third molars (IMTMs). Aims: The aim of this study was to assess the reliability of seven specific radiographic signs of mandibular third molar root that are observed on orthopantomography (OPG) and to predict the proximity and the absence of corticalization between the mandibular canal and IMTM root on cone-beam computed tomography (CBCT) images. Settings and Design: The present study was conducted in the Department of Oral and Maxillofacial Surgery, Raja Rajeswari Dental College and Hospital. Subjects and Methods: Data set of 30 panoramic images was retrieved between the year of 2015 and 2016 indicated for extraction of lower third molars. The sample consisted of 30 individuals, who underwent preoperative radiographic evaluation before the extraction of impacted mandibular third molars (IMTM). Patients aged above 18 years with any of the seven specific signs observed on the panoramic radiograph which includes darkening, deflection, narrowing of roots, bifid root apex, diversion, narrowing of canal and interruption in the white line of the canal were included in the study. If any of the above mentioned seven specific sign were present, the patient was subjected to CBCT. On the CBCT images, the canal was traced in three planes. The acquired images were assessed for the presence or absence of corticalization. Statistical Analysis Used: Descriptive and inferential statistical analyses were used. Proportions were compared using the Chi-square test and Student's t-test. Results: Among the 4 subjects, diagnosed with an absence of corticalization, patients with isolated darkening of root P = 0.001 and patients with isolated interruption in white line P = 0.69. Patients with darkening of root in association with interruption in white lines on OPG showed the absence of corticalization on CBCT findings P = 0.001, respectively. Conclusions: This study showed the poor reliability of radiographic signs seen on OPG on predicting the proximity of third mandibular root with mandibular canal related to CBCT finding. Four were diagnosed with the absence of corticalization in CBCT findings.

Background: The aim of this study was to determine the distance between the impacted mandibular third molar (IMTM) and the inferior alveolar canal (IAC) at different reference points through panoramic radiographs and cone beam computed tomography (CBCT). Methods: A total of 45 male and 45 female patients with bilateral IMTM at a mean age of 27 years were recruited for this study. With the aid of panaromic radiographs and CBCT, the mandible width, the buccal bone width, IAC width, the lingual bone width, IAC height, the alveolar bone height, and the distance from the lowest part of the IMTM to the superior border of the canal were measured. Statistical analysis was done with independent samples t -test and Mann-Whitney U test for finding the difference between genders. Paired t -test and Wilcoxon signed-rank test were used for comparing both sides at P value = 0.05. Results: The mandible width, IAC width, and IAC height were different between male and female patients. The IMTM roots displayed intimate contact with the IAC in 96.67% of the cases. The location of the IAC was mostly lingual in both genders. The diameter of the IAC was significant larger in men compared to in the women in terms of width and height. Conclusions: This study is useful for the dental surgeon to avoid or prevent postoperative numbness or pain, because the awareness of the common location of the IAC and its approximation with the IMTM roots could allow a more cautious and precise approach during IMTM intervention. J Clin Med Res. 2019;11(5):353-359 doi: https://doi.org/10.14740/jocmr3794

Traditional surgical approaches to the inferior alveolar nerve (IAN) pose a technical challenge and risk iatrogenic damage to healthy, uninvolved nerve tissue. The use of computer-assisted virtual surgical planning and fabrication of surgical guides has shown efficacy in various craniomaxillofacial surgical procedures, and may provide greater precision in accessing the inferior alveolar canal and allow for a more conservative approach. The addition of a depth control feature to a tooth-borne and bone-borne surgical guide, with the use of a standard contra-angle handpiece, provides safe and efficient access for IAN repair. This report describes this novel technique involving a guided transoral approach to the IAN for excision of a neurofibroma of the inferior alveolar nerve, with immediate peripheral nerve allograft IAN reconstruction.

Inferior alveolar nerve (IAN) entrapment in third molar (M3) roots bears a significant risk for nerve injury. The aim of this study was to identify specific panoramic radiographic (PR) signs that can reliably identify IAN entrapment (IANE) root conformations. In a retrospective case-control study, 10 IANE and 218 non-IANE third molar risk cases were examined by PR and CBCT. The collected data included “classic” specific high-risk panoramic signs, number of M3 roots, extent of inferior alveolar canal (IAC)−root tip overlap, rotated position of M3 and impaction pattern. After bivariate analysis, sensitivity, specificity, positive and negative predictive values, positive likelihood ratios (LR+) and accuracy (area under the curve [AUC]) were calculated for the most significant predictive variables. Interruption of both cortical lines (LR+: 43.6; AUC: 96.0%) and upward diversion of the IAC (LR+: 36.3; AUC: 96.5%) were the most accurate single signs indicating IANE. Upward diversion combined with root darkening and interruption of the IAC (AUC: 97.4%) and the combination of darkening with interruption and with a rotated M3 (LR+:130.8; AUC: 97.8%) were the most accurate combinations predicting IANE. IANE may be correctly filtered with PR when focusing on the signs of upward diversion, darkening, interruption and rotated M3 position, especially in cases involving their multiple (≥3) presence. CBCT evaluation is highly recommended in these cases before partial and total tooth removals.

Introduction: Although the inferior alveolar nerve had been described as a single entity that travels through the mandibular canal and leaves it through the mental foramen directly giving rise to mental nerve, presence of mental loop was reported. Improper identification of mental loop led to increasing the incidence of nerve injury during surgical procedures especially implant placement. Objective of the study: The purpose of this study was to assess mental loop and its length among a sample of Egyptians, using cone beam computed tomography (CBCT). Materials and Methods: Two hundred and sixty-seven CBCTs were collected in which one hundred were males and one hundred and sixty-seven were females, then evaluated for the presence of the mental loop. The length of the loop was measured on reconstructed panoramic views of CBCT using on demand software. Results: Mental loop was present in one hundred and nine patients (40% of the patients), 63 females and 46 males. The minimum length observed was 2.27 mm. while the maximum length was 7.18mm and the mean length was 4.36±.96mm. There was no significant difference between males and females. Conclusions: High prevalence of mental loop was detected in Egyptians. Based on this finding proper identification of mental loop by the method explained in this study prior to surgical planning is essential. Keywords: Anatomical variant, CBCT, inferior alveolar canal, mental nerve loop

Background and Objectives. Surgical extraction of mandibular third molars (3rd M) may cause inferior alveolar nerve injury (IANI), whereas in coronectomy the crowns of 3rd M are removed, keeping the roots intact to avoid IANI. This study aims to review the literature which evaluated coronectomy effectiveness as an alternative for surgical extraction of 3rd M that have a high risk of trauma to the inferior alveolar canal. A computerized literature search was conducted on the databases PubMed, SCOPUS, and ScienceDirect to gather information regarding the coronectomy procedure from inception till June 5, 2020. A total of 97 articles were identified, and seven studies were finally included for conducting qualitative analysis: 3 randomized clinical trials and 4 clinical controlled trials. Cochrane Collaboration’s tool was used for assessing risk of bias. Coronectomy procedures were performed on 15–171 teeth. In the control group, extraction procedures were done on 15–178 teeth. Results. No study reported permanent inferior alveolar nerve injury (p-IANI) regarding coronectomy; however, transient inferior alveolar nerve injury (t-IANI) was reported in 0–2.20% of successful coronectomy and 0–8% of failed coronectomy. Postextraction t-IANI ranged from 0% to 16.66% while p-IANI from 0% to 3.63%. In 5 studies, root migration occurred in 2% to 85.3% of cases and the distance rate was 2.33–3.43 mm at 6 months postoperatively; then the migration gradually decreased and stopped at 12 months. Conclusion. This systematic review revealed that coronectomy is an efficient alternative for the management of impacted 3rd M with a high risk of IANI. Patients who got antibiotics postcoronectomy procedures had lower infection rates than those who did not receive antibiotic therapy. We recommend further research on coronectomy with longer follow-up periods to assess the retained roots’ long-term outcomes and to assess the effect of antibiotics administration on postcoronectomy infection rate. This systematic review is registered under number CRD42020198394.

Ectopic lower third molar is an uncommon condition, and its etiology remains unclear. The main approach used for its surgical removal is the intraoral one, but there are cases in which this may not be the best option. When the lower third molar is located below the lower alveolar canal or when it is close to the lower edge of the jaw, the most recommended approach is the extraoral one. The critical issues related to the extraoral approach are the possibility of damaging anatomical structures such as marginal mandibular branch of the facial nerve (craniofacial nerve VII), facial artery and vein, and submental artery. This complication can occur during incision and dissection of the superficial layers or during osteotomy with rotating instruments.This paper reports a case of extraction of ectopic lower third molar using a minimally invasive extraoral approach combined with piezoelectric surgery in order to prevent intraoperative injury of anatomical structures.

Purpose Cone-beam computed tomography (CBCT) offers the advantage of a 3-dimensional representation of the anatomic relationship of the mandibular third molar tooth and the inferior alveolar canal (IAC), as compared to a panoramic radiograph. We hypothesized that a novel method of categorizing the degrees of compression of the IAC were reliable predictors for postoperative nerve injuries. Methods We conducted a retrospective analysis of the outcomes in third molar surgery for patients who obtained a CBCT scan in additional to a plain film radiograph over a 12 months period and underwent surgical removal of their mandibular third molars; 257 consecutive patients were identified, and 416 mandibular third molars were surgically removed. Results Patients who had severe compression of the inferior alveolar canal (IAC) on CBCT imaging had a significantly increased risk of a postoperative IAN injury (P = .0068, OR = 3.47, 95% CI: 1.40 to 8.54) and accounted for 52.17% of all IAN injuries. Ninety-one percent of all cases of postoperative nerve injury occurred in female patients. The mean age of patients with a postoperative IAN injury (30.2 years) was significantly higher than those without injury 26.0 years; (P = .016, 95%CI: 25.11 to 33.80) CONCLUSIONS: In addition to patient factors, assessment of the degree of compression on a preoperative CBCT image is a useful tool for predicting outcomes in mandibular third molar surgery. In cases of severe compression of the IAC, patients are at a significantly increased risk of postoperative IAN injury.

Aim Understanding the mental foramen (MF) position and prevalence and location of the anterior loop (AL) is important during clinical and surgical procedures close to the mental foramen to avoid damage to the neurovascular bundle. The current study was done to determine the location of the MF, its distance from the inferior border of the mandible, and prevalence of AL in Egyptian population using cone beam computed tomography (CBCT). Methods A retrospective analysis of CBCT images was done in this study. Images of Egyptian patients who have already been subjected to CBCT examination as part of their dental diagnosis and/or treatment planning were included according to the proposed eligibility criteria. Results This study showed that the most common location of the MF (43.8% on the left side and 67.9% on the right side) is located below the apex of the second premolar. The mean size of mental foramen showed a height of 3.32 mm in females, 3.60 mm in males, and a width of 3.41 mm in females and 3.59 mm in males. The mean value of distance from inferior border was 10.08 mm in females and 10.55 mm in males. Fifty-five percent of the cases showed presence of anterior loop. Conclusion These results are consistent with similar radiographic studies regarding size and location of MF and distances between MF and adjacent anatomic structures. The most common position of the MF is below the 2nd premolar. AL was found in more than half of the cases examined.

Introduction The mandibular canal, as it was formerly named in Terminologia Anatomica (TA), has also been called the inferior alveolar (nerve) canal in many scientific publications. This study was conducted to investigate how these terms have been understood in different regions and different areas of expertise and to discuss the appropriate future application of the term "mandibular canal." Methods A literature search was conducted using PubMed, and articles using different terms for this structure were classified into two groups, inferior alveolar canal/inferior alveolar nerve canal (IAC/IANC) and the mandibular canal (MC). The 50 most recent articles in each group were included. Publication year, journal title, country of the first author, and affiliation of all authors were recorded in both groups for all 100 articles. Results There was a significant difference between the IAC/IANC and MC groups in the numbers of anatomy journals, other journals, and anatomy affiliations. Turkey published most frequently with a total of 15 articles, followed by Iran with 10 articles, and China/India/United States with seven each. When the six countries of the first author that had three or more publications in each group were compared, only Turkey appeared in both groups; otherwise, different countries were in the two groups. Conclusions Based on the results of this analysis, and considering that the tentative new term "inferior alveolar foramen" is used in the latest TA, we suggest that the mandibular canal should be renamed the "inferior alveolar canal."

The purpose of this study was to assess the pre- and postoperative position and dimensions of the inferior alveolar canal (IAC) following sagittal split osteotomy (SSO) and identify any association with postoperative neurosensory deficit (NSD) at 1 year. This retrospective cohort study enrolled consecutive patients who had SSO performed to correct skeletal malocclusion. The pre- and postoperative cone beam computed tomography data were superimposed to visualize differences in IAC position and dimensions. Subjective and objective neurosensory tests were used to determine NSD in the inferior alveolar nerve distribution. A total of 20 subjects were included. The preoperative distance from the lateral cortex of the IAC to the inner aspect of the lateral cortex of the mandible was significantly greater in sides with NSD when compared to sides without NSD (P = 0.01). A significantly greater reduction in the postoperative distance measurement was seen in sides with NSD when compared to sides without NSD (P = 0.01). The magnitude of mandibular movement was significantly increased in sides with NSD (P = 0.02). The preoperative location of the IAC, as well as certain changes in the mediolateral and vertical positions as a result of SSO, are risk factors for postoperative NSD.

Objective To present for the first time in the north-western Spanish osteological record prevalence data on Stafne’s bone defect, to compare the results with those reported by other studies, and to increase the dataset for future inter-population comparisons. Material In all, 143 complete adult mandibles recovered from two necropolises were analyzed (n = 118, San Juan Bautista of Guardo, Palencia province, 16th-19th centuries; n = 25, Plaza del Grano, city of Leon, 12th-15th centuries). Methods Differential diagnosis of the lesions was made through macroscopic and Computed Tomography (CT) analyses. Results Four mandibles (n = 3, Guardo, Palencia; n = 1, Leon) presented bone cavities on the lingual aspect of the mandible below the mylohyoid channel, between the first molar and the angle of the mandible. CT scan showed unilateral well-defined unilocular oval/round concavities in the lingual mandibular cortex below the inferior alveolar canal. Neither the macroscopic nor the radiological characteristics are compatible with inflammatory or malignant pathology, favoring instead a diagnosis of Stafne’s bone defect. Conclusions Four cases of Stafne’s defects are added to the bioarchaeological inventory. The calculated prevalence is 2.54% for San Juan Bautista and 4% for Plaza del Grano, values in close agreement to those presented in other osteoarchaeological studies. Significance The identification of all examples of Stafne’s bone defects in past populations will contribute to elucidate which factors may be responsible for this trait’s cultural, ecological, temporal, and geographical patterning. Limitations The skeletal samples are relatively small. Suggestions for Further Research In future investigations of Stafne’s bone defects, CT analysis of dry bone specimens is recommended, whenever possible.

The aim of this ex vivo study was to compare the diagnostic performances of panoramic radiography and cone beam computerized tomography (CBCT) in detecting implant-related injuries of the inferior alveolar canal. Monocortical bone windows were created in 60 fresh sheep hemimandibles, the inferior alveolar canals were revealed and 120 dental implants were inserted. Three types of injuries, described as pilot drill damage (PDRILL), collapsing of the superior border of the canal (COLL), penetration of the implant tip into the canal (PENET) and one control group, were simulated. Standard (PANO) and dentition mode panoramic (PANO-DENT) images as well as CBCT data presented as multiplanar reconstruction (MPR) and cross-sectional (CROSS) views were evaluated by 6 observers who had also expressed their level of confidence to their final diagnosis. Intra- and interobserver agreement scores were rated good. The area under the curve (AUC) values and the confidence scores for CROSS and multiplanar reformation (MPR) views were both significantly higher than those of PANO and PANO-DENT (P < .05 for each) in PDRILL group. In COLL group, observers showed less confidence to PANO and PANO-DENT compared to CROSS and MPR techniques (P < .05 for each). No other significant differences were found. Within the limits of this experimental study, it can be suggested that the standard and dentition modes of panoramic radiography can be as effective as CBCT in the detection of penetrating and collapsing injuries, but multiplanar and cross-sectional views of the CBCT are more accurate than panoramic radiography in the detection of pilot drill injuries in sheep mandible.

Placement of dental implants in the posterior mandibular alveolar ridges may become a challenging procedure because of limited bone height between the crest of the ridge and the inferior alveolar canal. The aim of this study was to introduce an innovative, less invasive, highly accurate, and easy surgical technique of inferior alveolar nerve lateralization in the posterior deficient mandible using a special customized 3-dimensional–printed surgical guide to enhance the bone height for implant placement. This case series study included 7 patients with unilateral edentulous mandibular alveolar ridges. Customized surgical guides were manufactured using fused deposition modeling technology to accurately place a rectangular window to uncover the canal and also for immediate placement of dental implants in all cases. The results of this limited study provided information on an innovative technique that decreased intraoperative time and demonstrated decreased risks for (1) inferior alveolar nerve injury and (2) postoperative nerve dysfunction.

الملخص: أهداف البحث: هدفت هذه الدراسة إلى التحقق من دقة علامات الخطورة في التصوير الاشعاعي البانورامي من خلال الكشف عن وجود أو عدم وجود التكون القشري بين ضرس الرحى السفلي الثالث المدفون والقناة السنخية السفلية في الأشعة المقطعية المخروطية. طرق البحث: دَرست هذه الدراسة الاسترجاعية ٢١٠ ضرسا فكيا سفليا ثالثا منغرسا من ١٣٥ مريضا (بأعمار من ١٧ -٥١ سنة) والذين أظهروا واحدا أو أكثر من علامات الخطر البانورامية السبع المقترحة للتعرض العصبي السنخي السفلي. أُحيل هؤلاء المرضى للفحص بالأشعة المقطعية المخروطية. واستُخدمت الصور ثلاثية الأبعاد لتقييم موقع القناة بالنسبة للضرس الثالث، وقرب القناة من الضرس الثالث وزاوية ميول الضرس الثالث. وقورنت نتائج الأشعة البانورامية والأشعة المقطعية المخروطية. النتائج: كانت نتائج الأشعة البانورامية عندما بينت انقطاع جدار القناة السنخية السفلية، سواء كان ذلك مقترنا أو غير مقترن بإحدى هذه العلامات؛ سواد جذور الضروس الثالثة، وضيق القناة، وانحراف القناة، وبخاصة سواد الجذور، وضيق القناة كان مرتبطا ارتباطا ذا قيمة إحصائية بالاتصال المباشر بين قناة الفك السفلي والأضراس الثالثة المنغرسة في الأشعة المقطعية المخروطية. الاستنتاجات: يُوصى بعمل الأشعة المقطعية المخروطية قبل العملية في الحالات التي تبين سواد الجذور، أو ضيق القناة، أو التي تبين الانقطاع والضيق معا، أو انحراف أو سواد الجذور معا في الأشعة البانورامية. وقد قيمت هذه الدراسة علاقة الخطورة بين العصب السنخي السفلي والأضراس الثالثة في الفك السفلي المنغرسة وآلية الحد من حدوث إصابة ما بعد الجراحة في العصب السنخي السفلي. Abstract: Objectives: This study aimed to validate the accuracy of panoramic radiographic risk signs through detection of presence or absence of corticalization between an impacted mandibular third molar and the inferior alveolar canal on cone beam computed tomography (CBCT). Methods: This retrospective study analyzed 210 impacted mandibular third molars from 135 patients (aged 17–51 years) who showed one or more of the seven previously established panoramic radiographic risk signs of inferior alveolar nerve exposure. These patients were referred for CBCT examination. Three-dimensional images were used to assess the canal position relative to the third molar, the proximity between the canal and third molar, and third molar angulation. The correlation of panoramic findings and CBCT was evaluated using a Chi-square test. Results: Panoramic findings of interruption of inferior alveolar canal wall, isolated or combined with one of these signs (darkening of third molar roots, narrowing of canal, and diversion of canal); darkening of the roots; and narrowing of canal were significantly correlated with direct contact between the inferior alveolar canal and impacted third molars on CBCT (P

Introduction The present study was aimed to identify the radiographic signs between impacted third molar root and inferior alveolar canal (IAC) on cone-beam CT (CBCT) images as risk factors and prognostic predictors associated with inferior alveolar nerve (IAN) damage following tooth removal. Material and methods A retrospective clinical study was performed involving 136 patients with 257 impacted lower third molars from January 2013 to December 2014. The neurosensory function of the lower lip and chin was subjectively evaluated and assessed by neurosensory tests before and after surgery. The preoperative CBCT data were retrieved and analyzed to identify the radiographic signs associated with postoperative IAN injury. Results The overall incidence of IAN injury in our patient cohort was 13.2%. Multiple radiographic features on coronal CBCT images including contact between IAC and root, IAC position relative to root, IAC shape and cortication status were found to be significantly associated with IAN damage (p < 0.05, χ2 test). Furthermore, buccolingual position, teardrop/dumbbell shape and cortication status of IAC were identified as independent prognostic predictors for IAN damage. Conclusions Our findings indicate that radiographic signs including direct contact between IAC and root, buccal/lingual IAC position relative to root, teardrop/dumbbell shape and cortication absence of the IAC on presurgical CBCT images are associated with high risk of IAN injury and postoperative neurosensory disturbance.

Context: Choosing an imaging source, which provides minimum radiation exposure to the patient, to facilitate surgical removal of impacted mandibular third molars (MTMs), thereby avoiding unwanted neurological complications. Aim: The aim of the study was to assess the efficacy of digital volume tomography (DVT) in evaluating the position of inferior alveolar canal (IAC) in relation to impacted MTMs and comparing it with conventional radiography (CR) in a subset of the Indian population. Materials and Methods: Four experienced observers assessed two groups: 33 DVT and 33 CR images, for the position of root-tips of impacted MTM in the proximity to IAC, in both vertical and horizontal planes. The diagnostic information was compared in both the groups. Statistical Analysis: Chi-square test, Mann–Whitney U-test, and Kappa statistics were used. Results: Comparison between DVT and CR revealed no statistically significant variation in assessing relationship in the vertical plane. There was, however, a significant difference between the groups, while comparing the diagnostic information for the horizontal dimension, for both the mesial and the distal roots, with an advantage for DVT (P < 0.05 for both mesial and distal roots). Conclusion: DVT is highly accurate in predicting neurovascular bundle exposure. It is indispensable for preoperative evaluation of impacted MTM.

Background and objective: Extraction of an impacted mandibular third lower molar tooth is one of the common surgical procedures that may lead to the damage of inferior alveolar nerve due to roots proximity to the mandibular canal. This study aimed to know the relative relationship and proximity of the mandibular third molar roots to the inferior alveolar canal in relation to gender, age, depth of impaction, relation with ramus, and type of angulation of the impacted tooth in Kurdistan population. Methods: A sample of 366 digital panoramic radiographs of patients with impacted mandibular third molar was studied. Panoramic radiographic signs images were evaluated for the presence of root contact with the superior border of the mandibular canal, darkening of the roots apex, deflected roots, narrow root, superimposition of the canal, interruption of the white line, diversion of the inferior alveolar canal, and narrowing of the inferior alveolar canal. The depths of impaction, relation with ramus, and type of angulation were also studied. Results: Significant relation of the proximity of the mandibular third molar roots to the inferior alveolar canal with the gender (P = 0.001) and age (P

The extraction of mandibular third molars can lead to injury to the inferior alveolar nerve. Hence, it is important to assess the proximity of the root to the inferior alveolar canal before extraction. The classification system of Pell and Gregory and the Winter classification are commonly used to evaluate the positional relationship of the third molar based on radiographs. This retrospective study involving 105 mandibular third molars was performed to assess whether these systems reflect the proximity of the root to the canal (based on computed tomography images), and to identify risk factors for nerve injury. Regarding the prediction of computed tomography-verified canal invasion, the sensitivity, specificity, and positive and negative predictive values were high for each Pell and Gregory category when there was radiographic evidence. The mean distance of invasion was significantly greater in class III than in class I. However, there were no significant differences between the Winter inclination categories. The mean distance differed significantly between a horizontal inclination angle to the buccal side of >5° and an angle of ≤5°. Thus, a horizontal inclination angle >5° represents a novel risk factor for nerve injury.

A retrospective cohort study was performed to assess the clinical usefulness of combination assessment using computed tomography (CT) images in patients undergoing third molar extraction. This study included 85 patients (124 extraction sites). The relationship between cortication status, buccolingual position, and shape of the inferior alveolar canal (IAC) on CT images and the incidence of inferior alveolar nerve (IAN) injury after third molar extraction was evaluated. IAN injury was observed at eight of the 124 sites (6.5%), and in five of 19 sites (26.3%) in which cortication was absent+the IAC had a lingual position+the IAC had a dumbbell shape. Significant relationships were found between IAN injury and the three IAC factors (cortication status, IAC position, and IAC shape; P=0.0001). In patients with the three IAC factors, logistic regression analysis indicated a strong association between these factors and IAN injury (P=0.007). An absence of cortication, a lingually positioned IAC, and a dumbbell-shaped IAC are considered to indicate a high risk of IAN injury according to the logistic regression analysis (P=0.007). These results suggest that a combined assessment of these three IAC factors could be useful for the improved prediction of IAN injury.

The aim of this in vitro study was to investigate temperature increases in the inferior alveolar canal (IAC), when different bone preparation methods approximate and penetrate the IAC.In pig mandible, buccal bone removals were performed until the neurovascular bundle became visible. Temperatures were registered with thermocouple probes and with infrared thermometer. Preparations were performed with diamond drills (DD), tungsten carbide drills (TCD), piezoelectric diamond sphere (PT_D) and saw (PT_S) tips, and a combined preparation method was also performed whereby the superficial three-fourths of the bone was removed with TCD and the deepest one-fourth of the bone with PT_D (TCD + PT_D_7 °C) or PT_S (TCD + PT_S_7 °C), using cooled irrigation (7 °C).Preparations using room temperature irrigation caused significantly less heat on the bone surface than in the IAC. Piezosurgery in the IAC produced significantly higher temperatures (13 °C) than the drills (4 °C). Heat productions of the piezoelectric tips were reduced significantly by applying the combined bone removal methods. The speed of PT_S and TCD + PT_S_7 °C were comparable to the speed of TCD, whereas TCD + PT_D_7 °C was found to be significantly slower.The speed of piezosurgery is comparable to that of the drills; however, it produces the highest, potentially nerve-harming temperatures. To eliminate the heat consequences during piezosurgery in the IAC, the use of cooled irrigation at 7 °C and predrilling is recommended.

The knowledge and application of anatomy is essential for any professional involved in the evaluation, diagnosis, prognosis and treatment of the different alterations of the maxillofacial complex. The ignorance of the anatomical relationships of the inferior alveolar duct in the different surgical procedures can lacerate, compress or stretch the nerve generating lesions such as neuropraxia, axonotmesis and neurotmesis. The objective of this review is to describe the variations of the inferior alveolar duct course reported in the literature. There are 6 possible categories in which the variations of the CAI can be classified: 4 views in panoramic radiographs (two dimensions) and 2 views in computerized axial tomography (three dimensions). The inferior alveolar duct presents a great variability between patients and populations, which accentuate the product of tooth loss and alveolar reabsorption. Computed tomography of conic beam is the most suitable method for its evaluation.

/ Montanero-Fernandez, Jesus / Sheridan, Rachel A. / Wang, Hom-Lay / Wang, Feng Purpose: The aim of this study was to investigate the influence of posterior mandibular dimensions (height and width at various levels) on alveolar bone microarchitecture using microcomputed tomography (micro- CT). Materials and Methods: Partially edentulous subjects with one missing molar were included in the study. A bone core biopsy was performed at the site of planned implant surgery. For each patient, alveolar morphologic and architectural characteristics were analyzed using cone beam computed tomography (CBCT) and micro-CT imaging. Two parameters for height (apicocoronal residual height [RH] and residual ridge from inferior alveolar canal [RHN]) and three for buccolingual width (residual width at 5 mm [RW1], at 10 mm [RW2], and at 15 mm [RW3]) were determined using CBCT. Additionally, 10 parameters were obtained from micro-CT to determine microarchitecture. Pearson product-moment correlation coefficients were calculated to examine the correlation between the morphologic and microarchitectural variables. Results: Significant positive correlations (P < .05) were found between RH and bone volumetric fraction (BV/TV) (rs = 0.34) and trabecular thickness (Tb.Th) (rs = 0.45). A significant negative correlation was found between RH and the bone-specific surface (BS/BV) (rs = -0.34). A strong significant negative correlation was found between trabecular spacing (Tb.Sp) and RW1 (rs = -0.42). None of the other variables reached statistical significance. Conclusion: Posterior mandibular dimensions may affect bony architectural characteristics.

Cone-beam-computed-tomography (CBCT) has been useful in providing insights of relevant anatomy prior to surgical procedures, including the assessment of the proximity of impacted mandibular-third-molar to the inferior-alveolar-canal (IAC). It is important to understand the reliability of conventional panoramic-radiograph in the assessment of this criterion since it is more commonly used as first line radiographic approach due to its availability and lower radiation dose. This study aimed to investigate the reliability of conventional panoramic-radiograph in the evaluation of the proximity of impacted mandibular-third-molar root tip to the IAC by correlating the results with CBCT. A total of 65 root tips of impacted mandibular-third-molars that had both panoramic radiographs and CBCT images were included in this retrospective study. Two trained observers participated in all image evaluations. A prepared standard 1 cm ruler was used to measure the proximity of the third-molar root apices to the IACs. Measurements recorded in this study were categorized into positive (root apex above a roof of IAC), zero (root apex was superimposed on IAC) and negative (root apex below a roof of IAC). Data analysis was carried out using student t-test. In this study, both observers recorded statistically significant differences in the measurement between third-molars root apices and the IAC from panoramic radiographs and CBCT images. The low reliability of panoramic radiograph to assess the vertical proximity between these two anatomical structures suggests the importance of additional assessment with CBCT in cases where panoramic radiograph shows superimposition of the third molar root on the roof of the canal and presence of root below the roof of the IAC.

Purpose Cone-beam computed tomography (CBCT) is commonly requested before dental implant treatment for the anatomic assessment of the inferior alveolar canal (IAC) to prevent its neurovascular content from being traumatized. CBCT images can be saved in different types of resolutions and bit depths; these parameters may significantly affect the diagnostic accuracy of images. This study aimed to assess the effect of resolution and bit depth on IAC visualization on exported mandibular CBCT images. Materials and Methods Forty-one mandibular CBCT images of differing image resolutions and voxel sizes (0.16, 0.32, and 0.48 mm) and differing bit depths (12 and 15) were exported from a software program as a single file. Two observers evaluated the cross-sectional images in terms of IAC visibility using a 3-point scale (good, moderate, and poor). Disagreements were resolved by including a third observer, and the highest agreement was recorded. Results Study interobserver agreement was acceptable (84.2%) for IAC observation. The percentage of IAC observation was from 84.1 to 100% with the 12- and 15-bit depths, with a constant image resolution of 0.16 and 0.32 mm, respectively. A significant difference (from 19.5 to 48.8%) was noted between the 2 bit depths in the percentage of good IAC visualization with a constant resolution of 0.48 mm. Reduction in the image resolution to 0.48 mm showed a significant difference (19.5 to 100%) between the 12- and 15-bit depths in good IAC visualization. Conclusions Exporting the mandibular CBCT images with 0.32 mm of resolution and a 12-bit depth will produce good and moderate radiographic IAC observation with the benefit of a smaller file size.

WOS: 000519600000012 PubMed: 31983633 Objective. To assess the reliability of radiographic signs of the relationship between impacted mandibular third molars (IMTMs) and the inferior alveolar canal (IAC), and the vertical relationship between IMTM and IAC on panoramic radiographs (PRs) as risk indicators for IAC exposure during extraction. Study Design. Seven radiographic signs regarding the appearance of roots and the IAC were assessed as present or absent on PRs. The vertical relationship between IMTM and the IAC was divided into 3 levels. The correlation between radiographic data and IAC exposure during extraction was analyzed by using chi(2) statistics and logistic regression analysis. Results. In total, 198 IMTMs were examined. In 46 cases (23.2%), the IAC was exposed during extraction. Four radiographic signs-darkening of the root, narrowing of the root, narrowing of the IAC, and diversion of the IAC-were associated with IAC exposure (P

Avascular osseo-necrosis is one of the rare complications that has never been reported in pediatric mandibular distraction. However extensive periosteal stripping, developing tooth buds and aberrations related to the inferior alveolar canal in malformed syndromic mandible may lead to compromised vascularity to the osteotomised segments leading to avascular necrosis after monofocal mandibular distraction. The aim of the current case report is to describe this rare complication after pediatric MMDO and discuss in detail the possible etio-pathologic mechanisms and provide an insight for the management strategies.

Purpose: The aim of this retrospective study is to determine the radiological features of keratocystic odontogenic tumors (KCOT) using cone-beam computed tomography (CBCT).Materials and methods: CBCT images of 28 patients who had histopathologically-confirmed KCOT were retrospectively reviewed from the archives of the Department of Dentomaxillofacial Radiology, Gazi University Faculty of Dentistry. The location and size of KCOT, cortical expansion, cortical perforation, relation with the impacted teeth, and the impact on the mandibular canal were evaluated.Results: The mean age of patients at initial diagnosis was 34.5 years. Patients with an impacted tooth were significantly younger than those without an impacted tooth (p < 0.05). Among KCOTs, 21% were localized in the maxilla whereas 79% were found in the mandible. The lesions localized in the mandible were mostly found in the retromolar-ramus region. Of these patients, 93% had cortical expansion and 75% had bone perforation. Of the 22 mandibular lesions, 20 were in close proximity of the mandibular canal and 18 (90%) of these lesions had caused destruction in the mandibular canal.Conclusion: KCOTs exhibit their aggressive nature in the jaw bone. CBCT is a useful radiological imaging method to examine the radiologic characteristics of KCOTs such as bone destruction and their spatial relations with the neighboring anatomic structures.

The aim of this study was to use cone-beam computerized tomography (CBCT) images of patients to assess the prevalence of different types, especially anterior loop, of the mental portion of the inferior alveolar canal and to evaluate the anterior loop lengths. CBCT images of 494 patients providing inclusion criteria were examined by 2 oral radiologists. Sagittal, axial, and multiplanar reformatted images were used to detect the type of mental portion of the inferior alveolar canal. The anterior loop length was measured in the respective sections of each CBCT image. Statistical analysis was performed using SPSS v. 15, and t tests were used for statistical analysis. Of the 494 patients, 217 anterior loops were detected in 141 (28.5%) patients. The mean anterior loop lengths for the right side and the left side were 2.19 ± 1 mm and 2.08 ± 0.89 mm, respectively. The difference between males and females in the mean anterior loop length was statistically significant for both sides (Right: P < .05; Left: P < .05). A presurgical CBCT image examination is necessary prior to implant insertion to reveal the presence of anterior loop and to detect actual anterior loop length.

BACKGROUND: The frequent anatomical variations of the inferior alveolar nerve (IAN) course should be considered prior to any treatment in this area. The aim of this study was to evaluate the course of the inferior alveolar canal (IAC) as it appears in the archived CBCT images of the mandible. MATERIAL AND METHODS: This cross- sectional study evaluated a sample of 156 CBCT examinations. The pattern of the IAC was evaluated and the prevalence of different patterns according to age and gender were recorded. In order to find the frequency of mandibular canal type among different ages, the patients were put into the three age groups (20-29, 30-44 and 45-59).The data were analyzed using Chi-square test and the significance level was set as p≤.05. RESULTS: Out of 156 patients, 52 canals was straight type, 52 had Catenary type and 52 of them were presented with Progressive descending type. There was not statistically significant difference between two genders (Pv=0.092). According to the type of the IAC course, there was a not statistically significant difference between the three age groups (Pv=0.32). CONCLUSIONS: Cone beam computed tomography is a useful method for precise assessment of the IAC course.

Aims: To determine the real not radio graphical proximity of mandibular third molar tooth to the inferior dental canal (IDC) using panoramic radiograph. Materials and Methods: 144 mandibular third molars were evaluated by panoramic radiography. The teeth were grouped into erupted vs. un erupted further subdivided by tooth angulations. The real distance from the most inferior aspect of the mandibular third molar tooth to the superior border of the inferior alveolar canal (IAC) was calculated regarding to the reference object used. Descriptive statistics were performed as well as a t test was performed to compare erupted and unerupted teeth, and ANOVA was used to determine a significant difference where exists based upon tooth angulations. In addition, intra observer analysis was done to ensure the standardization of the radiologist interpretation. Results: The mean distance from erupted mandibular third molar teeth to the inferior alveolar canal was 0.23mm. This distance was significantly different from unerupted teeth (P = .000). The mean values for unerupted teeth were negative values which indicated that the apices of all teeth measured was below the superior border of the canal –1.26 mm and as follows: Mesioangular–1.32 mm, vertical – 1.34 mm and –1.04mm for horizontal impactions. Statistically there was no significant positional difference between the impaction groups (P = .835). In general there was a significant difference in third molar position between those age equal and less than 22 years old and those equal and over 23 years old. Conclusions: Unerupted mandibular third molar teeth (mostly vertical impaction) are closer to the inferior alveolar canal than erupted teeth and persons in general of an age equal or less than 23 years old have a closer lower third molar to mandibular canal than other ages and there is no significant relation between this age group and any of impaction types.

Introducción: Las lesiones iatrogénicas del nervio dentario inferior son complicaciones documentadas de diversos procedimientos quirúrgicos en la mandíbula. Debido a ello se justifica una descripción más detallada con referencias morfométricas de dicho conducto, como así también una correlación con imágenes. Materiales y métodos: Se realizó un estudio descriptivo observacional con una muestra de 44 hemimandíbulas secas y 100 tomografías computadas de mandíbulas de pacientes al azar. Se realizaron mediciones del foramen mandibular y mentoniano con respecto a bordes mandibulares. Se hicieron cortes en la rama y el cuerpo con sus respectivas mediciones. Se utilizaron Tomografías Computadas Cone Beam 3D de 100 pacientes las cuales fueron procesadas por el programa Compudent Navigator 3D®. Utilizando este programa se pudieron realizar las mismas mediciones que en los preparados anatómicos, como así también la reconstrucción del conducto. En una segunda etapa se realizó una correlación entre los valores morfométricos del estudio anatómico y se comparó con los estudios por imágenes (TC con reconstrucción 3D Dental Scan). Resultados: Se expresaron en tablas con diversas variables. Discusión: Los textos clásicos de anatomía y los libros de cirugía de la especialidad describen en detalle el recorrido y las relaciones del CAI, y presentan datos morfométricos pero no lo hacen en poblaciones locales. Como conclusión podemos afirmar que, tomando como punto de partida la anatomía y correlacionándola con la imagenologia, podemos llegar a evitar lesiones del nervio alveolar inferior en el transcurso de diversos procedimientos realizados en la mandíbula. Introduction: Iatrogenic inferior alveolar nerve injuries are documented complications of different surgical procedures in the jaw. It should justify a more detailed description with morphometric references of the duct and a correlation with images. Materials and method: A descriptive observational study with a sample of 44 dry hemijaws and 100 CT scans of patients. Measur-ements of the mandibular foramen and mental foramen with respect to jaw edges were made. Cuts in the branch and body were made with their respective measurements. Cone Beam Computed Tomography 3D (CBCT 3D) of 100 patients were processed by the Compudent Navigator 3D® program. The use of this program permited the same measurements done in the cadaveric jaws and the reconstruction of the duct. In a second stage we performed a correlation between the anatomic morphometric values compared with imaging studies (CT Dental Scan with 3D reconstruction) Results: They were shown in tables with different variables. Discussion: The classic texts of Anatomy and surgery books describe in detail the pathway and relations of the duct, and present morphometric data but not in local population. We may conclude that it is possible to avoid injuries of the inferior alveolar nerve during jaw surgery by considering the anatomy and its correlation with images.

Context: Better understanding of the anatomical location and course of the mandibular canal is necessary to avoid damaging inferior alveolar nerve. Aims: The aim of this study was to investigate the buccolingual course of the inferior alveolar canal (IAC) in different mental foramen locations, using cone beam computed tomography. Materials and Methods: Three hundred and twelve hemimandibular images were evaluated in this study. The location of mental foramen in relation to the apices of mandibular premolar and molar teeth were recorded. Nine measurements (in millimeters) were taken at the level of the IAC and posterior mandibular premolar and molar root apices. Relative distances of IAC to buccal and lingual mandibular cortex were calculated for different mental foramen types. Statistical Analysis Used: Data were analyzed by one-way analysis of variance and P < 0.05 was considered to be statistically significant. Results: The distribution of subjects according to the type of mental foramen includes: Type 1 = 50.3% (at the level of second premolar apex), Type 2 = 33% (between the apices of first and second premolars), and Type 3 = 16.7% (between the apices of second premolars and first molars). The buccolingual ratio of the IAC position was statistically significant in different mental foramen types (P = 0.00). Conclusion: The position of IAC was affected by the location of the mental foramen. The direction of IAC gradually changed from lingual to buccal and from posterior to anterior.

Objective The objective was to identify the lowest doses required to detect and measure the position of the inferior alveolar canal (IAC) on multidetector computed tomography (MDCT) images using filtered backprojection (FBP) and sinogram-affirmed iterative reconstructions (SAFIRE) 3 and SAFIRE 5. Study Design Four cadaveric mandibles were imaged using a reference protocol with standard dose and FBP and 3 ultra-low-dose protocols (LD1-LD3), using an MDCT scanner. All test examinations were reconstructed with FBP, SAFIRE 3, and SAFIRE 5. Subjective visibility of the IAC in the images and digital measurements of the height of the ridge above the IAC were recorded from test images and compared with those from the reference image using one-sample t tests, Bland-Altman plots, and linear regression. Results Subjective visibility comparable to the standard protocol was obtained with an 84.6% dose reduction using the LD2 protocol. No statistically significant difference was found between the height measurements from the reference protocol and any of the LD1 and LD2 protocols. The t tests indicated a significant difference between the measurements from the reference and all LD3 test protocols. SAFIRE did not have an advantage over FBP images. Conclusions Significant dose reduction from the reference dose can allow adequate detection and measurements of the IAC.

Aims: To investigate the distances between inferior alveolar canal (IAC) to both mesial and distal roots of mandibular second molar (M2) and inferior mandibular cortex. Materials and Methods: This retrospective study was carried out on 110 patients (50 women and 60 men) aged between 20 and 50 years. Each patient took one panoramic image and one digital intraoral image for the right side at second molar area. Patients were evaluated by gender and age (coterie I = 54 and coterie II = 56). Data were analyzed by using the Statistical Package for the Social Sciences Statistics software, version 22.0 (IBM, Chicago, Illinois), and the mean values were compared using the compare means test. Results: The results showed no significant differences at P > 0.05 between men and women in the distances of M2 roots and mandibular cortex to IAC by both digital techniques. However, the roots of M2 of women (2.7 and 1.8 mm by digital panoramic, 2.6 and 2 mm by digital intraoral image) and of those aged less than 35 years (3.1 and 2.45 mm by digital panoramic, 3.1 and 2.56 mm by digital intraoral image) were near to the IAC. Conclusion: Preoperative investigations to know the degree of vicinity of roots of M2 and lower jaw canal by using of digital radiographic imaging (intraoral and panoramic) depending on their properties (image enhancement, measuring tools, and updating data) have high values to avoid a complications such as distress and numbness after dental procedures by direct damage or pushed toxic dental materials in this tunnel.