Anatomical Analysis of Inferior Alveolar Nerve Relation to Mandibular Posterior Teeth Using Cone Beam Computed Tomography: A Retrospective Radiographic Analysis Study.

Introduction: Cone beam computed tomography (CBCT) is reliable in the assessment of structures related to teeth. The assessment of the inferior alveolar neurovascular (IAN) bundle location using CBCT is considered one of its prime uses in different mandibular surgeries. Methodology: Retrospective CBCT data of patients presented to the institute were assessed to measure relations of IAN. Measurements were taken to assess the bone thickness adjacent to IAN, the superior-inferior dimension between the canal and the teeth, and the dimension between the canal and the inferior border of the mandible. Results: Out of the 170 patients the root apices nearest to the IAN were that of the second molars (1.76 ± 1.86 mm). The IAN was closest to the inferior border of the mandible at the roots of the second molars (8 ± 3.4 mm). The buccal bone thickness had its greater dimension buccal to the IAN at the area of the second molar (5.16 ± 1.26 mm). Conclusion: Two mini-plates in trauma do not increase the risk of injury. It is advisable in apicectomy not to extend 1.5 mm apically. The thickness of the nerve-lateralization window should not exceed 2 mm. In body osteotomy procedure, perform surgery anterior to premolars as much as possible.

Evaluating the presence of IAN injury in patients with juxta-apical radiolucency after third molar surgery: a retrospective cohort study.

BACKGROUND: Juxta-apical radiolucency (JAR) has been presented as a radiographic sign, suggestive of the IAN injury through third molar surgery. This study aimed to evaluate the relation of JAR with IAN injury in cone-beam computed tomography (CBCT) images and to determine whether the presence of JAR is related to tooth angulation, proximity to the mandibular canal, position to the IAN, and thinning of the cortical plates. METHODS: Of an initial sample of 545 mandibular third molars, a total of 75 JAR+ and 75 JAR- teeth were evaluated by CBCT. We assessed the relationship between the presence of JAR in cone-beam computed tomography (CBCT) images and the presence of IAN injury after mandibular third molar surgeries. Moreover, we investigated whether the presence of IAN injury is related to tooth angulation, proximity to the mandibular canal, position to the IAN, and thinning of the cortical plates. Descriptive statistics, Chi-square test, and Fisher's exact test were performed for statistical analysis. RESULTS: A significant relationship was found between JAR and temporary IAN injury (P = 0.036). However, there was no case of permanent IAN injury. IAN injury showed no significant relationship with the tooth angulation, position to IAN and proximity to the mandibular canal, lingual cortical plate thinning, sex, and age. CONCLUSIONS: JAR is generally in contact with the mandibular canal, and some degree of cortical thinning can be found in most cases. In this study, JAR was significantly related to temporary IAN injury. JAR may increase the risk of nerve injury during the surgical removal of third molars.

Coronectomy: a retrospective outcome study.

PURPOSE: Inferior alveolar nerve (IAN) injury is reported as a complication following surgical removal of lower third molars. In cases where the IAN is intimately related to the roots of the tooth, coronectomy may be performed as an alternative. The objectives of this study were to record operative indications for coronectomy and assess the short- and long-term post-operative outcomes following coronectomy. METHODS: This retrospective study included patients (19-95 years old) that had coronectomies carried out in the Edinburgh Dental Institute and Chalmers Dental Centre within the last 10 years. The patients were invited by letter to attend a review appointment. High-risk radiographic signs and short- (≤ 3 months) and long-term complications (> 3 months) were recorded. RESULTS: A total of 124 patients were invited to participate and a total 28 patients returned for review. From the rest of the patients, data was extracted from their dental records. IAN injury was reported in 5 cases (4.3%) as a short-term complication and in 2 cases (3.5%) as a long-term complication. One patient presented with eruption of roots at the review appointment 7 years following surgery. In this study, 'very' long-term complications were recorded as the 28 patients that returned for a review, were seen on an average of 4.8 years post-operation. CONCLUSIONS: Coronectomy is a relatively safe technique for preservation of the IAN. However, prospective large scale research is needed to more accurately report on the prevalence of short- and long-term complications.

Computer-Aided Design/Computer-Aided Manufacturing Cutting Guides for Odontectomy of Deeply Impacted Mandibular Third Molars.

AIM: To evaluate a new technique for surgical removal of deeply impacted mandibular third molars (DIMTM), using computer-guided cutting guide to maintain inferior alveolar nerve (IAN) integrity and the covering buccal bone. PATIENTS AND METHODS: Eighteen cases indicated for removal of DIMTM. Cone-beam Computed Tomography (CBCTs) used to determine the tooth's relation to the IAN. Computer-guided software used for fabrication of surgical cutting guide stent to expose the impacted tooth and repositioning of bone after odontectomy without fixation. Clinical assessment included a neurosensory deficit of IAN, pain using a visual analogue scale (VAS), facial swelling, and maximal mouth opening (MMO). CBCTs were taken immediately and six months postoperatively to evaluate position and healing of bone. RESULTS: None of the patients showed a permanent neurological deficit of IAN while all patients showed normal parameters of pain, facial swelling and MMO. CONCLUSION: this technique has shown the accurate determination of the bony window cuts with subsequent preservation of IAN and external oblique ridge.

Influence of tooth sectioning technique and various risk factors in reducing the IAN injury following surgical removal of an impacted mandibular third molar.

A prospective study on 100 patients presented with a mesioangular impacted mandibular third molar in close proximity to the inferior alveolar nerve canal (IANC) was done to evaluate the efficacy of tooth sectioning in reducing the incidence of inferior alveolar nerve (IAN) injury during their surgical removal. The patients were divided into two groups: group A, where tooth sectioning was not performed, and group B, where tooth sectioning was performed. Patients were recalled 7 days, 15 days, 30 days, 3 months, and 6 months postoperatively for evaluation of nerve injury and its recovery. A total of 13 patients suffered from nerve damage out of which 10 patients (10/50 or 20 %) belonged to group A and 3 patients (3/50 or 6 %) belonged to group B. All patients showed complete recovery from nerve damage within 6 months except 1 patient. The result of the study showed that tooth sectioning significantly reduces the incidence of nerve damage by 14 %. Deviation of the IANC, increased depth of the impacted tooth, intraoperative hemorrhage within socket/nerve exposure, and increased duration of procedure were found to be the significant risk factors associated with nerve injury.

Clinical outcome of conservative treatment of injured inferior alveolar nerve during dental implant placement.

OBJECTIVES: Infererior alveolar nerve (IAN) damage may be one of the distressing complications occurring during implant placement. Because of nature of closed injury, a large proportion is approached non-invasively. The purpose of this study was to analyze the outcomes of conservative management of the injured nerve during dental implant procedure. MATERIALS AND METHODS: Sixty-four patients of implant related IAN injury, who were managed by medication or observation from January 1997 to March 2007 at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, were retrospectively investigated. The objective tests and subjective evaluations were performed to evaluate the degree of damage and duration of sensory disturbance recovery. Tests were performed on the day of the first visit and every two months afterward. Patient's initial symptoms, proximity of the implant to the IAN, time interval between implant surgery and the first visit to our clinic, and treatment after implant surgery were analyzed to determine whether these factors affected the final outcomes. RESULTS: Among the 64 patients, 23 had a chief complaint of sensory disturbance and others with dysesthesia. The mean time until first visit to our hospital after the injury was 10.9 months.One year after nerve injury, the sensation was improved in 9 patients, whereas not improved in 38 patients, even 4 patients experienced deterioration. Better prognosis was observed in the group of patients with early visits and with implants placed or managed not too close to the IAN. CONCLUSION: Nearly 70% of patients with IAN injury during implant placement showed no improvement in sensation or dysesthesia with the conservative management. Earlier decision for active treatment needs to be considered because of possibility of deterioration of symptoms and unsatisfactory recovery.

Clinical outcome of conservative treatment of injured inferior alveolar nerve during dental implant placement

OBJECTIVES: Infererior alveolar nerve (IAN) damage may be one of the distressing complications occurring during implant placement. Because of nature of closed injury, a large proportion is approached non-invasively. The purpose of this study was to analyze the outcomes of conservative management of the injured nerve during dental implant procedure. MATERIALS AND METHODS: Sixty-four patients of implant related IAN injury, who were managed by medication or observation from January 1997 to March 2007 at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, were retrospectively investigated. The objective tests and subjective evaluations were performed to evaluate the degree of damage and duration of sensory disturbance recovery. Tests were performed on the day of the first visit and every two months afterward. Patient's initial symptoms, proximity of the implant to the IAN, time interval between implant surgery and the first visit to our clinic, and treatment after implant surgery were analyzed to determine whether these factors affected the final outcomes. RESULTS: Among the 64 patients, 23 had a chief complaint of sensory disturbance and others with dysesthesia. The mean time until first visit to our hospital after the injury was 10.9 months.One year after nerve injury, the sensation was improved in 9 patients, whereas not improved in 38 patients, even 4 patients experienced deterioration. Better prognosis was observed in the group of patients with early visits and with implants placed or managed not too close to the IAN. CONCLUSION: Nearly 70% of patients with IAN injury during implant placement showed no improvement in sensation or dysesthesia with the conservative management. Earlier decision for active treatment needs to be considered because of possibility of deterioration of symptoms and unsatisfactory recovery.