Inferior Alveolar Nerve Impairment Research Articles

A CASE OF OSTEOPETROSIS: UNUSUAL MAXILLOFACIAL PRESENTATION AND SUCCESSFUL DENTAL IMPLANT RESTORATIONS

<h3>Clinical Presentation</h3> A patient presented with malaligned and rotated, missing, unerupted, and partially erupted/maldeveloped teeth seeking care to improve her masticatory function. She had impaired hearing and vision, but no neurologic symptoms. A panoramic radiograph, a lateral cephalometric radiograph, and a medical CT scan were reviewed. The radiographic examination revealed a skeletal Class III relationship. Sclerosis related to osteopetrosis was seen throughout the maxilla, cranial base, and cervical spine. A train track–like radiopaque formation was noted bilaterally within the mandibular inferior alveolar canals. No symptoms related to inferior alveolar nerve impairment were noted. <h3>Differential Diagnosis</h3> Multiple impacted and malformed teeth were unusual presentations, leading to the diagnosis of osteopetrosis. Other syndromes, such as cleidocranial dysostosis and Gardner syndrome, can also have similar features. <h3>Diagnosis and Management</h3> The treatment comprised a maxillary overdenture and an implant-supported mandibular prosthesis. Despite the increased risk of failed osseointegration, the implants placed in the mandible have been successful for greater than 8 years. <h3>Discussion</h3> Osteopetrosis is a disorder characterized by impaired osteoclast function, leading to hyperdense, hypovascular, brittle bone. When considering dental implant placement in a patient with osteopetrosis, one must be wary of the increased possibility of bone fracture or osteomyelitis and the decreased likelihood of successful osseointegration because of hypovascularity. This case report describes successful osseointegration of multiple dental implants supporting a fixed mandibular prosthesis with long-term survival. Therefore, implant placement should not be excluded on the basis of an osteopetrosis diagnosis alone. Rather, one should evaluate the sclerosis radiographically in relation to intended implant sites.

High resolution MRI for quantitative assessment of inferior alveolar nerve impairment in course of mandible fractures: an imaging feasibility study

The purpose of this study was to evaluate a magnetic resonance imaging (MRI) protocol for direct visualization of the inferior alveolar nerve in the setting of mandibular fractures. Fifteen patients suffering from unilateral mandible fractures involving the inferior alveolar nerve (15 affected IAN and 15 unaffected IAN from contralateral side) were examined on a 3 T scanner (Elition, Philips Healthcare, Best, the Netherlands) and compared with 15 healthy volunteers (30 IAN in total). The sequence protocol consisted of a 3D STIR, 3D DESS and 3D T1 FFE sequence. Apparent nerve-muscle contrast-to-noise ratio (aNMCNR), apparent signal-to-noise ratio (aSNR), nerve diameter and fracture dislocation were evaluated by two radiologists and correlated with nerve impairment. Furthermore, dislocation as depicted by MRI was compared to computed tomography (CT) images. Patients with clinically evident nerve impairment showed a significant increase of aNMCNR, aSNR and nerve diameter compared to healthy controls and to the contralateral side (p < 0.05). Furthermore, the T1 FFE sequence allowed dislocation depiction comparable to CT. This prospective study provides a rapid imaging protocol using the 3D STIR and 3D T1 FFE sequence that can directly assess both mandible fractures and IAN damage. In patients with hypoesthesia following mandibular fractures, increased aNMCNR, aSNR and nerve diameter on MRI imaging may help identify patients with a risk of prolonged or permanent hypoesthesia at an early time.

Outcomes after mandibular third molar coronectomy

ABSTRACT Coronectomy is an alternative technique to mandibular third molar removal to avoid inferior alveolar nerve impairment. It is indicated in cases where the dental roots are in close relationship with the nerve which results in a higher risk of damage and paresthesia. The coronectomy technique is considered a safe method to prevent inferior alveolar nerve injury, however it shows particular postoperative outcomes as migration and exposure of the retained roots, and possibility of additional intervention. The aim of this case series is to describe four different outcomes from coronectomy, in patients treated by the same protocol. The outcomes ranged from asymptomatic to migration, infection and root removal. Although the variety of outcomes, none of the patients showed inferior alveolar nerve impairment. Therefore, the main objective of coronectomy was reached.

Coronectomy of mandibular third molars: a clinical and radiological study of 231 cases with a mean follow-up period of 5.7 years

Coronectomy is a widely accepted treatment for mandibular third molars that are in close relationship to the mandibular canal. However, long-term studies on morbidity following this procedure have not been presented. The aim of this study was to examine the long-term morbidity after coronectomy, with sensory disturbances of the inferior alveolar nerve (IAN) and root migration as the primary outcome variables. A total of 231 mandibular third molar coronectomies were performed in 191 patients with a mean follow-up period of 5.7years (range 1–12years). The prevalence of IAN injury was 1.3%, and 3.5% of the retained roots were removed. None of the reoperations to remove the retained roots caused IAN impairment. Infections occurred in 11.7% of the cases and all were treated with antibiotics. Overall, 97% of the retained roots showed signs of migration and 65% showed signs of rotation. Therefore, coronectomy of the mandibular third molars with an intimate relationship to the mandibular canal seems to be a safe treatment modality with a good long-term prognosis.

The correlation between Rood and Shehab’s radiographic features and the incidence of inferior alveolar nerve paraesthesia following odontectomy of lower third molars

Background: Odontectomy of lower third molar has a potential risk for inferior alveolar nerve impairment. Paresthesia of inferior alveolar nerve has often been associated with close relationship between the apex of lower third molar and mandibular canal. Rood and Shehab’s category has been commonly used for radiological prediction of inferior alveolar nerve injury following third molar surgery. Purpose: This study aimed to determine whether there was correlation between Rood and Shehab’s radiographic features and the incidence of inferior alveolar nerve paraesthesia following odontectomy of lower third molar. Method: This was a retrospective cross-sectional study, using data obtained from the dental record of patients who had undergone odontectomy of lower third molars in Dental hospital of Universitas Airlangga during 2 years period. Samples were cases that, from presurgical radiograph, showed close relationship between lower third molar roots and mandibular canal. The case and non-case groups were assigned based on the presence of paraesthesia and non-paraesthesia of inferior alveolar nerves, respectively. Based on Rood and Shehab’s category, the samples collected were then classified into two groups which were those whose relationship matched and did not match with the category, respectively. Data were analyzed using Chi-square correlation test. Result: Of 975 odontectomy cases included in this study, 80 cases were taken as study samples consisting of 15 and 65 cases assigned, respectively, as case and non-case. The 32 cases matched with the criteria of Rood and Shehab's category while the remainder of 48 cases did not. Of 32 cases which met the criteria of Rood and Shehab’s relationship, only 5 cases showed paraesthesia, whereas out of 48 cases which did not met the criteria 10 cases showed paraesthesia. Statistical analysis showed significance value of 0.770 (p&gt;0.05) indicating that there was no significant correlation between relations of third molar root and mandibular canal, based on Rood and Shehab’s category, and the incidence of inferior alveolar nerve paraesthesia. Conclusion: There was no correlation between Rood and Shehab’s radiographic features and the incidence of paraesthesia of inferior alveolar nerve following odontectomy of lower third molars.

Magnetic resonance imaging of the inferior alveolar nerve with special regard to metal artifact reduction

PurposeMagnetic resonance imaging (MRI) is an excellent imaging modality for displaying peripheral nerves. Since the knowledge about MRI of the inferior alveolar nerve (IAN) is limited, this pilot study aims to identify the prospects and limitations of MRI of the IAN, with special consideration of metal artifacts. Materials and methodsInitially, in vitro MRI of a dental implant was performed to establish an optimized protocol for metal artifact reduction using WARP sequences (a software package provided by Siemens Healthcare, Erlangen, Germany) including view angle tilting (VAT) and slice-encoding metal artifact correction (SEMAC) techniques. MRI with this optimized protocol was performed in three volunteers and four patients presenting with postoperative IAN impairment. Measuring the evaluable area and the artifact size was performed to assess the benefit of the specific artifact reduction sequences. ResultsIn vitro imaging of a dental implant demonstrated that WARP sequences with VAT and SEMAC techniques led to a volume reduction of the artifact of up to 69.1%. Observations in both volunteers and patients with neurosensory IAN impairment showed a distinct artifact reduction with the MRI protocol adapted to metallic materials. Additionally VAT and SEMAC techniques improved the imaging due to further artifact reduction. As a main drawback of the VAT technique, the image quality was compromised by a blurring effect. Still, on 3-T MRI the resolution was high enough to reveal even fine structures. Imaging of the IAN was successful in all cases despite metallic material in the region of interest, and structural IAN changes could be detected in correlation with clinical symptoms. ConclusionIn contrast to conventional radiography and computed tomography, MRI can directly depict the IAN and provide reliable information on its position and exact course within the mandible. MRI offers an objective assessment of IAN injuries, supporting the decision-making process regarding surgical exploration and microneural repair. With the advent of specialized MRI techniques such as VAT and SEMAC, reduction of metal artifacts is considerably improved.

Piezosurgery for the Lingual Split Technique in Lingual Positioned Impacted Mandibular Third Molar Removal: A Retrospective Study.

The aim of this study was to evaluate the effect and safety of lingual split technique using piezosurgery for the extraction of lingual positioned impacted mandibular 3rd molars with the goal of proposing a more minimally invasive choice for this common surgery.Eighty-nine consecutive patients with 110 lingual positioned impacted mandibular 3rd molars requiring extraction were performed the lingual split technique using piezosurgery. One sagittal osteotomy line and 2 transverse osteotomy line were designed for lingual and occlusal bone removal. The success rate, operative time, postoperative outcome, and major complications (including nerve injury, mandible fracture, severe hematoma or edema, and severe pyogenic infection) were documented and analyzed.All impacted mandibular 3rd molars were successfully removed (110/110). The average time of operation was 14.6 minutes (ranged from 7 to 28 minutes). One hundred and seven extraction sites (97.3%) were primary healing. Pain, mouth opening, swelling, and PoSSe scores on postoperative 7-day were 0.34 ± 0.63, 3.88 ± 0.66(cm), 2.4 ± 0.2(cm), and 23.7 ± 5.9, respectively. There were 6 cases (5.5%) had lingual nerve disturbance and 3 cases (2.7%) developed inferior alveolar nerve impairment, and achieved full recovery within 2 months by neurotrophic drug treatment.Our study suggested piezosurgery for lingual split technique provided an effective way for the extraction of lingual positioned and deeply impacted mandibular 3rd molar.

Inferior alveolar nerve injuries associated with mandibular fractures at risk: a two-center retrospective study.

The aim of the study was to investigate the incidence of the inferior alveolar nerve (IAN) injury in mandibular fractures. This study is based on two databases that have continuously recorded patients hospitalized with maxillofacial fractures in two departments-Department of Maxillofacial Surgery, Vrije Universiteit University Medical Center, Amsterdam, the Netherlands, and Division of Maxillofacial Surgery, San Giovanni Battista Hospital, Turin, Italy. Demographic, anatomic, and etiology variables were considered for each patient and statistically assessed in relation to the neurosensory IAN impairment. Statistically significant associations were found between IAN injury and fracture displacement (p = 0.03), isolated mandibular fractures (p = 0.01), and angle fractures (p = 0.004). A statistically significant association was also found between IAN injury and assaults (p = 0.03). Displaced isolated mandibular angle fractures could be considered at risk for increased incidence of IAN injury. Assaults seem to be the most important etiological factor that is responsible for IAN lesions.

Labial sensory impairment following extraction of impacted mandibular third molars

Introduction: The purpose of this study was a prospective investigation into the occurrence of impairment of labial sensation after surgical removal of impacted third molars. Aims and Objectives: The aim of this study was to determine the incidence of postoperative sensory impairment of inferior alveolar nerve (IAN) after extraction of impacted mandibular third molars. Materials and Methods: The study sample consisted of 200 patients who were indicated for removal of impacted mandibular third molars. Extraction of the impacted tooth was done by using surgical bur technique. Postoperatively, patients were evaluated for impairment of labial sensation. Objective evaluation of IAN was carried out using light touch sensation, tactile discrimination, pain awareness, and two point discrimination. Results: Of 200 subjects, only two patients showed neurosensory deficit in relation to IAN. Conclusion: The main cause of neurosensory impairment was due to variables associated with tooth position, degree of impaction, operator skill and also depth of impaction and age of the patient.

Does Computed Tomography Prevent Inferior Alveolar Nerve Injuries Caused by Lower Third Molar Removal?

To verify the utility of computed tomography (CT) in preventing inferior alveolar nerve (IAN) injury owing to lower third molar extraction in close relation to the IAN on orthopantomogram. A retrospective cohort study design of 150 lower third molar extractions was performed. Patients were divided in 2 groups: the CT group (n = 95) underwent panoramic radiography and mandibular CT and the control group (n = 55) underwent only panoramic radiography. Six extractions (4%) in the control group and 15 (10%) in the CT group resulted in IAN impairment (P > .05). Logistic regression models did not show that undergoing CT decreased the risk of IAN injury from lower third molar extraction. Patient age and positive radiographic signs (darkening of the root and narrowing of the inferior alveolar canal) were associated with more requests for CT scanning. CT does not seem to significantly decrease the risk of producing IAN injury.

3-Dimensional Imaging for Lower Third Molars: Is There an Implication for Surgical Removal?

Surgical removal of impacted third molars may be the most frequent procedure in oral surgery. Damage to the inferior alveolar nerve (IAN) is a typical complication of the procedure, with incidence rates reported at 1% to 22%. The aim of this study was to identify factors that lead to a higher risk of IAN impairment after surgery. In total 515 surgical third molar removals with 3-dimensional (3D) imaging before surgical removal were retrospectively evaluated for IAN impairment, in addition to 3D imaging signs that were supposed predictors for postoperative IAN disturbance. Influence of each predictor was evaluated in univariate and multivariate analyses and reported as odds ratio (OR) and 95% confidence interval (CI). The overall IAN impairment rate in this study was 9.4%. Univariate analysis showed narrowing of the IAN canal (OR, 4.95; P < .0001), direct contact between the IAN and the root (OR, 5.05; P = .0008), fully formed roots (OR, 4.36; P = .045), an IAN lingual course with (OR, 6.64; P = .0013) and without (OR, 2.72; P = .007) perforation of the cortical plate, and an intraroot (OR, 9.96; P = .003) position of the IAN as predictors of postoperative IAN impairment. Multivariate analysis showed narrowing of the IAN canal (adjusted OR, 3.69; 95% CI, 1.88 to 7.22; P = .0001) and direct contact (adjusted OR, 3.10; 95% CI, 1.15 to 8.33; P = .025) to be the strongest independent predictors. Three-dimensional imaging is useful for predicting the risk of postoperative IAN impairment before surgical removal of impacted lower third molars. The low IAN impairment rate seen in this study-compared with similar selected study groups in the literature of the era before 3D imaging-indicates that the availability of 3D information is actually decreasing the risk for IAN impairment after lower third molar removal.

Evaluation of the change of lower lip sensation after inferior alveolar nerve block by using the electric pulp tester

J Korean Assoc Oral Maxillofac Surg 2011;37:464-9) Evaluation of the change of lower lip sensation after inferior alveolar nerve block by using the electric pulp tester Myong-Suk Ku, Jin Wook Kim, Young Hoon Jeon, Tae Geon Kwon, Sang Han Lee Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Daegu, Korea Introduction: As dental implant surgery is becoming increasingly popular, it has become one of the causes for the hypesthesia of the inferior alveolar nerve, along with other surgical procedures, such as a third molar extraction. In addition, it tends to cause legal problems between the operator and patient. Therefore, there must be a proper method that is reliable, objective and economical to assess the nerve impairment. For this reason, an attempt was made to use an Electric Pulp Tester to assess inferior alveolar nerve block anesthesia. Materials and Methods: Thirty patients were tested. Electric pulp testing of the lower jaw skin was performed at the three different times, before anesthesia, at the onset of sensory changes and after 15 minutes waiting from the onset, and on the 10 points of the chin, which produced 10 sections on the skin area. Results: Twenty seven patients (90%) could feel the electric stimulus on the chin at all 10 points before local anesthesia and the scores represent the statistical differences between the right and left points except R4 and L4. After anesthesia, the difference between the right and left points (L3-R3, L4-R4, L5-R5) increased significantly with time but two points (L2, R2) showed no significant difference. The scores on the left chin (L3, L4, L5) increased, whereas the other points (R1-R5, L1, L2) showed no significant differences. Conclusion: This study highlights the potential clinical use of an electric pulp tester for an assessment of inferior alveolar nerve impairment.

Evaluation of sensory impairment of inferior alveolar nerve following mandibular bilateral sagittal split osteotomy-by clinical and electrophysiological tests

Evaluation of sensory impairment of inferior alveolar nerve following mandibular bilateral sagittal split osteotomy-by clinical and electrophysiological tests

Incidence and evolution of inferior alveolar nerve lesions following lower third molar extraction

To calculate the incidence of inferior alveolar nerve (IAN) damage due to lower third molar extraction and to describe the evolution of IAN sensitivity and the prognosis of IAN damage based on preoperative data. A retrospective study of 4995 lower third molar extractions in 3513 outpatients. Fifty-five extractions (1.1%) resulted in IAN impairment. Cox regression analysis showed age to be a risk factor for the persistence of IAN injury due to lower third molar extraction. The sensation recovery rate was higher in the first 3 months. Fifty percent of the patients showed full recovery after 6 months. Most cases of IAN impairment following lower third molar extraction recover within 6 months, though in some cases recovery takes more than 1 year. Older patients are at an increased risk of incomplete recovery of chin and lip sensibility after third molar extraction.