Disturbance Of Inferior Alveolar Nerve Research Articles

Coronectomy of mandibular third molars: a systematic literature review and case studies.

Extraction of mandibular third molars (M3M) close to the inferior alveolar nerve (IAN) has a higher risk of neurological disturbance. This review aims to evaluate the evidence supporting the use of the coronectomy technique compared to complete extraction for such M3Ms. Case studies by a specialist oral and maxillofacial surgeon are included to illustrate clinical practice. Three databases (Cochrane Library, Embase, PubMed) were searched (November 2020). Additional articles were sought by hand searching the reference list of included articles. All studies published in English comparing outcomes of coronectomy with complete extraction with at least 50 subjects and 6months follow-up were included. Of the six included studies, five reported a lower rate of IAN disturbance after coronectomy compared with complete extraction. There were no reported cases of lingual nerve disturbance. Other outcomes of coronectomy such as pain, infection, alveolar osteitis were either similar or lower compared to complete extraction. There were high rates of root migration but low rates of exposure and reoperation. Follow-up protocols varied considerably. There is medium quality evidence to support the option of coronectomy for high risk M3M cases. Further studies to develop follow-up protocols to assist general dental practice is warranted.

Recovery of inferior alveolar nerve by photobiomodulation therapy using two laser wavelengths: A behavioral and immunological study in rat

Postoperative sensory disturbances of inferior alveolar nerve (IAN) are major challenges in dental procedures. We aimed to investigate the effect of photobiomodulation therapy (PBMT) with 810 nm and 980 nm diode lasers on behavioral and immunological factors in a rat IAN crush model. Seventy-two rats were randomly assigned to the four groups of 810 nm laser (crush injury+810 nm laser; 6 J/cm2, 15 sessions, every 48 h), 980 nm laser (crush injury+980 nm laser; same protocol), control (crush injury without irradiation), and sham surgery (no crush injury and no irradiation). The neurosensory response of IAN was evaluated by Von Frey behavioral test before (baseline) and post-surgery in a period of one month. Changes of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), nuclear factor-kappa B (NF-κB), TNF-α, and IL-1β, were assessed on days 2 and 30 post injury. Data were analyzed for significant differences by repeated measures and one-way ANOVA (p < .05).One day after surgery, all rats subjected to nerve injury showed significant increase in the withdrawal threshold of von Frey test compared to the baseline (p = .02 for control and p = .03 for laser groups). The threshold gradually returned to the baseline scores in 810 nm, 980 nm, and control groups from days 11, 17, and 29, respectively. There was a significant lower withdrawal threshold in 810 nm and 980 nm laser groups compared to the control group in days 11 to 19 and 9 to 23, respectively. At both time points, the levels of NGF and BDNF were significantly higher in 810 nm laser group compared to the control group. There was a significant difference between laser and control groups regarding NF-κB expression (all p values<.001). TNF-α and IL-1β were significantly lower in laser groups compared to the control group (all p values < .001). PBMT with 810 and 980 nm diode laser protocol used in this study, promoted the neurosensory recovery of IAN after crush injury in rats. In addition, application of 810 nm diode laser was associated with more improvement in immunological responses compared to that of 980 nm laser.

Usefulness of piezoelectric surgery to reduce neurosensory disturbances of inferior alveolar nerve after SSRO

Usefulness of piezoelectric surgery to reduce neurosensory disturbances of inferior alveolar nerve after SSRO

Subjective Alveolar Nerve Function After Bilateral Sagittal Split Osteotomy or Distraction Osteogenesis of Mandible

The present retrospective cohort study compared the subjective inferior alveolar nerve (IAN) function after distraction osteogenesis (DOG) and bilateral sagittal split osteotomy (BSSO) in mandibular advancement surgery. Treatment consisted of correction of a retrognathic mandible using DOG (30 patients) or BSSO (35 patients). Subjective IAN function was recorded using a questionnaire 1 year after surgery. A total of 130 IANs were evaluated. In 37 nerves (28.5%), an IAN disturbance was observed. In this group of 37 nerves, BSSO had been performed in 26 (70.3%) and DOG in 11 (29.7%). After eliminating confounders (eg, age, amount of advancement, gender), no significant difference (odds ratio 0.652, 95% confidence interval 0.221 to 1.920) was found. Age was significantly related to subjective IAN disturbances for women but not for men. This was seen in women older than 22 years and increased for women older than 36 years to an odds ratio of 22.8 (95% confidence interval 2.580 to 201.488). Satisfaction also correlated with age, independent of gender. No difference was found in subjective IAN disturbances after 1 year between DOG and BSSO for lengthening the mandible.

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.

Predictors of Mandibular Involvement in Cancers of the Oromandibular Region

Invasion of the mandible by oral squamous carcinoma is not only a relative contraindication to mandible conservation but also an indicator of poor prognosis. This study looks at clinical, radiologic, and operative variables that may help in predicting mandibular bone involvement. A prospective study was carried out to evaluate the mandibular involvement and its predictors in 51 cases of oral squamous carcinoma located in the mandibular region. All patients underwent segmental- or hemimandibulectomy. A detailed clinical examination was followed by radiologic assessment and operative assessment. Statistic analysis was carried out by chi(2) test (odds ratio [OR] with a significance level of 5%). Multivariate analysis was carried out by logistic regression analysis. Univariate analysis identified location of tumor on lower alveolus (OR = 8.5), sensory disturbances of inferior alveolar nerve (OR = 16.2), location of tumor within 1 cm of mandible (OR = 1.4), presence of findings on periosteal striping (OR = 2.0) like subperiosteal reaction (OR = 3.5), cortical expansion (OR = 8.8) and presence of pathologic fracture (OR = 2.3) as predictor of bone invasion. Grade of tumor (P = .05) and radiologic bone involvement (P = .02) were found to be significant independent predictors of pathologic bone involvement on multivariate analysis. It is possible to identify mandibular invasion in almost all cases of oral squamous carcinoma by combining clinical examination, radiologic findings, and findings on periosteal stripping. This helps surgeons to make an informed preoperative and intraoperative decision about mandibular conservation. However, one should be careful when evaluating bone involvement on periosteal stripping as this cannot be recommended as a method of choice due to fear of tumor dissemination and violation of oncologic principles.

Poster 254: Improvement of TMD Following Intraoral Vertical Ramus Osteotomy (IVRO)

Like sagittal split ramus osteotomy (SSRO), intraoral vertical ramus osteotomy (IVRO) is a useful surgical procedure aiming good occlusion and esthetic for patients with mandibular prognathism. Moreover, it is said that temporomandibular joint disorders (TMD) improved by IVRO. The purpose of this study was to assess the improvement of TMD in patients with the jaw deformities who had already undergone IVRO at our Department of Oral-maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital. We performed 49 osteotomies of IVRO to correct mandibular prognathism on 29 patients during the period from August 2001 to December 2006. Bilateral IVRO was performed on 20 patients who had mild mandibular prognathism. Unilateral IVRO was performed with accompanying SSRO on the shifted side on nine patients who had mandibular prognathism with skeletal facial asymmetry. Bilateral IVRO was performed on the two patients with type IIIa TMD. The condyles were significantly displaced anteroinferiorly following the surgery. During the postoperative follow-ups, there was significant movement of the condyles to a slightly anteroinferior position. As a result, TMD improved in both cases. It has been reported that the operation time, bleeding volume, and neurosensory disturbances of inferior alveolar nerve were all less of IVRO than that of SSRO. In addition, our study revealed that IVRO could not only correct the jaw deformity but also improve the type IIIa TMD. We suggest that IVRO provides an excellent outcome for patients undergoing orthognathic surgery.

An evaluation of clinical and electrophysiologic tests in nerve injury diagnosis after mandibular sagittal split osteotomy

The yield of clinical sensory tests and electrophysiologic tests in the diagnostics of inferior alveolar nerve (IAN) damage after bilateral sagittal split osteotomy (BSSO) was studied. The diagnostic value of these tests was evaluated by comparing the test results to the degree of nerve damage at the end of the operation as documented by means of the intraoperative nerve conduction recording of the IAN. Twenty patients undergoing BSSO were analysed preoperatively and 2 weeks postoperatively. The frequency of the IAN disturbance ranged from 10% to 94% depending on the test method and the test site used. Of the clinical sensory tests, the touch detection threshold (TD) test was the most sensitive and clinically useful test. It also correlated best with the electrophysiologically verified intraoperative nerve damage (R=−0.603,P =0.017 on the right, R=−0.626, P=0.01 on the left). The blink reflex and quantitative cold detection threshold tests were almost as often abnormal as the TD-test, but nerve conduction study (NCS) was the most sensitive (88%) of all clinical and electrophysiologic tests. The frequency of abnormal findings in the electrophysiologic tests indicating IAN injury, 75% on the right side and 90% on the left side, corresponded exactly with the figures of subjective sensory alteration. Almost all electrophysiologic tests showed obvious associations with the objectively verified IAN damage. All tests, except the NCS, showed only moderate sensitivity. Specificity of the tests was generally high, the only exceptions being the TD test and the NCS. To increase the diagnostic accuracy of the testing and to detect different types of damage in different nerve fibre populations, a combination of different sensory and electrophysiologic tests is recommended.