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Objectives To identify the incidence of inferior alveolar nerve injury following extraction of mandibular third molars with confirmed “high-risk” features on Cone-Beam Computed Topography scans and establish any risk factors which significantly increase the chances of sustaining an inferior alveolar nerve injury. Study Design A retrospective analysis of outcomes following surgical extraction of 500 mandibular third molars over a 5-year period. All teeth showed signs of contact with, or compression of the inferior alveolar nerve on Cone-Beam Computed topography scans. Results The overall incidence of inferior alveolar nerve injury was 6.6%, with permanent neuropathies accounting for 1.8% within this “high risk” cohort. Statistically significant factors shown to increase the risk of nerve injury, included increasing age (p=0.002), compression of the nerve evident on Cone Beam Computed topography scan (p=0.005) and buccal or interradicular position of the nerve (p=0.042). Discussion Results indicate a low incidence of inferior alveolar nerve injury, particularly given the “high-risk” nature of all teeth which were extracted. It highlights the benefits of Cone-Beam Computed Topography scans in planning of surgery. This data is an important contribution to the existing literature and valuable in the consent procedure for patients undergoing surgical removal of mandibular third molars in contact with the inferior alveolar nerve.

Preoperative assessment is essential to prevent inferior alveolar nerve (IAN) injury during surgical extraction of the lower third molar (LM3). Here, we aimed to establish an assessment system to predict IAN injury during surgical extraction of the LM3. We conducted a retrospective cohort study on 115 patients diagnosed as 'high-risk' based on our previous risk assessment method involving three anatomical features of the inferior alveolar canal using computed tomographic (CT) images. We evaluated the occurrence of neurosensory impairment in these high-risk patients, and its association with novel anatomic features based on CT images. Neurosensory impairments were observed in 19 patients (16.5%). The inferior alveolar canal major diameter (p0.0001) and lingual bone thickness (p = 0.0039) were significantly associated with the occurrence of neurosensory impairment during LM3 extraction. Receiver operating characteristic curves were used to determine cut-off values of these quantitative factors to specifically predict IAN injury. Preoperative risk assessment with quantitative factors based on anatomical features observed on CT images may facilitate more appropriate surgical planning for patients at a high risk of IAN injury.

An over-representation of women in dental implant-related inferior alveolar nerve injuries (IANIs) is recognized in the literature but has not been investigated. Therefore, a nationwide retrospective register study was conducted to analyse how IANIs compare with other implant-related complications (infection, implant malposition, lack of bone at implant site, mechanical damage, or failed osseointegration) separately in women and men. Financially compensated malpractice claims related to dental implant surgery were collected from the Finnish Patient Insurance Centre for the years 1997-2013, while the total number of nationally placed implants was ascertained from the implant register held by the Finnish Institute for Health and Welfare. In the 242 complications, the following were analysed: age of subject, absolute risk for complication, and aetiological factor of IANI. Statistical tests applied include Mann-Whitney U-test, Chi-squared test, and Fisher's exact test. Women sustaining IANI were more likely older than those having infection, mechanical damage, or failed osseointegration (P < 0.05), while no significant differences emerged in men. Women were more likely at risk for IANI (P < 0.01) or implant malposition (P < 0.05) than men. The results support earlier propositions that women are more vulnerable than men to iatrogenic IANI.

PURPOSE The present study aimed to evaluate which factors were statistically associated with a greater probability of inferior alveolar nerve (IAN) damage during lower third molar surgery. METHODS A prospective observational study was performed at the Oral Surgery Unit of the Umberto I Hospital on 92 patients who underwent surgical extraction of a lower third molar that was radiographically overlapped with the mandibular canal. All surgeries were performed by the same expert surgeon. A principal component analysis and the exact 2-tailed Fisher exact test were used. RESULTS Temporary IAN damage occurred in 10 cases (10.9%). Symptoms lasted from 18 to 180 days (73 ± 49.15). IAN damage was more frequent in difficult and long-lasting surgeries, in the presence of many risk factors and in patients with a reduced maximum mouth opening. CONCLUSION Such factors should be accurately evaluated before surgery to assess and discuss the overall surgical risk of IAN damage with the patient especially when they are over the maximum limit of their significant variability range found in the present study, that is, >12 for difficulty index, >2 for number of orthopantomography risk markers and

Trigeminal neuralgia (TN) is a type of severe paroxysmal neuropathic pain commonly triggered by mild mechanical stimulation in the orofacial area. Piezo2, a mechanically gated ion channel that mediates tactile allodynia in neuropathic pain, can be potentiated by a cyclic adenosine monophosphate (cAMP)-dependent signaling pathway that involves the exchange protein directly activated by cAMP 1 (Epac1). To study whether Piezo2-mediated mechanotransduction contributes to peripheral sensitization in a rat model of TN after trigeminal nerve compression injury, the expression of Piezo2 and activation of cAMP signal-related molecules in the trigeminal ganglion (TG) were detected. Changes in purinergic P2 receptors in the TG were also studied by RNA-seq. The expression of Piezo2, cAMP, and Epac1 in the TG of the TN animals increased after chronic compression of the trigeminal nerve root (CCT) for 21 days, but Piezo2 knockdown by shRNA in the TG attenuated orofacial mechanical allodynia. Purinergic P2 receptors P2X4, P2X7, P2Y1, and P2Y2 were significantly up-regulated after CCT injury. In vitro, Piezo2 expression in TG neurons was significantly increased by exogenous adenosine 5'-triphosphate (ATP) and Ca2+ ionophore ionomycin. ATP pre-treated TG neurons displayed elevated [Ca2+ ]i and faster increase in responding to blockage of Na+ /Ca2+ exchanger by KB-R7943. Furthermore, mechanical stimulation of cultured TG neurons led to sustained elevation in [Ca2+ ]i in ATP pre-treated TG neurons, which is much less in naive TG neurons, or is significantly reduced by Piezo2 inhibitor GsMTx4. These results indicated a pivotal role of Piezo2 in peripheral mechanical allodynia in the rat CCT model. Extracellular ATP, Ca2+ influx, and the cAMP-to-Epac1 signaling pathway synergistically contribute to the pathogenesis and the persistence of mechanical allodynia.

Purpose To assess the long-term recovery of sensation in the lower lip after mandibular resection without reconstruction of the inferior alveolar nerve. Material and Methods Thirty patients who had mandibular resection carried out without reconstruction of the inferior alveolar nerve were examined after an interval ranging from 6 to 33 years. Results Only 1 patient, seen 10 years after resection, was totally numb over the distribution of the inferior alveolar nerve. The other 29 patients had some return of sensation and many had a significant return, though it may take several years to reach the final result. Utilizing the MRC scale 70% of patients achieved S3 (return of superficial cutaneous pain and tactile sensibility without over response) Conclusion This study can serve as a baseline for comparison with patients who have had mandibular resection with reconstruction of the inferior alveolar nerve to assess if this procedure improves the outcomes.

Sensory disturbance in the orofacial region owing to trigeminal nerve injury is caused by dental treatment or accident. Commercially available therapeutics are ineffective for the treatment of sensory disturbance. Additionally, the therapeutic effects of rapamycin, an allosteric inhibitor of mammalian target of rapamycin (mTOR), which negatively regulates autophagy, on the sensory disturbance are not fully investigated. Thus, we investigated the therapeutic effects of rapamycin on the sensory disturbance in the mandibular region caused by inferior alveolar nerve (IAN) transection (IANX) in rats. The expression levels of the phosphorylated p70S6K, a downstream molecule of mTOR, in the proximal and distal stumps of the transected IAN were significantly reduced by rapamycin administration to the injured site. Conversely, the increments of both Beclin 1 and microtubule-associated protein-1 light chain 3-II protein levels in the proximal and distal stumps of the transected IAN was induced by rapamycin administration. Immunohistochemical analyses revealed that Beclin 1 was located in Schwann cells in the proximal stump of the IAN. Accumulation of myelin protein zero and myelin basic protein in the proximal and distal stumps of the IAN was significantly reduced by rapamycin administration. Rapamycin administration facilitated axon regeneration after IANX and increased the number of brain-derived neurotrophic factor positive neurons in the trigeminal ganglion. Thus, recovery from sensory disturbance in the lower lip caused by IANX was markedly facilitated by rapamycin. These findings suggest that rapamycin administration is a promising treatment for the sensory disturbance caused by IANX.

Purpose The nerve sliding technique (NST) was introduced for repairing inferior alveolar nerve (IAN) defect and overcoming the disadvantages of conventional surgical treatment methods such as nerve graft. This study was conducted to identify factors associated with functional sensory recovery (FSR) following inferior alveolar nerve repair using the NST. Patients and Methods This was a retrospective cohort study including all patients who underwent IAN repair using the NST at Seoul National University Dental Hospital, Department of Oral and Maxillofacial Surgery from February 2009 to March 2020. The damaged part of the IAN was excised, and the incisive branch was transected intentionally to perform direct anastomosis without tension. Cox proportional hazard analysis was utilized to determine the relationships between predictor variables (age, gender, chief complaints, preoperative sensory results, duration from injury to repair, length of nerve tissue resected during the procedure, and neuroma formation) and outcome variable (time to FSR). Results The sample was composed of 16 patients with a mean age of 56.1 ± 10.1 years, 25% were males and 75% were females. The mean nerve gap deficit was 7.69 mm (3-15 mm). Ten patients (62.5%) achieved FSR with a median time from operative treatment to FSR of 84.5 days. Dental implant placement was found as the main cause for IAN injury (93.8%) and 56.2% of patients complained of hypoesthesia and dysesthesia. Factors associated with time to FSR at 1 year were age, chief complaint, and early repair. Younger patients (P = .041) and patients without dysesthesia (P = .019) were more likely to achieve FSR. Higher proportion of early repair group achieved FSR, although not statistically significant (P = .068). Conclusions The use of NST in repair of IAN defects up to 15 mm achieved 62.5% FSR. Younger age and absence of dysesthesia were associated with higher FSR.

In the area of craniomaxillofacial trauma, neurosensory disturbances are encountered commonly, especially with regard to the trigeminal and facial nerve systems. This article reviews the specific microanatomy of both cranial nerves V and VII, and evaluates contemporary neurosensory testing, current imaging modalities, and available nerve injury classification systems. In addition, the article proposes treatment paradigms for management of trigeminal and facial nerve injuries, specifically with regard to the craniomaxillofacial trauma setting.

Neurosensory disturbances (NSDs) caused by injury to the trigeminal nerve can affect many aspects of daily life. However, factors affecting the persistence of NSDs in patients with posttraumatic trigeminal neuropathies (PTTNs) remain largely unknown. The identification of such risk factors will allow for the phenotyping of patients with PTTNs, which is crucial for improving treatment strategies. We therefore aimed to identify the prognostic factors of NSD persistence, pain intensity, and quality of life (QoL) in patients with PTTNs and to use these factors to create a prognostic prediction model. We first performed a bivariate analysis using retrospective longitudinal data from 384 patients with NSDs related to posttraumatic injury of the trigeminal nerve (mean follow-up time: 322 ± 302 weeks). Bivariate and multivariate analyses were performed. The multivariable prediction model to predict persistent NSDs was able to identify 76.9% of patients with persistent NSDs, with an excellent level of discrimination (area under the receiver operating characteristic curve: 0.84; sensitivity: 81.8%; specificity: 70.0%). Furthermore, neurosensory recovery was significantly associated with sex; injury caused by local anesthesia, extraction, third molar surgery, or endodontic treatment; and the presence of thermal hyperesthesia. Pain intensity and QoL analysis revealed several factors associated with higher pain levels and poorer QoL. Together, our findings may aid in predicting patient prognosis after dental, oral, and maxillofacial surgery and might lead to personalized treatment options and improved patient outcomes. ispartof: PAIN vol:163 issue:4 pages:E557-E571 ispartof: location:United States status: published

Purpose There is inconsistency in clinical grading of peripheral trigeminal nerve (TN5) injuries that impact patient care. The study goal is to assess the current status of evaluation and classification of TN5 injuries by oral and maxillofacial surgeons (OMSs). Patients and Methods A cross-sectional study design used an electronic survey to 100 selected OMSs to determine their clinical TN5 injury practice, including neurosensory testing, confidence level with current protocols, and evaluation and treatment of a hypothetical TN5 injury case. The target sample was enhanced to reduce type 2 error, assuming prior experience in the diagnosis and management of TN5 injuries. Results The sample was composed of 90 respondents. Nerve injury classification systems used by OMSs include Seddon (44%), Sunderland (70%), and Medical Research Council Scale (31%). Neurosensory testing protocols varied considerably among survey respondents. A sample case for Medical Research Council Scale grading produced inconsistent and inaccurate results. There was no consensus on TN5 injury management, and recommendations for timely nerve repair varied from 1 month to up to 1 year after injury. Half of the respondents stated that OMSs are not adequately prepared to assess inferior alveolar/lingual nerve injuries, and most oral-maxillofacial surgery respondents evaluate fewer than 10 TN5 injuries each year. Most OMSs (92%) have had a temporary inferior alveolar/lingual nerve injury, while 54% have had a permanent injury; of which, 21% required microsurgical repair. The majority of OMSs (74%) believed that a uniform TN5 injury classification system is needed. Conclusions Within the oral-maxillofacial surgery target group experienced in evaluation of TN5 injuries, respondents do not feel confident in the assessment of these injuries. There is inconsistency in evaluation methods, and there is agreement that a unified classification system is needed for more efficient patient evaluation and reporting of outcomes in the literature. The Medical Research Council Scale and clinical neurosensory testing is preferred for evaluation of TN5 injuries.

Background 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. Methods 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 6 months follow-up were included. Results 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. Conclusions 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.

Purpose Evidence shows that low-level laser therapy (LLLT) may shorten the recovery time of healing wounds. This study sought to assess the effect of LLLT on the recovery time of neurosensory deficits after Le Fort I osteotomy and bilateral sagittal split osteotomy using the blink reflex. Methods This randomized double-blind clinical trial evaluated 12 patients undergoing orthognathic surgery of the maxilla/mandible. One random quadrant of the maxilla/mandible underwent 810 nm gallium-aluminum-arsenide laser (infrared spectrum, 200 mW, 12 J/cm2, 60-second irradiation time of each point, continuous-wave mode), while the laser handpiece was used in off mode for the other quadrant, postoperatively. The patients underwent LLLT at 1, 5, 10, and 14 days, postoperatively. The blink test was performed to assess the function of the trigeminal nerve, and the 2-point discrimination (TPD) test was performed to assess the recovery of the inferior alveolar nerve (IAN) and the infraorbital nerves at 30 and 90 days, postoperatively. Data were analyzed using the Mann-Whitney U test (alpha = 0.05). Results Six women and 6 men were evaluated (mean age = 23.41 ± 5.03 years). Both groups showed significant improvement in function of the IAN and infraorbital nerves, postoperatively in blink reflex test (P Conclusions LLLT with 810-nm diode laser can accelerate the recovery from paresthesia after orthognathic surgery. The blink reflex can be used as a quantitative index for neurosensory assessment in line with subjective clinical tests such as the TPD test.

Post-traumatic trigeminal neuropathy (PTTN) is a known complication of common oral and maxillofacial procedures. The burden on the patient and society is often underestimated. This retrospective study included 29 patients with PTTN who underwent surgical treatment. Symptoms were differentiated, pre- and postoperatively, into neuropathic discomfort and loss of perceptive function. Clinical and patient-reported outcomes were recorded. The Brief Pain Inventory questionnaire was completed at the last follow-up. The effect of different variables was evaluated through subgroup analysis. The mean time interval between injury and surgery was 19 weeks. Overall, 20 patients (69%) showed improvement during a mean follow-up of 49 months. Neuropathic pain decreased in most patients (13/18; 72%) and two patients became pain-free. However, 16 patients reported persistent pain on the Brief Pain Inventory questionnaire. Medication use decreased postoperatively. Subgroup analysis showed a positive association between improvement and male sex (Fisher's exact test, P=0.033), and between improvement and the buccal fat nerve wrapping procedure (Fisher's exact test, P=0.02). In conclusion, surgery showed substantial benefit in the treatment of PTTN, even when neuropathic pain was present. The effect of different variables and the potential of buccal fat nerve wrapping should be evaluated further in future research. ispartof: INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY vol:50 issue:1 pages:132-138 ispartof: location:Denmark status: published

Trigeminal nerve branches are never far from the operating field of the oral and maxillofacial surgeon. Increasingly the surgeon is required to provide accurate diagnosis and grading of trigeminal nerve injury, and surgical management by oral and maxillofacial surgeons will become common. Although trauma and ablative procedures for head and neck pathology can cause injuries, dentoalveolar surgical procedures remain an important cause of injury to the fifth cranial nerve, with the third division being the main branch affected. Oral and maxillofacial surgeons should be aware of strategies of avoiding iatrogenic injury, and know when referral and surgical management are appropriate.

Coronectomy is an alternative surgical technique for the management of high-risk third molars. It involves the removal of the crown of a tooth and the deliberate retention of the roots, thereby avoiding injury to the inferior alveolar nerve (IAN). Previous studies have suggested that it reduces the risk of nerve injury when compared with surgical extraction. The purpose of this study was to systematically review the incidence of complications following coronectomy such as IAN injury, pain, dry socket, infection, root migration, and need for re-operation. A comparative cost analysis of coronectomy and surgical extraction was done based on the results of the review. This provides an insight into the economic implications of the two procedures. A search through the MEDLINE database via Ovid, PubMed, Scopus, EMBASE via Ovid, and Web of Science, was carried out to extract randomised and non-randomised controlled trials. Four studies fulfilled the inclusion criteria. A meta-analysis was conducted to measure the overall effect of each outcome. The pooled odds ratio (OR) for IAN injury was 0.16 (95% CI 0.01 to 0.39). Coronectomy reduced this risk by 84%. Dry socket may occur less frequently following coronectomy whereas infection did not show a higher incidence with either intervention. Root migration was found to occur in 13%-85% of cases and the average incidence of re-operation was 2.2%. The ratio of the average costs was 1.12 favouring coronectomy if cone-beam computed tomography (CBCT) was not done prior to the procedure. If a scan was taken routinely for coronectomy, the cost ratio marginally favoured extraction. Coronectomy reduced the risk of nerve injury in high-risk third molars. Definitive conclusions, however, cannot be made for outcomes such as the need for re-operation, which may alter the cost ratio of coronectomy:extraction, as higher quality studies with longer follow-up are needed.

Objective The aim of this study was to evaluate the relationship between neurosensory disturbance (NSD) and the different types of bilateral sagittal split osteotomy (BSSO) lingual fracture created. Study Design The study group consisted of 45 patients with mandibular deformities (90 sides; 14 males and 31 females). Computed tomography (CT) scans were obtained preoperatively and 1 week postoperatively. All patients were divided into lingual fracture line groups on the basis of their postoperative scans. NSD was tested preoperatively and 1, 3, and 12 months postoperatively by using a sensory touch Semmes-Weinstein (SW) test and the 2-point discrimination (TPD) test. Results Patients were divided into 2 groups on the basis of their lingual fracture lines after mandibular BSSO; among the 45 patients, 39 sides (43.3%) had short-splits, and 51 sides (56.7%) had long-splits. The short-split group was less affected at all tested times, and the difference between the 2 groups was significant 1 month postoperatively on TPD test but not at other times on the both tests. Conclusions The split type did not affect the NSD incidence at 3 and 12 months postoperatively.

To the best of our knowledge there are no guidelines regarding the surgical management of dental implant-related injuries to the mandibular nerve. This review aims to investigate the success of different surgical interventions. Neurosensory injury to the mandibular branch of the trigeminal nerve can occur during administration of local anaesthetic, elevation of the flap, preparation for osteotomy, and placement of the implant. Surgical interventions include extraction of the implant, external decompression, internal neurolysis, excision of a neuroma, neurorrhaphy, nerve grafting, and low-level laser therapy. The following electronic databases were searched: MEDLINE, EMBASE, and the Cochrane Library. Primary outcome measures included patient-reported outcomes such as pain and altered sensation. A total of 185 publications were obtained, of which 21 were included in the qualitative synthesis (2 randomised controlled trials (RCT), 9 controlled cohort studies, and 10 case reports/series). They were all screened in consideration of the exclusion criteria and appraised using the Cochrane risk of bias tool, the Newcastle Ottawa scale, and the modified Newcastle Ottawa scale. Results were triangulated to evaluate their level of agreement. The extraction of dental implants less than 36hours after injury to the mandibular nerve results in the most successful resolution of neurosensory dysfunction. Various microsurgical techniques have shown less success in obtaining neurosensory recovery than extraction of the implant. However, microsurgery is worthwhile, as it improves neurosensory dysfunction and reduces dysaesthesia in the majority of patients. Direct suturing and external decompression can result in good neurosensory recovery, and nerve grafts are also successful whenever tension-free direct suturing is not possible. Low-level laser therapy has been shown to achieve some neurosensory improvement.

The infraorbital nerve is a branch of the trigeminal nerve. Injury to the infraorbital nerve can be caused by trauma, including various facial fractures. Due to this nerve injury, patients complain of numbness and pain in the entire cheek, the ala of nose, and upper lip. In general, spontaneous sensory recovery is expected after decompressive surgery. If nerve transection is confirmed, however, neurorrhaphy is typically performed. Here, we present a case in which microsurgery was not performed in a patient with Sunderland grade V avulsion injury of the infraorbital nerve due to a facial bone fracture. Gradual nerve function recovery was confirmed to be possible with conservative treatment and rehabilitation alone. These findings suggest that the nerve function recovery can be expected with conservative treatment, even for severe nerve injury for which microsurgery cannot be considered.

Objectives To investigate the thermal pain phenotypes using QST in patients with unilateral trigeminal nerve injury and to explore whether these different thermal pain phenotypes are associated with clinical and psychophysical characteristics. Methods This retrospective study included 84 patients diagnosed with posttraumatic trigeminal neuropathy involving inferior alveolar nerve (IAN) and lingual nerve (LN). Data on clinical characteristics, subjective symptoms including hypoesthesia, dysesthesia, and allodynia, and objective signs using thermal QST were collected and explored. Results Three heat (heat hypoalgesia, heat hyperalgesia, and within normal range) and cold pain phenotypes (cold hypoalgesia, cold hyperalgesia, and within normal ranges) were identified, respectively. Thermal hypoalgesia was more frequently observed than thermal hyperalgesia. Heat hypoalgesia regardless of cold pain abnormalities appears to be associated with subjective negative symptoms, while thermal hyperalgesia seems to have little relationship with negative and positive symptoms. Thermal pain phenotypes were associated with loss of innocuous thermal sensation. Unlike heat pain phenotypes, cold pain phenotypes differed between IAN injury and LN injury. Conclusion The thermal pain phenotypes identified in this study seem to be related to clinical and psychophysical findings differently. These results would be a good starting point for assessing posttraumatic trigeminal neuropathy and interpreting the thermal QST results.

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

Painful traumatic trigeminal neuropathy (PTTN) may occur following major craniofacial or oral trauma, or may be subsequent to relatively minor dental interventions. Following injury, pain may originate from a peripheral nerve, a ganglion, or from the central nervous system. In this review, we focus on molecular mechanisms of pain resulting from injury to the peripheral branch of the trigeminal nerve. This syndrome has been termed painful traumatic trigeminal neuropathy (PTTN) by the International Headache Society and replaces previous terms including atypical odontalgia, deafferentation pain, traumatic neuropathy and phantom toothache. We emphasize the scientific evidence supporting the events purported to lead to PTTN by reviewing the pathophysiology of PTTN based on relevant animal models. Additionally, we briefly overview clinical correlates and pathophysiological manifestations of PTTN.

The purpose of this study was to characterize the patterns of lingual split and lateral bone cut end (LBCE) after bilateral sagittal split osteotomy (BSSO) in patients and identify their associations with postoperative neurosensory disturbance. This retrospective cohort study recruited 273 patients with skeletal malocclusion who received BSSO. The postoperative cone beam computed tomography data were reconstructed to three-dimensionally view the patterns of lingual split and LBCE. Associations between lingual split and LBCE and their effects on neurosensory disturbance in the lower lip and chin were determined. Six types of lingual split and three types of LBCE were defined based on three-dimensional images. Type I lingual split as a vertical fracture line to the inferior mandibular border was the most common (40.29%). Inferior LBCE was the most prevalent, followed by lingual and buccal types. Significant associations among lingual split, LBCE and skeletal deformities were found (P 0.05). However, patterns of lingual split and LBCE were not associated with the incidence of neurosensory disturbance. Patterns of lingual split after BSSO significantly associated with types of LBCE and dentomaxillofacial deformities, but not with postoperative neurosensory disturbance.

Purpose This study aimed to assess the factors that can possibly affect the positioning of the inferior alveolar nerve (IAN) in the proximal or distal segment following sagittal split osteotomy (SSO). Materials and methods This was a prospective cohort study. The patients were assigned according to the position of the IAN: the IAN was attached to the buccal plate in group 1 (27 SSOs), while it was in the distal segment in group 2 (83 SSOs). Results The mean of the buccolingual thickness of the proximal segment at the vertical cut of the osteotomy (BLTP) was 5.0 ± 0.62 mm in group 1 and 4.16 ± 0.72 mm in group 2. The mean of the distance between the IAN and the external cortical bone at the distal of the second molar before the osteotomy (IANB) was 0.5 ± 0.24 mm in group 1 and 1.24 ± 0.45 mm in group 2. There were significant differences for the mean BLTP and IANB between the two groups (P = 0.001). Conclusion It seems that the thickness of the buccal plate of the proximal segment, the distance from the IAN to the external cortical bone, the osteotomy technique, and the presence or absence of impacted third molars may be associated with the positioning of the IAN following SSO.

This survey of expert opinion regarding the management of mandibular third molar (M3M) impaction and its clinical sequelae was circulated to all members of the British Association of Oral and Maxillofacial Surgeons (BAOMS). It was completed by 289 clinicians who reported treating 60003 patients annually. Respondents included 199 (69%) specialists and 58 (20%) primary care clinicians. Most (99%) of the clinicians treated at least one M3M with complete surgical removal (CSR) annually. Only 69% performed one or more coronectomies (COR). Advocates of coronectomy reported lower rates of inferior alveolar nerve (IAN) injury, but IAN, lingual nerve, and adjacent second molar damage were rare, occurring in less than 0.5% of cases, with small differences between the COR and CSR groups. Although these differences are not statistically significant, they are likely to be clinically important. Also, the COR group would have comprised mainly high-risk teeth, while the CSR group would include many teeth at low risk of complications. This might have skewed the results. Those clinicians performing no coronectomies cited three main reasons for being low adopters of COR: the lack of irrefutable evidence to support its benefit, the increased need for a second operation, and more non-IAN complications. Although COR may prevent permanent IAN damage in high-risk cases, this paper highlights clinicians' views that there is a gap in evidence and knowledge to support COR. As a result, 47% of the clinicians surveyed recommended, and were prepared to participate in, further studies to determine the effectiveness and safety of COR.

This study analyzes the risk factors associated with the incidences of inferior alveolar nerve (IAN) injury after surgical removal of impacted mandibular third molar (IMTM) and to evaluate the contribution of these risk factors to postoperative neurosensory deficits.An exhaustive literature search has been carried out in the COCHRANE library and PubMed electronic databases from January 1990 to March 2019 supplemented by manual searching to identify the related studies. Twenty-three studies out of 693 articles from the initial search were finally included, which summed up a total of 26,427 patients (44,171 teeth).Our results have been compared with other current available papers in the literature review that obtained similar outcomes. Among 44,171 IMTM extractions performed by various grades of operators, 1.20% developed transient IAN deficit and 0.28% developed permanent IAN deficit respectively. Depth of impaction (P0.001), contact between mandibular canal (MC) and IMTM (P0.001), surgical technique (P0.001), intra-operative nerve exposure (P0.001), and surgeon's experience (P0.001) were statistically significant as contributing risk factors of IAN deficits.Radiographic findings, such as depth of impaction, proximity of the tooth to the mandibular canal, surgical technique, intra-operative nerve exposure, and surgeon's experience were high risk factors of IAN deficit after surgical removal of IMTMs.

PURPOSE Inferior alveolar neurosensory disturbance (IAND) is the most common complication of bilateral sagittal split osteotomy (BSSO). The aim of the present study was to evaluate IAND with subjective tests postoperatively and assess the relationship between three-dimensional measurements of the mandibular canal (MC) and IAND. METHODS Eighteen patients (Mean age: 24.05 ± 5.85 years) treated with BSSO were retrieved from the archive. Subjective tests (light touch, tactile sensitivity, 2-point discrimination, brush-stroke directional discrimination, sharp/blunt discrimination, dental vitality, questionnaire) and three-dimensional measurements related to MC and fixation screws were done postoperatively (on average 20.43 ± 8.76 months after surgery). Statistical significance was set at P

During root canal treatments, calcium hydroxide can extrude through the apex causing chemical, mechanical, and/or thermal injuries to the inferior alveolar nerve, which can lead to neurological disorders. Unfortunately, dental practitioner negligence can produce this potentially life-changing injury that can compromise the patient's life. The aim of this study is present a case of dental negligence by calcium hydroxide extrusion causing inferior alveolar nerve damage, discuss the methods of prevention, and characterize the medico-legal aspects of complication.

Objectives This study aimed to quantitatively compare the somatosensory function changes of inferior alveolar nerve (IAN) after mandibular third molar extraction with a surgery protocol of coronectomy, as opposed to the conventional method. Materials and methods Patients with a lower third molar directly contacting IAN were recruited and assigned either to a test group (coronectomy group) or a control group (conventional extraction). A standardized quantitative sensory testing (QST) battery was performed for four times: one week before surgery and the second, seventh, and 28th days after surgery. Z-scores and the loss/gain coding system were applied for each participant. Results A total of 140 molars (test group: n = 91, control group: n = 49) were enrolled. The sensitivity of the mechanical detection threshold (MDT) and pressure pain threshold (PPT) significantly increased after surgery more than before surgery in both groups (P ≤ 0.001). After the surgery, the sensitivities of the cold detection threshold (CDT), cold pain threshold (CPT), and heat pain threshold (HPT) were significantly higher in the test group than in the control group (P ≤ 0.027). The risk of IANI was significantly larger (P = 0.041) in the test group than in the control group. Conclusions QST was a sensitive way to detect somatosensory abnormalities even with no subjective complaint caused by surgery. Coronectomy had less influence on IAN function than conventional total extraction. Clinical relevance The somatosensory function changes after mandibular third molar extraction were quantitatively studied, and coronectomy was proved a reliable alternation to reduce IAN injury rate.

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 The incidence of adverse sequelae related to trauma of cranial nerve V2 (V2) and the Vidian nerve (VN) during endoscopic pterygoid recess repair (PRR) of lateral sphenoid encephalocele is insufficiently reported in the medical literature. As part of our quality assessment and improvement program we sought to analyze the incidence and severity of V2 and VN injury during a 9-year experience (2010-2018) with PRR. Methods Hypoesthesia, paresthesia, and dry eye and their impact on patient quality of life were sought through chart review and a self-reported 0 to 5 Likert scale for each symptom. Results Thirty-five patients underwent repair of spontaneous cerebrospinal-fluid (CSF) rhinorrhea, with 11 consecutive patients undergoing endoscopic PRR. Mean follow-up for PRR was 32.5 months (range, 2.4 to 103.3 months). Although definitive management resulted in 100% success, 1 required secondary treatment. Eight patients were available for long-term follow-up (72.7%) and completed a symptom severity questionnaire using a Likert-scale. All patients observed either hypoesthesia, paresthesia, or dry eye of varying gradation (scale, 0 to 5). None described disabling symptoms, and some reported gradual improvement. Numbness, paresthesia, and dry eye were reported by 6 of 8 (75%), 5 of 8 (62.5%), and 4 of 8 (50%) patients, respectively. The mean Likert score among the 8 patients who completed this questionnaire noticing hypoesthesia, paresthesia, and dry eye was 2.6, 1.3, and 1.8, respectively. Conclusion Meticulous surgical technique is paramount for successful PRR and minimizing nerve injury, yet the anatomic variation of the lateral pterygoid recess can be challenging, and neural injury is a real risk. Preoperatively, patients should be counseled that although V2 or VN injury is common, most patients describe resulting symptoms to be rarely bothersome.

Objective: Painful post-traumatic trigeminal neuropathy (PTTN) is a clinical pain syndrome that occurs due to injuries to the peripheral branches of the trigeminal nerve and is characterized by a d...

Since MRI using dedicated imaging sequences has recently shown promising results in direct visualization of the inferior alveolar nerve (IAN) and the lingual nerve (LN) with high spatial resolution, the aim of this study was to generate suitable standard specifications to reliably depict the IAN and LN in MRI and to delineate the anatomy and its variants of these nerves in healthy subjects. Thirty healthy volunteers were examined on a 3-T scanner (Elition, Philips Healthcare, Best, the Netherlands). The sequence protocol consisted of 3D STIR, 3D DESS, and 3D T1 FFE “black bone” sequences. The study reconfirmed a good feasibility of direct visualization of proximal and peripheral portions of the IAN and of the proximal course of the LN. The STIR sequence showed the highest apparent signal to noise ratio (aSNR) and best apparent nerve-muscle contrast to noise ratio (aNMCNR) for IAN and for the LN. The applied MRI sequences allowed to differentiate the tissue composition of the neurovascular bundle inside the mandibular canal. Dedicated MRI sequence protocols proved effectively to detect the IAN and LN and their course in healthy volunteers. The tissue composition of the mandibular neurovascular bundle was conclusively distinguishable as was the varying topography inside multiple bony channels. The presented data on the precise and valid visualization of the IAN and LN have clinical implications in respect to local anesthesia prior to dental treatments in the mandible but also regarding surgical procedures and implant insertion in the molar region.

There are multiple reasons for failure of full maxillary dentures. It is necessary for clinicians to consider the rationale behind the failure of the prosthesis before remaking a maxillary full denture. Diagnostic categories related to pertinent maxillofacial and oral neuropathies and psychosocial issues are also discussed. Here, we present a case with a natural history that supported a diagnosis of peripheral painful traumatic trigeminal neuropathy (PPTTN). Furthermore, the clinical oral examination revealed findings that were consistent with atrophic glossitis, necessitating an investigation of diagnoses of nutritional deficiency-induced neuropathy and/or oral candidiasis.

Inferior alveolar nerve (IAN) damage is a rare but recognised complication of dental procedures including third molar surgery, implant surgery, endodontic treatment and local anaesthetic injections. However, it is rarely caused by orthodontic tooth movement. This report highlights a case of temporary IAN anaesthesia to the right mental region, which was likely to have occurred secondary to the orthodontic uprighting of a lingually tilted molar using a high strength arch wire. Immediate deactivation of the appliance and an acute reducing dose of systemic steroids resulted in complete resolution of symptoms. To the best of the author’s knowledge, there have been seven previously described cases of IAN paraesthesia but no cases reporting IAN anaesthesia secondary to orthodontic fixed-appliance treatment. This case highlights the importance of dentists practising orthodontics to have an awareness of the clinical and radiographic signs that may indicate a high-risk case requiring appropriate referral for cone beam imaging and careful orthodontic planning. Furthermore, this case emphasises the need to warn high-risk patients of the symptoms of this rare complication and how it may be managed. This will ultimately help to minimise the risk of litigation and optimise patient experience and care.

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. 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. 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. 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.

Background Neurosensory changes are frequently observed in the patients with mid-face fractures, and these symptoms are often caused by infraorbital nerve (ION) damage. Although ION damage is a relatively common phenomenon, there are no established and objective methods to evaluate it. The aim of this study was to test whether trigeminal somatosensory evoked potential (TSEP) could be used as a prognostic predictor of ION damage and TSEP testing was an objective method to evaluate ION injury. Methods In this prospective TSEP study, 48 patients with unilateral mid-face fracture (only unilateral blow out fracture and unilateral zygomaticomaxillary fracture were included) and potential ION damages were enrolled. Both sides of the face were examined with TSEP and the non-traumatized side of the face was used as control. We calculated the latency difference between the affected and the unaffected sides. Results Twenty-four patients recovered within 3 months, and 21 patients took more than 3 months to recover. The average latency difference between the affected side and unaffected side was 1.4 and 4.1 ms for the group that recovered within 3 months and the group that recovered after 3 months, respectively. Conclusion Patients who suffered ION damage showed prolonged latency when examined using the TSEP test. TSEP is an effective tool for evaluation of nerve injury and predicting the recovery of patients with ION damage.

The aim of this study was to find out if juxta-apical radiolucency (JAR) is a reliable risk factor for injury to the inferior alveolar nerve (IAN) during removal of lower third molars. We designed a cohort study of patients whose dental panoramic tomograms (DPT) had shown JAR before complete removal of lower wisdom teeth. The outcome variable was postoperative permanent neurosensory disturbance of the IAN. A total of 39 patients (50 lower third molars) were identified and screened for permanent neurosensory disturbance. None reported any permanently altered sensation 18 months after the operation. Based on our group, the presence of JAR does not seem to be a reliable predictor of the risk of permanent injury to the IAN during removal of lower third molars.

Objective Dental treatment and orofacial surgeries may induce chronic neuropathic orofacial pain (CNOP). This kind of pain affects adaptability to environmental changes in both model animals and humans. Part of the adaptation process depends on the ability to distinguish between familiar and novel stimuli. CNOP induces novelty seeking behaviour as a deficit in environmental adaptation. Alternatively, novelty seeking is a sign for susceptibility to the development of substance abuse. Evidence shows that CNOP leads to alcoholism in animal models. The behavioural relationship between CNOP, novelty seeking behaviour and substance abuse is unknown. In this article, we investigate if CNOP produces an increase in novelty seeking and leads to increasing ethanol intake. Design Firstly, we used mental nerve injury as a neuropathic orofacial pain model to evaluate both thermal and mechanical allodynia. We used the novel recognition task to determine novelty seeking behaviour and the drink in darkness protocol to assess ethanol intake. Results Our results show that mental nerve constriction increases novelty seeking behaviour (p = 0.01) and correlates with ethanol binge consumption (r2 = 0.68, p = 0.0008). Conclusions The present study demonstrates, for the first time, that trigeminal nerve injury, which induces CNOP, is enough to provide novelty seeking behaviour and lead to increasing ethanol intake. The increase of novelty seeking behaviour can serve as a predictor of risk of developing substance abuse. The treatment of CNOP involves a high risk of producing addiction. The level of novelty seeking evaluation in patients with neuropathic pain before treatment is critical.

Our aim was to evaluate neurosensory symptoms after lateralisation of the inferior alveolar nerve (IAN). We studied a retrospective case series with one-year follow up that included 139 procedures in 123 patients. After the IAN had been located it was deflected from the mandibular body and the implant placed. Sensitivity was mapped 24 hours, one month, six months, and one year after the intervention by gently pressing the skin and lips with the tip of a probe. A total of 337 implants were placed in 123 patients aged between 44 and 68 years. There were 33 men and 90 women and they all recovered. The IAN was mobilised by one of two procedures, one that involves the nerve directly (transposition) and one that does not (lateralisation). During lateralisation the nerve is deflected laterally through a mandibular osteotomy, while the mental nerve and mental foramen are not manipulated. The resulting hypoaesthetic area was drawn on a graph to assess its extension. Although different techniques are available for placing implants in atrophic jaws, mobilisation of the IAN is indicated in certain cases in which other techniques are not feasible or have a high risk of complications.

Currently, limited information regarding the role of calcitonin gene-related peptide (CGRP) in neuropathic pain is available. Intracerebroventricular administrations of an anti-CGRP antibody were performed in rats with infraorbital nerve ligation. Anti-CGRP antibody administration attenuated mechanical and heat hypersensitivities induced by nerve ligation and decreased the phosphorylated extracellular signal-regulated kinase expression levels in the trigeminal spinal subnucleus caudalis (Vc) following mechanical or heat stimulation. An increased CGRP immunoreactivity in the Vc appeared after nerve ligation. A decreased CGRP immunoreactivity resulted from anti-CGRP antibody administration. Our findings suggest that anti-CGRP antibody administration attenuates the symptoms of trigeminal neuropathic pain by acting on CGRP in the Vc.

Investigation in Saudi Arabia or the Arab Gulf States to assess the unfavorable impacts of the bilateral sagittal split osteotomy (BSSO) is non-existent, so questions have been raised about the success rate of this operation and the frequency of unwilling outcome. To address these worries, we directed a case series study to evaluate the hypoesthesia, a type of neurosensory deficit (NSD) of the inferior alveolar nerve (IAN) after BSSO, and if the hypoesthesia outcome will improve if the surgeries performed by a single surgeon. This was a prospective case series study for the patient who underwent BSSO in a medical complex that is considered one of the largest in Saudi Arabia (Riyadh). The inclusion criteria include patient aged 18–40 years, any gender, and American Society of Anesthesiologists (ASA) class I. They will undergo BSSO for either mandibular, retrognathia, prognathic, or to follow the maxilla. The outcome will be measured after evaluating the neurosensory by four means light touch (LT), pinprick (PP), 2-point discrimination (2PD), and thermal sensations (TT) in four repeated measurements (preoperatively, 1 week, 1 month, 3 months postoperatively) as the primary outcome. Other confounding factors were the secondary outcome (age, gender, visualization of the I.A.N, the type of mandibular movement, split favorability, mandibular canal location, and patient reports about paresthesia or dysesthesia on any given side); these data analyses were carried out using SPSS ver. 25 data processing software. The nerve was visible in 93% of cases. During the operation, none of the nerves was transected. Hypoesthesia on the first follow-up was 94% of cases for LT, 92% for PP, 82% for TT, and 100% for the 2PD. On the last follow-up, the patients still had hypoesthesia for the LT 51%, PP 35%, TT41%, and 2PD 55%; age and sex did not significantly affect hypoesthesia outcomes. Nerve visibility and inferior alveolar nerve canal (IAC) distance did not influence the results. The level of confidence for all tests was set at p

The oral cavity is a portal into the digestive system, which exhibits unique sensory properties. Like facial skin, the oral mucosa needs to be exquisitely sensitive and selective, in order to detect harmful toxins versus edible food. Chemosensation and somatosensation by multiple receptors, including transient receptor potential channels, are well-developed to meet these needs. In contrast to facial skin, however, the oral mucosa rarely exhibits itch responses. Like the gut, the oral cavity performs mechanical and chemical digestion. Therefore, the oral mucosa needs to be insensitive, to some degree, in order to endure noxious irritation. Persistent pain from the oral mucosa is often due to ulcers, involving both tissue injury and infection. Trigeminal nerve injury and trigeminal neuralgia produce intractable pain in the orofacial skin and the oral mucosa, through mechanisms distinct from those seen in the spinal area, which is particularly difficult to predict or treat. The diagnosis and treatment of idiopathic chronic pain, such as atypical odontalgia (idiopathic painful trigeminal neuropathy or post-traumatic trigeminal neuropathy) and burning mouth syndrome, remain especially challenging. The central integration of gustatory inputs might modulate chronic oral and facial pain. A lack of pain in chronic inflammation inside the oral cavity, such as chronic periodontitis, involves the specialized functioning of oral bacteria. A more detailed understanding of the unique neurobiology of pain from the orofacial skin and the oral mucosa should help us develop novel methods for better treating persistent orofacial pain.

Introduction This study aimed to construct a predictive scoring system for inferior alveolar nerve injury (IANI) following lower third molar (LM3) surgery based on cone-beam computed tomography (CBCT) images. Material and Methods Of the 1573 patients who underwent LM3 removal following the CBCT, 39 with IANI and 457 randomly selected patients without IANI were enrolled. We collected information regarding the demographic characteristics of the patients, surgical situations, and inferior alveolar canal (IAC)-related CBCT factors. The association with IANI-risk was evaluated with a backward stepwise logistic regression model as per the Akaike information criterion. Scoring models’ abilities of discrimination (area under the curve) and calibration (Hosmer–Lemeshow test and calibration plots) were assessed, followed by evaluation of the clinical usefulness using decision curve analysis. Results As per the multivariate analysis, the coronal positioned IAC on the enlarged root (odds ratio [OR], 3.78; P = 0.001), the length of perforated IAC (>3.4 mm) (OR, 3.05; P = 0.012), lingual/inter-radicular position of the IAC (OR, 3.96; P = 0.001), multiple roots closed to the perforated IAC (OR, 2.78; P = 0.025), and age >30 y (OR, 2.31; P = 0.076) were identified in the extended scoring model ranging from 0 to 12. This model was compared with our previously constructed baseline model that involved the latter three variables mentioned above, resulting in superior performance than that of the baseline model. Conclusion The extended model would be a useful tool for reliable determination of the preoperative probability of IANI.

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.

Background: Injury of the trigeminal nerve in oral and maxillofacial surgery can occur. Schwann cell mitochondria are regulators in the development, maintenance and regeneration of peripheral nerve axons. Evidence shows that after the nerve injury, mitochondrial bioenergetic dysfunction occurs and is associated with pain, neuropathy and nerve regeneration deficit. A challenge for research is to individuate new therapies able to normalise mitochondrial and energetic metabolism to aid nerve recovery after damage. Photobiomodulation therapy can be an interesting candidate, because it is a technique involving cell manipulation through the photonic energy of a non-ionising light source (visible and NIR light), which produces a nonthermal therapeutic effect on the stressed tissue. Methods: The review was based on the following questions: (1) Can photo-biomodulation by red and NIR light affect mitochondrial bioenergetics? (2) Can photobiomodulation support damage to the trigeminal nerve branches? (preclinical and clinical studies), and, if yes, (3) What is the best photobiomodulatory therapy for the recovery of the trigeminal nerve branches? The papers were searched using the PubMed, Scopus and Cochrane databases. This review followed the ARRIVE-2.0, PRISMA and Cochrane RoB-2 guidelines. Results and conclusions: The reliability of photobiomodulatory event strongly bases on biological and physical-chemical evidence. Its principal player is the mitochondrion, whether its cytochromes are directly involved as a photoacceptor or indirectly through a vibrational and energetic variation of bound water: water as the photoacceptor. The 808-nm and 100 J/cm2 (0.07 W; 2.5 W/cm2; pulsed 50 Hz; 27 J per point; 80 s) on rats and 800-nm and 0.2 W/cm2 (0.2 W; 12 J/cm2; 12 J per point; 60 s, CW) on humans resulted as trustworthy therapies, which could be supported by extensive studies.

Neurosensory disturbance of the inferior alveolar nerve (IAN) is an adverse effect associated with sagittal split osteotomies (SSO). The purpose of this work was to evaluate neurosensory recovery of the IAN when SSOs were performed with piezoelectric (PZ) versus reciprocating (RP) saws. This was a prospective split-mouth study of patients undergoing bilateral SSO using a PZ saw on one side and an RP saw on the other. The primary outcome of interest was neurosensory recovery, as assessed using the functional sensory recovery (FSR) scale defined by the UK Medical Research Council. Descriptive, bivariate, and regression statistics were computed. Twenty patients (40 SSOs) with a mean age of 19.9 ± 3.2 years were included. The mean mandibular movement did not differ significantly (P = 0.50) between the PZ and RP groups. All patients achieved FSR within 1 year of surgery (range 34–249 days). The median time to FSR overall was comparable between the PZ and RP groups (94.5 days and 101.5 days, respectively; P = 0.20). However, at the time FSR was achieved, PZ SSO sites were more likely to have higher neurosensory scores when compared to RP SSO sites (hazard ratio 2.3, 95% confidence interval 1.1–4.9, P = 0.04).

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.

BACKGROUND: Neurosensory impairment is a common complication following inferior alveolar nerve (IAN) damage. OBJECTIVE: To document and report the various causes, diagnosis, and management of IAN damage secondary to orthodontic treatment. METHODS: An electronic search for studies that reported IAN damage in patients undergoing orthodontic treatment was performed up to July 15, 2020 using MEDLINE, Embase, and PubMed databases. Descriptive analyses and linear regression model were performed. RESULTS: A total of 15 case reports were identified including 16 patients with an overall mean age of 23.3. All the included studies reported temporary sensory alterations which manifested as anesthesia (19%, n = 3), paresthesia (75%, n = 12), or combined (6%, n = 1). The majority of cases managed by stopping the orthodontic force (75%, n = 12), followed by appliance adjustments (19%, n = 3), providing a bite plate (13%, n = 2), and/or providing pharmacological management (38%, n = 6). Full recovery median duration reported in all cases following the aforementioned managements was 17.5 days. CONCLUSIONS: IAN damage secondary to orthodontic treatment is emerging in the literature in recent years. Identifying high risk patients with close proximity to the IAN canal is a must to formulate a proper treatment plan to avoid such complications.