Benefits of Coronectomy in Lower Third Molar Surgery: A Systematic Review and Meta-analysis.

PURPOSE: The purpose of this study was to measure and compare coronectomy versus extraction in patients at increased risk for inferior alveolar nerve (IAN) injuries associated with third molar removal in terms of IAN injury and other complications. METHODS: The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist. We conducted a comprehensive literature search across six databases and the gray literature from July 15 to August 01, 2022. We employed Rayyan software to identify and remove duplicate articles to ensure data integrity. Our research followed the strategy patient (P), intervention (I), comparison (C), outcome (O), and study (S): (P) patients needing lower third molar surgery at higher risk of IAN injury; (I) surgery options, coronectomy or complete extraction; (C) comparisons included reduced risks of nerve injuries, postoperative complications (pain, infection, alveolitis), and increased risks of reoperation, root migration, and extraction; (O) desired outcomes were preventing nerve injuries and reducing other surgical complications; and (S) observational study designs (cohort, case-control). Excluded from consideration were studies involving teeth other than lower third molars, as well as reviews, letters, conference summaries, and personal opinions. To gauge the certainty of evidence, we employed the Grading of Recommendation, Assessment, Development, and Evaluation instrument, selecting the most current papers with the highest levels of evidence for inclusion. The primary outcome variable of our study centered on evaluating the incidence of IAN injury, and secondly, the lingual nerve (LN) injury, the postoperative pain, infection, localized alveolitis, the necessity for surgical reintervention, root migration, and extraction. These assessments were carried out with respect to their chosen operative technique for managing third molars, either coronectomy or extraction, as predictor variables. We also considered covariates such as age, gender, and the presence of systemic diseases in our analysis to account for potential confounding factors. The pooled data underwent rigorous analysis utilizing an inverse variance method with both random and fixed effect models by the "metabin" function in the R program's meta-package. Additionally, we assessed the risk of bias in the selected studies by utilizing the Joanna Briggs Institute's Critical Appraisal Checklist for Studies Reporting Prevalence Data and the Critical Appraisal Checklist for Case Reports. RESULTS: Of the 1,017 articles found, after applying the inclusion and exclusion criteria, 42 were included in this study (29 cohort and 13 case-control studies), including 3,095 patients from 18 countries. The meta-analysis showed that coronectomy reduced the risk of IAN injury [OR (Odds Ratio): 0.14; 95% CI (confidence intervals): 0.06-0.30; I2 (inconsistency index) = 0%; P = .0001], postoperative pain (OR: 0.97; 95% CI: 0.33-2.86; I2 = 81%; P = .01), and alveolitis (OR: 0.38; 95% CI: 0.13-1.09; I2 = 32.2%; P = .01) when compared to complete tooth extraction. However, it also highlighted a greater risk of reintervention (OR: 5.38; 95% CI: 1.14-25.28; I2 = 0.0%; P = .01). CONCLUSIONS: This study has demonstrated that coronectomy is associated with a decreased risk for IAN injury and decreased pain and localized alveolitis when compared to complete tooth extraction. However, it is essential to acknowledge the higher likelihood of requiring reintervention with coronectomy. Therefore, clinicians should carefully consider the advantages and potential drawbacks of both techniques and tailor their choices to the unique clinical circumstances of each patient.

Bilateral Lingual Nerve Injury Following Endotracheal Intubation: Risk Factors and Diagnostic Considerations.

BACKGROUND Endotracheal intubation is an essential procedure to protect the airway. However, immediate complications like voice hoarseness, cervical spine injury, and tooth trauma are common. One of the rarest complications is lingual nerve palsy. Risk factors include small airway instruments, non-supine position, nitrous oxide use, and difficult intubation. Only 15 cases of lingual nerve injury were identified worldwide, and only 2 of them were bilateral. This case report describes the third case of bilateral lingual nerve palsy after intubation. CASE REPORT We present a 52-year-old woman admitted for a total abdominal hysterectomy. Postoperatively, the patient noted voice hoarseness, left tongue numbness, and loss of taste on both sides of the tongue. MRI brain revealed no new masses or lesions, and a diagnosis of bilateral lingual nerve palsy was made. She was treated conservatively with symptom observation for 14 weeks. On follow-up, she remained with only a patch of numbness and dryness, and loss of taste on the top middle area of the tongue. CONCLUSIONS Lingual nerve palsy is a very rare but devastating adverse effect of airway manipulation. Symptoms can include dryness, loss of sensation, and loss of taste of the anterior two-thirds of the tongue on the ipsilateral side. Salivary function assessment is important to determine the location of peripheral nerve injury. All possible causes like stroke, hemorrhage, and nerve impingement should be evaluated. MRI is advised to exclude central etiologies. Steroids may be used to decrease tissue edema and inflammation.

The assesment of relationship between the angulation of impacted mandibular third molar teeth and the thickness of lingual bone: A prospective clinical study

Background: Our purpose was to investigate the relationship between the angulation of mandibular third molars and the thickness of the lingual bone, which can affect the risk of lingual nerve damage during lower third molars surgical extraction. Material and Methods: This study consisted of 104 patients (42 males and 62 females), aged between 18-42 years (24.67 ± 6.11 years). Cone Beam Computed Tomography (CBCT) images were taken for preoperative assessment. The teeth were divided into four groups according to their positions: mesioangular, distoangular, vertical and horizontal. Lingual bone thickness around impacted teeth were measured at three points: cementoenamel junction (CEJ) of the mandibular second molar, mid-root of the impacted third molar, and apex of the impacted third molar root. Two predisposing factors of lingual nerve damage were recorded: lingual bone perforated by the impacted tooth and lingual bone thinner than 1 mm. Additionally, buccolingual angulations of the teeth in each group were measured. Impacted mandibular third molars were removed in usual way. One week after surgery, the patients were evaluated regarding lingual nerve paresthesia. Results: None of the 104 patients experienced paresthesia, including the ones who had teeth with close proximity with lingual nerve. The mean thickness of bone was 1.21±0.63 mm at CEJ of the second molar; 1.25±1.02 mm at the mid-root; and 1.06±1.31 mm at the apex. Horizontally impacted teeth had thinner lingual bone at mid-root level (p=0.016). Buccolingual angulated teeth were more often associated with perforated lingual bone (p=0.002). Buccolingual and mesial/distal angulation had negative correlation with lingual bone thickness (p<0.05). Conclusions: As the buccolingual and mesiodistal angulations increase, lingual bone thickness decreases. Horizontally impacted teeth seemed to compromise the integrity of the lingual bone more than impacted teeth in other positions. During the surgery, thin or perforated lingual bone may result in displacement of the impacted tooth lingually

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The effect of unilateral lingual nerve injury on the kinematics of mastication in pigs.

OBJECTIVE: This study evaluates the effect of unilateral lingual sensory loss on the spatial and temporal dynamics of jaw movements during pig chewing. DESIGN: X-ray Reconstruction of Moving Morphology (XROMM) was used to reconstruct the 3-dimensional jaw movements of 6 pigs during chewing before and after complete unilateral lingual nerve transection. The effect of the transection were evaluated at the temporal and spatial level using Multiple Analysis of Variance. Temporal variables include gape cycle and phase durations, and the corresponding relative phase durations. Spatial variables include the amplitude of jaw opening, jaw yaw, and mandibular retraction-protraction. RESULTS: The temporal and spatial dynamics of jaw movements did not differ when chewing ipsilateral versus contralateral to the transection. When compared to pre-transection data, 4 of the 6 animals showed significant changes in temporal characteristics of the gape cycle following the transection, irrespective of chewing side, but the specific response to the lesion was highly dependent on the animal. On the other hand, in affected individuals the amplitude of jaw movements was altered similarly in all 3 dimensions: jaw opening and protraction-retraction increased whereas jaw yaw decreased. CONCLUSION: The variable impact of this injury in this animal model suggests that individuals use different compensatory strategies to adjust or maintain the temporal dynamics of the gape cycle. Because the amplitude of jaw movements are more adversely affected than their timing, results suggest that maintaining the tongue-jaw coordination is critical and this can come at the expense of bolus handling and masticatory performance.

Profiling intraoral neuropathic disturbances following lingual nerve injury and in burning mouth syndrome.

BACKGROUND: The aim of the study was to analyse intraoral neurophysiological changes in patients with unilateral lingual nerve lesions as well as patients with Burning Mouth Syndrome (BMS) by applying a standardized Quantitative Sensory Testing (QST) protocol. METHODS: The study included patients suffering from a peripheral lesion of the lingual nerve (n = 4), from BMS (n = 5) and healthy controls (n = 8). Neurophysiological tests were performed in the innervation areas of the tongue bilaterally. For BMS patients the dorsal foot area was used as reference. RESULTS: For patients with peripheral lesion of the lingual nerve the affected side of the tongue showed increased thresholds for thermal (p < 0.05-0.001) and mechanical (p < 0.01-0.001) QST parameters, indicating a hypoesthesia and thermal hypofunction. In BMS patients, a pinprick hypoalgesia (p < 0.001), a cold hyperalgesia (p < 0.01) and cold/warmth hypoesthesia (p < 0.01) could be detected. CONCLUSIONS: The results of this study verified the lingual nerve lesion in our patients as a peripheral dysfunction. The profile showed a loss of sensory function for small and large fibre mediated stimuli. A more differentiated classification of the lingual nerve injury was possible with QST, regarding profile, type and severity of the neurologic lesion. BMS could be seen as neuropathy with variable central and peripheral contributions among individuals resulting in chronic pain.

Prognosis After Surgical Treatment of Trigeminal Neuropathy with a PGA-c Tube: Report of 10 Cases.

OBJECTIVE: Although surgery using a polyglycolic acid-collagen (PGA-c) tube is effective for peripheral nerve injury-induced chronic hand pain, it has not been applied to trigeminal nerve lesions because of the difficult approach. We used a PGA-c tube during surgery for trigeminal neuropathy and evaluated its prognosis based on the outcomes. DESIGN: Case report. SETTING AND PATIENTS: In the dental anesthesia division of a university hospital, 11 patients with severe dysesthesia underwent surgical repair of a damaged lingual nerve (LN) or inferior alveolar nerve (IAN). One patient was lost to follow-up. Changes in quantitative sensory testing (QST) and the presence of dysesthesia as a treatment outcome were compared preoperatively and postoperatively in 10 patients. Two surgical treatments, bridging or encircling peripheral nerves, were applied. Bridging of both stumps was selected when neurotmesis was detected or the nerve was lacerated during surgery (N = 4). Otherwise, a longitudinal PGA-c tube was used to encircle the lesion (N = 6). Outcomes were evaluated 2 months to 8 years postoperatively. RESULTS: Both methods improved the patients' condition based on QST results (brush stroke perception, mechanical touch threshold, sensitivity to cold/hot stimuli). Preoperative allodynia or dysesthesia was resolved in six patients and greatly reduced in four. Two patients (one with inflammation-induced pain, one with implant-related pain) developed prolonged postoperative allodynia requiring pain-relief medication. CONCLUSIONS: Use of a PGA-c tube for surgical treatment of intractable pain due to LN or IAN neuropathy helps alleviate sensory impairment. The possibility of new dysesthesias emerging postoperatively, however, should be noted.