Evaluating the risk factors of inferior alveolar nerve injury following removal of the mandibular third molars / 中华口腔医学杂志

Objective: To evaluate the risk factors of inferior alveolar nerve injury (IANI) after surgical removal of the mandibular third molars (M3) and present a new risk scoring system to predict the probability of IANI. Methods: Patients who underwent extraction of M3 in the Stomatology Hospital, Zhejiang University School of Medicine from April 2017 to December 2019 were involved. The investigators enrolled a sample composed of 949 mandibular third molars. Prediction model was used for univariate and multivariate analysis of gender, age, M3, inferior alveolar canal (IAC), and the contact between M3 and IAC, to assess the risk factors of IANI. Combined with the risk factors determined by the outcomes of prediction model, the risk scoring system was constructed. The diagnostic performance of each cut-off score was examined to conduct a risk stratification of IANI risk scores. The predictive ability and reliability of the model were evaluated. Results: In prediction model, twenty nine cases (4.4%, 29/664) experienced postoperative IANI. Number of root (P<0.01), depth of impaction (P<0.05), contact between M3 and IAC (P<0.01) and their contact position (P<0.05) were statistically significant as contributing risk factors of IANI. Specifically, the incidence of temporary IANI was higher in those who aged under 25 years (P<0.001), while female suffer more permanent injury (P<0.05). Based on the IANI risk scoring system, patients were stratified into low-risk, middle-risk and high-risk groups at cutoff scores of 3 and 4. The area under the receiver operator characteristic curve of the risk scoring system were 0.81 [95%CI (0.70-0.90), P=0.002] and 0.80 [95%CI (0.68-0.92), P=0.007] towards good discrimination. Conclusions: Age, gender, number of root, depth of impaction, and contact between M3 and IAC were risk factors of IANI. IANI risk scoring system might help in preoperative assessment, recognition of high-risk cases and decision-making to reduce IANI.

Complicaciones en cirugía ortognática: conceptos actuales y revisión de la literatura / Complications in orthognathic surgery: current concepts and review of the literature

La cirugía ortognática es el tratamiento de elección para corregir deformidades dentofaciales congénitas o adquiridas en menor cantidad de casos, estas técnicas pueden ser aplicadas en la resección de tumores y apnea del sueño. Usualmente se lleva a cabo entre la segunda y tercera década de vida. Dentro de los benefi cios que se obtienen se incluyen una mejor función masticatoria, resultados estables en discrepancias dentofaciales severas y un mejor aspecto estético facial. Sin embargo, aun el cirujano más experimentado puede enfrentar complicaciones, entre las que destacan las vasculares, técnicas, nerviosas, periodontales, infecciosas, oftálmicas, de oclusión, psicológicas y necrosis ósea. Algu-nas de estas complicaciones pueden discutirse en detalle con el paciente antes del procedimiento. A pesar de lo anterior, el tratamiento de cirugía ortognática puede ser considerado como un procedimiento seguro. Las complicaciones se pueden dividir en preoperatorias, transoperatorias y postoperatorias, teniendo en las dos últimas una mayor incidencia.

Orthognathic surgery is the treatment of choice for the correction of congenital or acquired dentofacial deformities; in a minority of cases, the techniques involved can be applied to tumor resection and to treat sleep apnea. This type of surgery is usually performed between the second and third decades of life. The benefi ts obtained include a better chewing function, stable results in severe dentofacial anomalies, and improved facial aesthetics. However, even the most experienced surgeon can encounter a range of issues, most notably vascular, technical, ner-vous, periodontal, infectious, ophthalmic, psychological, those related to occlusion, and bone necrosis. Some of these can be discussed in detail with the patient prior to the procedure. Nevertheless, orthognathic surgery treatment can be considered a safe procedure. Complications can be classifi ed into three types: preoperative, intraoperative, and postoperative, the latter two being the most common.

Correlation between radiographic signs of third molar proximity with inferior alveolar nerve and postoperative occurrence of neurosensory disorders: A prospective, double-blind study

PURPOSE: To evaluate the interference of radiographic factors in the appearance of sensory deficit related to inferior alveolar nerve (IAN) after third molars (3Ms) removal. METHODS: A prospective, double-blind, observational, unicentric study was performed with 126 patients submitted to a surgical procedure of lower 3Ms removal in the period from March to October/2011. Collected data included gender, age, eruption stage of 3Ms, position/angle of 3Ms (Pell-Gregory and Winter classifications, respectively), presence/absence of radiographic signs of 3Ms proximity with the inferior alveolar canal and surgical technique. Occurrence evaluation of the IAN injury was performed on the seventh postoperative day through pin-prick, two-point discrimination and brush directional stroke tests. RESULTS: Predominant radiographic signs were: narrowing of the inferior alveolar canal (68.25%), darkening of root (46.82%) and diversion of the canal (31%). None of the patients presented sensory loss. Sixty-one (48.41%) of the cases had at least one or two radiographic signs of proximity with NAI. Forty-seven (37.3%) had 3 or more signs, and 18 (14.29%) did not have any radiographic signs of proximity to mandibular canal. CONCLUSION: There was not a positive correlation between presence of radiographic signs of 3Ms with IAN proximity and postoperative neurosensory disorders occurrence.

Displacement of endodontic instruments in inferior alveolar canal.

Endodontic instrument breakage is a common occurrence during root canal treatment but the displacement of the separated instrument into the inferior alveolar canal is rare and has never been reported. We hereby present an unusual case of displacement of a separated instrument in the inferior alveolar canal and its retrieval by a simple technique.