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.

Expression of c-fos, OPG, OPGL in rabbit mandibular distraction osteogenesis zone / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the possible signal transduction mechanism of the mechanical stress induced by the distraction procedure in osteocytes.</p><p><b>METHODS</b>An animal model of mandibular distraction osteogenesis in rabbits was established. The expressions of c-fos, OPG and OPGL were detected by ultrasensitive S-P immunohistochemical method.</p><p><b>RESULT</b>At 4 and 8 days after distraction, distraction zone showed strong positive staining of c-fos, which were apparently higher than that in distraction zone of 2, 4 and 6 weeks after consolidation. At 4 and 8 days after distraction and 2 weeks after consolidation, the expression of OPG was strong, and then wore off gradually at 4 and 6 weeks after consolidation. Weak signals of OPGL could be detected at 6 weeks after consolidation only.</p><p><b>CONCLUSION</b>c-fos, OPG and OPGL are important regulators in distraction osteogenesis. c-fos is interrelated with the mechanical stress induced by the distraction procedure closely, OPG promotes new bone formation, while OPGL plays a more active role in bone remodeling.</p>

The relationship between lymphangiogenesis and cervical lymph node micrometastasis in oral squamous cell carcinoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To probe the relationship between lymphangiogenesis and cervical lymph node micrometastasis in oral squamous cell carcinoma.</p><p><b>METHODS</b>The microlymphatic vessel density was detected with enzyme histo-chemical method in 47 cases of oral squamous cell carcinoma and 10 cases of normal oral mucosa; 355 lymphnodes were detected with immunohistochemically using monoantibody AE3.</p><p><b>RESULTS</b>The mean MLVD was 14.04 +/- 6.92 in tumor group, or 5.48 +/- 2.62 in normal group. The difference was (P < 0.001). The percentage of tumor with expression CK was 48.9%. The mean MLVD was 16.94 +/- 5.43 in CK positive group, or 11.26 +/- 5.00 in CK negative group, There was difference significant (P < 0.001).</p><p><b>CONCLUSIONS</b>Lymphangiogenesis plays a key role in cervical lymph node micrometastasis of oral squamous cell carcinoma.</p>

Expression related to vascular endothelial growth factor C and induced nitride oxide synthesizase in lymph node micrometastasis of oral squamous cell carcinoma / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the relationship of vascular endothelial growth factor C (VEGF-C) and induced nitride oxide synthesizase (iNOS) expression in lymph node micrometastasis of oral squamous cell carcinoma.</p><p><b>METHODS</b>Samples were obtained from 47 cases of oral squamous cell carcinoma and 15 cases with normal oral mucosa, VEGF-C and iNOS mRNA expression were detected by RT-PCR method. Lymph node micrometastasis of 10 normal lymph nodes and 355 lymph nodes from 47 cases of oral squamous cell carcinoma was detected with immunohistochemical reaction in cytokeratin antibody.</p><p><b>RESULTS</b>The percentages in tumors with higher expression were 57.4% for VEGF-C, 68.1% for iNOS (P < 0.05). They were significantly higher than that of normal groups. Significant positive relationship was found between VEGF-C and iNOS (P < 0.01). The positive rate of cytokeratin (CK) was 48.9%. Significant positive relationship was found between VEGF-C and CK, iNOS and CK (P < 0.01). The expression rates of CK in positive group of VEGF-C and iNOS were 63.0%, 65.6% respectively, and were significant higher than negative groups.</p><p><b>CONCLUSION</b>Expression of VEGF-C and iNOS in lymph node micrometastasis of oral squamous cell carcinoma is significant related.</p>