U-Net神经网络分割锥形束CT影像中下颌磨牙牙体与牙髓腔及其准确性验证

目的: 使用U-net卷积神经网络实现锥形束CT（cone-beam CT, CBCT）影像中下颌磨牙的牙体和牙髓腔的自动分割,采用基于显微CT（Micro-CT）扫描结果构建的三维模型作为金标准,评估分割准确性。方法: 从同济大学附属口腔医院放射科收集20组包含完整单侧下颌磨牙的口腔小视野CBCT数据,预处理后,由牙体牙髓病学专家使用MITK Workbench软件手动标注牙体与牙髓腔,作为U-net神经网络分割算法的训练集。另收集5颗下颌磨牙和相应的小视野CBCT数据,5组数据经相同预处理后作为测试集。随后由完成训练的神经网络和同一专家对测试集数据进行牙体和牙髓腔分割和三维重建。离体牙预处理后行Micro-CT扫描,将三维重建后获得的模型作为金标准。分别比较测试集数据中,专家的手动标注、神经网络分割结果与金标准两两之间的差异。采用Dice相似性系数（Dice similarity coefficient, DSC）、平均对称表面距离（average symmetric surface distance, ASSD）、Hausdorff距离（Hausdorff distance, HD）和形态差异分析对结果进行评估。采用SPSS 20.0软件包对数据进行统计学分析。结果: 神经网络分割结果与金标准相比,其牙体组的DSC为(95.30±1.01)%、ASSD为(0.11±0.02) mm、HD为(1.05±0.31) mm,牙髓腔组的DSC为(81.21±2.27)%、ASSD为(0.15±0.05) mm、HD为(3.29±1.85) mm,结合形态差异分析结果显示,神经网络的分割结果与金标准的牙体与髓室部分基本相似,但在根管部分,能分割出较粗的根管,对于根管下段和侧支根管等较细的根管分割能力有限。结论: 在现有实验条件下,以专家手动标注作为训练样本的U-net神经网络,实现了在CBCT影像上对下颌磨牙牙体与髓室的自动化精准分割。但对根管部分,其分割结果有待进一步提升。     

Bone regeneration in critical-sized mandibular symphysis defects using bioceramics with or without bone marrow mesenchymal stem cells in healthy,diabetic, osteoporotic,and diabetic-osteoporotic rats

ObjectivesTo compare new bone formation in mandibular critical-sized bone defects (CSBDs) in healthy, diabetic, osteoporotic, and diabetic-osteoporotic rats filled with bioceramics (BCs) with or without bone marrow mesenchymal stem cells (BMSCs).MethodsA total of 64 adult female Sprague-Dawley rats were randomized into four groups (n = 16 per group): Group 1 healthy, Group 2 diabetic, Group 3 osteoporotic, and Group 4 diabetic-osteoporotic rats. Streptozotocin was used to induce type 1 diabetes in Group 2 and 4, while bilateral ovariectomy was used to induce osteoporosis in Group 3 and 4. The central portion of the rat mandibular symphysis was used as a physiological CSBD. In each group, eight defects were filled with BC (hydroxypatatite 60% and β-tricalcium phosphate 40%) alone and eight with BMSCs cultured on BC. The animals were sacrificed at 4 and 8 weeks, and the mandibles were processed for micro-computed tomography to analyze radiological union and bone mineral density (BMD); histological analysis of the bone union; and immunohistochemical analysis, which included immunoreactivity of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2).ResultsIn all groups (healthy, diabetics, osteoporotics, and diabetics-osteoporotics), the CSBDs filled with BC + BMSCs showed greater radiological bone union, BMD, histological bone union, and more VEGF and BMP-2 positivity, in comparison with CSBDs treated with BC alone (at 4 and 8 weeks).ConclusionsApplication of BMSCs cultured on BCs improves bone regeneration in CSBDs compared with application of BCs alone in healthy, diabetic, osteoporotic, and diabetic-osteoporotic rats.     

Clinical course of masticatory function recovery following arthrocentesis in patients with unilateral mandibular condyle head fracture

The aim of this study was to investigate the clinical course of masticatory function recovery following arthrocentesis. Patients with a unilateral condylar head fracture who underwent arthrocentesis for therapeutic reasons were evaluated and compared with patients with a unilateral condylar head fracture who did not undergo arthrocentesis. At 3 months after treatment, the occlusal contact area and maximum bite force in patients with a fracture treated with arthrocentesis were greater than in those who did not receive arthrocentesis at the same time points, although the differences were not significant. Moreover, at 1 and 3 months following arthrocentesis, mean (±SD) occlusal contact area (1 month: 1.99 ± 0.55 mm², p = 0.01; 3 months: 2.90 ± 1.36 mm², p = 0.03) and maximum bite force (1 month: 82.45 ± 15.04 N, p = 0.01; 3 months: 101.11 ± 14.53 N, p = 0.01) on the fractured side in patients who underwent that treatment were significantly reduced when compared with those on the non-fractured side. The authors conclude that if the priority is to avoid open reduction and internal fixation, then the arthrocentesis approach might be a less invasive alternative, albeit with the price of a prolonged healing interval.     

The mid-mesial canal prevalence in mandibular molars of a Saudi population: A cone-beam computed tomography study

IntroductionThe aim was to assess the prevalence of Mid Mesial Canal (MMC) in the first and second mandibular molars in a Saudi subpopulation sample and assess its relation to side, gender, and age using Cone beam computed tomography (CBCT).MethodsThe CBCT scans at King Saud University Dental Hospital between 2016 and 2019 were reviewed and filtered. The MMC of the mandibular molars were assessed according to Pomeranz et al. classification which was: (1) independent; (2) fin; (3) confluent with the mesiobuccal canal; and (4) confluent with the mesiolingual canal. Three calibrated observers examined the MMC on all planes at both sides. Age and gender factors were used to analyze that prevalence. A chi-squared test was used and (P ≤ 0.05) was considered to be statistically significant.Results395 patients, and 1377 teeth met the inclusion criteria. The total number of mid-mesial canals was 12 (0.9%): nine at the mandibular first molar (1.3%) and three in the mandibular second molar (0.4%). The most common type of mid-mesial canal was confluent (n = 10), of which 6 fused with the mesiobuccal canal and 4 fused with the mesiolingual canal. Two canals were of the fin type, and there was no instance of independent mid-mesial canal. There was no significant difference between all variables: tooth type, tooth side, patient gender, and patient age group (p > 0.05).ConclusionIn this study, the most common MMC configuration was the confluent type followed by the fin type and no independent type were found. The patient side, gender and age did not influence the prevalence of the MMC.     

会阴Ⅲ～Ⅳ度裂伤及特殊裂伤的预防和处理

会阴Ⅲ～Ⅳ度裂伤是阴道分娩的严重并发症，由于裂伤累及肛门括约肌复合体和（或）肛门黏膜，又称为产科相关肛门括约肌损伤（OASIS），是导致产后肛门失禁最常见的原因，严重影响生活质量。阴道分娩后准确评估会阴裂伤程度并及时修复解剖结构对恢复肛门括约肌功能、改善预后至关重要；但临床实践中隐匿性OASIS有时被漏诊，不能及时识别、修复或愈合不良等，可导致会阴-直肠瘘或直肠-阴道瘘。需要加强预防和管理会阴Ⅲ～Ⅳ度裂伤，恰当运用质量管理工具，分析导致OASIS的风险因素和关键环节，从妊娠期和产程管理、助产能力提升、风险评估、预防和治疗等关键环节着手，减少或避免OASIS发生，提升识别和修复OASIS的能力。     

地塞米松不同给药途径对下颌阻生第三磨牙拔除术后的疗效观察

目的:评价地塞米松不同给药途径(冠周局部注射和口服)在预防下颌阻生第三磨牙拔除术后肿胀、疼痛及张口受限中的疗效。方法:对480例患者的下颌阻生第三磨牙根据阻生类型进行分组(高位、中位、低位),每组中再分为实验组(拔牙术后局部注射地塞米松)和对照组(拔牙术后口服地塞米松),对患者术后第1、3、7天进行随访分析,对患者肿胀指数、疼痛程度和张口受限程度进行统计分析。结果:在拔牙术后第1天和第7天,高位组、中位组和低位组中的实验组与对照组在肿胀指数、疼痛程度和张口受限程度方面比较差异无统计学意义(P>0.05);术后第3天,高位组和中位组中的实验组与对照组在肿胀指数、疼痛程度和张口受限程度差异无统计学意义(P>0.05),低位组中的实验组与对照组相比,在肿胀反应中具有更好的预防效果(P<0.05),在疼痛程度和张口受限程度中具有一定的缓解效果(P>0.05)。结论:下颌阻生第三磨牙拔除术后,冠周局部给予地塞米松能够防治和减轻术后肿胀、疼痛以及张口受限的发生。     

妊娠晚期危重型新型冠状病毒肺炎一例

本文报告一例妊娠晚期合并新型冠状病毒肺炎(COVID-19)危重型孕妇。患者32岁,孕35周+2因"咽痛4 d,发热3 h"入院。入院前曾至湖北孝感应城,回家隔离期间发病。入院后病情进展迅速,7 h后出现左侧胸背部疼痛、气促、头晕,迅即出现呼吸衰竭、感染性休克。考虑病情严重,且有2次剖宫产史,行紧急子宫下段剖宫产术。术前血气分析示呼吸衰竭、呼吸性酸中毒合并代谢性酸中毒。术中娩出一男婴,2700 g,1 min Apgar评分1分(心率20次/min),经复苏抢救,5和10 min评分均为1分,家属放弃抢救后死亡。产妇术后气管插管呼吸机维持,同时给予其他支持治疗。入院时的新型冠状病毒核酸检测结果于分娩后报告为阳性,遂转入定点医院治疗。患者术后26 d体外膜肺氧合脱机成功,术后36 d脱离呼吸机,进入康复阶段。     

下颌磨牙区即拔即种的临床疗效观察

目的 探究下颌磨牙区即拔即种的临床疗效。方法 选取2017年1月至2019年1月江门市口腔医院收治的60例需进行下颌磨牙区种植的患者随机分为A、B组,A组给予即拔即种,B组给予延期种植,比较两组留存率、浅蝶形骨吸收率、种植12个月后PIS指标及满意度进行评价。结果 随访12个月两组留存率均为100%,浅碟形骨吸收率A组前磨牙为16.67%、磨牙为22.22%,B组前磨牙为10.00%、磨牙为25.00%,差异均无统计学意义(P＞0.05),A组植入30个种植体,60个牙间乳头,其中3度29个、2度24个、1度7个,B组植入30个种植体,60个牙间乳头,其中3度14个、2度24个、1度22个,A组牙间乳头PIS指标优于B组,且A组牙间乳头PIS评分(2.36±0.52)较B组(1.87±0.48)显著提高,差异均具有统计学意义(P＜0.05),A组对治疗效果满意率为93.33%较B组66.67%显著提高,差异具有统计学意义(P＜0.05)。结论 对于下颌磨牙区缺牙患者可采取即拔即种的方法修复,缩短缺牙时间,促进咬合和咀嚼功能恢复,舒适且美观,提高患者的满意度,值得在临床上推广。