OBJECTIVE:The primary focus of this investigation was to evaluate the biomechanical effects of high trimline design aligners on the distalization of mandibular molars, employing three-dimensional finite element analysis (3D-FEA). The study concentrated on aspects such as tooth movement, stress distribution, and anchorage control. METHODS:Utilizing Cone-beam computed tomography (CBCT) data, a detailed 3D geometrical model was constructed for finite element analysis. This model was used to assess four variations of aligner trimlines, alongside the employment of Class III traction. Analyses were conducted to examine stress distributions and tooth displacements in these different scenarios. RESULTS:Aligners with a high trimline design were found to be more effective in facilitating the distal movement of mandibular molars than those with scalloped trimlines, providing improved management over tooth movement and stress distribution. In specific configurations where Class III traction was applied, a reduction in the deformation of anterior teeth was observed, which enhanced anchorage stability. Nevertheless, the anterior teeth in all configurations were subjected to compressive stresses that surpassed thresholds likely to induce external root resorption, underlining the importance of vigilant monitoring. CONCLUSIONS:The research verified the biomechanical advantages of high trimline aligners in the distal movement of mandibular molars and underscored the critical role of aligner design and traction application in optimizing orthodontic treatment outcomes. Additionally, it raised concerns regarding the potential for root resorption due to significant stress in the periodontal ligament, necessitating thorough observation of patients, particularly those fitted with high trimline aligners. Despite these insights, the study's findings are derived from the data of a single patient, suggesting a need for further investigations involving broader samples and extended clinical assessments.

This case report describes a 21-year-old orthodontic patient experienced the external apical root resorption of maxillary central incisors with pulpitis during the orthodontic movement. The active cooperation of orthodontists and endodontists demonstrated the satisfactory treatment outcome and prevented further apical root resorption. The etiology of external apical root resorption is comprehensive, orthodontists should be armed with an adequate training and scientific knowledge, and keep the treatment mechanism simple and precise to guard against it. Besides, we should know the right timing of endodontic treatment and applying orthodontic force when external apical root resorption occurs.

目的 在当前医药卫生体制改革背景下,分析我院医疗运行及医改相关工作数据,总结经验,提出应对措施,以期为口腔专科医院能够借助医药卫生体制改革契机实现自身发展提供借鉴.方法 采取自身同期对照法和问卷调查法,对比我院医药分开综合改革前一年(2016年)及改革实施当年(2017年)不同时段内的运行数据,评价相关工作的实施效果,分析在当前医改背景下对我院发展所面临的问题,并提出相应对策.结果 医药分开综合改革政策在我院实施后,医疗服务量呈现增幅趋势,疑难复杂病例占比有降低.此外,我院通过有序开展对外医疗合作工作,有效提高了医联体单位专业技术诊治水平.结论 在深化医药卫生体制改革过程中,口腔专科医院应不断强化内部管理,以患者为中心,改善和提升医疗服务质量,落实精细化管理;发挥专科医疗联合体的作用,提升区域口腔医疗机构的诊疗水平,形成资源共享,为逐步推进分级诊疗工作打下基础.

目的 通过组织学方法 探讨上颌半快速扩弓(semirapid maxillary expansion,SRME)与上颌慢速扩弓(slow maxillary expansion,SME)对小型猪上颌磨牙颊侧骨板骨重建的影响.方法 10月龄雄性巴马小型猪11只,随机分为三组:SRME组4只,SME组4只,对照组3只.实验组采用铸造连冠式螺旋扩弓器加力结束保持2个月后取标本.对照组只粘固铸造金属连冠,不加力.对标本进行组织学研究.结果 SRME组、SME组上颌磨牙颊侧牙槽骨板中骨吸收陷窝数量、面积及破骨细胞数量均明显大于对照组(P<0.05);SRME组与SME组骨吸收陷窝数量、面积及破骨细胞数量间无明显差异(P>0.05).结论 SRME与SME扩弓保持2个月的颊侧牙槽骨板破坏程度无明显差异;上颌扩弓保持2个月后上颌磨牙颊侧牙槽骨板仍存在以骨吸收为主的骨重建活动,有复发可能.为达到长期稳定性,需延长保持时间.

The rapid development of digital technology has made the processes of orthodontic data collection, diag⁃ nosis, design and treatment more accurate, comprehensive, convenient and safe and has improved the clinical efficiency of orthodontists. Safe, non⁃invasive, rapid three⁃dimensional facial imaging and digital dental models have enabled ortho⁃ dontists to collect accurately visualized case data. In addition, during diagnosis and design, orthodontists can compre⁃ hensively analyze teeth, jaws, and cranial surfaces in 3 dimensions. Through advances that range from digitized whole⁃ dentition information to computer⁃replicated design and computer⁃aided manufacturing, invisible orthodontic technology without brackets has become one of the best manifestations of the combination of digital technology and oral orthodon⁃ tics. In addition, individualized fixed orthodontic devices have become widely used in orthodontic clinics. In this paper,the applications of digital technology in orthodontic clinics is described. It is hoped that orthodontists will be able to use digital technology rationally to benefit increasing numbers of patients with orthodontic demands.

目的 了解北京市口腔医疗机构的清洗消毒灭菌现况,提出改进措施,为规范管理提供基础数据.方法 采用现场调查与生物监测的方法,对北京市口腔医疗机构的消毒与灭菌管理现状进行调查.结果 共调查不同级别口腔医疗机构257家,有71.21％的医疗机构在口腔科进行医疗器械清洗消毒与灭菌,有88.72％的口腔医疗机构制定了消毒相关制度,有91.87％的消毒室人员进行了岗前培训.现场监测显示,超声清洗效果总体合格率为69.00％,小型压力蒸汽灭菌器灭菌温度总体合格率为84.90％,灭菌时间总体合格率为64.08％,生物监测总体合格率为99.18％.结论 北京市口腔医疗机构在口腔科进行器械清洗消毒与灭菌的比例较高,仍存在安全风险,应加强监督管理.

Objective To explore the changes of maxillary buccal bone before RME,after RME and post retention using CBCT 3-dimensional imaging.Methods Eight male Bama mini-pigs at 10 months of age were randomly divided into two groups:Five pigs were in the experimental group and 3 in the control group.Before RME (T1),after RME (T2),3 months after retention (T3),all pigs were scanned using CBCT to analyze the thickness and height changes of buccal bone (BBT,△BMBL).Results BMBL,BBT representing the maxillary buccal alveolar bone height and thickness had significant changes at T2 compared with control group (P ＜ 0.05).BMBL and BBT had no significant change between T3 and T2 (P＞0.05).Significant corrlation was found between △BMBL and △BBT (γ=-0.96,P＜0.01),between BBT at T1 and △MBBT (γ=-0.90,P＜0.05),between BBT at T1 and △BMBL (γ=-0.84,P＜0.05).Conclusions Alveolar bone height and thickness decreased significantly after RME and the buccal alveolar bone thickness before RME had negative correlation with the possibility of alveolar bone absorption.