Treatment after inadequate immediate replantation of accidentally extracted immature mandibular premolar during primary molar extraction

During extraction of the primary mandibular right second molar in an 11‐year‐old girl, the unerupted second premolar was accidentally extracted. Clinical and radiographic examination showed that the immediately replanted immature premolar was not oriented and positioned correctly. Four hours later, treatment consisted of manual extrusion of the permanent tooth bud, rotation, and gentle repositioning into its original position. Adequate replantation was confirmed by a post‐operative radiograph. After 2 years and 4 months, clinical examination revealed normal, healthy appearance of the replanted tooth, no sensitivity to percussion, no tenderness to palpation, and a slight response to a cold pulp sensibility test. A radiograph showed completely developed root with closed apical foramen, slightly irregular root morphology and shorter root length, complete obliteration of the pulp, and no signs of periapical pathosis.     

International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 2. Avulsion of permanent teeth

Avulsion of permanent teeth is one of the most serious dental injuries. Prompt and correct emergency management is essential for attaining the best outcome after this injury. The International Association of Dental Traumatology (IADT) has developed these Guidelines as a consensus statement after a comprehensive review of the dental literature and working group discussions. It represents the current best evidence and practice based on that literature search and expert opinions. Experienced researchers and clinicians from various specialties and the general dentistry community were included in the working group. In cases where the published data did not appear conclusive, recommendations were based on consensus opinions or majority decisions of the working group. They were then reviewed and approved by the members of the IADT Board of Directors. The purpose of these Guidelines is to provide clinicians with the most widely accepted and scientifically plausible approaches for the immediate or urgent care of avulsed permanent teeth. The IADT does not, and cannot, guarantee favorable outcomes from adherence to the Guidelines. However, the IADT believes that their application can maximize the probability of favorable outcomes.     

International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: General introduction

Traumatic dental injuries (TDIs) occur most frequently in children and young adults. Older adults also suffer TDIs but at significantly lower rates than individuals in the younger cohorts. Luxation injuries are the most common TDIs in the primary dentition, whereas crown fractures are more commonly reported for the permanent teeth. Proper diagnosis, treatment planning and follow up are very important to assure a favorable outcome. These updates of the International Association of Dental Traumatology's (IADT) Guidelines include a comprehensive review of the current dental literature using EMBASE, MEDLINE, PUBMED, Scopus, and Cochrane Databases for Systematic Reviews searches from 1996 to 2019 and a search of the journal Dental Traumatology from 2000 to 2019. The goal of these guidelines is to provide information for the immediate or urgent care of TDIs. It is understood that some follow‐up treatment may require secondary and tertiary interventions involving dental and medical specialists with experience in dental trauma. As with previous guidelines, the current working group included experienced investigators and clinicians from various dental specialties and general practice. The current revision represents the best evidence based on the available literature and expert opinions. In cases where the published data were not conclusive, recommendations were based on the consensus opinions of the working group. They were then reviewed and approved by the members of the IADT Board of Directors. It is understood that guidelines are to be applied using careful evaluation of the specific clinical circumstances, the clinician's judgment, and the patient's characteristics, including the probability of compliance, finances and a clear understanding of the immediate and long‐term outcomes of the various treatment options vs non‐treatment. The IADT does not, and cannot, guarantee favorable outcomes from adherence to the Guidelines. However, the IADT believes that their application can maximize the probability of favorable outcomes.     

年轻恒牙嵌入性脱位的X线追踪观察分析

目的:通过对年轻恒牙嵌入性脱位的X线片进行回顾性研究,观察患牙复位、牙根发育和牙根吸收情况,并分析其影响因素。方法:收集2013年1月~2019年3月发生嵌入性脱位的年轻恒牙病例,分析其X线片,了解患牙复位、牙根发育及牙根吸收情况。结果:所有患牙基本复位,牙根继续发育占66.7%,发生替代性吸收占25%;嵌入程度较轻的患牙利于牙髓存活(P=0.008);自然再萌的患牙可减少替代性吸收(P=0.005);牙髓存活的患牙牙根可发育,且无替代性吸收(P<0.001)。结论:嵌入性脱位的年轻恒牙牙髓可存活,且牙根可继续发育。牙髓存活的患牙利于牙根发育、减少替代性吸收。重度嵌入的年轻恒牙可有萌出潜力。     

自体牙移植术前难度预判因素的筛选及分析

目的:设计自体牙移植术前难度预判量表,并进行统计学验证。方法:基于文献支持和临床经验总结,对自体牙移植术前难度预判的可能因素进行统计学分析,筛选出相关性较高的11条因素并编制量表,通过96病例进行实际难度判定。采用SPSS 23.0软件包对量表进行信度和效度检验。结果:对96例病例进行难度预判的结果进行统计学分析,量表检测的克隆巴赫系数（信度值）为0.853,皮尔逊相关系数（内容效度值）为0.745,KMO值（结构效度值）为0.704,以上检验均有统计学意义。结论:所设计自体牙移植术前难度预判量表合理可行,适用于初学者进行术前难度预判分析。     

不同咬合接触对单颗后牙种植修复咬合平衡的影响

目的: 研究不同咬合接触方式对咬合平衡指数的影响,为改进种植修复咬合平衡提供依据。方法: 选择2018年12月—2019年12月上海市普陀区眼病牙病防治所行单颗后牙种植修复的患者24例,均采用标准化种植流程,按照修复体与对颌牙将被调整到的咬合接触紧密程度不同,随机分为A、B 2组,分别使用12 μm和20 μm咬合纸进行调整,使咬合纸在修复体和对颌牙咬紧时恰好可以有阻力抽出。应用T-scan咬合力分析仪分别测定修复前及修复当天、3个月、6个月、12个月和18个月牙尖交错位时咬合力分布情况,换算成咬合平衡指数。采用SPSS 21.0软件包对数据进行统计学分析。结果: 2组在修复前咬合平衡指数分别为（-0.389+0.066）和（-0.368+0.055）,修复当天分别为（-0.249+0.069）和（-0.283+0.056）,差异无统计学意义（P>0.05）;修复3个月时分别为（-0.052+0.022）和（-0.169+0.063）,6个月时分别为（-0.025+0.015）和（-0.088+0.045）,12个月时分别为（-0.010+0.008）和（-0.029+0.016）,18个月时分别为（-0.000+0.000）和（-0.006+0.008）,2组咬合平衡指数均呈逐渐增加至0的趋势,A组绝对值远小于B组,但A组的上升幅度远大于B组,差异有统计学意义（P<0.05）。结论: 单颗后牙种植修复能逐渐恢复咬合平衡,选用12 μm咬合纸调整修复体与对颌牙咬合接触紧密程度,能更早获得咬合平衡。     

非综合征型先天缺牙致病基因和分子机制的研究进展

先天缺牙是牙齿发育过程中常见的牙数目发育异常,对患者的颌面部发育及美观和咀嚼功能产生严重的影响。根据有无伴发全身症状,先天缺牙可分为综合征型先天缺牙与非综合征型先天缺牙。近几年发现新的相关基因和新的突变位点及分子机制已成为目前非综合征型先天缺牙基因研究的主要方向。本文通过对近年来文献的回顾,对与非综合征型先天缺牙主要相关的Wnt/β-catenin信号通路、TGF-β/BMP信号通路、PAX9基因和MSX1基因、EDA/EDAR/NF-κb信号通路的分子机制以及相互调节的紧密联系进行综述,为未来先天缺牙的防治提供了新的理论基础。非综合征型先天缺牙致病基因的分子机制的研究目前甚少,对于其机制的精准探索将成为先天缺牙未来主要的研究方向之一。     

骨皮质切开术辅助正畸治疗的研究进展

近年来,寻求正畸治疗的成年患者数量日益增多,如何加速正畸牙齿移动、缩短正畸疗程,并同时降低与正畸治疗时间较长相关的牙体、牙周疾病风险成为医生和患者共同关注的焦点。目前已报道的加速牙齿移动的方法中,经基础和临床研究证实,骨皮质切开术可有效加速正畸牙移动、缩短疗程并减少与正畸时间相关的牙体、牙周疾病,且其术式也随着临床操作、手术设备、计算机技术的更新和进步而变得更加微创、简便、精确、有效。文章就骨皮质切开术辅助正畸治疗的历史起源与发展、加速正畸牙齿移动的原理、术式变化、适应证与禁忌证、临床应用等方面做一综述。     

Enamel and dentin mineralization in familial hypophosphatemic rickets: a micro-CT study

Objectives:

The aim of the present study was to analyse the mineralization pattern of enamel and dentin in patients affected by X-linked hypophosphatemic rickets (XLHR) using micro-CT (µCT), and to associate enamel and dentin mineralization in primary and permanent teeth with tooth position, gender and the presence/absence of this disease.

Methods:

19 teeth were collected from 5 individuals from the same family, 1 non-affected by XLHR and 4 affected by XLHR. Gender, age, tooth position (anterior/posterior) and tooth type (deciduous/permanent) were recorded for each patient. Following collection, teeth were placed in 0.1% thymol solution until µCT scan. Projection images were reconstructed and analysed. A plot profile describing the greyscale distance relationship in µCT images was achieved through a line bisecting each tooth in a region with the presence of enamel and dentin. The enamel and dentin mineralization densities were measured and compared. Univariate ANOVA and post hoc Tukey tests were used for all comparisons.

Results:

Teeth of all affected patients presented dentin with a different mineralization pattern compared with the teeth of healthy patients with dentin defects observed next to the pulp chambers. Highly significant differences were found for gray values between anterior and posterior teeth (p < 0.05), affected and non-affected (p < 0.05), as well as when position and disease status were considered (p < 0.05).

Conclusions:

In conclusion, the mineralization patterns of dentin differed when comparing teeth from patients with and without FHR, mainly next to pulp chambers where areas with porosity and consequently lower mineral density and dentin defects were found.