氟化物涂膜预防农村地区儿童未建 第一恒磨牙龋

目的探讨氟化物涂膜在预防农村地区儿童未建 第一恒磨牙龋病中的临床效果。 方法运用简单随机抽样方法选取广州市花都区农村地区6~7岁一年级儿童476人,共1462颗未建 第一恒磨牙纳入研究。试验组(n=212,697颗磨牙)两年内每半年予1次牙面涂布氟化物涂膜(多乐氟?),共计5次。对照组(n=264,765颗磨牙)牙面不做涂氟处理。试验开始后每半年复查两组儿童的龋病发病情况。 结果6个月后两组儿童第一恒磨牙龋病发病率、龋面均之间差异无统计学意义(P_发病率=1.000;t_龋面均=0.005,P_龋面均=0.996)。12个月后两组儿童第一恒磨牙龋病发病率、龋面均之间差异无统计学意义(χ²_发病率=1.489,P_发病率=0.222;t_龋面均=1.417,P_龋面均=0.157)。24个月后两组儿童第一恒磨牙龋病发病率、龋面均之间的差异扩大且差异均具有统计学意义(χ²_发病率=11.645,P_发病率=0.001;t_龋面均=3.408,P_龋面均=0.001)。 结论氟化物涂膜能够有效预防农村地区儿童未建 第一恒磨牙龋的发生,值得临床推广应用。     

架在全口义齿修复教学中的应用

架是口腔解剖学和 学的标志性仪器,在口腔科学特别是修复学中应用广泛。在口腔临床诊疗前的操作性教学中, 架应用是必须掌握的技能之一。其中,无牙颌患者的全口义齿修复教学由于涉及重建牙列及咬合,在临床与义齿制作过程中对 架的依赖性更强,有更好的教学意义。     

下颌球帽覆盖义齿与全口义齿戴用2~3年咬合特征研究

目的研究下颌球帽附着体固位覆盖义齿（COD）及全口义齿（CD）修复后2~3年咬合接触特征及差异。 方法采用T-ScanⅡ咬合分析仪对戴用2~3年CD及COD修复患者（各12例）进行体内咬合分布特征及 力升高时间的测定。记录患者义齿左右侧咬合面积不对称指数、咬合力中心（X,Y）值、咬合力前后向分布比率及 力升高时间。 结果（1）CD组、COD组左右侧咬合面积不对称指数、咬合力中心X值,差异无统计学意义（P > 0.05）;（2）COD组咬合中心前移,差异有统计学意义（P < 0.05）;（3） 力升高时间CD组0.28 s,COD组延长为0.59 s,差异有统计学意义（P < 0.05）。 结论正中咬合时,CD戴用2~3年咬合分布、 力升高时间近似正常 ,COD咬合中心向基牙区偏移, 力升高时间延长。     

改良舌弓治疗下颌第一磨牙异位萌出的临床应用

目的探讨改良舌弓治疗下颌第一恒磨牙异位萌出的临床效果。 方法选择于2018年1月至2021年6月于东莞健力口腔医院正畸科就诊的15例下颌第一恒磨牙异位萌出的患儿，年龄7 ~ 8岁，其中5例双侧、10例单侧，以第二乳磨牙作为直接支抗，通过传统的下颌舌弓焊接远端牵引钩，在异位萌出的恒磨牙面粘接舌侧扣联合链状橡皮圈牵引异位萌出恒磨牙向远中，以达到其正常的生理位置。使用SPSS 20.0统计软件分别对治疗前后作为直接支抗牙的第二乳磨牙与异位的第一恒磨牙的倾斜角度与冠近远中高度进行统计学分析，采用配对t检验进行对比，以P<0.05为差异有统计学意义。 结果第二乳磨牙治疗前的倾斜角度为64°±3°，治疗后为63° ± 4°，差异无统计学意义（t = 1.399，P = 0.178）。同样，第二乳磨牙治疗前的近远中冠高比（85% ± 4%）与治疗后（84% ± 4%）相比，差异无统计学意义（t = 0.608，P = 0.550）。异位的下颌第一恒磨牙治疗前的倾斜角度为52° ± 6°，治疗后为69° ± 4°，差异有统计学意义（t = -10.423，P<0.001）。异位的下颌第一恒磨牙治疗后的近远中冠高比（90% ± 3%）高于治疗前（80% ± 5%），差异有统计学意义（t = -8.231，P<0.001）。 结论改良舌弓临床操作简便，提供的支抗良好、充分，能有效治疗下颌第一恒磨牙异位萌出。     

上颌前牵引中两种口内固位装置的临床对比研究

目的探讨快速扩弓与包绕 垫式口内固位装置结合上颌前牵引矫治的效果差异,为临床治疗提供理论依据和参考。 方法选择23例骨性Ⅲ类上颌后缩患者,分为快速扩弓结合上颌前牵引组（13例）和包绕 垫结合上颌前牵引（10例）。对两组患者治疗前及前牵引后的头颅定位侧位片进行头影测量分析,并进行配对t检验;对两组患者治疗前、前牵引后的差值变化进行组间独立样本t检验。 结果两组患者矫治后均出现SNA增大、ANB减小、下颌骨长度增加、Y-axis、MP/FH、MP/SN、PP/MP、U1-SN增大、前下面高、前面高、后面高增加。这些指标的变化差异有统计学意义。快速扩弓组患者前颅底长、上颌骨长度（Ptm-A）明显增加,下切牙明显舌倾。包绕 垫组患者后颅底长明显增加,面角明显减小,前面高明显增加。两组间对比：S-Ba、NPg-FH变化两组差异有统计学意义（P < 0.05）,其余测量值变化差异无统计学意义（P > 0.05）。 结论使用快速扩弓与包绕 垫加上颌前牵引矫治骨性Ⅲ类上颌后缩患者在临床上是确实可行的,可取得满意的疗效。     

无托槽隐形矫治技术治疗高角型开 畸形

目的探讨无托槽隐形矫治技术治疗高角型开 畸形的临床应用并评估其疗效。 方法选取高角型开 畸形患者30例,其中男12例、女18例,年龄18 ~ 30岁,平均24.5岁,应用无托槽隐形矫治技术进行正畸治疗,均采取拔牙矫治,治疗前后拍摄头颅侧位片,测量头影测量指标并使用SPSS 17.0统计学软件进行统计学分析。 结果30例患者矫治后前牙覆 恢复正常,面型得到明显改善。SNA角减小1.6°（P<0.001）,SNB角减小0.5°（P = 0.038）,ANB角减小1.1°（P<0.001）,GoGn-SN角减小1.7°（P<0.001）,U1-NA减小3.7 mm（P<0.001）,L1-NB减小1.8 mm（P = 0.001）,U1-L1角增加16.6°（P<0.001）,U1-SN角减小8.2°（P<0.001）,OPP-SN角减小5.3°（P = 0.012）,FH-PP角减小0.9°（P = 0.041）,差异均有统计学意义;U6-PP减小0.6 mm（P = 0.091）,L1-MP角减小0.6°（P = 0.058）,差异无统计学意义。 结论无托槽隐形矫治技术治疗高角型开 畸形能有效进行垂直向控制,使下颌平面逆时针旋转,获得良好疗效。     

锥形束CT与导板引导微创开髓精确性的体外研究

目的研究锥形束CT（CBCT）与三维打印导板引导微创开髓造成的偏移距离与偏移角度，探讨该操作的精确性。 方法收集40颗人离体单根双根管上颌第一前磨牙，开髓前进行CBCT扫描。对所有样本进行编号，通过随机数字表法将样本分为A、B两组，每组20颗牙，包括40个根管。微创开髓洞型采用"Truss"开髓洞型的设计。其中A组为三维打印导板引导开髓组，根据CBCT图像制作导板；B组为CBCT引导开髓组，根据CBCT图像确定 面开髓的位置与方向，于样本标记后直接开髓。两组样本开髓后，在CBCT图像中测量并计算各开髓孔在 面与髓角平面的面积、颊腭向与近远中向的偏移距离及偏移角度，使用SPSS 20.0软件进行统计学分析。 结果各组数据不满足正态分布及方差齐性，故采用Mann-Whitney U检验分析。开髓孔在 面平面的面积分别为A组（1.34 ± 0.18）mm²、B组（1.30 ± 0.15）mm²，差异无统计学意义（U=0.876，P=0.393）。髓角平面的面积分别为A组（1.74 ± 0.20）mm²、B组（1.67 ± 0.24）mm²，差异无统计学意义（U=1.290，P=0.194）。B组 面近远中偏移距离[（0.37 ± 0.26）mm]小于A组[（0.52 ± 0.30）mm]，差异具有统计学意义（U=2.237，P=0.024）。两组的 面颊腭向偏移距离、髓角颊腭向偏移距离、髓角近远中偏移距离、颊腭向偏移角度及近远中偏移角度间差异均无统计学意义（P>0.05）。 结论单独使用CBCT可精确引导常规根管解剖形态患牙的微创开髓，CBCT结合导板对引导微创开髓的精确性与单独使用CBCT相比无显著提高，且两种引导方法对微创开髓洞型的大小无明显影响。     

不同位置咬合高点对颞下颌关节面压力分布影响的实验力学研究

目的研究36 面不同位置的咬合高点对颞下颌关节（TMJ）负荷的影响。 方法在已建立的人冰鲜头颅TMJ负荷分析模型上，定义36 面无咬合高点，以及咬合高点位于 面近中尖、中央窝和远中尖时为工况一、二、三和四，记录并分析力学试验机加载后双侧TMJ上下腔关节面综合力度中心、压力集中区位置、压力峰值和压力接触面积等，使用方差分析方法进行结果的统计分析。 结果（1）双侧TMJ关节面负荷的综合力度中心均往右侧关节下腔关节面偏移，工况三时较为明显；关节面压力集中区位置变化表现为：左侧的各关节面有不同程度的位移，而右侧则相对稳定。（2）相较于工况一，工况二、三、四时，左侧TMJ上、下腔关节面表面压力峰值总体呈减小趋势（F_上 = 4.49，P_上 = 0.63；F_下 = 7.11，P_下 = 0.01），右侧TMJ上下腔关节面表面压力峰值差异无统计学意义（F_上 = 0.60，P_上 = 0.04；F_下 = 1.13，P_下 = 0.39）。（3）相较于工况一，工况二、三、四时，双侧TMJ上、下腔关节面接触面积变化均无统计学意义（P>0.05）。 结论36 面不同位置的咬合高点会影响TMJ关节面的受力形式，造成关节结构之间受力环境的改变。     

个性化上颌非对称旋转矫治上颌 平面偏斜畸形

目的评估上颌非对称旋转在矫正 平面偏斜不对称畸形患者中的应用。总结治疗面部不对称畸形患者的经验,为临床治疗面部不对称畸形提供参考。 方法选取32例 平面偏斜的面部不对称畸形患者,拍摄术前螺旋CT及术前、术后头颅正位片,术前在计算机辅助下模拟手术,设计个性化手术方案,不对称旋转上颌 平面,并将模拟数据用于手术中。采用配对t检验进行统计学分析比较术前、术后面部外形差异。 结果32例患者面部形态及功能均取得了良好的治疗效果,无术中及术后并发症发生,软硬组织取得良好对称性,面部外形协调美观。术后双侧上颌骨高度差异[（0.6 ± 0.5）mm]小于术前上颌骨高度差异[（4.7 ± 1.5）mm],差异有统计学意义（t= 15.172,P<0.001）。术后<平面偏斜度[（0.5 ± 0.5）°]小于术前<平面偏斜度[（4.4 ± 1.7）°],差异有统计学意义（t= 12.934,P<0.001）。术后非对称率[（0.7 ± 0.6）%]小于术前非对称率[（5.5 ± 1.7）%],差异有统计学意义（t= 15.640,P<0.001）。 结论（1）数字化计算机辅助外科技术能够模拟手术过程,设计手术方案,重建术后软硬组织形态并指导正颌手术的准确截骨;（2）上颌非对称旋转能够矫正上颌 平面偏斜畸形,达到面部软硬组织对称协调,改善面部不对称畸形。     

正畸治疗中磨牙的拔除和保留(三十八)——闭下颌第一磨牙拔牙间隙后牙槽嵴高度及牙根吸收的随访研究

目的:通过对正畸关闭下颌第一磨牙拔牙间隙后牙槽嵴高度及牙根吸收情况的随访,探讨关闭磨牙间隙后牙周健康的长期稳定性.方法:共观察下颌第一磨牙拔牙间隙37处,下颌第二磨牙牙根74个.测量矫治结束及随访时的下颌第二磨牙近中牙槽嵴高度以及第二磨牙冠根比,将测量值进行配对t检验.结果:随访时下颌第二磨牙近中牙槽嵴高度以及冠根比与矫治结束时相比,均没有显著性差异.结论:采用拔除第一磨牙后的第二磨牙近中平移技术,关闭拔牙间隙的远期稳定性较好,有利于维持邻牙的牙周健康,可以充分发挥第二磨牙的咀嚼功能,以实现替代第一磨牙的作用.     

Root trunk dimensions of 5 different tooth types.

The primary purpose of this study was to document mean, standard deviation, and range of root trunk dimensions of multirooted tooth types. A total of 412 extracted teeth were examined and classified as: maxillary first molars, maxillary second molars, maxillary first premolars, mandibular first molars, and mandibular second molars. The distance from the cementoenamel junction (CEJ) to the root groove and from the CEJ to the root division was measured. Mean CEJ to root groove distances ranged from 1.35 to 1.65 mm for maxillary first molars, from 1.49 to 1.89 mm for maxillary second molars, from 1.71 to 1.73 mm for maxillary first premolars, from 1.16 to 1.22 mm for mandibular first molars, and from 1.53 to 1.76 mm for mandibular second molars.     

Furcation depth and interroot separation dimensions for 5 different tooth types

The purpose of this study was to document mean, standard deviation, and range of furcation depth and Interroot separation dimensions of 5 multirooted tooth types. A total of 412 extracted teeth were examined and classified as: maxillary first molar, maxillary second molar, maxillary first premolar, mandibular first molar, and mandibular second molar. The furcation depth was measured at the level of the furcation dome and 3 and 5 mm apical to the dome. Interroot separation was measured 3 and 5 mm apical to the furcation dome. Mean furcation depth at the dome was 7.48 mm buccally and 6.67 mm mesiodistally for maxillary first molars; 6.69 mm buccally and 5.94 mm mesiodistally for maxillary second molars; 3.54 mm mesiodistally for maxillary first premolars; 7.96 mm buccolingually for mandibular first molars; and 7.46 mm buccolingually for mandibular second molars. Interroot separation dimensions 3 mm apical to the dome were: 2.58 mm buccally, 4.17 mm mesially, and 4.48 mm distally for maxillary first molars; 1.92 mm buccally, 3.89 mm mesially, and 4.04 mm distally for maxillary second molars; 2.47 mm mesially and 2.58 mm distally for maxillary first premolars; 3.15 mm buccally and 2.95 mm lingually for mandibular first molars; and 2.54 mm buccally and 2.75 mm lingually for mandibular second molars.     

Incidence of patent furcal accessory canals in permanent molars of a Turkish population

Aim To determine the incidence of patent furcal accessory canals in permanent molars of a Turkish population. Methodology Two‐hundred extracted teeth consisting of 50 maxillary first molars, 50 maxillary second molars, 50 mandibular first molars and 50 mandibular second molars from Turkish patients attending the Oral Surgery Department of the Faculty of Dentistry, ?stanbul University, ?stanbul, Turkey, were included in the study. After preparation of access cavities and removal of pulp tissue, the teeth were stored in 5.25% sodium hypochlorite for 1 h. Following double‐sealing of the access cavities, all tooth surfaces except the furcation regions were covered with nail varnish. The teeth were stored in 0.5% basic fuchsin for 1 week. The teeth were sectioned at the cemento‐enamel junction and the presence of patent furcal canals was established by examining the pulp chamber floor with a stereomicroscope (10×) to determine staining. Results Patent furcal accessory canals were detected in 24% of maxillary first molars, 16% of maxillary second molars, 24% of mandibular first molars, and 20% of mandibular second molars. No statistically significant differences were found between the tooth types. Conclusions In a Turkish population, the incidence of patent furcal accessory canals on the pulp chamber floor of maxillary and mandibular first and second molars ranged between 16 and 24%.     

Symmetry of Root and Root Canal Morphology of Maxillary and Mandibular Molars in a White Population: A Cone-beam Computed Tomography Study In Vivo

Introduction

The aim of the present study was to use cone-beam computed tomography (CBCT) to analyze root canal anatomy and symmetry of maxillary and mandibular first and second molar teeth of a white population.

Methods

A total of 201 patients who required CBCT examinations as part of their dental diagnosis and treatment were enrolled in the present study. Overall, 596 healthy, untreated, well-developed maxillary and mandibular molar teeth (161 maxillary first molars, 157 maxillary second molars, 117 mandibular first molars, and 161 mandibular second molars) were examined by CBCT to establish the symmetry in root and canal anatomy between right and left sides in the same patient by evaluating the number of roots and root canals and the root canal configuration.

Results

Three separate roots with 3 separate canals was the normal anatomy of maxillary first and second molars. Most mandibular first and second molars had 2 separate roots, and the majority had 3 canals. In the present study, first molars, both maxillary and mandibular, exhibited greater asymmetry than the second molars. Maxillary first molars were found to be symmetrical in 71.1% of patients, whereas maxillary second molars were symmetrical in 79.6%. The remaining 28.9% and 20.4% of patients, respectively, showed asymmetry. Around 30% of the mandibular first molars and 20% of the mandibular second molars showed asymmetry.

Conclusions

The results of the present study reported a percentage of symmetry that varied from 70%–81%. These variations in symmetry should be taken in high consideration when treating 2 opposite molars in the same patient, because their anatomy may be different in up to 30% of the cases.     

A scanning electron microscopic investigation of accessory foramina in the furcation and pulp chamber floor of molar teeth

Observations of the pulp chamber floor and furcation surface of human maxillary and mandibular first and second molars were made with the scanning electron microscopic to determine the incidence, size, and location of patent accessory foramina. Accessory foramina on both the pulp chamber floor and the furcation surface were found in 36% of maxillary first molars, 12% of maxillary second molars, 32% of mandibular first molars, and 24% of mandibular second molars. Mandibular teeth had a higher incidence (56%) of foramina involving both the pulp chamber floor and furcation surface than did the maxillary teeth (48%).     

Patterns of endodontic care for a Washington state population

Endodontic care, provided by 3,402 dental offices, was assessed from claims data maintained by the Washington Dental Service for 1999. Approximately 5.7 million dental procedures were provided to 880,317 patients by 2,796 general practitioners, 105 endodontists, and 494 other specialists. Of all dental services, 63,321 (1%) were endodontic procedures involving 52,911 (6%) patients. General dentists, endodontists, and other specialists performed 64.7%, 33.7%, and 1.6% of endodontic procedures, the majority of which were root canal therapy. The most frequent tooth types treated by root canal therapy were mandibular first molars (17.0%), maxillary first molars (15.2%), mandibular second molars (11.8%), maxillary second bicuspids (10.3%), maxillary second molars (9.1%), maxillary central and lateral incisors (8.8%), and mandibular second bicuspids (8.0%). Direct and indirect pulp caps by generalists and conventional retreatment and surgical therapy by endodontists made up the majority of the remaining endodontic services. Men had a greater procedure rate than women for most endodontic procedures.     

偏移投照技术与显微治疗诊治遗漏根管的疗效分析

目的分析根管治疗术后偏移投照技术与显微根管治疗的应用对遗漏根管的发现与治疗的临床疗效。方法选择需行初次牙髓治疗的下颌前牙、下颌前磨牙、下颌第一、二磨牙及上颌第一、二磨牙共360颗(分别为49、68、62、50、85、46颗)。常规拍摄术前正位根尖片,并于根治后拍摄正位及20°～30°偏位根尖片,通过对比分析,对可疑遗漏根管的患牙,在显微镜下寻找及治疗遗漏根管。结果经显微治疗,360颗患牙中25颗(6.9%)确诊为遗漏根管,各牙位依次为3、5、5、4、6、2颗,其中23颗患牙发现并成功充填遗漏根管,2颗根管可找到但不完全通畅;正位发现8颗(2.2%),偏位发现23颗(6.4%),术后偏移投照发现率明显高于正位(P<0.05)。结论根治术后偏移投照技术与显微根管治疗对遗漏根管的发现与治疗有较大的帮助。     

Dentoalveolar and skeletal changes associated with the pendulum appliance.

The purpose of the study was to examine the dentoalveolar and skeletal effects of the pendulum appliance in Class II patients at varying stages of dental development and with varying facial patterns (high, neutral, and low mandibular plane angles). Specifically, the amount and nature of the "distalization" of the maxillary first molars and the reciprocal effects on the anchoring maxillary first premolars and incisors were studied, as were skeletal changes in the sagittal and vertical dimensions of the face. Pretreatment and posttreatment cephalometric radiographs obtained from 13 practitioners were used to document the treatment of 101 patients (45 boys and 56 girls). The average maxillary first molar distalization was 5.7 mm, with a distal tipping of 10.6 degrees. The anchoring anterior teeth moved mesially, as indicated by the 1.8-mm anterior movement of the upper first premolars, with a mesial tipping of 1.5 degrees. The maxillary first molars intruded 0.7 mm, and the first premolars extruded 1.0 mm. Lower anterior facial height increased 2.2 mm; there was no significant difference in lower anterior facial height increase between patients of high, neutral, or low mandibular plane angles. In patients with erupted maxillary second molars, there was a slightly greater increase in lower anterior face height and in the mandibular plane angle and a slightly greater decrease in overbite in comparison to patients with unerupted second molars. Similar findings were observed in patients with second premolar anchorage versus those with second deciduous molar anchorage. The results of this study suggest that the pendulum appliance is effective in moving maxillary molars posteriorly during orthodontic treatment. For maximum maxillary first molar distalization with minimal increase in lower anterior facial height, this appliance is used most effectively in patients with deciduous maxillary second molars for anchorage and unerupted permanent maxillary second molars, although significant bite opening was not a concern in any patient in this study.     

Molar root furcation: morphometric and morphologic analysis

The objective of the present study was a morphometric and morphologic analysis of maxillary and mandibular first and second molars using three different techniques. Measurements of 207 maxillary molars (105 first and 102 second molars) and 207 mandibular molars (110 first and 97 second molars) were measured; root length, radicular trunk length (RTL), mesiodistal and buccolingual diameters (BLD) at the cementoenamel junction, inter-radicular angle (IRA) width, and furcal roof area (FRA) were recorded. No significant statistical correlations were found for most of these measurements, the only exception being the relationship between IRA/FRA, IRA/BLD in maxillary molars, and IRA/RTL in the maxillary first molar. Morphologic examination was carried out by stereo microscopy, light microscopy of undecalcified sections, and scanning electron microscopy. All of these techniques showed the complexity of the furcation area with a large number of anatomic irregularities and plaque-retentive structures that could hamper adequate cleaning during periodontal treatment.     

Patterns of bilateral agenesis of maxillary third molars and agenesis of other teeth

The purpose of this study was to investigate the patterns of bilateral agenesis of maxillary third molars and other tooth agenesis in Japanese orthodontic patients. A group of 262 subjects with bilateral agenesis of maxillary third molars (group A) was divided into three subgroups: group 1A consisting of 114 subjects without agenesis of mandibular third molars; group 2A, 31 subjects with unilateral agenesis of mandibular third molars; and group 3A, 117 subjects with agenesis of all third molars. As controls, 926 other subjects without third molar agenesis were selected (group C). Panoramic radiographs were mainly used to examine for tooth agenesis. The Chi square test and odds ratio were used to make statistical comparisons. The prevalence rates of agenesis of maxillary lateral incisors, mandibular incisors and maxillary and mandibular second premolars, and bilateral agenesis of maxillary lateral incisors and second premolars were significantly higher in any one of the third molar agenesis groups than in the control group. Characteristically, no significant increase in occurrence of bilateral agenesis of mandibular second premolars was demonstrated by the subjects with bilateral agenesis of maxillary third molars. Irrespective of whether unilateral or bilateral agenesis of mandibular third molars is present or not, the Japanese orthodontic patients with bilateral agenesis of maxillary third molars exhibited a significantly increased occurrence of unilateral or bilateral agenesis of maxillary lateral incisors, mandibular incisors and maxillary and mandibular second premolars, except for bilateral agenesis of mandibular incisors and second premolars.