上颌前牙区种植方案中角度设计的三维有限元分析

目的 采用有限元法观察分析不同种植体植入角度与不同角度基台联合运用时种植体周骨组织的应力分布及种植体的位移情况,为上颌前牙区种植修复方案的设计提供依据。方法利用锥形束CT（cone beam computed tomography, CBCT）建立包含部分上颌骨、种植体（4.3 mm×11.5 mm）、基台及上部修复体（氧化锆全瓷冠）的三维有限元模型,以种植体植入角度A,即种植体长轴与理想长轴之间的夹角 (0°、5°、10°、15°、20°、25°)和基台角度B,即基台长轴与种植体长轴之间的夹角(0°、5°、10°、15°、20°、25°)建立有限元模型。在模型上与牙冠长轴呈130°、舌侧切端下2 mm,模拟大小为178 N的力加载,采用Ansys13.0软件观察种植体周围皮质骨、松质骨的最大主应力值、分布情况和种植体的位移。结果建立了16个符合实际情况的不同种植修复方案的上颌中切牙种植义齿的三维有限元模型;各种修复方案的种植体—骨界面应力分布特点相同,应力集中在种植体颈部及根部;在相同的植入角度下,基台角度越大,种植体周围皮质骨、松质骨的最大主应力峰值及种植体位移峰值均越大。在相同的基台角度下,种植体的植入角度越大,种植体周围皮质骨、松质骨的最大主应力峰值及种植体位移峰值均越大;植入角度或基台角度大于20°时,种植体周围皮质骨、松质骨的最大主应力峰值及种植体位移峰值增加幅度较大。结论种植体的植入角度和基台角度均与种植体周围皮质骨、松质骨的最大主应力峰值及种植体位移峰值呈正相关关系,应尽量减小种植体的植入角度和基台角度,尤其是需要严格掌握种植体的植入角度。从应力、位移考虑,前牙区种植体植入角度和基台角度在20°以内为佳。大于20°时,应力有明显升高趋势,增加种植成功的风险。     

微螺钉种植体支抗与口外弓增强支抗临床疗效的对比研究

目的比较微螺钉种植体支抗与口外弓增强磨牙支抗的效果。方法选择上颌前突的患者30名,随机分为两组,分别采用种植体支抗和口外弓支抗,对两组治疗前后的X线头颅侧位片测量并通过Pancherz分析法进行对比分析,同时记录并比较两组的正畸疗程。结果种植支抗组较口外弓组在覆盖、磨牙关系以及上中切牙位置方面改善明显,其差异有显著性（P〈0．05）;种植支抗组较口外弓组上磨牙位置更为稳定（P〈0．05）,正畸疗程更短（P〈0．05）。结论种植支抗比传统口外弓支抗增强上颌支抗的效果更为理想。     

微螺钉种植体和口外弓增强支抗的临床对比研究

目的比较微螺钉种植体支抗和口外弓增强磨牙支抗的效果。方法选择上颌前突的患者32例,随机分为种植支抗组和口外弓组,每组16例。种植支抗组采用微螺钉种植体支抗,口外弓组采用口外弓支抗。记录并比较两组正畸疗程的差异。矫治前后均拍摄X线头颅定位侧位片,分析前牙覆盖、SNA角、U1-SN角、U1-NA距、U6-Ptm距5项头影测量参数的变化并比较两组间的差异。结果种植支抗组的正畸疗程平均为（20.06±2.02）个月,口外弓组平均为（22.17±1.76）个月,种植支抗组较口外弓组疗程缩短,疗程差异有统计学意义（t=3.158,P=0.004）。种植支抗组前牙覆盖的改善大于口外弓组（P=0.020）,上颌中切牙倾斜度和突度的改善显著大于口外弓组（P〈0.01）,磨牙近中移动的距离显著小于口外弓组（P=0.000）,两组间上颌基骨的位置变化无统计学差异（P=0.085）。结论微螺钉种植体支抗比口外弓支抗能更好地保护磨牙支抗,缩短正畸疗程。     

横腭弓-Nance弓联合支抗与口外弓增强磨牙支抗的比较

目的：比较研究横腭弓-Nance弓联合支抗与口外弓支抗对支抗磨牙的控制效果. 方法：选择20 例安氏Ⅱ类1 分类上颌前突的患者,随机分为2 组,分别使用横腭弓-Nance弓联合支抗和口外弓增强上颌磨牙的支抗,通过治疗前后X线头影测量分析,比较二者对磨牙的支抗控制效果.结果：联合支抗组磨牙平均前移1.87 mm,切牙内收4.89 mm;口外弓组磨牙平均前移1.34 mm,切牙内收5.04 mm,2 组间差异无显著性（P〉0.05）.结论：联合支抗可提供与传统口外弓强支抗同样强度的支抗作用,且制作简单,效果满意,患者易于接受.     

微型种植体与口外弓治疗成人骨性Ⅱ类错（牙合）的比较张雄单丽华赵士芳黄吉娜毛靖王虎中郭家平王蕾赵今史建陆微型种植体与口外弓治疗成人骨性Ⅱ类错（牙合）的比较

目的 比较微型种植体和口外弓作为强支抗在治疗成人骨性II类错（牙合）中的临床效果.方法 微型种植体支抗组16名,口外弓支抗组10名,收集两组治疗前后的X线头颅侧位定位片,通过X线头影测量比较两组的上下颌骨及上下颌牙齿的各角度、线距的变化.结果 两种方法在对上下颌骨的影响、覆（牙合）覆盖的控制上有相同的效果,但对上颌前后牙的移动上两种方法有明显区别（P〈0.05）,上颌磨牙近中移动量分别为1.1mm（微型种植体组）和2.6mm（口外弓组）,上颌切牙内收量8.9mm（微型种植体组）和5.5mm（口外弓组）.结论 两种加强支抗的方法在正畸治疗中均可获到较好的治疗效果,但微型种植体支抗在上颌磨牙的近中移动和上颌切牙的内收上更具有优势.     

微型种植体与口外弓治疗成人骨性Ⅱ类错的比较

目的比较微型种植体和口外弓作为强支抗在治疗成人骨性II类错中的临床效果。方法微型种植体支抗组16名,口外弓支抗组10名,收集两组治疗前后的X线头颅侧位定位片,通过X线头影测量比较两组的上下颌骨及上下颌牙齿的各角度、线距的变化。结果两种方法在对上下颌骨的影响、覆覆盖的控制上有相同的效果,但对上颌前后牙的移动上两种方法有明显区别(P0.05),上颌磨牙近中移动量分别为1.1mm(微型种植体组)和2.6mm(口外弓组),上颌切牙内收量8.9mm(微型种植体组)和5.5mm(口外弓组)。结论两种加强支抗的方法在正畸治疗中均可获到较好的治疗效果,但微型种植体支抗在上颌磨牙的近中移动和上颌切牙的内收上更具有优势。     

腭侧螺旋推簧配合口外弓推磨牙向后的临床研究

目的：探讨腭侧螺旋推簧配合口外弓矫正器推磨牙向后的临床应用。方法：选择安氏Ⅱ类错He病例30例，采用腭侧螺旋推簧配合口外弓矫正器推磨牙向后，通过头影测量和模型分析，记录上颌切牙、磨牙向后移动的距离，有牙覆盖，双尖牙区和磨牙区宽度的变化。结果：上切牙腭向移位3．2mm，磨牙向后移动4．2mm，覆盖减小2．9mm，双尖牙区增宽1．4mm，磨牙区增宽1．6mm。结论：腭侧螺旋推簧配合口外弓矫正器能有效的远中移动上颌磨牙。     

酸蚀对自黏结树脂水门汀与牙本质黏结强度的影响

目的:评价酸蚀预处理对自黏结树脂水门汀Unicem、G-Cem、Clearfil SA Cement、BisCem与牙本质微拉伸黏结强度的影响。方法:选用人无龋离体第三恒磨牙32颗,用低速切片机将选用磨牙冠1/4处沿垂直于牙体长轴方向切开,暴露牙本质。实验组在牙本质表面涂布37%磷酸,冲洗、吹干,对照组不做处理。然后将各组与直径为5 mm、高为4 mm的树脂块分别用 Unicem、G-Cem、Clearfil SA Cement、BisCem进行黏结。水浴24 h后,用低速切片机将样本切割成约1 mm×1 mm×8 mm条状,再进行微拉伸测试,并通过扫描电镜观察黏结界面。采用SPSS16.0软件包对数据进行统计学分析。结果:Unicem组（12.9±3.2） MPa、G-Cem组（11.7±2.6） MPa及Clearfil SA Cement组（10.9±2.3） MPa与牙本质的微拉伸黏结强度显著高于BisCem组（6.8±2.4） MPa（P<0.05）。酸蚀预处理后,Unicem组（9.2±2.5） MPa、G-Cem组（6.1±2.3） MPa及Clearfil SA Cement组（4.8±1.7） MPa黏结强度显著降低（P<0.05）,而BisCem组（7.1±2.9） MPa黏结强度无显著差异。结论:牙本质的表面酸蚀预处理降低了自黏结树脂水门汀G-Cem、Clearfil SA Cement及Unicem 的牙本质黏结强度,但对BisCem的牙本质黏结强度无显著影响。     

3种抛光方法对2种复合树脂边缘微渗漏的影响

目的评价3种抛光方法对2种复合树脂边缘微渗漏的影响。方法选择80颗离体恒前磨牙,在每颗牙的颊侧颈部釉-牙骨质交界处用高速涡轮机制备盒形单面洞,长和宽均为3 mm,洞深2 mm。使用3M Z350树脂和3M Z250树脂各充填40颗牙。按照充填材料不同,随机分为不抛光组、Sof-lex discs抛光系统组、Super-snap抛光系统组和金刚砂抛光车针修形后再用橡皮杯抛光组。实验样本冷热循环后,在2%亚甲基蓝溶液中浸泡 24 h,沿牙体长轴将充填体正中颊舌向纵行剖开,立体显微镜（×40）下观察剖面,采用Spot 4.6图像分析软件测量渗漏深度。采用 SPSS 17.0 软件包对各组的微渗漏程度和深度分别进行Mann-Whitney U 检验和Kroskal-Walis秩和检验。结果3M Z350各组的边缘微渗漏深度分别为（0.655±0.486）、（0.626±0.497）、（0.634±0.345）和（0.875±0.283） mm。3M Z250各组的边缘微渗漏深度分别为（0.785±0.553） mm、（0.763±0.491） mm、（0.789±0.308）mm和（0.942±0.318） mm。2种树脂充填后,3种抛光方法树脂边缘微渗漏程度和深度均有显著差异（P<0.05）。结论Sof-lex discs抛光系统、Super-snap抛光系统对复合树脂修复体边缘渗漏无显著影响。     

微种植体支抗与口外弓支抗应用于成年女性安氏Ⅱ类1分类错畸形的矫治效果

目的探讨应用口外弓或微种植体支抗矫治成年女性安氏Ⅱ类1分错畸形的临床效果。方法20例成年女性安氏Ⅱ类1分类错畸形患者,采用微种植体支抗(种植支抗组)或口外弓支抗(口外支抗组)结合直丝弓技术矫治,每组10例,采用Pancherz分析法进行治疗前后头影测量指标分析。结果矫治后2组上颌基骨位置没有明显变化,下颌均略微前调,差异没有统计学意义;种植支抗组上颌磨牙前移(1.91±0.69)mm,口外支抗组为(2.38±1.08)mm,差异无统计学意义(P>0.05);种植支抗组上颌磨牙压低(0.70±0.71)mm,口外支抗组上颌磨牙伸长(0.88±0.74)mm,差异有统计学意义(P<0.001);种植支抗组下面高减少(1.13±0.93)mm,口外支抗组增加(0.37±1.93)mm(P<0.05);口外支抗组下颌平面角增加(2.18±1.74)°,种植支抗组减小(1.51±2.76)°(P<0.01),种植支抗组上颌磨牙压低后带来了下颌向前向上旋转的改变。两组上颌中切牙都得到内收,并均有压低,差异无统计学意义(P>0.05)。结论种植支抗或传统口外弓支抗均可取得良好的支抗效果,内收上颌前牙,改善磨牙咬合关系,种植支抗在磨牙垂直向控制上更有优势。     

上颌尖牙腭侧埋伏阻生的锥形束CT定位诊断

目的应用锥形束CT（CBCT）探讨上颌腭侧埋伏阻生尖牙的埋伏特征及邻牙牙根吸收情况。方法选取南京医科大学附属口腔医院正畸科就诊的上颌尖牙腭侧埋伏阻生的青少年患者22例,获取CBCT三维数据,应用Dolphin imaging 11.0软件,分析腭侧埋伏尖牙的埋伏状况、与邻牙位置关系并分类,观察邻牙牙根的吸收情况。结果上颌腭侧埋伏尖牙大多近中、腭向倾斜阻生,近中异位以Ⅰ类和Ⅳ类较为多见,分别占30.8%和38.5%;近中倾斜角度多在53.8°~68.5°,腭侧异位距正中矢状面多在5.4~8.4 mm。年龄越大,上颌腭侧埋伏尖牙近中腭向异位越远,近中倾斜角度越大。84.6%的相邻侧切牙及19.2%的中切牙牙根与埋伏尖牙接触;50%的相邻侧切牙及15.4%的邻中切牙牙根吸收,相邻侧切牙吸收多位于根尖1/3,而相邻中切牙吸收多位于根中1/3;相邻切牙牙根吸收概率与腭侧埋伏尖牙与切牙间的最小距离呈反比关系。结论CBCT能在三维方向诊断上颌尖牙埋伏状况及与邻近组织的关系,准确判断邻牙根吸收情况,准确测量埋伏尖牙倾斜度及埋伏深度,为上颌腭侧埋伏尖牙的治疗提供指导。     

Dentoskeletal effects of a temporary skeletal anchorage device–supported rapid maxillary expansion appliance (TSADRME): A pilot study

Objective:To quantitatively evaluate maxillary skeletal expansion using cone-beam computed tomography (CBCT) images and propose a novel way to quantify the dental tipping effects of temporary skeletal anchorage device–supported rapid maxillary expansion appliance (TSADRME).Materials and Methods:Images from 25 patients receiving rapid maxillary expansion with incorporated temporary skeletal anchorage devices (TSADs) before activation (T1) and after removal (T2) were analyzed to detect dentoskeletal changes.Results:A significant increase from T1 to T2 was found for all linear measurements except buccal maxillary width at the canines. The greatest buccal expansion was at the first molar, decreasing anteriorly. However, the greatest palatal expansion was at the first premolar. All younger subjects (8–16 years old) exhibited less dental tipping and greater expansion overall compared with the older subjects. There was great variability in dental tipping of first molars (mean = 4.31°), with some subjects demonstrating mild uprighting of these teeth.Conclusions:The TSADRME appliance is an effective, clinically useful device that results in mild molar tipping and may positively affect expansion in the area of TSAD placement.     

支抗控制在双颌前突畸形矫治中的作用

目的 研究支抗控制在滑动直丝弓技术矫治双颌前突畸形中的作用。方法 利用国产直丝弓托槽，滑动技术矫治双颌前突畸形患者30例，使用口外唇弓和不使用口外唇弓者各15例，均拔除4颗第一双尖牙，均采用一步法关闭拔牙间隙。将矫治前后的头颅侧位定位片进行对比分析，其变化量进行独立t检验。结果 矫治后戴口外唇弓组争不戴口外唇弓组上颌磨牙分别前移3．21mm和4．67mm；下颌磨牙分别前移3．32mm和5．21mm；两组的差异有统计学意义（P〈0．01）。前牙内收量戴口外弓组上颌为5．19mm，下颌为4．43mm；不戴口外弓组上颌为3．43mm。下颌为2．62mm。两组的差异有统计学意义（P〈0．01～0．001）。结论 口外唇弓在使用国产直丝弓托槽，运用滑动机制矫治双颌前突畸形中较有效地保护了后牙支抗，从而减少面部突度。     

Skeletal and dental effects of molar distalization using a modified palatal anchorage plate in adolescents

Objective:To evaluate and compare skeletal effects and the amount of molar distalization in maxilla using modified palatal anchorage plate (MPAP) vs headgear appliances in adolescent patients.Materials and Methods:Pre- and posttreatment lateral cephalograms of 45 Class II malocclusion patients were analyzed; 24 were treated with MPAP appliances (age, 12.4 years) and 21 with headgear (age, 12.1 years). Fixed orthodontic treatment started with the distalization process in both groups. Thirty-two variables were measured and compared between both groups using multivariate analysis of covariates.Results:There was no significant main effect of the appliance type on the treatment results (P  =  .063). Also, there was no significant main effect of the appliance type on both pre- and posttreatment comparisons (P  =  .0198 and .135, respectively). The MPAP and headgear groups showed significant distalization of maxillary first molars (3.06 ± 0.54 mm and 1.8 ± 0.58 mm, respectively; P < .001). Sagittal skeletal maxillomandibular differences were improved after treatment (P < .001), with no significant differences between the two groups. No significant difference in treatment duration was found between the groups.Conclusions:The MPAP showed a significant skeletal effect on the maxilla. Both MPAP and headgear resulted in distalization of maxillary first molars. Therefore, it is recommended that clinicians consider the application of MPAP, especially in noncompliant Class II patients.     

Class II treatment by palatal miniscrew-system appliance: A case report

This case shows that using a rapid palatal expander (RPE) and then a pendulum appliance anchored to palatal miniscrews is an option for improving treatment management in a noncompliant patient requiring maxillary expansion and molar distalization in the late mixed dentition. First, an RPE was used to expand the maxillary arch. Then, a modified pendulum appliance was used to distalize the maxillary first permanent molars. Optimal positioning of two palatal miniscrews enabled both appliances to be supported by skeletal anchorage. Treatment was finished using multibracket fixed appliances, and after 2 years, skeletal Class I as well as dental Class I canine and molar relationships were achieved.     

Treatment of Class II high angle malocclusions with the Herbst appliance: a cephalometric investigation.

The purpose of this study was to examine the results of treatment of Class II malocclusions by using two different designs of the Herbst appliance. Cephalometric records from lateral headplates of 19 consecutively treated Class II cases were evaluated. The headplates were taken before and after the treatment stage in which the Herbst appliance was used. The patients were divided into two groups: the first group, normohypodivergent, was treated with the Herbst appliance attached to bands; the second group, hyperdivergent, was treated with the Herbst appliance attached to acrylic splints in which a high-pull headgear was also used. The results were compared between these groups and with a control group age-matched from Bolton standards to match the changes in the Herbst samples against what might be expected in case of normal growth during similar periods of time. The results of the investigation revealed the following: (1) 9 months of treatment resulted in Class I dental arch relationships in all 19 cases; (2) the Herbst appliance attached to bands did not significantly modify the vertical growth pattern of the normohypodivergent patients; and (3) in hyperdivergent patients, the use of a Herbst appliance attached to acrylic splints in conjunction with the use of a high-pull headgear allowed a better control of the vertical dimension, as assessed by the cephalometric parameters (FA, FMA, Go-Gn-SN). The clinician should be aware of the different dentofacial changes induced in the vertical plane by different designs of the Herbst appliance to better program treatment strategy.     

丹参对大鼠正畸牙牙周组织TGF-β1表达的影响

目的:观察丹参注射液对大鼠正畸牙牙周组织TGF-β₁蛋白的表达变化。方法:选取SD雄性大鼠192只,随机分为丹参+加力组(A)、单纯加力组(B)、丹参对照组(C)和空白对照组(D)。A、B 2组再根据加力时间点建立正畸牙移动模型。A、C 2组与B、D 2组隔天于左侧上颌第一磨牙颊侧黏膜下分别注射丹参注射液及生理盐水。于加力后l、3、5、7、10、14 d分批处死大鼠,收集标本。体式显微镜测量大鼠正畸牙移动距离的改变,H-E染色观察牙周组织变化,免疫组织化学染色检测TGF-β₁蛋白的表达变化,采用SPSS17.0软件包对数据进行统计学分析。结果:除第1天外,A组TGF-β₁的表达均高于其余组别,3 d时TGF-β₁染色显著增强,5 d达高峰;与B组相比,第3、5、7天时间点TGF-β₁平均吸光度值分别为0.5181±0.0037、0.5857±0.0023和0.4363±0.0021,均具有显著差异（P<0.01）;与C组及D组相比,任何时间点均有显著差异（P<0.05）。结论:丹参注射液可通过改善牙周组织微循环,进而促进TGF-β₁蛋白的表达,可能是加速正畸牙移动的作用机制之一。     

Pulpal blood flow changes due to rapid maxillary expansion

Objective:To determine the pulpal blood flow (PBF) changes in anchorage teeth associated with the high forces of a rapid maxillary expansion (RME) appliance.Materials and Methods:The study was performed with 14 girls and 7 boys for a total of 21 patients between 10 and 15 years of age (mean, 13.1 ± 1.39 years). A modified acrylic bonded RME appliance was used as an expansion appliance. Laser Doppler flowmetry was used for the pulpal perfusion measurements. Records were taken from 42 upper central incisors, 28 canines, and 42 first molars at the following time intervals: just before expansion (T1); at the first week of expansion (T2); at the end of the expansion process (T3); and at the third (T4), seventh (T5), and 12th weeks of retention (T6). The data gained were statistically evaluated by parametric tests.Results:PBF values of the anchorage teeth were doubled at the first week of expansion; however, these values began to decrease because of separation of the median palatal suture. PBF values tended to reach their initial values during the retention period. Pulpal perfusion changes of all examined anchorage teeth were similar to each other from the beginning to the end of the evaluation.Conclusion:PBF changes that occur with RME are reversible.     

Herbst treatment with mandibular cast splints—revisited

Objective:The objective of this study was to reassess the dento-skeletal treatment effects and the amount of anchorage loss during reduced mandibular splint (RMS) Herbst treatment.Materials and Methods:One hundred consecutive Class II patients treated with a RMS-Herbst appliance were analyzed. The mean pretreatment age of the patients was 14.5 years, and the mean treatment time with the Herbst appliance was 8.1 months. Both before (T1) and after (T2) Herbst treatment a cephalometric measurement of lower incisor inclination, a sagittal occlusion analysis, and a dental cast analysis were performed. A comparison was performed with a historic Herbst control group treated with total mandibular cast splints (TMS).Results:During treatment the lower incisors proclined markedly (12.9° ± 4.6°). The amount of incisor proclination in the RMS group was, on average, 3.6° larger (P < .001) than in the TMS group. The lower incisor proclination increased from 11.9° (prepeak) to 14.3° (young adult). The level of professional experience of the practitioners performing the treatment did not influence the amount of incisor proclination significantly. The total available space in the lower arch increased by an average of 1.8 mm, and a space opened between the lower second premolars and lower permanent first molars in 62% of the present RMS-Herbst (average of 0.4 mm per side).Conclusions:Treatment with RMS-Herbst appliances leads to higher proclination of the lower incisors than does treatment with TMS-Herbst appliances; it also leads to an overall larger amount of anchorage loss.