CEREC CAD/CAM系统中生物仿造咬合面的精度测量

目的定量测量CEREC CAD/CAM系统中生物仿造咬合面与天然牙咬合面的变化。方法通过Infinite Focus扫描系统获取20个完整的上颌第一磨牙的超硬石膏模型的三维模型。在模型的三维坐标系统中测量近中舌尖最高点(lMPC)及中央窝最低点(lCP)相对近中颊尖最高点的高度以及过近中舌尖最高点和中央窝最低点直线与水平面之最小夹角(∠MPC)。随后在石膏模型上进行近中舌尖的嵌体窝洞预备。于CEREC椅旁系统之中利用生物仿造模式(biogeneric tooth model)自动生成嵌体设计并在瓷块中切割出修复体。瓷嵌体就位于石膏模型后置于Infinite Focus中扫描并测量相同的3个指标。通过t检验检测3组指标的差值是否具有统计学意义。通过Pearson相关性分析探索各指标的变异与牙尖斜度之间的关系。结果各指标间的变异分别为ΔlMPC=(101.87±33.21)μm,ΔlCP=(-201.72±55.28)μm以及Δ∠MPC=(4.66°±0.31°)。3组指标之差值均具有统计学意义(P<0.05)。三组指标的变异中只有Δ∠MPC与牙尖斜度存在明显相关性(P<0.01)。结论生物仿造模式自动生成之修复体咬合面与原天然牙咬合面仍存在明显差异。     

数字化口腔修复（15）--功能牙合道技术在CAD／CAM高嵌体修复中的应用（附临床病例）

目的：通过CEREC?椅旁CAD／CAM软件中的功能牙合道（ functionally generated path,FGP）技术修复1例二氧化锆高嵌体,比较CAD的3种模式（生物再造、虚拟牙合架、FGP）下所生成的牙合面之间的差异。方法：牙体预备后,按照标准程序扫描对颌牙和咬合状态下的颊侧,继而扫描动力学牙合印模,即FGP。在虚拟模型上执行上述CAD 3种模式的标准流程设计,并生成3种模式下的咬合面。利用椅旁CAM切削FGP二氧化锆高嵌体,临床试戴,完成粘接。结果：CAD的3种模式下所生成的牙合面形态之间存在差异, FGP形态优于生物再造,虚拟牙合架最差。临床上FGP二氧化锆高嵌体仅需微量调牙合,即可达到稳定的牙合关系,节省了椅旁时间,患者对于修复体满意。结论：在CEREC?椅旁CAD／CAM二氧化锆高嵌体修复中,FGP技术是一种消除牙合干扰的最优方法,优于是生物再造和虚拟牙合架。     

数字化技术在酸蚀症伴重度磨耗患者功能美学缺陷修复中的应用1例

牙磨耗、磨损、酸蚀症等多因素导致的非龋性牙体缺损在口腔临床中的发病率呈上升趋势,通常伴随着不同程度的口腔美学缺陷及功能障碍。对其进行全牙列固定修复咬合重建时,不仅要恢复牙列的形态和美观,更要实现咬合关系与整体口颌系统的协调。本文报道1例酸蚀症伴重度磨耗的病例,利用多模态数字化数据（口内扫描、面部扫描、电子面弓、下颌运动轨迹描记等）构建4D虚拟患者,制定全面的修复方案,进行不同牙齿的个性化微创修复,采用唇贴面、颊贴面、贴面、高嵌体、嵌体、全冠等多种修复体,完成数字化全牙列咬合重建治疗,为该疾病的诊治提供可视化、可全程质控的全局观诊疗策略。     

上颌颌板-上颌牙列扫描匹配方式对数字化转移上颌位置的影响

目的:研究在齿科设计软件中应用不同上颌颌板-上颌牙列扫描匹配方式对数字化转移上颌位置的影响。方法:使用下颌运动分析系统对10位受试者进行下颌运动记录,通过口内扫描获得上下颌数字模型及咬合关系。本实验共涉及5种上颌颌板-上颌牙列扫描匹配方式,包括：整体扫描组(ES组)、单次扫描组(SS组)与双面扫描组(DS组)、单次扫描匹配上颌组(SSU组)、双面扫描匹配上颌组(DSU组)。将口内扫描数据、上颌颌板-上颌牙列数字模型与下颌运动数据导入至CAD软件中,以完成数字化上牙合架,测量上颌左侧第一磨牙近中颊尖至虚拟牙合架左侧髁球距离、上颌右侧第一磨牙近中颊尖至虚拟牙合架右侧髁球距离、上颌中切牙近中切点至虚拟牙合架左、右髁球距离。每种方法重复3次,所得结果取平均值后进行统计分析。结果:通过上述5种方法转移的上颌位置,所测量的上颌左侧第一磨牙近中颊尖至虚拟牙合架左侧髁球距离、上颌右侧第一磨牙近中颊尖至虚拟牙合架右侧髁球距离、上颌中切牙近中切点至虚拟牙合架左、右髁球距离,无显著性差异(P>0.05)。结论:本实验选取的5种获得上颌颌板-上颌牙列数字模型的扫描匹配方式均可用于齿科设计软件中上颌位置的...     

下颌第一磨牙牙体缺损全冠修复的应力分析

目的：观察下颌第一磨牙根管治疗术后不同程度的远中牙合面（distal oeclusal简称DO）牙体缺损，在银汞合金或复合树脂修复后再用全冠修复的应力分析，了解牙体缺损程度对牙体抗折力的影响，比较两种修复DO洞是否有不同的影响。方法：通过三维激光扫描、三维造型设计建立下颌第一恒磨牙髓室壁未破坏的最小、中等、最大以及髓室壁部分破坏的最大远中黯面牙体缺损的三维有限元模型。观察4种模型4种载荷下牙本质Mohr应力分布，比较牙本质最大Mohr值。结果：在最大、垂直、斜向载荷下，两种修复体牙本质最大Mohr值均明显小于牙本质拉伸极限强度。在水平载荷下，两种修复体牙本质最大Mohr值均有急剧增加。银汞合金、全冠修复应力面积普遍大于复合树脂、全冠修复应力面积。牙本质最大Mohr值总的趋势复合树脂、全冠修复的大于银汞合金、全冠修复的。结论：在正常咬合下，下颌第一磨牙（36、46）DO牙体缺损髓室壁牙体组织未破坏，牙体预备体颊、舌侧厚度不少于1mm；髓室壁牙体组织部分破坏，牙体预备体舌侧厚度至少1mm、颊侧厚度至少2．5mm，临床可考虑用复合树脂、银汞合金修复再加全冠修复。在存在磨牙症情况下，应采取减轻黯力的措施。对较大面积牙体组织DO缺损且破坏到髓室壁的病例以复合树脂加全冠修复为好。     

正常接触位、下颌后退接触位咬合接触的计算机图像分析

目的 :研究正常牙合肌接触位及下颌后退接触位咬合接触的基本规律。方法 :采集 35名正常牙合肌接触位及下颌后退接触位的硅橡胶牙合记录 ,进行计算机图像分析。结果 :肌接触位 33人前牙无接触 ,单颌后牙区接触数为 16 .6± 7.2 ,所有受试者均为双侧接触。肌接触位咬合接触均在牙尖交错位重复出现。接触频率超过 5 0 %的部位位于上颌磨牙颊尖和舌尖的远中斜面 ,下颌磨牙颊尖和舌尖的近中斜面。下颌后退接触位所有受试者均为双侧接触 ,有接触的牙齿数目单颌单侧 2 .7± 0 .8,接触点数目单颌 8.0± 2 .3,前牙无接触 ,接触数目及比率从第二磨牙到第一前磨牙依次减少。接触频率超过 40 %以上的斜面上颌为前磨牙舌尖、磨牙远中舌尖及第二磨牙近舌尖的近中颊斜面 ,下颌为前磨牙及第二磨牙颊尖的远中舌斜面。结论 :以硅橡胶为记录材料准确采集到肌接触位及下颌后退接触位牙合记录 ,经计算机图像分析 ,得出其咬合接触的基本特征。     

第一磨牙的生理性磨耗

目的：通过对上、下颌第一磨牙不同部位生理性磨耗的观察，探讨磨耗特征及其生理意义。方法：５５１ 个上颌第一磨牙和６８６ 个下颌第一磨牙，根据磨耗程度分为轻、中、重度（ 绝对磨耗程度），根据单个牙上不同部位磨耗程度排序（ 相对磨耗程度），比较各部差别。结果： 上颌第一磨牙磨耗程度由重到轻排序：近、远舌尖＞ 近、远中边缘嵴＞ 近、远颊尖；下颌第一磨牙排序：远中尖、远中边缘嵴＞ 近、远颊尖＞ 远舌尖＞ 近舌尖、近中边缘嵴。结论：上颌第一磨牙以舌尖磨耗最重，而下颌第一磨牙则为远中部磨耗最重，可能与局部咬合力作用时间及作用强度有关。     

多数牙正锁牙合临床矫治

锁牙合是指上后牙舌尖的舌斜面与下后牙颊尖的颊斜面相咬合,或上后牙颊尖的颊斜面与下后牙舌尖的舌斜面相咬合,咬合面无接触,以正锁牙合更为多见。锁牙合主要表现在牙弓后段,早期不影响美观,常常不易被家长或患者本人发现。而多数牙正锁牙合所表现的牙齿颊舌向、垂直向及近远中方向的异常,易引起颞下颌关节异常、咬合平面偏斜以及颜面部不对称等。多数牙正锁牙合侧咀嚼功能较非锁牙合侧低,且这种错牙合畸形并不能随生长发育自行调整和改善,久而久之会增加骨性畸形程度和正畸治疗难度。多数牙正锁牙合早期通过简单装置将牙齿移动到正确的位置,可建立良好的咬合诱导,建立口周肌肉平衡,以诱导下颌的正常生理功能,避免骨性错牙合畸形的发生发展,建立和维持良好的口颌功能与健康。     

三维打印及功能引导路径技术获得诊断性全冠功能性[牙合]面形态初探

目的通过在三维打印诊断性全冠上运用功能引导路径(functional generated path,FGP)技术获得修复体功能性[牙合]面形态,探索减少修复体面调改量以及避免干扰的临床方法。方法选择2018年7月至2018年12月于北京大学口腔医学院·口腔医院修复科就诊、需行下颌第一磨牙全冠修复的患者10例,其中男性4例,女性6例,年龄(29.6±7.4)岁;进行基牙预备体模型扫描并获得数字化模型;分别为每例患者制作两种全冠修复体。试验组:制作三维打印聚乳酸基底冠和蜡面,通过口内FGP法直接获得具有功能接触形态的面,扫描后制作计算机辅助设计与辅助制作氧化锆全冠修复体;对照组:按照数据库及经验常规设计制作氧化锆全冠修复体。临床试戴后用逆向工程软件(Geomagic Sudio&Quality)对修复体[牙合]面调改前后的咬合接触位置及面积、咬合接触程度、面调改高度和体积等指标进行数字化定量分析,并对两组数据进行配对t检验。结果10例患者均顺利通过FGP法获得面形态。试验组修复体[牙合]面调改体积[(7.320±4.238)mm3]显著小于对照组[(20.178±9.650)mm3](P<0.05);调改前试验组咬合高点高度[(0.043±0.019)mm]显著低于对照组[(0.594±0.201)mm](P<0.05),咬合接触面积[(11.430±4.102)mm2]显著大于对照组[(4.808±3.223)mm2](P<0.05)。结论运用三维打印及功能引导路径技术可获得修复体[牙合]面的个性化功能接触形态,可比常规方法显著减少修复体[牙合]调改量并降低咬合高点。     

探讨全口义齿的理想咬合形态

咬合问题,包括下颌位置、下颌运动和牙齿接触三个问题,三者密切相关。本文着重讨论全口义齿的牙齿接触形态。本文所指的牙齿接触形态是下颌侧运动时的接触形态。多数人认为全口义齿的平衡(牙合)是标准(牙合)。1966年Gerbor提出的髁式后牙是根据杵和臼的原理设计的,特点是上颌牙的舌尖和下颌牙的中央窝在正中咬合时接触,而上下颊尖不接触。1973年Pound介绍了舌侧咬合,是由上颌牙的舌尖和下颌牙     

铸造支架联合NITI悬臂梁矫正舌倾下颌磨牙的临床效果评价

目的 评价NITI悬臂梁在矫正舌倾下颌磨牙中的临床效果。方法 选择16例单侧下颌第二磨牙舌倾的病例为研究对象,带垫铸造支架连接双侧下颌后牙,提供颌内支抗、解除咬合锁结,0.018英寸×0.025英寸或0.019英寸×0.025英寸NITI悬臂梁提供颊向旋转力矩和压低力。采用Graphpad Prism 6.0 软件对治疗前、后所测数据进行配对 t 检验。结果 所有患牙均获得直立,牙轴变化24°±1.2°（P<0.01）,近中舌尖到正中矢状面垂直距离变化（3±0.8） mm（P<0.05）,牙周状况良好,咬合关系稳定。结论 铸造支架联合NITI 悬臂梁可提供有效力学机制,矫正舌倾下颌磨牙。     

α桐酸对舌鳞状细胞癌CAL-27细胞的体外抑制作用

目的: 探讨苦瓜籽油中的α桐酸(α-eleostearic acid,α-ESA)对舌鳞状细胞癌CAL-27细胞增殖、迁移、凋亡的影响。方法: 将0、70、80、90、100、110、120 μmol/L的α-ESA培养CAL-27细胞后,用CCK-8法和流式细胞术分别检测加药24、48、72 h后细胞增殖抑制率和加药48 h后细胞凋亡率。再分别以0、80、100 μmol/L的α-ESA培养CAL-27细胞不同时间后,用细胞划痕实验检测加药24 h后细胞的迁移能力,Hoechst 33258染色在荧光显微镜下观察加药48 h后凋亡细胞形态。采用SPSS 21.0软件包对实验数据进行统计学分析。结果: α-ESA对CAL-27细胞的增殖抑制作用呈明显时间和浓度依赖性(P<0.05)。作用24、48、72 h后,半数抑制浓度(IC₅₀)逐渐降低,分别为(123.48±1.00)、(80.22±0.03)和(69.27±80.34) μmol/L。流式细胞检测结果显示,细胞凋亡率随着α-ESA浓度的增加而大幅增高(P<0.05)。培养24 h后,加入80、100 μmol/L的α-ESA的细胞划痕愈合率分别为(40.08±2.19)%、(22.06±2.04)%,显著低于对照组(74.74±2.17)%(P<0.01)。荧光显微镜下观察到致密浓染或碎块状亮蓝色荧光的细胞凋亡现象。结论: α-ESA能够抑制CAL-27细胞的体外增殖及迁移能力,并可诱导细胞凋亡,从而产生一定的抗肿瘤生长作用。     

Change of Lip and Occlusal Cant After Simultaneous Maxillary and Mandibular Distraction Osteogenesis in Hemifacial Microsomia

Background

The purpose of this study was to investigate the lip and occlusal cant changes in hemifacial microsomia (HFM) cases after simultaneous maxilla and mandibular distraction osteogenesis (DO) of the mandible.

Patients and Methods

Retrospective analysis of all HFM cases at Balaji Dental and Craniofacial Hospital were performed. Patient of either gender with all medical imaging records and pre and post-operative (6 months) facial photographs in natural head position were included in the study. The lip cant change was assessed by the angle of each labial commissure and the bi-pupillary reference line. The line joining the frontozygomatic unions and a parallel line is drawn at the level of anterior nasal spine. The occlusal plane is then traced. A vertical line is traced perpendicular to the frontozygomatic union. The deviation of the occlusal plane from the horizontal is measured as the occlusal cant and a change, between pre and post-operative records was considered as the angle and linear measurements.

Result

With the linear measurement, the mean change in occlusal cant was 7.18 ± 1.47 mm while for the mean change in lip cant was 3.31 ± 0.52 mm (P = 0.120). For the angular measurement, the mean angle change in occlusal cant was 13.86 ± 2.69° and mean change in angle of lip cant was 8.54 ± 0.7° (P = 0.01).

Discussion and Conclusion

For type1HFM, DO corrects the occlusal and lip cant. In present study, the lip cant change relative to occlusal cant change was 47.54 ± 10.71% in linear measurements while for angular measurements it was 63.19 ± 10.07% (P = 0.476; Pearson’s correlation coefficient = −0.241).keywords: Hemifacial microsomia, Distraction osteogenesis, Lip cant, Occlusal cant     

咬合引导的颌骨重建精确度分析及功能评价

目的: 探讨颌骨缺损重建术中移植骨定位的平面优先原则,确保新建的颌骨功能定位与咀嚼功能恢复,为临床治疗提供指导。 方法: 对60例颌骨缺损患者,通过数字化虚拟手术设计,确定平面的位置并以其作为参考平面,以咬合关系为引导,进行颌骨定位重建,最终完成种植修复。采集术后1个月和6个月时的CT数据,并与术前设计方案进行对比,分析移植骨就位和种植体植入的精确度,测定咬合力分布情况,进行功能评价。 结果: 术后1个月时,上颌骨移植腓骨和髂骨就位的精确度分别为(90.28±0.29)%和(89.87±0.41)%,下颌骨分别为(82.21±0.32)%和(89.52±0.18)%,上颌和下颌种植体的精确度分别为(91.72±0.21)%和(86.07±0.26)%。术后6个月时,上颌骨移植腓骨和髂骨就位的精确度分别为(89.24±0.20)%和(89.86±0.37)%,下颌骨分别为(75.39±0.25)%和(85.02±0.17)%,上颌和下颌种植体的精确度分别为(90.22±0.27)%和(85.57±0.31)%。单侧颌骨缺损的咬合力分布健侧为(68.14±8.32)%,患侧为(35.22±5.73)%;而双侧缺损的左、右两侧分别为(52.18±1.75)%和(47.82±2.41)%。 结论: 咬合引导的颌骨重建能够预先确定移植骨的空间位置、种植体的植入位点与方向,最终实现精准的咬合重建,恢复咀嚼功能,是颌骨功能性重建的有力保障。     

A Comparitive Evaluation of the Marginal Adaptation of Zirconium Coping and Nickel–Chromium Coping Using Shoulder Finish Line Design: An Invitro Study

Marginal adaptation is an important factor for long term clinical success of the restoration. This study aims to evaluate and compare the marginal adaptation of zirconium coping and nickel–chromium coping using the shoulder finish line design. For the purpose of this study 30 master dies were fabricated. A total of 30 copings were fabricated in which 15 zirconia copings and 15 Ni–Cr copings were fabricated. The copings obtained were seated on the die and marginal discrepancy between the metal die and the copings were then measured with Scanning electron microscope at magnification of ×50 and the findings were statistically analyzed. Mean and standard deviation values of marginal discrepancy of cervical margins of zirconia copings were 39.32 and 2.66 μm and Ni–Cr copings were 129.98 and 2.57 μm. Higher mean marginal gap (μm) is recorded in Ni–Cr copings compared to zirconia copings. The difference in mean marginal gap (μm) between the two copings is found to be statistically significant (P < 0.001). Within the limitation of this study it was concluded that higher mean marginal gap (μm) was recorded in Ni–Cr copings compared to zirconia copings. The difference in mean marginal gap (μm) between the two copings is found to be statistically significant (P < 0.001).     

ABRASION WEAR RESISTANCE OF DIFFERENT ARTIFICIAL TEETH OPPOSED TO METAL AND COMPOSITE ANTAGONISTS

One of the most important properties of artificial teeth is the abrasion wear resistance, which is determinant in the maintenance of the rehabilitation''s occlusal pattern.

Objectives:

This in vitro study aims to evaluate the abrasion wear resistance of 7 brands of artificial teeth opposed to two types of antagonists.

Material and methods:

Seven groups were prepared with 12 specimens each (BIOLUX – BL, TRILUX – TR, BLUE DENT – BD, BIOCLER – BC, POSTARIS – PO, ORTHOSIT – OR, GNATHOSTAR – GN), opposed to metallic (M – nickel-chromium alloy), and to composite antagonists (C – Solidex indirect composite). A mechanical loading device was used (240 cycles/min, 4 Hz speed, 10 mm antagonist course). Initial and final contours of each specimen were registered with aid of a profile projector (20x magnification). The linear difference between the two profiles was measured and the registered values were subjected to ANOVA and Tukey''s test.

Results:

Regarding the antagonists, only OR (M = 10.45 ± 1.42 μm and C = 2.77 ± 0.69 μm) and BC (M = 6.70 ± 1.37 μm and C = 4.48 ± 0.80 μm) presented statistically significant differences (p < 0.05). Best results were obtained with PO (C = 2.33 ± 0.91 μm and M = 1.78 ± 0.42 μm), followed by BL (C = 3.70 ± 1.32 μm and M = 3.70 ± 0.61 μm), statistically similar for both antagonists (p>0.05). Greater result variance was obtained with OR, which presented the worse results opposed to Ni-Cr (10.45 ± 1.42 μm), and results similar to the best ones against composite (2.77 ± 0.69 μm).

Conclusions:

Within the limitations of this study, it may be concluded that the antagonist material is a factor of major importance to be considered in the choice of the artificial teeth to be used in the prosthesis.     

喷砂联合飞秒激光蚀刻对纯钛表面理化性能的影响

目的 纯钛表面喷砂处理后,利用飞秒激光蚀刻形成表面周期性微结构,初步评价其表面理化性能。方法 12个直径10 mm、厚4 mm的纯钛圆片样本,根据表面处理方式,随机分为喷砂组（S组）、喷砂酸蚀组（SA组）、喷砂飞秒激光蚀刻组（SL组）。采用扫描电镜（SEM）、X射线能谱仪（EDS）、激光共聚焦显微镜（CLSM）、高温润湿角测量仪,分析3种钛表面的表面形貌、化学成分、粗糙度及润湿性。采用 SPSS19.0 软件包对数据进行统计学分析。结果 SEM及CLSM观察显示,飞秒激光在喷砂钛表面蚀刻出均匀整齐的周期性微米级结构,SL组钛表面呈二级粗糙度复合结构。EDS分析显示,SL组钛表面Al元素减少（SL组4.37%SA组0.32>S组0）。表面粗糙度测量显示,SL组钛表面粗糙度显著增大 [SL组（7.33±0.38）μm>SA组（1.08±0.12）μm>S组（1.05±0.14）μm]（P<0.001）;表面静态接触角测量显示,SL组钛表面静态接触角显著减小 [SL组（34.4±2.5）°P<0.001）。结论 喷砂联合飞秒激光蚀刻纯钛表面具有优良的理化性能,是一种具有潜力的钛种植体表面改性技术。     

Morphological measurements of anatomic landmarks in human maxillary and mandibular molar pulp chambers

The aim of this in vitro study was to measure critical morphology of molar pulp chambers. One hundred random human maxillary and mandibular molars (200 teeth in total) were used. Each molar was radiographed mesiodistally on a millimeter grid. Using a stereomicroscope, the measurements were read to the nearest 0.5 mm. Results were as follows (mean, mm): pulp chamber floor to furcation, maxillary = 3.05 +/- 0.79, mandibular = 2.96 +/- 0.78; pulp chamber ceiling to furcation, maxillary = 4.91 +/- 1.06, mandibular = 4.55 +/- 0.91; buccal cusp to furcation, maxillary = 11.15 +/- 1.21, mandibular = 10.90 +/- 1.21; buccal cusp to pulp chamber floor, maxillary = 8.08 +/- 0.88, mandibular = 7.95 +/- 0.79; buccal cusp to pulp chamber ceiling, maxillary = 6.24 +/- 0.88, mandibular = 6.36 +/- 0.93; and pulp chamber height, maxillary = 1.88 +/- 0.69, mandibular = 1.57 +/- 0.68. The pulp chamber ceiling was at the level of the cementoenamel junction in maxillary, 98%, and mandibular, 97% of the specimens. The measurements showing the lowest percentage variance were buccal cusp to furcation (approximately 11%) and buccal cusp to pulp chamber ceiling (approximately 14%). The measurements were similar for both maxillary and mandibular molars.     

Versatility of Titanium 3D Plate in Comparison with Conventional Titanium Miniplate Fixation for the Management of Mandibular Fracture

Background

In the present study, 20 patients with mandibular fracture were included to evaluate the versatility of titanium 3D plate in comparison with conventional titanium miniplate fixation.

Methods

The patients were alternatively allocated to either the 3D plate group or Miniplate group. The patients were evaluated for the clinical assessment of mobility after fixation, pre and post-surgical occlusal relationship, adequacy of reduction on post operative radiograph and any post surgical complications.

Results

All 25 fractures in 20 patients were found to be adequately fixed when checked intra-operatively. No post-operative IMF was required in either of the groups. The mean radiographic score at post operative time interval in Miniplate group was found to be 2.80 ± 0.42 and in 3D Plate was found to be 2.90 ± 0.32. The mean radiographic score at 3 months time interval in Miniplate group was found to be 2.70 ± 0.48 and in 3D Plate was found to be 2.70 ± 0.48. Radiolucency at 3 months period was found in 1 patient (10%) in the miniplate group and it was not found in any patients in the 3D plate group. None of the patients in both the groups had complications of non-union or mal-union. In miniplate group, 2 patients (20%) had infections and in 3D plate group 1 patient (10%) had infection. 3 patients in miniplate group had occlusal discrepancies (30%) and 1 patient in 3D plate group had occlusal discrepancies (10%). Overall, complications were found in 6 patients (60%) in miniplate group and 2 patients (20%) in 3D plate group. The data when compared was statistically significant (P < 0.05).

Conclusion

The 3D plating system was found to be advantageous over conventional miniplates. It uses lesser foreign material, reduces the operation time and overall cost of the treatment. Thus 3D plate can be used as an alternative to conventional miniplates. The system is reliable and effective treatment modality for mandibular fractures.     

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。