牙病治疗后产生折裂的原因分析

目的为预防干髓术和根管治疗术后牙体折裂问题提供科学、有效的方法.方法本文统计分析口腔门诊牙髓病和根尖周病患者2736例,3659颗牙,接受治疗后发生牙体折裂811颗,将牙体折裂按牙位进行分类统计.结果牙体折裂率23.45%,按牙位依次是上颌第一磨牙37%,下颌第一磨牙30%,上颌第二磨牙20.5%,下颌第二磨牙9.5%,前磨牙7.6%.结论干髓术和根管治疗术后牙体折裂原因除与牙体解剖特点相关外,龋坏程度、洞型特点、治疗技术、材料选择等都成为牙体折裂的关键因素,并提出了预防和处理牙体折裂的主要措施.     

有限元法建立下颌第一磨牙模型及受力分析

目的：建立下颌第一磨牙的三维有限元模型，并观察牙齿各部位应力分布情况。方法：离体下颌第一磨牙经CT扫描及图像处理，通过特定的有限元软件建立三维有限元模型；在该模型上模拟牙咬合情况进行垂直和侧向加载，计算出牙体部及根管壁各部位的最大拉应力，最大压应力和能量应力。结果：下颌第一磨牙的应力最大值出现在直接加载处，倾斜加载比垂直加载引起的应力大，自冠方向根方，各部位最大应力逐步减少，在髓底根管口处有一上升峰值，尤以倾斜加载时更为显著，管壁的应力大小牙体的应力，变化趋势与牙体的应力相似，结论：采用有限元法分析牙齿各部位的应力情况，是一种简捷，有效，可靠且安全的方法。     

三种不同材料的带桩高嵌体修复上颌第一前磨牙的三维有限元分析

目的：建立三组不同材料设计下的带桩高嵌体修复上颌第一前磨牙三维立体模型,研究该类患牙临床上是否适合选择带桩高嵌体修复,以及选择何种材料的带桩高嵌体修复。方法：利用口腔科专用New Tom锥形束CT扫描离体上颌第一前磨牙,获得CT图像数据;利用Mimics10.0软件得到上颌第一前磨牙三维图形;利用SolidWoks2013及其插件SolidWorks Simulation,建立上颌第一前磨牙三组三维有限元模型,并进行网格划分。模型A：氧化锆桩与氧化锆高嵌体组合。模型B：氧化锆桩与聚合瓷高嵌体组合。模型C：氧化锆桩与金合金高嵌体组合。根据得出的应力云图,分析三组修复体及牙体组织的应力分布情况。结果：①不同材料的带桩高嵌体修复后,无论是垂直向还是斜向加载,等效应力主要集中在力量加载部位、牙体舌侧牙颈部桩的桩/嵌体界面,在桩尖区无明显的应力集中;应力峰值低于牙本质抗拉强度的最低阈值;②无论垂直向还是斜向加载,不同材料嵌体的等效应力峰值为：氧化锆>金合金>聚合瓷。结论：①可以采用带桩高嵌体修复上颌第一前磨牙;②牙体组织的应力分布受材料影响,临床上应尽量选择弹性模量与牙本质相近的聚合瓷材料,以避免应力集中。     

Clearfil SE Bond以及Super Bond C和B粘接纵折牙后的应力分析

目的 指导折裂牙粘接材料的选择.方法 以美国商用有限元系统ALGOR软件建立下颌第一磨牙纵折三维有限元模型,分别以Clearfil SE Bond以及Super Bond C和B粘接折裂牙,而后施加垂直和倾斜载荷以获取折裂牙的应力分布情况.结果 纵折牙粘接回植后承受的应力及其变化趋势接近于健康牙;而以Clearfil SE Bond粘接治疗的牙体,承受应力变化的能力优于Super Bond C和B.结论纵折牙回植应选用与牙本质弹性模型更为接近的粘接材料.     

不同冠根比例对根管壁应力影响的分析

目的 应用有限元法观察牙槽嵴高度改变与根管管壁应力变化的关系。方法 在已建立下的下颌第一磨牙实验模型上，模拟牙槽嵴高度降低1／4，1／3和1／2建立修改模型，并在个性模型上垂直和侧向加载，计算牙齿及根管壁各部位的最大能量应力。结果 管壁各部应力变化的趋势与牙体各部应力变化趋势，但管壁应力小于牙体部管壁各部位的最大能量应力。结果 管壁各部应力变化的趋势与牙体各部应力变化趋势相似，但管壁应力小于牙体部应力。原模型与修改模型与根管口咱的应力值接近，随之原模型的应力明显降低；而修改模型的应力在根上1／3处达到最大，且固定高度越低，产生的应力越大，应力下降也越缓慢。侧向应力大于垂直应力，且固定高度越低，差异越明显。结论 牙槽嵴高度的改变，将引起根管壁应力的变化，两者间呈反比例关系。     

不同补偿曲线的上颌全口义齿基托的应力分布状况

目的:研究补偿曲线对上颌全口义齿基托应力分布的影响,为预防上颌全口义齿基托折裂和上颌全口义齿修复时优化设计提供理论依据。方法:用三维有限元应力分析法研究不同补偿曲线时上颌全口义齿基托应力及其分布状况。结果:前牙加载时,Ⅳ号模型切牙乳突区压应力最大;单侧后牙加载时,Ⅲ号模型腭顶、腭皱襞区压应力最大;双侧后牙加载时,Ⅰ号模型唇系带切迹、切牙乳突区压应力最大;全牙列加载时,Ⅰ号模型唇系带切迹区压应力最大。结论:在牙合力作用下,正常补偿曲线较异常补偿曲线的上颌全口义齿基托应力水平较低。提示补偿曲线正常的上颌全口义齿基托应力分布更加合理,义齿修复前应对下颌天然牙进行调牙合、重建正常的牙合曲线。     

侧向(牙合)力对楔状缺损充填材料应力分布的影响

目的 研究楔状缺损充填治疗后,侧向(牙合)力作用对充填材料的应力分布影响.方法 建立含楔状缺损的上颌第一前磨牙三维有限元模型,在模型的缺损部分用模拟玻璃离子材料进行充填;对模型施加不同方向的载荷,对充填体部分进行应力分析.结果 当(牙合)力方向与牙体长轴平行时,充填体受到的应力较小.当(牙合)力方向与受力牙尖斜面垂直时...     

后牙牙折内外固定治疗的临床体会

牙折是牙体大面积龋损、死髓或牙髓治疗后未能及时全冠修复 ,由于创伤牙合等因素作用导致牙体折裂 ,往往需要拔除而造成牙的丧失。牙折治疗的难点在于牙髓治疗和修复过程中牙体的进一步侵入 ,保护不当可使牙折纹进一步发展造成治疗失败。本文就后牙牙折的保存治疗提出一种内外固定方法 ,提高患牙治疗的成功率。资料与方法1 一般资料　选取 5 1例患者共 5 1颗牙折后牙 ,牙体Ⅰ°松动 ,牙折片与牙体间松动 <Ⅱ° ,牙周情况尚好。其中男性 32人 ,女性 19人 ,年龄 2 5～ 6 1岁。上颌第一前磨牙 7颗、第二前磨牙 5颗、第一磨牙 12颗、第二磨牙 6…     

植入位点不同对颧骨种植义齿种植体周骨应力分布影响的研究

目的探讨植入位点不同时颧骨种植义齿种植体-骨界面的应力分布规律。方法计算机模拟建立上颌后牙区重度萎缩三维有限元模型,分别在第一前磨牙区、第二前磨牙区、第一磨牙区和第二磨牙区模拟颧骨种植义齿修复。进行垂直向、颊向30°和舌向30°加载100 N,统计分析植入位点不同时颧骨种植义齿种植体-骨界面的应力。结果1）第一前磨牙区颧骨种植体颊侧暴露较多,与临床不符。2）上颌后牙区拉应力峰值比较：选择第二磨牙区植入时最大,第二前磨牙区次之,第一磨牙区最小。上颌后牙区压应力峰值比较：选择第二磨牙区植入时最大,第一磨牙区次之,第二前磨牙区最小。颧骨区拉应力及压应力峰值比较：选择第二前磨牙区植入时最大,第一磨牙区次之,第二磨牙区最小。结论选择第一磨牙区颧骨种植义齿修复较好。     

牙体缺损程度对后牙桩核冠修复牙本质应力影响的三维有限元分析

目的:比较上颌第一磨牙不同程度牙体缺损桩核冠修复后牙本质应力分布情况,探讨牙体剩余量与牙本质应力分布之间的关系。方法:通过磨片法建立上颌第一磨牙桩核冠有限元模型,比较上颌第一磨牙4种不同程度牙体缺损桩核冠修复后的牙本质应力分布情况。结果:后牙牙体水平向缺损量超过其牙冠牙体量1/2时,牙本质应力峰值较高,缺损量在牙冠牙体量1/2以内,对应力峰值无显著影响。结论:当水平向牙体剩余量大于1/2时,剩余牙体组织所受应力较大,上颌第一磨牙的腭根根分叉处是根折的危险区域。     

不同粘结剂对纵折牙根粘结后再植的疗效观察

目的：通过2种粘结剂处理纵折牙根进行粘结后再植术，了解不同黏结剂对后牙纵折愈合类型的影响。方法：3只Beagle犬的前磨牙48个牙根，分成3组，分别用Clearfil SE Bond（CE组，n=18）和SuperBond C＆B（SE组，n=18）进行粘结后再植，与正常牙根再植组（CC组，n=12）进行对照。术后16周处死动物，采集牙根一牙槽骨标本，按照”8等分法”和Andreasen愈合标准，记录各位点组织愈合情况，按有利愈合和不利愈合分类量化各组组织学愈合类型，并对各组牙根余留半径长按照0-4级评分，比较有效愈合率和余留牙根半径。结果：CE、SE、CC三组有效愈合率分别为：51％、31％、59％。余留半径评分分别为：3．38、2．47、3．59。CE组比SE组更能有效促进纵折牙根的愈合。结论：Clearfil SE Bond AP-x粘结系统能有效降低炎症性吸收和置换性吸收的发生率，提高后牙纵折粘结后再植术的手术成功率。     

2种粘接剂用于前牙断冠再接的剪切力评价

目的比较2种粘接剂用于前牙断冠再接时的剪切力。方法自制上颌恒中切牙冠折模型40个,随机分为A、B组,分别采用日本可乐丽菲露两步法粘接剂Clearfil SE Bond和一步法粘接剂Clearfil S3 Bond及相同的复合树脂Clearfil AP-X进行断冠再接。将再接后的样本置于万能试验机加载台上,持续加力至牙冠折断,记录牙冠断裂时的剪切力值。结果A、B组断冠再接后的剪切力分别为（324.32±65.91）N、（263.08±55.88）N。A组断冠再接后的剪切力明显高于B组,2组间有统计学差异（t=3.17,P=0.000）。结论两步法粘接剂Clearfil SE Bond用于前牙断冠再接后的剪切力优于一步法粘接剂Clearfil S3 Bond。     

The effect of current-generation bonding systems on microleakage of resin composite restorations.

OBJECTIVE: The aim of this study was to determine the microleakage of current-generation dentin bonding systems in Class II resin composite restorations. METHOD AND MATERIALS: Class II (occlusodistal or occlusomesial) cavity preparations with a gingival margin 2 mm apical to the cementoenamel junction were prepared on 70 noncarious, extracted human premolar teeth. Teeth were randomly divided into five groups and treated with different-generation bonding systems (Optibond FL, Gluma One Bond, Clearfil SE Bond, acid etching plus Clearfil SE Bond, and Prompt-L-Pop). All cavities were restored in a posterior resin composite and subjected to 200 thermocycles (at 5 degrees C to 55 degrees C; 30-second dwell time). After immersion in 0.5% basic fuchsin dye for 24 hours, the teeth were sectioned longitudinally and evaluated for dye penetration using a binocular stereomicroscope. RESULTS: There was no statistically significant differences among bonding systems in the degree of microleakage in the occlusal walls. For gingival walls, statistically significant differences were found only between the Clearfil SE Bond and Prompt-L-Pop groups and the Clearfil SE Bond with acid etching and Prompt-L-Pop groups. The greatest microleakage was observed in Prompt-L-Pop specimens. CONCLUSION: Most of the tested dentin bonding systems were able to eliminate microleakage completely in the occlusal walls, but some systems exhibited statistically significant differences in leakage in the gingival walls.     

5种牙本质黏结剂对人牙周膜细胞毒性的比较

目的：比较5种牙本质黏结剂对人牙周膜细胞的毒性作用。方法：原代培养人牙周膜细胞,采用四甲基偶氮唑盐比色法(MTT)和浸提液法,观察5种牙本质黏结剂(Super Bond C&B、Clearfil SE Bond、G-Bond、Single Bond2、Adper Easy One)不同体积分数浸提液(100%、50%、25%)作用不同时间(24 h、48 h、72 h)对人牙周膜细胞的毒性作用。采用SPSS19.0软件包对数据进行统计学分析。结果：5种牙本质黏结剂对人牙周膜细胞的细胞毒性Super BondP<0.05),48 h与72 h无显著差异(P>0.05)。结论：5种牙本质黏结剂细胞毒性程度不同,Super Bond C&B、G-Bond和Clearfil SE Bond的细胞毒性均较轻微,Single Bond2的细胞毒性较强。     

Effective bond strength of current adhesive systems on deciduous and permanent dentin

PURPOSE: To evaluate the bond strength of a total-etching, self-priming system (Single Bond) and a self-etching system (Clearfil SE Bond) to deciduous and permanent human dentin. METHODS AND MATERIALS: Buccal dentin discs were prepared with a diamond disc from permanent first premolars, permanent third molars and deciduous second molars. The flat dentin surfaces were obtained by polishing with wet 600 grit silicon carbide papers. The specimens of each group were further divided into two groups for bonding to either Single Bond or Clearfil SE Bond. After 24 hours, the microshear bond strength testing was executed on a universal testing machine. Statistical analysis was performed at alpha = 0.05. RESULTS: No significant differences in bond strength were found between materials. However, deciduous dentin demonstrated significantly lower bond strengths than permanent premolar dentin when Single Bond was applied (p < 0.05). CONCLUSION: The difference in bonding substrate (permanent or deciduous dentin) had a significant effect on bond strength when the total-etching, self-priming system was applied.     

纵折牙口外粘接再植后行全冠修复的远期临床效果分析

目的回顾性分析和跟踪随访纵折牙的临床资料,评价纵折牙口外粘接后再植的临床效果。方法收集89颗纵折牙,其中牙髓治疗后的患牙占75例（占84.23%）,口外完善根管治疗后,采用Super Bond C＆B粘接剂粘接后,植回牙槽窝,再植术后2个月全冠修复,通过12个月、18个月、24个月及36个月患牙的牙龈指数（GI）、牙周情况、松动度、X线摄片等方面进行监测,评估临床效果。对每期的成功率进行统计学分析。结果随访12个月、18个月、24个月和36个月的成功率分别为80.90%、65.17%、51.69%和35.96%。36个月时仅有32颗患牙能恢复良好的咀嚼功能,无明显松动度,无叩痛,根尖和根分叉处骨质正常,无牙周袋。结论纵折牙口外粘接再植后3年疗效不佳,患牙的牙折裂时间、患者年龄、全身状况、牙位、咬合力及口腔卫生状况可能会影响其成功率。     

Correlation among dentin depth, permeability, and bond strength of adhesive resins

Correlations among dentin permeability, dentin depth, and dentin bonding of Scotchbond, Clearfil New Bond, and Superbond C&B were studied in bovine incisor crown segments. Since the dentin surface was prepared on deeper dentin, the permeability of the dentin increased both in the presence of, and especially after removal of, the smear layer. In general, the deeper the dentin, the lower the bond strengths of Scotchbond, Clearfil New Bond, and Superbond C&B. The higher the dentin permeability, the lower the bond strength of Superbond C&B, but there was no simple relationship in the case of either Scotchbond or Clearfil New Bond. The bond strength of Superbond C&B was much higher than those of Scotchbond or Clearfil New Bond at any depth of dentin. Superbond C&B should be considered as both an enamel- and dentin-bonding agent.     

Effect of bonding systems on post-operative sensitivity from posterior composites

PURPOSE: To compare post-operative sensitivity from posterior composites lined with bonding systems that utilize either a self-etching primer or phosphoric acid conditioner. METHODS: Occlusal cavities on homologous contralateral posterior teeth in 28 selected subjects were lined with either One-Step Plus (a bonding system that utilizes phosphoric acid conditioner) or Clearfil SE Bond with a self-etching primer, and then restored with a hybrid resin composite. Post-operative sensitivity was assessed subjectively by asking the patient to classify pain from the restored tooth into none, mild or severe; and objectively by measuring the time it took for the patient to feel cold sensation when standardized ice stick was placed against the mid-buccal surface of the tooth. RESULTS: Subjective assessment showed that post-operative sensitivity was mild with either of the bonding systems; and marginal homogeneity test showed no statistically significant difference in the prevalence of post-operative sensitivity (P> 0.05), although there was a trend towards decreasing sensitivity with Clearfil SE Bond as post-operative period increased (P= 0.027). In the objective assessment, repeated measures of ANOVA showed that cold response measurements increased significantly with postoperative period only in the teeth lined with Clearfil SE Bond (P< 0.05), indicating decreasing post-operative sensitivity. However, paired t-test showed no significant difference between the cold response measurements obtained for the two bonding systems (P> 0.05).     

Bond angle effects on microtensile bonds: laboratory and FEA comparison.

OBJECTIVE: To test the hypothesis that there is a reduction in bond strength when a microtensile load is applied to adhesive junctions prepared at 10, 20 and 30 degrees to the usual perpendicular interface. To evaluate the effect of bond angle and adhesive layer thickness on stress levels within the adhesive joint utilizing FEA. METHODS: Twenty-four non-carious third molars were selected, occlusal enamel removed and polished perpendicular to the long axis of the tooth. The Clearfil SE Bond and Single Bond were applied on the dentin. A 4 mm resin restoration, Z 100, was built up. The teeth were sectioned at 10 degrees, 20 degrees and 30 degrees to the bonding interface (n = 3). The control (n = 3) group had all cuts parallel to the tooth longitudinal axis (0 degrees bond angle). The bond values were calculated in MPa and Two-Way ANOVA and Tukey test applied. FEA was performed (1 mm/side square specimens) to obtain the maximum principal stress (MPS) in the microtensile-model for each bond angle and for varying adhesive thickness from 20 microm to 200 microm for each group. RESULTS: The bond strength results diminish as the angle on the interface increased (P<0.05) for Clearfil SE Bond between 0 (control) and 30 degrees, and for Single Bond between 0 (control) and 10, 20, and 30 degrees. The hypothesis can be fully accepted for Single Bond and partially accepted for Clearfil SE Bond. For the FEA, there was a trend toward decreasing MPS as the bond angle increased, while the MPS for each angled group increased with adhesive layer thickness. SIGNIFICANCE: The MPS results for angled interfaces, exhibited the same trend as the lab values. FEA results indicated an MPS increase with increased adhesive thickness.     

Shear bond strengths of tooth fragments reattached or restored

This study investigated the shear bond strengths of sectioned human mandibular incisor edge fragments reattached using luting cements, bonding agents or restored with composite resins. Seventy teeth were randomly distributed among six experimental groups and a control group. Leaving half of the anatomic crowns exposed, the teeth were embedded in self-cure acrylic resins with the exposed part then sectioned. The fragments in groups 1-4 were bonded to their respective teeth using Clearfil Liner Bond 2V, Scotch Bond Multi Purpose Plus, Panavia-F and 3M Opal Luting cement. The 5th and 6th groups were restored with composite resins (Silux 3M and Clearfil AP-X) using their bonding agents (Single Bond and Clearfil SE Bond). The results indicated that reattachment of fractured incisal fragments by using new generation bonding agents was effective against shear stresses, comparable with the intact teeth. Instead of restoration with composite resins therefore reattachment of a fractured fragment might be more preferable in cases of dental trauma.