三种粘接剂粘接不同牙本质的微拉伸粘接强度比较

目的采用微拉伸粘接强度实验测定3种牙本质粘接剂粘接楔状缺损处硬化牙本质的粘接强度。方法选择有典型楔状缺损并因牙周病拔除的上颌前磨牙30颗作为实验组，正常上颌前磨牙30颗作为对照组，使用粘接剂A（全酸蚀粘接剂Scotchbond Multi—Purpose）、B（一步法自酸蚀粘接剂Adper Prompt L-Pop）和C（两步法自酸蚀粘接剂Contax）处理硬化牙本质和正常牙本质表面，相应树脂修复。测试两组试件的微拉伸粘接强度。结果粘接剂A、B、C粘接硬化牙本质的微拉伸粘接强度分别为46．805MPa、39．045MPa、29．852MPa。粘接剂A和C与硬化牙本质的微拉伸粘接强度低于正常牙本质，而粘接剂B与之相反，差异有统计学意义（P〈0．05）。结论牙颈部楔状缺损处硬化牙本质由于结构上的特殊性可造成粘接困难。酸性强有利于粘接剂与硬化牙本质的粘接。     

脱矿牙本质与四种粘接剂的粘接强度测试及粘接界面观察

目的比较脱矿牙本质与4种全酸蚀或自酸蚀粘接剂的粘接强度及粘接界面超微结构的差异,以期对临床治疗有所指导。方法选择20颗面龋坏的离体磨牙,在龋显示剂的指示下去除牙本质龋的感染层,保留脱矿牙本质。平齐龋洞洞底平面,去除冠向牙体组织,作为粘接面。选择临床常用的2种全酸蚀粘接剂:材料A(All Bond2)、材料B(Prime&BondNT)和2种自酸蚀粘接剂:材料C(ClearfilSEBond)、材料D(XenoⅢ),分别按说明书要求粘接。用慢速锯将样本牙切为粘接面积约0.9mm×0.9mm的长方体试件。体视显微镜下将试件分为正常牙本质组和脱矿牙本质组,用微拉伸测试仪检测粘接强度。扫描电镜观察各组试件粘接界面的超微形态。结果方差分析提示牙本质类型和粘接剂对微拉伸粘接强度的影响均有统计学意义(P<0.05)。对正常牙本质,不同粘接剂的微拉伸粘接强度差异无统计学意义(P>0.05);对于脱矿牙本质,材料D的微拉伸粘接强度较其他粘接剂明显降低(P<0.05)。扫描电镜下观察脱矿牙本质的混合层多孔稀疏,树脂突短少,无侧枝形成。结论对脱矿牙本质,本项实验中全酸蚀粘接剂的粘接强度优于自酸蚀粘接剂。     

一步法自酸蚀粘接剂微拉伸粘接强度的研究

目的评价一步法白酸蚀粘接剂的牙本质微拉伸粘接强度，观察并分析样本断裂类型。方法选择新拔除的人无龋下颌第三磨牙12颗，分别用3种一步法、1种两步法的白酸蚀粘接剂进行牙本质粘接。用微拉伸测力仪测试粘接强度，并用体视显微镜和扫描电镜观察样本断裂类型。结果3种一步法白酸蚀粘接剂的微拉伸强度分别为：材料A（Adper Prompt）（23．36±2．55）MPa；材料B（Clearfil S^3 Bond）（30．46±3．82）MPa；材料C（Xenon Ⅲ）（34．59±3．46）MPa；1种两步法自酸蚀粘接剂材料D（Clearfil SE Bond）的微拉伸粘接强度为（45．06±5．29）MPa。材料D微拉伸粘接强度最高，与其他3组相比，差异具有统计学意义（P〈0．01）。样本断裂均发生于粘接界面，未观察到复合树脂或牙本质内聚破坏。结论一步法白酸蚀粘接剂的牙本质粘接强度低于两步法白酸蚀粘接剂，但多数仍可满足临床对树脂粘接强度的要求。     

氯已定预处理对两步法自酸蚀粘接剂牙本质粘接界面稳定性的影响

目的：探讨氯已定预处理对两步法自酸蚀粘接剂的牙本质粘接界面稳定性的影响.方法：40颗离体人磨牙沿垂直于牙长轴的方向切割,暴露冠中部牙本质作为粘接面,牙本质试件随机分为两组,一组在粘接处理前涂布0.2％氯已定为实验组,一组无预处理为对照组,两组经两步法自酸蚀粘接剂SE Bond处理后,堆积复合树脂制备成粘接试件.每组随机抽取2个试件借助微拉曼光谱仪分析粘接剂的双键转化率,剩余的18个试件随机分为两个亚组,分别于即刻和冷热循环5000次后检测微拉伸粘接强度和界面的纳米渗漏情况.结果：0.2％氯已定预处理对SE Bond的树脂双键转化率无显著性影响（P＞0.05）.即刻测试时,对照组和实验组间的微拉伸粘接强度和纳米渗漏差异无统计学意义（PP ＞0.05）.冷热循环老化处理后,实验组的微拉伸粘接强度显著高于对照组,纳米渗漏程度显著低于对照组（P＜0.05）.结论：0.2％氯已定预处理不会干扰SE Bond的树脂聚合,且可提高其与牙本质粘接界面的稳定性.     

脱敏剂对牙本质粘接剂剪切粘接强度的影响

目的 研究脱敏剂对牙本质粘接剂剪切粘接强度的影响,以期为临床操作提供参考.方法 将20个牙试件均分为实验组和对照组,每组10个;实验组牙本质表面涂布脱敏剂(极固宁TM);对照组不做任何处理.用牙本质粘接剂(Variolink Ⅱ)将铸瓷(IPS Empress)粘接于两组试件牙本质粘接面上,测试剪切粘接强度,扫描电镜(SEM)观察试件断面.结果 实验组和对照组的剪切粘接强度分别为(5.53±0.96)MPa和(7.32±1.34)MPa,差异有统计学意义(P=0.003).SEM见实验组试件发生黏附破坏,对照组试件发生内聚破坏.结论 牙本质表面涂布脱敏剂后可显著降低粘接剂的剪切粘接强度.     

乙醇润湿对2种全酸蚀粘接剂粘接性能的影响

目的:探究牙本质粘接前用乙醇润湿对临床常用2种全酸蚀粘接剂粘接强度和粘接界面质量的影响。方法:24颗新鲜拔除人无龋磨牙随机分为6组,2种粘接剂Single Bond(SB)、Gluma Comfort Bond(GB),每种分成3组用不同方法粘接即:对照组(粘结剂常规应用组)、乙醇润湿1min组、乙醇润湿2min组。每组牙制作微拉伸试件,测试24h微拉伸粘接强度(MTBS),用体视显微镜观察断面类型。用扫描电镜观察粘接界面混合层和树脂突形态。结果:乙醇润湿2min的方法使以上两种粘接剂的24h瞬时微拉伸强度(MTBS)显著提高;而乙醇浸润1min的效果与对照组无统计学差异。SEM观察结果也提示乙醇润湿2min能够显著改善粘接界面混合层的质量、增加树脂突的数量以及长度;乙醇1min可以增加树脂突长度,但对数量无明显影响。结论:乙醇润湿2min对2种粘接剂的粘接性能有显著改善。     

Nd:YAG激光增加非龋性硬化牙本质全酸蚀粘接强度的实验研究

目的 通过微拉伸粘接强度实验,探讨激光对全酸蚀粘接剂处理后的非龋性硬化牙本质与复合树脂粘接强度的影响.方法 选择牙本质视觉分级为3级以上的(牙合)面磨损后牙10颗,每颗牙以低速锯垂直于牙本质表面,将硬化牙本质分为面积相等的两部分(约12 mm2),按随机数字表法将这两部分分为实验组和对照组,实验组经Nd∶YAG激光(1 W,10 Hz)处理后,使用Scotchbond (STB)酸蚀、涂布粘接剂Adper Single bond 2(ASB)联合Z350复合树脂充填,对照组使用STB酸蚀、涂布粘接剂ASB联合Z350复合树脂充填.置于37 ℃生理盐水中24 h后,制作微拉伸试件并测试微拉伸粘接强度,体视显微镜下观察断裂模式并分类.采用SPSS13.0软件对微拉伸粘接强度值做t检验.结果 实验组粘接强度[(26.11±1. 62)Mpa]显著高于对照组[(22.27±2.16)Mpa],差异有统计学意义(P=0.006).体视显微镜下可见断裂多发生于牙本质-树脂粘接面.结论 Nd∶YAG激光能够提高硬化牙本质与全酸蚀粘接系统的粘接强度.     

丙酮基和酒精-水基牙本质粘接系统粘接强度比较及粘接界面观察

目的:比较丙酮基和酒精-水基两种不同溶剂类型的全酸蚀牙本质粘接系统粘接强度和粘接界面的微观形态。方法:选择24颗正畸治疗拔除的健康前磨牙,去除合面釉质层,随机分两组,每组选用一种 “两步法”全酸蚀牙本质粘接系统:以丙酮为溶剂的Prime & Bond NT(PB组)和以酒精和水为溶剂的Single Bond 2(SB2)组,粘接后进行微拉伸力检测。以扫描电镜(SEM)和激光共聚焦扫描电镜(LCSM)观察两种牙本质粘接系统的粘接界面。结果:粘接强度PB组(29.49±4.01) MPa,SB2组微拉伸粘接强度为,SB2组为(30.03±4.33) MPa,无统计学差异。两种牙本质粘接系统均可充分渗入脱矿牙本质表层的胶原纤维网和牙本质小管内,形成混合层和树脂突,SB组混合层薄而均匀,树脂突长。结论:不同溶剂类型的两组牙本质粘接系统微拉伸粘接强度无差异,全酸蚀牙本质粘接系统在湿粘接状态下可以对牙本质形成良好的渗透。     

超声处理对牙本质玷污层性状及粘接强度的影响

目的 探究超声处理对牙本质表面玷污层性状及其对通用型树脂粘接剂自酸蚀模式下粘接强度的影响。方法 将40颗人无龋下颌第三磨牙随机分为320目碳化硅砂纸打磨组以及砂纸打磨加超声处理组,运用扫描电子显微镜观察牙本质表面玷污层性状;处理后的牙体分别用Rhodamine B染色的2种通用型树脂粘接剂(Clearfil Universal Bond和All-Bond Universal, pH值分别为2.3和3.1)粘接复合树脂,观察粘接界面的渗透情况;最后制作微拉伸试件进行微拉伸强度测试。结果 扫描电子显微镜显示,超声处理能够使大量牙本质小管暴露;激光扫描共聚焦显微镜显示超声处理过后2种粘接剂都能沿牙本质小管渗透入牙本质深部;微拉伸强度测试结果表明超声处理能够增强2种通用型树脂粘接剂自酸蚀模式下的粘接强度;但在相同的牙本质表面处理条件下,这两种粘接剂间的粘接强度差异无统计学意义。结论 超声处理能够部分去除牙本质表面玷污层,暴露牙本质小管,增加通用型树脂粘接剂自酸蚀模式下的粘接强度。     

4种粘接剂对牙本质粘接强度的体外评价

目的比较4种粘接剂对牙本质的粘接强度,并观察粘接界面,评估其抗力性能。方法采用Prime & BondNT（PBNT）、Tetric N-Bond（TNB）、Clearfil SE Bond（CSEB）、G Bond（GB）4种粘接剂粘接树脂于离体下颌第三磨牙的咬合面和近中面,近中面进行剪切力实验,记录断裂峰值;咬合面部分进行微拉伸粘接强度（TBS）测定,扫描电镜观察粘接界面形态。结果在剪切力实验中,PBNT与TNB的抗剪切粘接强度（SBS）最大,两者间差异无统计学意义（P>0.05）。PBNT的SBS高于CSEB与GB（P<0.05）;TNB的SBS高于GB（P<0.05）,与CSEB的强度差异无统计学意义（P>0.05）。与剪切力实验结果一致,PBNT和TNB的TBS高于CSEB和GB（P<0.05）。扫描电镜下,PBNT和TNB的树脂突比较细长,粘接层较厚;CSEB树脂突短小,GB树脂突更加稀疏。结论全酸蚀粘接剂的粘接强度较自酸蚀粘接剂高,一步法自酸蚀粘接剂强度最低;粘接剂的界面形态与粘接强度存在一定程度的关联性。     

简化乙醇湿粘结对龋影响牙本质粘结强度的影响

目的:评估简化乙醇湿粘结技术对龋影响牙本质粘结强度的影响。方法:选取人慢性龋离体第三磨牙36颗去龋备洞后保留龋影响牙本质。随机分为6组,分别使用自制疏水性粘结剂,Prime & Bond NT(PB),Adper Single bond plus(SB)进行粘结,堆砌树脂厚度约4~5 mm。实验组采用简化乙醇湿粘结法,对照组采用传统水湿粘结法。制作1 mm ×1 mm ×8 mm的条形微拉伸强度试件,每组选取8个。采用万能材料试验机测试微拉伸强度并记录,观察断裂界面。结果:在自制疏水性粘结剂组中,实验组粘结强度较对照组有显著提高(P<0.05)。结论:简化乙醇湿粘结技术可以提高CAD界面的粘结强度,尤其是在与疏水性粘结剂联合运用时,有显著提高。     

复合树脂联合两种酸蚀粘结剂与乳牙釉质及牙本质的剪切粘结强度比较

目的:比较复合树脂联合全酸蚀和自酸蚀粘结剂与乳牙釉质及牙本质的剪切粘结强度。方法:收集新鲜拔除的滞留乳磨牙48个,随机分为4组,分别制备全酸蚀和自酸蚀粘结剂的釉质和牙本质试件,电子万能试验机测定各组剪切强度;体视显微镜下观察试件断面的破坏模式;扫描电镜观察粘结界面情况。结果:全酸蚀粘结剂组的釉质剪切强度明显高于牙本质剪切强度(P<0.05);自酸蚀粘结剂组釉质与牙本质剪切粘结强度无统计学差异(P>0.05);全酸蚀粘结剂组的釉质、牙本质剪切粘结强度均明显高于自酸蚀粘结剂组(P<0.05);体视显微镜及扫描电镜观察均显示,全酸蚀粘结剂与釉质和牙本质的粘结界面结合程度好于自酸蚀粘结剂。结论:全酸蚀粘结剂处理对乳牙釉质及牙本质的剪切粘结强度高于自酸蚀粘结剂。     

10-MDP-钙盐形成对牙本质粘接成绩影响的评价

目的 分析10-MDP-钙盐形成对牙本质粘接成绩的影响.方法 采用酸蚀冲洗粘接模式,根据牙本质表面的处理方式和选择粘接剂的不同将牙齿随机分为以下4组(n=5)进行处理,制作牙本质/树脂粘接试件:①对照组,直接使用全酸蚀粘接剂Single bond 2(SB2)处理后粘接;②10-MDP组,使用SB2处理进行粘接前,牙本...     

粘结剂使用方式对全酸蚀树脂水门汀与牙本质粘结性能影响的研究

目的评价粘结剂的3种不同使用方式（不使用粘结剂,粘结剂不固化及粘结剂固化10 s）对全酸蚀树脂水门汀与牙本质间粘结性能的影响。方法新鲜拔除的无龋人第三磨牙45颗,随机分为9组（n=5）,流水降温下磨除冠部牙釉质,制备标准牙本质粘结面,酸蚀冲洗后表面按全酸蚀粘结技术处理,牙本质粘结剂处理方式按设计进行,然后与3种全酸蚀树脂水门汀（Rely X ARC、Calibra、VariolinkⅡ）粘结并测试微拉伸粘结强度,用扫描电镜观察粘结界面。结果对于3种全酸蚀树脂水门汀,不使用粘结剂组未测得粘结强度;粘结剂不固化组及粘结剂固化10 s组均获得较为满意的粘结强度,不固化组的微拉伸粘结强度（15.534±2.099;22.827±6.968;10.736±3.199）显著高于粘结剂固化10 s组（13.476±2.710;14.076±5.165;7.736±3.052）（P〈0.05）。结论①全酸蚀树脂水门汀应结合粘结剂同时使用。②牙本质涂布粘结剂后不单独固化可显著提高全酸蚀树脂水门汀与牙本质的粘结强度。     

The effect of several dentin desensitizers on shear bond strength of adhesive resin luting cement using self-etching primer

Objectives

Dentin desensitizers can inhibit the bonding between dentin and resin cements. This study examined the effect of the previous application of desensitizers on the shear bond strength of one resin cement using self-etching primer to dentin.

Materials and methods

One hundred and twenty-five dentin exposed teeth were randomly assigned to four experimental groups and one control group of 25 teeth each. Four dentin desensitizers were applied to the four experimental groups, respectively. The dentin desensitizers used were SuperSeal^® (Phoenix Dental, Inc., USA), MS-Coat^® (Sun Medical Co. Ltd, Japan), Gluma^® (Heraeus Kulzer, Germany), and Copalite Varnish^® (Cooley &; Cooley Ltd, USA). Panavia F (Kuraray Co. Ltd, Tokyo, Japan) was attached to the top of each experimental and control group teeth using an Ultradent testing jig (Ultradent Product, Inc., Utah, USA), and the shear bond strength was measured using a Universal testing machine (Model 6022, Instron Co., Canton, MA, USA). The tooth surface was examined by scanning electron microscopy (SEM, JSM-T2000, JEOL, Tokyo, Japan).

Results

The control group showed the greatest shear bond strength (14.74 MPa) followed by SuperSeal^® (12.33 MPa), Gluma^® (5.28 MPa), MS-Coat^® (4.44 MPa) and Copalite Varnish™ (3.14 MPa). There was no significant difference in shear bond strength between the control group and the experimental group treated with Superseal^®. The shear bond strength in the other experimental groups treated with Gluma^®, Varnish^®, and MS-Coat^® was similar to each other but significantly lower than control or Superseal^®. SEM showed revealed resin tags in most of the dentinal tubules in the experimental group treated with the Superseal^®.

Conclusion

Among the four dentin desensitizers, Superseal^® was the only one that did not interfere with the process of resin bonding. The other dentin desensitizers that contained a resin ingredient interfered with resin retention.     

Dentin conditioned with a metal salt-based conditioner

ObjectivesUniversal adhesives (UAs) can optionally be applied in either an etch-and-rinse (E&R) or self-etch (SE) bonding mode. As the preferred bonding mode differs for enamel versus dentin, a universal conditioner for both enamel and dentin in replacement of the relatively aggressive phosphoric-acid etchant remains desirable. This study aimed to test if a metal salt-based etchant (ZrO(NO₃)₂) provides as durable bonding to dentin as a classic E&R or SE bonding modeMethodsBefore applying the UA Adhese Universal (‘AdU’; Ivoclar Vivadent) to bur-cut dentin of 24 teeth (n = 8), dentin was conditioned with either (1) an experimental metal salt-based conditioner (‘ZON’; Ivoclar Vivadent) or (2) 37% phosphoric acid (Total Etch gel, Ivoclar Vivadent), representing a classic ‘E&R′ mode; (3) a third experimental group involved AdU applied in SE mode. Bonding effectiveness was determined in terms of immediate (‘1w’) and aged (‘50k’ TC) micro-tensile bond strength (μTBS) to bur-cut dentin. Adhesive-conditioned dentin interfacial interactions were characterized by S/TEM.ResultsLinear mixed-effects modeling revealed significantly higher immediate μTBS to dentin of ZON_AdU than E&R_AdU, while ZON_AdU performed not significantly different from SE_AdU. No significant differences were found between the three experimental groups after 50k TC (aged μTBS). S/TEM disclosed less exposure of dentinal collagen fibrils when AdU was bonded upon ZON etching than when applied in E&R mode. Moreover, ZON resulted in more hydroxyapatite (HAp) crystals remaining at the bottom of the hybrid layer, while dentinal tubule orifices remained nearly fully closed, by which hardly any resin tags were formed.SignificanceThe alternative metal salt-based conditioner revealed at dentin a more HAp-protected hybrid layer with less exposure of collagen fibrils, while a comparable bond strength was obtained to that with a phosphoric-acid E&R as well as with an SE (no conditioner) bonding mode. These findings confirm that the metal salt-based conditioner can be considered as a suitable alternative (enamel/)dentin conditioner to classic phosphoric acid employed in an E&R bonding mode.     

自酸蚀树脂水门汀ResiCem牙本质粘结强度的评价

目的 评价自酸蚀树脂水门汀ResiCem的牙本质粘结强度并探讨酸蚀对其粘结强度的影响。方法 选择离体无龋第三恒磨牙15颗。沿垂直于牙体长轴方向将磨牙冠中1/3处切开,将牙本质面分别用自酸蚀树脂水门汀Panavia F和Resi-Cem原位对位粘结。其中ResiCem组牙本质面分别用磷酸酸蚀0、5、10、15 s。用低速切片机把样本切割成约1 mm×1 mm×8mm条块后进行微拉伸测试,并通过扫描电镜观察粘结界面。结果 ResiCem的牙本质微拉伸粘结强度[(16.9±5.3)MPa]与Panavia F[(17.0±5.2)MPa]间差异无统计学意义(P>0.05)。磷酸酸蚀显著地降低ResiCem与牙本质间的粘结强度(P<0.05),并随着酸蚀时间的延长而降低。结论 ResiCem的牙本质微拉伸粘结强度与Panavia F相当,但酸蚀会降低ResiCem的牙本质粘结强度。     

Using bonding agent prior to pits and fissure sealant application enhances the microtensile bond strength and the interface morphology

BackgroundA pits and fissures sealant is an effective method for preventing dental caries. Using a bonding agent before applying the sealant may increase its retention. This study aimed to compare the microtensile strength (µTBS) of a fissure sealant with and without a bonding agent and to characterize the enamel-sealant interface using confocal laser scanning microscopy (CLSM). The null hypothesis was that the use of a bonding agent before fissure sealant application would not change the microtensile strength or the enamel-sealant interface.Materials and methodsTwenty caries-free premolars were used. Each tooth was divided into four parts. The first two parts were assigned to the bonded group, where a bonding system was used before sealant application. The remaining two parts were treated only with a fissure sealant (i.e., the nonbonded group). In each group, the µTBS was examined after 24 h (n = 20) and after a 3-month aging period (n = 20). Five other caries-free extracted premolars were used to assess the enamel-sealant interface using CLSM. Two-way analysis of variance (ANOVA) and Pearson chi-square statistical analysis tests were used to analyze the µTBS and the enamel-sealant interface, respectively.ResultsThe mean µTBS for the bonded group was significantly higher (p = 0.001) in the immediate group (36.87 ± 14.95 MPa) and the aged group (31.08 ± 15.88 MPa) than in the respective nonbonded groups (19.77 ± 9.67 MPa and 19.52 ± 14.14 MPa). The µTBS was not significantly different in either group after aging (p = 0.46 [bonded group] and p = 0.98 [nonbonded group]). In addition, using a dental adhesive, before applying a fissure sealant resulted in a significantly higher (53%) resin penetration into the enamel with the continuous integrity of the resin.ConclusionThe use of a bonding agent before the application of fissure sealant resulted in superior microtensile bond strength immediately and after aging. In addition, the enamel-sealant interface characteristics were improved.     

NaClO溶液的浓度和作用时间对树脂牙本质粘结界面的影响

目的:研究次氯酸钠(NaClO)溶液的浓度和作用时间对树脂牙本质粘结界面的影响.方法:选取50颗离体磨牙,去除牙齿根部及牙合面釉质,暴露牙本质层并堆塑4 mm厚的复合树脂块.分别沿两个垂直方向纵向片切样本,制备横截面积为1.0 mm2的试件条.选取50个试件随机分为5组:A1组(2.5％NaClO溶液浸泡1 h)、A2...     

Treatment of crown fractured incisors with laminate veneer restorations. An experimental study

Abstract A method is described by which crown fractured incisors are restored with cast ceramic (Dicor) laminate veneers after initial treatment with either reattachment of the original crown fragment with a dentin bonding agent, with a composite resin build-up or no treatment (i.e. the veneer alone is used to restore the incisal edge). In order to elucidate the effect of the fragment/composite-tooth bonding interface on fracture strength of the restored teeth, the fracture strengths of the various treatment groups were compared to that of intact teeth supplied with Dicor laminate veneers. In an experimental investigation using central and lateral incisors from sheep, it was found that fracture strength (16.6 ±4.2 MPa) equal to that of intact incisors (16.1 ± 2.6 MPa) could be achieved using laminate veneers made of porcelain on fractured teeth whose crown fragments were reattached using a dentin bonding agent (5). In the present investigation, using the same experimental model but using cast ceramic (Dicor) laminate veneers, the fracture strength of the restored incisors was significantly increased (21.0 ± 3.7 MPa), exceeding that of intact teeth. The fracture strength of intact teeth was also exceeded in veneered incisors which were initially restored with a conventional composite resin build-up (20.2±5.6 MPa). However, the greatest fracture strength (28.2 ±8.9 MPa) was achieved when a Dicor laminate veneer alone was used to restore the fractured ineisal edge. The strength was equivalent to that of intact teeth supplied with Dicor veneers (26.7 ± 6.3 MPa). While fracture strengths of teeth which were initially restored by fragment reattachment and then supplied with veneers exceeded that of intact teeth when veneer preparation was limited to enamel, they were reduced to the half of (hat of intact teeth (i.e. the same strength as teeth initially restored by fragment reattachment and no veneering) if the preparation extended into dentin. In the present experimental model, ii would appear that laminate veneers alone might be used to restore lost incisal edges of crown fractured anterior teeth.