切牙切角缺损大小对其贴面修复后抗折性能的影响

The effect of the size of incisor angle defects on the ?exural performance of the veneer after repair

目的研究切牙切角缺损大小对其贴面修复后抗折性能的影响。方法收集离体上颌中切牙42颗,随机均分为6组(1A、2A、3A、1B、2B、3B组),每组7颗,其中1、2、3代表缺损等级,A、B分别代表IPS e.max铸瓷贴面和GC硬质树脂贴面。每组按不同缺损大小预备牙体,并在唇侧缺损边缘制备宽1 mm,深度为0.5 mm浅凹形微创边缘。然后分别按照标准工艺程序完成微创IPS e.max Press铸瓷贴面和GC.GRADIA硬质树脂贴面。各组均用3M RelyX Veneer树脂粘接套装粘固于离体牙上,用万能测力机测试抗折力,体视显微镜观察断裂模式。结果微创铸瓷贴面修复的抗折力与缺损大小有关。1A组与2A、3A组之间差异有统计学意义(P<0.05),2A组与3A组差异无统计学意义(P>0.05),微创瓷贴面复合体主要的破坏模式为粘接面脱落(占71.43%);微创树脂贴面修复的抗折力与缺损大小无明显关系,3组间抗折力差异无统计学意义(P>0.05),微创树脂贴面复合体的破坏模式为树脂贴面崩折(100%)。抗折力2A组>2B组、3A组>3B组,其差异都有统计学意义(P<0.05)。结论在本实验条件下,缺损等级越大,微创铸瓷贴面修复后抗折力越大;而缺损等级大小对微创树脂贴面修复抗折力影响较小,在2、3级缺损时微创瓷贴面的抗折力都大于微创树脂贴面,提示当前牙咬力较大,缺损等级增大时,应尽可能选择抗折力较大的微创瓷贴面修复。

Objective To compare the flexural strength of maxillary middle incisors repaired by minimally invasive veneer with different defect sizes and repair materials.Methods 42 extracted human maxillary central incisors were divided into 6 groups(group 1A,2A,3A,1B,2B,3B)(N=7 for each group),Defects were defined as grade 1,2,or 3 according to the defect involving 1,2,3 regions.A and B respresent IPS e-max porcelain veneer and GC resin veneer,respectively.Grade 1,2,and 3 defects were made for group 1A and 1B,2A and 2B,and 3A and 3B,respectively.Overall the preparations were 1 mm in width and 0.5 mm in depth with a chamfer margin in each group.Minimally invasive e-max porcelain veneer restorations and minimally invasive resin veneer restorations were completed in the mechanic center.The universal testing machine was used to measure the flexural strength after restoration and bonding with resin cement(Rely-X Veneer),and failure modes was observed under a stereomicroscope.Data was analyzed using the SPSS16.0 software.Groups were compared using the one-way ANOVA.Results The size of defects affects the flexural strength of minimally invasive porcelain veneers complex.Mean(SD)flexural strength of minimally invasive porcelain veneers complex was:grade 1A defect had a significantly lower flexural strength than grade 2A defect and grade 3A defect(P<0.05),and there was not significant difference in flexural strength between grade 2A defect and grade 3A defect(P >0.05).The main failure mode was adhesive failure(71.43%).The size of defects had no significant effect on the flexural strength of minimally invasive resin veneers complex.Failure mode was fracture of the resin material in GC resin veneer group.The flexural strength was not significantly different between group 1A and 1B.In grade 2 and 3 defects,flexural strength of minimally invasive porcelain veneer complex(2A,3A)was significantly higher than that of resin veneer complex(2B,3B)(P<0.05).Conclusions Under this experimental condition,the higher the defect level was,the greater the flexural strength of repaired minimally invasive casting porcelain was.However,the defect grade had little impact on the flexural strength of minimally invasive resin veneer.The flexural strength of the minimally invasive ceramic veneer was greater than that of the minimally invasive resin veneer in grade 2 and grade 3 defects,indicating that when occlusal force and defect grade was large,minimally invasive ceramic veneer repair with large folding strength should be selected as far as possible.