模拟牙冠延长术联合牙本质肩领设计对斜折残根抗折力的影响  

Effect of different ferrule lengths on the fracture resistance of endodontically treated mandibular premolars restored with prefabricated fiber post-and-core system after simulated crown lengthening

作　　者：孟庆飞 张甲第 孟箭 Meng Qingfei;Zhang Jiadi;Meng Jian(Department of Stomatology,Affiliated Xuzhou Hospital,College of Medicine,Southeast University,Xuzhou 221009,China)

机构地区：[1]东南大学医学院附属徐州医院口腔科,徐州221009

出　　处：《中华口腔医学研究杂志（电子版）》2018年第1期26-30,共5页Chinese Journal of Stomatological Research(Electronic Edition)

基　　金：徐州市医学青年后备人才(徐卫科教[2015]7号);江苏省青年医学重点人才(QNRC2016391)

摘　　要：目的研究模拟牙冠延长术联合不同高度牙本质肩领设计,对预成纤维桩核修复后的下颌第一前磨牙斜折残根抗折力的影响。方法选择24颗完整离体下颌第一前磨牙,先于舌侧釉牙骨质界上2.0 mm处截冠成为水平型冠折残根,再自残根断面舌侧向颊侧斜行切割,制备舌唇向斜折残根模型。查随机数字表,将所有残根样本平均分为3组:A组在残根颈部预备颊侧0 mm、舌侧2.0 mm高的半包绕肩领(对照组),B组和C组通过模拟牙冠延长术在残根颈部分别预备颊侧1.0、2.0 mm高的肩领,对应舌侧肩领高度分别为3.0和4.0 mm。经玻璃纤维桩核铸造金属全冠修复后,所有试样自铸造全冠颈缘完成线下2.0 mm包埋于自凝塑料块中。将试样以与牙长轴成135°放置于万能力学试验机上加载,直至试样发生折裂。记录试样断裂载荷,行单因素方差分析,对差异有显著性结果再行Tukey HSD Test分析(α=0.05)。结果 A、B、C各组试样的折裂载荷均值依次为(1.01±0.26)、(0.91±0.29)、(0.73±0.19)k N,牙本质肩领对纤维桩核冠修复后斜折残根抗力影响差异无统计学意义(F=2.588,P=0.099)。颊侧无肩领对照组的残根抗力最高,而随着根颈部肩领高度的增加,斜折残根的抗折力呈现逐渐下降的趋势。结论通过模拟牙冠延长术在下颌第一前磨牙舌唇向斜折残根颈部预备1.0~2.0 mm完整肩领时,会降低残根的抗折力。Objective The purpose of this study was to evaluate the effect of ferrule design on the fracture resistance of endodontically treated mandibular first premolars after simulated crown lengthening restored with a fiber post-and-core system.Methods Twenty-four extracted and endodontically treated mandibular first premolars were decoronated at 2.0 mm above cemento-enamel junction,and then a title surface was made from lingual to buccal side.The roots were divided randomly into three equal groups,according to a table of random numbers.The control group was incompletely prepared in the cervical root,with 0 mm buccal and 2.0 mm lingual ferrule lengths(Group A).Simulated surgical crown lengthening was used to obtain a ferrule preparation of 1.0 mm(Group B)and 2.0 mm(Group C)on the buccal side,and 3.0 mm and 4.0 mm on the lingual side,respectively.After restoration with a glass fiber post-and-core system and a cast Co-Cr alloy crown,each specimen was embedded at 2.0 mm below the crown margin in an acrylic resin block and loaded to fracture at a 135°angle to its long axis in a universal testing machine.Data were analyzed statistically using One-Way ANOVA with Tukey HSD tests,withα=0.05.Results Mean fracture loads(kN)for group A,B and C were 1.01±0.26,0.91±0.29 and 0.73±0.19,respectively.No significant difference was found for the effect of ferrule lengths(F=2.588,P=0.099).The teeth with no buccal ferrule preparation in Group A had the highest fracture resistance.In contrast,with the increase of the height of buccal ferrule,the fracture strength of the roots decreased.Conclusions For lingual-to-buccal oblique fractures,increased apical ferrule preparation after simulated surgical crown lengthening may result in decreased fracture resistance of endodontically treated mandibular first premolars.

关 键 词：牙冠伸长术 桩核技术 牙折断 牙根 残余 抗折力 牙本质肩领 

分 类 号：R783[医药卫生—口腔医学]