Loguercio Alessandro Dourado, Leski Gilmara, Sossmeier Daiana, Kraul Alexander, Oda Margereth, Patzlaff Rafael Tiago, Reis Alessandra
Department of Restorative Dentistry, Universidade Estadual de Ponta Grossa Rua Carlos Covalcanti 4748 Bloco M, Sala 64 A, Vvaranas, Ponta Grossa, 84030-900 PR, Brazil.
J Dent. 2008 Apr;36(4):249-55. doi: 10.1016/j.jdent.2008.01.001. Epub 2008 Mar 4.
The aim of this study was to compare the fracture strength of three techniques used to re-attach tooth fragments in sound and endodontically treated fractured teeth with or without fiber post placement.
Ninety human lower incisors were randomly divided into three groups of 30 teeth each. In group A teeth were not subjected to endodontic treatment; while teeth from groups B and C were endodontically treated and the pulp chamber restored with a composite resin. All teeth were fractured by an axial load applied to the buccal area in order to obtain tooth fragments. Teeth from each group were then divided into three subgroups, according to the re-attachment technique: bonded-only, buccal-chamfer and circumferential chamfer. Before the re-attachment procedures, fiber posts were placed in teeth from group C using dual cure resin luting cement (Duo-Link). All teeth (groups A-C) had the fragments re-attached using a same dual cure resin luting cement. In the bonded-only group, no additional preparation was made. After re-attachment of the fragment, teeth from groups buccal and circumferential chamfer groups had a 1.0 mm depth chamfer placed in the fracture line either on buccal surface or along the buccal and lingual surfaces, respectively. Increments of microhybid composite resin (Tetric Ceram) were used in subgroups buccal chamfer and circumferential chamfer to restore the chamfer. The specimens were loaded until fracture in the same pre-determined area. The force required to detach each fragment was recorded and the data was subjected to a three-way analysis of variance where factors Group and Re-attachment technique are independent measures and Time of fracture is a repeated measure factor (first and second) and Tukey's test (alpha=0.05).
The main factors Re-attachment technique (p=0.04) and Time of fracture (p=0.02) were statistically significant. The buccal and circumferential chamfer techniques were statistically similar (p>0.05) and superior to the bonded-only group (p<0.05). The first time of fracture was statistically superior to second time of fracture (p<0.001).
The use of fiber post is not necessary for the reinforcement of the tooth structure in re-attachment of endodontically treated teeth. When bonding a fractured fragment, the buccal or circumferential re-attachment techniques should be preferable in comparison with the simple re-attachment without any additional preparation. None of the techniques used for re-attachment restored the fracture strength of the intact teeth.
本研究旨在比较三种用于重新连接完整牙齿以及经牙髓治疗的折断牙齿碎片的技术的抗折强度，这些牙齿有无纤维桩植入。
90颗人类下颌切牙随机分为三组，每组30颗。A组牙齿未进行牙髓治疗；B组和C组牙齿进行牙髓治疗，并用复合树脂修复髓腔。所有牙齿通过向颊侧施加轴向载荷使其折断以获得牙齿碎片。然后根据重新连接技术，将每组牙齿再分为三个亚组：仅粘结、颊侧倒角和环形倒角。在重新连接操作前，使用双固化树脂粘结剂（Duo-Link）为C组牙齿植入纤维桩。所有牙齿（A - C组）均使用相同的双固化树脂粘结剂重新连接碎片。在仅粘结亚组中，未进行额外预备。碎片重新连接后，颊侧倒角组和环形倒角组的牙齿分别在颊侧表面或沿颊舌侧表面的骨折线处制备1.0mm深的倒角。颊侧倒角亚组和环形倒角亚组使用微混合复合树脂（Tetric Ceram）增量修复倒角。将标本在相同的预定区域加载直至折断。记录分离每个碎片所需的力，并对数据进行三因素方差分析，其中组和重新连接技术因素为独立测量因素，折断时间为重复测量因素（第一次和第二次），并进行Tukey检验（α = 0.05）。
主要因素重新连接技术（p = 0.04）和折断时间（p = 0.02）具有统计学意义。颊侧倒角和环形倒角技术在统计学上相似（p > 0.05），且优于仅粘结组（p < 0.05）。第一次折断在统计学上优于第二次折断（p < 0.001）。
在重新连接经牙髓治疗的牙齿时，纤维桩对于增强牙齿结构并非必要。在粘结折断碎片时，与无任何额外预备的简单重新连接相比，颊侧或环形重新连接技术应更可取。用于重新连接的技术均未恢复完整牙齿的抗折强度。
