Taha N A, Maghaireh G A, Bagheri R, Abu Holy A
Department of Conservative Dentistry, Jordan University of Science and Technology, Irbid, Jordan.
Department of Conservative Dentistry, Jordan University of Science and Technology, Irbid, Jordan.
J Dent. 2015 Jun;43(6):735-41. doi: 10.1016/j.jdent.2015.01.011. Epub 2015 Feb 3.
To compare fracture characteristics of root-filled teeth with variable cavity design restored with a low shrinkage silorane and methacrylate-based resin composite.
77 extracted maxillary premolars were divided randomly into seven groups: (Group 1) intact teeth; (Groups 2-4) MOD plus endodontic access with the buccopalatal width of the occlusal isthmus equals one third of the intercuspal width; (Groups 5-7) MOD plus endodontic access with the buccopalatal width of the occlusal isthmus equals one half of the intercuspal width. Groups 2 and 5 were left unrestored, Groups 3 and 6 were restored with a silorane-based resin composite (Filtek P90) and Groups 4 and 7 with a methacrylate-based resin composite (Z250). Teeth were loaded in a universal testing machine; load and fracture patterns were recorded and compared statistically using 2-way ANOVA and t-test for pairwise comparisons and 1-way ANOVA with Dunnett test for multiple comparisons.
Unrestored teeth became progressively weaker with more extensive preparations, Group 5 (unfilled ½) showed the lowest fracture load among the groups (71±22N, P<0.001). Restorations increased the fracture strength of unrestored teeth regardless of cavity size (P<0.001), but was still significantly weaker than sound teeth, with no significant difference between silorane and methacrylate groups. Failure of restored teeth was mostly adhesive at the tooth restoration interface.
Silorane-based resin composite have no superior strengthening effect over the conventional methacrylate-based resin composite in restoration of root filled teeth. Both materials showed similar fracture patterns.
Root filled teeth are considerably weakened via restorative and endodontic procedures. A direct adhesive restoration will aid in preserving tooth structure as far as it provides enough strength.
比较采用低收缩硅烷和甲基丙烯酸酯基树脂复合材料修复的不同洞型设计的根管充填牙的骨折特征。
77颗拔除的上颌前磨牙随机分为七组：（第1组）完整牙齿；（第2 - 4组）MOD洞型加根管入口，咬合峡部的颊舌宽度等于牙尖间宽度的三分之一；（第5 - 7组）MOD洞型加根管入口，咬合峡部的颊舌宽度等于牙尖间宽度的二分之一。第2组和第5组不做修复，第3组和第6组用硅烷类树脂复合材料（Filtek P90）修复，第4组和第7组用甲基丙烯酸酯类树脂复合材料（Z250）修复。牙齿在万能试验机上加载；记录载荷和骨折模式，并使用双向方差分析和t检验进行成对比较，以及使用单因素方差分析和Dunnett检验进行多重比较，进行统计学比较。
随着预备范围扩大，未修复的牙齿逐渐变弱，第5组（未充填的二分之一）在各组中显示出最低的骨折载荷（71±22N，P<0.001）。修复增加了未修复牙齿的骨折强度，与洞型大小无关（P<0.001），但仍明显弱于健康牙齿，硅烷组和甲基丙烯酸酯组之间无显著差异。修复牙齿的失败大多发生在牙齿修复界面处的粘结。
在根管充填牙的修复中，硅烷类树脂复合材料相对于传统的甲基丙烯酸酯类树脂复合材料没有优越的强化效果。两种材料显示出相似的骨折模式。
根管充填牙通过修复和根管治疗程序会显著变弱。直接粘结修复只要能提供足够的强度，将有助于保留牙齿结构。
