温度与机械疲劳对不同表面处理后的石英纤维桩与根管粘结强度的影响

目的比较温度和机械疲劳对不同表面处理的石英纤维桩和根管牙本质的剪切粘结强度的影响。方法 54颗大小相近的完整人上颌中切牙根疗后截冠并预备桩道。54根石英纤维桩按不同表面处理随机均分为机3组：硅烷偶联剂处理组（A组）、24%过氧化氢液处理组（B组）及24%过氧化氢液＋硅烷偶联剂处理组（C组）。粘结修复后每组机械疲劳、温度疲劳各处理6颗,余6颗为对照。机械疲劳组采用30N的载荷以1.25 Hz的频率,沿着与牙体长轴呈135°角度进行10000次的循环加载。温度疲劳组在5～55℃冷热水中循环10000次,每一温度停留30 s,过渡20 s。对照组储存在37℃生理盐水1周。各组每牙按根颈1/3,根中1/3,根尖1/3切成3个2 mm的薄片进行微推出试验,记录数值并进行方差分析。结果在根颈部位,机械疲劳各组剪切粘结强度均低于对照组,差异有统计学意义（P〈0.01）,温度疲劳A、B组剪切粘结强度低于对照组,差异有统计学意义（P〈0.01）,温度疲劳C组剪切粘结强度差异无统计学意义（P〉0.05）。在根中部位,机械疲劳A组剪切粘结强度低于对照组,差异有统计学意义（P〈0.05）,机械疲劳B、C组剪切粘结强度差异无统计学意义（P〉0.05）;温度疲劳A组剪切粘结强度低于对照组,差异有统计学意义（P〈0.05）,温度疲劳B、C组剪切粘结强度差异无统计学意义（P〉0.05）。在根尖部位,三种表面处理方法均显示剪切粘结强度差异无统计学意义（P〉0.05）。结论机械和温度疲劳循环均可以降低三种表面处理的石英纤维桩与根管牙本质的剪切粘结强度,且在根颈处的影响最明显,其中对C组的影响最小。

The effect of temperature and dynamic loading on quartz fiber posts conglutinate with root dentin

Objective To compare the effect of surface treatments on the push-out shear bond strength of quartz fiber posts to three root regions under dynamic loading and Thermocycling.Methods Fifty-four extracted human maxillary central incisors were decapitated and treated with complete root canal therapy.Then prepare the path of post.54 quartz fiber posts were randomly assigned into three groups according to the chemical surface treatments：treat with silane agent（Group A）,treat with 24% Hydrogen peroxide（Group B）,treat with 24%Hydrogen peroxide,then with silane agent（Group C）, Posts were inserted using the resin adhesive system.Each group quartz fiber posts were treated according to dynamic loading（n = 6）,Thermocycling（n=6） and contrast（n=6）.The dynamic loading group samples were applied to 30 N load with 1.25 Hz at 135 degrees angle with tooth long axis,and treated for 10 000 cycling on fatigue test machine.Thermocycling group samples were subject to thermal cycling for 10000 times（treated temperature：5℃/55℃,dwell time：30 s,transfer time：20 s）.Control group samples were saved in Sodium Chloride for one week at 37℃.After treatment each root was sectioned into three sections with 2 mm thick.A push-out test was performed to measure bond strengths.Data were analyzed with ANOVA.Results In the cervical of the root,the push-out bond strength was significant weak after dynamic loading treatment when compared with control（P0.01）.However,in the middle of the root,the push-out bond strength only A group was significant infirmness after dynamic loading treatment when compared with control（P0.05）.In comparison of Thermocycling treatment with control samples,the cervical third of the root,the push-out bond strength was significant lower in A and B group after Thermocycling treatment（P0.05）.In the middle of the root,the push-out bond strength from A group of Thermocycling treatment was markered lower than control（P0.05）. However,in the apical of the root,there were no significant different in the push-out bond strength among any group（P0.05）.Conclusion Dynamic loading and Thermocycling treatment could reduce the push-out shear bond strength of quartz fiber posts on tooth root,especially in the cervical third of the root.But there is no significant effect on C group.