次氯酸钠和氢氧化钙对牙本质弹性模量和挠曲强度的影响

目的 :评估 5 %次氯酸钠 (NaOCl)溶液和饱和氢氧化钙 [Ca(OH) 2 ]溶液对牙本质弹性模量和挠曲强度的影响 ,以进一步了解根管治疗过程中药物对牙齿机械性能的影响。方法 :取新鲜拔除的完整前磨牙制成标准规格牙本质条 ,经 5 %NaOCl和饱和Ca(OH) 2 溶液处理 ,三点加荷系统测定其弹性模量和挠曲强度。结果 :5 %NaOCl使牙本质弹性模量和挠曲强度显著降低 ;饱和Ca(OH) 2 溶液使牙本质挠曲强度显著降低 ,对弹性模量无显著影响 ;5 %NaOCl处理后再用饱和Ca(OH) 2 溶液处理对牙本质弹性模量和挠曲强度无进一步影响。结论 :5 %NaOCl和饱和Ca(OH) 2 溶液对牙本质的机械性能有一定影响

Effect of Sodium Hypochlorite and Calcium Hydroxide on the Flexural Strength and Elastic Modulus of Dentine

Objective: To evaluate the effect of sodium hypochlorite (NaOCl) solution (5%) and saturated calcium hydroxide (Ca(OH) 2) solution on the flexural strength and elastic modulus of dentine. Methods: Standardized dentine bars were made of freshly extracted premolars and were treated with 5%NaOCl,saturated Ca(OH) 2 solutions individually and consecutively. The flexural strength and elastic modulus of dentine bars were measured by three point loading system. Results: The data revealed a significant decrease in the elastic modulus and flexural strength of the dentine bars treated with 5%NaOCl. Treatment with Ca(OH) 2 reduced the flexural strength but had no significant effect on the elastic modulus. Sequential use of 5%NaOCl and staturated Ca(OH) 2 had no additional weaking effect. Conclusion: 5%NaOCl and staturated Ca(OH) 2 solutions may cause a significant effect on the mechanical properties of dentine.