Shamsan Hanan, Albelasy Nehal F, Farahat Dina S, Mohammad Mohammad H, Hammad Shaza M, Shamaa Marwa S
Department of Orthodontic, Faculty of Dentistry, Mansoura University, Mansoura, Egypt, Phone: +20155112586, e-mail:
Department of Orthodontic, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
J Contemp Dent Pract. 2024 Sep 1;25(9):836-845. doi: 10.5005/jp-journals-10024-3746.
This study evaluates long-term shear bond strength (SBS) and enamel micro cracks (MCs) healing after using adhesive pre-coated brackets (APC).
A total of eighty extracted human premolar teeth were randomly divided into four experimental groups ( = 20 per group): Control group: Teeth underwent indentation but no bracket bonding; group II : Teeth were subjected to indentation without exposure to thermocycling; group III: Teeth experienced both indentation and thermocycling; group IV: No indentation was applied to the teeth; groups III and IV were further divided into two subgroups to simulate different clinical timelines: Subgroup A (n = 10): Teeth underwent 5,000 thermocycles, equivalent to six months of clinical use. Subgroup B (n = 10): Teeth were subjected to 10,000 thermocycles, representing 12 months of use. All precoated brackets underwent debonding with a universal testing machine to assess the SBS, and the adhesive remnant index (ARI) was scored to evaluate the amount of adhesive left on the tooth surface. The study also examined horizontal and vertical enamel cracks, both pre- and post-intervention, across all groups. Crack healing was quantitatively assessed using computer-assisted digital image analysis to ensure precision. For statistical evaluation, ANOVA, Kruskal-Wallis -test, and Tukey's tests were applied to assess differences among the groups.
The Kruskal-Wallis -test demonstrated no significant ARI difference between the groups ( = 0.790). A one-way ANOVA showed a significant difference among all groups ( < 0.001), with lower values observed in the group with indentation without thermocycling compared to all other groups and the groups with 5,000 thermocycles compared to the groups with, 10,000 thermocycles. Crack healing was observed in the control and second groups, and cracks were directly proportional to the number of thermocycles and SBS values.
The study showed that APC FF's SBS increased, and thermal aging did not change the failure pattern. Thermocyclers and SBS affected enamel cracks.
The bond strength of pre-coated brackets and microcrack healing gradually increased with time, while the pattern of bond failure did not change. How to cite this article: Shamsan H, Albelasy NF, Farahat DS, The Effect of Thermocycling on the Shear Bond Strength of Flash-free Brackets and Healing Dynamics of Enamel Microcracks: An In vitro Study. J Contemp Dent Pract 2024;25(9):836-845.
本研究评估使用预涂粘结托槽（APC）后的长期剪切粘结强度（SBS）和釉质微裂纹（MCs）愈合情况。
总共80颗拔除的人类前磨牙被随机分为四个实验组（每组n = 20）：对照组：牙齿进行压痕处理但不粘结托槽；第二组：牙齿进行压痕处理且未经历热循环；第三组：牙齿既进行压痕处理又经历热循环；第四组：牙齿未进行压痕处理；第三组和第四组进一步分为两个亚组以模拟不同的临床时间线：亚组A（n = 10）：牙齿经历5000次热循环，相当于临床使用6个月。亚组B（n = 10）：牙齿经历10000次热循环，代表使用12个月。所有预涂托槽使用万能试验机进行脱粘以评估SBS，并对粘结剂残留指数（ARI）进行评分以评估留在牙齿表面的粘结剂数量。该研究还检查了所有组干预前后的水平和垂直釉质裂纹。使用计算机辅助数字图像分析对裂纹愈合进行定量评估以确保准确性。为进行统计评估，应用方差分析、Kruskal-Wallis检验和Tukey检验来评估组间差异。
Kruskal-Wallis检验显示各组之间ARI无显著差异（P = 0.790）。单向方差分析显示所有组之间存在显著差异（P < 0.001），与所有其他组相比，未经历热循环的压痕组的值较低，与10000次热循环的组相比，5000次热循环的组的值较低。在对照组和第二组中观察到裂纹愈合，并且裂纹与热循环次数和SBS值成正比。
该研究表明APC FF的SBS增加，并且热老化未改变失效模式。热循环和SBS影响釉质裂纹。
预涂托槽的粘结强度和微裂纹愈合随时间逐渐增加，而粘结失效模式未改变。如何引用本文：Shamsan H, Albelasy NF, Farahat DS, 热循环对无闪光托槽剪切粘结强度和釉质微裂纹愈合动力学的影响：一项体外研究。《当代牙科实践杂志》2024；25（9）：836 - 845。
