Keni Shivani, Nambiar Supriya, Philip Pramod, Shetty Siddarth
Department of Orthodontics, Manipal College of Dental Sciences, Manipal University, Mangalore, Karnataka, India.
Indian J Dent Res. 2018 Sep-Oct;29(5):663-666. doi: 10.4103/ijdr.IJDR_720_16.
Whitening of teeth is a popular choice among dental clinicians and patients. However, the changes in enamel structure and composition induced by the bleaching agents cause a decrease in the shear bond strength of brackets leading to premature bracket debonding. Among several methods to overcome this, the most common is delaying bonding by 2-4 weeks. This waiting period can be eliminated by applying an antioxidant (sodium ascorbate) which causes a reversal in the reduction of bond strength.
This study aims to compare the efficacy of a naturally occurring antioxidant (gooseberry) and sodium ascorbate in normalizing the bond strength of enamel to prebleached levels.
Seventy-two extracted premolars were divided into 4 equal groups; 1 group - control group - unbleached teeth, bonded directly, 2 group - bleached with 16% carbamide peroxide (8 h for 1 week), then bonded. 3 and 4 group - similarly bleached, followed by application of 10% sodium ascorbate and gooseberry extract (3 h respectively), then bonded. Bond strength was checked using Instron Universal Testing Machine.
The bond strength of the control group was the highest and that of the carbamide group was drastically reduced. Considerable increase in the bond strength was seen after treatment with sodium ascorbate with negligible difference between sodium ascorbate and control group (P > 0.05).
Treatment with gooseberry extract did improve the bond strength but was not as effective as sodium ascorbate postbleaching.
牙齿美白在牙科临床医生和患者中是一种流行的选择。然而,漂白剂引起的牙釉质结构和成分变化会导致托槽的剪切粘结强度降低,从而导致托槽过早脱落。在几种克服这一问题的方法中,最常见的是将粘结推迟2至4周。通过应用抗氧化剂(抗坏血酸钠)可以消除这个等待期,这种抗氧化剂会使粘结强度降低的情况发生逆转。
本研究旨在比较天然抗氧化剂(醋栗)和抗坏血酸钠使牙釉质粘结强度恢复到漂白前水平的效果。
72颗拔除的前磨牙被分为4个相等的组;1组为对照组,即未漂白的牙齿,直接进行粘结;2组用16%的过氧化脲漂白(8小时,共1周),然后进行粘结;3组和4组同样进行漂白,随后分别应用10%的抗坏血酸钠和醋栗提取物(各3小时),然后进行粘结。使用英斯特朗万能材料试验机检查粘结强度。
对照组的粘结强度最高,而过氧化脲组的粘结强度大幅降低。用抗坏血酸钠治疗后,粘结强度有显著提高,抗坏血酸钠组与对照组之间的差异可忽略不计(P>0.05)。
用醋栗提取物治疗确实提高了粘结强度,但在漂白后不如抗坏血酸钠有效。