Davari Abdolrahim, Yassaei Soghra, Karandish Mariam, Zarghami Fateme
Department of Operative Dentistry, School of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
J Contemp Dent Pract. 2012 Sep 1;13(5):644-9. doi: 10.5005/jp-journals-10024-1202.
The aim of the present study was to evaluate these two high intensity light curing units regarding microleakage beneath metal and ceramic brackets.
A total of 60 freshly extracted human premolar teeth were randomly divided into four groups of 15 samples; group I: Metal bracket + LED cured, group II: Ceramic bracket + LED cured, group III: Metal bracket + plasma arc cured, group IV: Ceramic bracket + plasma arc cured. After photopolymerization, the teeth were immersed in water and thermocycled (500 cycles between 5 and 55). Specimens were further sealed with nail varnish and stained with 5% basic fuchsin for 24 hours. All of the teeth were sectioned with two parallel longitudinal occlusogingival cuts and examined under a stereomicroscope. The microleakage was measured with a digital caliper and scored from 0 to 3 for marginal microleakage at the bracket-adhesive and adhesive-enamel interfaces from both the occlusal and gingival margins.
Microleakage was detected in all groups. The plasma arc cured group showed less microleakage than light emitting diode (LED) cured in all samples at the enamel-adhesive interface at the gingival margin (ceramic brackets, p = 0.009 and metal brackets, p = 0.005). The plasma arc cured samples showed less microleakage than LED cured in metal brackets at the adhesive-brackets interface at the occlusal margin (p = 0.033). While curing with an LED unit, ceramic brackets displayed significantly less microleakage than metal ones at the gingival margin of adhesive-enamel interface (p = 0.013). The gingival margin in all groups exhibited higher microleakage compared with those observed in occlusal sides in all sample groups (p < 0.001).
The microleakage formation permits the passage of bacteria and oral fluids initiating white spot lesions beneath the bracket base.
本研究旨在评估这两种高强度光固化灯在金属和陶瓷托槽下方的微渗漏情况。
总共60颗新鲜拔除的人类前磨牙被随机分为四组，每组15个样本；第一组：金属托槽+LED光固化，第二组：陶瓷托槽+LED光固化，第三组：金属托槽+等离子弧光固化，第四组：陶瓷托槽+等离子弧光固化。光固化后，将牙齿浸泡在水中并进行热循环（在5℃至55℃之间循环500次）。样本进一步用指甲油密封，并用5%碱性品红染色24小时。所有牙齿均用两条平行的纵向咬合龈向切口切开，并在体视显微镜下检查。用数字卡尺测量微渗漏，并对托槽-粘结剂和粘结剂-牙釉质界面从咬合边缘和龈边缘的边缘微渗漏进行0至3分的评分。
所有组均检测到微渗漏。在龈边缘的牙釉质-粘结剂界面，等离子弧光固化组在所有样本中的微渗漏均少于发光二极管（LED）光固化组（陶瓷托槽，p = 0.009；金属托槽，p = 0.005）。在咬合边缘的粘结剂-托槽界面，等离子弧光固化样本在金属托槽中的微渗漏少于LED光固化样本（p = 0.033）。在使用LED灯固化时，在粘结剂-牙釉质界面的龈边缘，陶瓷托槽的微渗漏明显少于金属托槽（p = 0.013）。与所有样本组咬合面观察到的情况相比，所有组的龈边缘微渗漏均更高（p < 0.001）。
微渗漏的形成使细菌和口腔液体得以通过，从而在托槽底部下方引发白斑病变。
