Karaarslan Emine Sirin, Secilmis Asli, Bulbul Mehmet, Yildirim Cihan, Usumez Aslihan
Department of Operative Dentistry, Gaziantep University, Gaziantep, Turkey.
Photomed Laser Surg. 2011 Jan;29(1):47-52. doi: 10.1089/pho.2009.2713. Epub 2010 Oct 22.
The purpose of this in vitro study was to measure the temperature increase during the polymerization of a composite resin beneath acid-etched or laser-etched dentin discs.
The irradiation of dentin with an Er:YAG laser may have a positive effect on the thermal conductivity of dentin. This technique has not been studied extensively.
Forty dentin discs (5 mm in diameter and 0.5 or 1 mm in height) were prepared from extracted permanent third molars. These dentin discs were etched with 20% orthophosphoric acid or an Er:YAG laser, and were then placed on an apparatus developed to measure temperature increases. The composite resin was polymerized with a high-intensity quartz tungsten halogen (HQTH) or light-emitting diode unit (LED). The temperature increase was measured under the dentin disc with a J-type thermocouple wire that was connected to a data logger. Five measurements were made for each dentin disc, curing unit, and etching system combination. Differences between the initial and the highest temperature readings were taken, and the five calculated temperature changes were averaged to determine the value of the temperature increase. Statistical analysis was performed with a three-way ANOVA and Tukey HSD tests at a 0.05 level of significance. Further SEM examinations were performed.
The temperature increase values varied significantly, depending on etching systems (p < 0.05), dentin thicknesses (p < 0.05), and curing units (p < 0.05). Temperature increases measured beneath laser-etched discs were significantly higher than those for acid-etched dentin discs (p < 0.05). The HQTH unit induced significantly higher temperature increases than the LED unit (p < 0.05). The LED unit induced the lowest temperature change (5.2°C) in the 1-mm, acid-etched dentin group. The HQTH unit induced the highest temperature change (10.4°C) for the 0.5-mm, laser-etched dentin group.
The risk of heat-induced pulpal damage should be taken into consideration during the polymerization of composite resin after laser etching when the dentin thickness is less than 0.5 mm.
本体外研究的目的是测量复合树脂在酸蚀或激光蚀刻牙本质片下方聚合过程中的温度升高情况。
用铒钇铝石榴石（Er:YAG）激光照射牙本质可能会对牙本质的热导率产生积极影响。这项技术尚未得到广泛研究。
从拔除的恒牙第三磨牙制备40个牙本质片（直径5毫米，高度0.5或1毫米）。这些牙本质片用20%正磷酸或Er:YAG激光蚀刻，然后放置在专门设计用于测量温度升高的仪器上。复合树脂用高强度石英钨卤素（HQTH）或发光二极管装置（LED）进行聚合。用连接到数据记录器的J型热电偶丝在牙本质片下方测量温度升高。对每个牙本质片、固化装置和蚀刻系统组合进行五次测量。记录初始温度读数和最高温度读数之间的差异，并将计算出的五个温度变化值平均，以确定温度升高的值。采用三因素方差分析和Tukey HSD检验进行统计学分析，显著性水平为0.05。进一步进行扫描电子显微镜（SEM）检查。
温度升高值因蚀刻系统（p < 0.05）、牙本质厚度（p < 0.05）和固化装置（p < 0.05）而异。激光蚀刻片下方测得的温度升高显著高于酸蚀牙本质片（p < 0.05）。HQTH装置引起的温度升高显著高于LED装置（p < 0.05）。LED装置在1毫米酸蚀牙本质组中引起的温度变化最低（5.2°C）。HQTH装置在0.5毫米激光蚀刻牙本质组中引起的温度变化最高（10.4°C）。
当牙本质厚度小于0.5毫米时，在激光蚀刻后复合树脂聚合过程中应考虑热诱导牙髓损伤的风险。
