Pulp chamber temperature rise in light-cure bonding of brackets with and without primer, in intact versus restored teeth

ABSTRACT Objective: To evaluate the pulp chamber temperature rise (PCTR) in light-cure bonding of brackets with and without primer, in intact and restored mandibular central incisors (M1), maxillary first premolars (Mx4), and mandibular third molars (M8). Material and Methods: Ninety human teeth were included: M1 (n=30), Mx4 (n=30), and M8 (n=30). Light-cure bonding of brackets was performed in intact (n=60) and restored (n=30) teeth, with primer (n=60) or without (n=30) primer. PCTR was defined as the difference between initial (T0) and peak temperatures (T1), recorded with a thermocouple during light-cure bonding. Differences on PCTR between bonding techniques (primer vs. no primer), teeth types (M1 vs. Mx4 vs. M8), and teeth condition (intact vs. restored) were estimated by ANCOVA, with α=5%. Results: PCTR was significantly higher with the use of primer (2.05 ± 0.08oC) than without primer (1.65 ± 0.14oC) (p=0.02), and in M1 (2.23 ± 0.22oC) compared to Mx4 (1.56 ± 0.14oC) (p<0.01). There was no difference in the PCTR in M8 (1.77 ± 0.28oC) compared to M1 or Mx4 (p>0.05), and no difference between intact (1.78 ± 0.14oC) and restored (1.92 ± 0.08oC) teeth (p=0.38). There was no influence of dentin enamel thickness in the PCTR (p=0.19). Conclusion: PCTR was higher in light-cure bonding of brackets with primer, especially in M1. Light-cure bonding seems less invasive without primer.

摘要：
目的：评估在完整与修复后的下颌中切牙（mandibular central incisors, M1）、上颌第一前磨牙（maxillary first premolars, Mx4）及下颌第三磨牙（mandibular third molars, M8）的托槽光固化粘接操作中，使用底涂剂与不使用底涂剂时的髓腔温度升高值（Pulp Chamber Temperature Rise, PCTR）。
材料与方法：共纳入90颗人牙，其中M1、Mx4、M8各30颗。对60颗完整牙与30颗修复后牙实施托槽光固化粘接，其中60颗使用底涂剂，剩余30颗不使用底涂剂。以热电偶记录光固化粘接过程中的初始温度（T0）与峰值温度（T1），PCTR定义为二者的差值。采用协方差分析（Analysis of Covariance, ANCOVA）评估不同粘接方式（使用vs.不使用底涂剂）、不同牙型（M1 vs. Mx4 vs. M8）及不同牙体状态（完整vs.修复后）间的PCTR差异，检验水准设为α=5%。
结果：使用底涂剂组的PCTR为2.05±0.08℃，显著高于不使用底涂剂组的1.65±0.14℃（p=0.02）；M1组的PCTR为2.23±0.22℃，显著高于Mx4组的1.56±0.14℃（p<0.01）。M8组的PCTR为1.77±0.28℃，与M1组及Mx4组相比均无显著差异（p>0.05）；完整牙组与修复后牙组的PCTR分别为1.78±0.14℃与1.92±0.08℃，二者无统计学差异（p=0.38）。牙本质釉质厚度对PCTR无显著影响（p=0.19）。
结论：使用底涂剂进行托槽光固化粘接时的PCTR更高，尤其在M1中更为显著。不使用底涂剂的托槽光固化粘接对牙体的侵入性更低。