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

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 alpha=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.