An in-vitro study on temperature changes in pulp chamber during orthodontic bonding using high intensity Led curing light at various curing times

Background: Advancements in light-curing technology have significantly improved the efficiency of orthodontic bonding.High-intensity LED curing lights are now widely used as they reduce curing time and enhances polymerization of bonding agents.However, the intense energy output may pose a risk of thermal damage to the dental pulp, particularly when used for prolonged durations.Hence the aim of this study is to evaluate the extent of temperature rise in the pulp chamber at various curing times, thereby contributing to safer clinical protocols and improved patient outcomes.Materials and Methods: 45 extracted human mandibular first premolars were randomly allocated into 3 groups (n = 15 per group).Access cavities were prepared from the apical region, and J-type thermocouples were positioned internally to record temperature changes.Brackets were bonded using a light-cure adhesive, followed by photoactivation with a high-intensity LED curing unit for durations of 3, 6, and 9 seconds, respectively.Real-time intrapulpal temperature variations were recorded and statistically analyzed.Results: A statistically significant increase in intrapulpal temperature was observed across all curing durations (p < 0.05).The greatest temperature rise was recorded following 9 seconds of light exposure (1.60 ± 0.14°C), while an intermediate increase was noted at 6 seconds (0.97 ± 0.30°C) and the lowest occurred with 3 seconds (0.27 ± 0.12°C).Conclusion: Intrapulpal temperature was found to increase proportionally with longer curing durations.Although the use of a high-intensity LED curing unit resulted in temperature elevations, the values remained below the critical threshold of 5.5°C associated with pulpal damage.