Temperatures in the pulpal cavity during orthodontic bonding using an LED light curing unit : An in vitro pilot study

Area of Science:

• Dental materials science
• Biomaterials engineering
• Clinical dentistry

Background:

• Patients undergoing bracket bonding often report thermal sensitivity.
• Modern Light Emitting Diode (LED) curing units can reach intensities up to 3200 mW/cm².
• The thermal effects of these high-intensity units on pulpal temperature are not fully understood.

Purpose of the Study:

• To investigate the intrapulpal temperature increase during bracket bonding using LED light curing units.
• To assess the impact of different parameters (hygienic barriers, light exposure frequency, distance) on temperature rise.
• To evaluate the clinical relevance of manufacturer recommendations for LED curing units.

Main Methods:

• Sixty extracted teeth (incisors, premolars, molars) were used in an in vitro study.
• Temperature increase was measured starting from 37°C.
• Tests were conducted with and without a hygienic barrier, with single or double light exposure, and at 3mm and 4mm distances.
• Metal brackets were bonded in a subsequent test series.

Main Results:

• Significant intrapulpal temperature increases were observed across all test series.
• The highest temperatures occurred with single light exposure without a hygienic barrier.
• Temperatures exceeded 42.5°C in lower incisors and premolars under specific conditions.

Conclusions:

• Bracket bonding with LED curing units, following manufacturer recommendations, can lead to significant pulpal temperature increases (up to 42.5°C).
• The study suggests a need to critically re-evaluate current manufacturer recommendations for LED light curing unit usage.
• Further research is warranted to optimize protocols and mitigate thermal risks during orthodontic bracket bonding.