Pulp vitality during ultrasonic tooth preparation. Part 2

Area of Science:

• Dentistry
• Prosthodontics
• Dental Materials

Background:

• Ultrasonic devices offer dental applications in hygiene and surgery but present challenges like slow cutting and heat generation.
• Prosthodontic applications of ultrasonic devices are less explored, with heat production being a significant concern due to potential pulp necrosis if temperature exceeds 5.5°C.
• This study investigates intrapulpal temperature increases during ultrasonic finishing line repositioning and polishing.

Purpose of the Study:

• To evaluate the temperature increase in the pulp chamber during finishing line repositioning and polishing using ultrasonic inserts.
• To determine if the temperature rise remains below the critical threshold of 5.5°C, which can cause pulp necrosis.

Main Methods:

• 32 endodontically treated human molars were prepared for prosthetic round chamfer preparations.
• Piezoelectric instruments with regular (DB120) and extra-fine (DB60) diamond grain ultrasonic tips were used for margin repositioning and finishing.
• Intrapulpal temperature was recorded using a thermocouple probe during 60-second test phases, with parameters standardized by a mechanical arm.

Main Results:

• The average pulpal temperature increase was 4.65°C (SD 0.99°C) for the DB120 tip and 5.40°C (SD 0.84°C) for the DB60 tip.
• Neither instrument consistently exceeded the critical 5.5°C threshold, although some individual readings surpassed this limit.
• A statistically significant difference in temperature increase was observed between tips with different granulometries (P=0.013).

Conclusions:

• Ultrasonic tools demonstrate high performance in repositioning and polishing prepared teeth.
• In-vitro analysis indicates that intrapulpal temperature increases during these procedures remain within safe limits.
• The polishing phase is identified as critical; clinicians must manage irrigation and pressure carefully to prevent pulp damage. Further clinical studies are recommended.