Finite Element Study on Thermal Effects in Root Canals During Treatment with a Surface-absorbed Laser.

Gutknecht, Norbert; Franzen, Rene; Lampert, Friedrich

Purpose: Because unwanted thermal damage may occur during laser treatment of root canals, this study was conducted to determine temperature distributions in the tooth and the periapical tissue using a finite elements model. Materials and Methods: To calculate the temperature distribution, a numerical model of a mandibular molar was developed and edited for use with the finite element (FE) model. For the simulations, density, specific heat, and heat conductivity were included as a set of material constants. Heat deposition was simulated for a surface-absorbing laser system at an average power of 1.5 W whose properties were modeled within the simulation program. This corresponds to the power settings and laser-tissue interaction of an erbium laser with a repetition rate of 20 Hz, pulse energy of 75 mJ, pulse duration of 150 μs, and a full angle of divergence of 25 degrees. Results: The FE analysis of the tooth showed a heat concentration in the region of the apical root canal wall. The temperatures of ca 100°C in this region drop very quickly during the treatment process and are not conveyed to the neighboring tissue, Temperatures of up to 40 to 52° C were found on the root surface for a period of 8 s. Conclusion: The rapid decline of the temperatures on the root surface simulated in this finite element study makes it clear that thermal damage of the surrounding tissue can be avoided if treatment instructions - including power settings and treatment time - are followed.

ROOT canal treatment; LASER surgery; ERBIUM; TEMPERATURE; TISSUES; DENTISTRY; DENTAL care; DENTIN; DENTAL technology

Journal of Oral Laser Applications, 2005, Vol 5, Issue 1, p31

1473-7809

Academic Journal