Histopathological and biomechanical changes in soft palate in response to non-ablative 9.3-μm CO2 laser irradiation: an in vivo study.

The purpose of this study was to investigate in vivo the biomechanical and morphological changes in soft palates of Wistar rats from non-ablative irradiation with a 9.3-μm CO2 laser. A blinded, randomized, controlled study was designed with 45 Wistar rats categorized into treated and control sets. The treated set was exposed to 9.3-μm CO2 laser irradiation at an average power of 1.0 W and a single pulse fluence of 0.16 J/cm2 scanned using an automated system at a repetition rate of 315 Hz in a patterned area covering 0.4 cm2 in 6 s. The tissue of each animal was excised and divided into two halves. One-half was sectioned for histopathology, and the other half was used to measure tissue stiffness, which was reported as the effective Young's modulus. Measurements for both sets were taken at three time points: days 1, 21, and 35. There were no significant adverse events or changes in the behavior of the rats over the duration of the study. The treated set exhibited an order of magnitude increase in stiffness relative to the controls, which was maintained over the three time points. Histopathology showed a moderate contraction/disruption of the lamina propria collagen observed at day 1 and collagen accumulation observed at days 21 and 35 in the tissue remodeling phase. Non-ablative 9.3-μm CO2 laser irradiation can safely increase oral mucosal stiffness and can be used as an effective treatment to reduce tissue vibrations that are associated with snoring.