Optical properties and color of porcine gingiva

Laser interaction with oral tissues is dependent upon the tissues physical properties. Previous studies measured the absorbance coefficient of individual components of the tissues. The purpose of the present study was to determine the reflectance, transmittance and absorbance of the whole tissue: porcine gingiva. Therefore, 2x4 mm sections consisting of attached and free gingiva from porcine mandibles, 1.2+/- 0.2 mm thickness, were measured using a spectrometer for reflectance (R) and transmittance (T), and the absorbance (A) was calculated. In order to fully characterize the optical properties of the soft tissue, the color of porcine gingiva was also measured utilizing the L*a*b* system. The average R, T and A among the specimens were determined for each wavelength (200-2500 nm) and the respective spectral curves determined at 95% confidence level. For the laser emission wavelength frequency-doubled Alexandrite (377nm) the average values were: R=25.8%; T=0.6%; A=73.6%. For the laser emission wavelength Nd:YAG (1064nm) the average values were: R=25.8%; T=66%; A=3%. For the laser emission wavelength diode (980nm) the average values were: R=30%; T=58%; A=12%. Color of the gingival tissue measured in reflectance had higher L*, a* and b* values as compared to color measured in transmittance.