Prediction of femtosecond laser ablation parameter on Human teeth using chemical compositional analysis

摘要

Laser-based tooth preparation is an emerging non-invasive technique in dentistry. The knowledge about laser ablation parameters is essential for precise removal of lesion or damaged part of the tooth. The present study introduced a novel technique to determine key laser ablation parameters using elemental analysis so that the clinician can readily obtain the optimized laser processing condition. In pursuance of correlating ablation parameters with elemental composition of teeth, a large elemental variation is induced on the dentin and enamel surface by pretreatment using orthophosphoric acid and Carie care gel. The pretreated enamel and dentin surface were irradiated by 800 nm, 100 fs, Ti:Sapphire laser and the elemental analysis were carried out by EDS. Threshold fluence shows the negative correlation with carbon element (C) and shows a positive correlation with Ca and P whereas the converse is true for effective Gaussian beam radius and effective energy penetration depth. The Ca, P and C show good linearity with all ablation parameters. Despite high sensitivity of C, both Ca and P can be the most reliable probe to predict the laser ablation parameters. The method present a simple and straightforward tool to optimize the laser parameter from the non-destructive evaluation of chemical composition even in case of tooth complexity (age, sex and race). In essence, the chemical composition analysis by a suitable probe will improve the precision of laser surgery and reduce the tissue damage in clinical use.