Surface Processing: An Elegant Way to Enhance the Femtosecond Laser Ablation Rate and Ablation Efficiency on Human Teeth

Background and Objectives: The employability of the non-invasive femtosecond laser ablation technique for dental treatment has been severely limited by its low ablation rate despite the advantage of minimal tissue damage. The study explores a means of improving the femtosecond laser ablation rate and efficiency by physiochemical surface modification. Materials and Methods: Surface modification of dental hard tissues has been carried out by food graded orthophosphoric acid and Carie care gel pretreatment. The laser ablation characteristics were studied by using a Ti:Sapphire laser (10 kHz, 10 mm/s, 100 fs, 800 nm) to ascertain the influence of pretreatment. Surface morphology and chemical composition were obtained by using an optical profiler, SEM and EDAX. Results: The ablation threshold fluence decreased by almost one-third whereas the ablation rate and ablation efficiency nearly tripled upon pretreatment. The microstructural and compositional analysis clearly reveals that surface modification and demineralization reduce the threshold fluence and increase the ablation rate by effective utilization of the laser beam energy. The pretreatment effect is more pronounced in orthophosphoric acid as compared with Carie care gel. Conclusions: Physiochemical surface modification can be an efficient method to improve the laser ablation rate and ablation efficiency. Compositional analysis can be an elegant tool for pre-surgery determination of laser ablation characteristics. Clinical Significances: Pretreatment surface modification can be an effective way to overcome the limitation of the femtosecond laser for tooth preparation in the clinical setting by strongly enhancing the ablation rate. An enhanced ablation rate along with de nova prediction of ablation characteristics will enable the clinician to perform dental surgery in real time with minimal tissue damage. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.