Performance assessment of novel side firing flexible optical fibers for dental applications

Abstract

BACKGROUND AND OBJECTIVE: Use of lasers in dentistry in root canals of teeth and in periodontal pockets for disinfection would be more effective if energy was delivered laterally. This study examined the energy emission profiles of fibers modified in various ways to enhance their lateral emissions for dental use. MATERIALS AND METHODS: Commercial optical fibers were altered by tube etching with hydrofluoric acid, modified tube etching (after removing the protective polyimide coating), alumina abrasive particle beams, and by etching and particle beams used in combination. Three free-running pulsed infrared lasers (Nd:YAG, Er:YAG, and Er,Cr:YSGG) were employed to test the modified fibers, with 25 fibers for each laser (modified or unmodified). Surface topography of fibers was examined using SEM. Laser emissions forward and laterally were measured, and thermally sensitive paper used to record the emission profiles. Visible tracing of emissions was undertaken using coaxial He-Ne or InGaAsP diode laser emissions. RESULTS: The etching/abrasion/etching combination gave a unique honeycomb surface configuration with grating-like properties, whilst etching alone gave a conical end. Conical and honeycomb tips showed greater lateral and lower forward emissions compared with plain fibers, with fourfold improvements in lateral emission. The most regular lateral emissions were from the honeycomb configuration. CONCLUSION: The honeycomb and the conical fiber modifications show dramatic improvements in lateral emissions. The unique emission profile obtained for the honeycomb fibers could play a significant role in increasing the efficiency of laser delivery for endodontic and periodontal applications in dentistry, as well as in other fields.