In-vivo Occlusal Caries Prevention by Pulsed CO2-Laser Treatment

High caries prevalence in occlusal pits and fissures warrants novel prevention methods. In-vivo 86% reduction in smooth surface demineralization following short-pulsed 9.6µm CO₂-laser irradiation was recently reported (Rechmann et al 2008). "Objectives:", To conduct a blinded 12-month pilot clinical trial of occlusal pit and fissure caries inhibition using the same CO₂ laser irradiation conditions. "Methods:", 20 subjects, average age 13 years (range 11–16), were recruited.  At baseline, second molars were randomized into test and control groups, assessed by International Caries Detection & Assessment System (ICDAS) and Quantitative Light-Induced Fluorescence (QLF). An independent investigator irradiated test molars with a CO₂-laser, Pulse System. Inc (PSI) (Model #LPS-500, Los Alamos, New Mexico), wavelength 9.6μm, pulse duration 20μs, pulse repetition rate 20Hz, beam diameter 1,100μm, average fluence 3.4±0.3J/cm², 20 laser pulses per spot, straight handpiece.  At 6- and 12-month recall, teeth were assessed by ICDAS and QLF. "Results:", 17 subjects completed the 6-month and 14 the 12-month recall.  ICDAS:  At 6-months, average ICDAS score changes (mean±SE) were for test 0.50±0.15 and control molars 0.53±0.17, and at 12-months 0.40±0.19 and 0.57±0.23 respectively.  The results showed no statistically significant differences (P>.05, Student t-test). QLF:  At 6-months, average ΔF (%mineral loss) changes (mean±SE) were for test 0.78±0.38 and 0.36±0.75 for control molars with no statistically significant differences (P>.05, Student t-test).  At 12-months, average ΔF changes were -1.13±0.34 for test and 0.31±0.38 for control molars. 12-month results showed a statistically significant difference (P=.01, Student t-test). "Conclusion:", Although specific CO₂-pulsed-laser irradiation markedly inhibited demineralization in smooth surfaces, the same result was not found for pits and fissures, likely due to design limitations of the laser delivery system. Only the QLF 12-month results indicated enhanced caries inhibition, promising future success with an optimized newly designed laser handpiece. Supported by NIH/NIDCR grant DE09958.