Presentation Blocks: 03-23-2018 - Friday - 11:00 AM - 12:15 PM

Title: Effects of CO2 Laser and Fluoride Treatment on Enamel Hardness


Jayapriyaa Shanmugham, Boston University
Hammam Bahammam (Presenter)
Boston University

Yuwei Fan, Boston University
Jeonghoon Kim, Boston University
Dan Nathanson, Boston University
Athanasios Zavras, Boston University


Objectives: To evaluate effects of CO2 laser with and without fluoride on enamel hardness (EH) in permanent teeth. Effect of demineralization on treated and untreated teeth was also analyzed.

Methods: Extracted human permanent molars (n = 60) without any decay were selected for this in-vitro study and randomly assigned to seven groups that included treatment with 1) CO2 laser (LightScalpel LS-1005) at 2 and 4 watts 2) with 5% sodium fluoride varnish, and varying sequential combinations of the two. Knoop hardness test was conducted with a microhardness tester (Buhler Micromet 2003) to measure EH at baseline, post-treatment, and following demineralization. Demineralization was achieved by placing the teeth in Coke for 30 minutes. Differences in EH values within treatment and between treatment measurements were evaluated using non-parametric univariate analyses.

Results: When comparing within each group between baseline and post-treatment, laser at 2 watts significantly increased the EH when used alone (p-value = 0.04) or followed by fluoride (p-value = 0.04). After demineralization, the group treated with fluoride first then laser at 4 watts showed the least EH reduction (p-value = 0.04). When evaluating between groups, all of the treated teeth showed a significant increase in EH when compared to untreated teeth (p-value = 0.0001); particularly the teeth treated with laser at 2 watts showed the highest increase in EH. Furthermore, laser 2 watts alone (p-value = 0.04) or followed by fluoride (p-value = 0.04) significantly increased the EH compared to the group with fluoride before laser at 2 watts. In demineralization process, teeth treated with fluoride alone showed the highest hardness loss.

Conclusions: CO2 laser treatment can be beneficial in increasing enamel hardness when used in conjunction with fluoride. In particular we observed that laser at 2 watts followed by fluoride was most effective and can be useful in preventing decay.