Effect of Laser Irradiance and Fluoride Varnish on Demineralization Around Dental Composite Restorations

Abstract

Introduction: This study aimed to assess the effects of CO2 and erbium-doped yttrium aluminum garnet (Er:YAG) lasers with and without fluoride varnish on demineralization around composite restorations. Methods: This in vitro experimental study evaluated 96 extracted human premolars. After preparation and restoration of class V cavities in the buccal surface of the teeth with composite resin, they were randomly divided into 8 groups of control, CO2 laser (L1), CO2 laser-NaF (L1F), NaF-CO2 laser (FL1), Er:YAG laser (L2), Er:YAG laser-NaF (L2F), NaF-Er:YAG laser (FL2) and NaF (F). The entire surface of the teeth, except for the restored cavity in the buccal surface and 1 mm around the margin, was coated with two layers of nail varnish. The teeth then underwent pH cycling for 10 days (3 hours in demineralizing solution and 21 hours in remineralizing solution) to artificially induce demineralization. The amount of calcium and phosphorous released into the cariogenic solution was quantified using atomic absorption spectroscopy and spectrophotometry. The Vickers hardness tester was used to measure the hardness of the tooth structure adjacent to composite restoration. Data were analyzed using one-way ANOVA and Tukey's test. Results: The four groups of L1F, FL1, FL2 and L2F showed minimum loss of calcium and phosphorous ions, and the mean hardness of FL1 and FL2 groups was higher than that of other groups. Conclusion:The CO2 and Er:YAG lasers alone have no significant effect on the resistance of tooth structure to cariogenic solution. However, they can exert a synergistic effect when used along with NaF varnish. Fluoride varnish applied prior to laser irradiation confers further resistance to the tooth structure and positively affects its hardness.

Effects of Two Remineralizing agents in Combination with Er:YAG and CO2 Laser Irradiation on Microhardness of Demineralized Enamel: A Preliminary In Vitro Study

“…Remin Pro contains HFX and can fill superficial enamel defects [ 30 , 31 ]. In this regard, Valizadeh et al [ 32 ] concluded that application of Er:YAG and CO 2 lasers alone could not significantly improve the resistance of dental tissues to caries; nevertheless, they had synergistic effects together with sodium fluoride.…”

The impact of Er:YAG laser combined with fluoride treatment on the supragingival plaque microbiome in children with multiple caries: a dynamic study

“…There is still a debate regarding the use of Er:YAG laser irradiation before or after fluoride coating. To achieve better results in enhancing tooth structural resistance and enamel hardness, Valizadeh et al [ 31 ] proposed the application of fluoride varnish or gel before laser irradiation. Er:YAG laser irradiation after the application of fluoride has the potential to melt and seal the dentin tubules, thereby preventing the fluoride from going further into the dentine.…”

Human Enamel Fluorination Enhancement by Photodynamic Laser Treatment

“…There are significant studies in the literature about the effects of laser usage in the fluorination protocols before and after fluoride treatment, evidencing improved fluoride absorption and enamel re-mineralization stimulation [ 6 , 7 , 8 , 9 ]. The active compounds within Tiefenfluorid are sodium fluoride and dispersed calcium hydroxide, which are involved in the newly formed fluoride crystals [ 10 , 11 ].…”