Inhibition of enamel demineralisation using "Nd-YAG and diode laser assisted fluoride therapy"

Combined Effects of Topical Fluorides and Semiconductor Lasers on Prevention of Enamel Caries: A Systematic Review and Meta-Analysis

Objective: To compare the effects of combined treatment of topical fluoride and semiconductor laser (F&L) with topically using fluoride (F) on remineralization and prevention of enamel caries. Background: There is no agreement on whether semiconductor lasers can promote the effect of topical fluoride on the remineralization and prevention of dental caries. This study is the first systematic review and meta-analysis to investigate the pooled effect of data from studies that compared the combined use of semiconductor lasers and topical fluorides with the single use of fluoride on remineralization and prevention of caries. Methods: We performed literature search on Scopus, Web of Science, and PubMed. The keywords were as follows: ((diode lasers) OR (diode laser) OR (quantum cascade laser) OR (quantum cascade lasers) OR (Gallium Aluminum Arsenide lasers) OR (Gallium Aluminum Arsenide laser) OR (GaAlAs lasers) OR (GaAlAs Laser) OR (semiconductor laser) OR (semiconductor lasers)) AND ((caries) OR (dental caries) OR (remineralisation) OR (remineralization) OR (demineralization) OR (demineralisation)) AND fluoride. We carried out meta-analysis to compare the microhardness of demineralized enamel, lesion depth (LD), and percent reduction of calcium (Ca%) of sound enamel receiving F&L with F. Results: The search identified nine laboratory studies, which used 445 to 980 nm semiconductor lasers with various fluorides. The standard mean difference of microhardness of demineralized enamel between F&L and F was 1.06 [95% confidence interval (CI): 0.12 to 2.00, p = 0.03]. No difference was found in LD (95% CI: -1.63 to 0.10, p = 0.08) and Ca% (95% CI: -0.52 to 1.28, p = 0.40) on sound enamel between the two groups. Conclusions: Semiconductor lasers enhance the effect of fluoride on remineralizing but not on preventing enamel caries. Moreover, substantial heterogeneity was found among the studies, and the results should be interpreted cautiously.

Laser-assisted prevention of enamel caries: a 10-year review of the literature

Since the invention of lasers in dentistry, investigations in caries prevention by the use of laser radiation have been proposed. There are several mechanisms stated for this purpose such as photothermal and/or photochemical interaction processes with the enamel. Alone or in conjugation with topical fluoride application, this treatment modality may improve enamel acid resistance in high-caries-risk populations. Data collection was done by searching the keywords caries, prevention, and laser in PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar. Lasing protocols of the collected literature and their effectiveness as well as examination methods used to verify treatment outcomes have been evaluated. One hundred eighteen publications were found for the last 10 years. The wavelengths investigated for caries prevention are mainly located in the near and the mid-infrared spectral range. In the evaluated period of time, investigations using CO₂; Er:YAG; Er,Cr:YSGG; Er:YLF; fundamental, second, and third harmonic generations of Nd:YAG; diodes; and argon ion lasers were found in the databases. Accounting for 39% of the literature, CO₂ laser was the most examined system for this purpose. Reviewing the literature in this narrative review showed that all laser systems presented a positive effect in varying degrees. Laser irradiation could be an alternative or synergistic to topical fluoridation for enamel caries prevention with longer lasting effect. Further research should be focused on selecting proper laser settings to avoid damage to enamel and developing effective evidence-based clinical protocols.

SEM Evaluation of Enamel Surface Changes and Enamel Microhardness around Orthodontic Brackets after Application of CO2 Laser, Er,Cr:YSGG Laser and Fluoride Varnish: An In vivo Study

Introduction

One of the most undesirable consequences of orthodontic treatment is occurrence of enamel demineralization around orthodontic brackets. Numerous in vitro studies have reported the prevention of enamel demineralization by surface treatment with lasers and fluoride varnish.

Aim

To evaluate the changes on the enamel surface and microhardness around orthodontic brackets after surface treatment by CO₂ laser, Er, Cr:YSGG laser and fluoride varnish in vivo.

Materials and Methods

A double blind interventional study was carried out on 100 premolars which were equally divided into five groups, out of which one was the control group (Group 0). The intervention groups (Group I to IV) comprised of patients requiring fixed orthodontic treatment with all 4 first premolars extraction. Brackets were bonded on all 80 premolars which were to be extracted. Enamel surface treatment of Groups I, II and III was done by CO₂ laser, Er, Cr:YSGG laser and 5% sodium fluoride varnish respectively and Group IV did not receive any surface treatment. A modified T-loop was ligated to the bracket and after two months, the premolars were extracted. Surface changes were evaluated by Scanning Electron Microscopic (SEM) and microhardness testing. Comparison of mean microhardness between all the groups was assessed using post-hoc test with Bonferroni correction.

Results

Group I showed a melted enamel appearance with fine cracks and fissures while Group II showed a glossy, homogenous enamel surface with well coalesced enamel rods. Group III showed slight areas of erosions and Group IV presented areas of stripped enamel. Significant difference was observed between the mean microhardness (VHN) of Group I, Group II, Group III, Group IV and Group 0 with p<0.001. A significant difference of p<0.001 was observed while comparing Group I vs II,III,IV,0 and Group II vs III,IV,0. However, difference while comparing Group III vs IV was p=0.005 and difference between the mean microhardness of Group 0 vs Group III was non significant.

Conclusion

Surface treatment with Er,Cr:YSGG laser causes a positive alteration of the enamel surface increasing its ability to resist demineralization with optimum microhardness as compared to CO₂ laser and sodium fluoride varnish.