Effect of CO2 Laser and Fluoride Varnish Application on Microhardness of Enamel Surface Around Orthodontic Brackets

Abstract

IntroductionOrthodontic treatment has many advantages such as esthetic improvement, function and self-estimation enhancement. 1Orthodontic appliances make oral hygiene more difficult and increase plaque accumulation. After installing fix orthodontic appliances in the mouth, Streptococcus mutans and Lactobacillus species increase. These bacteria release organic acid that causes dissolution of ions of calcium and phosphate from the enamel surface, which can lead to white spot lesions and this process can occur in 4 weeks.2 White spot lesions are defined as enamel decalcification due to subsurface mineral loss; while 10 to 30 µm of enamel surface remains intact. 3,4 The opaque appearance of the lesion is due to variations in light scattering of decalcified porous enamel. Years after orthodontic treatment, white spot lesions may develop into esthetic problems, because demineralized enamel may absorb colors from drinks and foods. 5,6 When the lesion progresses, remineralization gets tough and sometimes impossible 5,7 ; hence, it is important to prevent the formation of these lesions. Øgaard reported that 5 years after treatment, white spot lesions were more Orthodontic treatment has many advantages such as esthetic improvement and self-esteem enhancement; yet it has some disadvantages such as increasing the risk of formation of white spot lesions, because it makes oral hygiene more difficult. It is rational to implement procedures to prevent these lesions. The present study was aimed to assess the effect of CO 2 laser and fluoride varnish on the surface of the enamel surface microhardness around the orthodontic braces. Methods: Eighty extracted premolar teeth were selected, scaled, polished with nonfluoridated pumic and metal brackets were bonded to them. Then, they were randomly allocated to 5 groups: control (neither fluoride nor laser is used on enamel surfaces), fluoride (4 minutes fluoride varnish treatment of the enamel surfaces), CO 2 laser (10.6 µm CO 2 laser irradiation of the teeth), laserfluoride (fluoride application after laser irradiation) and fluoride-laser (fluoride was applied and then teeth were irradiated with laser). After surface treatment around brackets on enamel, the samples were stored in 0.1% thymol for less than 5 days and then they were exposed to a 10-day microbiological caries model. Microhardness values of enamel were evaluated with Vickers test. One sample of each group (5 teeth from 80 samples) was prepared for SEM (scanning electron microscopy) and the data from 75 remaining teeth were analyzed with analysis of variance (ANOVA) and chi-square tests (α = 0.05). Results:Microhardness mean values from high to low were as follow: fluoride-laser, laser-fluoride, laser, fluoride and control. Microhardness in fluoride-laser group was significantly higher compared with that of the control group. Distribution adhesive remnant index (ARI) scores were significantly different between groups and most of bond failures occurred at the enamel-adhesive interface in groups 2 to 5 and at the adhesive-b...

The Impact of CO2 Laser Treatment and Acidulated Phosphate Fluoride on Enamel Demineralization and Biofilm Formation

“…The laser irradiation without fluoride, in different emission modes, failed to induce remineralization but inhibited demineralization in some situations, which is in accordance with a previous investigation. 3 Placebo gel application followed by the CO 2 laser in continuous, repeated or ultrapulsed modes increased microhardness values. This can be explained by the fact that during pulsed irradiation, the thermal relaxation time is dependent on the geometry and dimensions of the enamel area exposed to laser irradiation, and then it does not influence on the amount of the propagated heat.…”

“…12 On the other hand, authors have shown that fluoride application combined with the CO 2 laser had better results than treatments alone. 3,25,[39][40][41] Aiming to find an alternative method to control initial white spot lesions, we tested the different surface treatments on previously demineralized enamel samples. The laser irradiation without fluoride, in different emission modes, failed to induce remineralization but inhibited demineralization in some situations, which is in accordance with a previous investigation.…”

“…1 The preventive and therapeutic potential of the CO 2 laser for the inhibition of caries on enamel has been discussed. [2][3][4][5][6][7][8][9] However, the parameters for its most effective use are still under debate.…”

Current treatment modalities of orthodontically induced white spot lesions and their outcome – a literature review

“…Mahmoudzadeh et al [32], conducted a study regarding the effect of CO2 laser and fluoride varnish on enamel surface microhardness. They divided teeth in 5 different groups as follows: a control group, a fluoride varnish group, a CO2 laser group, a laser before varnish group and a laser through varnish group.…”

Treatment methods of white spot lesions

“…50,51,55,56 Florürlü vernik ile birlikte 10.6 µm dalga boyunda CO 2 lazer uygulamasının, ortodontik braketlerin etrafındaki minenin mikrosertliğini arttırmada başarılı bulunmuş ve kullanımı tavsiye edilmiştir. 57 Lazer teknolojisinin, makul bir maliyetle elde edilebildiği ve klinikte uygulanabildiği takdirde çürük önlemede gelecek vadettiği belirtilmektedir. 55…”