The use of sub-ablative Er:YAG laser irradiation in prevention of dental caries during orthodontic treatment

Abstract

Purpose: This « in-vitro » study had two specific aims: the first, to test using a universal testing machine whether sub-ablative Er:YAG laser irradiation prior to acid etching is effective in orthodontic bracket bonding and secondly using micro-hardness measurements and Scanning Electron Microscopy (SEM) observations to investigate the effectiveness of de-mineralization reduction in enamel treated with sub-ablative Er:YAG laser irradiation followed by fluoride varnish application. Materials and Methods: One hundred and eighty bovine permanent maxillary incisors were selected for shear bond strength testing and microhardness measurements. Sub-ablative Er:YAG laser irradiation was set at a power density of 2.5 J/cm 2 , a frequency of 7 Hz and air/water spray. Brackets were bonded with an auto-curing resin paste. The shear bond strength was measured comparing laser irradiated and non-irradiated enamel surface, followed by SEM observation of the bracket-resin-enamel interface. Microhardness measurements were made on enamel samples before treatment, after samples preparation, and after demineralization. Results: While the adhesion of orthodontic brackets to bovine enamel after sub-ablative Er:YAG laser irradiation and acid etching is comparable to that obtained after conventional acid etching, the effect of laser irradiation associated with topical application of fluoride varnish increases the microhardness of enamel. Conclusion: Sub-ablative Er:YAG laser irradiation before the acid etching doesn't reduce the shear bond whereas when associated with fluoride application it may play a role in caries prevention. Further studies will be necessary to establish the mechanism by which the protective laser activated fluoride effect is achieved.

Application of Laser Irradiation for Restorative Treatments

“…Also, it is reported that Pulsed CO 2 laser irradiation caused enamel surface fusion and inhibition of the subsurface caries-like lesions with 50% success rate [22]. Moreover, increased micro-hardness of enamel surface was detected by several studies after laser application [7, 23]. …”

Er:YAG pre-treatment for bonding of orthodontic bracket: 1 year of in vitro treatment

“…Some studies3,5,9–11 have pointed out increased retention of the resinous material to enamel irradiated with Er:YAG laser. However, further studies need to be conducted in order to prove the efficacy of erbium laser for increasing the bond strength of orthodontic adhesives, since these data are controversial in the literature 6,7…”

Aplicação do Laser na Cariologia: diagnóstico, prevenção e tratamento

“…Os Lasers podem ser classificados em Laser de baixa intensidade e Laser de alta intensidade. O Laser de baixa intensidade, por meio das reações fotoquímicas, pode ser aplicado no diagnóstico e na prevenção da cárie dentária, na desinfecção de canais radiculares, no tratamento de bolsas periodontais e da periimplantite e no clareamento dental 12 . Eles são relativamente barato, de pequeno porte, fácil de transportar e têm múltiplas aplicações em várias áreas da Odontologia 10 .…”

“…O Laser de alta intensidade, por sua vez, pode ser usado no tratamento de doenças malignas, na remoção de tecido cariado, no preparo de cavidades 12 , na cirurgia de tecidos moles e para melhorar a resistência da estrutura do dente à desmineralização 13 .…”

“…A irradiação do Laser no tecido dental leva a uma variedade de alterações estruturais e essas mudanças dependem de parâmetros de irradiação, tais como, comprimento de onda, modo de emissão de Laser, densidade de energia, duração de pulso, taxa de repetição e propriedades de tecido-alvo 12 .…”