Surface Modification of Dental Mirrors by ZnO & ZnO/TiO2 Nano-composite to Induce Anti-fog and Anti-microbial Properties

Abstract

Oral health is an important but usually neglected area in developing countries like Pakistan where people rarely visit a dentist but when they do the damage is beyond restoration and usually surgeries have to be performed. This increases burden on the limited number of oral health practitioners in the country. Moreover, there are some technical problems faced by the dental surgeons during surgeries such as fog formation on the dental mirror due to patient’s breathing and oral infections due to the open and invasive nature of the procedure. To deal with these two problems nanotechnology was used for synthesizing a nano coating that can prevent fog formation on the dental mirror along with preventing any post-surgical oral infections. In this study, we synthesized zinc oxide (ZnO) nanoparticles and its composite with titanium dioxide (TiO2) by sol gel method and these nanomaterials were deposited on glass substrate through dip coating technique. The morphology, composition, size and crystalline structure were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS0 and X-ray diffraction (XRD). The nanomaterials and their coatings were then tested for antimicrobial and antifogging properties respectively. Five bacterial strains were chosen against which these nanomaterials were to be tested. Well diffusion assay was used to measure the zone of inhibition and time kill assay was carried out to study the dynamic relationship of our active ingredient with the bacterial strains at different concentrations. Both the nanomaterials had antibacterial activity against all the bacterial strains under study but ZnO was more effective even at lower concentrations. After confirming biological self-cleaning of the nanomaterials the physical self-cleaning of the coated nanomaterials was assessed and for that contact angle and antifogging test was performed. The contact angle of the ZnO coated slide was lower in comparison to the uncoated one and showed hydrophilic nature of the coating. To determine the antifogging activity water was sprayed on the coated and uncoated slides and it was observed that visibility was lost in case of uncoated slides whereas on the coated slides no layer was formed which could affect the visibility. Furthermore, the fog was formed on the uncoated slide upon breathing which further blurred the uncoated glass substrate whereas, despite several tries, fog formation couldn’t be achieved on ZnO coated glass while little fog was formed on the ZnO/TiO2 coated glass substrate. In conclusion these nanomaterials and nanocoatings prevented fog formation and bacterial growth which are the two major problems faced by the dental surgeons and these coatings can be applied to dental mirrors for commercial use as well