Effect of Different Beverages on Colour Stability, Surface Roughness and Surface Hardness of Beauticoat Tooth Surface Coating Material

Gehan G Allam*1, Amr M Abd El Aziz2, Dalia I El Korashy3, Mohammed H Al Sakaf4 and Mohammed Z Khalifa5 1Lecturer Pediatric Dentistry and Dental Public Health Department; Faculty of Dentistry, Ain Shams University 2Professor of Pediatric Dentistry and Dental Public Health Department; Faculty of Dentistry, Ain Shams University 3Professor of Biomaterials Department; Faculty of Dentistry, Ain Shams University 4 Assist. Professor of Operative Dentistry and Endodontics Department, Faculty of Dentistry, University of Aden 5Lecturer Faculty of Dentistry, University of Aden

durability compared to over-the-counter tooth manicures [4,5]. Since that Progress has been made for developing material with better durability and good physical properties that cause little damage to the tooth. Surface pre-reacted glass ionomer has been developed, which possesses physical strength and high levels of controlled fluoride release [6,7]. BeautiCoat (Shofu Inc., Kyoto, Japan) tooth surface coating material showed higher fluoride release compared to conventional sealants, thus, this coating material not only covers the affected discoloured surfaces of teeth and achieves aesthetics, but can also contribute to cavity prevention in the surrounding area, or in the neighbouring teeth, which makes it appropriate recommendation to be used as a temporary tooth surface coating treatment for young adolescents with crown discoloration [7,8].
To ensure good aesthetics, restorative materials must be resistant to discoloration by staining from food and beverages. The colour stability and staining susceptibility of composites, compomers and glass ionomers have been widely investigated [9][10][11]. However, there is lack of studies to assess the influence of beverages on the colour stability of tooth coating material [12]. That's why the aim of our study was to evaluate the effect of immersion in different beverages (orange juice, tea, black cola and distilled water) on the colour stability, the surface roughness and the surface hardness of the tooth-surface coating material.

Materials Used
BeautiCoat™ (Shofu Inc., Japan) a giomer tooth-surface coating material that contains high levels of controlled-release fluoride, Primer A and B and Meta Echant 37% phosphoric acid were used for enamel surface treatment. The study was conducted on toothsurface coating material to investigate colour stability, surface roughness and surface hardness. Giomer specimens preparation: A total of 24 disc specimens of diameter and thickness equal to 6 and 2 mm respectively were constructed from giomer tooth surface coating paste, at room temperature, number coded, then incubated in unionized distilled water at 37•C, for the initial 24 hours to assure complete polymerization of all samples [12]. A 316 stainless steel matrix, 6 mm diameter; 2 mm thickness, was designed and ordered from New Techno_ machine for manufacturing & Supplies, Egypt, and used for specimen preparation.

1.
Shade BW2 giomer tooth surface coating material was selected and used for all the specimens to standardize the degree of polymerization.

2.
The stainless-steel matrix was placed over and acetate strip which also placed over a microscopic slide.

3.
The material was injected into the stainless-steel mold cavity in a single increment.

4.
The material /mold assembly was then covered with an acetate strip.

5.
In order to compact the material and prevent void and bubble formation, a microscopic slide with a 500g weight on it were placed over giomer tooth surface coating material / mold assembly, producing specimens with smooth, highly flat surfaces 6.
The weight was removed after one minute. (Figure 1) 7.
The material was light cured for 20 seconds through the glass slide, according to the manufacturer's instructions, using a LED light-curing unit (Blue phase C8, Ivoclar Vivadent, USA) with an output intensity of 600mW/cm 2 .

8.
The cured disk of Giomer tooth surface coating was removed from the stainless-steel matrix.

9.
Gloss Refine* was applied to both disk surfaces, which was then finished and polished with a buffing Super -Snap disks* ( Figure 1).     of (3.47) to (9.11) at 6 months for b*. While the mean L*value was significantly decreasing over the follow-up period from a baseline of (79.50) to (74. 16 The total color difference after immersion in unionized water was 1.53 after 6 months. ( Table 2). The effect of immersion in different beverages on the surface roughness of the Giomer tooth-surface coating material: The surface roughness of the coating material in this study was estimated by the mean and standard deviation. It was the least immediately before immersion in different beverages (0.060 ± 0.011µm) and increased to (0.081 ± 0.012µm) after one month, reaching (0.097 ± 0.030µm) after 3 months and (0.545 ± 0.386µm) after 6 months. The one-way ANOVA test showed this trend of incremental increase in surface roughness during the follow-up period to be highly significant (p<0.001). The mean surface roughness before immersion in orange was 0.060 ± 0.010µm. It increased to 0.083µm after 1 month and 0.096µm after 3 months, reaching 0.513µm after 6 months. This increase was not found statistically significant (p=0.065). The mean surface roughness before immersion in tea was 0.050 ± 0.001µm. It increased to 0.073µm after 1 month and 0.093µm after 3 months, reaching 0.260µm after 6 months. This increase was not found statistically significant (p=0.136). The mean surface roughness before immersion in cola was 0.066 ± 0.015µm.
It increased to 0.086µm after 1 month and 0.103µm after 3 months, reaching 0.476µm after 6 months. This increase was found to be highly significant (p=0.0001). The mean surface roughness before storage in unionized distilled water was 0.063 ± 0.011µm increasing to 0.630 ± 0.514µm after 6 months. This increase was found to be significant (p=0.043).
When comparing the four immersion beverages, cola was associated with the highest change in immediate surface roughness 0.066µm followed by unionized distilled water 0.063µm, orange 0.060µm then tea 0.050µm (Table 3). The effect of immersion in different beverages on the surface hardness of the giomer toothsurface coating material: The one way ANOVA test showed this trend of diminution in surface micro-hardness during the followup period to be highly significant (p<0.001) (Figure 3)

Discussion
Currently in Pediatric dental practice, young adolescents are becoming increasingly aware of the aesthetics of their dentition.
Tooth discoloration became the most common reason for patient dissatisfaction with their general appearance [15]. Minimal intervention dentistry in the aesthetic management of discolored teeth falls into two main categories of products bleaching and coating agents which are commercially available. This study believed in the coating technology as it appeared to be more convenient with the growing dental structures than the bleaching agents, such as hydrogen peroxide, that could cause significant damage to the soft and hard dental tissues. With the improvement of restorative materials and the demand for aesthetic restorations, giomer has become one of choices for anterior teeth restorations [16,17]. It became even more reasonable to select tea, cola and orange as a staining solution in our study since the consumption of these beverages are presumably higher and more prevalent than other beverages in teenage group in the middle east area.
Color stability was investigated, the total color difference after  [18][19][20][21]. Unfortunately, after 3and 6 months all specimens appeared to be extremely stained as the total color difference became higher and again immersion in tea produced the worst scenario, with 14.11 changes in color difference followed by cola then orange with 13.33 and 9.53 changes in color difference respectively. Tooth surface coating specimens showed the least total color change (1.53) after immersion for 6 months in unionized water that could be clinically acceptable, comparable to that the total color difference after immersion for 1 month in orange and cola 1.80 and 2.82 respectively, which also considered clinically accepted. Apart from discoloration of giomer tooth surface coating material in staining solutions, several additional adverse effects such as increase of surface roughness and decrease of micro hardness were investigated. Among all the immersion beverages, the mean surface roughness after immersion in cola was found to recharge ability of the surface pre-reacted glass ionomer fillers [22,23]. Surface micro hardness was also an investigatory step in this study, the mean surface hardness after immersion in cola was associated with marked decrease all through the follow up period followed by tea then orange. There were no available published studies investigating the surface microhardness of the giomer tooth surface coating material.