Bleaching or tooth whitening is getting more 

popular in this world that concerns esthetic [1]

Ab Ghani, Zuryati

Mohamad, Dasmawati

Mohammed Ali, Zaid Hameed

Ooi, Qian Qian

English

Repository@USM

  SURFACE ROUGHNESS EVALUATION OF EXPERIMENTAL DENTAL NANOCOMPOSITE AFTER BLEACHING Dasmawati Mohamad, Zuryati Ab Ghani, Ooi Qian Qian and Zaid Hameed Mohammed Ali  School of Dental Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, MalaysiaIntroduction Bleaching or tooth whitening is getting more popular in this world that concerns esthetic [1].  Carbamide peroxide or CP and hydrogen peroxide or HP are oftenly used as home bleaching agent at concentration range from 10% till 35 %. Studies showed many conflicting result on the effect of bleaching on restorative materials [2, 3, 4]. As for hardness concern, the effects of CP are material dependent [2, 3]. In this study, surface roughness was evaluated as this effect on nanocomposite is poorly studied. Surface roughness is an important clinical criterion of restorative materials which leads to bacteria adhesion and thus secondary caries [5]. Also with the emergence of newly in-house synthesized nanocomposite, namely KeLFiL, the bleaching effect on this material need to be evaluated.  The purpose of this study is to compare the effects of Opalescence PF home bleaching agent (Ultradent, USA) at 10% and 20% CP on surface roughness, Ra of experimental nanocomposites, KeLFiL, with Filtek Z350 (3M ESPE, USA) and TPH3 (DENSPLY, Caulk).  Experimental Materials Three different dental restorative composites were used for this study which were experimental nanocomposites known as KeLFiL, Filtek Z350 (3M ESPE, USA) and TPH3 (DENSPLY, Caulk). Fillers content in KeLFiL, 35% in weight while Z350 and TPH3 at 78.5 % in weight and 75-77 % in weight respectively. Apparatus and Procedures The samples were light cured for 20s from each top and bottom surfaces using Elipar Freelight 2 (3M ESPE, USA) according to manufacturer’s instructions. 54 samples were prepared using acrylic moulds (4mm diameter x 2mm thick) with 18 samples from each material (n=6 controls and stored in distilled water for 14 days, n=6 were bleached with Opalescence 10% carbamide peroxide, n=6 were bleached with Opalescence 20% carbamide peroxide). All samples were stored in distilled water bath of 37ºC for 24 hours before bleaching. Bleaching procedures were carried out for 8 hours for 10% concentration and 2 hours for 20% concentration carbamide peroxide everyday for 14 days. All samples were then polished with Sof-lex (3M, ESPE, St. Paul, MN, USA). Atomic Force Microscopy (AMBIOS Technology, USA) was used to evaluate the surface morphology of composites after 14 days of bleaching and polished. SPSS version 16 was used to evaluate the data and all statistical analysis were conducted at a significant level of P< 0.05 using Anova and Tukey post hoc test. Results and Discussion Results found were shown in Table 1. The mean surface roughness, Ra, for the control group of the samples stored in the distilled water without using any bleaching agent was 79.96 nm for Filtek Z350, 74.55nm for KeLFiL and 79.20 nm for TPH3. There was no significant difference between all the samples, p>0.05. The mean surface roughness, Ra, at 10% CP, was 77.98 nm for Filtek Z350, 71.91 nm for KeLFiL and 78.94 nm for TPH3. Again there was no significant difference between all the samples, p>0.05. The mean surface roughness, Ra, at 20% CP was 65.13 nm for Filtek Z350, 59.92 nm for KeLFiL and 81.83 nm for TPH3. There was also no significant difference between all the samples, p>0.05. The result also showed that either at 10 or 20% of CP all the samples did not give any significant difference.  Table 1. Surface roughness of Filtek Z350, KeLFiL and TPH3 after bleached with 10% CP and 20% CP home bleaching agent. Test materials    Mean surface roughness, Ra, nm (SD) Without bleaching 10% CP 20% CP Filtek Z350 79.96 (10.9)Aa 77.98 (5.5)Aa 65.13 (17.9)Aa KeLFiL 74.55 (17.1)Aa 71.91 (10.5)Aa 59.92 (16.0)Aa TPH3 79.20 (10.3)Aa 78.94 (2.4)Aa 81.83 (7.0)Aa *Within a column, values with the same upper-case superscript letter are not significantly different (p > 0.05, Tukey test). Within a row, values with the same lower-case superscript letter are not significantly different (p > 0.05, Tukey test).    Fig.1 to 3 showed AFM images of each sample surface topography after bleached at 20% CP. Similar pattern of the surface topography for all samples were seen.  Fig. 1 AFM topography 40x40 μm of  Z350 after bleached   with 20% CP   Fig. 2 AFM topography 40x40 μm of  KeLFiL after bleached   with 20% CP  Fig. 3 AFM topography 40x40 μm of  TPH3 after bleached   with 20% CP  The bleaching used in this study did not have any significant effect on the surface roughness for the material tested which were all nanocomposite regardless of their filler loading. Even though KeLFiL has the lowest filler loading at 35% in weight compared with Z350 and TPH3 at 78.5 % in weight and 75-77 % in weight respectively. This is in agreement with Silva et al [6] although the bleaching agent used were different, HP and sodium percarbonate. The Ra values were the same after and before bleaching treatment. However, Attin et al [4] reported that bleaching may exert negative influence on restorative materials.   Conclusion  The evidence from this study, suggest that 14 days of bleaching with 10% CP or 20% CP bleaching agents did not cause changes in surface roughness of the three tested composites. Also KeLFiL performance after bleaching treatment is as similar as the commercial nanocomposites.  References  1. Haywood, V. B. and Heymann, H. O. Nightguard vital bleaching. Quint. Inter., 20 (1989) 173-176. 2. Bailey, S. J. and Swift, E. J. Jr. Effects of home bleaching products on composite resins. Quint. Inter.,  23 (1992) 489-494. 3. Turker, S. B. and Biskin, T. Effect of three bleaching agents on the surface hardness of tooth colored restorative materials. J Prosthet Dent., 89 (2003) 466-473  4. Attin, T., Hannig, C., Wiegand, A.,  Attin, R. Effect of bleaching on restorative materials and restorations—a systematic review. Dent Mater.,  20 (2004) 852–861. 5. Aykent, F., Yondem, I., Atilla, G. O., Solen, K. .G., Mustafa, C. A., Semiha, O. Effect of different finishing techniques for restorative materials on surface roughness and bacterial adhesion. J  Prosthet Dent., 103(4) (2010) 221-227. 6. Silva, M. F. A., Davies, R. M., Stewart, B., DeVizio, W., Tonholo, J., Silva, J. J. G and Pretty, I. A. Effect of whitening gels on the surface roughness of restorative materials in situ. Dent Mater., 22 (2006) 919-924.        

Surface Roughness Evaluation Of Experimental Dental 

Nanocomposite After Bleaching

http://eprints.usm.my/25027/1/Dasmawati%2C_Mohamad_(U._Sains_Malaysia%2C_Kelantan)_259.pdf

Surface Roughness Evaluation Of Experimental Dental Nanocomposite After Bleaching

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