How Does Toothbrushing Affect Restorative Materials?

When new restorative dental materials enter the market, clinicians wonder how they will compare to those they have used routinely in their practice. There are differing opinions as to whether resin-ceramic, composite or traditional glass ceramics are most appropriate given the type and location of the restoration required. This article will investigate what we know in regard to the effect of routine toothbrushing and the possible relationship to routine office prophylactic care. 

There have been several studies conducted to assess the effect of toothbrushing and other dynamic forces on various types of restorative materials. When evaluating composites, the effects of brushing are dependent on the type of composite, the load or force of the brushing, the type of toothpaste used and the length of time the restorations are brushed.

Overall, the effects are different for microfill (Adoro, Filtek Supreme, Heliomolar), microhybrid (Four Seasons, Tetric EvoCeram), hybrid (Compoglass F, Targis, Tetric Ceram) and macrohybrid (Grandio) materials. Microhybrid and hybrid materials have more surface deterioration with higher brushing loads (force), with a high correlation between surface gloss and surface roughness. Increased surface roughness has been associated with biofilm adhesion and increased bacterial growth, recurrent caries, gingival irritation, staining and plaque formation^{1, 2}. 

When evaluating ceramic (IPS d.SIGN and polished IPS Empress) using the same study interventions, there was little to no deterioration determined. With ceramic materials, restorations that were glazed only showed wear in the glazed layer after six months. Polishing the restoration after glazing eliminated the wear. 

Stained leucite-based or feldspathic ceramic materials also showed no difference in color after 12 years. In addition, there was no change in roughness in stained ceramic materials. The only situation that caused a slight increase in the roughness of ceramic materials was when they were stained, but not glazed¹. 

The effect of toothbrushing on surface roughness and shade change has been studied for pressable stained leucite (Empress Esthetic) and lithium disilicate-based (e.max Press) materials.  There was no change in Empress Esthetic after 12 years of simulated toothbrushing, regardless of technique and brushing load. There was a statistically significant change in shade and surface roughness of e.max Press with increased brushing time, with any perceived shade changes dependent on the staining technique used⁴. 

The effect of toothbrushing CAD/CAM materials has also been evaluated. As with composite materials, the effect of toothbrushing and effect of water depends on the material and the polishing system used. Newer tooth-colored CAD/CAM materials are more prone to degradation by tooth brushing compared to those with a higher surface hardness³. 

There is a strong correlation between surface roughness and surface hardness. The more ceramic-like the material, the less brushing increased surface roughness. There was a significant increase in surface roughness noted in stained versus polished resin-ceramic materials². 

Polished resin-ceramic CAD/CAM materials show less surface roughness when compared to stained resin-ceramic, with aggressive toothbrushing increasing the roughness of all resin-ceramic CAD/CAM materials². 

Toothbrushing can affect extrinsically-stained feldspathic restorations after 8.5 to 12 years, unless the restorations are glazed after they are stained. A two-step (stain and then glaze) process is more resistant to color degradation or change than when restorations are glazed using a one-step process (stain and glaze together)⁵. 

Further study is needed to determine the effects of dental hygiene on the surface roughness of composite and CAD/CAM materials, since prophylactic polishing pastes require they be abrasive enough to remove plaque and stain^2.  Increased surface roughness of CAD/CAM restorative materials may influence the wear rate, but additional research will help determine whether this is true. 

(Click the link for more articles by Dr. Bob Winter.)  

Bob Winter, D.D.S., Spear Faculty and Contributing Author

References

1. Heintze S, Forjanic M, Ohmiti K, Rousson V. Surface deterioration of dental materials after simulated toothbrushing in relation to brushing time and load. Dental materials. 2010 Apr 1;26(4):306-19.

2.  Can Say E, Yurdagüven H, Malkondu Ö, Ünlü N, Soyman M, Kazazoğlu E. The effect of prophylactic polishing pastes on surface roughness of indirect restorative materials. The scientific world journal. 2014;2014.

3.  Mühlemann S, Bernini JM, Sener B, Hämmerle CH, Özcan M. Effect of Aging on Stained Monolithic Resin‐Ceramic CAD/CAM Materials: Quantitative and Qualitative Analysis of Surface Roughness. Journal of Prosthodontics. 2018 Jul 12.

4.  Flury S, Diebold E, Peutzfeldt A, Lussi A. Effect of artificial toothbrushing and water storage on the surface roughness and micromechanical properties of tooth-colored CAD-CAM materials. The Journal of prosthetic dentistry. 2017 Jun 1;117(6):767-74.

5. Garza LA, Thompson G, Cho SH, Berzins DW. Effect of toothbrushing on shade and surface roughness of extrinsically stained pressable ceramics. The Journal of prosthetic dentistry. 2016 Apr 1;115(4):489-94.