Over the years there has been contradictory information about placing a bevel on the margin of a posterior composite. I learned to place a bevel on the margins of all of my composite preparations. The rational was that it increased enamel bonding. The literature supports that a small bevel does increase the surface area of enamel. This increased surface area in some studies results in a 25% increase in bond strengths of the final restoration. As dentin adhesives have improved over the years the importance of increasing bondable enamel surfaces has lessened and some claim is no longer necessary.
Another question is about the ability of composite to function against a bevel. Unlike most of our restorative materials composite does very well in thin layers and does not require a “minimum” thickness of material to achieve it’s physical properties. the presence of a bevel significantly increases marginal adaptation when placing composite restorations. This adaptation increase has multiple benefits from decreased leakage, decreased post operative staining at the margins, and increased esthetic blending. The presence of a bevel also has been shown to mitigate the effect of polymerization shrinkage, which again will increase the seal and longevity of the marginal interface and decrease post operative sensitivity.
In the US most dental schools are teaching the placement of a bevel on all composite preparations. Interestingly, on most of the board exams across the country the placement of a bevel is optional. The belief is this more accurately reflects what is happening in the majority of dental offices which is no bevel. The only technique change is the limited time it takes to place the bevel and the benefits are many. I for one hate when I can see the interface between the tooth and the margin, so this alone is sufficient motivation to bevel.
I agree with your points ,But in case of bevels, i think that the effectiveness of retention is according to how large the surface area of the bevel is .in other words,the smaller the( s a) of the bevel the stronger the grip,however i depend in 50 percent about ,by doing slots and grooves this is a very effective way,and finally the most important is the type and quality of the composite material is very important as well as following (exactly)the instructions of the company,(nano filler is better than micro filler ones).
Thanks Lee,
Can you please clarify- are you talking about gingival bevels in enamel, proximal bevels, occlusal bevels, or all of the above? I’ve been placing more bevels (everywhere) lately with my increased magnification loupes- hoping to enhance my peripheral seal and get a better shade transition. I’m also intrigued by the Kavo sonic handpiece that places bevels close to the adjacent tooth with less risk of damage. Any experience there?
I have not had a chance to use the Kavo sonic handpiece. As for where to bevel the concepts apply to any cavosurface margin, and I agree I have been adding them back in more for the same reasons!
Hello dr brady thanks for the most informative blog!
One question:if you dont use the sonicsys in order to place bevels in proximal preparations could you specify the burs you are using. What about gingival proximal walls with a minimal enamel thickness? Do you still opt for a gingival bevel inthose cases?
Thanks!
I use a mosquito diamond in a FG high speed for my bevels. As to the gingival margin, I will not sacrifice the ability to bond to enamel in order to bevel. The bevel for me is a great esthetic blending tool on the occlusal and labial and lingual walls of the box, but with thin ginigval floor enamel I will not bevel this surface.