Dental adhesives have proliferated the market as composites become the direct restorative material of choice. However, a composite filling is only as good as the adhesive that bonds it to the tooth. At best, the decision of which bonding material to use has become confusing. It is unclear whether we should be deciding based on which generation the adhesive belongs to, the number of steps and components involved in placing the adhesive, or whether the marketing was catchy enough at the last convention. In my practice, the factors that seem to matter most at the end of the day are how well it bonds to the tooth, how long the restoration is going to last, and whether the patients are complaining about sensitivity for the next six months to a year.
I had been using Clearfil SE Bond in the practice, often hailed as the gold standard for self-etching adhesives. These self etching adhesives leave the dentinal smear layer intact allowing for better dentinal sealing, less desiccation of tooth structure, and greatly reduced sensitivity for patients. Recently, however, I switched to Clearfil Protect Bond, new from Kuraray.
Clearfil Protect Bond is a self etching adhesive. It is composed of an acidic methacrylate (HEMA) based primer with a water carrier. Although this is acidic enough to properly etch tooth structure, there is still insufficient research regarding long term bond strengths on unprepared enamel. For this reason, as sometimes happens with anterior teeth, I will etch using phosphoric acid under any extension onto untouched enamel.
The bond component is a bis-GMA, unfilled resin with a camphorquinone activator. The bottom line is that you will get great bonds strengths competitive with any other popular adhesive (over 20 MPa)dentin or enamel bond strength?. This is assuming the correct curing light is used. While most curing lights can activate camphorquinone, there are a few LED sources that are outside of this photoinitiator’s spectrum of blue light. As with all materials, you need to be careful in selecting an LED curing light that is compatible for curing the material you are using, in this case one that covers the range of 400-515nm. Halogen curing lights work perfectly fine.
What really sets Clearfil Protect Bond apart from other adhesives are its two other major components. The bond also contains surface treated sodium fluoride which is slowly released onto tooth structure. The amount of fluoride release is not as good as a glass ionomer and does not preclude judicial use of a glass ionomer liner in certain cases such as deep decay. The other component is MDPB, an antibacterial cavity cleansing monomer found in the primer. This chemical allows for a bacteria free bonding surface and restoration.
Protect Bond is indicated for direct composite or compomer restorations, cavity sealing under indirect restorations, cavity sealing under amalgam restorations, bonding core build ups which are both light and dual cure, and in intraoral porcelain repair. One aspect which I find especially useful is in sealing sensitive root surfaces in areas of recession. You simply apply it as you would for a regular direct composite.
To use Clearfil Protect Bond, apply the primer and let it sit. After twenty seconds, lightly blow off any excess liquid. The bond is then added, lightly blown thin and light cured for only ten seconds. At this point you are ready to place the composite of your choice. If you happen to be applying to a sensitive root surface, Kuraray recommends an additional coat with their Clearfil Liner Bond 2 Protect Liner F, however I simply add another coat of the Protect Bond, light cure again, and get great results with patients.
Is important to remember that when you are using these types of adhesives, eugenol containing products and hemostatics that contain ferric compounds need to be avoided. These will inhibit bond strengths of your final restoration.
Clearfil Protect Bond has great bond strengths, close to zero sensitivity, is antibacterial, and adds fluoride into my restorations. In the past, I often found myself frustrated with removing an old amalgam that has recurrent decay from a tooth that was completely asymptomatic, replacing it with a beautifully crafted esthetic composite, and then having the patient return with the declaration that their tooth never bothered them until we touched it. With Clearfil Protect Bond, those days are just about over.
Clearfil Protect Bond
Excellent bond strengths, flouride release, antibacterial, easy and fast Application.
Self etching primer provides questionable bond strength on unprepared enamel.
The Bottom Line
This is an easy to use bonding system that provides almost complete reduction of post-operative sensitivity.