Cavity Cleaners-Disinfectants

Cleaning teeth prior to etching or prior to conventional cementation of an indirect restoration to remove remnants of provisional cement used to be a simple matter of using a pumice slurry in a prophy cup. However, current thought suggests that the cleaning step should be combined with disinfecting the cavity, just as you would for any other type of wound to the body. Disinfecting the cavity supposedly reduces sensitivity by eliminating or minimizing bacterial growth under restorations. Bacteria reaching the pulp have been implicated in causing sensitivity. Even though the necessity of using a disinfectant to clean a cavity prior to its restoration is still open to question, it seems prudent to use a disinfectant until proven otherwise.

Composition

When the concept of disinfecting teeth was originally proposed by Brannstrom, the recommended agent was benzalkonium chloride (BAC) mixed with EDTA. It was meant to disinfect and partially remove the smear layer. Most current products contain either BAC or 2% chlorhexidine gluconate as the primary active ingredient.

Cleaning

For the cleaning function of the dual-purpose products, you basically scrub the preparation until it is visibly clean. Some products come in dispensing syringes to make application easy, while the others require dispensing onto a cotton pellet, sponge, etc. You can also choose to use a prophy cup if the preparation is readily accessible, such as a veneer, or you can use a StarBrush when access is limited.

Since most of these cleaners are formulated to act without any abrasive agent, you may choose to mix a cleaner with an abrasive such as pumice if the tooth is laden with debris of any sort. We used our CHOICES as cleaners prior to etching with phosphoric acid and a self-etching adhesive to see if there was any negative effect compared to rinsing the tooth with water or scrubbing with a plain pumice slurry. The results are listed in the commentary for each product.

With self-etching adhesives, it appears that an abrasive-type cleaner may be more effective cleaner. Based on our own study, there was significantly less microleakage in Class V cavities when a plain pumice slurry was used to clean cavities prior to applying the adhesive. More leakage was observed when the cavities were cleaned with Consepsis and plain water.

Remoistening/Rewetting

Drying a preparation after etching (when using phosphoric acid) to ensure an adequate enamel etch and then remoistening/rewetting the cavity prior to applying an adhesive that bonds to moist/wet tooth structure used to be a reasonably popular procedure. However, our tests show that not drying in the first place is the more effective procedure. On the other hand, there presumably is a residual antibacterial effect that could help reduce bacterial ingress as a result of microleakage if you use one of these products as a remoistener/rewetter after etching.

Nevertheless, our tests have found lower bond strengths when a disinfectant is used as a remoistener/rewetter.

However, in the case of Consepsis, the bond strengths are still about 23MPa, which should be more than adequate clinically. In addition, chlorhexidine has been shown to inhibit MMP activity (see Introduction to Bonding Agents - Etch & Rinse). Therefore, it seems applying aqueous chlorhexidine such as Consepsis after etching but before the primer/adhesive is a prudent procedure.