Dentin Bonding- It is not for every one!

Dentin bonding is the commonly used term for the application of unfilled or partially-filled restorative materials to exposed dentin and enamel surfaces to seal or close exposed enamel and dentin tissue. The use of adhesives has many applications in veterinary dentistry, both as part of composite resin application or a “stand-alone” therapeutic option. In this presentation we will focus on the use of resin adhesives to treat uncomplicated crown fracture or acutely exposed dentin tissue. In order to understand when to use dentin sealants, it is also important to understand when not to use them. This requires a discussion of anatomy and the dentin-pulp complex as well as a discussion of product choices.

The term bonded sealant is used loosely in dentistry and can be confusing if taken literally. Hours can be spent on the discussion of the various types of products available to use for this purpose. These products are micromechanically interlocked into the dentin and enamel with resin tags that interlock into the prepared demineralized dentin collagen fibril mesh, creating a dentin-resin hybrid layer. They can be used alone to seal the tooth surface or to bond or adhere composite resins or other materials to the tooth. The typical products used can be resins, glass ionomers, or pit and fissure sealants. They can be unfilled or filled.

Products used as bonded sealants need to be chosen based on multiple factors and I would posit that one size fits all may not be applicable in our veterinary patients. The majority of our products are designed for human usage, occlusal forces, and oral environment. Our veterinary patients (primarily dogs) have a different oral environment, different occlusal forces, dietary substrates, more densely packed and ovoid dentin tubules, and thinner enamel.

There is no consensus on when to apply a dentin adhesive to “seal” uncomplicated crown fractures and enamel fractures. There are multiple factors that should be considered when making this decision and, in some areas, the research is limited or inconclusive for treatment of uncomplicated crown fractures and defects. As part of the dentin-pulp response to injury, the odontoblasts can create regenerative dentin or the mesenchymal cells in the pulp tissue can differentiate and replace lost odontoblasts to make reparative dentin. If sufficient barrier is created and reversible pulpitis is present, the tooth can survive if the source of irritation or trauma is removed. The preparation for and placement of a bonded sealant may disrupt or destroy the barriers put in place by the tooth.

Intraoral imaging is required and should be considered in conjunction with a complete periodontal examination. If radiographic findings of endodontic disease or terminal periodontal disease are present, alternative therapy (root canal therapy, periodontal surgery, or extraction) should be considered.

A review of application and use principles will be included.