Practical small animal periodontology (Proceedings)
The largest portion of our dentistry case load in everyday practice involves the treatment of periodontal disease. No other oral malady will present itself more commonly. At the same time proper evaluation of the stage of periodontal disease is determined with probing, visual examination and radiographically. This lecture will take a look at several examples of cases that are commonly encountered in veterinary practice and take you through the steps required to resolve these cases therapeutically. Infrabony pocket repair is one of the most challenging aspects of periodontal care. The discussion below is an adjunct to the case format lecture and is provided for future reference.
The goal and rationale in approaching surgical therapy for infrabony pockets is to create the ideal environment for new attachment of periodontal ligament fibers to new cementum and for gingival epithelium to adhere to tooth structure. This process starts with the provision of adequate visualization with the aid of a mucoperiosteal flap. This allows the operator to thoroughly clean diseased tissue from the defect and the gingiva through root planning and subginvial curettage. Once completed, a variety of products may be used to enhance the healing effort to create new attachment.
Several compounds are currently in use to biomodify the root surface to enhance new attachment. Discussion of all such compounds is beyond the scope of this paper, however citric acid and 24% EDTA are two common compounds traditionally used for root surface treatments. Both act to demineralize the root surface in an attempt to expose collagen fibers creating an ideal surface for population with periodontal ligament cells. It has been shown that treatments with both agents attract fibroblasts that act with other cells to initiate the process of collagen synthesis which is the structural component of periodontal ligament fibers. 24% EDTA was chosen in this case for several reasons. Although effective at demineralizing the root surface citric acid has a necrotizing effect on the surrounding tissues due to its low ph. 24% EDTA operates at a neutral ph and promotes the healing of periodontal tissue. Materials used for grafting in infrabony defects are also classified regarding their ability to be osteogenic, osteoinductive or osteoconductive. Osteogenic compounds have cells capable of synthesizing new bone within the compound itself. The most common example of an osteogenic graft material is cancellous bone grafts from the patient. The added anesthesia time and technical difficulty involved with obtaining this material makes it a less viable choice despite the desirability of its osteogenic nature. Osteoinductive materials contain cells that promote patient cell transformation to osteoblasts. One such material is decalcified freeze-dried bone allograft (DFDBA) which contains bone morphogenic protein. Although an excellent alternative to autogenous bone grafts cost is a major deterrent with this material. Osteoconductive compounds act as a matrix for migration of cells that aid in the production of new bone. Examples include hydroxyapatite, tricalcium phosphate and bioactive glass. Bioactive glass was the compound used in this case for several reasons. It is approved for veterinary use as a grafting material to treat infrabony defects. It has been shown to be effective in treating infrabony defects in humans and in the dog and cat.It is capable of impeding the downgrowth of epithelial tissues that prevent new attachment of the periodontal ligament and has proven superior to hydroxyapaitie and tricalium phosphate in its ablility to do so. It has also been shown to have an antibacterial effect against oral microbes in vitro.
Consideration was given to the use of a membrane to aid exclusion of unwanted tissue migration into the pocket during healing. Research involving Class II furcations in humans has shown no benefit when using a membrane over that of bioiactive glass. The favorable long term outcome described in this case report supports the use of bioactive glass and 24% EDTA in the manner described to treat infrabony defects in dogs.