Correct management of periodontal patients in veterinary practice demands a thorough understanding of veterinary dental radiographic anatomy, periodontal probing and many times open evaluation and direct visualization of diseased areas. Stage III periodontal disease in particular requires advanced skills and familiarization with periodontal pathophysiology to make decisions to attempt to grow new supportive tissue adjacent to compromised teeth or extract them.
Periodontal Disease Classification
The degree of severity of periodontal disease relates to a single tooth; a patient may have teeth that have different stages of periodontal disease.
Normal (PD 0): Clinically normal – no gingival inflammation or periodontitis clinically evident.
Stage 1 (PD 1): Gingivitis only without attachment loss. The height and architecture of the alveolar margin are normal.
Stage 2 (PD 2): Early periodontitis – less than 25% of attachment loss or at most, there is a stage 1 furcation involvement in multirooted teeth. There are early radiologic signs of periodontitis. The loss of periodontal attachment is less than 25% as measured either by probing of the clinical attachment level, or radiographic determination of the distance of the alveolar margin from the cemento-enamel junction relative to the length of the root.
Stage 3 (PD 3): Moderate periodontitis – 25-50% of attachment loss as measured either by probing of the clinical attachment level, radiographic determination of the distance of the alveolar margin from the cemento-enamel junction relative to the length of the root, or there is a stage 2 furcation involvement in multirooted teeth.
Stage 4 (PD 4): Advanced periodontitis – more than 50% of attachment loss as measured either by probing of the clinical attachment level, or radiographic determination of the distance of the alveolar margin from the cemento-enamel junction relative to the length of the root, or there is a stage 3 furcation involvement in multi-rooted teeth.
Stage III periodontal disease as described represents a 25 50% loss of the tissue supporting the root. Three tissue types become clinically relevant; bone, cementum and periodontal ligament. Depending upon the character of the bone loss, with proper surgical and postoperative management new tissue can be grown to replace or partially replace that which has been lost. The character of the bone loss is primarily determined radiographically.
Vertical or infrabony bone loss is represented radiographically by a defect adjacent to the tooth root whereby a periodontal probe when passed into the defect resides apical to the level of the adjacent marginal bone. The radiographic void is grossly filled with granulation tissue. Cementum and periodontal ligament are no longer present. Dentin is exposed often with open tubules creating access or microbes to this passage-way to the pulp. Horizontal bone loss is recognized when the bone loss pattern is more uniform whereby a periodontal probe passed into the defect resides on top of the marginal bone level rather than apical to it. These defects commonly are associated with gingival recession exposing tooth roots. These roots are generally void of cementum leaving open dentinal tubules that are exposed to periodontal pathogens as described with vertical defects. This in an important point in both cases in that endodontic status should always be assessed when contemplating periodontal surgery in stage III defects. Periapical lucencies or comparatively large pulp cavities are indications of non-vitality. If these teeth are to be saved endodontic therapy is also required and usually caries a guarded prognosis.
Horizontal defects are not readily amenable to periodontal regenerative therapy. If recession is not present then apically positioned mucoperiosteal flaps following debridement, treatment of exposed roots and bone contouring may be possible. This requires exposure of the affected area through mucoperiosteal flap creation. The defect is debrided to the level of the marginal bone. Proper bone contouring is followed by apical positioning of the flap at the new bone level. Roots are treated with bonding agents to seal the dentinal tubules to eliminate microbe extravasation and sensitivity.
Vertical defects are often very responsive to periodontal regenerative techniques. “Regenerative” is a bit of a misomer. We are creating new tissue not regenerating old tissue. Since defects are intrabony two to four walls of bone surrounding the root provide support for generating new attachment. The technique involves creation of a muco-periosteal flap fo exposure of the region for adequate visualization. Curettage utilizing hand curettes and/or specially designed ultrasonic periodontal instrumentation are utilized to debride all abnormal granulation tissue, tartar, diseased cementum and debris from the defect. This leaves exposed root dentin and bone. Root surface biomodification with EDTA or citric acid creates an optimal surface area for new cementum to populate the root surface. Subsequently a bone grafting material is placed to maintain alveolar bone height at its maximum. A periodontal membrane can then be utilized to deter epithelial migration into the surgical site.
None of these techniques will be successful if owner commitment to diligent home care and periodic cleaning and evaluation under anesthesia is not a priority. Treatment decisions are made here. If the owner cannot commit then extraction is the treatment of choice. Home care involves daily brushing along with adjunctive care with any of a variety of products including water additives, enamel sealants, treats, special dental diets and chlorhexidine gels.
Stage IV periodontal disease exists where greater than 50% of root attachment is compromised. In most cases extraction is necessary at this stage. Mobility may or may not be present. Care must be taken when extracting even mobile mandibular canines and first molars in that mandibular fracture is possible. It should also be mentioned that radiography should be done prior to and after ALL extractions. Proper technique is essential. Especially in the case of stage III and IV periodontal disease periodontal flaps should be utilized to expose diseased tissue for debridement and bone contour. Flaps should be sutured with simple interrupted 4-0 or 5-0 absorbable sutures. Any areas that are suspect should be biopsied especially in areas where unilateral disease exists and/or radiography suggests that neoplasia is a consideration.