The ABCs of veterinary dentistry: P is for periodontal pockets

Periodontal nomenclature

An alveolectomy is the removal of some or all of the alveolar bone.

An alveoloplasty is a form of alveolectomy performed to restore physiological contours or achieve smooth contours of the alveolar bone.

An apically positioned flap is moved apical to its original location.

An envelope flap is retracted away from a horizontal incision; there is no vertical incision.

Closed periodontal debridement involves the removal of damaged, infected, inflamed or necrotic tissue from periodontal pockets and dental deposits from the tooth surface without the creation of a flap; this includes gingival curettage (or excisional new attachment procedure) and root planing.

A coronally positioned flap is moved coronal to its original location.

Gingival curettage refers to the removal of damaged, infected, inflamed or necrotic tissue from the soft tissue lining of a periodontal pocket.

Gingival enlargement is a clinical term referring to the overgrowth or thickening of gingiva in the absence of a histological diagnosis.

A gingival flap contains gingiva.

Gingival hyperplasia is a histological term referring to an abnormal increase in the number of normal cells in a normal arrangement resulting in clinical gingival enlargement.

Gingival recession refers to root surface exposure caused by apical migration of the gingival margin or loss of gingiva.

Gingivectomy refers to removal of some or all gingiva surrounding a tooth.

Gingivoplasty is a form of gingivectomy performed to restore physiological contours of the gingiva.

A mesiodistally or distomesially positioned flap is moved distal or mesial to its original location along the dental arch; this flap has also been called a laterally positioned flap.

Open periodontal debridement is the removal of damaged, infected, inflamed or necrotic tissue from periodontal pockets and dental deposits from the tooth surface after flap creation; this includes the removal of affected gingiva and granulation tissue upon flap creation and management, root planing, and osseous resective procedures such as an alveolectomy and alveoloplasty.

A periodontal flap contains gingiva and alveolar mucosa.

Root planing refers to the removal of dental deposits from and smoothing of the root surface of a tooth; it is described as closed when performed without a flap and open when performed after flap creation.

The gingival sulcus is a normal shallow space between the marginal gingiva and the tooth. Its depth is generally 0.5 to 1 mm in cats and 1 to 5 mm in dogs, depending on the specific tooth and the size of the patient.

A pocket is a pathologically deepened gingival sulcus that occurs secondary to coronal movement of the gingival margin (pseudopocket), apical movement of the gingival attachment (periodontal pocket) or a combination of both. The clinical or absolute pocket depth is the distance from the gingival margin to the base of a pocket (measured in millimeters).

Gingival recession refers to the displacement of the gingival margin apical to the cementoenamel junction. Periodontal pockets and pseudopockets can occur together with gingival recession.

In this article, I will help you diagnose pockets and determine the optimal treatment.

Suprabony and infrabony pockets

Suprabony pockets, also referred to as supra-alveolar and supracrestal pockets, occur above the crest of alveolar bone (Figure 1). The lateral wall of the suprabony pocket consists of epithelial tissue. When the suprabony pocket is less than 5 mm in a medium or large dog, representing stage 2 periodontal disease, treatment includes the removal of supra- and subgingival plaque and calculus and closed root planing. If the 5-mm pocket represents stage 3 or 4 periodontal disease, consider extraction. Treatment may also include locally applied antibiotics. For suprabony pockets greater than 5 mm without gingival recession, coronal repositioned flap surgery can be performed by a practitioner with advanced training in periodontal surgery.

Infrabony pockets, also referred to as intra-alveolar pockets, occur when the pocket floor (epithelial attachment) is apical to the alveolar bone (Figure 1). The lateral wall will consist of epithelial tissue and bone. Radiographically, infrabony pockets appear as vertical bone loss along the root surface. However, radiographs generally cannot be used to diagnose pockets since they are soft tissue defects.

Figure 1. Illustrations of normal and abnormal gingival conditions. (Illustration by Roxy Townsend)Infrabony defects can be further classified by the number of walls remaining around the tooth-information that can help inform treatment decisions. An infrabony defect is shaped like a box without a top. The bottom of the box is the base of the pocket. One of the box's sides is the tooth root. The three remaining sides of the box are the potential walls of the defect.

There is a direct relationship between the prognosis of the therapy and the number of intact walls. Three-wall defects that have progressed to stage 3 periodontal disease (25% to 50% support loss) have the best prognosis for new attachment after advanced periodontal surgery, bone grafts and stringent home care. Two-wall defects lag behind in terms of treatment prognosis, and one- and no-wall defects carry the worst prognosis. For patients with stage 2 periodontal disease (less than 25% support loss) easier treatment options can be effective (see below).

Gingival enlargement and resultant pseudopockets

Gingival enlargement is an increase in the size or thickness of the gingiva (Figure 1). Gingival hyperplasia, a histopathologic term, is an increased number of normal cells in normal arrangement. Gingival hypertrophy is an increase in the size of individual cells. Gingival hyperplasia and hypertrophy can be accurately diagnosed only microscopically. When viewed clinically without histologic confirmation, this condition is correctly referred to as gingival enlargement.

The specific cause of gingival enlargement is unknown, but there may be a genetic predisposition in boxers, rottweilers, Great Danes, collies, Doberman pinschers, Dalmatians and golden retrievers. Cyclosporine, phenytoin and calcium channel blocker medications, including amlodipine, have also been implicated (Figure 2A). Elimination of these medications, coupled with dental scaling, polishing and removal of the enlarged gingiva (preserving at least 2 mm of attached gingiva), usually results in a cure in cases caused by medication (Figure 2B).

Figure 2A. Gingival enlargement resulting in pseudopockets. (All images courtesy of Dr. Jan Bellows)

Figure 2B. A gingivectomy surrounding the left maxillary third and fourth premolars and first molar is performed, eliminating the pseudopockets. Gingival enlargement can lead to increased pocket depths secondary to augmented gingival height versus attachment loss (Figure 3A and 3B). The resultant pseudopocket accumulates plaque and calculus, which, if left untreated, may progress to attachment loss. Surgical treatment, including gingivectomy and gingivoplasty, is performed using a scalpel blade, laser or radiosurgery to sculpt the gingiva and decrease or eliminate the pseudopockets.

Figure 3A. Gingival enlargement secondary to amlodipine.

Figure 3B. Gingival enlargement resolved after discontinuation of medication and laser-assisted gingivectomy.

What to do when you find a pocket

The goal of periodontal therapy is to decrease the size of or eliminate pockets in cases of early and moderate periodontal disease by removing subgingival plaque and calculus, using locally applied antimicrobials, performing gingivectomy, or extracting the affected teeth. Extraction is indicated when more than half of the root is not supported by the periodontium.

Subgingival cleaning: ultrasonic scaling. Bacteria-coated calculus left on the root surface contributes to the progression of periodontal disease. In order for the ultrasonic scaler to therapeutically débride a periodontal pocket, it needs to contact every part of the accessible root surface. Using ultrasonic thin periodontal tips specifically manufactured for root surface use, place the scaler tip's side parallel to the long axis of the tooth, similar to positioning a diagnostic periodontal probe. To avoid iatrogenic damage, decrease the power and increase the amount of water irrigation to remove subgingival plaque and calculus. After you've completed ultrasonic tooth scaling, use an air/water syringe to gently blow the gingival margin away from the tooth and examine the tooth surface for remaining plaque and calculus to remove (Figure 4). You can then use water from the air/water syringe to lavage unattached debris from the sulcus or pocket.

Figure 4. An air/water syringe is used to show plaque and calculus not removed during scaling and polishing.Subgingival cleaning: curette-assisted root planing. The goal of root planing is to make the root less supportive of bacterial colony formation, plaque and calculus (Figure 5). Insert the curette with the face of the blade flush against the tooth. When the instrument reaches the bottom of the pocket, the working angulation of the instrument (between 45 and 90 degrees) is established. Place the instrument against the tooth, pulling coronally and repeating the process until all subgingival calculus is removed. 

Figure 5. Subgingival root planing. Locally applied antibiotics. Applying local antibiotics is thought to reduce pocket depth by aiding in tissue shrinkage, connective tissue remodeling and soft tissue attachment. Diligent home care is essential for maintenance.

There are two locally applied antibiotic products approved for dental conditions in small animals: Clindoral (TriLogic Pharma) and Doxirobe Gel (Zoetis). In cases of early periodontal disease, the biodegradable insertion of either of these products allows for the sustained release of therapeutic levels of the antimicrobial for several weeks at the injection site. However, neither product is a substitute for scrupulous pocket débridement and subsequent home care, and neither one should be applied to unclean root surfaces. 

Clindoral is a periodontal pocket filler containing 2% clindamycin hydrochloride in a biodegrading, mucoadhesive gel matrix that releases clindamycin to the dried periodontal pocket or sulcus over a period of seven to 10 days after a single application (Figures 6A-6C). As the product warms to body temperature, it increases in viscosity two- to threefold to form a soft, pliable matrix the consistency of thick jam. Any liquid product that is part of the cleaning (e.g. fluoride, chlorhexidine) should be applied before applying Clindoral, and tooth sealants should be applied after. The pet owner should abstain from wiping or brushing the pet's teeth or giving dental treats for seven days after application.

Figure 6A. An air/water syringe is used to dry a 4-mm periodontal pocket on the distal root of a dog's right mandibular first molar.

Figure 6B. Clindoral application.

Figure 6C. The appearance of extruded medication from the pocket confirms a complete fill.Doxirobe Gel is provided in a two-syringe system. Syringe A contains the polymer delivery system: N-methyl-2-pyrrolidone and poly (D,L-lactide). Syringe B contains the active ingredient: doxycycline hyclate. Once combined, the product is a flowable mix equivalent to 8.5% doxycycline. When applied subgingivally, doxycycline is slowly released from the polymer, providing a local antimicrobial effect similar to Clindoral, particularly toward gram-negative anaerobic bacteria involved in periodontal disease. As with Clindoral, clients should avoid wiping and tooth brushing for one week.

Diode laser. Lasers may have a place in periodontal therapy. Diode laser energy transmitted through a thin fiber placed into a periodontal pocket is absorbed by the melanin and hemoglobin that are present in periodontal disease. For humans, dental protocols include the débridement of the hard side of the pocket (tooth and root surface) with ultrasonic scalers and hand instrumentation.

Measure the laser fiber to a length of 1 mm short of the pocket depth and use the energized fiber tip in light contact with a sweeping action that covers the entire epithelial lining, from near the base of the pocket upward (Figures 7A-7C and 8). Clean the fiber tip often with damp gauze to prevent the buildup of debris.

Figure 7A. A 6-mm periodontal pocket affecting a dog's left mandibular canine.

Figure 7B. Laser gingivectomy of the dog's left mandibular canine.

Figure 7C. The dog's decreased pocket depth following the laser gingivectomy.

Figure 8. Locally applied diode laser energy into a dog's 4-mm pocket.More randomized controlled clinical trials are needed to measure the benefit of using lasers as an adjunct to nonsurgical periodontal therapy.

Locally applied sealants. In human dentistry, a dental sealant is a thin, plastic coating painted on the chewing surfaces of teeth to prevent caries. In veterinary dentistry, caries are rare, so sealants are applied to help prevent periodontal disease (Figure 9). Currently, there are two commercially available veterinary dental sealants that have been clinically proven to prevent the reattachment of plaque and calculus: SANOS Dental Sealant (AllAccem) and OraVet Plaque Prevention Gel (Boehringer Ingelheim).1-3

Figure 9. Dental sealant application.

SANOS Dental Sealant has been accepted by the Veterinary Oral Health Council and is applied by a veterinary professional during the oral hygiene procedure. SANOS is a hydrophilic polymer that seals the subgingival sulcus or small pocket from the accumulation of plaque and tartar. The hydrophilic design of the sealant is uniquely engineered to attract water and allow oxygen to pass through to create an unfavorable environment for anaerobes. Reapplication is recommended at six-month intervals. Home care products are OK to use with SANOS, though withholding dental diets, dental chews, water additives and gels for seven days after a professional cleaning is recommended.

OraVet Plaque Prevention Gel is a hydrophobic wax that binds electrostatically to tooth enamel, creating a barrier that helps prevent plaqueforming bacteria from attaching. Ora- Vet is applied professionally during the oral hygiene procedure and then weekly by the client thereafter. If clients also use OraVet Dental Hygiene Chews with their dogs, they should wait two weeks after OraVet Sealant is applied, as the mechanical abrasion of the chews will remove the sealant.

In conclusion

Periodontal disease is the most common malady affecting dogs and cats. With 42 teeth in dogs and 30 in cats, you have a great opportunity to make a difference in the lives of your patients and their caregivers.

References

1. Bellows J, Carithers DS, Gross SJ. Efficacy of a barrier gel for reducing the development of plaque, calculus, and gingivitis in cats. J Vet Dent 2012;29(2):89-94.

2. Gengler WR, Kunkle BN, Romano D, et al. Evaluation of a barrier dental sealant in dogs. J Vet Dent 2005;22(3):157-159.

3. Sitzman C. Evaluation of a hydrophilic gingival dental sealant in beagle dogs. J Vet Dent 2013;30(3):150-155.