Periodontal disease

Paul Q. Mitchell, DVM, DAVDC
Veterinary Dental Services, Boxborough, MA
Posted on 2017-11-14 in Dentistry  

The extent of periodontal disease encountered in veterinary patients can vary from patient to patient and even from tooth to tooth in the same patient. From minimal inflammation and no attachment loss in Stage 1 Periodontal Disease to the beginnings of attachment loss (up to 25%) in Stage 2, then deeper pockets (up to 50% attachment loss in Stage 3) and even compromised teeth (greater than 50% loss) in Stage 4, the clinician must be able to tailor the treatment to the problem. Basic steps of professional dental cleaning must sometimes be supplemented with additional periodontal management.

Therapy goals

When looking at periodontal disease, therapy is determined by a number of factors, such as the stage of the disease, the desired outcome and the motivation of the pet owner. There are several goals to set, including removal of all debris or biofilm (plaque, calculus), keeping the maximum amount of attached gingiva, minimizing attachment loss and minimizing the pocket depth.¹ Certainly, all foreign material, from bacteria to desquamated cells must be removed from the tooth surfaces and pockets in order to attain healing. Since the attached gingiva is the first line of defense against bacteria, a minimum of 2-3 mm is necessary to protect underlying tissues, as the looser alveolar mucosa doesn’t afford that protection. The inability to halt attachment loss will eventually lead to tooth loss. Minimizing pocket depth is related to attachment loss, but is a more specific parameter, because the pocket depth in itself directly affects the ability for effective home care and maintenance, and deeper pockets can harbor more virulent strains of bacteria. There are even times where excessive gingiva will be removed to decrease pocket depth (hyperplastic gingiva) or the gingiva will be sutured further down the root (apically repositioned flap) for the same effect. Attachment loss without pocket formation occurs when gingival tissue and bone is lost at the same time, exposing the roots and even furcation areas.

The ability to take intraoral radiographs is essential, in order to determine the extent and characteristics of bone loss.² With recession of gingiva and bone across several roots and/or teeth, a horizontal bone loss pattern will often result in exposed roots. With a deeper osseous loss down one root surface, an infrabony pocket may result from the vertical bone loss, and specific therapy may be needed to address that specific defect. These deeper pockets are more difficult to treat and maintain, and anaerobic infections may persist.

Periodontal therapy

Periodontal therapy initially concerns itself with removing all plaque, calculus, and debris possible. This is of particular importance if there is any attachment loss or pocket formation because the surfaces must be thoroughly cleaned to help remove the destructive action of the bacteria and moderate the host response as well. Advanced procedures must be undertaken with commitment on the part of the owner as well because regular home care and frequents follow-up visits will be important

Supportive care

Additional care beyond the periodontal work is often necessary to maximize the outcome. Assistance with various antimicrobial agents can help the patient fight off the bacterial onslaught, by using everything from oral rinses and gels to medically appropriate prescriptions of systemic oral antibiotics. Even pain management must be considered because the conditions alone can be painful, and any surgical procedures must be covered as well.

Root planing/ subgingival curettage

This is by far the most important aspect of periodontal therapy.³ If the debris is not thoroughly removed from the pocket depths, the disease will remain and intensify. The rounded tip of the curette, and it’s rounded back, makes it ideal for subgingival therapy, as opposed to the sharp tip and back of a hand scaler. Certain ultrasonic scalers are modified for subgingival treatments, but most are not. If root surfaces are exposed, or if the pocket depth is less than five mm, closed root planing and subgingival curettage may be performed. Using a curette subgingivally with overlapping strokes in horizontal, vertical and oblique directions, root planing removes calculus, debris, and necrotic cementum to provide a clean, smooth surface. The curette can also be angled slightly to engage the gingival surface for removal of diseased or microorganism-infiltrated tissues. When pocket depth exceeds 5 mm, or another pathology exists, more invasive procedures are warranted.

Perioceutic therapy

In moderate pockets of up to 5 mm in depth (and generally deeper than 2 mm), once the area is debrided, placement of a local perioceutic gel containing doxycycline Doxirobe gel (doxycycline hyclate) can not only provide a direct antibacterial affect against any remaining bacteria, but the anticollagenase activity can help “rejuvenate” the soft tissue of the pocket.⁴ Doxirobe™ Gel is not for use in dogs under one year of age because the use of tetracycline during tooth development has been associated with permanent discoloring of teeth. Do not use in pregnant bitches, as the use of the product in breeding dogs has not been evaluated. The combination of the cleaning and therapy can often help reduce the pocket depth in moderate situations.

The two-syringe system is easily used but requires some practice. When initially mixing the compounds, make sure the syringes are secure before mixing (100 passes). Once mixed, the material should be placed in syringe A (place on end to get the most gel into syringe A before detaching), and a blunt tipped cannula placed. The tip of the cannula is gently placed to the depth of the treated pocket, and the material is slowly inserted into the pocket, until a small amount extrudes from underneath the gingival edge. By using light digital pressure on top of the gum, and by gently scraping the cannula tip on the tooth surface, the cannula can be removed without taking the gel with it.

The gel firms up on its own within a minute or two, or a drop of water can be placed on the material to speed up the process. Once firm, the visible material should be gently packed into the pocket, using an instrument such as a W-3, or beaver tail instrument. The owner should be instructed not to brush for about a week in the region (gels and solutions are recommended), nor to pick at the ridge of material that may become visible (light yellow-brown). The material is biodegradable and does not need removal.

Open root planing – Gingival flap

When pocket depths exceed 4 mm but with minimal bone loss or diseased soft tissue that needs removal, a simple flap allows access and improved visibility for open curettage and root planing. Insert the scalpel blade into the sulcus and following the scalloped contour severs the epithelial attachment. For large areas requiring treatment, vertical-releasing incisions can be made at the mesial and distal ends of the initial incision (at line angles of adjacent teeth). Using periosteal elevator, the gingiva is reflected to expose the root surfaces. A polishing of the root surfaces and irrigation with dilute chlorhexidine follows thorough root planing and subgingival curettage. After repositioning the flap, sometimes further apically down the roots, it is sutured interdentally with absorbable, interrupted sutures. While this procedure is most commonly performed on facial and lingual surfaces, deep pockets on the palatal aspect of the maxillary canine teeth can be exposed using a similar technique for treatment.

Guided tissue regeneration

In an infrabony defect, where the attachment loss has occurred down the surface of a tooth, forming a deep pocket in between the root and alveolar bone, inadequate therapy can lead to even further attachment, and even tooth, loss. Guided tissue regeneration (GTR) in dentistry normally deals with the reestablishment and regeneration of periodontal tissues lost due to disease or injury.⁵ Tissue regeneration has been demonstrated with alveolar bone, cementum, and the periodontal ligament in specific situation with specific types of therapy. Typically, the soft tissues (gingival epithelium, gingival connective tissue) will grow back into a defect faster than the more important supportive tissues of the periodontium (alveolar bone, periodontal ligament).

By placing a barrier between the instrumented root surface and the gingival flap, it can act as a deterrent to exclude the gingival epithelium or gingival connective tissue from populating the root structure. This barrier then provides an area for the progenitor cells of the periodontal ligament and/or alveolar bone to have free access for migration. Bone development being slower than the soft tissues of the periodontal ligament, it is hoped that it should develop prior to bony incursion. It is generally believed that periodontal cells have the greatest potential to promote new attachment, but that bone also plays a significant role.

While some barriers are actual membranes, bulk material can also be placed to keep the soft tissue out. When a substance that promotes osseous growth is placed, alveolar bone stands a better chance of filling the defect. There are even products that stimulate periodontal ligament re-growth. An essential key to such a procedure is adequate exposure and debridement of the area. A gingival flap is necessary to allow for thorough curettage of all material in the infrabony pocket in between the tooth and root, including the removal of any granulation tissue. Once healthy bone and tooth surfaces are clean, the bio-synthetic glass particulate matter is packed into the defect, and the gingival closed over it.

Post operatively vigorous home care and plaque control is essential. Antibiotics for up to three weeks post surgically are generally recommended. Doxycycline is considered a good choice in human medicine because of its antibacterial and anticollagenolytic effects, thus aiding to stabilize collagen locally.⁶ Non-absorbable membranes are normally removed one to nine months following surgery. Materials such as Consil do not need removal.

Home care is one area that the entire staff can play an important role in. Client education about the proper methods and materials for dental hygiene is crucial to the process. Staff members should be well-versed in available home care products and techniques, so they aid in demonstrations for the pet owner. Client education can start an a very early stage, introducing new puppy and kitten owners to the concept of brushing as part of a regular grooming and hygiene program. Some pets may be difficult to treat, and the risk of injury to the owner should not be assessed in recommending home care. It is important to make sure from the start that the commitment is there for the advanced procedures.

Equipment

Many standard pieces of equipment and supplies can be used, including scalpel blades (15C works well), scissors (sharp/sharp for gingival remodeling), and sutures (usually absorbable, from 3-0 to 5-0). It is important to other equipment as well for unique oral situations. Full evaluation is not possible without the use of a periodontal probe/explorer to ascertain pocket depths, and intraoral radiography is essential to get a complete picture of the situation, whether there is periodontal bone loss or for pre-extraction (and post-) radiographs. Other essential tools will include periodontal curettes for scaling root surfaces, periosteal elevators (Molt No. 2 or No.4) for elevating gingiva, good elevators (winged elevators are especially helpful), and some means of sectioning teeth.

Refining your skills

Periodontal surgery. While most practitioners provide dental services to their patients, too seldom is the gingiva actually cut to provide sufficient exposure for adequate treatment. Opening gingival flaps takes little additional skill, just the ability to know where to make the flap and proper tissue handling technique. In pockets less than 5mm, a periodontal curette, with its round toe and rounded back, is very useful for closed root planing and subgingival curettage where no flap is needed. Basically, anytime a periodontal pocket is deeper than 5 mm, the area must be exposed for adequate cleaning. With the periosteal elevator, an envelope flap can be made by lifting the gingiva directly over the defect, and extending it 1-2 teeth on either side to provide enough exposure. This can stretch the tissue out significantly if the pocket is deep, or the area is too wide. Therefore, a flap can be created by making diverging incisions mesially and distally to the defect, through the attached gingiva past the mucogingival line into the alveolar mucosa. The periosteal elevator is then used to lift the flap off the alveolar bone, providing access to the site. Sufficient elevation should be done for adequate exposure, but don’t expose any more bone than is necessary.

Once the site is laid open, every effort must be made to clean out all debris and granulation tissue from the pocket, particularly in pockets that extend down the root of the tooth, in between the tooth and alveolar bone (infrabony pocket – vertical bone loss). Once cleaned, material such as Consil™ (Nutramax Labs, Baltimore, MD) can be used to help promote osseous healing and discourage soft tissue growth into the area. This form of therapy, guided tissue regeneration, can be of particular importance with deep pockets at the palatal aspect of maxillary canines, and with deep infrabony pockets involving the lower first molar that can compromise mandibular strength. While the lower first molar defects can often be exposed using standard releasing incision flaps, the deep palatal pockets provide additional challenges. It is essential in this area to design a flap and plan sutures that will bring the gingival margins snugly against the tooth, to protect the materials in the pocket. Mesial and distal releasing incisions can be made extending out from the canine towards the adjacent teeth, on the gingival papillae. Exposure with this method can be somewhat limited, like an envelope flap, and closure involves using a sling suture technique, running the suture in a semi-circle pattern within the palatal mucosa from a mesial to distal direction, exiting distal to the canine and re-entering near the same site, reversing the semi-circle pattern to exit mesial to the tooth, and tying off the two ends, tightening the flap against the tooth. Incisions made directly into the palatal mucosa not only can cut the palatine artery, but make a flap that is more difficult to hold against the canine.

One alternate method is making a crescent-shaped flap in the palatal mucosa, extending from a point just mesial to the canine in the incisor-canine interdental space, and running medial to the canine to a point just distal to it. When the flap is elevated, there will be hemorrhage from the rostral severing of the palatine artery, but it can be tied off at that extent and preserved within the flap itself. Once elevated, good exposure allows for thorough cleaning of the infrabony pocket, though care must be taken to avoid puncturing the remaining alveolar bone separating the pocket from the nasal cavity (oronasal fistulation), else the tooth would have to be extracted. Once the pocket is cleaned and filled, simple interrupted sutures can hold the crescent flap in place. If some gaps appear, a small amount of the mesial extent of the flap can be trimmed, to bring the gingival margin closer to the tooth. Sutures can be placed to join the cut edge of the flap back to the palatal mucosa, as long as no tension is placed on the flap that would cause it to pull away from the tooth. A small gap between the cut edge of the flap and the remaining palatal mucosa will typically heal without complication.

In some areas there will be horizontal bone loss and suprabony pockets (bone loss occurs at same level of attachment loss but no defect in between the tooth and alveolar pocket). Once the area is exposed, all root surfaces areas should be thoroughly cleaned using curettes. In some cases, if the bone loss includes interdental spaces, the flap can be sutured in place so the gingival margin is actually placed further down the root than originally positioned (apically repositioned flap). This can help minimize the pocket depth, though the actual level of attachment is still the same, just more root structure is left exposed. These sites are not amenable to osseopromotive products.

References

1. Lobprise, H.B.: Complicated periodontal disease. Clin Tech in Small Anim Pract. 15(4): 197-203; 2000.
2. Robinson, J. Gorrel, C. Oral examination and radiography. Manual of Small Animal Dentistry (D.A. Crossley, S. Penman, eds.). BSAVA, Gloucestershire, UK. 1995; pp 35.
3. Wiggs, R.B., Lobprise, H.B.: Periodontology. Veterinary Dentistry – Principles and Practice (R.B. Wiggs, H.B. Lobprise, eds.) Lippincott-Raven, Philadelphia, PA., 1997; pp 186-231.
4. Cleland, W.P.Jr.: Non-surgical periodontal therapy. Clin Tech in Small Anim Pract. 15(4): 221-225; 2000.
5. Wiggs RB, et al. Oral and periodontal tissue. Maintenance, augmentation, rejuvenation, and regeneration. Vet Clin. North Am. (Small Anim. Pract.) 28(5); 1165-1188; 1998.
6. Jolkovsky DL, Ciancio SG. Chemotherapuetic Agents in the Treatment of Periodontal Disease. In: Carranza’s Clinical Periodontology, 9th ed. eds. Newman MG, Takei HH, Carranza FA. WB Saunders, Philadelphia, PA; 2002: 677, 682.