Complications of Periodontal Therapy

An estimated 85% of dogs and 75% of cats over 3 years of age display some form of periodontal disease (PD). A condition caused by bacteria present in plaque that involves any of the tooth-supporting structures (gingiva, periodontal ligament, cementum, alveolar bone), PD is considered the most common disease in companion animals.

Periodontal DiseasePlaque accumulation is responsible for development of gingivitis (inflammation of the gingiva). Bacteria present in plaque induce tissue destruction via production of cytotoxins and enzymes, and the resulting endogenous inflammatory response leads to additional destruction of tissues.^1,2 Inflammation along the periodontal space can progress to periodontitis, characterized by active destruction of the periodontal ligament and alveolar bone with pocket formation, recession, or both.³ Without treatment, the affected tooth eventually becomes mobile and is lost.

PD can also progress to endodontic disease if alveolar bone loss advances to the root apex or lateral canal.⁴ Untreated PD may also result in chronic rhinitis and ophthalmic manifestations.⁵ In dogs, there is evidence that PD may affect systemic health based on a positive correlation between the severity of PD and histopathologic changes in the kidney, myocardium, and liver.⁶ Multiple studies in people suggest an association between PD and certain systemic disorders such as diabetes mellitus, pneumonia, heart disease, and preterm birth.⁷

Periodontal treatment can be divided into 3 phases: initial, surgical (if indicated), and maintenance therapy. Initial therapy includes removal of supra- and subgingival calculus and plaque, followed by polishing. Surgical therapy is often indicated in teeth affected by end-stage PD (ie, greater than 50% attachment loss) and for periodontal pockets deeper than 4 mm. Maintenance therapy is required to prevent the recurrence of PD. The gold standard for plaque control is tooth brushing. In some cases, oral antiseptics and/or antibiotics may be indicated.

ComplicationsIn general the potential benefits of dental care outweigh the potential risks. However, as with any medical or surgical procedure, potential complications exist.

IatrogenicPeriodontal therapy involves use of a variety of instruments, some of which are sharp, hot, vibrate, or have parts that rapidly spin. Teeth are at risk of accidental mechanical injury, thermal burn, or chemical irritation.

Inappropriate use of hand or powered scalers can cause surface gouging of the enamel or cementum. Overzealous application of calculus-removing forceps can fracture teeth, especially in cats. Iatrogenic removal of enamel or cementum exposes underlying dentin that potentially compromises pulp vitality and can result in significant discomfort. Thermal damage to a tooth may also result in pulpitis or, in the worst-case scenario, pulp necrosis.

Other oral tissues including the gingiva, mucosa, palatal epithelium, tongue, and lips are also susceptible to accidental abrasion, laceration, thermal injury, and chemical irritation during routine periodontal therapy. In addition, debris or particles left in the sulcular space can induce a painful inflammatory response.

Anesthesia-RelatedGeneral anesthesia is required for dental treatment in veterinary patients.⁸ Discussion of all potential anesthetic complications is beyond the scope of this article; however, because fluids are used extensively within the mouth, a few specific complications to consider in regard to dental procedures include hypothermia⁹ and aspiration of oral debris (eg, loose calculus pieces).

Because fluids are used extensively in dental procedures (as part of ultrasonic scaling and to rinse the mouth), evaporative cooling of the patient is common; this may result in clinical hypothermia. The heavy use of fluids also increases the likelihood of pharyngeal fluid accumulation with possible pulmonary aspiration. Other oral debris such as loose calculus pieces or exfoliated teeth can also be aspirated while under general anesthesia.

BacteremiaBacteremia is a recognized sequela to dental scaling and other oral procedures and may be an endogenous source of wound infection.

Continuation/RecurrenceThe number one complication of periodontal treatment is continuation or recurrence of PD. When periodontal therapy is deficient, clinical signs may continue/reoccur and manifest as gingivitis, halitosis, or tooth mobility. In addition, an appropriate home care plan is vital to long-term success.

PreventionIatrogenicRemoval of plaque and calculus is generally performed using a combination of power and manual scaling. Operators should be properly trained in safe, effective handling.

Hand scaling: Recognizing practical limits of hand scaling is important. The sharp point of a hand scaler can gouge enamel or lacerate soft tissue if used indiscriminately. Fine instrument control is necessary to avoid causing oral soft tissue injury. Holding a hand scaler in a modified pen grasp, a finger should be rested against a nearby tooth for better stability. For subgingival debridement, only a curette (with a rounded tip) should be used, not a sharp-tipped scaler (see comparison in Figure 1).

Forceps: Care must be taken when using calculus-removing forceps: the longer forceps tip should be placed over the crown, the shorter under the calculus. If placed incorrectly or handled indiscriminately, accidental tooth fracture can occur.

Power scaling: Power scalers can damage teeth by mechanical etching or thermal heating. A few general principles apply to all types of power scalers:• Do not direct the tip at a 90° angle to the tooth surface.• Ensure adequate water spray.• Never spend more than 5 to 10 seconds at a time on one tooth.• The instrument should be grasped lightly, not tightly. Power scalers rely on vibration for most of their action and this cannot happen if the tip is pressed hard into enamel.• For supragingival scaling, use the side of a wide "beaver tail" tip and not the end (Figure 2).• For subgingival debridement, use only the thin tips specifically designed for such use (Figure 3). (A wide supragingival tip is compared to a thin subgingival tip in Figure 4.)• Avoid accidental contact with nearby cheek or tongue tissue (Figure 5).Rotary scaling, which uses 6-sided scaling burs in a high-speed hand piece, results in considerable enamel loss10 and is not recommended.

To avoid chemical irritation when using chlorhexidine, be sure the solution is dilute (0.05% to 0.12%). For polishing, consider use of a 90° oscillating prophy cup (Twist Prophy Cups; Twist2it Inc, www.twist2it.com) instead of a rotating cup to help prevent accidental winding of facial hairs into the moving part (Figure 6). As with the power scaler, do not spend more than 5 to 10 seconds at a time on any tooth.

If employing a mouth gag, do not fully open the mouth for prolonged periods or overextend the temporomandibular joint; this can result in myalgia, neuralgia, and/or trauma to the joint.

Debris in the sulcular space can be irritating. At completion of treatment, a final subgingival irrigation with saline or dilute chlorhexidine 0.12% will help remove loosened, residual plaque or calculus, as well as missed prophy paste. When subgingival material is purposely left in place (eg, Doxirobe Gel; Pfizer, www.pfizerah.com), antiinflammatory medication can help lessen irritation.

If pain is anticipated, preoperative analgesia (eg, opioid or NSAID) should be incorporated into the anesthesia plan. Regional nerve blocks using 0.5% bupivacaine should be considered to provide additional analgesia/postoperative pain relief and to reduce general anesthestic requirement.¹¹

Anesthesia-RelatedDental patient temperature monitoring is necessary, and a circulating warm water blanket and/or warm forced-air body covering is warranted. Attention should be given to adequate inflation of the endotracheal cuff and inspection/swabbing/suction of the pharynx immediately prior to anesthesia recovery. Patient positioning may be chosen based on the operator's preference, but a towel or sandbag should be placed under the patient's neck with the head tilted downward to ensure adequate drainage of saliva and irrigating fluid. If a pharyngeal pack is placed, it must be removed prior to extubation.

BacteremiaBecause a degree of bacteremia results from periodontal treatment, elective surgical procedures should not routinely be combined with treatment. In select cases of geriatric or debilitated patients where an additional anesthetic event is risky, a minor surgical procedure in conjunction with periodontal treatment may be justified. This decision should be left to the judgment of the veterinarian.

Prior to dental procedures, the patient's mouth may be lavaged with a 0.12% chlorhexidine solution to decrease amount of aerosolized bacteria and degree of bacteremia induced.¹² As a general rule, therapeutic use of antibiotics in oral surgery is indicated only in patients with local and systemic signs of established infection. Clinical judgment is important in making the diagnosis of infection and in deciding on antibiotic therapy. Refer to the American Veterinary Dental College statement on the use of antibiotics in veterinary dentistry for guidance (www.avdc.org/position-statements.html).

Continuation/RecurrencePD will continue due to residual plaque or plaque-laden calculus. Proper periodontal technique should always be employed to minimize this process. A common mistake is to place too much emphasis on supragingival calculus and not enough on subgingival plaque. To avoid missed pathology, systematic examination of the dental and soft tissues should be performed in all animals undergoing routine periodontal treatment.

The veterinarian or veterinary technician performing routine periodontal treatment should be familiar with normal anatomy and morphology in dogs and cats so as to be able to distinguish what is abnormal. Clinical examination of all teeth is combined with radiology to document and assess the degree of PD and to plan treatment.

Whole mouth radiographs using dental film (or digital sensor) are necessary for accurate evaluation and treatment planning at initial presentation; then periodically thereafter. Localized radiographs should be taken when pathology is discovered. (See Box for periodontal treatment sequence.)

It is vital that an individualized home care plan be designed and recommended. Because PD is ultimately due to plaque presence, which reforms on the tooth surface within a matter of hours, daily plaque control is just as important as professional periodontal therpy.¹³ Maintenance therapy is primarily based on tooth brushing; supplemental control is achieved through the use of oral rinses, diets, chew aids, polymer barriers, Porphyromonas bacterin, or some combination thereof.

TreatmentIatrogenicFor mild sensitivity (eg, postprocedural gingival inflammation or minor abrasion) a dispensed systemic analgesic (administered for a few days) may be sufficient.

For acute, full-thickness enamel trauma (exposed dentin), immediate application of a resin-based dentinal sealer is indicated. This will temporarily occlude the dentinal tubules and prevent entrance of bacteria and bacterial by-products into the pulp system. If the pulp remains healthy, reparative dentin will form. Periodic intraoral radiographic evaluation will be needed to assess the long-term health of the tooth.

For severe tooth damage resulting in pulp exposure, immediate endodontic therapy (vital pulp therapy or complete pulpectomy) or extraction is indicated.

Lacerations should be sutured with an absorbable suture material, ideally in a simple interrupted pattern. Swaged-on, reverse-cutting needles are recommended. Our suture material of choice for the oral cavity is 4-0 or 5-0 Monocryl (Ethicon Inc, www.ethicon.com). For more severe trauma (eg, deep laceration), surgical intervention is warranted.

When pulpal thermal damage is suspected, close monitoring will be necessary; a systemic antiinflammatory agent may be warranted. Unfortunately, a means of reliably testing pulp vitality in dogs and cats is not available. Dental pain or radiographic evidence of endodontic disease warrants extraction or endodontic therapy.

BacteremiaTypical bacteremia associated with routine periodontal treatment resolves in a relatively short period of time (ie, within 60 minutes).¹⁴ Antibiotic prophylaxis should be necessary only in geriatric or debilitated animals; patients with preexisting heart disease, systemic disease, or immunocompromise; those with prosthetic joint replacement within 2 years; when periodontal treatment is combined with elective surgery or major extractions are planned; and in patients with gross infection and chronic stomatitis.

Continuation/RecurrenceFor patients with severely advanced periodontal changes (ie, bone changes), surgical intervention may be necessary. Some patients may have medical or anatomic conditions that predispose to unfavorable periodontal management. In many cases, extraction of a severely affected tooth provides rapid improvement in local oral health and potentially increases periodontal treatment success for the remaining teeth. For advanced procedures, a pet should be referred to a specialist if the practitioner does not have the skills, knowledge, equipment, or facilities to perform treatment.¹⁵

ConclusionSuccessful treatment and control of PD requires a multidimensional approach, achieved through a combination of professional dental treatment and daily home care. Most complications associated with periodontal therapy can be anticipated and prevented.

Periodontal Treatment Sequence:Under AnesthesiaOral examinationIrrigationSupragingival calculus removalSubgingival debridementPlaque/calculus detectionPolishingDental radiographs*Sulcus irrigationChartingAftercareShort-term postoperative treatmentLong-term home careReevaluation

*At the clinician's preference, it is acceptable to perform radiographs prior to subgingival debridement. Extractions may be performed immediately after radiographs.

PERIODONTAL THERAPY • Donald E. Beebe & Steven E. Holmstrom

ResourcesAAHA Dental Care Guidelines for Dogs and Cats: www.aahanet.orgAmerican Dental Society: Membership is open to any veterinarian, dentist, hygienist, technician, or individual with an interest in veterinary dentistry (www.avds-online.org). AVDS membership includes annual subscription to the Journal of Veterinary Dentistry.Journal of Veterinary Dentistry: www.jvdonline.orgVeterinary Dental Forum: Annual continuing education meeting conducted each fall with lectures and wet labs for veterinarians and technicians, sponsored by the AVDC, ADVS, and AVD (www.veterinarydentalforum.com)