Advanced dental procedures for pets: What’s possible?

January 23, 2020

Flap surgeries, root canals and orthodontic techniques are all legitimate alternatives to extraction in many veterinary dental cases. We owe it to our clients to let them know their options.

examining dog's teeth
Dmitrii / stock.adobe.com

As veterinary practices have become more modern, sophisticated and technologically advanced, so has our ability to perform veterinary dentistry at a much higher level than previously thought possible. As veterinary professionals, we need to be fully aware of the dental treatments available and understand when to offer a referral for advanced dentistry.

In this article, we’ll cover some of the many options for advanced dental care for pets. Let’s get started.

Preparing for advanced periodontal therapy

Statistics show that periodontal disease is the most prevalent dental disease in dogs and cats. Left undiagnosed and untreated, it can progress until there is no other option but to extract affected teeth. However, when dental disease is diagnosed early, teeth can be salvaged through periodontal surgical techniques and home care, and patients can benefit over the long term by retaining important teeth for their function.

Larger and more essential teeth can be difficult to extract even when affected by significant periodontal disease, which can result in horizontal or vertical bone loss, furcation (the area between a multirooted tooth’s roots) bone loss, and tooth mobility due to loss of attachment. When we examine teeth and the surrounding bone through clinical observation and full-mouth dental radiographs, we must assess the true extent of the pathology, noting bone loss, attachment loss, and tooth mobility. Radiographs and clinical findings help the practitioner determine which teeth are good candidates for therapy, and when extraction is the best option. We can evaluate a tooth on a root-by-root basis as well as examine individual sides of each tooth root. A tooth with significant bone loss (>50%) on the root’s surface may have a poor prognosis even with advanced therapy, especially if the bone loss is around the root, or what’s called a four-walled defect.1,2 If the bone is lost from the furcation, this reduces the chances for success even further.1,2

Evaluating total attachment loss. Total attachment loss is the sum of the measurement of any gingival recession on the root’s surface, as well as any pocket depth beyond that recession. If gingival recession is not present, then it’s just the measurement of any periodontal pocket depth beyond what may be considered a normal sulcular depth for that specific tooth in that particular pet’s mouth. Normal sulcular depth ranges from 0 to 1 mm; however, "normal" can differ depending on the size of the animal, size of the tooth and length of the tooth root.

A periodontal probe with clearly marked 1-mm increments is used to measure from the marginal gingival edge to the bottom of the sulcus or periodontal pocket if there is attachment loss.1,2 The bottom of the sulcus is attached to the tooth’s surface at or very near the cementoenamel junction.1 Attachment loss at this point creates a periodontal pocket and a pathological process.

Using a gentle hand and holding the periodontal probe in line with the vertical axis of the tooth, the clinician walks the probe around the tooth’s structure and takes measurements in four to six places around each tooth root. Whenever these measurements are greater than what would be considered normal for that particular tooth, they’re recorded on the patient’s dental chart.1 Note that conditions such as gingival enlargement can create a false pocket depth and not actual attachment loss, so excess gingival tissue must be measured carefully; take note whether the bottom of the sulcus is at the cementoenamel junction to determine the extent of attachment on these teeth.1

If the combined loss of bone and soft tissue attachment is less than 50% and the furcation loss of bone is less than halfway through, it may be possible to “save” important or strategic teeth through advanced periodontal surgical techniques, frequent follow-up care (possibly under anesthesia) and a commitment to daily home care by the client.

For a periodontal pocket depth greater than 5 mm, it’s recommended that open root planing and subgingival curettage be performed with the use of flap surgery to facilitate visualization of the bony defect and exposed root surface (more on flap surgery to come). Open root planing allows the practitioner to treat the area to the best of her ability to get the best possible outcome from periodontal therapy.1

Obtaining dental radiographs. Besides measuring attachment loss, the veterinary team must obtain radiographs to assess the extent of any suspected bone loss. Evaluating a full set of intraoral dental radiographs will help determine the success of any proposed procedure and also provide a baseline for monitoring treatment progress. If your veterinary practice cannot obtain those dental radiographs and the client is interested in advanced dental care and saving teeth rather than extraction, consider a referral from the onset—it may be in the best interest of the patient.

Advanced periodontal flap surgeries

Techniques to perform flap surgeries are fully described in several dental textbooks and can be learned at labs taught by veterinary dentists on the subject. However, if surgical procedures that are beyond the practitioner’s skill level are indicated, referral may be the best option.

Apically repositioned flap. This technique can be used to help the attached gingiva lie over any remaining alveolar bone; it requires at least 2 mm of gingiva to extend toward the crown.1 This surgery moves the gingiva down onto the root surface after the area is cleaned of unhealthy bone, granulation tissue and debris; then the area is allowed to heal.3 This procedure can be performed on mandibular incisors to allow for a reduction in periodontal pocket depths, easier cleaning of furcation exposure areas on multirooted teeth, and daily cleaning by the client.3

Contraindications include more than 50% bone loss (especially on a four-walled defect), grade 3 tooth mobility and the presence of less than 2 mm attached gingiva before surgery.1

Laterally positioned (pedicle) flap. When the root surface of a single tooth is exposed significantly due to a cleft of bone and soft tissue loss that extends to or near the mucogingival line, a laterally sliding flap surgery may be indicated.1 This procedure requires carefully planned and executed vertical releasing incisions, as well as the creation of a donor flap that’s moved laterally over the area and sutured.1 The goal is to partially cover the exposed root surface and allow for at least 2 mm of attached gingiva to help preserve the health of this particular tooth; the area of exposed tissue from the donor site will heal by second intention.1,2

Contraindications for this procedure include tooth mobility due to loss of bone on more than one wall of the alveolar socket, furcation bone loss and lack of commitment on the client’s part to daily home care and more frequent follow-up professional dental care.1

Free gingival graft. This technique is indicated in specific individual teeth with a cleft-like defect that is free of endodontic disease and where tooth mobility is not present.2 A gingival graft is obtained from a donor site separate from the site to be treated, often the buccal surface of attached gingiva over the maxillary canine—this site offers the largest expanse of tissue.2 The donor graft is harvested carefully using a template, employing a careful technique to avoid damage to the periosteum.2 The donor tissue is then carefully grafted over the recipient site using specific surgical techniques.2

This procedure is contraindicated if endodontic disease is present and not treated first.2 Concurrent periodontal disease must also be treated and controlled; if there is tooth mobility, this technique is unlikely to have a good outcome.2 Success will also depend on the client’s willingness to comply with daily recommended home care and follow-up veterinary treatment.2

Guided tissue regeneration. The goal of guided tissue regeneration is to help facilitate the development of cementum on the root’s surfaces and the regeneration of healthy periodontal attachments.1 Once the tooth root surface has been cleaned and treated, barrier membranes that are either absorbable or nonabsorbable are positioned to prevent granulation tissue from invading the area. The goal is to encourage bone induction behind vertical bone walls and periodontal ligament cells to develop in areas where they’ve been destroyed by periodontal disease.1

The use of bone inductive materials can assist in such procedures where significant bone has been lost in two- and three-walled bony defects and areas of class 2 furcation bone loss in multirooted teeth.

Endodontics

Endodontics is the dental discipline that treats disease involving the internal tissues of a tooth.1 These inner tissues are highly neurovascular and susceptible to trauma, which can cause significant inflammation and lead to irreversible damage, including tissue necrosis and death.1,2 Concussive injury to a tooth can cause the pulp to bleed inside the tooth into the dentinal tubules or expose the pulp to the oral cavity, as in the case of a complicated crown or crown-root fracture.1 Other causes of endodontic disease are near-pulp exposures such as in an uncomplicated tooth fracture into the porous dentinal tubules, a carious lesion or cavity, severe abrasion or attrition, or bacterial invasion through the animal’s bloodstream through the apical delta into the root canal and pulp chamber of the tooth.1,2

Root canal procedures are performed to retain important strategic teeth in their alveolar bony sockets to maintain function. The vital or once-vital endodontic tissue is removed and replaced with an inert filling material; the access and fracture sites, if applicable, are also filled with a composite material.1,2 The tooth is not restored to its original height because the weakened tooth would be more prone to further damage or fracture. Annual monitoring is recommended after root canal treatment, and dental radiographs should be obtained to evaluate the continued success or failure of the procedure.1,2

Restoration of teeth affected with carious lesions

True carious lesions are not common in dogs and especially not common in cats; however, if they are found, they can be restored with cavity preparation and restoration material after careful evaluation of dental radiographs.1 Some carious lesions involve the pulp and should not be restored without conventional endodontics.1 If concurrent periodontal disease is also present, the prognosis for these teeth may be significantly worse.1

Restoration of enamel defects

Enamel defects can be acquired from tooth wear due to abrasion or attrition or a congenital condition that prevents enamel from forming correctly before adult tooth eruption.4 Trauma, infection, hypocalcemia or the use of certain drugs during the enamel-forming period can also cause defects or malformations on the enamel of unerupted permanent dentition.5

Amelogenesis imperfecta is an inherited defect that is fairly rare in dogs and also rare in people. It is most common in species located in remote areas where the genetic pool is less diverse.5 Hypoplastic, hypomaturation and hypocalcification are the three types of amelogenesis imperfecta.5 Enamel hypocalcification leaves the enamel very fragile even though the depth is within normal limits; it has failed to undergo mineralization and is easily removed from the dentin below it.5

The goal of enamel restoration is to prevent any further destruction of the surrounding enamel and to protect the pulp and dentin from damage due to changes in temperature, bacterial invasion, and further wear or loss of enamel substance.1 Occasionally in the case of attrition, we will choose to restore an important tooth, such as a canine tooth, and extract a less important tooth, such as an incisor, if these two teeth are rubbing on each other and causing a lesion or enamel defect.4 If the defect is caused by forces other than another tooth, the source of that wear must be removed to prevent further wear and loss of the restorative material on that tooth.4

A flowable type of composite can be used to repair areas of enamel hypoplasia or enamel defects on the crown.4 First, the enamel defect must be prepared to accept and retain the composite material, which will help restore the tooth to a more normal contour and function.2,4 Preparation entails the debridement of diseased or damaged enamel and contouring the edges with a pear-shaped bur used in a high-speed handpiece, cooled with water spray.4 An excavator is used to prepare the area further.4 An acid etchant is then used to remove the smear layer from the exposed dentin and create an environment where the restoration will bond more effectively through micromechanical interlocking.1,4

An unfilled resin—a bonding agent that helps the flowable composite attach more readily—is then light-cured onto the surface of the prepared defect.4 Composite is flowed into the defect and allowed to overfill the area slightly, then cured with a special dental curing light and finished with a fine diamond bur or polishing disks, so the edges of the composite are not detectable when investigated with the tip of a shepherd’s hook exporer.4

Enamel restoration may help increase the durability of the tooth. The client should be informed of the possibility of lost restorations, the likelihood of further treatment and the necessity of preventing the habit or behavior that caused the defect (if applicable) to avoid further damage to these teeth.4

Orthodontics

Orthodontics deals with the correction of malocclusions or abnormally positioned teeth that are causing trauma to teeth or soft tissues. Trauma results in either tooth-on-tooth wear and damage (attrition) or tooth-on-soft tissue trauma. These ongoing traumas cause patient pain and can lead to tooth damage and endodontic disease.1 It’s important to become familiar with the basic skull types, how these occlusions are evaluated and categorized, and what constitutes a comfortable, pain-free occlusion for our patients.

Orthodontic abnormalities should be recognized by the general practitioner early on in the pet’s life. During the primary, mixed or early eruption of permanent dentition phases, the teeth should be carefully evaluated and any abnormalities noted. Persistent primary or retained deciduous teeth can further exacerbate occlusion problems.

At-risk breeds are those with jaw relationships outside the normal limits associated with mesocephalic skull types. These dogs and cats should be monitored closely for any signs of malocclusion, and early intervention through interceptive orthodontics should be performed if indicated. If the practitioner diagnoses a malocclusion, referral to a veterinary dentist may be the best option.

Common malocclusions in dogs and cats are:

Lingually displaced mandibular canines (MAL/LV). When this occurs, the cusps of the canines are tipped too far lingually and may cause soft tissue trauma to the hard palate.1 Occasionally this condition occurs due to the lack of space, or diastema, between the lateral maxillary incisors and the maxillary canine teeth either bilaterally or unilaterally.

Rostral crossbite (MAL/CB/R). In this condition, some or all of the mandibular incisors are positioned in front of or rostral to the maxillary incisors rather than the preferred scissor bite.1

Caudal crossbite (MAL/CB/C). When one or more of the mandibular premolars or molars occlude buccally to the maxillary teeth above them, a caudal crossbite has occurred. A more extreme example is when the maxillary fourth premolar occludes palatal to the first molar of the mandible on that same side of the mouth.1

Level bite (MAL1). In this condition, the maxillary and mandibular incisors occlude right on top of each other, causing attrition to the crown cusps over time.1 A malocclusion could also occur when the maxillary premolars occlude with the mandibular premolars on the same side of the mouth, which can cause potential problems with mouth closure and pain.1

Mesioversion of maxillary canine teeth (MAL/MV). In these patients, the maxillary canine teeth are tipped too far forward, causing a reduction in the diastema between the maxillary third premolar and the maxillary canine tooth on that side.1 The crown tip can also cause trauma to the patient’s lip.

Orthodontic movement should not be undertaken by untrained professionals, but a basic understanding of occlusion can assist veterinarians in making recommendations for treatment rather than disregarding these conditions as unavoidable and untreatable. Early and careful intervention may be required even when only primary dentition is involved in preventing more complicated and costly orthodontic intervention later on in life.

Summary

Keeping the patient’s best interests in mind helps veterinary teams make the proper observations, and then recommendations, for advanced dental treatment and procedures. Developing a working relationship with a referral veterinary dentist can be very helpful as advice and insights are exchanged via consultations on specific cases. Having a financial quote ready for clients who choose referral for more advanced treatment options will also be important when they need to make treatment decisions. Open communication with clients increases their understanding of your findings and diagnoses and helps them feel more comfortable with your recommendations and referral.

References

1. Bellows J. Small animal dental equipment, materials, and techniques: A primer. Ames, IA: Blackwell, 2004;142-157, 175-239, 263, 296.

2. Holmstrom SE, Frost P, Eisner ER. Veterinary dental techniques for the small animal practitioner, 3rd ed. Philadelphia: Elsevier; 2004;262-274, 340-494.

3. Beckman B. Mandibular incisor apically repositioned flap in the dog. J Vet Dent 2003;20(4):245-249.

4. Taney KG, Smith MM. Composite restoration of enamel defects. J Vet Dent 2007;24(2):130-134.

5. Mannerfelt T, Lindgren I. Enamel defects in standard poodle dogs in Sweden. J Vet Dent 2009;26:213-215.

Benita Altier LVT, VTS (dentistry), is the owner of Pawsitive Dental Education in Easton, Washington, and a frequent speaker for the Fetch dvm360 conferences.