World Small Animal Veterinary Association Global Dental Guidelines.

Abstract

Dental problems are some of the most common encountered in small animal primary care practice, yet dental training at veterinary universities is often incomplete and typically provided by those without board certification. The WSAVA Dental Guidelines Committee has endeavoured to provide a written set of guidelines for dental care in companion animal patients (Niemiec et al, 2020, https://doi.org/10.1111/jsap.13132). The following article summarize the main points for primary care practitioners to highlight the full-scale guidelines. In order to provide gold standard orofacial care, there is need for in-depth anatomic knowledge of the mouth and head along with anaesthetic and pain relief techniques for those facial structures. The complete guidelines contain detailed stepwise information covering anatomy, physiology, anaesthetic concerns, pain management, common oro-dental pathology, and practical procedural descriptions from examination through treatment. Hands-on training in common dental procedures is highly recommended and available in continuing education courses in many countries. Quality of life must be considered in the context of pain, infection and biological stress in order to assess the effects these conditions have on our patients. Interpreting behavioural signals of oral pain can be complex (Le Bars et al. 2001), and most animals continue to eat despite what is assumed to be debilitating dental pain. Untreated dental disease can lead to chronic inflammation and infection of the oral tissues, along with potential systemic inflammatory damage. Compiled by a multidisciplinary committee of specialists within their respective fields, the complete WSAVA Dental Guidelines aim to provide general practitioners around the globe with practical peer reviewed information to assist in furthering knowledge and competency in all areas of oral and dental care. A complete oral examination must be performed under general anaesthesia and is comprised of a thorough clinical examination ideally combined with dental radiographs. The clinical examination includes visual inspection of all anatomic structures of the entire head and the oral cavity and examination of occlusion. Exploration of the dental crowns with a dental explorer for fractures, enamel defects, and tooth resorption as well as examination of the gingiva and periodontal attachment with a periodontal probe to detect evidence of periodontal disease such as periodontal pockets or gingival recession (Huffman 2010) is recommended. The results are recorded on a species-appropriate dental chart (Fig 1). Oral and maxillofacial disorders require general anaesthesia for examination and appropriate treatment. Therefore, anaesthesia and pain management are crucial areas of veterinary dentistry. “Anaesthesia-free” or “non-anaesthesia” dentistry is not only unacceptable from the welfare point of view but also poses a risk to the operator and the patient. Performing dental procedures without anaesthesia is potentially stressful as well as harmful to the patient, and the benefits are purely cosmetic and misleading. As many veterinarians and owners falsely believe calculus deposition drives the need for dental therapy, removing surface evidence of disease without thoroughly diagnosing or treating subgingival disease may delay effective therapy for painful and infectious disease. In addition, accurate diagnosis of type and severity of disease (which requires periodontal probing and dental radiology) requires general anaesthesia. Anaesthesia-free dentistry ultimately results in the risk of patients suffering from chronic pain and infection unnecessarily. The Association of Veterinary Anaesthetists (2015) has published a checklist for preparation of anaesthesia for dental patients that can be easily implemented in general practice. Endotracheal intubation, anaesthetic monitoring and administration of fluids are part of best practice and should prevent most complications. The choice of fluids will be based on each patient's needs and requirements. Spring loaded mouth gags should no longer be used, and the use of non-spring loaded mouth gags is discouraged due to post-anaesthetic blindness following oral procedures in cats (Stiles et al. 2012, de Miguel Garcia et al. 2013). Pain assessment should be part of every physical examination. An analgesic plan including a multimodal approach should be in place during the perioperative period and for several days to a week after hospital discharge. Local and regional anaesthetic techniques for the oral cavity (dental blocks) are specifically indicated when there is pain and inflammation (Snyder & Snyder 2013). Local anaesthetic techniques require simple, low-cost materials such as disposable syringes, 27-G or 25-G needles; administration techniques can be viewed online (Faculté de médecine vétérinaire de l'Université de Montréal 2016a, 2016b, 2016c, 2016d). Dental radiographs are essential for diagnosis of lesions that are not obvious to the naked eye. They are invaluable in treatment planning and may change therapeutic plan enough to avoid iatrogenic complications such as retained roots and jaw fractures. The most common dental procedures (diagnostic, prophylactic and surgical) cannot be properly performed without access to appropriate dental radiographic equipment, which is considered essential by the WSAVA for all tier two and three countries. Periodontal disease is a multifactorial condition leading to multiple negative local and systemic effects. Current studies report that 90% dogs suffer from this condition by 1 year of age (Fernandes et al. 2012, Queck et al. 2018) and 70% cats have some form of periodontal disease by the time they are 3 years old (Wiggs & Lobprise 1997a, Lund et al. 1999). Current understanding suggests a genetic predisposition to periodontal disease (Hoffmann & Gaengler 1996, O'Neill et al. 2013, 2019a, 2019b, Marshall et al. 2014, Wallis et al. 2018, Wallis et al. 2019). Small and toy breed dogs are known to be particularly susceptible to periodontal disease (Hoffmann & Gaengler 1996, Hamp et al. 1997, Bauer et al. 2018, O'Neill et al. 2019a, 2019b, Wallis et al. 2019). The main aetiologic agent is bacterial plaque, which is a biofilm that protects bacteria from the host immune system and antimicrobials (Quirynen et al. 2006). It forms within 24 hours and so home care is a critical part of periodontal therapy (Boyce et al. 1995, Wiggs & Lobprise 1997a, 1997b). If plaque is not removed, it will become calcified into calculus. Previously it was believed that calculus was the cause of periodontal disease but more recent research has found that calculus itself is not pathogenic, although it is an irritant and aids plaque retention (Hinrichs 2006, Niemiec 2008b). The plaque/calculus on the supragingival area (i.e. crown) of the teeth does not cause periodontal disease. It is the subgingival plaque that initiates subgingival plaque (under the gingival margin) that initiates the inflammatory cascade that results in periodontal tissue destruction in susceptible individuals (Nisengard et al. 2006). The inflammation produced by subgingival bacteria and the host response damages the soft tissue attachment of the tooth and decreases the bony support of the teeth via osteoclastic activity (Nisingard et al. 2006). Therefore, to be effective, therapeutic and preventive measures must remove plaque at and below the gumline. Periodontal disease can eventually result in tooth loss (Ramseier et al. 2008b) and problems both locally and systemically. Locally, unchecked periodontal disease can lead to secondary lesions such as oronasal fistulae (Fig 2), pathologic mandibular fractures (Fig 3), eye loss/blindness, root canal infections caused by periodontal loss that reaches the apex and osteomyelitis/osteonecrosis (Ramsey et al. 1996, Mulligan et al. 1998, Marretta & Smith 2005, Snyder et al. 1996, van de Wetering 2005, Anthony et al. 2010, DeBowes 2010, Niemiec 2013a, Peralta et al. 2015, Varughese et al. 2015). Although more research is needed, correlations between periodontal disease and systemic disease are mounting, and include negative effects on the heart, kidneys, and liver (Taboada & Meyer 1989, DeBowes et al. 1996, Pavlica et al. 2008, Glickman et al. 2009, O'Neill et al. 2013, Finch et al. 2016, Trevejo et al. 2016). Accurate diagnosis of periodontal disease requires general anaesthesia, but early clinical signs include erythema, oedema and, possibly gingival bleeding upon chewing or during tactile examination (Meitner et al. 2016). The aim of all forms of periodontal therapy is removal and control of plaque. In particular, the marginal and subgingival plaque must be completely removed to provide effective care. Even though calculus does not cause periodontal disease, its removal is important because it provides a rough surface for more rapid plaque attachment. Periodontal therapy consists of four components depending on the level of disease: professional dental cleanings, periodontal surgery and extraction when indicated, and home care (Bellows 2010a, Niemiec 2008c; Table 1). A professional dental cleaning consists of supra and subgingival scaling, polishing, sulcal lavage, as well as oral examination and charting, all of which require general anaesthesia (Huffman 2010, Holmstrom et al. 1998, Niemiec 2003, Colmery 2005, Holmstrom et al. 2013, Niemiec 2013a). Dental radiographs are essential to fully evaluate for dental disease (Verstraete et al. 1998a, 1998b). Regular effective plaque reduction is the key to long-term management of periodontal disease. Ideally, this is performed daily because plaque forms within 24 hours (Wiggs & Lobprise 1997a) and will begin to calcify into calculus (tartar) as early as 4 hours after it starts to form (Tibbitts & Kashiwa 1970). Further, Watanabe et al. 2016 showed that without homecare, bacterial counts return to pre-scaling levels in just 1 week. Every other day plaque reduction is considered the minimum for patients in good oral health (Tromp et al. 1986). Homecare consists of both active (toothbrushing and antiseptic rinses) and passive (diets and treats) measures. Golden et al. (1982) reported that 10% of dogs had a fractured tooth with direct pulp exposure and it is estimated that at least 50% of dogs have dentine exposure due to enamel hypocalcification, uncomplicated crown fractures or caries (Soukup et al. 2015). Areas of dentine exposure are initially slightly darker and less shiny than enamel, but over time typically become stained and appear brown or black. Conditions which expose the pulp are painful and may lead to infection without overt clinical signs (Bender 2000, Hasselgren 2000, Brynjulfsen et al. 2002, Hargreaves & Kaiser 2004). Likewise, dentine exposure can create pain (sensitivity) as well as endodontic infection via the exposed dentinal tubules (Trowbridge et al. 2002, Startup, 2012). Dogs and cats often appear stoic regarding tooth pain as their need to eat overpowers their drive to avoid pain. However, many clients report that their pet is more sociable, active and/or eats better following appropriate therapy. Teeth with direct pulp exposure (Fig 4) require prompt extraction or root canal therapy. Those with dentine exposure from any cause should be radiographed to determine if there is evidence of loss of tooth vitality, inflammation or infection. There are many radiographic signs of tooth non-vitality but the two most common are periapical rarefaction and a larger endodontic system compared to surrounding or contralateral teeth (Fiani & Arzi 2010). If any tooth has radiographic signs of non-vitality, extraction or root canal therapy is necessary. If the tooth appears vital, restoration of the damaged area is recommended. This can take the form of a bonded sealant, composite restoration, or crown therapy (complete coverage of the crown of the tooth with a laboratory-fabricated material)(Woodward 2008, Theuns & Niemiec 2011). Tooth resorption in cats has a prevalence of 20–70% (depending on the study) and is increasing in dogs (Arnbjerg 1996, Verstraete et al. 1996, Clarke & Cameron 1997, Ingham et al. 2001, Peralta et al. 2010a, 2010b, Bellows 2010b). This non-carious resorption of the tooth results from active destruction of tooth substance by odontoclasts. Currently, the aetiology of type 2 is unknown, but gingival inflammation is thought to stimulate odontoclasts in type 1 lesions in cats, (DuPont & DeBowes 2002, Farcas et al. 2014). Tooth resorption commences on the root surface, specifically at the cemento-enamel junction for type 1 lesions. The resorption then enters and destroys the dentine and extends into the root structure, possibly involving the entire length of the root. The resorption often moves coronally into the dentine in the crown of the tooth. Destruction of the coronal dentine results in undermining the enamel and, once the dentine support is gone, the enamel breaks off, exposing the underlying dentine (Reiter & Mendoza 2002, DuPont 2010, Gorrel 2015). In human patients, subgingival lesions are not reported to be painful (Heithersay 2004) but once the lesion extends into the oral cavity, tooth resorption becomes a very painful condition. Many animals will show pain on direct stimulation of the lesion so care should be taken during examination to avoid touching these painful teeth. As with fractured teeth, dogs and cats affected with tooth resorption rarely show obvious signs of oral pain in the home environment, but there are studies showing behavioural changes in cats with resorption that improve when treated (Bellows 2010b, Furman & Niemiec 2013). The first sign of tooth resorption on examination of a conscious animal is a small area of gingival enlargement at the gingival margin. The hyperplastic gingiva also often appears inflamed along the gumline. As disease advances, defects in the tooth surface will be noticed. Under anaesthesia, an explorer probe may be used to feel the rough cemento-enamel junction. Advanced lesions show obvious signs of tooth destruction, possibly resulting in painful crown fracture. All teeth with clinical evidence of tooth resorption must either be extracted or treated with crown amputation, depending upon radiographic findings (DuPont 1995, Reiter & Mendoza 2002, Niemiec 2008a) (Fig 5). Computed tomography scan (CT) is currently the gold standard for imaging maxillofacial trauma, especially in the temporomandibular joint and orbital areas (Bar-Am et al. 2008, Winer et al. 2018, Tundo et al. 2019). Minimally-invasive fixation techniques (such as interdental fixation and intraoral acrylic splints (Fig 6) are recommended for oral and maxillofacial trauma repair (Taney & Smith 2010, Verstraete 2015). These reduce iatrogenic trauma, do not require tissue disruption to remove, and in many cases are superior to screws and external fixators. Titanium miniplates can be effective, especially in edentulous areas or in cases of significant comminution, and may not require removal, but should only be used by personnel specifically trained in their use (Arzi & Verstraete 2015). In other cases in which internal fixation is needed, interfragmentary wires can be effective. The oral cavity is the fourth most common site for tumours, accounting for approximately 5–7% of tumours in dogs and about 10% in cats (Frew & Dobson 1992, Liptak & Withrow 2007). Melanoma and squamous cell carcinoma have been shown to be the most common oral malignancy in dogs and cats, respectively (Todoroff & Brodey 1979). However, the most common growth in the mouth of a dog is a peripheral odontogenic fibroma, which is benign (DeBowes 2010, Chamberlain & Lomner 2012). Since different tumours may have similar physical appearances (especially early in the course of disease), early biopsy of all oral lesions is strongly recommended. Diagnostic imaging (preferably CT) to determine extent of disease and staging (if indicated) is also important. Tumour management is multimodal, including resective surgery, immunotherapy, chemotherapy and/or radiation therapy. The American Veterinary Dental College and WSAVA Dental Guidelines committee consider any occlusion which creates occlusal trauma to be a malocclusion. This includes class III malocclusion in brachycephalic dogs when it results in trauma to the mandibular gingiva or mandibular canine teeth. Malocclusions may be purely cosmetic or result in tooth, gingiva or lip trauma that creates pain despite the lack of obvious outward clinical signs (Fig 7). In addition, if malocclusions are left untreated they can result in severe complications including tooth fracture, tooth death and oronasal fistulae (Fig 2). Therapy is not indicated for purely cosmetic reasons (Gawor 2013) but all cases of traumatic malocclusion should be addressed (Yelland 2013). Treatment options for traumatic malocclusions include interceptive (extractions, odontoplasty, endodontic therapy) or corrective methods (orthodontic movement). The majority of skeletal malocclusions have a genetic component and so occlusal assessment is an important breeding selection criterion. As a profession, we must continue to voice the need for optimal oral health for animals, advocate for proper dental care for our patients, and educate our clients on the importance of quality dental care to the daily welfare of their pets (Fraser et al. 1997). By utilising the Five Animal Welfare Needs as our guide, regular dental examination and proper therapy will help to address infection, control pain, relieve suffering and allow return to normal behaviour. Dental extractions are unfortunately one of the most frequent surgeries in veterinary medicine and can be challenging. There are numerous iatrogenic complications that can result from improper extraction techniques, the most common being retained tooth roots. Contrary to popular belief, retained roots do not resorb on their own, unless advanced tooth resorption has occurred on most of the root in question (Woodward 2006, Moore & Niemiec 2014). While there are rarely any obvious symptoms noted by clients, they do appear to continue to create pain and infection for the patient. In addition to retained roots, wound dehiscence and more severe complications such as jaw fracture, oronasal fistula and orbital trauma can occur when proper technique is not followed (see local effects of periodontal disease above). Dental radiographs are critical to assist in extraction technique decisions, and to avoid complications by providing information on actual number of roots, degree of ankylosis, and amount of remaining bone. Post-operative dental radiographs are also recommended to ensure complete removal of the roots and to ensure that no problems arose during extraction (Holmstrom et al. 1998). Extraction forceps should not be used until the tooth is very loose (Wiggs & Lobprise 1997b). Extraction of multi-rooted teeth begins with sectioning into single rooted segments (Charmichael 2002, Fitch 2003) and, for this purpose, a high-speed handpiece with a new dental bur for every procedure is recommended. Difficult extractions (canine and carnassial teeth and those with root abnormalities such as ankylosis) as well as retained roots are generally best extracted via an open approach (surgical flap creation and bone removal) (Woodward 2006). Appropriate equipment will greatly improve speed of speed procedures and decrease complications during extraction. An appropriate surgical pack would include: extraction forceps, needle holders, scalpel and scalpel handle, thumb forceps, periosteal elevators, and dental elevators and/or luxators of a variety of species-appropriate sizes (Table 2). Small sharp elevators should be used to carefully elevate teeth. Regular sharpening of elevators will improve their efficiency, lengthen their useful life, and reduce surgical trauma, protecting both the investment of the veterinary hospital alongside the patient's welfare. A) Scaling instrumentation: Tier 1: Tier 2 and 3 should have the above plus: 2. Mechanical scaling: sonic or ultrasonic (piezoelectric, magnetostrictive) B) Radiology equipment 2. Dental radiology equipment – rather than radiology generator plus: Digital dental radiology should be used in all tier 3 countries. C) Oral surgery A basic soft-tissue oral surgery kit includes: Note that a variety of sizes of the above equipment should be available for cats, medium and large breed dogs. Tier 1 country should have: Tier 2 and 3 should have the above plus: 1. High speed dental unit and handpiece with assorted burs A professional dental cleaning requires equipment for supra- and sub-gingival scaling, both mechanical (ultrasonic or sonic) and manual, as well as a means for polishing. In addition, diagnostic equipment is critical for accurate disease diagnosis. Quality lighting is also essential for oral evaluation. A dental mirror and magnification will further improve diagnostic yield (Table 2). Dental problems are some of the most common encountered in small animal practice. These diseases present a significant welfare issue in pets and should be attended to expediently and in an appropriate manner. These guidelines provide the fundamentals of good dental care to benefit the patient, operator and practice. The full guidelines can be found at: https://doi.org/10.1111/jsap.13112.