A paper to get your teeth into!
Having something to chew is important for our dogs’ health but some of the commonly marketed toys and food stuffs for dogs to chew are as hard or harder than tooth enamel and can therefore damage teeth.
Tooth fracture is commonly seen in practice with a reported prevalence of 21.5% (Soukup et al., 2015). Tooth fractures which expose the pulp are complicated crown fractures. Pulp exposure to the oral cavity results in pulp necrosis and pain and therefore these teeth should be extracted or treated endodontically (root canal treatment). Those fractures which are limited to the enamel and dentine are known as uncomplicated but can still be problematic as the porous dentinal tubules can translocate bacteria from the oral cavity to the living part of the tooth to cause pulp necrosis. The maxillary fourth premolar teeth are most susceptible to fracture during chewing and make up 29.5% of all fractured teeth (Capik et al., 2000, Soukup et al., 2015). Prior to the publication of the paper ‘The Incidence of Radiographic Lesions of Endodontic Origin Associated with Uncomplicated Fractures of the Maxillary Fourth Premolar in Canine Patients (Goodman et al., 2020), it was not known how many uncomplicated crown fractures resulted in inflammation or necrosis of the tooth pulp, and therefore what the recommendations should be if you encounter tooth injuries like this in practice.
The Goodman et al. paper is a retrospective study of 111 uncomplicated crown fractures of the maxillary 4th premolar, and is the first to investigate the pathology that can be encountered associated with seemingly innocent or ‘asymptomatic’ tooth injuries in dogs. Radiography was employed to identify the presence of changes in the bone or periodontium around the root apices of the teeth. The frequency of periapical radiolucency on the radiographs associated with teeth with enamel-dentine fractures was found to be 24.3% by the authors. There were no radiographic changes seen in the control population with unfractured teeth. The study also showed that there was a higher likelihood of radiographic changes in larger dogs compared to smaller ones. This statistic could be an underestimate knowing firstly that 30-40% of mineral content must be lost from bone before changes are seen radiographically. Secondly, periapical lesions can take more than 30 days to develop post-fracture.
The lesions described in this study associated with chronic pulpitis or necrosis can certainly cause pain and discomfort (tooth ache) in humans and therefore we must infer that a minimum of 24.3% of dogs presenting with what might appear to be quite superficial tooth injury, might have painful changes associated with toothache. It should also be remembered that most tooth fractures are not noticed by clients and are therefore diagnosed in the consulting room when a pet is being presented for other reasons or is undergoing a general health check.
It is reminder that the veterinary profession should not be complacent in treating fractured teeth and that it is our responsibility to educate clients to the dangers of ignoring any fractured tooth, particularly when there is a significant risk that the fracture is causing pain and discomfort to the patient. From this paper, the recommendation should be that any tooth with an uncomplicated crown fracture would benefit from radiography. Root canal treatment should be offered as a treatment option if radiographic changes are apparent. The only suitable alternative to this is tooth extraction. Should changes not be visible radiographically, then repeat radiographs should be taken at an appropriate interval.
Although the premolars are the most commonly fractured teeth (Soukup et al., 2015) it would be beneficial to understand the prevalence of pathology associated with other teeth. Therefore, further studies focussing on both maxillary and mandibular canines, incisors and molars using imaging modalities such as CT or cone beam CT which enable earlier detection of changes associated with endodontic disease (Jorge et al., 2008, Campbell at al., 2016) would prove invaluable.
Written by Alix Freeman, BVDA
References
Campbell RD, Peralta S, Fiani N and Scrivani PV (2016) Comparing Intraoral Radiography and Computed Tomography for Detecting Radiographic Signs of Periodontitis and Endodontic Disease in Dogs: An Agreement Study. Frontiers in Veterinary Science 3, doi: 10.3389/fvets.2016.00068
Capík I, Ledecky V and Ševčík A (2000) Tooth fracture evaluation and endodontic treatment in dogs. Acta Veterinaria Brno 69, 115-122. Available from: https://actavet.vfu.cz/media/pdf/avb_2000069020115.pdf
Jorge, EG, Tanomaru-Filho M, Gonçalves M, Tanomaru JMG (2008) Detection of periapical lesion development by conventional radiography or computed tomography. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology 106, 56-61, doi: 10.1016/j.tripleo.2008.03.020
Goodman AE, Niemiec BA, Carmichael DT, Thilenius S, Lamb KE and Tozer E (2020) The Incidence of Radiographic Lesions of Endodontic Origin Associated with Uncomplicated Crown Fractures of the Maxillary Fourth Premolar in Canine Patients. Journal of Veterinary Dentistry 37, 71-16. doi: 10.1177/0898756420946500
Soukup JW, Hetzel S, Paul A (2015) Classification and Epidemiology of Traumatic Dentoalveolar Injuries in Dogs and Cats: 959 Injuries in 660 Patient Visits (2004-2012). Journal of Veterinary Dentistry 32, 6-14. doi: 10.1177/089875641503200101