Puppy and kitten veterinary visits are already quite busy, what with conversations about vaccinations, deworming, spay/neuter surgeries and behavior training. But your physical exam of these little ones should always include an oral exam.
Quick review of normal dentition
Before beginning, let’s briefly review the normal dental arcades, an understanding that is, of course, essential to recognizing any abnormalities. Table 1 shows the dental formulae for both deciduous and permanent dentition in dogs and cats.1
|Deciduous (primary, baby)||2X (I:3/3, C:1/1, P:3/3, M:0/0 ) = 28||2X (I:3/3, C:1/1, P:3/2, M:0/0 ) = 26|
|Permanent (adult)||2X (I:3/3, C:1/1, P:4/4, M:2/3) = 42||2X (I:3/3, C:1/1, P:3/2, M:1/1) = 30|
Table 2 lists the approximate normal eruption times for deciduous and permanent dentition in dogs and cats.1
|Deciduous teeth||Permanent teeth|
|Incisors||3-5 weeks||3-5 months|
|Canine teeth||3-6 weeks||4-6 months|
|Premolars||3-10 weeks||4-6 months|
*Eruption times are approximate. Please note that there is considerable breed and individual variation; this chart is meant as a guideline only.
As you look at the mouth, the crowns of the teeth should be smooth, white, translucent and similar in color to adjacent teeth. The gingiva should be light pink, have a knife-edge gingival margin and may have stippling in areas. The mucosa should be light pink or should have normal dark pigmentation. The mucosa should be flexible, malleable, smooth and soft.
Now on to the problems you might encounter in a puppy or kitten mouth.
Persistent deciduous teeth
There should be only one tooth per position in the mouth; that is, there should never be two teeth of the same type in the same place at the same time.2,3 A deciduous tooth is persistent as soon as the permanent tooth begins to erupt into the mouth.2 A deciduous tooth can be persistent secondary to an incorrect eruption path of the permanent tooth (most common) or because a permanent successor is missing.2,3 Persistent deciduous teeth may be genetic, and they occur most often in small- and toy-breed dogs but can occur in any dog breed and in cats.2 Persistent deciduous teeth can cause malocclusion and predispose the pet to periodontal disease. Therefore, the persistent baby teeth should be extracted as soon as possible. Extraction can be performed closed (using a "blade technique”) or surgically, whichever you prefer.
I believe that every animal is entitled to a comfortable, functional occlusion (Figures 1-4). Normal occlusion involves several different indices. The first is the incisor teeth—the mandibular incisor teeth are positioned caudal to the corresponding maxillary incisor teeth, and the cusps of the mandibular incisor teeth rest on the enamel cingulum of the maxillary incisor teeth.4 The mandibular canine teeth occlude in the maxillary diastema equidistant between the maxillary canine tooth and third incisor tooth.4 The maxillary and mandibular premolar teeth interdigitate in a “pinking shear” relationship in which the mandibular premolar tooth is equidistant between the maxillary premolar teeth of the same and previous numbers; the mandibular premolars are lingual to the maxillary premolars.4 Finally, the carnassial teeth occlude such that the maxillary fourth premolar tooth is buccal to the space between the mandibular fourth premolar and first molar teeth.4
Deviation from these normal positions is a malocclusion.
• A class I malocclusion = malposition of one or more teeth, but the maxillary and mandibular dental arches are in a normal relationship (Figures 5-8)
• A class II malocclusion = mandibular distoclusion (Figures 9 and 10)
• A class III malocclusion = mandibular mesioclusion (Figures 11 and 12)
• A class IV malocclusion = maxillomandibular asymmetry, which can occur in a rostrocaudal, side-to-side or dorsoventral direction.4
Is a malocclusion genetic? Potentially. Jaw length malocclusions are considered genetic and class I malocclusions are typically considered nongenetic (with the exception of mesioverted maxillary canine teeth in Shetland sheepdogs and Persian cats).3 The maxillae and mandibles grow independently and can have growth surges resulting in mild, temporary disproportionate relationships.5 A very mild malocclusion may represent one of these growth surges, but a more moderate to severe malocclusion probably will require intervention.
Selective extraction of deciduous teeth to relieve a dental interlock or traumatic occlusion is called interceptive orthodontics.5 This should be performed as soon as possible, ideally as soon as the malocclusion is diagnosed. Relieving the deciduous malocclusion can help the pet achieve its full genetic potential for jaw growth and provide comfort and relief from traumatic occlusion.
Less severely linguoverted (‘base narrow’) deciduous mandibular canine teeth may be amenable to gingival wedge resection or crown extension.
Before malocclusion treatment, you will want to thoroughly discuss the plan with the owners, explaining each procedure option, possible complications, needed follow-up and monitoring and the prognosis. After deciduous malocclusion treatment, the pet’s occlusion should be monitored closely as the permanent teeth erupt, in particular the permanent maxillary and mandibular canine teeth. Further treatment may be needed depending on the pet’s final permanent dentition occlusion (the most common permanent teeth that need to be treated are the mandibular canine teeth). You should also discuss, where relevant, the potential for genetic heritability. Encourage spaying or neutering of the pet, and definitely discourage breeding. Always emphasize the goal of correcting a malocclusion is to achieve comfort and function for the pet.
If you identify fractured deciduous canine teeth, incisors or premolars with pulp exposure, you should extract them as soon as possible. Complicated crown fractured (pulp-exposed) immature permanent teeth can be treated with vital pulp therapy if the tooth is treated within 48 hours. If the tooth’s pulp is exposed more than 48 hours, the success rate of treatment drops.6
Vital pulp therapy is usually performed on young, immature permanent teeth (patients are typically 18 to 24 months old). These teeth are poor candidates for root canal therapy because of their thin dentinal walls and wide pulp cavities. Vital pulp therapy involves the removal of the coronal-most portion of the exposed pulp and placement of materials to promote healing of the pulp and restoration of the crown. After vital pulp therapy, treated teeth require periodic radiographs to monitor them for vitality for the life of the patient.
Cleft lip and palate
A primary cleft palate involves the lip and palate rostral to the palatine fissures.7 A secondary cleft palate involves the structures caudal to the palatine fissures (i.e. caudal to the incisive bone), including the hard and soft palates.7 A primary cleft palate forms if the nasal prominences fail to merge with the maxillary prominences, whereas a secondary cleft palate forms if the palatine processes fail to fuse.7
Cleft surgery is usually delayed until a pet is 3 to 4 months old, which allows for adequate nutrition and more tissue to be available for repair.8 If you suspect aspiration pneumonia has developed, obtain thoracic radiographs before surgery. Additionally, counsel owners on the possible genetic heritability of clefts and strongly discourage breeding of their pet.8
Surgical repair requires careful client and patient selection. The best chance of success is with the first surgical procedure, so postoperative client compliance is crucial. The pet will be required to wear an Elizabethan collar and will not be allowed to chew on toys or have any objects in its mouth for at least four weeks. If your client is unable to ensure this compliance or the pet is unable to be controlled, then plan to delay surgery until compliance is more likely to be achieved.
There are various ways to treat secondary cleft palates. Two of the most common are the modified von Langenbeck technique and the overlapping-flap technique for the hard palate, and a double-layer appositional technique for the soft palate.8
Hypodontia and oligodontia
Hypodontia is the congenital absence of one to five teeth; oligodontia is the congenital absence of six or more teeth.3 Hypodontia is likely a genetic condition. It is common in small dog breeds, brachycephalic dog breeds and Chinese crested dogs.3 The teeth most commonly missing are the first and second premolars, incisors and mandibular third molar teeth.3 It is very uncommon to be missing a canine tooth or carnassial tooth, thus radiographic confirmation of missing teeth is essential. There is not much you can do about these missing teeth other than to chart them so you remember the condition the next time you see the pet and so you can watch for any problems as the animal matures.
Unerupted teeth are teeth that are either impacted (have a physical obstruction to eruption) or embedded (lack sufficient eruption force).9 In dogs, the most common unerupted teeth are the mandibular first premolar teeth and the maxillary and mandibular canine teeth.10 Unerupted teeth should be extracted because of the potential for a dentigerous cyst forming.9,10 If a cyst is present, then perform enucleation of the cyst and submit a sample of the cystic lining for histopathology. Histopathology can confirm dentigerous cyst formation and can rule out more sinister disease processes, such as malignant transformation.9,10
Oral tumors can be characterized as odontogenic or nonodontogenic. Odontogenic tumors arise from remnants of embryonic tissues; most of these tumors are benign. Malignant odontogenic tumors are rare.11 Examples of odontogenic tumors are odontoma, peripheral odontogenic fibroma (previously called epulis), ameloblastoma and feline inductive odontogenic tumor (Figures 13-16).
Complete resection of these masses is curative. Some odontogenic tumors, like the ameloblastoma and feline inductive odontogenic tumor, are very locally aggressive. You should excise them completely with wide margins as soon as possible.
Nonodontogenic tumors seen in pediatric patients include viral-induced papilloma, squamous cell carcinoma and others. Nonodontogenic tumors can be malignant or benign and must be treated accordingly.
Of course, you will want to talk to every puppy and kitten owner about preventive dental care. But when you encounter any of these specific problems, be sure to take extra time to carefully explain what you’ve found and describe the treatment options to your clients. Remember to emphasize that any treatment plan that you recommend is ultimately for the comfort and function of the pet.
1. Wiggs RB, Lobprise HB. Oral examination and diagnosis. In: Veterinary dentistry, principles and practice. Philadelphia: Lippincott-Raven; 1997;87-103.
2. Hobson P. Extraction of retained primary canine teeth in the dog. J Vet Dent 2005;22:132-137.
3. Niemiec BA. Pathology in the pediatric patient. In: Veterinary periodontology. Ames, Iowa: John Wiley & Sons; 2013;89-126.
4. Normal occlusion. American Veterinary Dental College website. https://www.avdc.org/Nomenclature/Nomen-Occlusion.html#normal. Accessed August 20, 2017.
5. Wiggs RB, Lobprise HB. Pedodontics. In: Veterinary dentistry, principles and practice. Philadelphia: Lippincott-Raven; 1997;167-185.
6. Clarke DE. Vital pulp therapy for complicated crown fracture of permanent canine teeth in dogs: a three-year retrospective study. J Vet Dent 2001;18:117-121.
7. Kelly KM, Bardach J. Biologic basis of cleft palate and palatal surgery. In: Verstraete FJM, Lommer M. Oral and maxillofacial surgery in dogs and cats. Edinburgh: Saunders Elsevier; 2012;343-350.
8. Marretta SM. Cleft palate repair techniques. In: Verstraete FJM, Lommer M. Oral and maxillofacial surgery in dogs and cat. Edinburgh: Saunders Elsevier; 2012: 351-361.
9. Babbitt SG, Volker MK, Luskin IR. Incidence of radiographic cystic lesions associated with unerupted teeth in dogs. J Vet Dent 2016;33:226-233.
10. D’Astous J. An overview of dentigerous cysts in dogs and cats. Can Vet J 2011;52:905-907.
11. Chamberlain TP, Lommer MJ. Clinical behavior of odontogenic tumors. In: Verstraete FJM, Lommer M. Oral and maxillofacial surgery in dogs and cat. Edinburgh: Saunders Elsevier; 2012;403-410.