{"id":29933,"date":"2023-11-22T21:14:11","date_gmt":"2023-11-22T21:14:11","guid":{"rendered":"https:\/\/todaysveterinarynurse.com\/?p=29933"},"modified":"2024-02-04T12:42:11","modified_gmt":"2024-02-04T12:42:11","slug":"dentigerous-cysts-an-overview","status":"publish","type":"post","link":"https:\/\/navc.sitepreview.app\/todaysveterinarynurse.com\/dentistry\/dentigerous-cysts-an-overview\/","title":{"rendered":"Dentigerous Cysts: An Overview"},"content":{"rendered":"
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Abstract<\/b><\/p>\n

The purpose of an oral examination is to determine whether all teeth are erupted (visible) and in proper alignment, specifically whether the patient has primary dentition, permanent dentition, malocclusion, persistent deciduous teeth, or missing teeth within an arcade. If a tooth is missing, it should be noted in the patient\u2019s record and a history should be taken. An unerupted tooth is associated with potential development of a follicular dentigerous cyst. The sooner a dentigerous cyst is detected and treated, the less invasive the surgical treatment and the better the prognosis.<\/p>\n

Take-Home Points <\/b><\/p>\n

    \n
  • Dentigerous cysts (DTCs) are more common in dogs than in cats, especially brachycephalic breeds (e.g., pugs, Shih Tzus, Boston terriers, boxers).<\/li>\n
  • Any missing tooth should be noted in the patient\u2019s record and investigated to ensure that it is truly absent versus unerupted.<\/li>\n
  • Although any tooth can be affected, the tooth most likely to be affected by a DTC is the mandibular first premolar.<\/li>\n
  • Oral radiography is the preferred tool for identifying an unerupted tooth and\/or DTC.<\/li>\n
  • Histopathologic examination of cyst lining is needed for a definitive diagnosis of DTC.<\/li>\n
  • Complete en bloc removal of the affected tooth and cystic membrane is curative.<\/li>\n
  • Annual oral examination and radiographs are needed to ensure that a DTC has not recurred.<\/li>\n<\/ul>\n<\/div><\/div>\n

    S<\/span>ome clients bring their pet to the veterinary hospital because they notice a swelling on the face, sometimes large enough to cause facial asymmetry (<\/span>FIGURE 1<\/b><\/span>). Others may bring their pet in with no clinical signs other than a \u201cmissing tooth,\u201d which may be truly missing or may be unerupted and thus not visible. Even for patients presented for wellness examinations, with no client <\/span>complaints, an oral examination should be performed to determine whether all teeth are visible and in proper alignment. An unerupted tooth may lead to formation of a follicular dentigerous cyst (DTC); unerupted teeth and formation of DTCs are closely associated. The incidence of unerupted teeth developing into DTCs is low, but 1 study noted pathologic changes in 32.9% of cases secondary to unerupted teeth in humans.1<\/sup><\/span><\/p>\n

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    Figure 1. Gross presentation of a large dentigerous cyst with grey cystic fluid visible through mucosa (arrowheads).<\/p><\/div>\n

    Oral examinations are valuable for patients of all ages as early detection of DTCs leads to less invasive treatment and improved oral health and quality of life for the patient. <\/span><\/p>\n

    Odontogenesis<\/h2>\n

    Odontogenesis, or tooth development, is a process that includes the formation and eruption of primary and permanent teeth. Each individual tooth bud size, shape, and location is genetically predetermined.2<\/sup> Dogs and cats have diphyodont dentition, which means they have 2 sets of teeth within their lifetime; a primary set (deciduous) and a secondary set (permanent). Puppies should have a total of 28 primary teeth and kittens a total of 26 primary teeth within their oral cavity (<\/span>TABLE 1<\/b><\/span>).<\/span><\/p>\n

    \"\"<\/p>\n

    Molars are not preceded by primary teeth and thus are not visible in the mouth until adulthood. After the eruption of their permanent teeth, adult dogs should have 42 teeth and adult cats should have 30\u00a0teeth (<\/span>TABLE 2<\/b><\/span>).<\/span><\/p>\n

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    During Embryonic Development<\/h3>\n

    Odontogenesis begins while an animal is an embryo and continues for a short while after birth.2<\/sup> By day 30 of gestation, the dental papilla, enamel (dental) organ (an aggregate of cells around a developing tooth, responsible for enamel production), and dental follicle have formed.2<\/sup> Enamel is then formed and deposited by ameloblasts (cells within the epithelial lining of the enamel organ that secrete proteins that will later mineralize to form enamel) onto the developing tooth via the enamel organ and follicle.1<\/sup> Osteoclasts expedite eruption by resorbing alveolar bone and creating a pathway for the tooth to exit its bony crypt.3<\/sup> After a tooth has completely erupted, the enamel-forming organ is worn away.1<\/sup> <\/span><\/p>\n

    At 3 to 6 Weeks<\/h3>\n

    When a dog or cat is 3 to 6 weeks of age, the primary teeth usually begin erupting into the oral cavity,3<\/sup> and the primary incisors, canines, and premolars should be visible.<\/span><\/p>\n

    At 3 Months<\/h3>\n

    In dogs and cats around 3 months of age, the primary teeth will begin to exfoliate and make way for permanent dentition.3<\/sup> <\/span><\/p>\n

    At 6 Months<\/h3>\n

    At 6 months of age, all permanent teeth should have erupted into the oral cavity and be in proper alignment.3<\/sup><\/span><\/p>\n

    Dentigerous Cyst Formation<\/h2>\n

    Many factors affect tooth eruption (e.g., genetics, sex, environment, infection, skeletal deformities, persistent deciduous teeth, trauma).1,3,4<\/sup> Although DTCs have been strongly linked to unerupted permanent teeth, they reportedly affect primary teeth as well.1,2<\/sup> <\/span><\/p>\n

    The most common cause of unerupted teeth is lack of space.4<\/sup> Deciduous and permanent teeth need space to erupt properly. The eruptive force of a tooth emerging through the gumline enables the enamel organ around the tooth to tear and begin to dissolve. DTCs often result from disturbance to the normal eruption process (e.g., when there is not enough eruptive force to push a tooth past the buccal frenulum, when eruption is impeded by another tooth\/structure).5<\/sup> DTCs arise from the remnants of enamel organ that remain whole under the gumline.2<\/sup> Ameloblasts have the potential to produce fluid, which can result in cyst formation (<\/span>FIGURE 2<\/b><\/span>).1<\/sup> <\/span><\/p>\n

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    Figure 2. Illustration of a dentigerous cyst. Kip Carter<\/p><\/div>\n

    Diagnosis of Dentigerous Cysts<\/h2>\n

    DTCs are rarely noted in cats and are far more common among dogs, especially brachycephalic breeds (e.g., pugs, boxers, Shih Tzus, Boston terriers).6<\/sup> Unerupted teeth with secondary DTC formation can be diagnosed at any age and can affect any tooth. Depending on its size and location, a DTC can encompass a single tooth (<\/span>FIGURE\u00a03<\/b><\/span>)<\/span> <\/b>or several teeth (<\/span>FIGURE 4<\/b><\/span>).7<\/sup> The tooth that most commonly becomes impacted or embedded in the dog, leading to a DTC, is the mandibular first premolar.7<\/sup><\/span><\/p>\n