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Basics ⬇

Basics

Overview

  • A persistent (retained) deciduous tooth is one that is still present when the permanent tooth begins to erupt or has erupted.
  • Numerous factors influence the exfoliation of deciduous teeth: lack of a permanent successor; ankylosis of the deciduous crown or root to the alveolus; and failure of the developing permanent crown to contact the deciduous root preventing resorption of the deciduous root.

Signalment

  • More common in dogs than cats.
  • More common in small-breed dogs (e.g., Maltese, poodle, Yorkshire terrier, etc).
  • Occurs during permanent tooth eruption phase-beginning at 3 months of age for the incisors and 6–7 months of age for the canine teeth and molars.
  • Persistent deciduous teeth may go undetected and therefore undiagnosed until adulthood.
  • No sex predilection.

Signs

General Comments

  • Persistent deciduous teeth can cause the permanent teeth to erupt in an abnormal positions resulting in a malocclusion. Early recognition and intervention is essential.
  • Maxillary canine teeth erupt mesial (rostral) to the persistent deciduous canine teeth. This can narrow the space (diastema) between the maxillary canine tooth and the third incisor, leaving no room for the mandibular canine tooth to occupy.
  • Mandibular canine teeth erupt lingual (medial) to the persistent deciduous teeth. This can result in a narrow space between the lower canines (base narrow), resulting in impingement on the soft tissue of the hard palate.
  • All permanent incisors erupt lingual to the persistent deciduous incisors. This can result in a rostral (anterior) crossbite.

Physical Examination Findings

  • Presence of a deciduous tooth with the permanent tooth either partially or fully erupted.
  • Abnormal position of the permanent tooth due to persistence of the deciduous tooth.
  • Oral malodor from accumulation of debris and plaque due to crowding of the permanent tooth and the persistent deciduous teeth.
  • Local gingivitis and early-onset periodontal disease due to plaque accumulation from crowding.
  • Oronasal fistula from base-narrow mandibular permanent canine teeth (linguoversion).
  • Deciduous tooth present with no permanent successor.
  • Deciduous tooth is usually smaller than the permanent tooth.
  • Without underlying permanent tooth, deciduous tooth will often remain intact and viable, though can eventually exfoliate.

Causes & Risk Factors

  • Cause is unknown but is suspected to have a genetic basis.
  • Small-breed dogs are predisposed.

Diagnosis ⬆ ⬇

Diagnosis

Differential Diagnosis

  • Supernumerary teeth
  • Gemination of the crown

CBC/Biochemistry/Urinalysis

N/A

Other Laboratory Tests

N/A

Imaging

Intraoral Radiography

  • Distinguish between permanent teeth and deciduous teeth.
  • Provide evidence or extent of root resorption of the deciduous tooth.
  • Identify dental abnormalities prior to extraction, including persistent deciduous tooth with no permanent successor, retained root with crown missing, and unerupted permanent tooth.
  • Identify relationship of deciduous root and permanent crown prior to extraction.

Diagnostic Procedures

  • Complete oral examination-charting of oral cavity to indicate presence of deciduous teeth, malpositioned teeth, missing teeth, soft tissue trauma, and other abnormalities.
  • Appropriate preoperative diagnostics when indicated prior to procedure.

Pathologic Findings

N/A

Treatment ⬆ ⬇

Treatment

Client Education

  • Persistent deciduous teeth may be prevalent in certain breeds.
  • Start looking at teeth from the first puppy or kitten visit.
  • Inform owners that you will be evaluating for exfoliation of deciduous teeth as well as proper eruption of permanent teeth.

Surgical Considerations

  • Ideally, extract the deciduous tooth as soon as the permanent tooth has erupted through the gingiva.
  • General anesthesia with endotracheal tube in place and cuff inflated.
  • Intraoral radiographs.

Extraction

  • Careful, gentle elevation is critical. Excessive force or pressure can damage the developing permanent tooth.
  • If a permanent tooth has erupted in an abnormal position, full root extraction of the deciduous tooth is essential.
  • A fractured or retained root may need to be removed with a gingival flap.
  • In some cases, the root may have already undergone resorption and the remaining crown needs to be extracted.

Medications ⬆ ⬇

Medications

Drug(s)

  • Topical oral antimicrobial rinse prior to extraction.
  • Pain management prior to, during and following extraction.

Contraindications/Possible Interactions

N/A

Follow-Up ⬆ ⬇

Follow-Up

Patient Monitoring and Homecare

  • After surgery, restrict activity for the rest of the day.
  • Soft diet for 24 hours-canned food or moistened dry kibble.
  • Analgesia (NSAIDs) for 24–36 hours post-op.
  • No chew toys for 24 hours.
  • Oral rinse (chlorhexidine) for 3–5 days if indicated.
  • Continue daily tooth brushing after 24 hours.

Prevention/Avoidance

May be prevalent in certain breeds and lines-avoid similar breeding.

Possible Complications

  • Malocclusion of permanent teeth may need to be treated.
  • Base narrow (linguoversion) of the mandibular canine teeth.
  • Rostral crossbite.
  • Rostrally deviated maxillary canine teeth.

Expected Course and Prognosis

  • Once extracted, there should be no further problems.
  • Gingiva generally heals uneventfully.
  • Prognosis depends on occlusion after eruption of permanent teeth is complete.

Miscellaneous ⬆

Miscellaneous

Abbreviation

NSAID = nonsteroidal anti-inflammatory drug

Suggested Reading

Wiggs R, Lobprise H. Veterinary dentistry, principles and practice. Philadelphia: Lippincott-Raven, 1997.

Author Randi Brannan

Consulting Editor Heidi B. Lobprise