20 July 2022

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Prevention of palatally displaced canines

Davide Elsido

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The maxillary canines usually emerge at the mean age of 10.5 years in girls and 11.5 years in boys, with individual variation of 3–4 years. In 2–3 per cent of the Caucasian population, these teeth fail to erupt and become impacted, which is defined as obstruction by hard or soft tissue structures and/or an ectopic eruption pattern.
Other definitions that are used in literature are: ectopic or displaced, meaning an abnormal position that may result in tooth impaction.
The aetiology of the impacted canines is obscure and probably. Early preventive measures in the mixed dentition for palatal canine impaction are desirable, due to the risk of root resorption of the neighbouring permanent incisors. Such resorptions have been reported to occur in 47 per cent of subject in the age range of 10–13 years. However, a considerable  variation  in  diagnostic  tools,  study  designs, sample  sizes,  and  research  approach  has  produced  results and conclusions that are sometimes conflicting and may be difficult to compare and interpret.
In the issue of November of The Angle Orthodontist, an article was published to investigate whether extracting the primary canine and primary first molar was more beneficial than extracting only the primary canine in improving the emergence rate of PDCs (palatally displaced canines). Thirty-two children aged 9.5–13.5 years with 48 PDCs were randomly allocated to either the double-extraction group (DEG) or single-extraction group (SEG). Clinical and radiographic examinations were performed at baseline and at 6-month intervals until the canine emerged or orthodontic treatment was started.
As suggested by literature, the ultimate criterion for successful outcome may not only be the rate of eruption/non-eruption of PDCs into the dental arch. It is also very important where in the mouth the canines emerge, as the distance from the emergence point and favorable position in the dental arch affects the orthodontic treatment length and cost.
As results, no significant difference was observed between groups. Significant predictors of canine emergence were initial canine angulation and space conditions at the beginning of treatment.
To conclude, double or single primary tooth extraction procedures are equivalent in supporting PDC eruption into the oral cavity and into a favorable position in the dental arch. Initial canine angulation and space assessments may be used as predictors of successful PDC eruption.

For additional information:  Double vs single primary tooth extraction in interceptive treatment of palatally displaced canines: A randomized controlled trial.