A canine is considered impacted if: 1. It is unerupted after 3/4 of its root development (Litsas and Acar, 2011), 2. The contralateral tooth has erupted earlier for at least 6 months with complete root formation or 3. The canine position is intraosseous at or beyond CS5 or 2 years after adolescent growth spurt or 6 month after its root completion (Lindauer et al., 1992).
On the other hand, palatally ectopic or displaced canines (PDCs) refers to intraosseous or infraosseous position of the canine before the expected time of the eruption.
PDCs are more common in female than male with a ratio of 7:3 (Mossey et al., 1994). Its prevalence is around 1.7 to 2% (Ericson and Kurol, 1988a, Ericson and Kurol, 1986).
Several interceptive options have been suggested for the management of PDCs including: 1. Extraction of the C alone (Ericson and Kurol, 1988) 2. Extraction of the C and D (Bonetti 2011) 3. Generous space opening using sectional fixed appliance and open could spring (Oliver 2001) 4. Headgear alone or combined with extraction of the C (Leonardi et al., 2010). 5. RME alone or in combination with TPA and/ or extraction of the C (Baccetti et al., 2011)
As we are living in the era of biological acceleration of tooth movement etc, it was believed that “the combined extraction of the C and D would not only lead to more space for the PDC to erupt but also could lead to more regional trauma and possibly “chasing” the PDC’s follicle to normalize the tooth path of eruption”.
Angle Orthodontists Journal in their July 2020 issue published an RCT to answer this question. The paper titled “Double vs single primary tooth extraction in interceptive treatment of palatally displaced canines”. As we know, the Scandinavians are the lead in this field, hence, the team was from Norway and was led by Dr Hadler-Olsen. This two arms RCT with 1:1 allocation included 32 patients and 48 PDCs. The two groups were: G 1: extraction of C G 2: extraction of C+D
In summary, the null hypothesis was accepted i.e. there was no significant different between the two interventions (64% for G2 vs 57% in G1 (P = .600)
What do you think?