Treatment for critically impacted maxillary canines: Clinical versus scientific evidence - A systematic review

Critically impacted maxillary canines are prone to fail to respond to conventional surgical exposure and orthodontic traction. Correct identification of a critical impaction requires enhanced diagnosis modalities and might lead to incorporating alternative surgical strategies in the treatment plan. Predictability of techniques such as apicotomy or tooth autotransplantation is, however, yet to be determined. The objective of this study was to systematically review treatment perspectives for critically impacted maxillary canines.

A systematic review of the available literature until april 2020 was conducted using an electronic search in Embase, Cochrane Central, Web of Science and PubMed databases. Randomised and non-randomised studies investigating treatment options and treatment outcome for buccally and/or palatally critically impacted maxillary canines were considered for the review. Information recorded concerned study design and setting, participants' characteristics and details regarding the type of intervention, types of outcomes measured and follow-up time. The included studies received a methodological quality scoring and risk of bias analysis according to a tool suggested by Murad et al (2018).

Five studies were included in the quality analysis, all case series. The included studies enrolled a total of 302 patients and counted 346 critical maxillary canine impactions. Apicotomy and autotransplantation were listed as potential surgical approaches with surgical outcome presented for both surgical strategies. Adequate esthetical and/or functional outcomes were reported in most of the included studies. According to the quality assessment tool used, the reviewed studies scored medium on the proposed scale.

Literature featuring protocols for identifying and treating critical maxillary canine impaction only consists of case series and case reports, which provide low level of evidence. The rather good results reported by the reviewed studies must be put into perspective as the methodology of these studies was insufficient and potential bias was identified. Comprehensive clinical research is needed to further investigate treatment options and form a basis for clinical guidelines.