A new perspective on the etiology of impacted maxillary canines: timing factors not to be ignored—a review

Abstract Impacted maxillary canine (IMC) is a common clinical problem in Dentistry and can lead to various complications. However, the etiology is complex, and no definitive conclusions have been reached to date. Traditional etiological theories cannot fully explain the mechanisms underlying IMC and often show considerable disagreement. Inspired by the clinical effectiveness of early intervention and considering the characteristics of tooth eruption and development, this study proposes a new perspective on the etiology of IMC. The concept of timing factors is proposed, and the notion of a chronological–biological mismatch is employed to explain its significance, emphasizing that it should not be overlooked. The aim is to use timing factors as a linking element to shift IMC etiological research from the traditional static, terminal-position perspective to a dynamic, process-oriented approach, and to promote the transition from conventional single-mechanism models toward a multifactorial understanding of its etiology. Clinically, early interceptive strategies, such as extraction of primary canines and rapid maxillary expansion (RME), are highly effective when applied within critical periods, highlighting the practical significance of timing factors. Recognizing developmental timing as an important etiological element provides a new perspective for studying IMC, addresses the limitations of traditional theories, and can guide precise, individualized early interventions in the future.