Eruption pattern of the maxillary canines: features of natural eruption seen in PTG at the late mixed stage—Part I

Abstract

Aim To describe the variation of eruption pattern of maxillary canines in the late mixed stage of dentition seen in PTG when eruption was later natural. Methods Material for this longitudinal and retrospective register-based study consisted of 1454 PTGs of children living in Eastern Finland (mean age 9.3 years, SD 0.6). Natural eruption of a canine consisted of 744 PTGs (336 girls and 408 boys) including 1488 maxillary canines. The variables examined were treatment/natural eruption, overlapping, inclination, dental age, developmental stage of the canine and lateral incisor. Results Only 2.0% of maxillary canines had clear overlapping and 56.2% no overlapping was detected at the age of 8.5–10.5 years. Large inclination angle (≥ 25°) was found for 5.5% of examined canines. Overlapping of canine with lateral incisor root decreased as the development of canine root exceeded 1/3. Larger inclinations occurred at earlier stages but decreased significantly as the root developed from 1/3 to 1/2. Mean inclination was significantly larger at children with normal dental age and/or incomplete lateral incisors when overlapping occurred. Regardless overlapping mean inclination was larger if dental age was delayed and/or lateral incisors incomplete. Conclusion Some overlapping and larger inclination in maxillary canine are features of normal eruption pattern at an earlier stage of canine development and while lateral incisor is incomplete in PTG (8.5–10.5 years). In addition to the overlapping and inclination, stages of canine and lateral incisor root as well as dental age should be observed radiologically when evaluating erupting maxillary canine in children of this age.

Eruption pattern of the maxillary canines: features indicating treatment needs as seen in PTG at the late mixed stage—Part II

“…In the earlier stages of eruption and development, a maxillary canine is often seen in PTG to overlap with the lateral incisor (Ristaniemi et al 2022 ). The age of 8–9 years seems to be the turning point after which overlapping will decrease if the canine erupts normally (Fernández et al 1998 ; Sajnani and King 2012a ), whereas in abnormal eruption overlapping may increase (Sajnani and King 2012a ).…”

“…The inclination of a normally erupting maxillary canine has been shown in earlier studies to increase mesially until the age of 8–9 years after which the tooth progressively uprights itself (Fernández et al 1998 ; Sajnani and King 2012a ), whereas in an ectopic eruption path it will still be pronouncedly inclined after age of nine years (Sajnani and King 2012a ; Chalakkal et al 2011 ). Inclination during natural eruption has shown to decrease significantly as root development in the maxillary canine continues from one-third to halfway (Ristaniemi et al 2022 ).…”

“…Root development in a permanent maxillary canine will mainly (84.2%) have reached one-third to half of the final length by the age of 8.5–10.5 years (Ristaniemi et al 2022 ) and will usually be almost complete by the time the tooth erupts into the oral cavity (Nolla 1960 ; Haavikko 1970 ). Root development in the maxillary canines during natural eruption has been shown to be more advanced in girls (Ristaniemi et al 2022 ), while no difference has been found between impacted and normally erupting canines (Sajnani and King 2012a ).…”

“…It is notable that the maxillary lateral incisors are still mainly (78.5%) incomplete in children aged 8.5–10.5 years, with girls having complete lateral incisors more often than boys at this age (Ristaniemi et al 2022 ). It has been shown earlier that overlapping of a maxillary canine with a lateral incisor can be an early sign of abnormal eruption of the canine if the development of the lateral incisor is already complete (Fernández et al 1998 ).…”

Evaluation of Lateral Incisor Resorption Caused by Impacted Maxillary Canines Based on CBCT: A Systematic Review and Meta-Analysis

“…One-third of the root development in a maxillary canine is reached by the age of 8.5–10.5 years. Moreover, an early sign of canine impaction is overlapping with a lateral incisor in panoramic radiographs if the development of the lateral incisor is already complete [ 11 ]. The etiological factors of impaction may be local or systemic [ 10 , 12 ].…”