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Root resorption associated with ectopically erupting maxillary

European Journal of Orthodontics 33 (2011) 483–491 © The Author 2010. Published by Oxford University Press on behalf of the European Orthodontic Society.doi:10.1093/ejo/cjq085 All rights reserved. For permissions, please email: journals.permissions@http://www.wenkuxiazai.com Advance Access Publication 2 December 2010

Introduction

The incidence of impacted or ectopically erupting maxillary permanent canines has been reported to be 0.9 to 2.0 per cent (Thilander and Jakobsson, 1968; Ericson and Kurol, 1986). There are variations between different ethnic groups and genders (Becker, 2007). Many

studies comprising orthodontic patients have shown a strong prevalence for this anomaly in females (female:male = 2.3:1 or 3:1; Dachi and Howell, 1961; Becker et al., 1981; Oliver et al., 1989). However, a random Israeli population study showed this to be approximately equal in males and females (Brin et al., 1986).Ectopically erupting and untreated impacted canines may cause several complications, such as displacement of the adjacent incisors, formation of follicular cysts, canine ankylosis, canine internal resorption, external resorption of the canine and roots of adjacent teeth, shortening of the dental arch, and/or combinations of these conditions (Shafer et al., 1984). Root resorption of the adjacent permanent teeth is one of the most important and frequent complications. The results of several studies using computed tomography (CT) as a diagnostic method have shown that 48 per cent of ectopic canines caused root resorptions of varying severity (Ericson and Kurol, 2000b ; Bjerklin and Ericson, 2006). It Root resorption associated with ectopically erupting maxillary permanent canines: a computed tomography study

Pavlina Cernochova*, Petr Krupa** and Lydie Izakovicova-Holla*,***

*Clinic of Stomatology, Faculty of Medicine, **Clinic of Medical Imaging and Radiology, St. Anne’s University Hospital and ***Department of Pathophysiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic Correspondence to: Dr Pavlina Cernochova, Stomatologicka klinika FN u sv. Anny, Pekarska 53, 656 91 Brno, Czech Republic. E-mail: pavlina.cernochova@fnusa.cz SUMMARY The aims of this retrospective computed tomography (CT) study were to determine the occurrence of severe root resorption involving the pulpal canal of adjacent permanent teeth associated with ectopically erupting canines, and to verify the existence of related factors. The sample consisted of 255 consecutive patients (159 females and 96 males, mean age 18.4 and 16.8 years, respectively). Three hundred and thirty-four ectopic maxillary canines and adjacent teeth were analysed using CT images. Statistical significance was evaluated with chi-square and Fisher’s exact tests.

The results showed that severe root resorption of adjacent permanent teeth occurred in 17.7 per cent of ectopic canines and was equally common in females and males. Severe root resorption affected 12.6 per cent of the lateral incisors, 4.8 per cent of the first premolars, and 2.1 per cent of the central incisors. No relationship was found between the type or side of ectopic eruption, inclination of the longitudinal axis of the ectopic canine and the occurrence of severe root resorption. A significant relationship was found between a bucco-lingual position of the ectopic canine and root resorption (P < 0.05). Root

resorption mainly occurred in the apical third (57.6 per cent) and apical and middle thirds (27.1 per cent). A significant relationship existed between the occurrence of root resorption and complete loss of space for the erupting canine (P < 0.05). No association was found between alignment of the upper permanent incisor and root resorption. A widened dental follicle occurred in 15 per cent of ectopic canines but did not cause root resorption of the adjacent permanent teeth. Since root resorption is asymptomatic, early detection by radiographic examination is essential for correct diagnosis and treatment.

may be present from 9 years of age. Root resorption can be difficult to diagnose because its progress is asymptomatic and rapid. Root resorption penetrating into the pulpal canal and/or radically reducing crown root ratio may result in loss of the affected teeth.

The exact aetiology of root resorption associated with ectopic maxillary canines is unknown. Several possible causative factors have been considered, such as pressure and inclination of the erupting canine, follicular activity, orthodontic forces,

genetics, trauma, developmental insufficiencies

of immature roots, and their susceptibility to resorptive enzymes (

Ericson and Kurol, 1988; Arens, 1995; Ericson et al., 2002; Becker, 2007; Falahat et al., 2008).The presence or absence of root resorption determines the optimal treatment strategy. When root resorption occurs, surgical exposure and orthodontic traction of the canine are carried out. Orthodontic traction directing the canine from the roots of the affected teeth eliminates pressure and the resorptive

processes caused by the ectopically erupting canine. Extraction of the affected tooth may be the method of choice in subjects with severe root resorption.

The aims of the present study were to determine the

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