Original article
Effect of surgical exposure technique, age, and grade of impaction on ankylosis of an impacted canine, and the effect of rapid palatal expansion on eruption: A prospective clinical study

https://doi.org/10.1016/j.ajodo.2012.10.017Get rights and content

Introduction

This study had 2 aims: (1) to assess whether the surgical exposure technique, the patient's age, and the grade of impaction are associated with ankylosis of the impacted canine; and (2) to investigate the effect of rapid palatal expansion on an impacted canine's automatic eruption.

Methods

The sample for this prospective longitudinal study consisted of 118 orthodontic patients (72 female, 46 male) who were treated surgically and orthodontically by the first author (S.I.K.) over 18 years. The patients' ages at the beginning of therapy ranged from 11.2 to 46.1 years. They had 157 impacted canines (150 maxillary, 7 mandibular), grouped in 7 categories (grades I-VII) according to their radiographic position in the orthopantomogram at the onset of treatment. Univariate and multivariate generalized estimating equation logistic regression analyses were used to assess the effect of the predictors of interest on ankylosis. (In this research, a broad definition of “ankylosis” was used, to include impacted canines immobilized a priori or during traction, due to all the possible causes that could contribute to immobilization, such as all types of external tooth resorption and other known or unknown factors.)

Results

Thirty-eight canines erupted spontaneously after space gaining, and the other 119 were treated surgically with an open (57 cases) or a closed (62 cases) exposure technique. Eleven canines of the 119 that were treated surgically had ankylosis, either a priori or during orthodontic traction. The percentages of ankylosis were 3.5% in the open technique and 14.5% in the closed technique. Evidence of statistical association was found between age and ankylosis, grade of impaction and ankylosis, and rapid palatal expansion and automatic eruption of the impacted canine.

Conclusions

Evidence of an association between exposure technique and ankylosis was found. Additionally, there was evidence that the grade of impaction and the patient's age are significant predictors of ankylosis, as is the use of rapid palatal expansion a predictor of automatic eruption.

Section snippets

Material and methods

All participants in this clinical study came from the private practice of the first author, who treated all the impacted canines surgically and orthodontically over a period of 18 years (1994-2012). No specific inclusion or exclusion criteria were applied, since all patients who agreed to undergo therapy were included.

The canines were considered impacted when their roots were fully developed but the teeth were still covered with bone or mucosa.

We implemented a new grading method to categorize

Results

From 1994 to 2010, the number of patients who came to the surgery and remained for therapy after the diagnosis of a dental or skeletal problem of their maxillofacial system was 2899 (number of canines, 11,596). In 118 (4.1%) of these patients, the impaction of at least 1 canine was diagnosed.

This clinical study was based on 118 orthodontic patients, 72 female and 46 male, with 157 impacted canines. The CONSORT flowchart (Fig 4) shows patient flow, and Table I gives the baseline characteristics

Discussion

Our clinical study focused first on the complication of ankylosis regarding the surgical exposure technique (open or closed), the patient's age, and the grade of impaction, and then on the effect of rapid palatal expansion on the automatic eruption of the impacted canines in the maxilla.

All participants for this clinical study came from the private practice of the first author, who treated all impacted canines orthodontically and surgically. In this way, every patient, at each stage of the

Conclusions

There is some evidence of an association between surgical exposure technique, age, severity of impaction, and ankylosis. However, these findings should be interpreted with caution because the number of events was small.

Rapid palatal expansion appears to be associated with automatic eruption of impacted canines.

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    The authors report no commercial, proprietary, or financial interest in the products or companies described in this article.

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