Sune Ericson

Radiographic examination of ectopically erupting maxillary canines

This study analyzes the need for and possibility of obtaining further information from different radiographic procedures in 125 children with potential ectopic eruption of the maxillary canines. After clinical examination of 3,000 10 to 15-year-old children, it was found that 7% needed radiographic examinations for determination of the canine position. Eighty-four children (2.8%), with a total of 125 potential ectopically erupting maxillary canines diagnosed clinically and by means of periapical radiographs, were selected and a stepwise extended radiographic diagnostic procedure was used. Most canines in ectopic eruption were positioned palatally; the positions could be assessed with sufficient accuracy from conventional periapical films in 92% of the cases. Only in 37% of the cases, however, could the lateral incisor be projected free from the ectopic canine by the intraoral technique. The lamina dura of the lateral incisor facing the canine was often found to be interrupted. For 29% of the ectopic canines, the lateral incisors could neither be projected free nor judged free from resorptions and a supplementary polytomographic investigation was believed to be necessary. The number of resorbed teeth was doubled by polytomography and altogether 12.5% of the ectopic canines caused resorptions. A stepwise radiographic procedure including polytomography is described and recommended in cases of ectopic eruption of maxillary canines for determining the correct position and ruling out or confirming resorptions on incisors, thereby optimizing the orthodontic treatment planning.

Early treatment of palatally erupting maxillary canines by extraction of the primary canines

The effect of extraction of the primary canine on palatally erupting ectopic maxillary canines was analysed. There were 46 consecutive ectopic canines, in 35 individuals, aged 10.013.0 years (mean age 11.4 years) at the time of discovery of the ectopic eruption. All cases showed no or minor space loss. After extraction of the primary canine, the children were investigated clinically and radiographed at 6-month intervals for up to 18 months. In 36 of the 46 canines (78%) the palatal eruption changed to normal; 23 already showed improved positions after 6 months and 13 after 12 months. No new cases normalized after 12 months. We suggest that extraction of the primary canine is the treatment of choice in young individuals to correct palatally ectopically erupting maxillary canines provided that normal space conditions are present and no incisor root resorptions are found.

Resorption of incisors after ectopic eruption of maxillary canines: a CT study.

The purpose of the study was to analyze the extent and prevalence of resorption of maxillary incisors after ectopic eruption of the maxillary canines in a sample of subjects referred to an orthodontic specialist clinic for consultation. The subjects consisted of 107 children, 39 boys and 68 girls, between 9 and 15 years of age (mean 12.5 years), with 156 ectopically and 58 normally erupting maxillary canines. All children were subjected to a basic clinical and intraoral radiographic investigation. These radiographs were supplemented with computerized tomography (CT) of the upper alveolar bones in order to get more precise information on the positions and relationships between the maxillary canines and adjacent incisors and to evaluate resorptions on the roots of the incisors. The results showed that, relative to the roots of the adjacent incisors, the crowns of 21% the ectopically positioned canines were located to the buccal, 18% to the distobuccal, 27% to the lingual, 23% to the distolingual, 5% apically and 6% between the central and lateral incisors. Ninety-three percent of the ectopically positioned canines were in contact with the roots of the adjacent lateral incisor and 19% were in contact with the central incisor. The corresponding figures for the normally erupting canines were 49%. Resorptions on the roots of the incisors adjacent to the ectopically positioned canine occurred in 38% of the laterals and in 9% of the centrals. The resorptions were graded and tended to be extensive. Among the 58 resorbed lateral incisors, resorptions were slight in 31%, moderate in 9%, and severe with pulpal involvement in 60%. The corresponding figures for the 14 resorbed centrals were 36%, 21%, and 43%, respectively. About 60% of the resorptions involved the middle and apical thirds, the tip of the apex not included. On the sides with normally erupting canines, 3 lateral maxillary incisors were slightly or moderately resorbed distally. In all, 51 of the 107 subjects with ectopically erupting maxillary canines (48%) had resorbed maxillary incisors during the eruption of the maxillary canines. There were statistically significant correlations between ectopic eruption of the maxillary canine, contacts between the teeth and resorptions on the adjacent incisors. It was concluded that resorption on maxillary incisors after ectopic eruption of the maxillary canines is a more common phenomenon than previously reported and has to be considered in all cases with seriously diverging eruption of maxillary canines. It was also concluded that the resorptions of the roots of the incisors were caused by pressure during the eruption of the adjacent, aberrant canine. Finally, it was shown that CT scanning substantially increased the detection of root resorptions on incisors adjacent to ectopically erupting maxillary canines (about 50%). The sensitivity of intraoral films was low when diagnosing the resorptions, being calculated to 0.68.

Resorption of maxillary lateral incisors caused by ectopic eruption of the canines. A clinical and radiographic analysis of predisposing factors.

Factors predisposing to resorption of adjacent permanent lateral incisors caused by ectopic eruption of maxillary canines were evaluated. The subjects consisted of two groups: one with 40 lateral incisors with resorption caused by ectopic eruption and a control group of 118 ectopic eruption cases with no lateral incisor resorption. The mean age of the children in the two groups differed by only 0.7 of a year and ranged from 10.0 to 15.0 years, covering the normal eruption period of the maxillary canine. Resorption of lateral incisors was three times as common in girls as in boys. The resorption cases showed a more advanced dental development, a more medial canine position in the dental arch, and a slightly more mesial horizontal path of eruption (an average of 10 degrees) than that of the control cases. Factors such as the width of the dental follicle and proclination or distal tilting of the lateral incisor showed no correlation to the resorption. Potential resorption cases are always those in which the canine cusp in periapical and panoramic films is positioned medially to the midline of the lateral incisor. Such situations should be carefully investigated with polytomography if necessary. The risk of resorption also will increase with a more mesial horizontal path of eruption. From 10 years of age or younger, annual clinical examination by palpation of the canine eruption path is recommended. This clinical examination should be supplemented with a stepwise extended radiographic procedure in cases in which ectopic eruption of the maxillary canines is suspected.

Incisor Root Resorptions Due to Ectopic Maxillary Canines Imaged by Computerized Tomography: A Comparative Study in Extracted Teeth

The purpose of the study was to analyze the ability of computerized tomography (CT) scanning to discriminate maxillary incisor root resorptions caused by ectopically erupting canines. Seventeen maxillary incisors were radiographed in vivo by CT scanning. Contiguous transverse CT scans with a slice thickness of 2 mm were exposed perpendicular to the long axis of the lateral incisors and through the crown of the adjacent, ectopically positioned maxillary canine. Each scan was analyzed and the resorptions on the roots of the laterals were graded according to the maximum depth of the cavity. After the lateral incisors were extracted they were clinically inspected, photographed in different light settings and views, and probed at the contact area between the laterals and the canines. The assessment of the extent of resorption in 4 stages on the CT images compared with the in vitro observations of the extracted roots showed a high degree of agreement for the extent of loss of root substance for all teeth. We conclude that CT scanning performed with good technique accurately reveals tooth root resorption. The presence and influence of the inherent artifacts of tooth root resorption on CT scans are discussed.

How a Computerized Tomography Examination Changed the Treatment Plans of 80 Children with Retained and Ectopically Positioned Maxillary Canines

The purpose of this study was to analyze treatment outcome and treatment planning before and after a computerized tomography (CT) investigation of children with retained and ectopically positioned maxillary canines. Intraoral and panoramic radiographs, computerized tomographs, and, in some cases, lateral head films were taken of 80 children with 113 retained maxillary canines. The incisor roots of 39 of the 80 children had some measure of resorption. Forty-two children with retained maxillary canines also had a space deficiency. Diagnosis and a treatment plan were originally based on extraoral and intraoral photos, study models, the anamnesis, the status on the patients charts, conventional radiography, and, if available, lateral head films. Approximately one year later, the same examiner drew up a new treatment plan based on the same records but with a supplemental CT examination. The treatment plans of 35 (43.7%) of the 80 children were modified to reflect this new information. Of those patients with root resorption on the incisors adjacent to retained canines, more than half (53.8%) of the treatment plans were altered. Without the CT investigation, 11 children would not have been treated for resorption that had exposed the pulp of an incisor root and 13 who had no root resorption on their incisors would have had one or both lateral incisors extracted. The treatment plans of the latter were changed to nonextraction or extraction of premolars. A CT investigation is an important source of information for treatment planning for children with retained or ectopically erupting maxillary canines.

Does the canine dental follicle cause resorption of permanent incisor roots? A computed tomographic study of erupting maxillary canines.

We performed computed tomography (CT) on 107 children and adolescents aged 9-15 years with 176 unerupted maxillary canines (152 erupting ectopically and 24 erupting normally) to determine whether there is an association between widened dental follicles of the maxillary canines and resorption of the adjacent incisors during eruption. Contiguous axial (transverse) CT scans were obtained through the maxilla in the region of the canines. The width and shape of the dental follicles were recorded, as were any contacts between the follicles and the crowns of the maxillary canines and neighboring incisors. Fifty-eight lateral incisors (38%) and 14 central incisors (9%) had some type of root resorption. The position of the maxillary canine in relation to the root of the lateral incisor varied greatly, as did the width and shape of the canine dental follicle. Follicle width ranged from 0.5 mm to 7.0 mm. The mean +/- SD width of dental follicles was, on average, larger for the ectopically positioned canines (2.9 +/- 0.8 mm) than for the normally erupting canines (2.5 +/- 0.8 mm) (P < or = .01). We found that during eruption, the follicle of the erupting maxillary canine frequently resorbed the periodontal contours of adjacent permanent teeth but not the hard tissues of the roots. We concluded that the dental follicle did not cause root resorption of permanent teeth. Resorption of neighboring permanent teeth during maxillary canine eruption was most probably an effect of the physical contacts between the erupting canine and the adjacent tooth, active pressure during eruption, and cellular activities in the tissues at the contact points, all of which are part of the eruptive mechanism. The findings also confirm an association between root resorption of deciduous canines and the dental follicles of erupting permanent canines.

Incisor root resorption due to ectopic maxillary canines: a long-term radiographic follow-up.

OBJECTIVE To document the long-term fate of maxillary incisors with resorbed roots after correction of the associated ectopic canines. MATERIALS AND METHODS The subjects were recruited from 107 children and adolescents age 9-15 years (mean 12.5 years) at initial registration, with 156 ectopically positioned maxillary canines. The children were referred to the specialist orthodontic clinic for consultation because of the risk of incisor root resorption. Of 51 patients contacted, 16 failed to attend. Eight of the remaining 35 were excluded because their lateral incisors had been extracted, leaving 27 subjects for follow-up registration. At initial consultation, all subjects had undergone radiographic examination, including computed tomography (CT) scans. At the follow-up consultation, the radiographic examination was limited to intraoral films. RESULTS No resorbed incisor was lost during the 2- to 10-year follow-up period. The resorptive lesions had undergone repair in 13 teeth, remained unchanged in 12 teeth and progressed in 7 teeth. In the 13 teeth exhibiting signs of repair, no resorption was detectable in 11 teeth and minor resorption was detected in 2 lateral incisors. At the initial registration, severe or moderate resorption had been diagnosed in 12 lateral and 5 central incisors, compared with 11 lateral and 6 central incisors at follow-up. In 10 subjects initially diagnosed with resorption of 13 incisors, the lesions were no longer discernible on intraoral radiographs at follow-up. CONCLUSIONS Even in cases of severe resorption, the incisor roots show good long-term healing. Incisors with root resorption can be used in an orthodontic appliance system.

The dental follicle in normally and ectopically erupting maxillary canines: a computed tomography study.

The subjects in the study were children who were X-rayed because of increased risk for resorption following ectopically erupting maxillary canines. One hundred and seven children 9 to 15 years of age with 156 maxillary canines that were erupting ectopically and 58 normally were investigated by computed tomography (CT) to describe the features of the dental follicles of the erupting maxillary canines. Contiguous, transverse CT scans were exposed through the maxilla in the canine region and the width and shape of the dental follicles were registered scan by scan throughout the extension of the follicle. The width and the shape of the dental follicle of the erupting maxillary canine varied greatly. The range of the maximum width, measured from the crown to the periphery of the follicle, was 0.5-7.0 mm, with a mean of 2.9 mm and a 95% confidence interval of 2.7-3.2 mm for the entire sample. No relationship was found between the width or shape of the follicles and sex, age, stage of eruption, inclination of the canine, or width of the dental arch. However, the location of the maxillary canine vis-à-vis the adjacent incisor was significantly associated with the width of the follicle, which indicated that local anatomic conditions might influence the width and shape of the follicle. The dental follicles of the ectopically erupting canines were, on average, wider than those of the normally erupting canines. The 95% confidence interval for the normally erupting canines was 2.3-2.7 mm; for the buccally erupting canines 2.4-4.1 mm; for the lingually erupting canines 2.6-3.0 mm; and for the apically erupting canines in relation to the lateral incisors 2.9-4.1 mm. Canine follicles that were wide but within normal limits did not cause deviations in adjacent teeth. Cystically degenerated dental follicles were found but were indistinguishable on the CT scans from those that had been widened physiologically. The contributions of the studied variables to the variation in the width of the dental follicle of the maxillary canine were analyzed with regression models.