Orthodontic considerations for impacted and ectopic teeth.

This review article describes the changing approach to the management of various impacted teeth. Currently, more third molars are being retained, and it is likely that more patients will develop impactions than a generation ago because of non-extraction orthodontic treatment plans. There are still valid reasons for the surgical removal of selected third molars during the teenage years, during which time impaction can be anticipated to avoid the higher rate of morbidity associated with later removal. Palatally-impacted canines (PIC] can now often be managed with interceptive and non-surgical approaches, which are attractive options. The various approaches addressed in the literature are discussed.

Comparison of surgical and non-surgical methods of treating palatally impacted canines. I. Periodontal and pulpal outcomes.

BACKGROUND: Inferior periodontal and pulpal outcomes may follow surgical exposure of palatally impacted maxillary canines. OBJECTIVES: To compare the periodontal and pulpal health of palatally impacted maxillary canines following either surgical exposure and assisted eruption (SE) or unassisted eruption following extraction of the overlying deciduous canine and orthodontic creation of space in the arch (OT). METHODS: Twenty-eight subjects (OT group: N = 14; SE group: N = 14) with unilateral palatally impacted canines were examined at least six months after orthodontic treatment. The gingival index score, plaque index score, pocket depth, attachment loss, tenderness to percussion, pulpal responses to stimuli and radiographic assessment of changes in the pulpal cavities and peri-radicular areas were collected on the maxillary canines, lateral incisors and premolars. The contralateral teeth were used as controls. RESULTS: There were no significant differences in the plaque index scores, the gingival index scores or the periodontal outcomes between the impacted canines in the two groups (SE and OT). More impacted canines than control canines had lost some periodontal attachment in the SE group (p = 0.004). Although more lateral incisors, canines and premolars on the impacted side had partially obliterated pulps than the corresponding teeth on the control side, the teeth in both groups had similar pulpal responses (p = 0.064). CONCLUSIONS: Natural eruption and conservative surgical exposure with orthodontic alignment have minor effects on the periodontium. Impacted canines treated surgically and non-surgically had a higher prevalence of pulpal changes than the control canines. Ultimately, the choice of treatment may depend on the clinical indications, the patient's and the orthodontist's preferences.

Comparison of surgical and non-surgical methods of treating palatally impacted canines. II. Aesthetic outcomes.

BACKGROUND: Palatally impacted maxillary canines may appear unsightly after treatment because of changes in position and colour. AIM: To determine if palatally impacted canines treated either by surgical exposure and orthodontic repositioning or by creation of space in the arch and unassisted eruption have different aesthetic outcomes. METHODS: Twenty eight subjects with unilateral palatally impacted canines who had completed orthodontic treatment at least 6 months previously were recruited from three specialist practices. In 14 subjects the canines had been treated by surgical exposure, orthodontic extrusion and repositioning in the arch (SE group) and in the remainder the deciduous canines were extracted and excess space created in the arch for the canines to erupt naturally (OT group). The contralateral canines were used as controls. The mean pretreatment ages of the subjects in the SE and OT groups were 13.5 (SD:1.6) years and 13.5 (SD:1.3) years respectively. The position and colour of the canines were assessed on post-treatment study models and 35 mm slides using the American Board of Orthodontics Objective Grading System (ABO OGS) and subjective appraisal by two orthodontists. Each subject used a semantic scale to rate the aesthetic outcome of treatment. RESULTS: Sixty four per cent of the treated canines in the SE group were significantly more 'intruded' than the treated canines in the OT group (p = 0.004) and the control canines (p = 0.004). The ABO OGS grades of the canines in the SE and OT groups were similar (p = 0.173). While the assessors detected a lack of labial root torque and gingival margin changes in the canines in the SE group, the subjects in both groups were satisfied with the appearance of the canines post-treatment. CONCLUSIONS: Palatally impacted canines treated by surgical exposure, extrusion and orthodontic treatment were more likely to be displaced vertically ('intruded') after treatment than palatally impacted canines treated by extraction of the overlying deciduous canines and creation of excess space in the arch. Small occlusal and aesthetic changes detected by the orthodontists, but not the ABO OGS, did not appear to detract from the satisfaction of the subjects with the results of orthodontic treatment.

Factors influencing the non-surgical eruption of palatally impacted canines.

BACKGROUND: Many palatally impacted canines in children do not require surgical exposure prior to the start of orthodontic treatment. They erupt in mid-alveolar positions providing excess space is made for them in the arch. The time required for an impacted tooth to emerge under these conditions is highly variable. AIM: To determine the factors influencing the time required for a palatally impacted canine to spontaneously disimpact following orthodontic treatment to create excess space in the arch. METHOD: Thirty palatally impacted canines, which emerged following orthodontic treatment to open excess space in the arch, were used. The impacted teeth were present in 28 children. No canines were surgically exposed. The positions of the impacted canines before treatment, the mesiodistal widths and rotations of the adjacent and contralateral lateral incisors, age and gender of the subjects, subjects' dental ages, presence of either incisor or premolar hypodontia, number of subjects with bilaterally impacted canines, and number of siblings with impacted canines were recorded. Canines that erupted in less than nine months of treatment were compared with canines that required more than nine months of treatment. The canines were grouped by severity of impaction (sectors II - IV) and compared. RESULTS: There were significantly more severe (sector IV) impactions in the long duration group compared with the short duration group. Significantly more cases of incisor-premolar hypodontia were found in the short duration group. Canines impacted in sector IV emerged after 21 months of treatment and canines in sectors II and III emerged after eight months of treatment. Lateral incisors adjacent to the impacted teeth were rotated mesiolabially to a greater extent in the sector IV group compared with lateral incisors in the sector II group. Differences in rotation of the adjacent and contralateral lateral incisors were significantly less in the sector II group compared with the lateral incisors in the sector III and IV groups. CONCLUSIONS: The sector of impaction was the best guide to the duration of treatment prior to emergence.

A longitudinal index study of orthodontic stability and relapse.

BACKGROUND: Previous studies of stability and relapse after orthodontic treatment report short-term stability is generally followed by slow relapse to the original condition. What these studies do not report is whether this relapse is continuous or interspersed with periods of improvement or stability. METHODS: A subjective 0-10 index of malocclusion was used to record post-treatment stability and relapse over 10 to 12 years following fixed appliance orthodontic treatment of 24 patients. The severity scores were plotted on timelines. RESULTS: Episodes of change, both favourable and unfavourable, were interspersed with episodes of stability. CONCLUSIONS: Changes in the first 3 and 12 months post-treatment are indicative of the 10 to 12 years post-treatment outcomes. This index may provide a useful instrument to analyze patients and/or their study models longitudinally.

Orthodontic treatment of palatally impacted maxillary canines.

The aim of this study was to determine the feasibility of treating children with impacted maxillary canines by orthodontic treatment alone. The subjects were 28 children (mean age: 13.5 years, range 11.4-16.1 years) with between them 32 palatally impacted canines. The overlying primary canines were extracted between 0 and 42 months before the start of appliance treatment to open space in the arches for the impacted teeth. No other surgical procedures were carried out prior to the start of appliance treatment. Appliance treatment was deferred for at least six months if an impacted canine was the main reason for treatment, otherwise treatment was commenced according to the needs of the patient. In 94% of the cases, the severity of impaction lessened following extraction of the overlying primary canines and orthodontic treatment. The deepest impactions tended to occur in the oldest children. The majority (75%) of the canines emerged following orthodontic treatment to create space for them in the arch; the remainder were surgically exposed. Appliance treatment tended to take longer in children with the deepest impactions. It is concluded that fixed appliance treatment to create space for a palatally impacted canine is an effective management option for children with impacted maxillary canines.