Expose and Bonding of Unerupted Posterior Teeth

Impacted teeth requiring the intervention of orthodontic treatment is a clinical situation often seen in children and adolescent population. When the anterior teeth (central incisors, lateral incisors, canines) are impacted the most common treatment choice is surgical exposure of the tooth and bonding of an orthodontic bracket.^1,2 This often referred to as simply expose and bond (E&B). This process allows for controlled traction to be applied to the tooth to facilitate moving the tooth into the oral cavity. This recognised treatment strategy has good success and produces appropriate results especially with good case selection. Unfortunately the same approach is not commonly practiced for impactions related to posterior teeth. There remains little evidence on the level of success if such an approach is taken and clinicians generally appear to have a guarded and negative view. This study was aimed to review the outcomes for E&B of posterior teeth.

Retrospectively the electronic operations log was reviewed searching for all patients requiring E&B of teeth between 2011-2014. From the available cohort, patient’s clinical records were reviewed. Only patients undergoing E&B of a posterior tooth (1^st premolar to 3^rd molar) were included for analysis in this review. Further inclusion criteria included evidence the tooth was unerupted and more than 6 months past the accepted eruption age. Only patients jointly treatment planned by orthodontics and oral surgery on the multi-disciplinary clinic were included. Data was collected from clinical records and included patient demographics as well as surgical and orthodontic factors.

A total of 19 patients had undergone E&B involving 26 posterior teeth. The male to female ratio was 13:6 with a mean age of presentation of 16.3 years (range: 13-32 years). The most common tooth undergoing E&B was the 2^nd premolar (mandibular 12:6 maxillary). First and second premolars (23/26 cases) dominated the cohort while the remaining teeth were all 2^nd molars (mandibular 2:1 maxillary).

Impaction against an adjacent tooth accounted for 10/19 of the patients with primary failure of eruption the cause in 7 patients. The remaining 2 patients where due to a dentigerous cyst and cleidocrainial dysplasia. Six cases had pre-operative CBCT for the purpose of treatment planning. All procedures were treated via a closed E&B approach.

Of the 26 teeth, 24 (92%) where successfully extruded into the oral cavity. Both unsuccessful cases showed no movement after 9 months of traction and had an original diagnosis of primary failure of eruption. Both these cases were subsequently treatment planned for extraction of which one cases showed ankylosis at this stage. Interestingly the remaining 5 cases of primary failure of eruption were all successfully brought into the oral cavity and were all mandibular second premolars. Of the successful cases the average age at presentation was 15.7 years (range: 13-18 years). The mean age in the sub-cohorts of the successful premolars was 15.8 years (n=22) and this decreased to 15.1 years when considering only the successful lower premolars (n=14).

E&B of posterior teeth, if correctly identified, can carry high success with second premolar being good candidates. Such cases should be managed jointly between orthodontics and oral surgery to consider all aspects. As with E&B in anterior teeth, success appears to be greater when the procedure is carried out in the younger patient.

 Reference

 

1. https://www.rcseng.ac.uk/fds/publications-clinical-guidelines/clinical_guidelines/documents/ManMaxIncisors2010.pdf
2. https://www.rcseng.ac.uk/fds/publications-clinical-guidelines/clinical_guidelines/documents/ManPalEctMaxCan2010.pdf