Anterior Open Bite Treatment With Bonded Spurs Associated With Build-ups Versus Conventional Bonded Spurs: a Randomized Clinical Trial.

Anterior open bite is commonly related with lower anterior face height increase. Some early treatment protocols use appliances that control deleterious habits associated to appliances that produce control of the vertical dimension. Usually, these appliances (chincup, removable orthopedics) depend on patient's collaboration. Recently, the efficiency and stability of anterior open bite treatment with resin blocks bonded to the posterior teeth (build-ups) associated with fixed orthodontic appliances was described. They could be considered as a promissory alternative for vertical control during anterior open bite treatment. Then, it could be thought that the association of bonded spurs with posterior build-ups, instead of chincup, would produce vertical control during anterior open bite early treatment without the need of patient collaboration. Therefore, the aim of this study is to compare the dentoalveolar and skeletal effects of bonded spurs associated with build-ups versus conventional bonded spurs in the early treatment of anterior open bite patients.

For this, patients will be recruited at the Orthodontic Clinic of Bauru Dental School, University of São Paulo, Brazil. Fifty patients between 7 and 11 years old diagnosed with anterior open bite greater than 1 mm will be prospective and randomly allocated in one of the two study group. The experimental group will consist of 25 patients treated with bonded spurs associated with build-ups. Control group will consist of 25 patients treated with conventional bonded spurs.

Lateral radiographs and digital dental models will be obtained at the beginning (T1), 12 months after treatment (T2), and 24 months after treatment (T3). Dentoalveolar and skeletal variables will be evaluated from the lateral radiographs in the Dolphin® software. Dental casts will be analyzed with the Orthoanalyzer® software to evaluate dentoalveolar anterior vertical development, posterior teeth inclinations and arch dimensions. Superimposition of digital dental models will be performed to evaluate the relative three-dimensional dentoalveolar changes on the maxillary and mandibular arches. Discomfort, pain and quality of life will be evaluated using questionnaires.

After verifying the normal distribution, intergroup comparisons (T1 vs T2 and T1 vs T3) will be performed with t test and intragroup comparisons with dependent t test. Results will be considered statistically significant at P<0.05.

The possible harms that could appear with these therapies are related to temporary tongue discomfort during the first days after the installation of the appliances. Patients and parents will be informed that is it normal. Although it has been reported that the discomfort is temporary and transitory and usually patients adapted to the treatment after 3-5 days, patients or parents will be able to stop the treatment at any moment.