Three dimensional evaluation of alveolar bone changes in response to different rapid palatal expansion activation rates.

Brian Lablonde,Katherine Kula,Manuel Lagravere Vich,Paul Edwards,Ahmed Ghoneima

doi:10.1590/2177-6709.22.1.089-097.oar

Brian Lablonde, Katherine Kula + Show 3 more

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https://doi.org/10.1590/2177-6709.22.1.089-097.oar

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Abstract

ABSTRACTIntroduction: The aim of this multi-center retrospective study was to quantify the changes in alveolar bone height and thickness after using two different rapid palatal expansion (RPE) activation protocols, and to determine whether a more rapid rate of expansion is likely to cause more adverse effects, such as alveolar tipping, dental tipping, fenestration and dehiscence of anchorage teeth. Methods: The sample consisted of pre- and post-expansion records from 40 subjects (age 8-15 years) who underwent RPE using a 4-banded Hyrax appliance as part of their orthodontic treatment to correct posterior buccal crossbites. Subjects were divided into two groups according to their RPE activation rates (0.5 mm/day and 0.8 mm/day; n = 20 each group). Three-dimensional images for all included subjects were evaluated using Dolphin Imaging Software 11.7 Premium. Maxillary base width, buccal and palatal cortical bone thickness, alveolar bone height, and root angulation and length were measured. Significance of the changes in the measurements was evaluated using Wilcoxon signed-rank test and comparisons between groups were done using ANOVA. Significance was defined at p ≤ 0.05.Results: RPE activation rates of 0.5 mm per day (Group 1) and 0.8 mm per day (Group 2) caused significant increase in arch width following treatment; however, Group 2 showed greater increases compared to Group 1 (p < 0.01). Buccal alveolar height and width decreased significantly in both groups. Both treatment protocols resulted in significant increases in buccal-lingual angulation of teeth; however, Group 2 showed greater increases compared to Group 1 (p < 0.01).Conclusion: Both activation rates are associated with significant increase in intra-arch widths. However, 0.8 mm/day resulted in greater increases. The 0.8 mm/day activation rate also resulted in more increased dental tipping and decreased buccal alveolar bone thickness over 0.5 mm/day.

Highlights

The aim of this multi-center retrospective study was to quantify the changes in alveolar bone height and thickness after using two different rapid palatal expansion (RPE) activation protocols, and to determine whether a more rapid rate of expansion is likely to cause more adverse effects, such as alveolar tipping, dental tipping, fenestration and dehiscence of anchorage teeth
The results demonstrated that both activation rates increased intra-arch widths with the greatest amount of increase occurring more posteriorly and less expansion occurring across the canines; activating 0.8 mm/day resulted in greater increases compared to activating 0.5 mm/day
There is lack of literature describing the changes in buccal bone and potential root resorption due to different rates of activation of RPE that are commonly used in the practice of orthodontics

Summary

Introduction

The aim of this multi-center retrospective study was to quantify the changes in alveolar bone height and thickness after using two different rapid palatal expansion (RPE) activation protocols, and to determine whether a more rapid rate of expansion is likely to cause more adverse effects, such as alveolar tipping, dental tipping, fenestration and dehiscence of anchorage teeth. Results: RPE activation rates of 0.5 mm per day (Group 1) and 0.8 mm per day (Group 2) caused significant increase in arch width following treatment; Group 2 showed greater increases compared to Group 1 (p < 0.01). Buccal alveolar height and width decreased significantly in both groups Both treatment protocols resulted in significant increases in buccal-lingual angulation of teeth; Group 2 showed greater increases compared to Group 1 (p < 0.01). Rapid palatal expansion (RPE) is a therapeutic orthodontic treatment used to address deficiencies of the maxilla in the transverse dimension such as bilateral crossbite and constricted maxilla, as well as to increase dental arch perimeter in patients with tooth-size and arch-length discrepancies.[1,2] Palatal expanders are frequently 2- or 4-banded trans-palatal appliances that expand the maxillary arch via a jackscrew mechanism that the patient turns according to the orthodontist’s activation protocol. The widest portion of skeletal expansion is seen at the anterior nasal spine and diminishes posteriorly towards the posterior nasal spine.[9,11,12]

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