Assessment of Nonsurgical Adult Maxillary Expansion and Gingival Recession

Hypothesis: We hypothesize that there is no mean difference in gingival buccal attachment levels between pre and post-treatment for each of the non-surgically expanded adults and non-expanded adult groups. We also hypothesize that there is no mean difference between non-surgically expanded adults and non-expanded adults for all variables measured in this study: clinical crown height, transarch width, dental angulation, and palatal vault angle. Objective: To evaluate nonsurgical adult maxillary expansion and assess the gingival buccal attachment levels pre and post-treatment in adult patients with constricted arches where the maxillary arch was expanded. Methods: Initial and final study models were evaluated for 26 adults treated with nonsurgical maxillary expansion and compared with 31 adult orthodontic patients who did not require expansion. Study models were scanned and digitized with the Lythos Digital Impression System (Ormco). Linear measurements were completed in Ortho Insight 3D (clinical crown height and transarch width). Angular measurements were completed in Dolphin Imaging (dental angulation and palatal vault angle). Results: Patients who underwent nonsurgical adult expansion showed a mean increase in transarch width for first premolars (3.2+/-1.5mm), second premolars (3.1+/-1.0mm), and first molars (2.5+/-1.4mm). The expansion group showed a mean increase in clinical crown height of the right first premolar (0.5 +/- 0.7mm), right second premolar (0.4 +/- 0.6mm), left first premolar (0.4+/- 0.7mm), left second premolar (0.4 +/- 0.3mm), and left first molar (0.2 +/- 0.6mm). Conclusions: There was a mean difference in gingival buccal attachment levels post-treatment for each of the non-surgically expanded adults and non-expanded adult groups. There was a statistically significant increase between non-surgically expanded adults and non-expanded adults for clinical crown height, transarch width and dental angulation, especially in premolar areas. Despite the difference between groups, the amount of gingival buccal attachment loss was small and clinically acceptable. Funding: Dept. of Orthodontics. IRB/ACC protocol: 20150273.