Pacific Coast Society of Orthodontists Bulletin Fall 2016 - 24

PCSO Resident Research Review Alex Vo's project aimed at examining treatment effects of mandibular incisor proclination on facial and lingual alveolar bone height measurements. CBCT image files were obtained through collaboration with Dr. HeeSoo Oh at the University of the Pacific Arthur A. Dugoni School of Dentistry, where the scans had originally been obtained in an orthodontic private practice. The study used scans from 54 patients with an initial mean age of 12.8 years who underwent nonextraction orthodontic treatment. It was found that over the course of treatment, facial bone height decreased by an average of 0.95 ± 1.89 mm and lingual bone height decreased by an average of 1.30 ± 1.99 mm. Although there was an overall increase in the mandibular incisor to mandibular plane angle of 3.67 ± 5.45°, there was no correlation between the amount of proclination and changes in facial or lingual bone height. Contrary to expectations, thicker pre-treatment facial bone was correlated with greater facial vertical bone loss. This finding may be related to the results of Vanessa Brown's study, in which thicker facial bone became thinner with incisor proclination, making CBCT scans less reliable in assessing alveolar bone height. Comparing Indirect Bonding Techniques A current ongoing research topic is an assessment of indirect bonding techniques begun by Ana Castilla (Class of 2012), and recently continued by Sheila Luwiharto (Class of 2014). In this project, comparisons of bracket positioning were made after use of various indirect bonding tray transfer materials. The results of Ana's study, published in The Angle Orthodontist, demonstrated that there were mild differences in bracket positioning using various indirect bonding materials, with silicone-based methods having the greatest reliability.4 This line of investigation is ongoing, and we anticipate that interesting clinical results will be coming shortly. A complete list of these and many more interesting thesis projects completed in the graduate program at OHSU is available on our website. 24 Efforts are currently underway to publish recent studies, including those mentioned above. We anticipate that some project lines may complete their course over time, with new topics arising to keep us all on the cutting edge of orthodontic research. In conclusion, although the residents put great effort into their investigations, several faculty advisors also deserve credit in aiding project development, as these academic pursuits can truly take a village. Acknowledgements are due to Jennifer Crowe for her involvement in the resin infiltration projects, and to both her and Terry McDonald for their input on the CBCT and indirect bonding studies. Kudos to Jack Ferracane for his mentoring of the resin infiltration studies and assistance with the indirect bonding investigations, to Mansen Wang for assistance with statistical analysis, and to J. Ryan Moses and Doug Klein for their input on the indirect bonding studies. Finally, cheers to Larry Doyle, graduate program director, for his broad input on most of the research projects that are conducted in the OHSU orthodontic graduate program. Without these, and many other talented faculty members, the high-caliber research performed at OHSU could not be accomplished.  References 1. Senestraro SV, Crowe JJ, Wang M, et al. Minimally invasive resin infiltration of arrested white-spot lesions: a randomized clinical trial. J Am Dent Assoc 2013;144:997-1005. 2. Timock A, Cook V, McDonald T, Crowe J, Benninger BL, Covell DA Jr. Accuracy and reliability of buccal bone height and thickness measurements from conebeam computed tomography imaging. Am J Orthod Dentofacial Orthop 2011;140:734-744. 3. Cook V, Timock AM, Crowe JJ, Wang M, Covell DA Jr. Accuracy of alveolar bone measurements from conebeam computed tomography acquired using varying settings. Orthod Craniofac Res 2015;18:127-136. 4. Castilla AE, Crowe JJ, Moses JR, Wang M, Ferracane JL, Covell DA Jr. Measurement and comparison of bracket transfer accuracy of five indirect bonding techniques. Angle Orthod 2014;84:607-614. PCSO Bulletin  Fall 2016 http://www.ohsu.edu/xd/education/schools/school-of-dentistry/about/academic-departments/orthodontics/research.cfm

Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Fall 2016