Inflammation in Clear Aligners With and Without Attachments

Detailed Study Protocol:

This pilot clinical study will recruit subject currently undergoing orthodontic therapy in the graduate orthodontic residency program at the UNMC College of Dentistry. Each subject will be screened for recruitment into the study by review of records by study personnel to determine qualifications regarding inclusion and exclusion criteria. Once the subject has been screened, the subject (if over 18 years old) or the subjects' parent (if subject is between 14-18 years old) will be introduced to the study and invited to participate. The consent form will be reviewed, all questions answered and informed consent obtained prior to data collection. Study groups will consist of 15 subjects per group. Group A will be comprised of 15 subjects undergoing clear aligner orthodontic therapy with bonded composite attachments on the first molars. Group B will be comprised of 15 subjects undergoing clear aligner therapy without attachments on the first molars. The decision whether or not to use aligners is not a study decision and is part of routine orthodontic treatment planning and care. Routine aligner protocol includes a 1 week change schedule (aligner trays are changed/switched weekly) and must be worn a minimum of 22 hours/day. At the single data collection appointment, data collection will include assessment of plaque presence/absence at the mesiobuccal site of the first molars, gingival crevicular fluid (GCF) collection at the mesiobuccal site of the first molars, Gingival Index (Loe \& Silness) assessment at the mesiobuccal of each first molar (visual determination of gingival inflammation), probing depth assessment at the mesiobuccal of each first molar, and bleeding on probing (BOP) assessment at the mesiobuccal of the first molars. These measurements are being done for study purposes only.

The GCF collection procedure includes isolation of the tooth with cotton rolls, followed by gentle removal of all supragingival plaque with a dental explorer instrument. A small paper point will be inserted into the mesiobuccal gingival sulcus and held for 30 seconds to absorb the GCF. Four samples will be taken from each patient, one sample from each first molar. All samples will be stored at -80 degrees Celsius until assay.

Statistical analysis will be completed via t-tests and modeling. Within-patient differences will be calculated by subtracting the inflammatory marker value from a tooth without an attachment from a tooth with an attachment. These differences within patients will be averaged across all patients and compared to a null value of zero using a one sample t-test to see if the difference is statistically significant (this is the same as a paired t-test). This will be done for multiple inflammatory markers of interest, with IL1beta as the primary outcome of interest. As secondary, exploratory analyses, these difference scores will be compared to variables of interest (e.g., age, sex, length of time in a clear aligner, etc.), to see if there are associations with the size of differences observed, using Pearson or Spearman correlations for continuous variables, or Wilcoxon rank sum or Kruskal Wallis test

The primary outcome will be measure of inflammatory biomarker levels in GCF from first molars; specifically IL-1B. IL-6, TNF-alpha, MMP-8 will be measured as secondary outcomes. All biomarkers will be measured in pg/µL.

Additional outcomes will include assessment of periodontal clinical parameters (plaque presence, Gingival index, BOP, probing pocket depth (PD).