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Thesis
Salivary microbiome and host immune changes in patients treated with fixed orthodontic therapy- a longitudinal prospective cohort
University of Iowa
Master of Science (MS), University of Iowa
Spring 2025
DOI: 10.25820/etd.007875
Abstract
Background
Approximately 4.5 million Americans pursue orthodontic treatment annually for esthetic and functional benefits. However, orthodontic therapy poses risks, including compromised oral hygiene, increased susceptibility to caries, gingival inflammation, and recession, all of which are influenced by host-microbial interactions. This study aims to longitudinally evaluate the effects of fixed orthodontic therapy (FOT) on the oral microbiome and the associated host immune response though saliva sampling.
Methods
Twenty-five healthy adolescents undergoing fixed orthodontic treatment were enrolled. Saliva was collected at multiple time points, including baseline, 3 months, 6 months, 12 months, 18 months, debonding, and the 3-month retention check. To date, data analysis has been limited to seven participants with samples available through the retention period. Bacteria DNA was isolated from the saliva and 16rRNA gene was amplified and used in species identification. Cytokine and chemokine levels were isolated from the saliva and were quantified using multiplex assays. Longitudinal changes were assessed using Shannon-entropy for alpha diversity, sPLS-DA analysis, and spline modeling.
Results
Fixed orthodontic therapy was associated with significant shifts in microbial profiles at different timepoints throughout treatment, as well as changes in cytokines and chemokines across treatment stages, with distinct patterns observed in the salivary environment. The microbiome returned to levels more reflective of baseline by 3 months post-debond. Whereas the cytokine and chemokine levels were returning to baseline but, not yet reflective of baseline levels by 3-month retention.
Conclusion
These preliminary findings indicate that FOT induces dynamic and environment-specific biome and immunological changes, reflecting the host’s adaptive response to treatment. Continued analysis of the remaining 18 samples will provide a more comprehensive understanding of the shifts during orthodontic therapy. These results highlight the importance of monitoring bacterial changes as well as immune responses to improve patient outcomes and inform personalized therapeutic strategies.
Keywords
Oral microbiome, host immune response, orthodontic treatment, fixed orthodontic appliances, saliva, cytokine(s), periodontal disease, caries
Details
- Title: Subtitle
- Salivary microbiome and host immune changes in patients treated with fixed orthodontic therapy- a longitudinal prospective cohort
- Creators
- Abigail Wieland
- Contributors
- Sukirth Ganesan (Advisor)Lina M Moreno Uribe (Committee Member)Shareef Dabdoub (Committee Member)Shankar Rengasamy Venugopalan (Committee Member)Michael A Callan (Committee Member)Kyungsup Shin (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Orthodontics
- Date degree season
- Spring 2025
- DOI
- 10.25820/etd.007875
- Publisher
- University of Iowa
- Number of pages
- x, 87 pages
- Copyright
- Copyright 2025 Abigail Wieland
- Language
- English
- Date submitted
- 04/29/2025
- Description illustrations
- illustrations, tables, graphs
- Description bibliographic
- Includes bibliographical references (pages 77-87).
- Public Abstract (ETD)
- In the United States, millions of Americans seek out orthodontic treatment annually. Often times, these people are seeking enhancing esthetic outcomes from care. Sometimes, however, there can be consequences to orthodontics that need to be discussed and addressed. Having straight teeth comes, frequently, with braces. Braces increase accumulation of plaque, making oral hygiene practices more challenging. With this, oral diseases like periodontal disease and cavities can arise. To understand this risk, on a biological level, our study is evaluating multiple adolescents throughout treatment. We collect their saliva multiple times during treatment and evaluating the bacteria and immune system response at each time point. We want to understand how braces change the oral environment to support health or dysfunction. We found that the bacteria in the mouth changed during treatment to become unhealthier but, by three months after treatment, the oral environment was more reflective of health. The immune system was slower to recover following treatment, however, movement toward baseline is still evident at 3 months after treatment. This shows that the mouth is resilient, and that braces do not necessarily have a long-term negative effect.
- Academic Unit
- Orthodontics; Craniofacial Anomalies Research Center
- Record Identifier
- 9984831125802771
Metrics
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