Evaluation of Optical Coherence Tomography in Dentistry

Optical coherence tomography (OCT) is a medical diagnostic tool, providing non-invasive, non-radiative and high resolution imaging. OCT has been established since many years in ophthalmology. In dentistry the diagnostic potential of OCT is currently increasingly being noticed. This clinical study includes two individual trials: (i) Longitudinal assessment of surface sealant thickness using optical coherence tomography and (ii) comparison of crevicular fluid levels of inflammatory cytokines after the application of surface sealants.

Trial 1: Evaluation of the abrasion behavior of the orthodontic surface sealants Pro Seal®, Opal®Seal, and Protecto®CaF2Nano. The quadrants of 20 participants will be randomly assigned to four study groups. Using a split mouth design three commonly used orthodontic surface sealants (Pro Seal®, Opal®Seal, and Protecto®CaF2Nano) and a bonding primer (Transbond XT) which is used as a control will be applied to the labial surfaces of the teeth of the respective quadrants. The thickness changes of the orthodontic surface sealants and the development of enamel demineralization will be monitored at the day of the application and five additional time points (t1= 1 month, t2= 3 months, t3= 6 months, t4=9 months, t5= 12 months) using OCT. Trial 2: Evaluation of Adverse effects of orthodontic surface sealants. 15 quadrants of the trial group described above (Trial1) will be randomly selected and gingival crevicular fluid (GCF) will be sampled in the respective quadrants at the day of bracket bonding prior (t0) and at three additional time points (t1= 30 min, t2= 60 min, t3= 90 min) after the application of surface sealants or the bonding primer, respectively. Analysis will be performed using magnetic Luminex screening assays for IL-8 (Interleukin 8), and IL-10 (Interleukin 10) and examined for inflammatory cytokines after the application of surface sealants.

Application of different orthodontic surface sealants to participants: Randomly assigned quadrants in this arm will receive a bonding primer (Transbond XT) The investigators will evaluate in this arm the development of demineralization its adverse effects after application

Application of different orthodontic surface sealants to participants: Randomly assigned quadrants in this arm will receive an orthodontic surface sealant (Protecto®CaF2Nano). The investigators will evaluate in this arm its abrasion behavior and the development of demineralization its adverse effects after the application

Application of different orthodontic surface sealants to participants: Randomly assigned quadrants in this arm will receive an orthodontic surface sealant (Pro Seal®). The investigators will evaluate in this arm its abrasion behavior and the development of demineralization its adverse effects after the application

Application of different orthodontic surface sealants to participants: Randomly assigned quadrants in this arm will receive an orthodontic surface sealant (Opal®Seal). The investigators will evaluate in this arm its abrasion behavior and the development of demineralization its adverse effects after the application

Application of • Transbond XT (activator comparator) to labial surfaces of teeth of randomized quadrants.

Application of • Protecto®CaF2Nano (orthodontic surface sealant) to labial surfaces of teeth of randomized quadrants.

Application of • Protecto®CaF2Nano (orthodontic surface sealant) to labial surfaces of teeth of randomized quadrants.

Application of • Opal®Seal (orthodontic surface sealant) to labial surfaces of teeth of randomized quadrants.

The thickness changes of the orthodontic surface sealants and the development of enamel demineralization will be monitored at the day of the application and five additional time points (t1= 1 month, t2= 3 months, t3= 6 months, t4=9 months, t5= 12 months)

To evaluate possible adverse effects of orthodontic surface sealants in vivo gingival crevicular fluid will be sampled in the respective quadrants at the day of bracket bonding prior (t0) and at three additional time points (t1= 30 min, t2= 60 min, t3= 90 min) after the application of surface sealants or the bonding primer. Existing data on possible adverse effects of resin monomers from restorative composites or surface sealants were obtained using 3D tissue models; therefore, in the present study the investigators will attempt to evaluate possible adverse effects of commonly used smooth surface sealants on gingival tissues by analysing inflammatory cytokines in crevicular fluid of the participants after the application of surface sealants.To this end, the levels of the inflammatory cytokines (IL-8 (Interleukin 8), and IL-10 (Interleukin 10) in GCF will be assessed using multiplex analysis.

To assess cytokine levels GCF will be sampled at the day of bracket bonding prior (t0) and at three additional time points (t1= 30 min, t2= 60 min, t3= 90 min) after the application of surface sealants or the bonding primer, respectively.

Inclusion Criteria: Orthodontic treatment need Informed consent from all patients and their parents or legal guardians after explaining of the study Exclusion Criteria: • withdrawn consent

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