Objective: The aim of this study was to evaluate the accuracy of three thermosensitive microsensors, which record "wear-time" of removable oral appliances (OA) used for orthodontics and obstructive sleep apnea therapy. Methods: In vitro testing was undertaken for TheraMon (Sensor T, n=20), AIR-AID SLEEP (Sensor A, n=30) and DentiTrac (Sensor D, n=16) microsensors, which were placed in a water bath to simulate "wear-time" of OA. Logs of when the microsensors were placed in the water bath were

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... pared to the time readouts from the microsensors. Trial 1 examined the accuracy of long durations of "wear" (7 hours/day). Trial 2 examined short durations of "wear" (2 hour intervals). Trial 3 tested the impact of different embedding materials on accuracy: acrylic, polyvinylchloride and thermoactive acrylic. In vivo testing included 14 volunteers who wore maxillary retainers embedded with Sensor A and D for 30 nights. Subjects' logs of appliance usage were compared to the computed readouts from the sensors. Results: In the in vitro phase, the median absolute deviation of the computed "wear-time" minus the logged time was 0.00 minutes for Sensor A and Sensor T in all trials. For Sensor D, the median deviation was 5.00 minutes in trial 1 and 3 and 10.00 minutes in trial 2. Sensor A was significantly more accurate than Sensor T and Sensor D in trial 1 (p<0.001). In trial 2, Sensor A and Sensor T were equal in accuracy but were significantly better than Sensor D (p<0.001). In trial 3, there was no effect of the material on the recording accuracies of Sensor A (p=0.13) and Sensor D (p=0.41); Polyvinylchloride was found to be significantly less accurate for Sensor T (p<0.05). In the in vivo phase, the median absolute deviation of Sensor A was 3.00 minutes and Sensor D was 5.00 minutes; there was no significant difference between Sensor A and Sensor D (p=0.45). Conclusion: Sensor D tended to have the largest deviation in recording accuracy in in vitro testing using the water bath. All three microsensors have accep [...]