3741 - A Pilot Comparative Study of Mouthbite Devices and Their Effect on Patient Experience and Treatment Setup

W. W. Tan¹, Y. L. Soong¹, N. Yit¹, A. B. Mohamed Ariffin¹, T. H. Low¹, K. M. Lee¹, S. Y. Sin¹, S. N. A. B. Rahim¹, Z. R. Master², M. L. K. Chua³, K. W. Fong⁴, S. S. Poh⁵, F. Wang¹, J. Wee⁴, K. Sommat¹, T. W. K. Tan², and E. P. P. Pang²; ¹National Cancer Centre Singapore, Singapore, Singapore, ²Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore, ³Department of Head and Neck and Thoracic Cancers, Divisions of Radiation Oncology and Medical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore, ⁴Division of Radiation Oncology, National Cancer Centre Singapore, Singapore, Singapore, ⁵National Cancer Centre, Singapore, Singapore, Singapore

Purpose/Objective(s): For head and neck (H&N) cancer radiotherapy, mouthbites play a vital role in tongue immobilization and positioning oral tissues for tissue preservation. However, the most effective commercially available mouthbite remains uncertain, leading to a gap in the literature. Additionally, theres a concerning 21% failure rate for patients requiring mouthbite in our center. This pilot study aims to compare the tolerability, ease of fabrication, and effectiveness of 2 other commercially available mouthbite devices (BL, BF) with the in-house fabricated mouthbite (RW) used in our center for H&N patients. Materials/

Methods: This prospective randomised controlled pilot study considered 30 H&N patients undergoing radiotherapy and required a mouthbite for it. There are 10 patients in each of the 3 arms. The time taken to fabricate or utilise the mouthbite for patients was recorded. At 4 different intervals, (i) day of Computed Tomography (CT) simulation, (ii) first day of treatment, (iii) midcourse of treatment, (iv) last day of treatment, patient’s pain score regarding the mouthbite was recorded. Setup reproducibility for the treatment, tongue, and mouthbite position, at time intervals (ii), (iii) and (iv) were collected. These data were compared across the 3 different mouthbite groups to determine the best suitable one for use.

Results: The mean fabrication or utilisation time for BL, BF, and RW varied at 8.2, 2, and 16.3 minutes respectively. The mean pain score on CT day for BL, BF, and RW were 1, 0, and 0, on day 1 of treatment were 0.4, 0, and 0, on the mid-treatment course were 2.3, 1.4, and 1.4, and on last day of treatment were 2.5, 2.3, 1.4 respectively. All patients in the 3 different mouthbite groups completed treatment 100%. The setup reproducibility group mean for treatment, tongue and mouthbite displacement are shown in Table 1 below:

Conclusion: Other than the shorter utilisation mouthbite time by BF, there are no statistical significances found between the mouthbites groups for the tolerability of mouthbite based on mean pain score and number of treatment fractions completed, as well as the reproducibility of mouthbite based on treatment delivery, tongue and mouthbite displacement. Based on the findings of this study, there is no evidence to suggest that any alternative mouthbite is superior to the current RW mouthbite. Further investigation is warranted in this area.

Abstract 3741 – Table 1: Setup reproducibility group mean for treatment, tongue and mouthbite displacement

Treatment Position
	S/I (cm)	L/R (cm)	A/P (cm)	Yaw (°)	Pitch (°)	Roll (°)
BF	0.027	-0.022	0	-0.13	0.29	0.04
BL	0.043	0.0067	-0.053	-0.13	0.27	0.49
RW	0.10	0.067	0.033	-0.46	0.35	0.55
Tongue Position
	S/I	L/R	A/P	Yaw	Pitch	Roll
BF	0.047	-0.04	0.04	0.0067	0.44	0.083
BL	0.11	0.023	0	-0.18	0.36	0.463
RW	0.091	0.067	0.04	-0.55	0.52	0.64
Mouthbite Position
	S/I	L/R	A/P	Yaw	Pitch	Roll
BF	0.023	-0.04	0.03	0.037	0.25	0.22
BL	0.23	0.033	-0.044	-0.43	0.78	0.37
RW	0.12	0.08	-0.02	-0.71	0.28	0.27