3D-printed individualized tooth-borne tissue retraction devices compared to conventional dental splints for head and neck cancer radiotherapy: a randomized controlled trial

Abstract

Background Despite modern treatment techniques, radiotherapy (RT) in patients with head and neck cancer (HNC) may be associated with high rates of acute and late treatment-related toxicity. The most effective approach to reduce sequelae after RT is to avoid as best as possible healthy tissues and organs at risk from the radiation target volume. Even small geometric changes can lead to a significant dose reduction in normal tissue and better treatment tolerability. The major objective of the current study is to investigate 3D printed, tooth-borne tissue retraction devices (TRDs) compared to conventional dental splints for head and neck RT. Methods In the current two-arm randomized controlled phase II trial, a maximum of 34 patients with HNC will be enrolled. Patients will receive either TRDs or conventional dental splints (randomization ratio 1:1) for the RT. The definition of the target volume, modality, total dose, fractionation, and imaging guidance is not study-specific. The primary endpoint of the study is the rate of acute radiation-induced oral mucositis after RT. The quality of life, local control and overall survival 12 months after RT are the secondary endpoints. Also, patient-reported outcomes and dental status, as well as RT plan comparisons and robustness analyzes, will be assessed as exploratory endpoints. Finally, mesenchymal stem cells, derived from the patients’ gingiva, will be tested in vitro for regenerative and radioprotective properties. Discussion The preliminary clinical application of TRD showed a high potential for reducing acute and late toxicity of RT in patients with HNC. The current randomized study is the first to prospectively investigate the clinical tolerability and efficacy of TRDs for radiation treatment of head and neck tumors. Trial registration: ClinicalTrials.gov; NCT04454697; July 1st 2020; https://clinicaltrials.gov/ct2/show/record/NCT04454697.

Oral Sequelae after Head and Neck Radiotherapy: RCT Comparing 3D-Printed Tissue Retraction Devices with Conventional Dental Splints

“…For the GUARD study, sample size calculation was performed for the incidence of oral mucositis. It was based on preliminary clinical experience with TRDs and was published as part of the study protocol [24]. A necessary number of 28 evaluable participants (14 per group) was determined to achieve a power of 80% at a significance level of 5%.…”

“…The GUARD study was designed as a non-blinded, 1:1 parallel-group randomized controlled pilot trial and approved by the local ethics committee. An a priori study protocol was pre-registered under ClinicalTrials.gov, NCT04454697, GUARD trial, on 1 July 2020 and also published [24]. A feasibility study was also published, which was carried out in preparation for the GUARD study [18] Informed consent was obtained from all eligible patients willing to participate.…”

Dual‐energy CT‐based stopping power prediction for dental materials in particle therapy

“…All these materials comprised elements of a high atomic number Z : cobalt‐chrome ( Z Co = 27, Z Cr = 24), composite I ( Z Ba = 56), composite II ( Z Yb = 70), glass‐ceramic ( Z Y = 39), lithium disilicate ( Z Zn = 30, Z Zr = 40), titanium ( Z Ti = 22), zirconium dioxide ( Z Zr = 40). Furthermore, we analyzed the single components of individualized 3D‐printed tissue retraction devices (TRDs) used to protect healthy tissue from irradiation in head and neck radiotherapy 32,33 . TRDs consist of a fixation part (made of silicone material) and a tongue retraction part (made of polymethyl methacrylate [PMMA]).…”

“…Furthermore, we analyzed the single components of individualized 3D-printed tissue retraction devices (TRDs) used to protect healthy tissue from irradiation in head and neck radiotherapy. 32,33 TRDs consist of a fixation part (made of silicone material) and a tongue retraction part (made of polymethyl methacrylate [PMMA]). Samples were fabricated into cylinders with a diameter of 2.8 cm and a length of 1−2 cm (depending on the fabrication abil-ities) (Figure 1).…”

A total inverse planning paradigm: Prospective clinical trial evaluating the performance of a novel MR-based 3D-printed head immobilization device

“…New medical applications have emerged in domains such as education, research, surgical planning, instrumentation, implants, and prostheses [4] . In RT, 3D-printing has been used for generating custom dose modulation boluses [5] , oral retractors [6] and brachytherapy applicators [7] . Growing use-cases of 3D-printing technologies pave the way for greater availability and affordability, while supporting its safety in the clinical setting.…”