Dataset Information

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 1^st 2020; https://clinicaltrials.gov/ct2/show/record/NCT04454697 .

SUBMITTER: Held T

PROVIDER: S-EPMC8052727 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundRadiotherapy for head and neck cancer may cause various oral sequelae, such as radiation-induced mucositis. To protect healthy tissue from irradiation, intraoral devices can be used. Current tissue retraction devices (TRDs) have to be either individually manufactured at considerable cost and time expenditure or they are limited in their variability. In this context, a 3D-printed, tooth-borne TRD might further facilitate clinical use.MethodsA novel approach for the manufacturing of TRDs is described and its clinical application is analysed retrospectively. The devices were virtually designed for fabrication by 3D-printing technology, enabling-in only a single printing design-caudal or bi-lateral tongue displacement, as well as stabilization of a tongue-out position. For a total of 10 patients undergoing radiotherapy of head and neck tumors, the devices were individually adapted after pre-fabrication. Technical and clinical feasibility was assessed along with patient adherence. Tissue spacing was calculated by volumetric analysis of tongue retraction. In one exemplary case, radiotherapy treatment plans before and after tissue displacement were generated and compared. The reproducibility of maxillomandibular relation at device re-positioning was quantified by repeated intraoral optical scanning in a voluntary participant.Results3D-printing was useful for the simplification of TRD manufacture, resulting in a total patient treatment time of less than 30 min. The devices were tolerated well by all tested patients over the entire radiation treatment period. No technical complications occurred with the devices. The TRDs caused an effective spacing of the healthy adjacent tissue, e.g., the tongue. Position changes of maxillomandibular relation were limited to a mean value of 98.1 µm ± 29.4 µm root mean square deviation between initial reference and follow-up positions.ConclusionsThe presented method allows a resource-efficient fabrication of individualized, tooth-bourne TRDs. A high reproducibility of maxillomandibular relation was found and the first clinical experiences underline the high potential of such devices for radiotherapy in the head and neck area.

Project description:BackgroundPrecise orthognathic surgical splints are important in surgical-orthodontic treatment. This study aimed to propose a standardized protocol for three-dimensional (3D)-printed splints and assess the precision of splints with different occlusal coverage on the dentition (occlusal coverage depth, OCD), thus optimizing the design of 3D-printed splints to minimize the seemingly unavoidable systematic errors.MethodsResin models in optimal occlusion from 19 patients were selected and scanned. Intermediate splints (ISs) and final splints (FSs) with 2-mm, 3-mm, 4-mm, and 5-mm OCDs were fabricated and grouped as IS-2, IS-3, IS-4, IS-5, FS-2, FS-3, FS-4, and FS-5, respectively. The dentitions were occluded with each splint and scanned as a whole to compare with the original occlusion. Translational and rotational deviations of the lower dentition and translational deviations of the landmarks were measured.ResultsFor vertical translation, the lower dentitions translated inferiorly to the upper dentition in most of the splints, and the translation increased as OCD got larger. Vertical translations of the dentitions in 89.47% of IS-2, 68.42% of IS-3, 42.11% of IS-4, 10.53% of IS-5, 94.74% of FS-2, 63.16% of FS-3, 26.32% of FS-4, and 21.05% of FS-5 splints were below 1 mm, respectively. For pitch rotation, the lower dentitions rotated inferiorly and posteriorly in most groups, and the rotation increased as OCD got larger. Pitch rotations of the dentitions in 100% of IS-2, 89.47% of IS-3, 57.89% of IS-4, 52.63% of IS-5, 100.00% of FS-2, 78.95% of FS-3, 52.63% of FS-4, and 47.37% of FS-5 splints were below 2°, respectively. On the other hand, the transversal and sagittal translations, roll and yaw rotations of most groups were clinically acceptable (translation < 1 mm and rotation < 2°). The deviations of ISs and FSs showed no statistical significance at all levels of coverage (P > 0.05).ConclusionsA protocol was proposed to generate 3D-printed ISs and FSs with normalized basal planes and standardized OCDs. Deviations of the ISs and FSs were more evident in the vertical dimension and pitch rotation and had a tendency to increase as the OCD got larger. ISs and FSs with both 2-mm and 3-mm OCD are recommendable regarding the precision relative to clinical acceptability. However, considering the fabrication, structural stability, and clinical application, ISs and FSs with 3-mm OCD are recommended for accurate fitting.

Project description:ObjectiveThe main objective is to evaluate the effectiveness of en masse retraction with temporary skeletal anchorage devices (TSADs) versus two-step retraction with conventional anchorage (CA) in terms of the skeletal, dental, and soft-tissue variables, as well as the duration of retraction or overall orthodontic treatment.Materials and methodsAn electronic search of PubMed and nine other major databases for prospective, randomized controlled trials (RCTs) and clinical controlled trials (CCTs) was carried out between January 1990 and April 2018. The bibliography in each identified article was checked out. In addition, manual searching was performed in the same time frame in five major orthodontic journals. Adult patients undergoing fixed orthodontic treatment with extraction of maxillary premolars followed by an en masse retraction in the experimental group and two-step retraction of upper anterior teeth in the control group. Methodological index for nonrandomized studies for CCTs and Cochrane's risk of bias tool for RCTs were applied.ResultsFour articles (two RCTs and two CCTs) were included in this review and all articles were appropriate for the quantitative synthesis. There was no significant difference between the en masse retraction and two-step retraction groups in terms of SNA, SNB, ANB, and MP-SN angles. Using TSADs gave significantly better results in terms of posterior anchorage and incisors inclination, and greater anterior teeth retraction in comparison with CA (standardized mean difference [SMD] = -3.03 mm, P < 0.001; SMD = 0.74°, P = 0.003; SMD = -0.46 mm, P = 0.03, respectively). En masse/TSAD combination caused a significantly greater increase in nasolabial angle, higher decrease in facial convexity angle, and greater lower lip retraction in comparison with two-step/CA combination (weighted mean difference = 4.73°, P = 0.007; P = 0.0435; SMD = -0.95 mm, P = 0.01, respectively).ConclusionThere is weak-to-moderate evidence that using either en masse/TSAD combination or two-step/CA combination would lead to similar skeletal improvement. There is a very weak-to-moderate evidence that using TSADs with en masse retraction would cause better posterior anchorage and incisors inclination, and greater anterior teeth retraction than using CA with two-step retraction. There is weak-to-moderate evidence that using en masse/TSAD combination would lead to a better improvement in the facial profile. According to the quality of evidence, we confirm the need for more well-conducted RCTs in the en masse retraction field.