University of Twente Student Theses


Retention for 3D-printed hollow immediate surgical obturators for maxillectomy patients

Coenraad, T.L. (2023) Retention for 3D-printed hollow immediate surgical obturators for maxillectomy patients.

[img] PDF
Abstract:Introduction: Retention of heavy obturators for maxillectomy patients can be challenging. Weight reduction can be achieved by hollow bulbs. A CAD/CAM workflow for a 3D-printed hollow Immediate Surgical Obturator (hISO) is developed in our centre. This workflow currently consists of data acquisition and the design of the baseplate and bulb. To implement the hISO in the clinic, retention is necessary. This study aims to provide the current 3D-printed hISO with retention. Method: The proposed workflow for 3D-printable retention clasps includes design criteria, such as a safe and solid design, sufficient retention, free gingival sulcus and cementoenamel junction, and compatibility with oral structures and the hISO. These clasps are tested in a phantom study, simulating the outward force of exudate and contracting tissue and the force on the obturator during deglutition. A study is performed to determine the tongue-palate pressure (TPP) in three locations for young, healthy females during deglutition. A classification system is proposed that guides digital bulb-shape design, with corresponding 3D-printed clasps tested for each class to determine their retention. These clasps are compared against conventional circumferential wires around teeth combined with zygomatic wire and boulder, along with assessing additional retention when used in combination with a palatal screw. The retention is measured in terms of displacement, measured with an EM navigation system. Results: The proposed NKI classification system consists of four alveolar classes and three zygomatic classes. Although the final design of the 3D-printed retention clasps met all design criteria, determining undercuts and insertion paths remained challenging, initiating exploration into a digital surveyor. TPP averages 17 kPa across anterior, medial, and posterior locations in the three subjects. According to the phantom study, the 3D-printed clasps outperform the circumferential wires around the teeth for all alveolar classes when combined with a zygomatic wire. For the zygomatic classes, retention was insufficient, which is in line with the literature. The 3D-printed clasps did not add retention in combination with a palatal screw. Conclusion - This study provides a workflow for 3D-printed retention clasps, enhancing the hISO clinical viability. The 3D-printed clasps provide sufficient retention when combined with a zygomatic wire for the alveolar classes of the NKI classification. Future research should explore alternative retention methods, such as zygomatic implants, for retention of the zygomatic classes.
Item Type:Essay (Master)
NKI-AvL, Amsterdam, Netherlands
Faculty:TNW: Science and Technology
Subject:44 medicine, 50 technical science in general
Programme:Technical Medicine MSc (60033)
Link to this item:
Export this item as:BibTeX
HTML Citation
Reference Manager


Repository Staff Only: item control page