Pilot in-vitro study on insertion/removal performance of hand-cast, milled and 3D printed splints

Objectives: The aim of this in-vitro pilot study was to establish a splint testing method and compare insertion/removal performance of dental splints. Materials and methods: 56 identical lower jaw splints (n = 8 per group) were manufactured from 2x methacrylate (MA) hand-cast (reference material), deep-drawn Polyethyleneterephthalate, combined deep-draw MA handcast, 2x CAD/CAM-milled MA and 3D-printed MA systems. After 10 days water storage (37 degrees C), cyclic pull-off and insertion performance on a metal jaw was investigated. Statistics; Shapiro-Wilk-test, one-way-ANOVA; post-hoc-Bonferroni, Kaplan-Meier-survival, alpha = 0.05. Results: Mean insertion/pull-off cycles varied significantly (p = 0.000) between 864 cycles (MA) and 202640 cycles (Deep Draw MA). Fracture of the splints was characterized by brittle individual fractures in the 31-34 region and most fractures in region 35 (44 of 56 splints). Finite element analysis confirmed the type and location of failure. Conclusions: Deep-draw, cast methacrylate and combined systems showed longer insertion/pull-off system cycles in comparison to printed or milled splints. Insertion/pull-off performance showed differences between the tested splint systems and indicates the influence of the processing. Clinical relevance: The presented in-vitro test allowed for estimating the clinical insertion/pull-off performance of dental splints.

Automated summary

The study aimed to establish a splint testing method and compare the insertion and removal performance of dental splints in-vitro. Results showed significant differences in insertion/pull-off cycles between different materials, with deep-drawn, cast, and combined systems performing better compared to printed or milled splints.