Clinical evaluation of tissue stops on 3D-printed custom trays

Kehui Deng,Linlin Li,Rong Li,Yong Wang,Hu Chen,Yongsheng Zhou,Yuchun Sun

doi:10.1038/s41598-018-37826-7

Abstract

This study evaluated the quality of impressions taken using three-dimensional (3D)-printed custom trays with different tissue stops to optimize the custom tray designs. Different custom trays were designed and printed based on six edentulous patients. These trays were divided into four groups based on the tissue-stop designs: 3DP trays (3D-printed trays without tissue stops), 3DPS trays (3D-printed trays with saddle-shaped tissue stops), 3DPM trays (3D-printed trays with marginal-band tissue stops) and 3DPIM trays (3D-printed trays with inner marginal-band tissue stops). Final impressions were taken using these trays, of which, the 3DP and 3DPIM trays were preborder-moulded. The finished complete dentures were used to take impressions that were set as the reference group to analyse the accuracy of the final impressions. The impressions taken using the 3DP custom trays (preborder-moulded) were used as a reference to analyse the extensions of the impressions taken using the other three custom trays. Randomized block or Friedman tests were used to evaluate each group’s statistical significance. The results revealed that the 3DPIM custom trays with the inner marginal-band tissue stop facilitated the preborder-moulding process and improved the accuracy and extension of the impression.

Highlights

Accurate impressions provide the foundation for complete denture restoration and are closely related to the dentures’ retention and stability[1]
With good plasticity of the impression compound, the dentist must keep the tray in place and functionally move the soft tissue around the alveolar ridge to determine the impression margin’s correct location and morphology, thereby forming the border seal of the custom tray at the margin
The 3D-printed custom trays are shown in Fig. 4; the 3DP and 3DPIM trays were preborder-moulded with border-moulding wax, while the other two tray types were not

Summary

Introduction

Accurate impressions provide the foundation for complete denture restoration and are closely related to the dentures’ retention and stability[1]. Border moulding is important for obtaining an appropriate extension range and promoting complete denture retention[9,10] During this process, with good plasticity of the impression compound, the dentist must keep the tray in place and functionally move the soft tissue around the alveolar ridge to determine the impression margin’s correct location and morphology, thereby forming the border seal of the custom tray at the margin. They can only visually assess the border-moulding morphology to make adaptations, and even experienced dentists cannot always ensure the uniform thickness of the border-moulding material margins in a custom tray Tissue stop is another significant application that ensures precise custom tray placement[11,12,13]. Our group recently found that custom trays designed with saddle-shaped tissue stops can better control the impression material thickness but cannot promote formation of the impression’s margin morphology[14]. The results were evaluated using the impression surface precision and extension range

Methods

Results

Discussion

Conclusion