Clinical evaluation of closed tray impression and intraoral scanning techniques in single posterior tissue-level implant-supported crowns: A self-controlled case study

Zhi Chen; Yong Wang; Zhe Sun; Jing Zhao; Nengjie Lin; Yuanna Zheng

doi:10.1016/j.prosdent.2024.05.026

Clinical evaluation of closed tray impression and intraoral scanning techniques in single posterior tissue-level implant-supported crowns: A self-controlled case study

J Prosthet Dent. 2024 Jul 1:S0022-3913(24)00379-2. doi: 10.1016/j.prosdent.2024.05.026. Online ahead of print.

Authors

Zhi Chen¹, Yong Wang², Zhe Sun³, Jing Zhao⁴, Nengjie Lin³, Yuanna Zheng⁵

Affiliations

¹ Graduate student, Graduate Prosthodontics, School/Hospital of Stomatology, Zhejiang Chinese Medical University, Hangzhou, Ningbo Dental Hospital/Ningbo Oral Health Research Institute, Ningbo, PR China.
² Attending, School/Hospital of Stomatology, Zhejiang Chinese Medical University, Hangzhou, Department of Stomatology, Shangcheng District Jiubao Community Health Center of Hangzhou City, Hangzhou, PR China.
³ Resident, Department of General Dentistry, School/Hospital of Stomatology, Zhejiang Chinese Medical University, Hangzhou, PR China.
⁴ Attending, Department of General Dentistry, Hospital of Stomatology, Zhejiang Chinese Medical University, Hangzhou, PR China.
⁵ Professor, School/Hospital of Stomatology, Zhejiang Chinese Medical University, Hangzhou, Ningbo Dental Hospital/Ningbo Oral Health Research Institute, Ningbo, PR China. Electronic address: [email protected].

PMID: 38955602
DOI: 10.1016/j.prosdent.2024.05.026

Abstract

Statement of problem: Different techniques have been used to record the locations of dental implants, yet research examining the clinical outcomes of posterior implant-supported prostheses generated by different techniques, particularly concerning their fit, is lacking.

Purpose: The purpose of this self-controlled study was to evaluate the clinical outcomes of closed tray impression making and intraoral scanning for single posterior implant-supported restorations.

Material and methods: Eighty-two participants with a single missing posterior tooth were included. The restorations were delivered a minimum of 3 months after tissue-level implant placement. Each participant was provided with 2 screw-retained monolithic zirconia crowns, produced using 3-dimensional (3D) gel deposition from both closed tray impression making (control group) and intraoral scanning using an iTero scanner (experimental group). The recording operating time, the patient comfort assessed using a visual analog scale (VAS), and the fit of the crowns were recorded during clinical evaluation. The paired t test and Mann-Whitney U test were conducted to statistically analyze the differences between the 2 techniques (α=.05).

Results: Seventy-six participants completed the study with a dropout rate of 7.3%. The mean ±standard deviation recording operating time of the control and experimental groups was 683 ±164 and 777 ±407 s, respectively (P<.05). The mean ±standard deviation VAS score of the control and experimental groups was 2.6 ±1.6 and 1.3 ±1.0, respectively (P<.05). The crowns in both groups showed excellent marginal fit (P>.05), but the occlusal contacts of crowns in the experimental group were significantly better (P<.05), while the interproximal contacts were significantly worse (P<.05) compared with those in the control group. In the control group, 1 crown was rated as Delta for occlusal contact and deemed clinically unacceptable.

Conclusions: In single posterior tissue-level implant-supported restorations, the clinical outcomes of most of the screw-retained monolithic zirconia crowns generated from closed tray impression making and intraoral scanning with the iTero system and fabricated by 3D gel deposition were acceptable. Compared with the closed tray impression technique, intraoral scanning resulted in better patient comfort and occlusal contacts but worse interproximal contacts. Efficiency was lower with intraoral scanning.