Accuracy Evaluation of Implant Impressions: A Prospective Study

April 26, 2024 updated by: Ahmed Aziz, University of Sharjah

Accuracy Evaluation of Full-arch Implant Impressions Using Different Workflows: A Prospective Study

The aims of this clinical study are: 1) to compare the accuracy of conventional versus digital impression techniques for implant impressions; 2) to assess the passive fit of the prosthesis constructed from the most accurate impression.

Thirty edentulous patients who received 4 - 6 implant and indicated for implant-supported fixed prosthesis will be invited. Full-arch conventional and digital impressions will be made for each patient. Accuracy evaluation will be made and the prosthesis will be constructed from the most accurate impression. Passive fit of the zirconia implant-supported prostheses will be verified at the try-in stage clinically and radiographically.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The aims of this clinical study are: 1) to compare the accuracy of conventional versus digital impression techniques for implant impressions; 2) to assess the passive fit of the prosthesis constructed from the most accurate impression.

Study design The ethical approval will be obtained from the research ethics board. Thirty edentulous patients who received 4 - 6 implant and indicated for implant-supported fixed prosthesis will be invited. All participants will require to read and sign the informed consent form before initiation of the treatment. The impression procedures will be performed by one experienced prosthodontist. The prostheses will be evaluated by an independent prosthodontist.

Sample size calculation The sample size is calculated based on the tests for paired means. With α= 0.05, β= 0.2, mean of distance deviation, IOS= 17 μm, and standard deviation= 34 μm, a sample size of 25 is necessary, which would have the power of 90% to detect the difference. Therefore, a total of 25 patients will be invited to participate in this clinical study. This sample size is more than previous studies evaluating IOS and SPG workflows (15 - 17 patients). However, it has been reported that the dropout rate in clinical studies is 20%. For this reason, a total of 30 patients will be invited to compensate for the anticipated loss of patients.

Treatment procedure Conventional impression Abutment-level impression copings will hand tightened onto the abutments and splinted with autopolymerizing acrylic resin (Pattern Resin; GC), and allowed to polymerize. A custom open-tray splinted impressions will be made with a polyether material (Impregum Penta Soft; 3M ESPE). After 5 minutes, the impression copings will be unscrewed from the implants, and the impression will be removed. Type IV dental stone (dentostone 220; dentona AG) will be poured into the impression to generate a definitive cast. The models will be digitalized with a high-resolution laboratory scanner (E4; 3Shape A/S) with an accuracy of 4 mm to obtain the 3D data of the models in standard tessellation language (STL) format.

Digital impressions After tightening the scan bodies (CARES® RC Mono Scan body, Straumann, Basel, Switzerland), the intraoral scanner will be used according to the manufacturer's recommendations. Three scanners will be used since they have different ways of obtaining 3D images and working principles. The technology of Trios scanner (TRIOS 4, 3Shape A/S) depends on confocal microscopy, ultrafast optical scanning and auto-correction; Cerec Primescan (Dentsply Sirona) depends on optical triangulation and confocal microscopy; Medit i700 (Medit, Seoul, Korea) depends on 3D in-motion video technology, 3D full-color streaming capture and advance algorithm to stitch images. The scanning path will begin with the occlusal surfaces, then turned to the palatal or lingual surfaces, and lastly to the buccal surfaces of the scan bodies. Then, removing the scan body with a trim tool from the occlusal view and exporting the STL file.

Accuracy measurement All STL files generated from the intraoral scan (STL digital) and the STL files generated from cast digitization (STL conventional) will be imported into 3D inspection software (Geomagic, 3D Systems Inc., Rock Hill, SC) for merging and evaluation of 3D deviations. Following software best-fit alignment, the 3D comparison will be used to evaluate the 3D deviations between the digital files (STL files from IOS and digitized conventional working casts) limited to the area of scan bodies. Assessment of the root man square (RMS) deviations will be the primary outcome. The effect of the type of edentulous jaw (maxilla vs mandible) on the 3D deviations will be the secondary outcome, assessing whether the jaw has an effect on the amount of 3D deviations.

Prostheses fabrication The final restorative phase included definitive with one-piece, screw-retained zirconia implant-supported prostheses. The prosthesis will be constructed from the most accurate workflow after confirmation of the passive fit at the try-in appointment. In addition, the fit of the zirconia implant-supported prostheses will be confirmed prior to delivery, clinically and radiographically.

Statistical analysis Statistical analysis will be performed by SPSS version 29 (IBM Corp, Armonk, NY). Data will be presented as mean, median, and standard deviation. The normality of data will be tested by the Shapiro-Wilk test. The generalized linear mixed model will be used to compare the influence of scan bodies and impression copings on the accuracy of digital and conventional impressions. The fixed factors will be the 'IOS', 'type of scan body', 'type of impression coping' and their interaction. The precision will be calculated using the gamma distribution with the log-link function. The p values will be adjusted by the Bonferroni method for pairwise comparison (>.05).

All clinical outcomes will be assessed by one examiner. Since some patients will received more than one implant, linear mixed effect models (LMM) will be fitted using restricted maximum likelihood estimations to assess the effect of the follow-up time on repeated measurements of marginal bone loss, plaque index, calculus index, gingival index, bleeding index, and probing depth while accounting for within-person variability. LMM calculates means with standard errors as it estimates variability across multiple samples of a population (i.e., the different patients, implants, and repeated measures). The multivariable models included the fixed effects of the baseline value and follow-up in months. The interaction between the baseline and follow-up value (baseline value*follow-up) will be tested for model improvement. The included random effect will be the patient (i.e., random intercepts). The random effect of the follow-up (i.e., random slopes) will be also tested. Statistical comparisons will be performed using the type III analysis of variance test with Satterthwaite's method to estimate the degrees of freedom. A significance level of p< 0.05 will be chosen for all the analyses.

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

Edentulous patients who received implant surgery and indicated for implant-supported fixed prosthesis.

Patients rehabilitated with fixed full-arch interim prostheses with 4 - 6 implants

Exclusion Criteria:

Patients with severe systemic diseases, dementia, or muscle tremors will be excluded from the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Accuracy of full-arch implant impressions
Conventional and digital impressions will be made for each patient to compare the accuracy.
Procedure: Accuracy of full-arch implant impressions
Conventional impressions for full-arch implant impressions will be digitized and used as a reference for comparison.
Procedure: Accuracy of full-arch implant impressions using intraoral scanners
Digital scanners impressions for full-arch implant impressions will be compared to the reference (conventional) impressions

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Accuracy of conventional versus digital impression techniques for implant impressions
Time Frame: 6 months
Following the best-fit algorithm, the accuracy will be measured in terms of 3D comparison to evaluate the 3D deviations between the digital files (STL files from IOS and digitized conventional working casts) limited to the area of scan bodies.
6 months
The passive fit of the prosthesis constructed from the most accurate impression
Time Frame: 6 months
Clinical assessment of the prosthesis at the try-in stage using one screw test.
6 months
The passive fit of the prosthesis
Time Frame: 6 months
Radiographic assessment of the prosthesis by periapical radiograph
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Sharjah

Investigators

  • Principal Investigator: Ahmed Aziz, PhD, University of Sharjah

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

May 1, 2024

Primary Completion (Estimated)

August 2, 2024

Study Completion (Estimated)

September 1, 2024

Study Registration Dates

First Submitted

April 23, 2024

First Submitted That Met QC Criteria

April 26, 2024

First Posted (Actual)

May 1, 2024

Study Record Updates

Last Update Posted (Actual)

May 1, 2024

Last Update Submitted That Met QC Criteria

April 26, 2024

Last Verified

April 1, 2024

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • REC-23-05-12-02

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Data will be shared upon reasonable request

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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