Longevity of Dental Fillings Utilizing 3D Printing

November 13, 2020 updated by: University of Oulu

Longevity of Dental Fillings by Chairside Technique Utilizing 3D Printing vs. Direct Composite Fillings

The aim of the present study is to compare the success of dental fillings prepared using 3D printing technique to those manufactured with the direct composite technique. A total of 100 adult patients will be selected from dental patients attending Kaarina Municipal Health Care Centre from October 2020. The inclusion criteria are as follows: presence of multiple cavities, fractures or cosmetic demands on bilateral permanent teeth. The restorative demand should be a class II, III or IV on first or second molars, or premolars. At least two fillings should be from the same tooth group (premolar/molar) in each patient. This will be a split-mouth study, whereby one tooth on one side will be restored using direct technique, and the contra lateral tooth restored using the indirect technique through random allocation. For both direct and indirect restorations, commercially available short-fibre reinforced composite material (Ever X Flow, GC) is used for core material (replacing dentin) and flowable composite material (Gaenial Universal Injectable, GC) for surface (replacing enamel, appr. 2mm thickness from the surface), according the manufacturer´s instructions. Clinical evaluations will be conducted immediately after the final finishing, and after 1 year, 3 years and 5 years. The evaluation will be based on the United States Public Health Service (USPHS) criteria. Descriptive statistics will be used to describe the frequency distributions of the evaluated criteria. To analyse the failure rate for direct vs. indirect restorations, 2x2 tables will be created. Non-parametric statistical procedures will be used due to ordinally structured data for the assessment of the restorations. Mann-Whitney U-test will be used to explore significant differences at different time points between direct and indirect restorations.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Detailed Description

Introduction

In dentistry, filling materials are needed repairing damage caused by dental caries as well as for occlusal rehabilitation. Composite restorations can be performed using direct or indirect technique. There are some shortcomings linked with direct technique, such as polymerization shrinkage, and also their manufacturing can be demanding due to circumstances in the oral cavity. Partly due to these, approximately 8 out 10 regular users of dental services need repetitive repair or replacement of old restorations within 5 years. One solution for manufacturing high-qualified and long-lasting restorations is chairside CAD/CAM (computer-aided design and computer-aided manufacturing) technology that includes both subtractive and additive manufacturing techniques. Additive techniques, also called 3D printing techniques, may provide novel possibilities to overcome the challenges linked with the durability of dental fillings. They might be used to fabricate more complex restorations compared to subtractive techniques with a reasonable cost. In 3D printing, successive layers of material are deposited under computer control to create an object layer by layer. The objects, having practically any shape or geometry, are produced from a model or design in an electronic form. The 3D printable models may be created with a CAD software package and in many cases utilize the imaging data by a dental scanner which have become widely available with high resolution. 3D printing may enable higher restoration accuracy compared to subtractive manufacturing techniques, where the accuracy is limited by the milling unit and machining tools. Another benefit is its low material loss. 3D printing process is fast and likely in future to be used chairside at the dental office. Only a few studies addressing the possibilities of 3D printing in dental filling manufacture exist in the current literature. Based on a previous in vitro study by the imvestigators, the accuracy of 3D printing technique is at least at the same level as milling technique in fabrication of dental inlay and onlay fillings, and thus might be a clinically acceptable alternative to the subtractive milling technique. Additional clinical investigations are needed to confirm these findings. The aim of the present study is to compare the success of dental fillings prepared using 3D printing technique to those manufactured with the direct composite technique.

Material and Methods

At total, 100 adult patients are selected from dental care patients of the Health Centre of Kaarina, Kaarina, Finland, as volunteers. Written informed consent forms are obtained from all patients at the beginning of the study. Participation in the study is voluntary and causes no additional costs for the patient.

Each patient requires two Class II, III or IV cavities to be restored in the dentition. The randomizations are performed by noting each tooth to be restored (Fédération Dentaire Internationale [FDI] two-digit code) on one form and the type of restorative system (direct technique vs. indirect technique utilizing 3D printing) on a second. First, a tooth number is drawn blindly. Subsequently, a restorative system is allocated to this tooth by blind drawing. The clinical procedures of cavity preparation and restoration placement are performed by two experienced dentists.

Clinical Evaluation Restorations are rated independently by blinded dentists at the Institute of Dentistry, University of Turku, Finland, who are not involved with the insertion of the indirect and the direct restorations and are unaware of the group status of the fillings. The two evaluators are calibrated against a reference standard. This clinical assessment method results in ordinally structured data for the outcome variables.

Statistical Analysis Power analysis was used to estimate the sample size. In the calculation, the distributions for clinically excellent or acceptable restorations (direct 87% vs. indirect 93%) based on a previous study. Based a previous in vitro study, it was estimated that restorations based on 3D printing technique have at least as high success rate as indirect ceramic restorations, 96%. When the statistical significance was set p <0.05, alpha coefficients 0.05 and beta value 0.2, the sample size n=150 tooth restorations per group was calculated. The number of patients for the study is estimated between 75 (when 4 restorations are performed for each patient) and 150 (2 restorations performed for each patient).

Descriptive statistics are used to describe the frequency distributions of the evaluated criteria. To analyse the failure rate (distributions of Charlie scored versus non-Charlie-scored restorations) for direct vs. indirect restorations, 2x2 tables are created. Non-parametric statistical procedures are used due to ordinally structured data for the assessment of the restorations. Mann-Whitney U-test is used to explore significant differences at different time points between direct and indirect restorations. The same test is used to detect differences between baseline and follow-up registration. The standard value considered to demonstrate statistically significant differences was set at p <0.05.

Ethical issues

Participation in the study is voluntary and requires an informed consent of the patient. The patient has a right to refuse or interrupt his/her participation in the study at any stage. The patients are treated according to the good clinical practices. Quality of the treatment is suspected to be at least at the same level as in normal treatment methods for restorative care. During the study, the patients will have additional check-ups as, which is compensated with economical or other benefits. Patient data are saved in patient registers at the care-providing instances. Research data are saved and analysed anonymously using SPSS 25 (IBM Statistic Viewer) program.

Study Type

Interventional

Enrollment (Anticipated)

100

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 Locations

  • Finland
      • Oulu, Finland, 90014
        • Research Unit of Oral Health Sciences, University of Oulu

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • presence of cavities, fractures or cosmetic demands
  • first or second molars and permanent premolars needing restorations
  • at least two class II restorations from the same tooth group (premolar/molar) should be performed in each patient
  • the number of restorations of each technique should be equal in each patient

Exclusion Criteria:

  • pulp exposure or risk of it during caries removal or cavities with imminent risk of pulp exposure
  • spontaneous pain or sensitivity to percussion

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: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Indirect restorations
For the indirect technique, the cavities are prepared according to the common principles for inlays/onlays. Digital impressions are taken of each tooth with a digital impression system (3Shape TRIOS® Intraoral Scanner).The dentist, utilizing the scanner's CAD SW, designs the 3D restoration. The design is imported from the scanner SW into the Rayo 3DToothFill SW to manufacture the mould and the restoration. After printing the mould, it is transferred to the Rayo robot which manufactures the restoration by casting filling material layers in the mould. The automated filling and curing procedures in the Rayo 3DToothFill robot are directed by Rayo 3DToothFill SW. After the manufacturing process is finished, the dentist cements the finished restoration into the cavity with a dual-cure resin cement (G-CEM LinkAce®).The indirect fillings are manufactured chair-side from the same composite material as in the direct technique.
Procedure: Indirect restorations
see the Arm description
Active Comparator: Direct restorations
The direct composite restorations are performed based on normal treatment practices. For both direct and indirect restorations, commercially available short-fibre reinforced composite material (everX Flow, GC) is used for core material (replacing dentin) and flowable composite material (G-ænial® Universal Injectable, GC) for surface (replacing enamel), according the manufacturer´s instructions. The occlusion and articulation are checked and adjusted, and the restoration is finished with polishing instruments.
Procedure: Indirect restorations
see the Arm description

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The United States Public Health Service (USPHS) criteria; changes during the follow-up period
Time Frame: baseline, and 1 year, 3 years and 5 years after baseline
The USPHS criteria include the following evaluations: retention, postoperative sensitivity, secondary caries, colour match, anatomical form, marginal discoloration, marginal adaptation, and surface texture. This clinical assessment method results in ordinally structured data for the outcome variables (A, Alpha = excellent result; B, Bravo = acceptable result; C, Charlie = unacceptable, replacement of the restoration necessary).
baseline, and 1 year, 3 years and 5 years after baseline

Collaborators and Investigators

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

Sponsor

University of Oulu

Collaborators

University of Turku
Oulu University Hospital
University of Helsinki
University of Eastern Finland

Investigators

  • Study Director: Kirsi Sipilä, Professor, University of Oulu, Finland

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 (Actual)

September 15, 2020

Primary Completion (Anticipated)

March 31, 2026

Study Completion (Anticipated)

December 31, 2026

Study Registration Dates

First Submitted

October 26, 2020

First Submitted That Met QC Criteria

November 13, 2020

First Posted (Actual)

November 16, 2020

Study Record Updates

Last Update Posted (Actual)

November 16, 2020

Last Update Submitted That Met QC Criteria

November 13, 2020

Last Verified

November 1, 2020

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2924410-5

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Study Data/Documents

  1. Study Protocol

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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