Basic Study of Fabricating Biomorphic Crowns

June 21, 2016 updated by: Ji-hua Chen, Air Force Military Medical University, China

Comparative Evaluation of Different Occlusal Surface Designs of Artificial Crown

The purpose of this study is to compare among different designs of the occlusal surface of artificial crowns, trying to determine a guidance of fabricating artificial crowns with better mimesis of the original tooth crown in terms of morphology.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

For occlusal surface design, each subject would be given 3 crowns using different fabricating guidance -- the FGP technique(FGP),the average setting technique(AVR) and conventional technique(CON), separately. Upon baseline visit, general tooth preparation procedures would be performed, including impression taking before and after treatment and tooth preparation. Sometimes photo taking is needed. On try-in visit, subjects would be ask to fill in questionaires(Likert's scale) and the adjusting time for each crown would be recorded. Moreover, t-scan would be used to assess the occlusal equilibrium. All in all, including adjusting visit for FGP, the subjects have to visit the clinic for 3 times which would take them 3-week time.

The Institutional Board(IRB) of the Stomatological Hospital of Fourth Military Medical University(FMMU) would be in supervision of the whole study and is responsible for the quality assurance plan, data check and source data verification.

Subject recruitment would done within those patients visit the department of prosthodontics of the Stomatological Hospital of FMMU and have an interest towards this study. One clinician would be appointed to enroll the subjects according to the standards. To avoid errors, all the examinations done in the study shall be accomplished by the same clinician and the crowns fabricated in the study shall be designed by the same technician. The clinician and the technician participated would receive adequate training before the study to ensure their performance. Every subject in the study should assign informed consents at the beginning of the study and establish case report forms(CRFs). During the study, if adverse events(such as crown chipping, crown dropping or iatrogenic gingivitis, etc) happen, subjects are required to contact the investigator within 24 hours; and the investigator should then report to the IRB within 24 hours. Following treatment or compensation would be done according to the clauses stated in the informed consent signed by the subjects.

The whole study needs subjects in total. During the study, subjects have their own right to quit the study at any time if they have discussed with the investigator in advance. These subjects then are deemed as "unavailable". If subjects don't contact the investigator and quit the study(the investigators can't contact them within the follow-up period), their records then are deemed as "missing".

All the information collected in the study would be protected and only be used within this study. The statistical analysis of this study would be processed with the aid of the department of statistics of FMMU.

Study Type

Interventional

Enrollment (Actual)

12

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

  • China
    • Shanxi
      • Xi'an, Shanxi, China, 710032
        • Stomatological Hospital of Fourth Military Medical University

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 to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • single crown restoration needed in posterior quadrants
  • the antagonist of the abutment tooth is purely natural or received minimum restorations that does not change its morphology too much
  • no orthodontic treatment history
  • stable occlusion
  • no parafunctional movements existed

Exclusion Criteria:

  • sequential crown restorations needed
  • the morphology of the antagonist of the abutment tooth has been largely changed by previous treatment
  • no contact exists between the abutment tooth and its antagonist
  • orthodontic treatment history
  • unstable occlusion
  • existed parafunctional movements
  • participated in other clinical studies

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: FGP design (FGP, AVR)
use functional generated path to execute different occlusal surface designs of the artificial crown and evaluate its efficacy
Procedure: FGP
To execute FGP technique, the occlusal surface of the interim should be back cut to leave at least 1mm occlusal space. Then apply the recording resin. Ask the subjects to close the mouth to maximum intercuspal position then perform right lateral, left lateral and protrusive movements in succession ending in maximum intercuspation position. Excessive resin then should be trimmed off and Bausch articulating paper would be used to mark the intercuspal contacts. Zinc oxide is then applied to check eccentric occlusion, trimmed off resin if there're interferences. Then the interim would be used as a copy to design the occlusal surface of the crown. (CAD/CAM)
Other Names:
  • general
Procedure: AVR
the crowns in this group would be designed by setting virtual articulator to average mode (CAD/CAM)
Other Names:
  • average value
No Intervention: conventional design (CON)
use conventional method to execute different occlusal surface designs of the artificial crown and evaluate its efficacy

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
△OT Value
Time Frame: 2 weeks(plus or minus 7 days) after tooth preparation

Occlusion time (OT) is defined as the time from the first contact of occluding teeth to maximum intercuspation. OT is directly related with patients' occlusal contact pattern; and some have considered it as a capable description of occlusion.

In the study, the OT value of each crown would be assessed before try-in (baseline) and immediately after try-in using T-scan (FGP, AVR, CON). Try-in procedure would be finished by the same clinician.

△OT was calculated for minimizing individual difference among participants. The equation for △OT was:△OT(FGP/ AVR/ CON)= OT (FGP/ AVR/ CON)-OT(baseline)
2 weeks(plus or minus 7 days) after tooth preparation
△DT Value
Time Frame: 2 weeks(plus or minus 7 days) after tooth preparation

Disocclusion time (DT) is defined as the time from maximum intercuspation to complete disocclusion during lateral movement. DT related tooth contacts with muscle activity. Abnormities in DT would result in change of muscle activity, thus facilitate the occurrence of temporomandibular joint disorders.

In the study, the DT value of each crown would be assessed before try-in (baseline) and immediately after try-in using T-scan (FGP, AVR, CON). Try-in procedure would be finished by the same clinician.

△DT was calculated for minimizing individual difference among participants. The equation for △DT was: △DT(FGP/ AVR/ CON)= DT (FGP/ AVR/ CON)-DT(baseline)
2 weeks(plus or minus 7 days) after tooth preparation

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Occlusal Adjusting Time for Crowns
Time Frame: 2 weeks(plus or minus 7 days) after tooth preparation
Try-in procedure would be finished by the same clinician. The occlusal adjusting time would be counted using a timer and recorded.
2 weeks(plus or minus 7 days) after tooth preparation
Likert's Scale
Time Frame: 2 weeks(plus or minus 7 days) after tooth preparation

The questionaire was designed to evaluate participants' feeling towards the occlusal interference. It would be given to the subject after immediately try-in the crowns. In the questionaire:

Score 0 = No interference (feel comfortable while biting on the artificial crown) Score 1 = Moderate interference(could feel the artificial crown is higher when biting on the artificial crown, but when firmly clenched, the upper teeth could bite on the lower ones) Score 2 = High interference(the artificial teeth is higher that the upper teeth couldn't bite on all the lower teeth when firmly clenched)
2 weeks(plus or minus 7 days) after tooth preparation

Collaborators and Investigators

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

Sponsor

Air Force Military Medical University, China

Investigators

  • Study Chair: Jihua Chen, PhD, Stomatological Hospital of FMMU

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

December 1, 2015

Primary Completion (Actual)

March 1, 2016

Study Completion (Actual)

March 1, 2016

Study Registration Dates

First Submitted

November 16, 2015

First Submitted That Met QC Criteria

November 18, 2015

First Posted (Estimate)

November 20, 2015

Study Record Updates

Last Update Posted (Estimate)

August 2, 2016

Last Update Submitted That Met QC Criteria

June 21, 2016

Last Verified

June 1, 2016

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • IRB-REV-2015039

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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