Clinical Evaluation of Lithium Disilicate CAD/CAM Crowns
Phase: NA
Conditions: Caries, Dental Trauma
Sponsor: Ivoclar Vivadent AG

Clinical Evaluation of 
Lithium Disilicate Quartz 
Chairside CAD/CAM Crowns 
University of Michigan IRB: HUM00191892 
Dennis J. Fasbinder, DDS 
27Jul2021 
Date 
Copyright University of Michigan 2020: This Clinical lnvestigation Proposal, or any part thereof, may neither be 
passed on to third parties nor may it be reproduced, stored in a retrieval system, or transmitted, in any form or by 
any means; electronic, mechanical, photocopying, recording, or otherwise, without prior permission of Dr. Dennis 
J. Fasbinder, University of Michigan, USA.

Clinical Evaluation of Lithium Disilicate Quartz Chairside CAD/CAM Crowns 
 27-Jul-21
PI: Dr. DJ Fasbinder 
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1 Investigation Title 
Clinical Evaluation of Lithium Disilicate Quartz Chairside CAD/CAM Crowns 
2 Investigator 
Dennis J. Fasbinder, DDS 
Clinical Professor 
Department of Cariology, Restorative Sciences, and Endodontics 
School of Dentistry 
University of Michigan 
1011 N. University 
Ann Arbor, Michigan  48109-1078  U.S.A. 
Phone: 
 
Fax: 
 
e-mail: 
3 Sponsor 
Ivoclar Vivadent, Inc 
Contact: 
Dr. Thomas Hill 
Ivoclar Vivadent, Inc. 
Manager - Scientific Services 
175 Pineview Drive, Amherst, New York 14228-2231 
4 Background 
 
There has been significant interest in computer assisted design/computer assisted 
machining (CAD/CAM)-generated restorations as the technology has evolved.  Of particular 
recent interest are newer high strength materials that have been introduced for chairside 
applications.  Lithium disilicate CAD/CAM restorations have been popular due to an esthetic 
result with high strength.  However, a somewhat involved and lengthy fabrication process after 
the restoration has been milled, including crystallization oven firing under vacuum is required 
to achieve the desired results.  Full contour zirconia crowns have increased in clinical 
application for a number of reasons including a more conservative preparation, improved 
fracture resistance of the material, and ease in cementation.  However, an oven fired sintering 
process using the SpeedFire oven (Dentsply Sirona) is required to generate the high strength of 
the zirconia.  And the time required for sintering is similar in length to the lithium disilicate 
crystallization process.  Initial full contour zirconia materials available for chairside CAD/CAM 

Clinical Evaluation of Lithium Disilicate Quartz Chairside CAD/CAM Crowns 
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PI: Dr. DJ Fasbinder 
 
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crowns had high strength (>900 MPa flexural strength), but also were relatively opaque 
compromising the esthetic results. 
 
 
An innovative high strength, lithium disilicate ceramic material is reported to offer a 
more efficient fabrication process resulting in a similar esthetic and high strength crown.  
Lithium Disilicate Quartz (Ivoclar Vivadent) is a glass ceramic with crystalline phases of lithium 
disilicate and quartz.  
 
 
Current glass ceramic materials have a recommended minimum thickness to maintain 
the maximum strength potential of the material.  An occlusal thickness of 1.5 mm is generally 
recommended.  This can be a challenge to achieve in the posterior of the mouth with teeth 
with limited clinical crown height.  In addition, the glass ceramic material should be adhesively 
bonded to ensure maximum strength of the restoration.  Lithium Disilicate Quartz offers an 
alternative high strength ceramic that may allow a more conservative occlusal reduction 
resulting in a crown thickness of 1.2 mm, equitable to the recommendation for full contour 
zirconia crowns.  The material may also be sufficiently strong to allow for conventional 
cementation in addition to adhesive bonding.   
Current high strength materials have not been embraced for partial coverage 
restorations due to the lengthy post-milling firing process.  Lithium Disilicate Quartz may also 
offer a more clinical efficient process to fabricate partial coverage restorations since it does not 
require post-milling crystallization. 
 
 
It is the intent of this investigation to evaluate the clinical application and performance 
of the new high strength, lithium disilicate quartz material for CAD/CAM-generated chair-side 
crown applications. 
 
5 Summary of Objectives and Design 
 
 
This investigation will be a randomized, prospective, longitudinal clinical trial to study 
the clinical performance of a new monolithic, high strength precrystallized lithium disilicate 
material for chairside CAD/CAM crowns.  The restorations will be evaluated for a period of five 
years. 
 
6 Specific Aims 
The specific aims of this project are: 
1. Evaluate the short-term post-operative sensitivity associated with cementation 
techniques using a self-adhesive, self-curing resin cement and a total etch/universal 
bonding agent with a dual-cured resin cement. 
2. Evaluate the resistance to material chipping and fracture of reduced thickness high 
strength precrystallized lithium disilicate CAD/CAM crowns. 

Clinical Evaluation of Lithium Disilicate Quartz Chairside CAD/CAM Crowns 
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PI: Dr. DJ Fasbinder 
 
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3. Evaluate the longitudinal clinical performance of precrystallized lithium disilicate crowns 
over five years of clinical service.  The crowns will be evaluated with modified FDI 
criteria for maintaining their esthetic, functional and biological properties. 
 
7 Research Plan: Methods and Materials 
 
7.1 Subjects 
 
 
The patient population will be selected from current patients under clinical treatment at 
the University of Michigan Dental Clinics.  Patients will be at least 18 years of age, of either 
gender, and of any ethnic background.  Each patient should have at least one carious lesion or 
defective restoration to be restored on a maxillary or mandibular premolar or molar tooth. 
Each lesion or defective restoration should exhibit sufficient size or loss of tooth structure 
requiring a full crown restoration.  The tooth should have at least one opposing tooth in 
occlusion and one adjacent tooth with an intact proximal contact.  All teeth will test vital and be 
asymptomatic at the beginning of treatment.  No more than two restorations will be placed per 
patient.  If a patient presents with more than two acceptable teeth for the study, molar teeth 
will be included prior to premolar teeth.  Exclusion criteria will include: 
 
Devital or sensitive teeth 
 
Teeth with prior endodontic treatment of any kind 
 
Teeth with a history of direct or indirect pulp capping procedures 
Patients with significant untreated dental disease to include periodontitis and/or rampant 
caries 
Women who self-report that they are possibly pregnant, pregnant, or lactating, as elective 
dental treatment is not indicated at these times 
Patients with a self-reported past history of allergies to the materials to be used in the study 
including composite resin cements or ceramic restorative materials 
 
Patients unable to return for the recall appointments 
 
 
7.2 Study Size 
 
 
There will be a maximum total of 80 monolithic, high strength precrystallized lithium 
disilicate crowns (Quartz by Ivoclar Vivadent).  There will be 2 groups of 40 crowns 
differentiated by occlusal thickness and type of cement.  
Group 1 = occlusal thickness of 1.5 mm delivered with a self-adhesive, self-curing resin 
cement (SpeedCem Plus/Ivoclar). 
Group 2 = occlusal thickness of 1.2 mm delivered with Adhese Universal Adhesive in 
total etch mode with a dual cure resin cement (Variolink Esthetic by Ivoclar 
Vivadent). 

Clinical Evaluation of Lithium Disilicate Quartz Chairside CAD/CAM Crowns 
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PI: Dr. DJ Fasbinder 
 
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The study will be a randomized, longitudinal clinical study with the outcome data to be 
benchmarked against published results of other chairside CAD/CAM materials. 
 
8 Data Collection 
 
8.1 Post-Operative Sensitivity 
 
 
To evaluate the immediate post-operative sensitivity, patients will be contacted by 
telephone once a week after the initial appointment for four weeks or until the restoration is 
reported asymptomatic.  A criterion-referenced rating scale will be used to measure sensitivity.  
The phone interview will be used as a follow-up procedure to minimize recall loss as the patient 
is not required to return to the clinic.  During the phone interview a criterion-referenced rating 
will be made of functional tooth sensitivity using the following scale.  Patients will only be asked 
to return for an evaluation if they are having continued discomfort or any indication of 
premature occlusal contact. 
 
Sensitivity Criteria: 
1=  No sensitivity is experienced at anytime 
2=  Slight sensitivity is experienced occasionally but it is not uncomfortable 
3=  Moderate sensitivity is experienced intermittently and it is noticeably uncomfortable 
4=  Severe discomfort is noted routinely with cold or pressure stimulation 
 
 
8.2 Clinical Evaluation 
 
 
Two independent evaluators will examine all crowns in the study.  Clinical evaluations 
will be made at baseline, six months, one year, two years, three years, four years, and five years 
using written criteria based on FDI criteria (Hickel et al., 2007 and 2010) (see Appendix for 
criteria description).  Disagreements in evaluations will be discussed between the evaluators 
and a consensus judgment will be reached and recorded for every criteria. 
 
 
Intraoral digital color pictures at a 1:1.5 magnification will be taken to document pre-
operative, cavity preparation, and post-operative conditions.  Facial and occlusal views of the 
tooth will be documented for both the pre-operative and post-operative conditions including 
occlusal contacts.   
 
 
A post-cementation quadrant optical scan (CEREC PrimeScan) will be made of each test 
restoration at each recall visit.  The scan will include the quadrant with the test crown, the 
opposing quadrant and buccal bite. 
 
 
Bite-wing radiographs (BWXR) of each test tooth will be reviewed at the three-year 
recall.  A new BWXR will be taken at the recall appointment at no cost to the patient if BWXR 
dated within 6 months of the three-year recall is not available for review.  The use of 

Clinical Evaluation of Lithium Disilicate Quartz Chairside CAD/CAM Crowns 
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PI: Dr. DJ Fasbinder 
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radiographs in the study is in compliance with the standard of care for ensuring and 
maintaining the health of the tooth during treatment and not for research-specific reasons. 
8.3  Data Management 
Case Report Form (CRF) 
 
Castor EDC is a cloud-based Electronic Data Capture (EDC) platform which will be used 
to collect data. All changes are tracked by an audit trail. The pictures are stored locally at the 
University of Michigan. After entering data by a study coordinator the data will be reviewed 
and approved by the principal investigator 
9 Statistical Analysis 
 
After the clinical evaluation data is collected for baseline and each recall, the clinical 
ratings will be entered into a statistical management program and appropriate non-parametric 
tests will be run to verify significant differences. Each criterion-referenced category will be 
analyzed independently.  At any given time period, significant differences in clinical evaluation 
ratings will be determined. 
10 Project Time Line 
 
The recruitment of patients and clinical placement of restorations will begin 
immediately upon approval and funding of the project.  It is anticipated to take 10 months to 
recruit and deliver the restorations required for the study.  The 1-year recall will occur in the 
second year of the study, and similarly for future recalls in that the 2-year recall will occur in the 
third year of the study and continuing.  This will result in a total time of 6 years required to 
place and complete the 5-year recall of the restorations with an additional 9 months needed to 
complete the data analysis and final report for the project.  Additional recall periods beyond the 
5 years may also take place following approval by Ivoclar Vivadent.