"Clinical Performance of an Incrementally Placed Highly Filled Composite, an Incrementally Placed Flowable Composite, and a Bulk Filled Composite in Class II Restorations"
Phase: NA
Conditions: Dental Caries
Sponsor: Solventum US LLC

 
Page 1 of 12 
 
“Clinical Performance of an Incrementally Placed Highly Filled 
Composite, an Incrementally Placed Flowable Composite, and a Bulk 
Filled Composite in Class II Restorations” 
 
 
                                          
 
 
 
Protocol February 12, 2020 (1/9/19 modification) 
 
NCT02889835 
 
 
 
 
 
UAB Principal Investigator: 
Dr Nathaniel Lawson 
UAB SOD 602 
1919 7th Ave South, Ste. 602 
Birmingham, AL   35233-2005 
Tel: 205-975-8302      Fax : 205-975-6108  
Email: jburgess@uab.edu 
 
 
 
Sponsor:  3M ESPE  
3M ESPE contact 
Rolf H. Halvorson PhD 
Clinical Research Manager 
3M ESPE Dental Products 
3M Center, Bldg. 260-2A-10 
Saint Paul, MN 55144-1000 
Phone: 651-733-3384 | Fax: 651-736-1678 
www.3MESPE.com 
 
rhhalvorson@mmm.com 

 
Page 2 of 12 
 
 
Sub-Investigators: 
Dr John O Burgess 
Dr Dan Givan 
Dr Chin-Chuan Fu 
Dr. Augusto A. Robles 
 

 
 
3
Introduction and Review of the Literature 
 
Flowable composites were first introduced to the dental profession in the 1990’s.1  The handling 
characteristics and syringe delivery system of flowable composites remove some of the challenges 
encountered with placing composite resin in small to medium size tooth preparations since the 
small tips allow the filling material to be syringed placed.  Early flowable composite resins were 
produced by reducing filler content or increasing the diluent monomers in the composite 
formulation to increase flow2.  A comparison of the filler content of these earlier flowable 
formulations were reported to be 20 to 25% less than that of the universal composite materials1. 
Unfortunately by reducing the reinforcing filler particles the mechanical properties of flowable 
composites are compromised1,2. 
 
Filler content influences the polymerization shrinkage of resin composites.  Since filler particles, 
unlike resin, do not contract during polymerization, increased filler content will decrease the 
polymerization shrinkage of composite resins.  In studies of experimental composites filled with 
varying concentrations of filler particles, filler concentration was inversely correlated to shrinkage 
and shrinkage stress.3,4  As flowable composite resin improved new resin monomers were 
produced further reducing shrinkage and shrinkage stress.3  Commercially available materials have 
demonstrated that composites with lower filler content have higher volumetric shrinkage5-7, 
shrinkage stress6,7 and shrinkage strain8 than more highly filled materials.  However volumetric 
shrinkage was not correlated to shrinkage stress for a series of commercially available flowable 
composites.7  This surprising data was explained by the reduced modulus of elasticity which allows 
flowable composites to compensate for shrinkage due to flow prior to polymerization.5 The clinical 
repercussion of polymerization shrinkage is tooth-composite marginal opening, possibly leading 
to leakage under a restoration.  In a vitro study Bonilla et al reported increased leakage under 
flowable composite occlusal restorations compared to highly-filled composites.9 
  
Early flowable composites, with reduced filler content, had less flexural strength than higher filled 
conventional composite filling materials raising concerns about increased bulk fracture of flowable 
composite resin restorations.  Using an experimental composite made by increasing hybrid filler 
content up to 65.2vol% and nanoparticle filler content up to 40wt% produced increased flexural 
strength.10,11  A comparative study of 72 commercially available composites showed that flowable 
resins with higher filler load (up to 60vol%) had increased flexural strength.12  However when the 
flexural strength between commercially available flowable composites and their universal 
counterparts were compared the flowable materials had higher flexural strength. Upon closer 
examination it was discovered that many of the flowable composites had higher filler 
concentration than the corresponding universal material.13,14   Two studies examining fracture 
properties determined that flowable materials showed similar fracture strength as highly-filled 
materials.15,16     
    
The wear resistance of flowable composites compared to universal composites is controversial. 
Older materials had lower wear resistance however there is a strong trend toward higher filler 
loading and increased wear resistance in currently marketed flowable materials.  Filler particles 
protect the weaker resin matrix during abrasive wear.17 Experimentally filled composites with 
micro-filers have shown increased wear at concentrations below 48vol% in one study while 
concentrations between 0-60wt% showed no difference in wear in another.18,19  Lim et al in an in 
vitro study reported increasing nano-filler concentration up to 35vol% improved wear resistance.20  

 
 
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In vitro wear studies of commercially available composites have generally shown more wear on 
flowable composites than highly-filled materials if the filler concentrations in both materials is 
similar.16,21  One study reported less wear on flowable composites, however, the flowable 
composites had higher filler concentration than the comparative universal composites.14 
 
A summary of laboratory data suggests that some flowable composites have greater 
polymerization shrinkage, increased wear and comparable flexural strength and fracture 
properties compared with universal composites.  Because some physical properties are lower than 
conventional composites, flowable composites have been used clinically for restorations with 
minimal occlusal loading, such as liners, small Class I and II cavities and Class V lesions.  A clinical 
trial of small Class I restorations restored with 2 flowable composites demonstrated that marginal 
discoloration and marginal adaption worsened 3 years after baseline.  However as these materials 
have developed their clinical performance has improved. Gallo et al have shown that the presence 
of secondary caries, anatomical form, retention, polishability, and color match of the flowable 
restorations did not significantly change over the three year period.22,23   A 2-year clinical trial 
compared conventional and flowable composites in Class II restorations and observed no 
difference between the materials.24  One 3-year and three 2-year clinical trials compared 
conventional and flowable composites in cervical lesions for marginal discoloration, marginal 
adaptation, secondary caries, surface texture, color match, and anatomic form.25-28  No difference 
was discovered between materials in any study except a clinical comparing restorations for non- 
carious cervical restorations.  One of these reported that the conventional material had superior 
marginal adaptation.25   
 
Traditionally composite resin restorations have been placed in 2 mm increments. These 
increments are added to fill the cavity due to the limited depth of cure that the restoring 
composite had. Recently a bulk placed flowable resin composite (Filtek Bulk Fill Flowable 
Restorative, 3M ESPE) has been developed and marketed with a curing system that will allow fewer 
increments to be placed to restore the cavity.  This composite resin has a 4mm depth of cure 
which allows fewer larger increments to be placed which shortens the tie needed to restore the 
tooth. Wear of the composite resin is an important property for the clinical success for dental 
composites especially for very large restorations with heavy occlusal contacts and is especially for 
patients with heavy or abnormal occlusal function. 2,3 
 
In vitro wear testing methods are used to measure wear and predict in vivo wear of composites. 
These methods are reliable and more cost effective than in vivo trials and allow quantitative 
measurement of wear.36,37  From data produced from in vitro wear resistance testing, the 3M Bulk 
Filled Flowable material has adequate wear resistance to be placed in a class II load bearing area.    
 
Table 1: In vitro wear of bulk placed composite resins 
 
Materials 
Type 
Volume/(mm3) 
Venus Bulk Fill-
Flowable/Heraeus Kulzer 
Flowable/nano-hybrid 
0.024±0.004A,F 
Filtek Bulk Fill/3M ESPE 
0.012±0.001B,C 

 
 
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Tetric Evo Ceram 
BulkFill/Ivoclar 
Nano-hybrid 
0.011±0.002C 
SureFil High Density Posterior 
Restorative (HDR)/Dentsply 
Packable 
0.007±0.001D 
SureFil SDR Flow/Dentsply 
Flowable 
0.04±0.01E 
Sonic Fill/Kerr 
Packable/nano-
hybrid/sonically activated 
delivery 
0.02±0.004F 
Quixx Posterior Restorative 
Packable 
0.02±0.006 
Z100/3M ESPE/(Control) 
Packable/microhybrid 
0.004±0.001G 
 
Studies in the past suggest that highly filled microhybrid composites may have greater wear 
resistance for contact-supporting posterior restorations than flowable microfilled resins. 39,40 
However current generation flowable composites have higher filler content and demonstrate 
higher wear resistance than early flowable resins and even some conventional bulk filled materials 
(Table 1).41-43 
 
Experimental Design and Methods:    
 
This clinical trial will compare three techniques using three materials (one for each technique) for 
restoring class II preparations.  The purpose of this clinical trial is to evaluate the effectiveness of 
a flowable resin composite (Filtek Supreme Ultra Flowable Restorative, filler content: 65 wt% and 
46 vol%) used in Class II restorations compared to a conventional highly filled composite resin 
(Filtek Supreme Ultra, filler content: 72.5 wt% and 55.6 vol%) and Filtek Bulk Fill in class II 
restorations.  This is a randomized prospective single-center, single-blinded, clinical trial 36 
months in duration.  We propose using one bonding agent (Scotchbond Universal, 3M ESPE) for 
this study with a total etch technique (the enamel and the dentin are etched).  Success with 
Scotchbond Universal, using the total etch technique was 100% in a 2 year44and 98% a three year45 
clinical study.   
 
Purpose: This study will examine the clinical success of 3 composite resins, a conventional 
composite (Filtek Supreme Ultra Universal Restorative, 3M ESPE) placed in 2 mm increments, a 
flowable composite resin (3M ESPE, Filtek Supreme Ultra Flowable, a flowable composite placed 
in 2mm increments) and a bulk placed and cured composite (Filtek Bulk Fill Flowable Restorative, 
3M ESPE). All composite resin restorations will be placed using a single adhesive Scotchbond 
Universal in a three year clinical trial.    
 
Objective: The objective of this study is to evaluate the clinical efficacy of these three 
restorative materials placed in class II posterior restorations using Scotchbond Universal 
adhesive.  To accomplish this goal we will place 50 class II composite resin restorations for 
each material and evaluate them in accordance with the ADA and FDI criteria.   

 
 
6
 
Specific Aims 
 
1. Place and 50 composite resins of each composite in Class II cavity preparations, evaluate the 
resin composite restorations used in the three techniques at baseline, 6 months, 1 year, 2 
years, and 3 years, using specific criteria (Attachment 2).  
2.  
 
 
Specific Aim: To place three commercially available resin composites in Class II cavity 
preparations, evaluate the resin composite restorations at baseline, 6 months, 1 year, 2  and 
3years using specific criteria (direct and indirect). 
 
Materials: 
Filtek Supreme Ultra Universal, 3M ESPE, placed and cured in 2 mm increments, Filtek Supreme 
Ultra Flowable a flowable composite resin placed and cured in 2 mm increments, and Filtek Bulk 
Fill Flowable a composite placed and cured in 4 mm increments will be used in this study.  All 
restorations will be placed with an adhesive, Scotchbond Universal, using a total etch technique.  
All composites and the adhesive used in this study are in use in the US dental market at this time 
and are commercially available (3M ESPE website). 
 
Duration of the Investigation: 
 
 
36 months 
 
Number of Restorations: 
At least 40 restorations are needed at 36-month recall.  Our experience at the UAB – School 
of Dentistry Clinical Research area with dropouts over a 36-month period is about 10%.  Fifty 
restorations will be placed to ensure ample restorations at the 36-month recall. 
 
Class of Restorations: 
Restorations will be placed in separate preparations in Class II in upper and lower jaw molars.   
All teeth will have natural teeth or crown and bridgework as antagonists. For the clinical 
evaluation of the resin, specific criteria (Attachment 2). will be used to evaluate, directly and 
indirectly.   
 
Distribution of Restorations: 
Sets of three restorations, one of each composite will be placed per patient for evaluation.  If 
needed by the subject two sets of class restorations may be placed.  
  
Patient Population: 
Patients for this investigation will be selected from patients of the Dental School at the 
University of Alabama at Birmingham (UAB) and from those recruited from advertisements 
placed in newspaper ads.   Approximately 50 subjects ranging in age from 19 to 90 years will 
be recruited for this study. The estimated subject number depends upon the number of 
restorations placed per subject.  Pregnant women will not be included in this study. 
 

 
 
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Inclusion Criteria: 
• 
must have given written informed consent to participate in the trial 
• 
must need at least three posterior dental fillings  
• 
replacement restorations due to caries or an esthetic replacement with or 
without caries are acceptable.  
• 
must be available for the required post-operative follow-up visits 
• 
restorations must be in contact with opposing natural or crowned teeth with at 
least at least one occlusal contact in habitual closure 
• 
Class II restorations must have at least one proximal contact 
• 
all restorations must Class II with a proximal contact with a natural or artificial 
tooth 
 
Subjects may be excluded from this study if they: 
• 
have severe medical complications (organ transplants, long term antibiotic or 
steroid treatment, cancer or immunocompromised) and disabilities who may 
not be able to tolerate the time required to complete the restorations or to 
provide adequate oral hygiene  
• 
have xerostomia either by taking medications known to produce xerostomia or 
those with radiation induced or Sjogren's syndrome patients   
• 
have chronic periodontitis, rampant caries or poor oral hygiene which may 
require extraction of the teeth to be restored   
• 
are unavailable for long term recall  
• 
cannot tolerate the rubber dam required for isolation of the tooth during 
preparation and restoration. 
• 
do not meet all inclusion criteria 
• 
present with any systemic or local disorders that contra-indicate the           dental 
procedures included in this study 
• 
have an unstable occlusion  
• 
have severe bruxing or clenching or in need of TMJ related therapy 
• 
have teeth with periapical pathology or expected pulp exposures 
• 
have teeth that are non-vital or that exhibit signs of pulpal pathology 
• 
are pregnant. 
 
Screening: 
Each subject will be screened for compliance with the inclusion/exclusion criteria 
specified above. After the risks and benefits are explained to the subject, they will 
be asked if they understand and any questions they have will be answered.  They 
will then be asked to give written informed consent and provided a copy of the 
consent form.  
 
Risks to the Patient:  
Patients will wear lead aprons as a protective measure during the radiographic procedure to 
minimize risk.  Patient data will be monitored and if, during the course of the study, it becomes 
apparent that the restorative material is significantly poorer than other currently marketed 
materials, the patient will be informed and if needed the restorations replaced. 
 

 
 
8
Consent: 
Consent for this study will be obtained prior to the initial examination and the initiation of any 
portion of the study.  The PI or Co-investigator will explain the consent to the patient and answer 
questions they may have.  The consent forms and all records associated with this study will be 
maintained in the clinical research office (Room 611) in the Clinical Research Clinic (three locked 
doors to enter) to ensure the records are confidential.  Each subject will provide written consent 
to participate in this study in accordance with Federal regulations (21 CFR Parts 50 and 56). 
 
 

 
 
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Materials 
 
Composite resins 
Shades 
% Filler 
Filler type 
Filtek Supreme 
Ultra Flowable 
 
65 weight % and 46 
volume % 
0.1 to 5.0 microns ytterbium 
trifluoride, a non-
agglomerated/non-aggregated 
surface modified 20 nm silica 
filler, on-agglomerated/non-
aggregated surface modified 75 
nm silica filler, and a surface 
modified aggregated 
zirconia/silica cluster filler 
(comprised of 20 nm silica and 4 
to 
11 nm zirconia particles). The 
aggregate has an average 
cluster size of 0.6 to 10 microns. 
Filtek Supreme 
Ultra Universal 
Restorative 
 
78.5% weight and  63.3 
% by volume 
a non-agglomerated/non-
aggregated surface modified 20 
nm silica filler, on-
agglomerated/non-aggregated 
surface modified 75 nm silica 
filler, and a surface 
modified aggregated 
zirconia/silica cluster filler 
(comprised of 20 nm silica and 4 
to 
11 nm zirconia particles). The 
aggregate has an average 
cluster size of 0.6 to 10 microns. 
Filtek Bulk Fill 
Flowable 
Restorative 
 
 
A1, A2, A3. B1 
and C2 shades. 
 64.5 % weight or 42.5 % 
volume % 
20 nm silica and 4-11 nm  
zirconia, aggregated 
zirconia/silica clusters and 
100nm ytterbium trifluoride filler 

 
 
10
Materials and Methods:  
 
Digital images will be made to document the restoration size and placement at each step.  Teeth 
will be cleaned with pumice and water to remove surface stains, a shade selected and the teeth 
to be restored will be isolated with a rubber dam. Filtek  Supreme Ultra and Filtek Supreme Ultra 
Flowable, will be placed inserted in 2 mm increments and lighted cure using a LED curing light 
with output of 1000-2000mW/cm2 which will be monitored to ensure irradiance greater than 
1000mW/cm2 throughout the trial.   Filtek Supreme Ultra will also be placed and cured in 2mm 
increments body, enamel will be cured for 10 seconds while dentin, A6B and B 5B will be cured 
for 20 seconds. These will be compared with each other and to Filtek Bulk Fill placed in 4 
increments and cured for 10 seconds.  All restored teeth will be in occlusion and at least one 
proximal surface of each class II restorations will be in proximal contact with an adjacent tooth.  
Cavity preparations will be prepared for all restorations following rubber dam isolation unless it is 
not possible due to abnormal anatomic considerations.  
 
 
Cavity Preparation Design 
 
Each proximal surface to be prepared will be pre-wedged with wooden wedges. Restorations must 
have a buccal to lingual width no greater than 1/3 the distance from buccal to lingual/palatal cusp 
tips.   All prepared margins will be placed ninety degrees to the external tooth surface.  Any tooth 
with a pulpal exposure will be excluded from the study. Any cavity preparations judged to be 
within 1mm of pulpal tissue either clinically or radiographically may be lined with Vitrebond (3M 
ESPE)  a glass ionomer liner.  A light cured, universal bonding agent Scotchbond Universal (3M 
ESPE, St Paul, MN) will be used for the restorations. Each composite will be placed per 
manufacturer directions. Composi-Tight (Garrison Dental) or Trident sectional matrices will be 
used with class 2 restorations.  However at the choice of the operator a Tofflemire circumferential 
matrix may be used. The composite will be photoinitiated with a light with an output of at least 
1000 mW/cm2. The two resin composites (Flowable and Filtek Supreme Ultra will be placed using 
an incremental fill technique, beginning with a 2 mm initial increment in the gingival floor, and 
completing the restoration with 2 mm increments.  The bulk fill will be placed and cured in 4 mm 
increments. Four clinicians will insert fifty restorations.  Carbide finishing burs will be used to 
remove gross excess, followed by finishing strips and disks (Sof-Lex, 3M, St Paul, MN), and the Sof 
Lex Diamond Polishing System.  All polishing will be done at slow speed with water spray.  After 
removing the rubber dam, adjusting the occlusion and polishing the restoration a digital image 
with the articulating paper marks on the tooth will be made. An conventional impression of the 
restoration will be taken with PVS impression material (Imprint 4) in a full arch or quadrant tray.  
 
Each restoration will be evaluated directly and indirectly at baseline (one week after restoration 
placement), at 6 months, 1, 2 and 3 years.  The direct clinical evaluations will be made using a 
modification of the USPHS and FDI guidelines. Each restoration will be evaluated for proximal 
contact, marginal discoloration, secondary caries, loss of anatomical form, and marginal 
adaptation, surface condition and post operative sensitivity.  Digital images will be used to 
document marginal staining and color match of the composite restoration to the tooth. A visual 
analog scale will be used to evaluate the sensitivity of the restoration by placing a cotton pellet 
soaked with skin refrigerant for three seconds.  The subject will mark their response on a calibrated 

 
 
11
line (10mm) where 1 represents no pain and 10 represents the worse pain possible like major 
surgery, childbirth etc.  
 
Evaluators will be trained and calibrated.  Preclinical sessions will train clinicians by preparing and 
restoring at least two extracted teeth mounted in stone.  A clinical training session will train 
clinicians to conduct the evaluations during sessions using patients with similar restorations 
placed in a previous clinical trial.  Scores for each evaluator will be compared to other evaluators 
and inter-evaluator comparisons made. The trained evaluators will independently evaluate each 
restoration in our clinical study and a forced consensus obtained if necessary. Those who evaluate 
the restorations must not evaluate the restorations they placed. Additional training will also be 
obtained by the e-calib tool. 
 
 
Data Analysis:  
The categorized clinical assessment data (color, marginal discoloration, secondary caries, 
anatomic form, marginal adaptation) will be summarized by computing percentages for each 
category and used to describe trends noted in the performance of the groups. In the analysis of 
categorical data of staining, marginal integrity, proximal contact, recurrent caries, retention, 
anatomical form and marginal adaptation, the frequency distribution over various categories will 
be calculated and reported.  A sample size of 50 restorations is not based on a statistical plan, but 
rather on guidelines put forth by the American Dental Association for obtaining approval as an 
amalgam replacement for posterior restorations.  The guidelines specifically call for an evaluation 
of a minimum of 40 restorations in a minimum of 20 subjects at 18 months. The basis for sample 
size is based by taking subject attrition into account over the 36 month clinical evaluation. All 
enrolled subjects, defined as those who have at least one experimental composite resin 
restoration - will be evaluated for safety of the composite.   
 
Restoration survival at thirty-six months will be assessed using Kaplan-Meier survival analysis and 
Log Rank (Mantel-Cox) test for equality. The three groups will compared with Kruskal-Wallis H 
test (mean rank scores, chi-square values, degrees of freedom, and p-values) for each FDI criteria 
at the thirty-six month recall using SPSS software (Microsoft).  
 
 
Criteria for evaluation: 
Modified USPHA and FDI criteria will be used to assess individual restorations.  Silicone 
impressions will be made at each recall to measure the marginal integrity and loss of anatomical 
form of each restoration.  
 

 
 
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SUMMARY  
 
Subjects that are from 19-90 years old will be eligible for this study.  Patients with health 
problems, who cannot tolerate the dental appointment, will be excluded.  Signs advertising the 
study will be posted in the dental school and in the local newspaper.  Up to 2 sets of three dental 
fillings for each patient will be filled with these materials in moderate sized cavities.  The patient’s 
teeth will be restored by using a local anesthetic and a rubber sheet (rubber dam) placed over the 
prepared teeth to isolate the cavities from the patient’s saliva.  The cavities will be prepared using 
currently accepted procedures, an impression or digital scan made of the preparation and the 
resin composite filling material will be placed after applying an etchant and adhesive to the cavity.  
The filling materials will be placed in increments according to the instructions for use. To ensure 
that the material is set or hardened sufficiently, the curing light (Elipar Deep Cure S, 3M ESPE) that 
activates the polymerization reactions of the filling material.  The light will be routinely checked 
to verify it meets the curing specifications noted in the composite instructions for use.   The biting 
surface of the restoration will be adjusted so that the patient’s teeth function the same as before 
the procedure. The restoration will be polished and an impression and digital scan of the 
completed filling will be made to record the filling at that point with and without occlusal biting 
markings.  A trained dentist will examine the patient’s fillings at 1 week, 6 months, 1, 2, and 3 years 
after placement of the filling.  At each recall appointment,  discoloration and decay at the margin 
of the restoration, wear of the biting surface, presence of defects such as gaps at the margin, 
amount of contact between adjacent teeth, and color matching with natural teeth will be recorded 
as scores according to an accepted clinical rating system.  For each category in the evaluation, 
percentages of alpha (perfect) scores will be tabulated.  Video images of the procedure to 
document the filling placement for at least one patient will be made