Primer Aligner Study
Phase: NA
Conditions: Malocclusion
Sponsor: Align Technology, Inc.

 
 
 
 
 
 
 
 
 
 
Primer Aligner Study  
NCT02550938 
July 7, 2015  
 

Study Summary  
Title 
Primary Aligner Study  
Objectives 
The primary objective was to determine the impact of primer aligners in both 
the 7 aligner set Invisalign treatment and the 12 aligner set Invisalign 
treatment. Results were measured by total treatment time (in days), and 
refinement rate per cohort. 
Purpose 
The purpose of this study was to demonstrate that allowing time for the 
biological response of the periodontal ligament (PDL) resulted in successful 
achievement of clinical outcomes and subject/doctor satisfaction. 
Relevant Scientific 
Background 
Align offers treatment options to treat minor tooth movements.  These 
products consist of a limited number of aligners in a treatment. One of the 
clinical barriers to adoption for treatments requiring a pre-set low number of 
aligners can be the lack of clinical outcomes and predictability in the set 
number of aligner sets.  A potential explanation for this hypothesis is that a 
biological delay, or “lag”, in tooth movement occurs at the beginning of 
treatment.  This lag is usually quantifiable and takes up to 3 aligner sets for 
the biological response to begin.  This biological delay may particularly impact 
low number aligner treatments. 
Design 
This was a non-significant risk, multicenter, randomized prospective study. A 
total of twenty-one (21) doctors participated in this study, 13 in the U.S. and 
eight (8) in the U.K.  There were 253 subjects enrolled into the study, 198 
from the U.S. and 55 from the U.K. All subjects received Invisalign® Full 
treatment per the standard Invisalign® Instructions for Use.  
Subjects were randomly placed into one of four different cohorts:  
• 
Cohort 1: 7 aligner Cohort wear time 1 
• 
Cohort 2: 7 aligner cohort wear time 2 
• 
Cohort 3: 12 aligner cohort wear time 1 
• 
Cohort 4: 12 aligner cohort wear time 2 
Primary Outcomes 
Total treatment time (in days) and refinement rate (%) was compared 
between the 7 aligner and 12 aligner cohorts.  
• 
Subjects were followed for the duration of orthodontic treatment, an 
average of 37 weeks/262 days.  
Treatment 
The Invisalign® System.  

Eligibility Criteria 
Inclusion Criteria: 
A subject were considered eligible if all of following inclusion criteria were 
fulfilled: 
• 
Subject must have fully erupted dentition  
• 
Age range ≥18 years old (Adult subject) 
• 
Subjects who are indicated for either: 5, 7, 10, or 12 aligner sets 
Exclusion Criteria: 
A subject was considered ineligible if any one of the following exclusion 
criteria were fulfilled: 
• 
Subject who has unerupted, erupting, partially erupted dentition 
(except for 2nd and 3rd molars) 
• 
Subject who has mixed dentition  
• 
Subject with periodontal disease  
• 
Subject with active caries 
• 
Subject with TMD symptoms   
• 
Subject has undergone pre-treatment with any orthodontic appliance 
3 months prior to the start of treatment 
• 
Subject has undergone any accelerated orthodontic treatment prior to 
or during treatment as part of this study 
• 
Subject has known allergy to latex or plastic  
• 
Subjects who are pregnant or will become pregnant during treatment  
Sites 
21 participating doctors in the US and UK.  
Sample Size 
215 subjects. 
Length of Study 
Approximately 4 years.  
Results 
Subject Enrollment 
• 
Started: 253 
o 178 female 
o 75 male 
• 
Completed: 215 
• 
Not completed: 38 
215 completed subjects were included in the data analysis which was 
conducted by Align’s own statisticians. These 215 subjects all had initial and 
final data points for analysis. Total treatment time was measured in days and 

refinement rate was measured as a percentage per cohort. No Adverse Events 
were reported.