The
`Journal of
`Clinical Dentistry®
`®
`
`THE INTERNATIONAL JOURNAL OF ORAL CARE PRODUCT RESEARCH
`www.JClinDent.com
`2017
`
`Volume XXVIII
`
`Supplement
`
`Acquisition of a Digital Intraoral Scanning Device:
`
`An Examination of Practice Volume Changes and the
`Economic Impact via an Interrupted Time Series Analysis
`
`SENIOR EDITOR
`Robert C. Emling, EdD
`EDITORIAL BOARD
`Mauricio Montero Aguilar, DDS, MS
`Bennett T. Amaechi, BDS, MS, PhD, FADI
`Caren M. Barnes, RDH, MS
`Mozhgan Bizhang, Priv.-Doz. Dr.
`Annerose Borutta, Prof.Dr.med.habil.
`Robert L. Boyd, DDS, MEd
`Neil W. Brayton, DDS
`Kenneth H. Burrell, DDS, SM
`Mark E. Cohen, PhD
`Serge DiBart, DDS, DMD
`David Drake, MS. PhD
`Heinz Duschner, Prof.Dr.
`William Michael Edgar, PhD, DDSc, FDSRCS
`Denise Estafan, DDS, MS
`Robert V. Faller, BS
`Stuart L. Fischman, DMD
`Jane Forrest, EdD, RDH
`Rosa Helena Miranda Grande, DDS, PhD
`Anderson Takeo Hara, DDS, MS, PhD
`Lisa Harpenau, BS, DDS, MS, MBA, MA
`John J. Hefferren, PhD
`Steven Jefferies, MS, DDS, PhD
`Mark E. Jensen, DDS, PhD
`Carl J. Kleber, MSD, PhD
`Israel Kleinberg, DDS, PhD, DSc
`Karl-Heinz Kunzelmann, Prof. Dr., Dr. habil
`Frank Lippert, MSc, PhD
`Jonathan Mann, DMD, MSc
`Kenneth Markowitz, DDS
`Milton V. Marshall, PhD, DABT
`Jeffery L. Milleman, DDS, MPA
`Kimberly R. Milleman, RDH, BSEd, MS
`Pier Francesco Porciani, MD, MScD
`Howard M. Proskin, PhD
`Mark S. Putt, MSD, PhD
`Bruce R. Schemehorn, MS
`Jon B. Suzuki, DDS, PhD, MBA
`Jason M. Tanzer, DMD, PhD
`Norman Tinanoff, DDS, MS
`Louis Zalman Glick Touyz, BDS, MSc(Dent),
`MDent(Perio&OralMed)
`Henry O. Trowbridge, DDS, PhD
`Richard I. Vogel, DMD
`Anthony R. Volpe, DDS, MS
`Paul Warren, LDS
`Clifford W. Whall, Jr, PhD
`Anthony E. Winston, BSc
`Wayne T. Wozniak, PhD
`Stefan Zimmer, Prof. Dr. med dent.
`Avi Zini, BScMed, DMD, MPH, PhD
`PUBLISHER
`Stephen M. Siegel
`
`The Journal of Clinical Dentistry (ISSN 0895-8831) is published by Professional Audience Communications, Inc., P.O. Box 39486, Charlotte, NC 28278.
`POSTMASTER; Send address change to P.O. Box 39486, Charlotte, NC 28278.
`Copyright © 2017 by the YES Group, Inc. All rights reserved. No part of this publication may be reproduced without written permission from the publisher.
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`Align-1091_00116005
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`Inv. No. 337-TA-1091
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`JX-0084
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`Align Ex. 2010
`3Shape v. Align
`IPR2019-00157
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`The Journal of Clinical Dentistry has been accepted for inclusion in the Index
`to Dental Literature/MEDLINE on the NLM MEDLARS system, the BIOSIS,
`SCISEARCH, BIOMED, and EMBASE databases, Current Contents/Clinical
`Medicine, and the Automatic Subject Citation Alert.
`The Journal of Clinical Dentistry is dedicated to the publication of significant
`clinical and applied dental research and reviews. The publication of this
`Supplement in no way implies an endorsement of the products mentioned herein
`by The Journal of Clinical Dentistry, its Editors, Editorial Board or the Publisher.
`
`The Journal of Clinical Dentistry is printed on recycled paper.
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`Acquisition of a Digital Intraoral Scanning Device:
`An Examination of Practice Volume Changes and the
`Economic Impact via an Interrupted Time Series Analysis
`
`Michael M. Mackay, PhD
`Statistical and Methodological Consultant
`The University of Memphis College of Education
`Memphis, TN, USA
`
`Mohammad Fallah, BSD, MSD
`Associate Clinical Professor of Orthodontics
`University of the Pacific Arthur A. Dugoni School of Dentistry
`San Francisco, CA, USA
`
`Tiffany Danyal, DDS
`General Practice
`Clarkston, MI, USA
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`Acquisition of a Digital Intraoral Scanning Device:
`An Examination of Practice Volume Changes and the
`Economic Impact via an Interrupted Time Series Analysis
`Michael M. Mackay, PhD
`Statistical and Methodological Consultant
`The University of Memphis College of Education
`Memphis, TN, USA
`
`Mohammad Fallah, BSD, MSD
`Associate Clinical Professor of Orthodontics
`University of the Pacific Arthur A. Dugoni School of Dentistry
`San Francisco, CA, USA
`
`Tiffany Danyal, DDS
`General Practice
`Clarkston, MI, USA
`
`Abstract
`• Objective: To evaluate the impact of digital scanning in general dental practices and orthodontic practices to determine the percentage of lift,
`i.e., the percent increase in gross receipts, of Invisalign® treatment starts following the introduction of an iTero® intraoral scanner.
`• Methods: An interrupted time series analysis was conducted on 48 months (24 pre- and 24 post-scanner introduction) of Invisalign receipt
`data from 1,871 general practitioner (GP) and orthodontic practices located worldwide. Analyses also explored the presence of a longer shift
`in the trend of monthly Invisalign receipts after scanner introduction (i.e., pre-post slope change), and projected the impact of the introduction
`of the scanner within a specific subset of practices (n = 319) that represented North American GPs with low initial practice volumes (i.e., 5 or
`fewer receipts in the 12 months prior to acquiring the scanner).
`• Results: For the entire sample, introduction of the iTero intraoral scanner at month 25 showed a significant and abrupt increase in receipts for
`Invisalign therapy (b = 0.49; p < 0.001). When compared to the counterfactual regression line prediction without the scanner, in month 25
`Invisalign practice receipts increased from the predicted value of 2.38 to 2.88, an increase of 20.71%. When the analysis was conducted using
`only low-volume GP practices in North America, the introduction of the scanner at month 25 also led to a significant and abrupt increase in
`practice receipts (b = 0.28; p < 0.001), and this increase was still evident 24 months after scanner introduction.
`• Conclusion: The results show that acquiring an iTero intraoral scanner as a precursor to Invisalign therapy is associated with a significant
`increase in Invisalign practice receipts. When projected across the first 12 months, this increase amounts to an additional 5.92 receipts for the
`entire sample (i.e., 1,871 GP and orthodontic practices worldwide) and an additional 3.41 receipts for the subset of 319 low-volume, North
`American GPs.
`
`(J Clin Dent 2017;28(Suppl):S1-5)
`
`Introduction
`Orthodontic treatment and prosthodontic care depend on successful
`completion of an intermediate step, whereby the clinician must
`accurately capture and replicate the intraoral structures of the patient.1,2
`The involved process, however, is complex and multifactorial.
`Elastomeric materials such as polyvinylsiloxane (PVS) or polyether
`have traditionally been used to accomplish the impression process at
`the center of this indirect technique, yet have been superseded by digital
`intraoral scans (e.g., iTero® intraoral scanners, Align Technology,
`Inc., San Jose, CA, USA) for a variety of reasons that include their
`accuracy, the efficiencies provided to the members of the restorative
`team, and their utility throughout a digital workflow.3,4
`This growing adoption of iTero digital scanning by dental
`professionals worldwide has already produced more than 1.2 million
`restorative scans over 2.7 million orthodontic scans (Internal data;
`Align Technology, Inc.), and promises to increase as the technology
`
`is integrated within workflows that support restorative dentistry, implant
`diagnostics, treatment planning, and Invisalign® therapy (Align
`Technology, Inc., San Jose, CA). The interoperability of iTero scanners,
`yielding an “open system” stereolithographic file, enables the scans
`to be integrated within numerous third-party providers and practice
`management solutions. Additionally, new generations of dental
`practitioners have shown a bias toward dental technologies such as
`iTero that are intuitive to their experiences as users of digital solutions
`for their lives as consumers.5,6
`Expediency is a fundamental advantage of the digital impression
`process.7 From the procedural standpoint, digital scanning affords a
`simple solution for chairside technical challenges such as voids, tears,
`gaps, distortions, and the like that are often associated with PVS or
`polyether analog impressions. As a result, digital impressions have
`demonstrated excellent accuracy (i.e., as measured by internal fit and
`
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`S2
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`The Journal of Clinical Dentistry
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`Vol. XXVIII, Supplement
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`accessible marginal inaccuracy) that results in fewer rejections in
`Invisalign scans and greater efficiency in the cementation appointment,
`with fewer remakes for the dental laboratory and faster seating for
`the practitioner.3,4,8
`Digital intraoral scanners afford a superior patient chairside
`experience as well, eliminating discomfort to the patient, difficulty
`breathing, gagging, and similar concerns inherent to a conventional
`dental impression.9 The digital capture of the intraoral environment
`also enables the clinician to present during patient consultation a
`simulation of the projected outcome of Invisalign therapy (i.e.,
`Invisalign® Outcome Simulator, Align Technology, Inc., San Jose,
`CA) and thereby serve as a catalyst for patient acceptance of proposed
`orthodontic treatment (Figure 1). This is critical in the contemporary
`
`Figure 1. Simulated treatment outcome achieved through Invisalign therapy (Invisalign
`Outcome Simulator, iTero Element, Align Technology, Inc., San Jose, CA).
`practice, where the patient is an informed consumer with access to
`resources regarding the expense, duration, and steps involved in a
`successful treatment outcome. By displaying chairside for the patient
`how his or her dentition will appear following treatment, the clinician
`is able to conduct patient education in real time, motivate the patient
`to consider treatment, and to adjust the treatment plan “live” and
`incorporate the patient’s feedback in the treatment plan sent to Align
`Technology, Inc. Thus, iTero scanners have assumed a larger role in
`the contemporary dental practice, and their impact in driving Invisalign
`case acceptance is similarly increasing in a quantifiable manner.
`Based on these trends, the following analyses were undertaken to
`evaluate the impact of digital scanning on Invisalign therapy starts in
`the general dental practice (GP) and orthodontic practice (Ortho) to
`determine the “lift,” i.e., the percent increase in gross receipts, witnessed
`in Invisalign treatment, following the introduction of the iTero intraoral
`scanner. The analyses assessed three research questions:
`1) Does the introduction of the iTero scanner lead to an abrupt
`increase in Invisalign practice receipts at the time of scanner
`introduction?
`2) Is there a change in the monthly trend of Invisalign practice
`receipts from pre- to post-scanner introduction?
`3) When examining only North American GPs with low initial
`volume of practice receipts (i.e., 5 or fewer in the 12 months
`prior to scanner introduction), does the acquisition of the iTero
`scanner lead to an abrupt increase in practice receipts?
`
`Materials and Methods
`
`Dataset Description
`Global data were mined and included all Invisalign customers who
`purchased an iTero scanner. This dataset represented 1,871 GP and
`orthodontic practices worldwide (31% GP, 69% orthodontic; 84.40%
`North America, 11.11% Europe/Middle East, 4.22% Asia Pacific, 0.27%
`Latin America). Practice receipt data for Invisalign were collected objectively
`via instrument-driven electronic reporting; thus, the validity and reliability
`of the data were assured. Practices acquired the iTero intraoral scanner
`at any point in time between January 2013 and April 2015.
`Data were structured to represent the number of Invisalign receipts
`each month prior to iTero scanner introduction (i.e., from 24 months
`prior to 1 month prior) and post-introduction (i.e., from 1 month
`post to 24 months post). Due to the fact that practices acquired the
`scanner at any time during the year, the data time points are not
`connected to any specific month. In other words, the actual calendar
`month representing scanner introduction differs across the practices,
`and the data time points are not associated with specific calendar
`months. Thus, any seasonal effects that may affect Invisalign practice
`receipts could not be estimated in the current analyses, and potential
`history or cohort confounding effects were unlikely due to the varying
`month of scanner introduction.
`
`Identification of Model
`Data were analyzed using a segmented regression approach in which
`an abrupt change in practice receipts was hypothesized at month 25,
`the month representing scanner introduction. The hypothesis was
`made a priori (i.e., before analysis) to avoid capitalizing on chance
`relationships in the data.10 Before model identification, the pre-scanner
`introduction time series data were evaluated to ensure normality and
`homoscedasticity.11
`The initial model included the following terms:
`
`Yt = b0 + b1 (time) + b2 (intervention) + b3 (time_after_intervention) + e
`
`whereby
`b0 represented the constant (i.e., initial level of receipts) for the
`pre-scanner-introduction data;
`b1 represented the slope of the pre-scanner-introduction time series;
`b2 represented the change in receipts at the introduction of the
`scanner;
`b3 represented the change in slope between pre- and post-scanner
`introduction; and
`e represented the estimate of error (i.e., residual).
`
`In this model, the significance of the b2 term assessed the presence
`of an abrupt increase in Invisalign practice receipts at the time of
`iTero scanner introduction, and the significance of the b3 term assessed
`the presence of a longer shift in the trend of Invisalign receipts from
`pre- to post-scanner introduction.
`Time series data may exhibit autocorrelations that can downward-
`bias regression standard errors and result in a Type I error or exaggerated
`significance.12,13 Thus, before parameter estimates were made with the
`model, an iterative model identification process was employed whereby
`1) autocorrelation and partial autocorrelation plots of pre-scanner
`data were visually examined; 2) if autocorrelation was found, the
`model was adjusted for autocorrelation by conducting a Prais-Winsten
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`AR(1) GLS regression; 3) the results of the Prais-Winsten regression,
`specifically the produced Durbin-Watson statistics, were examined to
`determine if the autocorrelation was adequately accounted for; and
`4) autocorrelation and partial autocorrelation plots of regression
`residuals were examined one final time to assess any lingering
`autocorrelation.11,14
`For the analysis relating to Research Question 1, which used the
`entire sample of 1,871 GP and orthodontic practices, autocorrelation
`and partial autocorrelation plots revealed a slow decay in
`autocorrelation, with significant autocorrelation at one, and possibly
`two lags. A Prais-Winsten regression was conducted, and the Durbin-
`Watson statistic showed a decrease from 1.11 (p < 0.01) to 2.09
`(p = n.s.), signifying that no remaining autocorrelation was present.15
`A visual inspection of autocorrelation and partial autocorrelation
`plots of regression residuals confirmed this as well.
`For the analysis relating to Research Question 2, which used the
`subsample of 319 North American GPs with low initial volume of
`practice receipts (i.e., 5 or fewer in the 12 months prior to scanner
`introduction), autocorrelation and partial autocorrelation plots revealed
`no significant lags and the pre-intervention slope was not significantly
`different from zero, indicating a flat regression line (see Table II and
`Figure 3). As a result, a traditional linear regression analysis was
`conducted on this subsample.
`
`Results
`Research Question 1: Does the Introduction of the iTero Scanner Lead
`to an Abrupt Increase in Invisalign Practice Receipts at the Time of
`Scanner Introduction?
`As Table I shows, in this analysis all predictors were significant at
`p < 0.001 except for time after intervention (timeafterint), which was
`non-significant at (p = 0.832). As a result, the model was reduced to the
`following parameters: Y’ = 1.4839 + .0360 (time) + .4936 (intervention).
`As Figure 2 shows, at month 1, the number of Invisalign practice
`receipts was 1.48 and the number of receipts increased through
`month 25, the month of the scanner introduction, at which point
`there occurred an abrupt increase in Invisalign receipts. To assess
`the extent of the increase, receipt estimates were calculated at month
`25 using the counterfactual regression line (i.e., the regression line
`
`before the introduction of the scanner, expressed as the dotted blue
`line in Figure 2) and compared to the receipts estimated by the entire
`regression equation (i.e., the equation that included post-scanner
`introduction data, expressed as the solid black line in Figure 3).
`The number of Invisalign receipts as predicted by the counterfactual
`regression line at time 25 is: Y’ = 1.4839 + .0360 (25) = 2.3839. The
`number of practice receipts at time 25 as predicted by the full model
`is: Y’ = 1.4839 + .0360 (25) + .4936 (1) = 2.8775, signifying a 20.71%
`increase in practice receipts at the time of the introduction of the
`scanner.
`
`Figure 2. Time series plot showing receipt increase at month 25. Red line denotes
`introduction of the iTero intraoral scanner.
`
`Research Question 2: Is There a Change in the Monthly Trend of
`Invisalign Practice Receipts from Pre- to Post-scanner Introduction?
`In the regression model, parameter b3 represents the change in slope
`between pre- and post-scanner introduction. This parameter was
`estimated at 0.001 (p = 0.832), indicating that the pre- and post-scanner
`slopes do not differ significantly from each other. A visual inspection
`of the time series data (Figure 3) confirms that the two slopes are
`essentially identical. Thus, the results show that the initial increase of
`0.49 practice receipts at the time of scanner introduction is maintained
`
`AlliTeroData
`time
`intervention
`timeafterint
`_cons
`
`Table I
`Results of Analysis of 48 Months of iTero Intraoral Scanner and Invisalign Practice Receipts
`Coef.
`Std. Err.
`t
`p
`95% Conf. Interval
`0.36033
`0.0033818
`10.66
`0.000
`0.0292174
`0.0428485
`0.04936223
`0.0602825
`8.19
`0.000
`0.3721308
`0.6151138
`0.0010874
`0.005088
`0.21
`0.832
`-0.0091668
`0.0113417
`1.483883
`0.0498177
`29.79
`0.000
`1.383482
`1.584284
`
`time = slope pre-scanner intervention; intervention = introduction of the intraoral scanner at month 25; timeafterint = change in slope pre- and post-scanner
`introduction; _cons = regression constant.
`
`NASVGPsOnly
`time
`intervention
`timeafterint
`_cons
`
`Coef.
`-0.0006474
`0.2838344
`0.0013848
`0.1121939
`
`Table II
`Results of Analysis on Low-Volume North American GPs
`Std. Err.
`t
`p
`0.0013491
`-0.48
`0.634
`0.0264486
`10.73
`0.000
`0.0019079
`0.73
`0.472
`0.019277
`5.82
`0.000
`
`95% Conf. Interval
`-0.0033664
`0.0020716
`0.2305309
`0.337138
`-0.0024604
`0.0052299
`0.0733436
`0.1510442
`
`time = slope pre-scanner intervention; intervention = introduction of the intraoral scanner at month 25; timeafterint = change in slope pre- and post-scanner
`introduction; _cons = regression constant.
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`Vol. XXVIII, Supplement
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`coverage crowns, fixed partial dentures, trays, mouth guards, and for
`various implant procedures in both the diagnostic and execution phases
`of treatment. The present study’s results, therefore, provide an
`underestimate of the true overall economic benefit of adopting an
`iTero scanner, and future research should examine the economic benefit
`of the scanner with respect to additional procedures.
`The present study also explored whether there was a change in the
`monthly trend (i.e., slope) of Invisalign practice receipts from pre- to
`post-scanner introduction. The results reveal no significant change in
`slope between pre- and post-scanner introduction (b = 0.0011; p = 0.832);
`the post-scanner trend, shown in black in Figure 2, is not different
`from the trend prior to scanner introduction, shown in blue. Both
`slopes show a steady increase, indicating that the number of practice
`receipts is increasing throughout the entire 48 months represented in
`the data set, and that practitioners will see an 11.85 (17.64%) increase
`in volume receipts over the 24 months after acquiring the scanner.
`We urge readers to use caution when interpreting this finding because
`the amount of volume increase is moderated by initial practice volume.
`As discussed below, results relating to Research Question 3 show that
`North American GP practices with low initial volume (< 5 annually)
`do not exhibit the steadily increasing slope, and therefore have a different
`projected volume change.
`The third goal of the present study was to explore the projected
`impact of the iTero scanner on monthly Invisalign receipts for low-
`volume GP practices in North America. Consistent with Research
`Question 1, the results show a significant abrupt increase in practice
`receipts at the time of scanner introduction (b = 0.2838; p < 0.001)
`that remains non-changing across time (i.e., flat slope). When projected
`to 12 months post-scanner introduction, this increase represents a
`change of 3.41 additional receipts, representing an annual increase of
`$18,755, and suggesting that the initial financial investment in the
`scanner would lead to a return on investment in the second year of
`using the scanner. It is worthwhile to mention that this estimate is
`only accurate if the scanner is solely used for Invisalign treatments.
`As discussed above, iTero scanners have numerous applications beyond
`Invisalign treatments, suggesting that practitioners would see a quicker
`return on investment if the scanner was used for multiple purposes.
`
`Limitations and Future Directions
`One avenue for future research has been identified above: studies
`should explore the economic benefits of the adoption of iTero scanners
`with respect to additional applications of the scanner, such as veneers,
`crowns, and dentures. A comprehensive evaluation of the lift across
`all procedures performed with the scanner would provide a much
`more accurate estimate of the true economic impact of purchasing
`an iTero scanner.
`As more data become available over time, it will be worthwhile to
`re-conduct these analyses. Additional time periods will serve to provide
`more accurate parameter estimates, in particular the pre- and post-
`scanner trends. The analysis using all iTero users showed an increasing
`trend in receipts across all 48 months of data, whereas the analysis
`using only small volume North American GPs showed a stationary
`trend across the same time period. It is possible that this difference is
`a statistical anomaly that will disappear if more time points are included
`in the analysis.
`Future research should also examine the specific reasons the
`introduction of the iTero scanner leads to an abrupt increase in practice
`
`Figure 3. Time series plot showing receipt increase for low-volume, North American GPs.
`Red line denotes introduction of the iTero intraoral scanner.
`
`across time. When projected across the first 12 months after scanner
`acquisition, this amounts to 5.92 more practice receipts, a 19.11% increase
`over the expected volume projected via the counterfactual line.
`
`Research Question 3: When Examining Only North American GPs
`with Low Initial Volume of Practice Receipts (i.e., 5 or Fewer in the 12
`Months Prior to Scanner Introduction), Does the Introduction of the
`iTero Scanner Lead to an Abrupt Increase in Practice Receipts?
`Table II presents the results of the regression analysis for this subset
`of GPs. In this model, the only significant parameters were the constant
`(b0 = 0.1122; p < 0.001) and intervention (b2 = 0.2838; p < 0.001); thus,
`the regression model was reduced to: Y’ = 0.1122 + 0.2838 (intervention).
`As Figure 3 shows, the number of estimated receipts for any month
`prior to scanner introduction was 0.11 (p < 0.001) and the introduction
`of the scanner was associated with a significant increase in receipts
`(b = 0.28; p < 0.001). The pre-scanner slope was not significant
`(p = 0.634) and neither was the change in the slopes from pre- to post-
`scanner introduction (p = 0.472). Similar to the results of Research
`Question 2, the findings suggest that scanner introduction is associated
`with an increase of 0.28 practice receipts, which remains steady across
`time and amounts to 3.41 more receipts annually when compared to
`the volume projected by the counterfactual line.
`
`Discussion
`The results of Research Question 1 show that at the time of scanner
`introduction there was a statistically significant growth in practice
`receipts (b = 0.4936; p < 0.001), representing a 20.71% increase.
`This increase remained steady across time (i.e., there is no pre-post
`slope change), suggesting that the adoption of the iTero scanner
`translates to an economic benefit for practitioners: when projected
`across the first 12 months, it is associated with an increase of 5.92
`receipts and, assuming a $5,500 average cost of an Invisalign case
`(internal data, Align Technology, Inc.),16 amounts to an annual
`increase of $32,560.
`The findings further suggest that a practitioner’s initial monetary
`investment in the iTero scanner (MSRP = $29,999) would lead to
`returns within about a year if a practitioner used the scanner to only
`perform Invisalign procedures. In reality, the iTero scanner has
`applications in numerous restorative procedures, such as veneers, full-
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`receipts. A strong hypothesis is that the increase is due to the scanner’s
`capacity to preview the potential outcome of Invisalign therapy to a
`patient during the consultation phase by use of the Invisalign Outcome
`Simulator. If this is true, then a similar increase in receipts would be
`evident with other virtual simulations that are not specific to the iTero
`scanner. Alternatively, the increase could be due to reasons that are
`specific to the iTero scanner, such as clinicians’ satisfaction with the
`precision-fit of aligners generated by the scan, or scanner efficiency
`and ease-of-use. Knowing which of these factors is the primary driver
`of the increase in Invisalign practice receipts would provide valuable
`insights for dental professionals contemplating the incorporation of
`iTero within their practices.
`Another possible reason for the increase in practice receipts may
`be attributable to a self-selection effect. The initial purchase of the
`iTero scanner signals motivation in the practitioner to use the scanner.
`Practitioners who bought the scanner had the intention to perform
`more procedures and, as a result, the exhibited increase in practice
`receipts may be partly due to practitioners simply scheduling more
`Invisalign consults. If this is the case, then the receipt increase determined
`in the present study is not solely a function of the scanner but also
`likely a byproduct of practitioners having more consults in the first
`place. The dataset used in this study did not contain data about the
`number of consults each practitioner performed per month, making
`it impossible to determine the strength of the self-selection effect. It
`is our hope that future studies examine the effect of acquiring an iTero
`scanner while adjusting for increases in consults and practitioner
`motivation. Alternatively, future studies could employ a control group
`of practitioners who perform Invisalign procedures without the use
`of an iTero scanner.
`
`Conclusion
`This study’s results demonstrate that the adoption of an iTero
`intraoral scanner is associated with a statistically significant increase
`in Invisalign-related practice receipts in the month directly following
`scanner introduction. When projected across the first 12 months after
`the introduction of the scanner, this amounts to an annual volume
`lift of 5.92 receipts and translates to an estimated $32,560. Similarly,
`when the analysis is conducted using only low-volume North American
`GPs, there is a significant increase of 3.41 receipts over the first 12
`months that amounts to $18,755. Overall, the findings suggest
`practitioners stand to see their initial financial investment in the scanner
`lead to a return on investment in either the first or second year of
`using the scanner.
`
`Acknowledgement: This study was supported through a grant from Align Technologies, Inc.
`Conflict of Interest: The authors declare no financial or non-financial interest in the
`company or the materials cited herein, and acknowledge receipt of an expense stipend
`for composition of this analysis.
`
`For correspondence with the authors of this paper, contact Dr.
`Michael Mackay – michael1983mack@gmail.com.
`
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