Alleged Treatment Time Representation
932 SDC alleges that the Invisalign website contains the statement, under the heading "Treatment Process - Invisalign vs Braces":
When comparing Braces vs Invisalign aligners, it's clear that the Invisalign system could deliver more benefits, from aesthetics and comfort through to oral hygiene and treatment time.2
(Braces Comparison Statement)
933 The Braces Comparison Statement is accompanied by additional text in footnote 2 (cited after the words "treatment time") which states:
2. Treatment time with Invisalign clear aligners completed finished 5 months faster sooner [sic] on average than treatment with fixed appliances braces.
- Gu, J et al. Evaluation of Invisalign treatment effectiveness and efficiency compared with conventional fixed appliances using the Peer Assessment Rating index, Am J Orthod Dentofacial Orthop February 2017; 151:259-66.
- Buschang, P et al. Comparative time efficiency of aligner therapy and conventional edgewise braces. Angle Orthodontist. Vol 84, No 3, 2014
934 SDC contends that the Braces Comparison Statement, when read in the context of the accompanying reference in footnote 2 to the selected journal articles, conveys the representation that teeth alignment with Invisalign aligners is faster than teeth alignment using traditional metal braces (Alleged Treatment Time Representation).
935 SDC submits that the Alleged Treatment Time Representation arises from the express comparison with braces in the heading on the Invisalign Website and the reference to the "benefit" of treatment time in the body of the statement, in the context of the additional text in footnote 2 that refers to Invisalign aligners completing treatment five months sooner than treatment with braces.
936 In my opinion, the Braces Comparison Statement conveys information about the potential benefits from Invisalign treatment, including aesthetics, comfort, oral hygiene and treatment time. The additional text which appears as footnote 2 to the Braces Comparison Statement is to the effect that the results of the Gu study and the Buschang study show that, for the cohorts in those two studies, treatment was completed an average of five months faster with Invisalign aligners than with braces.
937 I am of the opinion that the text of the Braces Comparison Statement and the additional text of footnote 2, when read in context, do not contain any statement to the effect that, in all cases, treatment with Invisalign aligners is faster than treatment with braces.
938 I accept Invisalign's submission that, at its highest, the representation conveyed by the combination of the Braces Comparison Statement and the additional text of footnote 2 is only that:
(a) treatment with Invisalign aligners could be faster than treatment with braces;
(b) the results of the two studies appearing in footnote 2 support the fact that treatment with Invisalign aligners could be faster, because the results of these two studies show that, on average, treatment with Invisalign aligners was completed five months faster than treatment with braces; and
(c) potential patients should choose the treatment process that will give them the best results taking into account their own circumstances.
939 The Braces Comparison Statement and the text of footnote 2 cannot be viewed in isolation from the "Treatment process - Invisalign vs Braces" webpage. Such material must be determined objectively and assessed within the entire context of the medium through which consumers engage with that material: TPG2020 at [25]; Luxottica at [49] per Griffiths J. When having regard to this material, in my view, it is clear that text which appears on that webpage has a material effect on the impression that the webpage leaves on a consumer viewing that webpage. In this regard, the webpage relevantly contains, in addition to the Braces Comparison Statement and the text of footnote 2, the following statements:
(a) "Start by seeking an expert opinion";
"The decision of Braces vs Invisalign Treatment rests on you and your doctor reviewing and discussing your:
• age and oral development
• individual case and the treatment needed for long-term oral health
• aesthetic preferences
• lifestyle and day to day routines
• cost/budget"
940 The above statements would, in my opinion, convey to the ordinary and reasonable consumer in the market for teeth straightening that the decision to undergo treatment with Invisalign aligners or braces is a decision which the consumer makes in consultation with an expert, and the selection of the type of treatment (Invisalign aligners or braces) is one which depends on the consumer's individual circumstances.
941 When viewing the "Treatment process - Invisalign vs Braces" webpage as a whole, I am of the opinion that the representation conveyed to the ordinary and reasonable consumer in the market for teeth straightening by the Braces Comparison Statement and footnote 2 is not that, in all circumstances, treatment with Invisalign aligners will be faster than braces, but rather that, in some circumstances, for some individuals, treatment could be faster (Conveyed Treatment Time Representation).
942 I am also not satisfied on the evidence that SDC has established the falsity of the Conveyed Treatment Time Representation and that treatment with Invisalign aligners is not faster than braces in some circumstances. The experts, Drs Chan, Mahony, Vlaskalic and Lai, were asked to express their opinion in respect to question 42 in the Joint Expert Report. This question was: "In your experience, is treatment with Invisalign branded clear aligners faster than treatment with traditional metal braces?". The experts subsequently gave evidence on this question in the expert conclave. Professor Dreyer also gave evidence, by way of the first Dreyer Affidavit, concerning the treatment time for patients using clear aligners, including Invisalign, and fixed appliances, in the context of giving evidence on his review of the four articles referred to above. Professor Dreyer was separately cross-examined on his evidence.
943 The experts' evidence varied greatly.
944 In the Joint Expert Report, Dr Mahony stated unequivocally that Invisalign was not faster than treatment with traditional braces. In the expert conclave, Dr Mahony similarly stated that his professional advice to all of his patients is that fixed braces will be more efficient or work in a shorter timeframe than Invisalign aligners. Dr Mahony explained in his affidavit that the reasons why treatment using braces is always, in his opinion, faster than treatment with Invisalign aligners, includes: compliance issues with patients wearing Invisalign aligners that do not occur with braces (by virtue of the fact that braces cannot be removed by the patient), and that it is possible to affect a greater range of movement with braces than with Invisalign aligners.
945 In the Joint Expert Report, Dr Chan opined that in some cases, such as open bite and deep bite cases, Invisalign can provide a faster treatment than traditional metal braces. However, in most pre-molar extraction cases, traditional braces will be more efficient.
946 Similarly, in Dr Chan's second affidavit, sworn 5 August 2022, Dr Chan stated that, unless the patient did not wear clear aligners as directed, it was not his experience that the treatment time for clear aligners was longer than treatment with conventional fixed braces. He said that, in a number of cases, treatment duration can in fact be shorter with the use of clear aligners, such as in the case of patients with a deep bite.
947 In Dr Chan's affidavit, sworn 6 May 2022, he stated that the choice of whether to use braces or clear aligners was based on a number of factors. Those factors included patient compliance (including whether the patient was able to wear clear aligners for a minimum of 20 to 22 hours per day) and logistical considerations (including whether the patient was able to return to the orthodontist or dentist every four to six weeks for adjustments to their braces, or every eight to ten weeks for reviews when using clear aligners).
948 In the expert conclave, Dr Chan was asked to comment on Dr Mahony's evidence that braces are quicker than clear aligner treatment. Dr Chan said that, in his experience, it is case dependent. Dr Chan provided a number of factors which went into this consideration, such as braces requiring more orthodontist visits (every four to six weeks) whereas, with clear aligners, that consultation can be stretched out to about eight weeks or sometimes ten weeks. Dr Chan explained that not all patients are able to attend for a consultation every four to six weeks. Dr Chan's evidence is that, given this, the decision of whether to recommend fixed applications or clear aligners is not just a clinical diagnosis, it is also a holistic approach having regard to what is more suitable for each patient.
949 In the Joint Expert Report, Dr Vlaskalic opined that physiology and intensity, duration and frequency of force dictate the velocity of tooth movement not the appliance per se. Dr Vlaskalic stated that the major difference between braces and Invisalign aligners is the treatment process. In the case of braces, once a diagnosis and treatment plan are performed, braces are able to be applied. In contrast, Invisalign aligners need to be programmed, manufactured and delivered. In the case of braces, if continuous arch mechanics are utilised, which Dr Vlaskalic said was the most common, the orthodontist may need to undo certain unwanted effects and this may take time. Dr Vlaskalic concluded with the statement that, largely, the treatment times are equivalent.
950 Dr Vlaskalic, told the Court during the expert conclave, that peer reviewed studies have shown that treatment duration for clear aligners and braces is very similar, but those studies really only considered mild to moderate cases of malocclusion. Dr Vlaskalic opined that the treatment duration can also be dependent upon the patient's individual circumstances, their level of compliance in attending their appointments, the practitioner's goals for the treatment and the practitioner's experience with the software and system for programming the mechanics into the aligners. Dr Vlaskalic further noted that the frequency with which clinicians asked their patients to wear aligners also made a sizable difference in terms of treatment duration.
951 In the first Dreyer Affidavit, Professor Dreyer opined that treatment time would vary depending on individual factors. Professor Dreyer stated that treatment duration with braces or clear aligners depended, in part, on the frequency of adjustments (of fixed appliances) or changes (of aligners) that were required. Professor Dreyer stated that treatment duration, with braces, is dependent on the frequency of "adjustments" performed when a patient attends an orthodontist's clinic to have adjustments made to their fixed appliance. Professor Dreyer's evidence was also that the same can be said in relation to the frequency of changes of all clear aligners, including Invisalign aligners. Professor Dreyer stated that, the more frequently an aligner or fixed appliance was changed, the greater the reduction in the duration of treatment.
952 In the Joint Expert Report, Dr Lai stated that he did not have sufficient experience with braces to be able to compare Invisalign aligners with braces.
953 I have considered the expert evidence in the opinions expressed in the Joint Expert Report in answer to question 42 and in the evidence given in the expert conclave by Drs Chan, Mahony and Vlaskalic. I prefer the expert opinions of Drs Chan and Vlaskalic to that of Dr Mahony. On the topic of treatment time, I found the evidence of Drs Chan and Vlaskalic to be more comprehensive than Dr Mahony's evidence in identifying factors which impact upon treatment time using traditional metal braces as opposed to Invisalign aligners. Drs Chan and Vlaskalic's evidence establishes that those factors include whether there is a deep bite or open bite case, the patient's ability to attend consultations with orthodontists to have adjustments made to their fixed appliance, patient compliance and the practitioner's goals for the treatment.
954 I also accept Professor Dreyer's evidence that treatment time will vary depending on individual factors, which includes the frequency of adjustments made to fixed appliances and the frequency of changes to aligners. The evidence of Drs Chan and Vlaskalic is consistent with Professor Dreyer's evidence. The evidence of Drs Chan and Vlaskalic, and Professor Dreyer establishes that Invisalign aligners could be faster than treatment with braces for some patients.
955 SDC also made submissions with respect to the expert evidence of Professor Dreyer, who was shown and commented on the Gu Article and the Buschang Article referred to in footnote 2 of the additional text accompanying the Braces Comparison Statement.
956 Professor Dreyer was also shown and cross-examined on the Lin Article which was tendered in evidence and marked exhibit 66. Professor Dreyer accepted that the Lin Article concluded that patients that were treated with Invisalign aligners required 4.8 months' longer treatment time than patients with braces. The substance of SDC's submission was that, due to deficiencies in the studies that were the subject of the Gu Article and Buschang Article, those articles should be given no probative weight on the question of whether or not Invisalign treats orthodontic conditions faster than braces. Instead, the Court should accept the findings of the Lin Article, which SDC characterised as containing more rigorous research findings.
957 The Buschang Article compared the time efficiency of Invisalign aligners compared to conventional braces. The research is now eight years old and involved a comparison with a now superseded version of Invisalign aligners, which is no longer supplied to consumers. The study involved a retrospective analysis of patients who had completed treatment.
958 The Gu Article is five years old and assesses patients who underwent orthodontic treatment between 2009 and 2014. Like the Buschang Article, this study compared treatment time with previous versions of Invisalign aligners against treatment time with braces. The study found that, compared to Invisalign aligners, conventional braces required 5.7 months' longer treatment duration.
959 Professor Dreyer was not asked to advise the Court what other articles were available that might bear upon the findings in the articles shown to him and whether there was any other research which contradicts the Gu Article and the Buschang Article. Professor Dreyer accepted, in cross-examination, that there was a "great deal" of published articles on the time required to conduct an orthodontic treatment program. Professor Dreyer also explained that the two articles which he was asked to opine on was only a small selection of the available academic literature on this topic. In the course of providing his evidence, Professor Dreyer did not conduct an independent literature review or meta-analysis of the research available in relation to the time efficacy of aligners.
960 Professor Dreyer's evidence referring to the Buschang Article and the Gu Article was challenged by Dr Ackerman. Dr Ackerman gave evidence that the findings in the Buschang Article were highly biased and the conclusions could not be relied upon. Dr Ackerman stated that the study in the Buschang Article involved a retrospective analysis of patients who had completed treatment. Dr Ackerman gave oral evidence that this type of research was lower on the evidence pyramid in terms of the persuasiveness and significance of the evidence. Dr Ackerman gave evidence that the results of the Buschang Article were likely to have been influenced by treatment planning bias, in circumstances where the criteria for treatment with braces or Invisalign aligners was not exposed or explained in the research. Dr Ackerman also stated that the Buschang Article suffered from further deficiencies. In Dr Ackerman's view, these deficiencies were that the Buschang study:
(a) had no control group;
(b) there was no "blinding" of the clinician; and
(c) there was no randomisation of the patients or their inclusion in the braces or clear aligners group.
961 Dr Ackerman also gave evidence that the results of the study in the Gu Article were subject to the following limitations:
(a) multiple braces systems (which were not disclosed) were used;
(b) multiple clinicians treated patients in both groups of the study; and
(c) the study did not state the criteria for deciding when the treatment was complete.
962 In the second Dreyer Affidavit, Professor Dreyer accepted that the Buschang Article and the Gu Article did not employ a perfect academic methodology. However, Professor Dreyer stated that similar deficiencies can be found in all clinical treatment studies. Professor Dreyer stated that while it is ideal to have patients be randomised into treatment groups in a clinical trial setting, to do so in circumstances where two different medical devices are used to correct malocclusion can be difficult and potentially unethical.
963 Professor Dreyer's evidence was that it was also difficult to implement a "control group" in a comparative clinical trial of the nature in which the Buschang study was conducted. This is also the case, in Professor Dreyer's view, for implementing "blinding" in order to reduce any bias which might arise from the researcher or patient knowing the treatment method allocated to them.
964 Professor Dreyer gave further evidence that, where it is not possible to implement randomisation, any possible bias that may arise towards one method of treatment over the other may be reduced if patients are selected with similar clinical features. Often this is reflected in a study's inclusion criteria. Professor Dreyer' evidence was that by limiting the selection criteria to records of patients with very similar pre-treatment conditions, the Buschang study, as much as possible, compared patients like for like that fit within the inclusion criteria. This made them candidates for either braces or clear aligners, subject to other considerations such as compliance. As a result, Professor Dreyer did not consider the absence of randomisation to be a flaw of the Buschang Article.
965 Professor Dreyer reviewed the Lin Article and accepted in cross-examination that:
(a) the purpose of the study was to measure the treatment time of patients treated with traditional braces compared to patients treated with the latest generation, as at 2022, of Invisalign aligners;
(b) one of the inclusion criteria of patients in the study was patients with mandibular crowding of 4mm or less;
(c) pre-treatment occlusion among patients assigned to the braces treatment group was more complex than that of patients assigned to the Invisalign Aligner Treatment group. The difference in complexity was statistically significant;
(d) patients treated with Invisalign aligners required 4.8 months' longer treatment time than patients treated with braces (despite the fact that the patients treated with braces had more complete occlusion to being with); and
(e) one of the authors of this study (Dr Peter Buschang) was the lead author of the 2014 Buschang Article.
966 The heading of the Lin Article described it as using a "randomized controlled trial" method. Professor Dreyer accepted, in cross-examination, that a randomised control trial reduces the risk of bias on the part of the researchers, including treatment planning bias. When asked whether Professor Dreyer accepted that the Lin Article involved a "randomised control" trial, he explained that it was a randomised trial but only to the extent that the participants in the study were selected then randomised. More particularly, Professor Dreyer's evidence was that the patients were selected because of particular characteristics associated with the position of their teeth, and then randomly assigned prior to treatment to either the braces group or the Invisalign aligner group for treatment. Professor Dreyer stated that, in the Buschang Article, Gu Article and Lin Article, the patients had been selected on basically the same characteristics. Professor Dreyer also accepted that the Lin Article was a prospective study as opposed to a retrospective study.
967 For the reasons given above, I found that Dr Ackerman was not a reliable witness and was not independent of SDC. As a consequence, Dr Ackerman's evidence is of no probative value.
968 I accepted the expert evidence given by Professor Dreyer and, in particular, his evidence that deficiencies may be found in all clinical treatment studies.
969 For this reason, I place greater weight on the expert evidence given by Drs Chan and Vlaskalic in the Joint Expert Report and the evidence which they gave in the expert conclave, which I have referred to above.
970 I place little weight on the Buschang Article and the Gu Article because of the deficiencies in those articles identified by Professor Dreyer. However, I reject SDC's submission that the Buschang Article and the Gu Article should be given no probative weight on the question of whether or not Invisalign treats orthodontic conditions faster than braces. The only evidence challenging the reliability of the Buschang Article and Gu Article was provided by Dr Ackerman, whose evidence I have not accepted. The cross-examination of Professor Dreyer did not establish that the deficiencies in the Buschang Article and the Gu Article warranted a conclusion that they should be given no probative value.
971 As to the Lin Article, I accept Professor Dreyer's evidence that the study in the article was not an entirely "randomised" controlled trial, as patients were selected because of particular characteristics associated with the position of their teeth. The Lin Article therefore has its own deficiencies. Moreover, the conclusions in the Lin Article - that the patients in the study treated with braces completed treatment 4.8 months earlier than those treated with Invisalign aligners - does not detract from a conclusion that treatment with Invisalign aligners is faster than braces in some circumstances. I am therefore not satisfied that the Lin Article establishes the falsity of the Conveyed Treatment Time Representation.
972 I am not satisfied, on the evidence, that SDC has established the falsity of the Conveyed Treatment Time Representation and that treatment time with Invisalign aligners is not faster than braces in some circumstances.