25 The word "misleading" is well known to the law as it is a word used in a central provision of the Trade Practices Act 1974 (Commonwealth) and in the Fair Trading Act 1999. Although the courts have been reluctant to "search for other words to replace those in the section itself"[11] there appears to be general acceptance that, in order to be "misleading" conduct must convey "a meaning which is inconsistent with the truth"[12] and thereby is likely to lead a person into error.[13] Whether an advertisement is misleading does not require proof of intention, although intention may be relevant. Further, the question is not whether a particular person was misled; whether the conduct (or advertisement) is misleading is a matter for the court or tribunal assessing the matter. In making this assessment it is necessary to look to the audience and ask whether the conduct complained of was to them misleading.[14]
26 I find that the advertisement was not misleading. Although the advertisement was provocative in tone - possibly even alarmist - it has not been demonstrated that it was inconsistent with the truth. Based upon my earlier findings it can be said that the advertisement makes assertions about causal links that are not yet justified by the scientific evidence. However the true position, as currently informed by the scientific evidence, is not that there is no such causal links. On the contrary, the true position, as informed by the scientific evidence, is that there may well be causal links, not only because of the existence of associations, but also because there exists reasonable hypotheses as to why there could be causal links. Hence I am not prepared to conclude that the central message in the advertisement was inconsistent with the truth.
27 I return to Professor Bartold's assent to the proposition that it should be sufficient for those involved in the dental profession to state that "periodontal health is very important for an individual's systemic health". If that is the true position (and I accept the evidence that it is), could it be said that the advertisement was misleading in the sense that it caused, or was likely to cause, the reader into making an error? I think not. It is possible that a reader of the advertisement, concerned about some general health issue (such as lung disease or heart disease) might seek dental treatment in relation to their gums when, but for the advertisement, they may not have sought such treatment. But if periodontal health is "very important" for an individual's systemic health, it is difficult to see how the effect of the advertisement would be to cause that person to make an error in seeking dental treatment in such circumstances.
28 It is true that the advertisement uses attention-grabbing, even alarmist, language. But does this make the advertisement misleading?
29 The advertisement was not some official publication upon which members of the public could be expected to place considerable weight. It was an advertisement. It was published in a popular magazine, alongside stories such as "Elle talks about motherhood the second time around", "Dr Death - my mum was murdered by our family GP" and "Sharon Stone's Fight for Life - I had to live for my son". It was published together with a series of advertisements for drugs or beauty treatments. This context means that the reader is likely to take claims about the effect of treatment for gum disease with a grain of salt. We must give members of the public some credit for being sceptical about the claims made in advertisements. After all no-one can escape the constant barrage of advertisements; people get used to puffery and make allowances for it.
30 Advertising, like all other conduct in trade or commerce, is susceptible to challenge under section 52 of the Trade Practices Act if it is misleading. In this context courts have recognised that a degree of latitude is to be allowed by reason of the nature of advertising as a medium. Lockhart J has called for a "robust approach"[15] and other courts have recognised the concept of "puffery". For example, in General Newspapers Pty Ltd v Telstra Corp[16] the court observed that puffery is part of the ordinary stuff of commerce. And in Pappas v Soulac Pty Ltd[17] Fisher J commented that: