August 27, 2014

A systematic review that shows TADS are effective!

A systematic review that shows TADS are effective!

In my last two blog posts I have outlined the findings of two systematic reviews which I felt did not provide high levels of evidence. This week I am going to review a recent Cochrane review, but I shall declare an interest because I am a co-author.  A review of this paper has also been published in the excellent Dental Elf (they have clearly not had a holiday because they are ahead of me!).

Reinforcement of anchorage during orthodontic brace treatment with implants or other surgical methods

Safa Jambi, Tanya Walsh, Jonathan Sandler, Philip E Benson, Richard M Skeggs, Kevin D O’Brien

Cochrane Database of Systematic Reviews 2014, Issue 8. Art. No.: CD005098. DOI: 10.1002/14651858.CD005098.pub3.

This was published in the Cochrane library and is, therefore, relatively accessible. This review is an update of a previous review. When you sign up to carry out a Cochrane review you also promise to update the review periodically. This ensures that reviews remain contemporary, unlike reviews that are published in academic journals. The lead author, Safa Jambi, “volunteered” to update this review as part of her PhD that she carried in Manchester. This review satisfies the exacting standards of the Cochrane Collaboration and only included trials, importantly no retrospective investigations are included. It, therefore, provides a very critical assessment of the evidence. We followed usual Cochrane protocols to ensure that the literature search was extensive. We identified 15 trials that reported on data from 561 patients. Ten of these studies compared surgically assisted anchorage with traditional methods of anchorage reinforcement, such as headgear and palatal arches. We divided these studies into those that investigate palatal implants or temporary anchorage devices. We looked at several outcome measures but the most relevant was the mesio-distal movement of the upper molars. We selected this outcome because it was the most commonly measured and was relevant to the immediate effect of the anchorage device. However, I feel that a more important outcome would have been the final result of the treatment. This is because it provides important clinical information that may be relevant to both the orthodontist and the patient. This should certainly be considered when designing further studies.

The results suggested that the use of surgically assisted anchorage devices was more effective than conventional methods. I have taken the relevant data from the review and included it in this table.

Quality levelDefinition
HighWe are very confident that the true effect is close to the estimate of the effect
ModerateWe are moderately confident in the effect estimate
LowOur confidence is the effect estimate is limited
Very lowWe have little confidence in this estimate
Importantly, when we evaluated the quality of the evidence using the GRADE approach, we found that this was moderate. This was because most of the studies were at some risk of bias due to factors such as lack of blinding and concealment of randomisation. This is a very exacting assessment and to some extent may be considered to be very harsh. However, it sets a standard and we need to interpret the data bearing this in mind.

 Does this review influence clinical practice?

I will concentrate on the results for TADS, as palatal implants are not so commonly used. The review shows that there is evidence that TADS are effective. But you need to review the evidence from the review. This previous blog post covers some issues with interpretation of data.  You need to consider whether the effect size of 2mm is clinically useful. Then you need to look at the confidence intervals (-2.7, -1.77). These are narrow suggesting that the degree of uncertainty in the data is low. Finally, you need to consider the risk of bias and the GRADE assessment as being moderate. When I have evaluated the findings of the review, I feel that these results are clinically useful. I have not been an adopter of TADS until now and I certainly will be using TADS in preference to headgear, palatal arches and any other conventional sources of anchorage.

 Final comment

One other important matter that I would like to raise is that we have been using TADS for at least five years, but in the absence of evidence that they are effective. I cannot help feeling that trials should have been done as part of product development and testing. While the results of studies have ultimately been favourable for TADS, it would have been ideal if the orthodontic companies and their clinical key opinion leaders paused and tested their products before release and widespread use by non critical orthodontists. Jambi S,, Walsh T,, Sandler J,, Benson PE,, Skeggs RM,, & O’Brien KD (2014). Reinforcement of anchorage during orthodontic brace treatment with implants or other surgical methods Cochrane Database of Systematic Reviews DOI: 10.1002/14651858.CD005098.pub3

Related Posts

Have your say!

  1. Dear Professor O’Brien,
    Thank you for this fantastic and contemporary orthodontic blog which provides many inspiring ideas for evidence based dental practice. I especially enjoy the focus on clinically relevant and patient orientated outcomes. I wanted to highlight the mistake in the quoted confidence intervals for mid-palatal implants which I think should be -2.31, 0.26 therefore providing much less conclusive evidence of their benefit when compared to conventional anchorage.

Leave a Reply

Your email address will not be published. Required fields are marked *