A new trial looks at the effectiveness of digital direct bonding.
Orthodontics is rapidly advancing towards digitalization. One of the latest advancements is CAD/CAM indirect bonding, which utilizes digital technology to improve the precision of bracket placement. Despite the swift adoption of this new technology, limited studies have been conducted on the potential advantages of these procedures. Therefore, this new study is well-timed.
A team from Brazil did this trial. The Angle Orthodontist published the paper.
Eloisa Peixoto Soares Ueno et al. Angle Orthodontist: DOI: 10.2319/030624-179.1
What did they ask?
They did this trial to
“Compare the accuracy and chair time of placing self ligating brackets using direct bonding and CAD/CAM indirect bonding”.
What did they do?
The study team did a three arm parallel group randomised trial with a 1:1 allocation.
The PICO was.
Participants
Orthodontic patients with a Class I or half Class II occlusion with no severe crowding, bimax protrusion or indications for tooth extraction.
Interventions
- Group 1. Direct bonding
- Group 2. Indirect bonding on plaster models using transfer trays made with PVCS putty
- Group 3.Digital bracket positioning on a digital set-up with full digital flow using CAD/CAM printed trays.
The operator used Transbond adhesive for all the brackets.
Outcomes
Root parallelism and vertical difference between the posterior marginal ridges, using panoramic radiographs, digital and plaster models.
They recorded the duration of the bonding procedure with a digital timer to record the time from the initial acid etching to the complete adhesive polymerisation.
A single experienced operator did all the clinical procedures
They used a pre-prepared randomisation with allocation concealment done remotely.
Before they started the study, they did a sample size calculation. However, they did not state the effect size that they felt was clinically significant.
The team did the relevant parametric and non parametric tests between the three groups.
What did they find?
They randomised 15 patients to each study group. All the participants completed the trial. There were no differences in terms of age of the participants between the groups.
They did not detect any clinical differences between the three groups for occlusal plane measurement. There were no statistically significant differences found for marginal ridge levelling. Similarly, the ABO index scores for levelling showed no differences.
When they looked at treatment timing, they found differences in bonding times. Direct bonding took 56 minutes. Indirect bonding took 52 minutes. CAD/CAM bonding took 41 minutes. Data analysis revealed that the CAD/CAM bonding times were statistically significant from the other two techniques.
Their overall conclusion was
“The CAD/CAM indirect bonding was as effective as conventional methods, with a shorter chair time”.
What did I think?
While this study seemed interesting and relevant from a clinical standpoint, I had some concerns. First, it was a small study with low numbers in each group. We must consider that this results in the effect sizes being influenced by any outliers. This leads to high standard deviations and overall reduced confidence in the data. It was a shame that the team did not supply confidence intervals for their data. This must be a decision of the journal referees. These issues suggest that this study only serves as a good pilot study.
I had another concern about the reported clinical times. I couldn’t understand why these timings were so long. For example, the average time for direct bonding was 56 minutes. This was time from applying the etchant to the final curing of the adhesive. I would expect most orthodontists to take much less time for this process.
Furthermore, the study did not consider the extra technical time needed to prepare the indirect bonding.
I was also unsure about the wording of their conclusion. This was rather positive. Now I know that I can be rather negative about most things in life. But my conclusion would be
“There were no advantages of indirect bonding in terms of accuracy of placing brackets”.
Finally, this study suggests that we need to find the clear benefits of new technology in larger trials before jumping on the CAD/CAM train. But then I would say that!
Emeritus Professor of Orthodontics, University of Manchester, UK.
Emeritus Professor of Orthodontics, University of Manchester, UK.
Thanks for confirming what I have always thought – The 15 minutes saved by going the CAD CAM way will never justify the cost of the CADCAM system PLUS the extra time required to set up that system and Plan it. People will always justify indirect bonding which allows delegation but again the cost of that AND setting up each case far outweighs the efficiency of direct bonding. Furthermore, for about 30 years I used chemical cure – – which saved another 5 or 10 minutes with MINIMAL failures. I’ve watched clinicians switch from one indirect system to another continuously over the years – that alone in suggests inefficiency.
Postgraduate courses need to go back to teaching Direct bonding!
The Real Person!
The Real Person!
I cannot agree more John, and let us not forget the glue clean up around the brackets, practically impossible with indirect bonding, whatever the system. You could mask it with tooth coloured glue, but that doesn’t mean it goes away, very shabby, to clean that once the glue is set, add some more time as you need to pick up the handpiece, which I have never done with direct bonding. I have tried a few systems now and am increasingly sceptical. I don’t think we are there yet.
My conclusion, until someone shows me a system that actually does a clean and accurate job, I am sticking to direct bonding. In the famous words of Naolean Hill ” It takes half your life before you discover life is a do-it-yourself project.”