Recently, I wrote a blog post and then shot a video ranting about Dr. Lawrence Andrews and the virtues of having a prescription. Now I decided to write a ‘so-what’ blog post trying to answer a question what prescription to use? I’ll keep it short…
In order to answer this question I suggest to look at this interesting study carried out in the United Kingdom in 2015. It is published in the Angle Orthodontist, thus you can download it for free without violating any copyright.
A study from the UK on Roth vs MBT prescription
In their introduction the authors highlight that MBT and Roth prescriptions are the two most commonly used in the UK. As a result, the authors aimed to find out if there were any significant differences in the final inclination of the upper and lower anterior teeth of patients treated with these two bracket prescription. For this matter they selected posttreatement study models from 20 Roth and 20 MBT patients and laser-scanned the final crown inclinations of UL1, UR3 and LR1.
The inclusion criteria were the following:
- Patients younger than 20 y.o. to start the treatment
- Bilateral upper arch extractions
- A 0.019 x 0.025-inch SS working arch wire in a 0.022 x 0.028-inch bracket slot
- An ANB angle between 1 and 5 degrees.
The authors used a 3D surface laser scanner to access the results. They found no statistically significant difference in the final inclination of the teeth between the patients treated using MBT and Roth bracket prescriptions. They also pointed out that their results were in agreement with the findings of an another study that investigated the same issue.
Importantly, in their discussion the authors state the following:
“It is possible that if the patients had been treated with a full-sized 0.021 x 0.025-inch SS or TMA arch wire with a greater potential for full torque expression, differences between the two bracket prescriptions could have been detected, however, we wanted this study to be a real-world study, where we treated our patients as we routinely do in the clinic.”
So, what prescription to use?
I use exclusively 0.022 MBT. At some point in my career I decided that I am not interested in more experiments with prescription and I am fine with having the one most commonly used. It is really handy that the majority of the manufacturers produce MBT brackets and it is never a problem to order them almost 24/7 even in Russia.
I saw some benefits in having slightly greater torque on the upper incisors, but was really surprised to know that no real difference is present even with 0.019 x 0.025 SS wires. Honestly, there had been a very little number of patients whom I treated up to full-size wires before I read this study and even now I do so only if the full torque expression is critical.
I think a take-away message of this study is that the differences between the prescriptions are minute. We should not expect them to be seen if we don’t treat to the full-size wires.