Letters From Our Readers

To: Editor, The Angle Orthodontist

Re: Anchorage condition during canine retraction using transpalatal arch with continuous and segmented arch mechanics. The Angle Orthodontist. 2016;86:380–385.

I found this paper to be very interesting. However, I wonder if you could explain why the T-loop was designed to have the loop positioned off-center to the mesial, rather than to the distal? Placing the loop mesially would increase the alpha moment and thus enhance anchorage of the anterior segment, which was not the desired intent.

Also, the study compared T-loop mechanics to continuous wire space closure using sliding mechanics. Can you comment on whether you think friction of the continuous wire played any role in the differences you saw between the two outcomes? If the beta bend placed in the T-loop was meant to preserve anchorage in the T-loop group, were there any steps taken to conserve anchorage in the continuous wire patients? Perhaps a better comparison would have been accomplished using only patients treated with T-loops but between those with and those without posterior anchorage bends.

Thank you for publishing this interesting paper.

Surbhi Thakkar

Harpreet Singh

Delhi, India