Aim: The aim of this study was to compare dentoskeletal effects and patient’s satisfaction with a modified twin-block (clear twin-block) and classic twin-block.

Materials and methods: A total of 62 patients with skeletal class II malocclusion contributing to mandibular retrognathism with a minimum of 4 mm overjet, the FMA angle between 20 to 25 degree and being in stage 2 to 3 of cervical vertebral maturation participated in this study. Subjects were randomized in 1:1 ratio to classic and clear twin-block. Lateral cephalograms were taken at two stages—Pre- and post-treatment (when the overjet reduced to 1 to 0 mm). All the measurements were done with Dolphin software version 10.5. Four months after the start of the treatment the patients were asked to fill the questioners regarding their compliance from the appliances.

Results: Both classic and clear twin -block groups showed mandibular advancement without statistically significant difference between them. However, SNB angle increased slightly more in clear group than the classic one.’’ Headgear effect’’ is not statistically noticeable in both groups. However, SNA angle decreased slightly more in Classic group. Increased in lower incisors proclination was happening in both groups, but in a clear group, this increase was significantly less. Overbite reduction could be seen in both groups with significantly more reduction in the classic group.

Conclusion: Increase in lower incisors proclination was less in clear group than the classic one. Overbite reduction was more in the classic group than the classic one.

Clinical significance: Clear twin-block is more beneficial in skeletal class II patients with proclined lower incisors and vertical growth pattern.

Keywords: Appliance, Functional orthodontic, Twin-block

Trial registration: Iranian research clinical trial, Agreement NO.2014040817180N1

How to cite this article: Golfeshan F, Soltani MK, Zohrei A, Poorolajal J. Comparison between Classic Twin-block and a Modified Clear Twin-block in Class II, Division 1 Malocclusions: A Randomized Clinical Trial. J Contemp Dent Pract 2018;19(12):1456-1463.

Source of support: Nil

Conflict of interest: Trial registration: Iranian research clinical trial, agreement No.2014040817180N1