Comparison between Classic Twin-block and a Modified Clear Twin-block in Class II, Division 1 Malocclusions: A Randomized Clinical Trial

Abstract

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

Myobrace versus twin block in the treatment of class II malocclusion in Children: A systematic review

“…( Lin et al, 2019 , Zhang et al, 2020 ) Children with a considerable overjet and class II malocclusion benefit the most from it, even at an early stage of development, as functional devices like twin blocks can be utilized. ( Chen et al, 2022 , Golfeshan et al, 2018 , DiBiase and Qureshi, 2020 ) Ajami S et al stated that twin blocks have the potential to impact the class II malocclusion patients' facial aesthetics by causing modifications to the skeletal and dentoalveolar structures. ( Fekonja, 2022 ).…”

Modified Essix Twin Block Appliance: Successful Application in Adult Patient- A Case Report

“…Overbite reduction could be seen in both groups with significantly more reduction in the classic group. 2 Tooth movements are slower in older patients, and the skeletal response diminishes as patients age increases. Adults respond with limited skeletal adaptation.…”

“…Significant proclination of lower incisors had been consistently reported as a major side effect of Twinblock appliances. 2 This complication, generally acknowledged for functional appliances, is attributed to a protrusive effect on the lower incisors exerted by the lingual appliance components while the mandible attempts to rebound to normal resting posture. 3 Various designs and modifications of twin-block appliances have been used to decrease this side effect.…”

Efficacy of a modified twin block appliance compared with the traditional twin block appliance in children with hyperdivergent mandibular retrognathia: protocol for a single-centre, single-blind, randomised controlled trial

“… 33 However, this study did not involve a significant sagittal discrepancy between the maxilla and the mandible. A review of the literature found that studies on modified functional appliances were limited to patients with normal growth patterns, 34 35 and there was a lack of systematic high-quality studies on children of long-face growth patterns.…”