Dentoskeletal Effects Produced by Twin Block Appliance And Its Modifications In Randomized Control Trials In Children Aged 10-14 Years: A Systematic Review

Abstract

Background: Malocclusions are multifactorial in origin and primarily associated with genetic and environmental factors. Several systems have been employed to classify malocclusions, the most accepted being Angle’s classification. It includes three classes, of which class II is crucial to the current review. According to Angle, Class II malocclusion represents the distal relationship of the mandible with maxilla. Class II malocclusion is characterized by retrognathic mandible, a prognathic maxilla or a combination of both. Various appliances can rectify this malocclusion, one of which is twin block appliance. The twin block appliance consists of maxillary and mandibular acrylic plates with bite blocks that posture the mandible forward on closure and is indicated for the correction of Class II
malocclusions.This appliance has been adapted in conventional and modified versions to produce effective results.
Objectives: This review was done to inspect the dentoskeletal effects produced by twin block appliance and its modifications in randomized control trials in children aged 10-14 years
Methods: A literature search was conducted using PubMed, Scopus, Clarivate Analytics' Web of Science and Cochrane databases. Eligibility criteria followed the PICO questions. This review planned to include “randomized controlled trials” with cross-over designs or parallel-group. Participants in this review are children who have no systemic condition and are aged from 10-14 years with clinical diagnosis of Angles class II division I malocclusion was included regardless of gender and race. Two independent reviewers (AP, VP) performed study selection, data extraction and appraisal. It was presented it in “characteristics of studies table” and disagreements of primary reviewers were resolved by a third reviewer (SP) The risk of bias was assessed by the revised Cochrane risk-of-bias tool for randomized trials and discrepancies in risk of bias assessment were resolved by fourth reviewer (ATP).
Results: Three randomized clinical trials (RCTs) were included in the review. All studies fulfilled the PICO criteria. There were no significant differences in the reported outcomes between investigated treatments in all included RCTs. All of the included studies reported the most critical outcome being correction of class II, division 1 malocclusion. Patients of all the included studies showed good compliance.
Conclusions: The systematic review sheds light on the dentoskeletal effects produced by twin block appliance and its modifications. The review brings us to the conclusion that the twin block appliance has great potential for producing profound dentoskeletal changes in children aged 10-14 years. The review also discusses the modifications of twin block appliance which show good potential to bring about desired dentoskeletal effects. It is also interesting to notice that certain components such as the labial bow may be omitted and addition of components such as southend clasps and torqueing springs may provide better control over incisor movement as well as movement of associated skeletal counterparts. Hence it is prudent to incorporate the modifications of this in appropriate clinical scenarios.