Skeletal and dental changes induced by the Flip-Lock Herbst appliance in the treatment of Angle's class II division 1 malocclusion during active growth period: A preliminary study.

Sridhar Premkumar,Sushmitha R Iyer,Mangaleswari Muruganandam

doi:10.34172/joddd.2021.011

Abstract

Background. The Flip-Lock Herbst (TP Orthodontics Inc.) is a fixed functional appliance, a variant of the Herbst appliance, introduced by Miller. It is claimed to have better patient tolerance due to its increased freedom for the mandible’s lateral movements. There have been no studies on the flip lock Herbst till date. This study was undertaken to assess the efficiency of the Flip-Lock Herbst appliance in correcting Angle’s class II division 1 malocclusion. Methods. Eight subjects in their active growth period with class II division 1 malocclusion due to a retrognathic mandible were included in the study. Standardized lateral cephalometric radiographs were used to evaluate skeletal and dental changes with the SO analysis. Paired samples t-test was used to assess statistical significance. Results. Statistically significant increases in mandibular length (pg/OLp) and effective mandibular length (ar/OLp + pg/OLp) were observed. There was a significant maxillary restraining effect. Dental effects were significant and exhibited class II correction features except for the position of lower incisors within the mandible (ii/OLp - pg/OLp). Skeletal changes accounted for 61% and dental changes for 39% of the total treatment for molar correction. For overjet correction, skeletal changes contributed to 63% and dental changes to 37% of the total treatment. Conclusion. The Flip-Lock Herbst appliance was efficient in correcting Angle’s class II division 1 malocclusion due to a retrognathic mandible. Both skeletal and dental changes were evident, with the former predominating (60:40).

Highlights

Growth modification is typically carried out during the adolescent period, which is already rife with many social and developmental changes
The success of any treatment depends on patient compliance, which is difficult to predict and, to some extent, depends on the degree of discomfort and treatment duration.[1]
Patient perception of treatment is an important factor, and this varies among the three types of Fixed functional appliances (FFAs): rigid, semi-rigid, and flexible.[5,6]

Summary

Introduction

Growth modification is typically carried out during the adolescent period, which is already rife with many social and developmental changes. The success of any treatment depends on patient compliance, which is difficult to predict and, to some extent, depends on the degree of discomfort and treatment duration.[1] Fixed functional appliances (FFAs) place the onus of treatment on the orthodontist and have the advantage of being compliancefree. Since they jump the bite continuously, they act full time and shorten treatment duration.[2,3,4] Patient perception of treatment is an important factor, and this varies among the three types of FFAs: rigid, semi-rigid, and flexible.[5,6] The Herbst appliance, introduced by Dr. The Flip-Lock Herbst (TP Orthodontics Inc.) is a fixed functional appliance, a variant of the Herbst appliance, introduced by Miller. This study was undertaken to assess the efficiency of the Flip-Lock Herbst appliance in correcting Angle’s class II division 1 malocclusion

Methods

Results

Discussion

Conclusion