# Evaluation of the Salivary Expression of Type I Collagen, Osteocalcin, and Osteonectin in Patients Treated With Myofunctional Therapy: A Clinical Study

## TL;DR

This study shows that using a Twin Block appliance in adolescents with a specific jaw misalignment increases salivary biomarkers linked to bone growth and remodeling.

## Contribution

The study demonstrates the non-invasive use of salivary biomarkers to monitor bone adaptation during myofunctional therapy.

## Key findings

- Salivary levels of collagen type I, osteocalcin, and osteonectin increased significantly 30 days after appliance insertion.
- Biomarker levels remained elevated at 60 days, indicating ongoing bone adaptation.
- Saliva can serve as a non-invasive tool to assess treatment-induced bone changes in orthodontic therapy.

## Abstract

Introduction

Skeletal Class II malocclusion, commonly resulting from mandibular retrognathism, poses both functional and aesthetic challenges in growing patients. Functional orthopaedic appliances, such as the Twin Block, aim to correct this by stimulating mandibular growth through forward positioning. This biomechanical stimulus is believed to trigger adaptive remodelling at the condylar cartilage level, influencing bone formation pathways and playing a crucial role in the release of salivary biomarkers such as osteocalcin, osteonectin, and collagen type 1, which can be non-invasively detected.

Aim

This study aims to assess the salivary levels of collagen type I, osteocalcin, and osteonectin in skeletal Class II patients undergoing myofunctional therapy with a Twin Block appliance.

Methods

A total of 10 adolescents aged 8-15 years with skeletal Class II malocclusion were selected and treated with Twin Block appliances. Unstimulated saliva samples were collected at four time points: baseline (prior to appliance insertion) and 15, 30, and 60 days post-insertion. Samples were stored at -82°C and analysed for type I collagen, osteocalcin, and osteonectin using biochemical assays.

Results

All three biomarkers (collagen type I, osteocalcin, and osteonectin) showed a consistent pattern of expression. Levels increased from baseline and peaked at 30 days, indicating heightened osteogenic activity and extracellular matrix remodelling. By 60 days, a slight decline was observed; however, levels remained significantly elevated compared to baseline, suggesting continued bone adaptation in response to functional stimulation.

Conclusion

Myofunctional therapy with a Twin Block appliance elicits a measurable biological response indicative of bone remodelling in adolescents with skeletal Class II malocclusion. The increase in salivary levels of key osteogenic markers validates the efficacy of functional appliance therapy and highlights the utility of saliva as a non-invasive diagnostic tool for monitoring treatment-induced bone changes.