# A Comparative Mixed Longitudinal Evaluation of Doxycycline Solution as an Aligner Rinse Compared With Conventional Mouthwashes on Microbial, Esthetic, and Inflammatory Outcomes During Orthodontic Tooth Movement

## TL;DR

This study compares doxycycline and chlorhexidine as aligner rinses, finding doxycycline more effective in reducing bacteria, improving aligner clarity, and boosting biological markers during orthodontic treatment.

## Contribution

The study introduces doxycycline as a novel, dual-action aligner rinse with antimicrobial and anti-inflammatory benefits.

## Key findings

- Doxycycline reduced plaque, gingival inflammation, and microbial counts more effectively than chlorhexidine.
- Doxycycline-treated aligners maintained better clarity and increased alkaline phosphatase levels.
- A strong inverse correlation was found between alkaline phosphatase and microbial counts or inflammation.

## Abstract

Introduction: Clear aligners are vulnerable to microbial colonization, discoloration, and inflammation-associated delays in orthodontic tooth movement. This study explores the use of sub-antimicrobial-dose doxycycline as a novel aligner disinfectant, owing to its combined antimicrobial, anti-inflammatory, and osteogenic effects.

Objective: This study aims to compare the clinical, microbiological, and biological efficacy of 0.1% doxycycline solution versus 0.2% chlorhexidine gluconate in aligner therapy.

Materials and methods: A mixed longitudinal cohort design was employed, enrolling 60 patients undergoing aligner therapy. Participants received alternating aligners soaked in doxycycline (group A) and chlorhexidine (group B). Clinical indices, colony-forming units (CFUs), gingival crevicular fluid (GCF) alkaline phosphatase (ALP), and aligner transparency were evaluated at baseline, two weeks, one month, three months, and six months. Random allocation was performed using a computer-generated sequence. Outcome assessors were blinded. Microbial cultures, ALP assays, and spectrophotometric evaluations were conducted using standardized protocols.

Results: Group A exhibited significantly lower plaque and gingival indices, reduced CFUs, enhanced aligner clarity, and elevated ALP levels compared to group B (p < 0.01). Pearson’s correlation showed a strong inverse relationship between ALP and both CFUs and the gingival index.

Conclusions: Doxycycline demonstrated superior microbial control, esthetic maintenance, and biological stimulation, supporting its potential role as a dual-action adjunct in aligner-based orthodontics. Further multicenter studies are recommended to validate these findings.