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Updated: Jan 17, 2026
Oral Biofilm Analysis of Palatal Expanders by Fluorescence In-Situ Hybridization and Confocal Laser Scanning Microscopy
Published on: October 20, 2011
Time-stratified microbial colonization in passive self-ligating, active self-ligating, and conventional brackets: A
Gowri Sankar Singaraju1, Shibitha Balakrishnan2, Harneet Kaur3
1Department of Orthodontics, Narayana Dental College, Nellore, Andhra Pradesh, India.
Background:
Fixed orthodontic appliances can increase microbial colonization and periodontal inflammation. Bracket design-particularly the presence or absence of elastomeric ligatures-may influence this risk.
Objectives:
To compare microbial and periodontal outcomes among passive self-ligating brackets, active self-ligating brackets, and conventional brackets during orthodontic treatment.
Materials And Methods:
A systematic search of PubMed, Scopus, Google Scholar, Cochrane Library, and ScienceDirect was conducted up to 24th August 2024 following a predefined PICOS strategy. Risk of bias was assessed using RoB 2.0 and ROBINS-I tools. Meta-analyses were performed for time-stratified microbial counts (Streptococcus mutans, Lactobacillus) and periodontal parameters (plaque index [PI], gingival index [GI], probing pocket depth [PPD]) using RevMan 5.0. Evidence quality was assessed via GRADE and Swedish Agency for Health Technology Assessment (SBU) criteria.
Results:
Fifteen studies contributed data to the systematic review, of which six were included in the meta-analysis (751 patients, 1227 brackets) across different microbial and periodontal parameters. Passive Metal Self-Ligating Brackets (PMSLB) demonstrated modest but consistent microbial benefits over Conventional Metal Brackets (CMB), especially at 0-3 months (MD = -0.50; 95% CI: -1.04 to -0.04; low-certainty). Reductions in Lactobacillus and other microbes were observed but not statistically significant (moderate certainty). Active Metal Self-Ligating Brackets (AMSLB) showed intermediate outcomes (low certainty). Periodontal improvements were noted in select studies but lacked consistency and had high heterogeneity (very low certainty).
Conclusion:
PMSLB offer modest microbial advantages over CMB in early treatment phases. AMSLB performed better than CMB but were less consistent than PMSLB. Due to limited evidence, further well-designed RCTs are required.
