Systematic Review of Experimental Gingivitis Induction Methods: Methodological Variations and Their Impact on...

Area of Science:

• Periodontology
• Oral immunology
• Translational dentistry

Background:

• Experimental gingivitis (EG) is a widely used model to study acute, reversible gingival inflammation.
• Understanding methodological variations is crucial for interpreting EG study outcomes.
• Inter-individual variability in inflammatory responses necessitates careful consideration of participant characteristics.

Purpose of the Study:

• To systematically review methodological variations in human experimental gingivitis studies.
• To evaluate outcome patterns related to clinical, molecular, and immunologic markers of gingival inflammation.
• To assess the influence of induction duration, plaque control, and participant characteristics on EG outcomes.

Main Methods:

• Systematic review of clinical trials and interventional studies on experimental gingivitis.
• Inclusion criteria: human participants, EG induction via hygiene cessation or plaque accumulation, reporting clinical or biomarker outcomes.
• Data synthesis: narrative due to heterogeneity; risk of bias and quality assessment performed.

Main Results:

• Ten studies were included, with induction durations ranging from 9 to 28 days.
• Clinical indicators of gingival inflammation consistently increased, with varying magnitudes based on methodology and participant profiles.
• Identified "fast," "slow," and "low" responder phenotypes, highlighting inter-individual variability.
• Pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and transcriptomic shifts were observed during inflammation, reversing upon recovery.

Conclusions:

• Experimental gingivitis models effectively induce acute, reversible inflammation.
• Methodological heterogeneity and lack of standardized protocols hinder direct cross-study comparisons.
• Future research requires standardized protocols and stratified analyses for refined causal insights and clinical translation.