Adjunctive Therapies in Periodontitis: Current Concepts and the Future.

Periodontitis is a chronic, host-mediated inflammatory disease in which microbial dysbiosis and dysregulated immune responses drive the destruction of tooth-supporting tissues. Although conventional therapy remains centered on mechanical biofilm control, persistent inflammation and alveolar bone loss in susceptible individuals underscore the need for adjunctive strategies. Translating preclinical discoveries into predictable clinical outcomes, however, remains a major challenge in periodontal research. This narrative review integrates two interrelated themes, translational research methodology and adjunctive therapeutic innovation, to critically examine how preclinical findings can be more effectively bridged to clinical practice in periodontitis management. Evidence was synthesized from experimental, translational, and clinical studies retrieved from PubMed, Scopus, and Web of Science up to September 2025. Emphasis was placed on mechanistic insights, model validity, and translational feasibility across host-modulatory, natural, probiotic, and device-based adjuncts. Animal models remain indispensable for mechanistic understanding and therapeutic testing but face biological and methodological limitations that hinder direct extrapolation to humans. Interspecies differences, short disease kinetics, and non-standardized endpoints constrain translational predictability. Addressing these gaps requires refined modeling, standardized outcomes, and integration of systemic risk factors. Within this methodological framework, several adjunctive modalities, including specialized pro-resolving mediators, probiotics, natural compounds such as curcumin and resveratrol, and device-based therapies like antimicrobial photodynamic therapy demonstrate promising anti-inflammatory, osteoimmunomodulatory, and regenerative effects. Emerging translational tools such as bioresponsive drug delivery systems, nanocarriers, 3D-printed scaffolds, and AI-driven precision periodontics may further enhance clinical relevance and patient-specific targeting. Advancing adjunctive periodontal therapy demands harmonized translational models, bioresponsive delivery platforms, and precision diagnostic tools that bridge preclinical efficacy with real-world outcomes. By aligning methodological rigor with therapeutic innovation, translational research can accelerate the safe and effective clinical integration of next-generation adjunctive treatments in periodontitis.