The Oral Microbiome in Health and Disease: Microbial Ecology, Dysbiosis, and Clinical Implications for Dental Practice

<jats:p>The oral cavity harbors one of the most complex microbial ecosystems in the human body, comprising more than 700 bacterial species alongside fungi, viruses, and archaea. This review provides a comprehensive examination of the composition, ecological dynamics, and clinical significance of the oral microbiome, with particular emphasis on implications for dental practice. We describe site-specific microbial communities and biofilm succession, analyze the role of keystone pathogens in driving dental caries, gingivitis, periodontitis, peri-implantitis, and oral candidiasis, and examine the Socransky periodontal complex classification system. The bidirectional oral-systemic disease axis is explored, linking periodontal dysbiosis to cardiovascular disease, type 2 diabetes, colorectal cancer, Alzheimer's disease, and adverse pregnancy outcomes. A four-step evidence-based clinical management framework integrating diagnostic risk assessment, mechanical debridement, targeted antimicrobial and biological adjuncts, and long-term preventive maintenance is presented. Microbiome-based diagnostics and emerging precision dentistry approaches are also discussed. Understanding oral microbial ecology is indispensable for contemporary, evidence-based dental practice. </jats:p>