Surface Modifications of Dental Implants: Methods, Coatings and Biological Performance: A Critical Narrative Review

Abstract

Surface engineering is central to contemporary dental implant design because the first biological events after implantation occur at an engineered interface rather than on bulk titanium alone. Yet the clinical meaning of increasingly complex micro-, nano-, chemical and biofunctional modifications remains difficult to judge: experimental studies commonly show altered protein adsorption, cell behaviour, bone-to-implant contact or antimicrobial activity, whereas long-term clinical superiority is less consistently demonstrated. This critical narrative review examines established and emerging surface-modification methods for endosseous dental implants, with emphasis on titanium and titanium-based systems, and evaluates how topography, surface chemistry, wettability and coatings influence osseointegration, soft-tissue integration, biofilm behaviour and clinically relevant outcomes. Literature was identified through multidisciplinary biomedical and scholarly sources, complemented by citation searching, for the period 1990 to 28 June 2026, with earlier seminal work retained where necessary. The evidence supports a robust role for moderately rough microtopographies in accelerating bone apposition compared with machined surfaces, while hydrophilic chemical modifications appear to exert their clearest effects during early healing rather than consistently improving long-term survival. Calcium-phosphate and hydroxyapatite coatings are biologically attractive but remain sensitive to coating thickness, crystallinity, adhesion and dissolution. Biomolecular, drug-releasing, antimicrobial and nanostructured coatings broaden the design space, but most remain constrained by preclinical evidence, manufacturing variability, ageing, sterilisation effects and uncertain durability. A recurring translational tension is that surfaces favourable to bone integration may also increase plaque retention when exposed, making implant design a zone-specific rather than a single-property optimisation problem. Current evidence therefore favours well-characterised, reproducible surface systems with demonstrated clinical performance over escalating surface complexity itself. Future progress requires standardised surface metrology, head-to-head trials using patient-centred and peri-implant outcomes, clinically realistic biofilm models, durability testing and integrated designs that support bone, soft tissue and infection control without sacrificing retrievability or decontaminability.