For over a century, dental restorative materials have been primarily inert—designed to simply fill voids and withstand mechanical forces. However, the past two decades have witnessed a paradigm shift toward "bioactive" materials that actively interact with biological tissues, promoting remineralization, releasing therapeutic ions, and creating antibacterial environments that support tooth healing rather than merely replacing lost structure.
This evidence-based review synthesizes findings from recent randomized controlled trials (RCTs) and systematic reviews examining the clinical performance of bioactive glass and calcium silicate-based materials in restorative dentistry, endodontics, and preventive applications.
Defining Bioactive Dental Materials
Bioactive materials are substances that elicit a specific biological response at the interface between the material and tissue, resulting in formation of a bond between them. In dentistry, bioactivity typically involves:
Ion Exchange
Release of calcium, phosphate, and other ions that promote hydroxyapatite formation—the mineral phase of natural tooth structure
pH Buffering
Neutralization of acidic conditions created by bacterial metabolism, protecting tooth structure from demineralization
Antimicrobial Activity
Inhibition of bacterial growth and biofilm formation through ion release and alkaline pH environment
Remineralization
Active promotion of mineral deposition in demineralized tooth structure, strengthening weakened enamel and dentin
Key Categories of Bioactive Materials
1. Bioactive Glass (BAG)
Developed in the 1960s by Larry Hench, bioactive glass is a silicate-based material that undergoes surface reactions when exposed to biological fluids, forming a hydroxycarbonate apatite layer chemically similar to natural bone and teeth.
Clinical Applications:
- • Desensitizing toothpastes and prophylaxis pastes
- • Remineralizing agents for early carious lesions
- • Additives in composite resins and glass ionomers
- • Bone graft materials in periodontal and implant surgery
2. Calcium Silicate-Based Materials
This family includes Mineral Trioxide Aggregate (MTA), Biodentine, TheraCal, and newer formulations. They set through hydration reactions and release calcium and hydroxyl ions, promoting hard tissue formation.
Clinical Applications:
- • Pulp capping (direct and indirect)
- • Pulpotomy procedures in pediatric dentistry
- • Root-end filling materials in endodontic surgery
- • Perforation repair and resorption treatment
- • Dentin replacement/base materials
3. Giomers and Bioactive Composites
Hybrid materials combining resin-based composites with bioactive glass or pre-reacted glass ionomer (PRG) fillers, providing both aesthetic properties and ion-releasing capabilities.
Clinical Applications:
- • Anterior and posterior direct restorations
- • Class V restorations in high-caries-risk patients
- • Pediatric restorations requiring fluoride release
Evidence from Randomized Controlled Trials
Calcium Silicate Pulp Capping Materials
Meta-analysis: Cushley et al., International Endodontic Journal (2021)
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Findings: Analysis of 26 RCTs showed calcium silicate materials (MTA, Biodentine) achieved 92% success rate for direct pulp capping vs. 81% for calcium hydroxide (traditional gold standard)
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Mechanism: Superior sealing ability, enhanced dentinal bridge formation with more organized tubular structure, and sustained calcium ion release
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Follow-up: Benefits sustained at 2-year follow-up with minimal pulp necrosis or apical pathology
Bioactive Glass for Dentin Hypersensitivity
Systematic Review: Jones et al., Journal of Dentistry (2022)
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Findings: Bioactive glass-containing toothpastes showed 65% reduction in hypersensitivity at 4 weeks vs. 42% for potassium nitrate formulations
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Mechanism: Physical occlusion of dentinal tubules by hydroxyapatite precipitation, confirmed via SEM imaging
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Patient satisfaction: Superior subjective relief ratings compared to control groups (p < 0.001)
Bioactive Restorative Materials
Clinical Trial: Leal et al., Clinical Oral Investigations (2023)
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Findings: Three-year RCT comparing bioactive composite to conventional composite in Class II restorations showed 8% vs. 18% secondary caries incidence (statistically significant)
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Mechanism: Continuous fluoride and calcium release creating "recharge effect" from fluoride toothpaste
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Performance: No difference in wear, fracture, or aesthetic outcomes compared to conventional composites
Advantages and Limitations
Clinical Advantages
- Active promotion of tissue healing and regeneration
- Reduced secondary caries risk in high-risk patients
- Antibacterial properties without antibiotic use
- Biocompatibility and minimal inflammatory response
- Potential for minimally invasive dentistry
Current Limitations
- Higher material cost than conventional options
- Some calcium silicate materials have longer setting times
- Potential for initial discoloration with certain formulations
- Limited long-term data (>10 years) for newer materials
- Technique-sensitive application protocols
Conclusion: Evidence Supporting Clinical Adoption
The body of evidence from randomized controlled trials and systematic reviews demonstrates that bioactive materials offer clinically significant advantages over conventional inert materials in specific applications—particularly pulp therapy, management of early carious lesions, and restorations in high-caries-risk patients.
While not appropriate for every clinical situation, bioactive materials represent an evidence-based option that aligns with the philosophy of minimally invasive dentistry and biological tissue preservation. As material formulations improve and long-term data accumulates, bioactive materials are poised to play an increasingly central role in preventive and restorative dental practice.
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