Emerging Trends in Restorative Dental Materials: Review Article

Introduction

Restorative dentistry constitutes a central component of contemporary oral healthcare, aiming not only to restore the form and function of teeth compromised by caries, trauma, or wear, but also to preserve the long-term biological integrity of the dentition and surrounding tissues. Conventional restorative materials—including dental amalgam, resin-based composites, and glass ionomer cements—have enabled decades of clinical success; however, their limitations remain clinically significant. Issues such as material degradation, marginal leakage, secondary caries, and suboptimal biocompatibility continue to contribute to restoration failure and replacement, representing a substantial burden for patients and healthcare systems alike (Fernandes et al., 2023; Liang et al., 2023; Paradowska-Stolarz et al., 2023; Sequeira et al., 2023; Chopra et al., 2024; Li et al., 2024).

Over the past decade, restorative dentistry has undergone a conceptual shift from passive replacement of lost tooth structure toward biologically informed and functionally active material systems. This transition reflects growing recognition that restorative materials exist within a complex oral environment characterized by dynamic mechanical loading, fluctuating pH, microbial challenge, and continuous interaction with dental hard tissues and saliva. Consequently, contemporary material development increasingly emphasizes bioactivity, multifunctionality, and environmental responsiveness, with the goal of enhancing tissue integration, supporting remineralization, and mitigating the etiological factors underlying restoration failure—particularly recurrent caries and interfacial degradation (Atia et al., 2023; Fernandes et al., 2023; Liang et al., 2023; Paradowska-Stolarz et al., 2023; Xie et al., 2023; Chopra et al., 2024).

Historically, the introduction of resin composite materials in the mid-twentieth century marked a milestone in aesthetic and adhesive dentistry. Since then, incremental advances have improved mechanical performance and handling characteristics; however, recent research has expanded beyond incremental optimization toward fundamentally new material paradigms. Bioactive restorative materials capable of releasing therapeutic ions—such as fluoride, calcium, and phosphate—have been developed to promote dentin remineralization and modulate the cariogenic environment. These approaches align with contemporary preventive dentistry principles and have been increasingly recognized in professional guidelines and consensus statements (Christie et al., 2023; Flores-Espinoza et al., 2023; Liang et al., 2023; Moharil et al., 2023; Woźniak-Budych et al., 2023).

Parallel advances in nanotechnology have further transformed restorative material design. The incorporation of nanoscale fillers and functional nanoparticles has been shown to enhance mechanical strength, wear resistance, esthetics, and antimicrobial activity, while maintaining favorable handling properties. Such nanostructured systems also enable more precise control over material–tissue and material–biofilm interactions, offering new strategies to address bacterial colonization and biofilm-associated degradation at restoration margins (Aydın et al., 2023; Gallicchio et al., 2023; Unnadkat et al., 2023; Atta et al., 2024; Rues et al., 2024; Uyumaz et al., 2024).

Digital technologies have likewise reshaped restorative workflows. Additive manufacturing techniques, particularly three-dimensional printing, now permit the fabrication of customized restorations with high geometric accuracy, reduced material waste, and improved reproducibility. These technologies support minimally invasive treatment planning and align with broader trends toward digital dentistry and personalized care (Alsaeed, 2022; Fronza et al., 2022; Kodaira et al., 2022). In parallel, the emergence of so-called “smart” restorative materials—designed to respond to environmental cues such as pH changes or mechanical stress—represents an effort to develop restorations that actively adapt to cariogenic challenges rather than merely withstand them (Aydın et al., 2023; Unnadkat et al., 2023; Ortega et al., 2024).

Sustainability has also become an increasingly relevant consideration in dental material science. Environmental concerns related to material toxicity, waste generation, and lifecycle impact have prompted exploration of biodegradable components, mercury-free alternatives, and manufacturing processes with reduced ecological footprints. These developments reflect a growing intersection between clinical performance, public health priorities, and environmental responsibility within dentistry (Alsaeed, 2022).

Finally, progress in adhesive dentistry has resulted in the development of universal adhesive systems that aim to simplify clinical protocols while maintaining reliable bonding across diverse substrates. Such systems address technique sensitivity and may contribute to improved restoration longevity when appropriately applied (Colak & Katirci, 2023; Lekhwani et al., 2023; Rues et al., 2024). Figure 1 summarizes the major emerging classes of restorative dental materials and their primary biological, functional, and clinical contributions.

Against this background, the present review synthesizes recent literature to provide a structured overview of evolving trends in restorative dental materials, with particular emphasis on bioactive, nanostructured, digitally manufactured, smart, and sustainable systems. By critically examining their clinical applications, advantages, and current limitations, this review seeks to inform evidence-based material selection and highlight future directions for research and clinical practice in restorative dentistry.

Bioactive and ion-releasing materials

Bioactive and ion-releasing restorative materials represent a significant conceptual departure from traditional inert filling materials, reflecting a broader shift in restorative dentistry toward biologically interactive treatment strategies. Rather than functioning solely as space-filling substitutes for lost tooth structure, these materials are designed to engage dynamically with the surrounding dental tissues and oral environment, with the aim of supporting remineralization, enhancing interfacial stability, and reducing susceptibility to recurrent disease (Li et al., 2024). This paradigm is particularly relevant given that secondary caries and interfacial breakdown remain leading causes of restoration failure despite advances in adhesive techniques (Fernandes et al., 2023; Liang et al., 2023; Paradowska-Stolarz et al., 2023).

A defining characteristic of bioactive restorative systems is their capacity to release therapeutically relevant ions, most commonly fluoride, calcium, and phosphate. These ions contribute to the remineralization of demineralized enamel and dentin, buffer local acidity, and may alter the ecological balance of dental biofilms in a manner that is less conducive to cariogenic activity (Fernandes et al., 2023; Liang et al., 2023). Increasing experimental and clinical evidence suggests that such ion-mediated effects are especially beneficial in patients with elevated caries risk, where conventional restorative approaches may be insufficient to counteract ongoing pathological challenges (Paradowska-Stolarz et al., 2023; Chopra et al., 2024).

Glass ionomer cements (GICs) and resin-modified glass ionomer cements remain foundational examples of clinically established bioactive materials. Their ability to chemically bond to tooth structure, coupled with sustained fluoride release, has supported their widespread use in minimally invasive and preventive restorative strategies (Moharil et al., 2023; Xie et al., 2023). More recently, research has focused on enhancing the bioactivity of resin-based systems through the incorporation of bioactive glass fillers produced via sol–gel or melt-derived processes. These fillers have demonstrated the capacity to release calcium and phosphate ions and to promote apatite formation at the tooth–material interface, suggesting potential benefits for dentin repair and interfacial stability (Xie et al., 2023).

Clinical evidence indicates that restorations incorporating bioactive components can achieve retention and survival rates comparable to conventional resin composites when used in appropriate indications. Moreover, comparative analyses and controlled clinical studies suggest a reduced incidence of secondary caries associated with certain bioactive materials, particularly in populations with high caries activity or compromised oral conditions (Paradowska-Stolarz et al., 2023; Sequeira et al., 2023). While such findings are encouraging, authors consistently emphasize the importance of patient selection, lesion location, and material-specific properties when interpreting clinical outcomes.

Beyond restorative fillings, bioactive and ion-releasing materials have gained particular prominence in vital pulp therapy. Calcium-releasing composites, hydraulic calcium silicate cements, and bioactive liners have been increasingly investigated for applications such as direct and indirect pulp capping. Evidence from systematic reviews indicates favorable outcomes in terms of dentin bridge formation and pulp vitality preservation, with reported success rates that compare favorably to traditional materials when strict clinical protocols are followed (Carneiro et al., 2023; Li et al., 2023; Urkande et al., 2023; Ziaei et al., 2024). The biological activity of these materials is often attributed to their alkaline pH, ion release, and capacity to stimulate odontoblastic differentiation and reparative dentinogenesis. Materials incorporating hydroxyapatite, calcium silicates, and related bioceramics further support tissue integration through chemical and structural similarity to natural hard tissues (Frąckiewicz et al., 2023).

Despite their advantages, bioactive restorative materials are not without limitations. Concerns persist regarding mechanical strength, wear resistance, and long-term durability, particularly in high-load posterior applications. As a result, hybrid material systems that combine bioactive fillers with reinforced resin matrices have been developed to balance biological functionality with mechanical performance (Fernandes et al., 2023; Flores-Espinoza et al., 2023). Ongoing research also highlights the need for clearer and more standardized definitions of “bioactivity” in dentistry, as variability in testing methods and outcome measures complicates comparisons across studies and may obscure clinically meaningful distinctions between materials (Liang et al., 2023). Table 1 compares major classes of emerging restorative dental materials, highlighting their functional mechanisms, clinical advantages, and current limitations.

Table 1. Emerging Restorative Dental Materials: Mechanisms, Benefits, and Limitations

Future developments in this field are increasingly focused on multifunctional designs that integrate bioactivity with additional protective mechanisms, such as antimicrobial or antibiofilm properties. By addressing both biological repair and microbial challenge, next-generation restorative materials aim to provide more comprehensive protection against restoration failure while aligning with minimally invasive and preventive care principles (Agrawal et al., 2023; Li et al., 2024).

Nanomaterials in restorative dentistry

Nanotechnology has had a substantial impact on restorative dentistry by enabling the design of materials with enhanced mechanical performance, improved esthetic outcomes, and added biological functionality. The incorporation of nanoscale fillers and functional nanoparticles into restorative systems represents a strategic evolution from conventional microfilled and hybrid composites, allowing finer control over material structure and behavior at the tooth–restoration interface (Gallicchio et al., 2023; NWNA et al., 2024).

Commonly employed nanoparticles—including silica, zirconia, silver, and zinc oxide—are integrated into resin-based composites to improve flexural strength, wear resistance, and polish retention while reducing polymerization shrinkage and surface roughness (Christie et al., 2023; Uyumaz et al., 2024). Owing to their high surface area and uniform dispersion, nanofillers facilitate stronger filler–matrix interactions, which translate into improved mechanical stability under functional loading. In addition, nanoscale fillers allow higher filler loading without compromising handling characteristics, contributing to improved longevity of restorations.

Beyond mechanical enhancement, nanomaterials have enabled the development of biomimetic restorative designs that more closely replicate the hierarchical structure of natural enamel and dentin. By mimicking enamel-like prism organization and nanoscale mineralization patterns, nano-engineered composites demonstrate improved optical properties and interfacial adaptation, supporting both esthetic integration and functional performance (Chacón Gahona et al., 2023; Woźniak-Budych et al., 2023). Such biomimetic strategies align with minimally invasive dentistry principles by promoting more harmonious interactions between restorative materials and dental hard tissues.

Nanotechnology has also facilitated the incorporation of antibacterial functionality into restorative materials. Nanoparticles such as silver and zinc oxide exhibit broad-spectrum antimicrobial activity, primarily through disruption of bacterial cell membranes and interference with metabolic pathways. When embedded within restorative matrices, these particles have been shown to inhibit biofilm formation and reduce bacterial colonization at restoration margins—an effect that may contribute to lower rates of secondary caries when appropriately balanced with biocompatibility considerations (Flores-Espinoza et al., 2023; Uyumaz et al., 2024).

Clinically, nano-hybrid and nanofilled composites are now widely used for both anterior and posterior restorations. Long-term observational studies report favorable outcomes with respect to polishability, surface gloss retention, and color stability compared with earlier composite generations (Atia et al., 2023; Chopra et al., 2024). Nevertheless, concerns regarding potential cytotoxicity, nanoparticle release, and long-term biological effects have prompted careful material refinement. Contemporary formulations increasingly employ surface-treated or immobilized nanoparticles to minimize biological risk while preserving functional benefits (Frąckiewicz et al., 2023; Moharil et al., 2023).

Looking forward, nanotechnology is expected to play a key role in emerging fabrication techniques, particularly through the development of nano-enabled materials for additive manufacturing. Such approaches offer opportunities to combine nanoscale reinforcement with digital precision, potentially expanding the clinical applicability of printed restorations (Fronza et al., 2022; Kodaira et al., 2022).

Additive manufacturing and three-dimensional printed restorations

Additive manufacturing, commonly referred to as three-dimensional (3D) printing, has emerged as a transformative technology in restorative dentistry by enabling the rapid fabrication of patient-specific restorations with high geometric accuracy. Unlike subtractive milling techniques, 3D printing builds restorations layer by layer, allowing efficient material use, reduced waste, and greater design flexibility for complex clinical scenarios (Fronza et al., 2022; Loya et al., 2023; Atta, et al., 2024).

Current dental 3D printing applications primarily involve photopolymer-based resins and, to a lesser extent, ceramic-filled or hybrid materials. These materials are widely used for temporary crowns, inlays, onlays, surgical guides, and provisional prostheses. Advances in printing resolution and post-processing protocols have resulted in restorations with dimensional accuracy comparable to conventionally milled counterparts, with reported marginal discrepancies generally within clinically acceptable ranges (Kodaira et al., 2022; Atta et al., 2024).

Recent overviews highlight that 3D-printed restorations demonstrate favorable fit and reproducibility, particularly for interim applications, while offering significant reductions in fabrication time and chairside adjustments (Fronza et al., 2022). The ability to digitally design and fabricate restorations also supports streamlined workflows and enhances consistency across treatment stages, making additive manufacturing an attractive option within digital dentistry ecosystems.

Despite these advantages, limitations remain regarding the mechanical strength, wear resistance, and long-term stability of currently available printed materials, particularly for definitive posterior restorations subjected to high occlusal loads. As a result, most permanent applications continue to rely on milled ceramics or conventional composites, while research efforts focus on improving printed material formulations (Loya et al., 2023).

An emerging area of interest involves the integration of bioactive components into printable resins, aiming to combine digital fabrication with ion release and remineralization potential. Preliminary studies suggest that incorporating bioactive fillers into printable matrices may enhance biological performance without compromising printability, although further validation is required before widespread clinical adoption (Xie et al., 2023; Li et al., 2024). Future developments may also include chairside or in-office printing systems capable of delivering immediate restorations, further reducing treatment time and improving patient experience (Loya et al., 2023).

Smart and stimuli-responsive materials

Smart or stimuli-responsive materials represent an advanced class of restorative systems designed to adapt dynamically to changes in the oral environment. Unlike conventional materials with static properties, smart materials respond to specific triggers—such as pH fluctuations, temperature changes, or mechanical stress—to provide targeted protective or therapeutic effects (Atia et al., 2023; Aydın et al., 2023; Unnadkat et al., 2023).

Among the most extensively investigated smart systems are pH-responsive restorative materials, which exploit the acidic conditions associated with cariogenic biofilms. These materials are engineered to release ions or antimicrobial agents selectively under low pH conditions, thereby counteracting demineralization and bacterial activity during periods of heightened caries risk (Unnadkat et al., 2023). Such responsive behavior offers a promising strategy for addressing recurrent caries without continuous drug release, which may reduce unnecessary exposure and material fatigue.

Recent studies have described smart composites capable of modulating ion release or antimicrobial activity in response to environmental acidity, demonstrating significant reductions in bacterial viability in laboratory settings (Unnadkat et al., 2023). Antimicrobial smart materials often incorporate polymerizable quaternary ammonium compounds or similar agents that provide contact-based antibacterial effects while maintaining long-term stability within the restorative matrix (Aydın et al., 2023; Flores-Espinoza et al., 2023).

The clinical potential of smart restorative materials is particularly relevant for patients with high caries susceptibility, compromised oral hygiene, or complex restorative histories. By providing on-demand protective responses, these materials may complement conventional preventive strategies and enhance restoration longevity in challenging clinical contexts (Atia et al., 2023; Paradowska-Stolarz et al., 2023).

Nevertheless, challenges remain related to long-term durability, consistency of responsiveness over time, and potential material fatigue following repeated activation cycles. Ongoing advances in polymer chemistry and network design aim to improve stability and functional longevity while preserving responsiveness (Ortega et al., 2024). Future directions increasingly focus on multifunctional smart materials that integrate stimuli responsiveness with bioactivity, antimicrobial effects, and even self-healing capabilities, representing a holistic approach to next-generation restorative material design (Agrawal et al., 2023; Frąckiewicz et al., 2023).

Sustainable and environmentally conscious dental materials

Sustainability has emerged as an increasingly important consideration in dental material science, driven by growing awareness of the environmental impact associated with healthcare delivery and material manufacturing. In restorative dentistry, this has prompted efforts to reduce ecological burden through the development of materials and clinical workflows that minimize waste generation, limit the use of hazardous substances, and incorporate environmentally responsible design principles without compromising clinical performance (Alsaeed, 2022; Tavas et al., 2023).

One area of investigation has focused on life cycle assessment approaches to evaluate the environmental footprint of dental materials and associated consumables. Comparative analyses have demonstrated that reusable clinical kits and instruments can offer meaningful reductions in carbon emissions and material waste compared with single-use alternatives, particularly when sterilization processes are optimized and integrated into routine clinical workflows (Alsaeed, 2022). Such findings underscore the relevance of sustainability not only at the material level, but also across the broader restorative care pathway.

Material innovation has similarly explored the use of renewable or naturally derived components in restorative formulations. Experimental and early commercial composites incorporating bio-based fillers, such as cellulose-derived or plant-based particles, have shown promising mechanical performance while offering potential reductions in environmental impact. When appropriately engineered, these materials can maintain acceptable strength, wear resistance, and handling characteristics, suggesting feasibility for selected clinical applications (Ziaei et al., 2024). In parallel, manufacturers have increasingly pursued mercury-free restorative alternatives and recyclable or reduced packaging systems, reflecting both regulatory pressures and evolving professional expectations (Agrawal et al., 2023; Liang et al., 2023).

Despite these advances, challenges remain in balancing environmental sustainability with the stringent mechanical, biological, and esthetic requirements of restorative materials. Durability, longevity, and clinical reliability remain paramount, and any compromise in performance risks increasing restoration replacement rates, which would ultimately negate environmental gains. Ongoing research therefore emphasizes the development of sustainable biomaterials that meet or exceed existing clinical benchmarks while reducing ecological impact across their life cycle (Moharil et al., 2023; Ziaei et al., 2024).

Future directions in this domain increasingly draw on principles of green chemistry, including the use of less toxic monomers, energy-efficient manufacturing processes, and materials designed for safer disposal or recycling. As sustainability considerations become more integrated into regulatory frameworks and professional guidelines, environmentally conscious material selection is likely to become an integral component of evidence-based restorative practice rather than a peripheral concern (Tavas et al., 2023).

Advances in adhesive systems

Adhesive dentistry has undergone significant refinement over recent decades, with contemporary systems increasingly designed to simplify clinical protocols while maintaining reliable and durable bonding to enamel and dentin. The introduction of so-called universal or multi-mode adhesive systems represents a notable advance, as these materials can be applied using etch-and-rinse, self-etch, or selective-etch strategies, allowing clinicians to tailor their approach to specific clinical scenarios without changing products (Colak & Katirci, 2023; Lekhwani et al., 2023; Rues et al., 2024).

Recent analyses of the adhesive literature highlight sustained research interest in universal adhesives, particularly with respect to their chemical formulation and interaction with dentin. Functional monomers, such as 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP), play a critical role in enhancing chemical bonding to hydroxyapatite, contributing to improved bond durability and resistance to hydrolytic degradation (Rues et al., 2024). These advances address longstanding concerns regarding the stability of resin–dentin interfaces over time.

Beyond adhesion alone, emerging adhesive systems increasingly incorporate bioactive components aimed at enhancing interfacial integrity. Bioactive adhesives capable of releasing calcium, phosphate, or fluoride ions have been investigated for their potential to promote remineralization at the hybrid layer and reduce microleakage, particularly in challenging substrates such as caries-affected dentin (Carneiro et al., 2024; Fernandes et al., 2023). Such multifunctional designs reflect a broader trend toward adhesives that contribute actively to restoration longevity rather than serving solely as mechanical coupling agents.

Clinical and laboratory evaluations suggest that filled adhesive systems may offer advantages over unfilled formulations in certain applications, including non-carious cervical lesions, where stress distribution and marginal adaptation are critical (Colak & Katirci, 2023). High-resolution morphological studies further demonstrate that self-etch and universal adhesives can achieve more uniform infiltration of dentin substrates under appropriate moisture conditions, resulting in more consistent hybrid layer formation (Lekhwani et al., 2023).

Nevertheless, adhesive performance remains sensitive to technique-related factors, particularly moisture control and substrate variability. Excessive dentin wetness or desiccation can adversely affect bond strength, highlighting the continued importance of operator skill and protocol adherence. Innovations such as more hydrophobic resin matrices and improved solvent systems have been developed to mitigate technique sensitivity and enhance long-term bond stability (Flores-Espinoza et al., 2023; Rues et al., 2024).

Future developments in adhesive dentistry are expected to increasingly leverage nanotechnology to improve filler dispersion, mechanical reinforcement, and interfacial interaction at the nanoscale. Nano-enhanced adhesives hold promise for further improving durability and resistance to degradation, supporting the ongoing evolution of minimally invasive and long-lasting restorative strategies (Gallicchio et al., 2023; Uyumaz et al., 2024).

rESULTS AND DISCUSSION

The recent evolution of restorative dental materials, as documented in peer-reviewed literature published, reflects a fundamental shift in restorative dentistry from passive structural replacement toward biologically active, functionally adaptive, and patient-centered material systems. Collectively, advances in bioactive materials, nanotechnology, additive manufacturing, smart functionalities, sustainability-oriented design, and adhesive chemistry aim to address persistent clinical challenges such as secondary caries, interfacial degradation, material fatigue, and variability in patient-specific restorative needs.

Bioactive and ion-releasing materials: from restoration to therapeutic interface

Bioactive and ion-releasing materials represent one of the most transformative developments in contemporary restorative dentistry. Rather than acting solely as inert fillers, these materials extend the restorative concept toward therapeutic intervention by actively interacting with surrounding dental tissues (Atia et al., 2023; Christie et al., 2023; Fernandes et al., 2023; Sequeira et al., 2023; Li et al., 2024). Systematic reviews and meta-analyses indicate that materials incorporating calcium phosphate fillers, zinc-based components, or fluoride-releasing phases can enhance remineralization processes and support dentin regeneration, particularly in caries-prone environments (Atia et al., 2023; Fernandes et al., 2023; Xie et al., 2023; Li et al., 2024). Fernandes et al.’s network meta-analysis of randomized controlled trials demonstrated a reduced risk of secondary caries associated with bioactive restoratives, attributing this benefit to sustained ion release and improved interfacial stability (Fernandes et al., 2023).

Beyond restorative applications, bioactive materials have shown particular promise in vital pulp therapy and dentin–pulp complex regeneration. Studies investigating silicate-based cements, chitosan-modified scaffolds, and calcium-releasing liners report favorable outcomes in terms of pulp vitality preservation and reparative dentin formation (Christie et al., 2023; Paradowska-Stolarz et al., 2023; Sequeira et al., 2023). These effects are largely attributed to alkaline pH, bioavailable ion release, and the stimulation of odontoblastic differentiation. However, despite these biological advantages, mechanical limitations remain a concern. In vitro and clinical studies consistently report reduced wear resistance and fracture strength in high-load occlusal areas when compared with conventional resin composites (Liang et al., 2023; Chopra et al., 2024). Hybrid systems incorporating reinforced resin matrices have been proposed to address this limitation, but long-term clinical data remain limited (Flores-Espinoza et al., 2023; Xie et al., 2023). Furthermore, the lack of standardized definitions and testing methodologies for bioactivity complicates reproducibility and clinical translation, underscoring the need for consensus-driven evaluation frameworks (Atia et al., 2023; Moharil et al., 2023).

Nanomaterials as enablers of mechanical, biological, and esthetic performance

Nanomaterials have emerged as a pivotal trend in restorative dentistry by enabling simultaneous enhancement of mechanical properties, antimicrobial performance, and esthetic stability (Carneiro et al., 2023; Gallicchio et al., 2023; Unnadkat et al., 2023; Urkande et al., 2023; Ziaei et al., 2024). Reviews of nanoscience applications in dentistry highlight how nanoparticles such as β-tricalcium phosphate, zeolites, and halloysite nanotubes reduce dentin permeability, inhibit bacterial adhesion, and improve resin–dentin bonding integrity (Agrawal et al., 2023; Unnadkat et al., 2023; Urkande et al., 2023; Woźniak-Budych et al., 2023). Woźniak-Budych et al. emphasized that nanomaterials doped with antimicrobial agents, such as chlorhexidine, provide sustained antibacterial effects while maintaining physicomechanical stability (Agrawal et al., 2023; Urkande et al., 2023).

Clinical implications of nanotechnology include improved polishability, color stability, and marginal adaptation of nano-hybrid composites, particularly in caries-affected dentin (Christie et al., 2023; Frąckiewicz et al., 2023; Chopra et al., 2024). Nevertheless, concerns persist regarding long-term biocompatibility, nanoparticle release, and potential cytotoxicity. Several reviews emphasize the necessity of rigorous in vivo studies and standardized safety assessments to mitigate these risks (Urkande et al., 2023; Ziaei et al., 2024). Importantly, recent research increasingly positions nanomaterials not as standalone solutions, but as enabling platforms that synergize with bioactive components, resulting in hybrid systems that enhance remineralization while maintaining mechanical durability (Carneiro et al., 2023; Gallicchio et al., 2023).

Additive manufacturing and digital customization of restorations

Additive manufacturing technologies, particularly three-dimensional (3D) printing, have fundamentally altered the fabrication landscape of restorative dentistry by enabling precise, patient-specific designs and efficient material utilization (Chacón Gahona et al., 2023; Colak & Katirci, 2023; Lekhwani et al., 2023; Loya et al., 2023; Tavas et al., 2023; Atta et al., 2024; NWNA et al., 2024; Uyumaz et al., 2024). Reviews of dental 3D printing technologies describe applications ranging from crowns and copings to periodontal scaffolds and hard tissue engineering constructs, often demonstrating superior marginal fit and internal adaptation compared with traditional techniques (Loya et al., 2023; Tavas et al., 2023; Uyumaz et al., 2024). Comparative studies evaluating additively manufactured zirconium oxide ceramics and reinforced acrylic resins report mechanical properties comparable to subtractively milled counterparts, supporting their use in selected prosthodontic applications (Colak & Katirci, 2023; Lekhwani et al., 2023; Loya et al., 2023; Tavas et al., 2023).

Despite these advantages, challenges remain related to post-curing effects, color stability, wear resistance, and cytotoxic potential of printable resins (NWNA et al., 2024; Rues et al., 2024). In vitro studies indicate that sintering protocols, layer thickness, and printing orientation significantly influence mechanical performance and long-term stability (Chacón Gahona et al., 2023; Colak & Katirci, 2023; Lekhwani et al., 2023). While additive manufacturing offers clear benefits in reducing chair time and material waste, further longitudinal clinical studies are required to validate the durability of printed restorations in the oral environment (Aydın et al., 2023; Atta et al., 2024).

Smart and stimuli-responsive materials: toward adaptive restorations

Smart and stimuli-responsive materials introduce a dynamic dimension to restorative dentistry by enabling restorations to respond to environmental changes such as pH fluctuations, temperature variation, or mechanical stress (Alsaeed, 2022; Fronza et al., 2022; Kodaira et al., 2022; Alshabib et al., 2023; Luo et al., 2024; Maravić et al., 2023; Ortega et al., 2024). pH-responsive composites and glass hybrids are particularly relevant in cariogenic environments, where acidic conditions trigger ion release or antimicrobial activity, thereby counteracting demineralization and biofilm progression (Alshabib et al., 2023; Luo et al., 2023; Ortega et al., 2024). Clinical trials evaluating smart bulk-fill materials and monochromatic composites report acceptable mechanical performance and resistance to discoloration, even following exposure to whitening agents (Alsaeed, 2022; Alshabib et al., 2023; Luo et al., 2023).

Emerging applications also include shape-memory polymers in orthodontics and adaptive polymer networks in implant dentistry (Kodaira et al., 2022; Ortega et al., 2024). However, variability in activation thresholds, long-term functional stability, and concerns regarding genotoxicity in certain metallic smart materials highlight the need for cautious clinical translation (Kodaira et al., 2022). Future research increasingly focuses on integrating smart behavior with nanotechnology and bioactivity to develop multifunctional systems capable of self-healing, antimicrobial response, and tissue interaction (Fronza et al., 2022; Maravić et al., 2023).

Sustainability and environmental considerations in restorative materials

Although sustainability-focused dental materials remain an emerging research area, indirect evidence from multiple domains indicates growing attention to environmentally conscious design (Moharil et al., 2023; Tavas et al., 2023; Urkande et al., 2023). Studies investigating polyetheretherketone (PEEK) biomaterials, natural-derived hydrogels, and biodegradable scaffolds suggest that environmentally friendly alternatives can achieve acceptable biocompatibility and mechanical performance (Carneiro et al., 2023; Moharil et al., 2023). Additionally, additive manufacturing inherently supports waste reduction through precise material deposition, aligning restorative dentistry with broader sustainability goals (Lekhwani et al., 2023; Tavas et al., 2023).

Life-cycle considerations, including reduced reliance on mercury-containing materials and increased use of recyclable packaging, further support this trend (Atia et al., 2023; Liang et al., 2023). However, sustainability must be balanced against clinical durability, as premature restoration failure would negate environmental benefits. Consequently, future research should prioritize materials that achieve both long-term clinical reliability and reduced ecological impact.

Advances in adhesive systems and interfacial stability

Advances in adhesive dentistry underpin many of the material innovations discussed above. Universal and bioactive adhesive systems have simplified bonding protocols while improving interfacial stability across diverse substrates (Atia et al., 2023; Christie et al., 2023; Fernandes et al., 2023; Liang et al., 2023; Moharil et al., 2023; Paradowska-Stolarz et al., 2023; Sequeira et al., 2023; Xie et al., 2023; Chopra et al., 2024; Li et al., 2024). Reviews of contemporary adhesive generations report enhanced performance in direct restorations, particularly through the use of functional monomers such as 10-MDP and improved solvent systems (Sequeira et al., 2023; Li et al., 2024). Bioactive adhesives capable of releasing calcium and phosphate ions further contribute to remineralization at the hybrid layer, reducing microleakage and interfacial degradation (Fernandes et al., 2023; Paradowska-Stolarz et al., 2023).

Table 2 summarizes the clinical relevance, evidence maturity, and future research priorities associated with emerging restorative dental material technologies.

Table 2. Clinical Translation and Research Gaps in Emerging Restorative Dental Materials

Agrawal, R., Bajaj, P., Shirbhate, U., Reche, A., Pahade, A., & Barhate, A. (2023). Clinical implications of nanosciences in dentistry and periodontics: a narrative review. Cureus, 15(11), e48593. doi:10.7759/cureus.48593

Alsaeed, A. Y. (2022). Bonding CAD/CAM materials with current adhesive systems: An overview. The Saudi Dental Journal, 34(4), 259-269. doi:10.1016/j.sdentj.2022.03.005

Alshabib, A., Abid Althaqafi, K., AlMoharib, H. S., Mirah, M., AlFawaz, Y. F., & Algamaiah, H. (2023). Dental fiber-post systems: an in-depth review of their evolution, current practice and future directions. Bioengineering, 10(5), 551. doi:10.3390/bioengineering10050551

Atia, G. A., Shalaby, H. K., Roomi, A. B., Ghobashy, M. M., Attia, H. A., Mohamed, S. Z., Abdeen, A., Abdo, M., Fericean, L., Bănățean Dunea, I., et al. (2023). Macro, micro, and nano-inspired bioactive polymeric biomaterials in therapeutic, and regenerative orofacial applications. Drug Design, Development and Therapy, 2985-3021. doi:10.2147/DDDT.S419361

Atta, I., Bourauel, C., Alkabani, Y., Mohamed, N., Kim, H., Alhotan, A., Ghoneima, A., & Elshazly, T. (2024). Physiochemical and mechanical characterisation of orthodontic 3D printed aligner material made of shape memory polymers (4D aligner material). Journal of the Mechanical Behavior of Biomedical Materials, 150, 106337. doi:10.1016/j.jmbbm.2023.106337

Aydın, N., Karaoğlanoğlu, S., Kılıç-Süloğlu, A., & Öztürk, S. (2023). Comparison of the cytotoxic effect of 3D-printed resins, resin-based CAD/CAM blocks and composite resin. Journal of Clinical and Experimental Dentistry, 15(12), e984-e990. doi:10.4317/jced.60987

Carneiro, B. T., Kury, M., Lopes, J. C., Gonçalves, R. S., Suzuki, T. Y. U., PICOLO, M. Z. D., Giannini, M., & André, C. B. (2023). Effect of whitening toothpastes and activated charcoal powder on enamel wear and surface roughness. Brazilian oral Research, 37, e092. doi:10.1590/1807-3107bor-2023.vol37.0092

Chacón Gahona, K. B., Morales Bravo, B. R., Vintimilla Coronel, S. E., & Sarmiento Criollo, P, F. (2023). Evolution and effectiveness of seventh and eighth generation adhesive systems in direct restorations. a review. Revista Cientifica Odontologica (Universidad Cientifica del Sur), 11(4), e178-e178. doi:10.21142/2523-2754-1104-2023-178

Chopra, D., Guo, T., Gulati, K., & Ivanovski, S. (2024). Load, unload and repeat: Understanding the mechanical characteristics of zirconia in dentistry. Dental Materials, 40(1), e1-e17. doi:10.1016/j.dental.2023.10.007

Christie, B., Musri, N., Djustiana, N., Takarini, V., Tuygunov, N., Zakaria, M. N., & Cahyanto, A. (2023). Advances and challenges in regenerative dentistry: a systematic review of calcium phosphate and silicate-based materials on human dental pulp stem cells. Materials Today Bio, 23, 100815. doi:10.1016/j.mtbio.2023.100815

Colak, G., & Katirci, G. (2023). In Vitro evaluation of the effects of whitening toothpastes on the color and surface roughness of different composite resin materials. BMC Oral Health, 23(1), 580. doi:10.1186/s12903-023-03277-4

Fernandes, J. B., Contreras, S. M., da Silva Spinola, M., Batista, G. R., Bresciani, E., & Caneppele, T. M. F. (2023). Do bioactive materials show greater retention rates in restoring permanent teeth than non-bioactive materials? A systematic review and network meta-analysis of randomized controlled trials. Clinical Oral Investigations, 28(1), 44. doi:10.1007/s00784-023-05414-3

Flores-Espinoza, A. I., Garcia-Contreras, R., Guzman-Rocha, D. A., Aranda-Herrera, B., Chavez-Granados, P. A., Jurado, C. A., Alfawaz, Y. F., & Alshabib, A. (2023). Gelatin–chitosan hydrogel biological, antimicrobial and mechanical properties for dental applications. Biomimetics, 8(8), 575. doi:10.3390/biomimetics8080575

Frąckiewicz, W., Królikowski, M., Kwiatkowski, K., Sobolewska, E., Szymlet, P., & Tomasik, M. (2023). Comparison of dental zirconium oxide ceramics produced using additive and removal technology for prosthodontics and restorative dentistry—strength and surface tests: An in vitro study. Materials, 17(1), 168. doi:10.3390/ma17010168

Fronza, B. M., Braga, R. R., & Cadenaro, M. (2022). Dental adhesives—Surface modifications of dentin structure for stable bonding. Dental Clinics, 66(4), 503-515. doi:10.1016/j.cden.2022.05.002

Gallicchio, V., Spinelli, V., Russo, T., Marino, C., Spagnuolo, G., Rengo, C., & De Santis, R. (2023). Highly reinforced acrylic resins for hard tissue engineering and their suitability to be additively manufactured through nozzle-based photo-printing. Materials, 17(1), 37. doi:10.3390/ma17010037

Kodaira, A., Koizumi, H., Hiraba, H., Takeuchi, Y., Koike, M., & Shimoe, S. (2022). Bonding of resin luting materials to titanium and titanium alloy. Journal of Oral Science, 64(3), 181-184. doi:10.2334/josnusd.22-0036

Lekhwani, P. S., Nigam, A. G., Marwah, N., & Jain, S. (2023). Comparative evaluation of Tell-Show-Do technique and its modifications in managing anxious pediatric dental patients among 4–8 years of age. Journal of Indian Society of Pedodontics and Preventive Dentistry, 41(2), 141-148. doi:10.4103/jisppd.jisppd_242_23

Li, L. J., Chu, C. H., & Yu, O. Y. (2023). Application of zeolites and zeolitic imidazolate frameworks in dentistry—a narrative review. Nanomaterials, 13(22), 2973. doi:10.3390/nano13222973

Li, P., Dai, J., Li, Y., Alexander, D., Čapek, J., Geis-Gerstorfer, J., Wan, G., Han, J., Yu, Z., & Li, A. (2024). Zinc based biodegradable metals for bone repair and regeneration: Bioactivity and molecular mechanisms. Materials Today Bio, 25, 100932. doi:10.1016/j.mtbio.2023.100932

Liang, J., Lu, X., Zheng, X., Li, Y. R., Geng, X., Sun, K., Cai, H., Jia, Q., Jiang, H. B., & Liu, K. (2023). Modification of titanium orthopedic implants with bioactive glass: A systematic review of in vivo and in vitro studies. Frontiers in Bioengineering and Biotechnology, 11, 1269223. doi:10.3389/fbioe.2023.1269223

Loya, P. R., Nikhade, P. P., Paul, P., Reche, A., & Loya, P. (2023). Be smart and active in conservative dentistry and endodontics. Cureus, 15(10), e47185. doi:10.7759/cureus.47185

Luo, C., Liu, Y., Peng, B., Chen, M., Liu, Z., Li, Z., Kuang, H., Gong, B., Li, Z., & Sun, H. (2023). PEEK for oral applications: recent advances in mechanical and adhesive properties. Polymers, 15(2), 386. doi:10.3390/polym15020386

Maravić, T., Mazzitelli, C., Mancuso, E., Del Bianco, F., Josić, U., Cadenaro, M., Breschi, L., & Mazzoni, A. (2023). Resin composite cements: Current status and a novel classification proposal. Journal of Esthetic and Restorative Dentistry, 35(7), 1085-1097. doi:10.1111/jerd.13036

Moharil, S., Reche, A., Durge, K., & Moharil, S. S. (2023). Polyetheretherketone (PEEK) as a biomaterial: an overview. Cureus, 15(8), e44307. doi:10.7759/cureus.44307

NWNA, M., R, A., NH, K. A., E, S., MAA, K., MH, I., LK, T., & MZ, S.. (2024). In vitro evaluation of cytotoxicity and genotoxicity of porous nickel titanium dental implants produced by metal injection molding technique. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 112(1), e35306. doi:10.1002/jbm.b.35306

Ortega, M. A., Rios, L., Fraile Martínez, O., Liviu Boaru, D., Leon Oliva, D. D., Barrena Blázquez, S., Pereda Cerquella, C., Garrido Gil, M. J., Manteca, L., Buján, J., et al. (2024). Bioceramic versus traditional biomaterials for endodontic sealers according to the ideal properties. Histology and Histopathology, 39(3), 279-292. doi:10.14670/HH-18-664

Paradowska-Stolarz, A., Mikulewicz, M., Laskowska, J., Karolewicz, B., & Owczarek, A. (2023). The importance of chitosan coatings in dentistry. Marine Drugs, 21(12), 613. doi:10.3390/md21120613

Rues, S., Herpel, C., Ilani, A., Schmitt, C., Rammelsberg, P., & Schwindling, F. S. (2024). Effect of firing time and wall thickness on the biaxial flexural strength of 3D-printed zirconia. Dental Materials, 40(3), 484-492. doi:10.1016/j.dental.2023.12.018

Sequeira, D. B., Diogo, P., Gomes, B. P., Peça, J., & Santos, J. M. M. (2023). Scaffolds for dentin–pulp complex regeneration. Medicina, 60(1), 7. doi:10.3390/medicina60010007

Tavas, B., Celiksoz, O., Tepe, H., Ozaslan, S., & Yaman, B. C. (2023). The effect of whitening toothpastes on the color stability of a smart monochromatic composite resin. Cureus, 15(9), e46225. doi:10.7759/cureus.46225

Unnadkat, A., Kirby, L., Kulanthaivel, S., Rysavy, O., Tsujimoto, A., Song, X., & Teixeira, E. C. (2023). The effect of sintering on zirconia manufactured via suspension-enclosing projection stereolithography for dental applications: An in vitro study. Materials, 17(1), 14. doi:10.3390/ma17010014

Urkande, N. K., Mankar, N., Nikhade, P. P., & Chandak, M. (2023). Understanding the complexities of cast post retention: A comprehensive review of influential factors. Cureus, 15(12), e51258. doi:10.7759/cureus.51258

Uyumaz, F. Ü., Abaklı İnci, M., & Özer, H. (2024). Could bulk fill glass hybrid restorative materials replace composite resins in treating permanent teeth? A randomized controlled clinical trial. Journal of Esthetic and Restorative Dentistry, 36(5), 702-709. doi:10.1111/jerd.13181

Woźniak-Budych, M. J., Staszak, M., & Staszak, K. (2023). A critical review of dental biomaterials with an emphasis on biocompatibility. Dental and Medical Problems, 60(4), 709-739. doi:10.17219/dmp/172732

Xie, Y., Chen, R., Yao, W., Ma, L., & Li, B. (2023). Synergistic effect of ion-releasing fillers on the remineralization and mechanical properties of resin–dentin bonding interfaces. Biomedical Physics & Engineering Express, 9(6), 062001. doi:10.1088/2057-1976/ad0300

Ziaei, M., Bajoghli, F., Sabouhi, M., Jowkar, M., Nadian, F., & Manshaei, F. (2024). Evaluating the Marginal and Internal Discrepancy of Nickel–Chrome Copings Made on Fixed Partial Denture Implants with Conventional and 3D Printing Techniques. The Journal of Contemporary Dental Practice, 24(11), 826-833. doi:10.5005/jp-journals-10024-3586