1. Introduction

Full-arch implant restorations represent a pinnacle in modern dentistry, offering patients an unparalleled opportunity for functional rehabilitation and esthetic restoration [1]. As the demand for comprehensive solutions to edentulism continues to rise, the choice of materials in crafting these restorations becomes an essential element in achieving long-term success [2].

The landscape of dental materials has undergone a profound transformation over the years, with the emergence of both hybrid and monolithic options [3]. This chapter embarks on a journey through the dynamic debate surrounding the selection of materials for full-arch implant restorations, exploring the nuanced considerations that clinicians must navigate in the pursuit of optimal outcomes [4].

Historically, dental prosthetics were crafted from materials that prioritized durability and functionality [5]. However, the evolving expectations of patients, coupled with advancements in material science, have given rise to a spectrum of possibilities [6]. From the traditional layered composites to the modern monolithic zirconia, the array of choices can be both empowering and daunting [7].

As clinicians, we stand at a crossroads where decisions regarding material selection not only impact the mechanical properties of restorations but also influence the esthetic, biocompatible, and long-term performance aspects. This chapter aims to dissect the dichotomy between hybrid and monolithic materials, offering an in-depth analysis of their respective strengths, weaknesses, and the clinical scenarios where one may excel over the other.

Join us on this exploration of the materials that form the foundation of full-arch implant restorations, as we navigate the complexities, weigh the evidence, and consider the implications for the future of prosthetic dentistry.

2. Historical perspective

2.1 Early materials in full-arch restorations

The journey of full-arch restorations traces back to a time when dental prosthetics were primarily crafted from materials such as acrylic resins and metal alloys [8]. These early materials, though foundational, posed challenges in terms of esthetics, durability, and biocompatibility (Figures 1 and 2).

Figure 1.
Photo of a full-arch restoration with the first generation of layered composite on top of a cobalt-chrome frame.

Figure 2.
Orthopantomography of the same patient, as in Figure 1, for the final treatment assessment.

2.2 Rise of Porcelain-Fused-to-Metal (PFM) restorations

The advent of Porcelain-Fused-to-Metal (PFM) marked a significant shift in full-arch restorations, offering a balance between strength and esthetics [9]. The metal substructure provided durability, while the porcelain overlay addressed esthetic concerns. PFM became a standard for many years, contributing to the restoration of edentulous arches (Figure 3).

Figure 3.
Photos of a PFM restoration at the end of treatment.

2.3 Challenges and limitations of traditional materials

Despite their prevalence, traditional materials like PFM had inherent limitations. Issues such as chipping of porcelain, difficulties in achieving natural translucency, and the challenge of maintaining harmonious gingival contours prompted a quest for alternative solutions (Figure 4) [10].

Figure 4.
PFM full-arch restoration with one of the most associated issues – The occurrence of porcelain chipping. There are several reasons (thickness of the porcelain layer, occlusal forces, brittleness of porcelain, incorrect occlusion or patient habits, misfit) why such problems may appear, and, in these cases, alternative materials must be chosen.

2.4 Introduction of CAD/CAM technology

The introduction of Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) technology revolutionized the field. This shift enabled the production of more precise (Figure 5) and patient-specific restorations, reducing the dependence on manual labor and facilitating the use of novel materials [11].

Figure 5.
Section of intraoral radiography of a restoration where can be seen the precision of the perfect fit of CAD/CAM restorations on implants.

2.5 Emergence of hybrid materials

Hybrid materials, combining a metal or zirconia framework with layered injected composites, entered the scene as a response to the limitations of traditional materials [12]. These materials aimed to capitalize on the strength of the substructure while enhancing esthetics through more lifelike surface layers (Figure 6).

Figure 6.
Photo of a full-arch restoration with hybrid materials (latest injected composite on a milled metal frame) that emphasizes the improvement of the esthetic aspects of the restoration.

2.6 Contemporary landscape and material diversity

In recent years, the landscape of full-arch restorations has become increasingly diverse. Materials like high-performance polymers, advanced ceramics, and monolithic multilayered zirconia (Figure 7) have gained popularity, offering clinicians a spectrum of options to address the unique needs of each case [13].

Figure 7.
Photo of several restorations made of the latest monolithic multilayered zirconia.

2.7 Impact on clinical outcomes

The evolution of materials in full-arch restorations has had a profound impact on clinical outcomes. Improved strength, enhanced esthetics, and a growing emphasis on patient-specific solutions have shaped the contemporary approach to full-arch implant restorations.

This historical perspective sets the stage for a comprehensive exploration of the contemporary debate between hybrid and monolithic materials, shedding light on the factors that have influenced their evolution and the implications for clinical practice.

3. Contemporary material options

3.1 Overview of material landscape

In the rapidly advancing field of full-arch implant restorations, clinicians find themselves at the intersection of innovation and tradition, tasked with navigating a diverse material landscape. The choice of materials is no longer a mere technical decision but a pivotal factor influencing the functional, esthetic, and long-term success of the restoration (Table 1).

Materials	Hybrid materials	Monolithic materials
Definition	Hybrid materials represent a sophisticated amalgamation of strength and esthetics. This approach involves the strategic combination of a sturdy substructure, often composed of metals or high-strength ceramics like zirconia, with layered composite or ceramic materials for the visible surface.	Monolithic materials, in contrast, embody simplicity and strength. These materials, such as monolithic zirconia or other high-strength ceramics, maintain a uniform composition throughout the entire restoration.
Composition	The foundational strength of the hybrid lies in its substructure, which provides durability and support. This is then layered with composite materials or ceramics to achieve the desired esthetic appearance. The layering process allows for the customization of color, translucency, and surface texture, mimicking the natural dentition.	These restorations are typically milled or produced from a single block of material (Figure 8), ensuring homogeneity in strength and color. Monolithic zirconia, for instance, boasts exceptional durability and resistance to wear.
Advantages	Esthetic versatility: Layering techniques offer a broad spectrum of esthetic possibilities, enabling clinicians to achieve lifelike results. Strength and support: The robust substructure ensures the restoration’s durability and stability. Repairability: In the event of minor issues, some hybrid restorations can be adjusted or repaired chairside.	Strength and durability: Monolithic materials offer high resistance to fractures and chipping due to their uniform composition. Streamlined fabrication: The manufacturing process is often quicker and more straightforward than the intricate layering involved in hybrids. Consistency: The entire restoration exhibits consistent color and strength.
Challenges	Complex fabrication: The intricate layering process demands skilled technicians and may lengthen the fabrication timeline. Maintenance considerations: The layered nature of hybrid materials may pose challenges in terms of wear and tear over time (Figure 9).	Esthetic limitations: While advancements have been made, monolithic materials may have limited variability in achieving natural esthetics compared to hybrids. Adjustment challenges: Chairside adjustments can be more challenging due to the hardness of the material.

Table 1.

Materials comparison: Hybrid vs. monolithic.

Figure 8.
Photos a and b are print screens performed before starting the milling machine and pictures c and d are examples of a single block of material before and after it is milled.

Figure 9.
Photo of a hybrid full-arch restoration that exposes the wear and tear over time because of the layered nature of hybrid materials composite on metal frame.

3.2 Considerations in material selection

As clinicians navigate the landscape of hybrid and monolithic materials, several crucial considerations come into play. Patient preferences, the specific clinical context, and the overarching treatment goals should guide the decision-making process. This comprehensive overview sets the stage for a deeper exploration of the clinical considerations, esthetic implications, and long-term performance associated with the utilization of hybrid and monolithic materials in full-arch restorations.

Choosing the right materials for full-arch implant restorations is a critical decision for dentists. Essentially, we have two main options: hybrid materials and monolithic materials. Hybrid materials are like a blend of different layers, combining a strong base with detailed surface elements. On the other hand, monolithic materials are more straightforward, with a solid, uniform structure.

Now, why does this decision matter so much? Well, it is about tailoring the solution to each patient’s unique needs. Think of it as fitting puzzle pieces together in the mouth.

First off, we consider the available space. Hybrid materials might require a bit more room due to their layered nature. Then, there’s the esthetic aspect—ensuring the replacement teeth look natural. Hybrids give us more flexibility here, allowing for customization in color and texture.

We also factor in things like teeth grinding and the health of the jaw joints (TMJ). Some people grind their teeth, so we need materials that can withstand that. And the materials should work well with the jaw joints to ensure long-term health.

Considering the impact on opposing teeth—the ones the new implants will bite against—is crucial. We want a material that will not cause excessive wear and tear on these natural teeth. Patient age comes into play, too; younger and older mouths may require different considerations.

So, it is a bit like being a chef in a kitchen—selecting the right ingredients for the perfect dish. We want the implant to be durable, esthetically pleasing, and seamlessly integrated into each person’s individual oral puzzle.

4. Clinical considerations

The choice between hybrid and monolithic materials is deeply influenced by several clinical factors. The patient’s overall oral health, including the condition of existing teeth and supporting structures, is a pivotal consideration. The periodontal status, particularly the health of the gums and surrounding tissues, can influence the decision, with hybrid materials often offering advantages in achieving harmonious gingival contours. Restoration complexity, such as the number of missing teeth and the overall restoration design, plays a role in guiding the selection process. Additionally, understanding the patient’s occlusal dynamics, including bite alignment and potential parafunctional habits, is critical in determining the most suitable material.

4.1 Prosthetic space

Definition and importance: Prosthetic space refers to the available vertical and horizontal space within the oral cavity for accommodating dental restorations [14]. It encompasses the height and width required for fixed dental prostheses, considering factors such as adjacent teeth, occlusal clearance, and bone volume. The adequate availability of prosthetic space is crucial for determining the type of restoration that can be accommodated.
Influence on material selection: Prosthetic space significantly influences the choice between hybrid and monolithic materials. Hybrid materials might necessitate more space due to their layered construction, whereas monolithic materials, being more conservative in space requirements, could be more suitable in cases with limited available space.
Diagnostic assessment: Accurate measurement and assessment of prosthetic space involve thorough diagnostic procedures, including radiographic evaluation, digital impressions, and clinical measurements. These assessments aid in determining the feasibility of different restoration types and material choices based on the available space.
Treatment planning considerations: Prosthetic space evaluation is a critical aspect of treatment planning for full-arch restorations. Clinicians must consider the ideal dimensions required for the chosen restoration type and material, ensuring a proper fit, functional occlusion, and long-term success.
Clinical challenges and solutions: In cases of limited prosthetic space, clinicians may face challenges in selecting and designing appropriate restorations. Techniques such as minimal preparation or modification of the abutment teeth might be employed to optimize available space without compromising the restoration’s integrity.
Long-term implications: The consideration of prosthetic space extends to the long-term success of the restoration. Insufficient space can lead to complications such as poor fit, compromised occlusion, and potential mechanical failures. Adequate space ensures proper adaptation, stability, and functional harmony of the restoration within the oral environment (Table 2).

Aspect	Monolithic materials	Hybrid materials
Space requirements	Demand less space due to compact, single-block fabrication (See Figure 10)	Require more space for layered construction
Strength and durability	Exhibit exceptional strength and durability despite compactness	Offer good strength, may require meticulous handling
Fit and adaptation	Fit well within confined spaces without compromising integrity	May face challenges fitting in limited spaces
Esthetic customization	Limited esthetic customization but adequate natural appearance	Allow intricate customization for lifelike esthetics
Clinical considerations	Suitability for limited space cases, ensuring durable fit	Versatility in achieving detailed esthetics
Long-term implications	Proper adaptation within limited space ensures functional harmony	May face difficulties in cases with constrained space

Table 2.

Comparison of monolithic and hybrid materials in prosthetic space considerations.

Figure 10.
Photo of a monolithic full-arch restoration where can be easily observed the suitability for limited space cases, ensuring long-term success.

4.2 Esthetic considerations

Importance of esthetics: Esthetics serve as a cornerstone in full-arch restorations, influencing patient satisfaction, self-esteem, and overall treatment success. Achieving natural-looking teeth is paramount, especially in the anterior region, where visual prominence is heightened [15].
Material influence on esthetics: The selection between monolithic and hybrid materials substantially influences the final esthetic outcome. Hybrid materials offer unparalleled versatility in replicating natural tooth characteristics [4]. This adaptability enables intricate color matching, translucency modulation, and surface texture emulation, ensuring a striking resemblance to natural dentition. Conversely, monolithic materials may exhibit limitations in precisely replicating the detailed esthetics of natural teeth due to their homogeneous structure [15].
Customization for natural appearance: Hybrid materials stand out for their ability to achieve detailed customization, facilitating the recreation of the nuanced complexities of natural dentition [4]. Their diverse shades, translucency options, and surface textures allow for meticulous replication of natural teeth, ensuring seamless integration with adjacent dentition. However, monolithic materials, though lacking the intricate customization capabilities of hybrids, offer consistent and reliable uniformity, catering well to cases that demand durability over nuanced esthetics [16].
Patient expectations and satisfaction: Understanding and aligning with patient expectations regarding esthetics are critical for successful full-arch restorations. Patients often harbor high expectations for a natural-looking smile [17]. Managing these expectations while considering the strengths and limitations of chosen materials is pivotal in achieving patient satisfaction and acceptance of the final esthetic outcome.
Longevity and stability of esthetic results: Assessing the long-term stability and durability of esthetic outcomes is crucial [15]. Both monolithic and hybrid materials may provide satisfactory initial esthetic results, but considerations of long-term color stability, surface integrity, and wear resistance are paramount to ensure enduring esthetic appeal.
Clinical techniques and enhancements: Beyond material choice, attention to clinical techniques significantly contributes to superior esthetic outcomes. Prudent tooth preparation, meticulous restoration design, precise shade matching, and attention to contouring and surface texture play pivotal roles in enhancing overall esthetics, irrespective of the chosen material type (Figure 11) [17].

Figure 11.
Photos of a hybrid full-arch restoration that emphasizes the advantages of utilizing hybrid materials (the latest generation of injected composite) for achieving natural esthetics.

5. Monolithic vs. hybrid materials in esthetic performance

5.1 Monolithic materials: esthetic integrity vs. uniformity

Proponents of monolithic materials advocate for their structural integrity and uniformity, attributing these characteristics to enhanced strength and resistance to fractures. The homogeneous composition of materials like zirconia or lithium disilicate offers consistent color and translucency throughout the restoration, ensuring durability and longevity. However, while these materials excel in strength, their limitations lie in the difficulty of achieving nuanced esthetic details. The uniform structure may impede the replication of natural tooth complexities, especially in mimicking fine color gradients and subtle surface textures. This uniformity can result in restorations that appear less natural in complex esthetic cases requiring intricate customization.

5.2 Hybrid materials: versatility for natural Esthetics

Advocates for hybrid materials emphasize their versatility in replicating natural tooth esthetics with precision. The layered construction, combining a strong substructure (e.g., zirconia or metal) with esthetic layers of ceramics or composite resins, offers unparalleled customization possibilities. This versatility allows for lifelike translucency, color variation, and intricate surface texture, closely resembling natural dentition. However, the layering technique, while enabling detailed customization, may introduce challenges such as potential chipping or delamination between layers, demanding meticulous fabrication and handling during adjustments.

The comparison between monolithic and hybrid materials for esthetic performance in full-arch restorations accentuates the trade-off between reliability and versatility. Monolithic materials, valued for their uniformity and durability, might compromise nuanced esthetic details, especially in complex cases. Hybrid materials, offering versatility for natural esthetics, may demand careful handling due to the layered construction but excel in replicating natural tooth complexities.

The decision hinges on balancing clinical requirements, patient expectations, and material capabilities. Monolithic materials, while providing strength and reliability, may be preferred for cases prioritizing durability over nuanced esthetics. Hybrid materials, though requiring meticulous handling, shine in cases where precise esthetic customization is crucial for achieving natural-looking outcomes.

5.3 Bruxism

Impact of bruxism: Bruxism, characterized by teeth grinding or clenching, poses significant challenges in full-arch restorations [18]. The excessive occlusal forces exerted by bruxism can lead to increased mechanical stress on dental restorations, potentially compromising their longevity and structural integrity [19].
Material influence on bruxism: In cases of bruxism, material selection plays a critical role in ensuring restoration durability. Monolithic materials, recognized for their high strength and resistance to fractures, are often preferred for bruxers [20]. These materials, like zirconia or high-strength ceramics, exhibit superior mechanical properties, providing better resistance against the abrasive forces associated with bruxism. Conversely, hybrid materials, despite their esthetic advantages, may be more susceptible to wear or damage due to their layered construction and varied material compositions.
Clinical management strategies: Managing full-arch restorations in bruxism cases necessitates a comprehensive approach. Thorough occlusal analysis, precise occlusal adjustments, and occlusal splints play vital roles in mitigating the adverse effects of bruxism on restorations [19]. Additionally, meticulous polishing and surface treatments of restorations can enhance their wear resistance and reduce the likelihood of wear-induced complications.
Long-term implications: Bruxism poses a considerable challenge in the long-term success of full-arch restorations [18]. The continuous occlusal forces exerted during bruxism may lead to wear, chipping, or fracture of restorative materials over time. Monitoring and regular follow-ups are crucial to detect and address potential complications early, ensuring the restoration’s longevity in bruxism patients.

Bruxism significantly impacts full-arch restorations, necessitating careful consideration during material selection and clinical management. While monolithic materials offer superior strength and resistance to occlusal forces, they might be preferred for cases involving bruxism. However, comprehensive management strategies involving meticulous occlusal analysis and maintenance are vital for ensuring the long-term success of restorations in bruxism patients.

Monolithic materials, exemplified by zirconia, are distinguished by their exceptional strength and durability, making them highly resilient to fractures associated with bruxism [18, 19]. Their homogeneous structure contributes to enhanced material integrity, enabling greater resistance against wear and chipping caused by bruxing forces [19]. In clinical settings, monolithic materials often afford straightforward adaptability, requiring minimal adjustments and facilitating ease in managing occlusal discrepancies attributed to bruxism [20].

On the other hand, hybrid materials, characterized by their layered construction, present a nuanced scenario. While offering potential esthetic advantages, these materials might pose challenges in maintaining cohesive strength and durability under the continuous occlusal forces of bruxism. The layered composition in hybrid materials increases the susceptibility to delamination or fractures, potentially compromising their longevity and structural integrity, especially in cases of bruxism. Clinical adaptation with hybrid materials could demand meticulous handling and frequent adjustments, potentially posing challenges in managing the restoration’s integrity under the continuous bruxing forces [19].

In summary, monolithic materials like zirconia demonstrate robust strength and durability, offering resilience against wear and fractures associated with bruxism. Their uniform structure and clinical adaptability might provide advantages in managing cases of bruxism. Conversely, hybrid materials, while potentially offering esthetic advantages, may pose challenges in maintaining material integrity and clinical adaptability in cases involving continuous bruxing forces.

5.4 TMJ issues

Impact of TMJ health: The health of the temporomandibular joint (TMJ) holds significant importance in the success of full-arch restorations. TMJ disorders can affect occlusal stability, leading to challenges in treatment planning and execution [21].
Material influence on TMJ: Material selection in full-arch restorations can significantly influence TMJ health. Monolithic materials, known for their uniformity and strength, might offer favorable occlusal stability and minimize adverse impacts on the TMJ [22]. Conversely, the layered construction of hybrid materials may require meticulous occlusal adjustments to ensure harmonious TMJ function, especially in cases with existing TMJ issues.
Occlusal considerations and treatment planning: A thorough understanding of the patient’s TMJ status is essential for comprehensive treatment planning in full-arch restorations. Accurate diagnostic methods, including imaging and occlusal analysis, aid in identifying TMJ-related issues and guide appropriate treatment strategies [23]. Occlusal adjustments and splint therapies might be necessary to manage TMJ-related symptoms and establish a stable occlusal relationship.
Clinical management strategies: Careful consideration of occlusal factors and occlusal equilibration techniques can aid in minimizing TMJ-related complications in full-arch restorations [24]. Occlusal splints or other adjunctive therapies might be utilized to stabilize the occlusion and alleviate TMJ-related discomfort during the restoration process.
Long-term implications: The impact of TMJ issues on full-arch restorations extends to their long-term success. Any occlusal discrepancies or untreated TMJ disorders may lead to discomfort, compromised function, and potential restoration failure over time. Regular follow-ups and monitoring of TMJ health are imperative for ensuring the stability and longevity of restorations.

The consideration of TMJ health is crucial in the planning and execution of full-arch restorations. Material selection, meticulous treatment planning, and clinical management strategies tailored to the patient’s TMJ status are pivotal for minimizing TMJ-related complications and ensuring the long-term success of restorations (Table 3).

Factors	Monolithic materials	Hybrid materials
Strength and Uniformity	Monolithic materials, such as zirconia, offer uniformity and high strength, potentially contributing to improved occlusal stability and reduced impact on TMJ health.	Hybrid materials might require meticulous adjustments due to their layered construction, potentially posing challenges in achieving optimal occlusal harmony in cases with existing TMJ issues.
Occlusal Adaptation	The homogeneous structure of monolithic materials may aid in establishing stable occlusal relationships, potentially minimizing occlusal discrepancies related to TMJ disorders.	Layered construction in hybrid materials could necessitate extensive occlusal adjustments to achieve harmonious occlusion, especially in cases with TMJ issues, potentially posing challenges in achieving stable occlusal relationships.
Clinical Management	Monolithic materials might offer ease in occlusal adjustments and clinical adaptability, potentially aiding in managing occlusal discrepancies associated with TMJ disorders.	Clinical management with hybrid materials may require meticulous handling and comprehensive occlusal analysis to establish stable occlusal relationships in patients with TMJ issues.

Table 3.

Comparison: monolithic vs. hybrid materials in relation to TMJ issues.

In summary, while monolithic materials like zirconia exhibit uniformity and strength, potentially contributing to improved occlusal stability and reduced impact on TMJ health, they might offer more straightforward clinical management in cases with existing TMJ issues. Conversely, hybrid materials, despite their esthetic advantages, may pose challenges in achieving optimal occlusal harmony and require meticulous adjustments, especially in patients with TMJ disorders.

5.5 Impact on opposing teeth

Influence of material type: The choice of materials for full-arch restorations can significantly influence the impact on opposing dentition. Monolithic materials, known for their strength and hardness, have the potential to distribute occlusal forces evenly, minimizing wear on opposing natural teeth [25]. These materials, such as zirconia or high-strength ceramics, can maintain occlusal stability, reducing the likelihood of excessive wear or damage to opposing dentition.
In contrast, hybrid materials, characterized by their layered construction, might present challenges in replicating the hardness and wear resistance comparable to natural teeth or monolithic restorations [25]. The variations in material properties between layers in hybrid restorations may potentially result in increased wear on opposing teeth due to differential hardness or surface characteristics.
Clinical observations and considerations: Clinical observations suggest that monolithic restorations exhibit favorable wear properties, providing minimal abrasiveness to opposing dentition [26]. The hardness and structural integrity of monolithic materials contribute to reduced wear rates on natural teeth when compared to hybrid restorations.
However, hybrid materials, particularly those with softer veneering layers or varying compositions, might exhibit increased wear characteristics, potentially causing accelerated wear on opposing natural teeth [26]. The differential wear properties between hybrid layers and natural dentition could lead to uneven wear patterns and potentially compromise the longevity of the restoration.
Long-term implications: Considering the long-term implications, monolithic materials tend to offer a more favorable impact on opposing dentition, exhibiting minimal wear on natural teeth, and maintaining occlusal harmony. On the contrary, the potential for increased wear with hybrid materials might require careful monitoring and regular assessment to manage any accelerated wear issues on opposing dentition [27].

The choice between monolithic and hybrid materials for full-arch restorations holds significance in their impact on opposing dentition. Monolithic materials, with their superior hardness and wear characteristics, tend to have a more favorable impact, minimizing wear on natural teeth. Conversely, hybrid materials, due to their variable composition and potential differences in hardness, might present challenges, potentially leading to accelerated wear on opposing dentition.

Monolithic materials, with their inherent hardness and durability like natural teeth, tend to have a more favorable impact on opposing dentition, exhibiting minimal wear over time. Conversely, hybrid materials, with potential differences in hardness between layers, may present challenges in mimicking the wear characteristics of natural teeth, potentially causing accelerated wear on opposing dentition.

The debate between monolithic and hybrid materials concerning the impact on opposing teeth in full-arch restorations highlights the superiority of monolithic materials in minimizing wear on natural dentition. Their inherent hardness and wear resistance qualities offer sustained occlusal harmony, contrasting with potential challenges presented by hybrid materials, especially in replicating natural dentition hardness and wear characteristics.

5.6 Patient age considerations

Definition and importance: Patient age plays a pivotal role in the selection of materials for full-arch restorations. Monolithic materials, like zirconia or high-strength ceramics, are characterized by exceptional hardness and wear resistance, qualities advantageous for older patients prone to increased occlusal wear or age-related changes. Hybrid materials, while offering esthetic flexibility, may present challenges in replicating natural dentition hardness uniformly across layers, potentially affecting long-term performance in older individuals.
Influence on material selection: Monolithic materials, due to their robustness and durability, emerge as favorable options for older patients or those experiencing age-related occlusal changes. The inherent hardness and wear resistance of monolithic materials offers enhanced longevity and reduced wear on restorations, accommodating increased occlusal forces associated with aging. In contrast, the variable properties between layers in hybrid restorations might pose challenges in mimicking natural dentition hardness in older patients, potentially impacting long-term performance [28].
Diagnostic assessment: Accurate evaluation of patient age and associated factors is essential in material selection for full-arch restorations. Monolithic materials demonstrate advantages in sustaining durability and resisting wear in older patients with potentially compromised dentition due to age-related factors. Conversely, hybrid materials might necessitate comprehensive diagnostic assessments to gauge their suitability in managing age-related occlusal changes and potential wear discrepancies [28].
Clinical implications: Monolithic materials provide reliable solutions for older patients, ensuring longevity and reduced wear on restorations, aligning well with age-related occlusal demand. However, hybrid materials might require meticulous clinical management and closer monitoring, especially concerning potential wear discrepancies and challenges in replicating natural dentition hardness, particularly in older individuals [28].

In evaluating patient age considerations for full-arch restorations, monolithic materials demonstrate superior durability and wear resistance, making them more suitable for older individuals with increased occlusal demands and age-related changes. On the contrary, while offering esthetic advantages, the variable composition of hybrid materials might pose challenges in managing age-related occlusal changes and wear discrepancies in older patients.

Considering patient age as a crucial factor, the selection of monolithic materials for full-arch restorations emerges as a preferred option for older individuals. The robustness and durability of monolithic materials offer enhanced longevity and reduced wear, addressing the challenges associated with age-related occlusal changes, compared to potential concerns posed by hybrid materials.

6. Strengths and weaknesses of hybrid and monolithic materials

6.1 Hybrid materials

Strengths: Hybrid materials excel in esthetic versatility, allowing for detailed customization to achieve natural-looking results. They also offer repairability, enabling chairside adjustments for minor issues.
Weaknesses: The fabrication process can be complex, demanding skilled technicians and potentially extending the timeline. Maintenance challenges may arise due to the layered nature of these materials.

6.2 Monolithic materials

Strengths: Monolithic materials boast high durability throughout, offering resistance to fractures and chipping. The simplified fabrication process is quicker and more straightforward than that of hybrid materials.
Weaknesses: Esthetic limitations may pose challenges in achieving intricate appearance details. Chairside adjustments can be more complex due to the material’s hardness.

7. Biocompatibility and tissue response

Biocompatibility and tissue response to different materials form a critical aspect of full-arch implant restorations. Hybrid materials, with their combination of substructure and layered components, interact dynamically with the oral environment. Monolithic materials, being uniform throughout, offer a different interaction profile. Understanding the biocompatibility of each material ensures long-term integration and minimizes the risk of adverse reactions within the oral cavity.

In the context of hybrid and monolithic restorations, considerations of biocompatibility extend beyond material composition to encompass how each restoration type interacts with surrounding tissues. The response of the gingiva, potential inflammatory reactions, and overall tissue health are crucial factors in the decision-making process. Clinicians must weigh these aspects carefully to ensure the selected material promotes not only functional success but also a healthy and harmonious relationship with the oral environment.

8. Case studies

Hybrid materials, characterized by layered structures as can be observed in Table 4, present a dynamic interplay between opacity changes and hygiene considerations. Over time, these materials may undergo opacity alterations due to factors like wear, staining, or modifications in composition. This increased porosity creates microscopic spaces, raising concerns about bacterial accumulation. In contrast, monolithic materials, exemplified also in Table 4, embody stability and resilience in the face of hygiene variations. Their opacity remains consistently stable over time, providing a reliable esthetic profile.

Case	Material type	Pros	Cons
Prosthetic space	Hybrid	Offers layering for esthetic customization Potential for easier repairs and adjustments	Requires more space due to layered construction Susceptible to delamination or chipping
	Monolithic	Conservative in-space requirements Superior durability and resistance to fractures	Limited esthetic versatility Challenging repairs or adjustments
Esthetics	Hybrid	Enhanced esthetic adaptability and lifelike translucency Natural appearance like natural dentition	Potential for color discrepancies between layers Proneness to wear variations over time
	Monolithic	Uniform color and translucency resembling natural teeth Robustness and resistance to wear	Limited customization in esthetics Challenges in achieving lifelike translucency
Bruxism	Hybrid	Potential for absorbing forces due to layered composition Esthetic layer provides chipping resistance	Susceptible to wear discrepancies between layers Possible delamination in high-stress situations
	Monolithic	High resistance to fractures and wear Superior durability under occlusal forces	Limited ability to absorb forces like hybrid materials Challenging repairs in case of damage
TMJ Issues	Hybrid	Layered construction offers potential shock absorption Esthetic layers enhance restoration appearance	Possibility of wear differences between layers Risk of chipping or delamination
	Monolithic	Superior strength and resilience against occlusal forces Reduced risk of wear discrepancies	Limited shock-absorbing capability compared to hybrids Potential challenges in achieving optimal esthetics
Impact on Opposing Teeth	Hybrid	Esthetic layer potentially minimizes wear on opposing teeth Potential for shock absorption	Varying wear characteristics between layers Risk of chipping or delamination
	Monolithic	Consistent wear properties resembling natural dentition Reduced wear on opposing teeth	Limited shock absorption compared to hybrid materials Challenges in esthetics customization
Patient Age Considerations	Hybrid	Esthetic customization for age-related changes Layered construction offers potential wear adaptation	Variable wear characteristics between layers Susceptibility to wear discrepancies in aged dentition
	Monolithic	Superior durability and wear resistance in aged dentition Consistent wear properties	Limited customization for age-related changes Potential challenges in managing wear discrepancies

Table 4.

Comparison: monolithic vs. hybrid materials – conclusions.

The consideration of Vertical Occlusion Dimension (DVO) is pivotal in the success of full-arch restorations. DVO encompasses the dynamic interplay of occlusal forces during various functional movements, including chewing and speech. The choice of materials must align with the dynamic nature of occlusion, ensuring that the restoration can withstand and distribute forces harmoniously. This consideration is particularly crucial for full-arch restorations, where occlusal demands are distributed across multiple teeth. The selection of materials for full-arch restorations involves a careful balance of various factors.

Each material option, whether traditional such as porcelain-fused-to-metal (PFM) or contemporary like zirconia or lithium disilicate, comes with its unique set of characteristics. Evaluating the patient’s specific needs, occlusal scheme, and esthetic preferences becomes imperative. Recent advancements in materials, such as high-performance polymers and bioactive composites, offer promising alternatives, introducing a new dimension to material selection (Figure 12).

Figure 12.
Two case studies with full-arch restorations on both maxillary and mandible, from the first meeting until the last recall.

A trade-off analysis between materials is inherent in the decision-making process. Traditional materials may provide durability but could pose challenges in achieving optimal esthetics. On the other hand, newer materials with enhanced esthetics might require careful consideration of their mechanical properties and long-term performance. Finding the delicate balance between esthetics, resistance to wear, and overall longevity is a central theme in the trade-off discussions, necessitating a personalized approach for each patient. The discussion underscores the importance of individualized treatment planning for full-arch restorations. Tailoring the material selection to each patient’s unique requirements, considering their occlusal dynamics, esthetic expectations, and potential lifestyle factors, is paramount. This approach ensures that the chosen materials not only meet immediate needs but also contribute to the long-term success and satisfaction of the restoration.

The choice of Zirconia restorations glued to a titanium milled bar represents a contemporary approach, combining the strength of Zirconia with the lightweight and biocompatibility of titanium. This material pairing aims to offer a harmonious blend of durability, resistance to corrosion, and biocompatibility. The selection hinges on achieving a balance between the mechanical properties of Zirconia and the favorable characteristics of titanium. This technique facilitates resistant restoration for patients with DVO bigger than 14 mm. A monolithic restoration would be too heavy, and a hybrid restoration such as PFMs is not reliable on such medical cases because there it is a lack of resistance.

9. Future trends and innovations

9.1 Emerging materials and technologies

The ever-evolving landscape of dental materials and technologies continues to drive innovation in full-arch restorations. Emerging materials, such as high-performance polymers, nano-ceramics, and bioactive composites, are gaining traction, aiming to combine strength, esthetics, and biocompatibility. These materials showcase improved mechanical properties and enhanced esthetic possibilities, offering promising alternatives in the quest for optimal restorative solutions.

9.2 Digital advancements and CAD/CAM integration

The advent of digital dentistry has revolutionized the fabrication process for full-arch restorations. Advanced CAD/CAM technologies streamline workflow, enabling precise digital impressions, design, and manufacturing of restorations. Integration with intraoral scanners, 3D printing, and virtual treatment planning optimizes accuracy, efficiency, and patient satisfaction. Future advancements are anticipated to further refine these technologies, enhancing precision and expanding material options.

9.2.1 Biomimetic and bioactive approaches

Innovations inspired by biomimicry and bioactivity are shaping the future of restorative materials [29, 30]. Biomimetic designs aim to replicate natural tooth structure and function, fostering enhanced integration and functionality within the oral environment. Bioactive materials, capable of stimulating tissue regeneration or remineralization, hold promise in fostering improved interactions at the restoration-to-tooth interface, potentially enhancing longevity and biocompatibility.

9.2.2 Personalized and regenerative dentistry

The shift toward personalized dentistry encompasses tailored treatment approaches based on individual patient characteristics [31]. Regenerative therapies, including tissue engineering and biologically driven approaches, are being explored to restore lost or damaged tissues around dental implants. This personalized approach aims to optimize treatment outcomes, promoting natural tissue regeneration and improving long-term success rates.

9.2.3 Implications for clinical practice

The integration of these evolving trends and innovations into clinical practice holds immense potential. Clinicians embracing these advancements are poised to offer enhanced treatment options, improved patient experiences, and long-lasting restorations. Continual education and adaptation to emerging technologies will be instrumental in leveraging these innovations to their full potential, ultimately benefiting both clinicians and patients.

10. Conclusion

The journey through the realm of full-arch restorations unveils a nuanced debate surrounding the selection of materials, notably between monolithic and hybrid compositions. These deliberations encompass a spectrum of clinical, functional, and esthetic considerations, shaping the paradigm of modern restorative dentistry.

Material landscape evolution: The historical trajectory illustrates a progression in materials from conventional options to contemporary choices. This evolution has pivoted toward the dichotomy of monolithic and hybrid materials, each offering distinct advantages and challenges in the landscape of full-arch restorations.

Clinical considerations and material selection: Clinical decision making is pivotal, influenced by multifaceted factors such as prosthetic space, occlusal dynamics, bruxism, TMJ status, opposing dentition, and patient age. Monolithic materials, epitomized by their robustness and wear resistance, are favored in scenarios necessitating durability and reduced wear on restorations, notably in older patients or those with higher occlusal demands. Hybrid materials, while presenting esthetic adaptability, may require meticulous management and closer scrutiny, especially concerning replicating natural dentition characteristics and managing occlusal challenges.

Strengths and weaknesses: Monolithic materials shine in their exceptional hardness, durability, and ability to mirror natural dentition wear characteristics, ensuring long-term stability and reduced wear on opposing teeth. Conversely, hybrid materials offer versatility in esthetics but might introduce challenges in uniform wear properties and longevity due to the variable composition across layers.

Esthetics, biocompatibility, and future implications: Esthetic considerations, biocompatibility, and ongoing technological advancements play pivotal roles in shaping the trajectory of material choices. Hybrid materials, with their esthetic potential, offer customizable options, while advancements aim to bridge the gap between strength and esthetics.

Patient-centric approach: The chapter underscores the paramount importance of an individualized patient-centric approach in material selection. Tailoring choices based on patient-specific factors ensures optimal outcomes, emphasizing the necessity of precise diagnosis, treatment planning, and meticulous execution.

In essence, while the debate between monolithic and hybrid materials persists, the selection must align with the specific clinical scenario and patient needs. Monolithic materials dominate in offering durability and reduced wear, especially in aged or occlusal-demanding patients, while hybrid materials present esthetic versatility but demand careful clinical handling. The future promises continued innovation, aiming to amalgamate strength, esthetics, and clinical adaptability, shaping the trajectory of full-arch restorations in restorative dentistry.

Munetaka Sugihashi

Chapters authored

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