Abstract

Introduction:
Minimally invasive posterior restorations (MIPRs) aim to preserve tooth structure while ensuring optimal function and esthetics. Adhesively bonded restorations such as onlays, overlays, and endocrowns provide conservative alternatives to full crowns. The clinical performance of these restorations depends largely on appropriate material selection, preparation design, and bonding procedures.

Methods:
This work presents four clinical situations illustrating different applications of MIPRs: a lithium disilicate endocrown, a zirconia endocrown, a disilicate onlay, and a zirconia overlay. Each case was analyzed regarding indication, preparation strategy, CAD/CAM fabrication, and adhesive luting protocol. Special attention was given to margin management, Immediate Dentin Sealing (IDS), and occlusal integration.

Results:
Clinical observations revealed satisfactory marginal adaptation, occlusal harmony, and esthetic integration in all four cases. Lithium disilicate restorations provided excellent translucency and enamel bonding potential, while zirconia offered enhanced fracture resistance in high-stress situations. IDS improved bonding reliability and reduced postoperative sensitivity. No complications were observed during follow-up.

Conclusions:
The clinical outcomes from these four cases support the reliability of MIPRs as conservative and durable treatment options for posterior teeth. The choice between disilicate and zirconia should be guided by the amount of residual tooth structure, esthetic expectations, and functional demands. Mastery of adhesive techniques remains essential for long-term success.

Background: Acrylic bone cement is widely used in orthopedics and dentistry for primary bone fixation. However, its limited mechanical strength and poor biological interface pose clinical challenges. To enhance their properties, carbon nanotubes (CNTs) and silver nanoparticles (Ag) have been explored. CNTs are known to reinforce polymers, while Ag nanoparticles provide antimicrobial benefits. Combining both may yield a synergistic effect, improving mechanical strength and antibacterial performance. Objective: This study evaluates the effect of incorporating 0.05 wt% silver-doped carbon nanotubes (Ag-doped CNTs) into acrylic bone cement. Key properties assessed include compressive strength, flexural strength, surface microhardness, wettability, and antibacterial activity against Staphylococcus aureus. Methods: A control group was prepared using traditional acrylic powder mixed with monomer liquid. In the modified group, 0.05 wt% Ag-doped CNTs were added to the acrylic powder before mixing. Compressive strength, flexural strength, surface microhardness, and wettability were tested. Antibacterial activity was evaluated using an agar diffusion test against S. aureus to test the inhibition zone. Independent sample t-tests (p < 0.05) were used to compare results between groups. Results: The modified acrylic cement exhibited significantly higher compressive strength (91 MPa), flexural strength (73 MPa), surface microhardness (39.1 VHN), and improved wettability (contact angle: 92.2°) compared to the control group, which recorded values of 72.3 MPa, 54.3 MPa, 21.1 VHN, and 107.9°, respectively. Additionally, the modified cement demonstrated a larger inhibition zone diameter against S. aureus (12.6 mm) than the control (9.1 mm) (P < 0.05). Conclusion: Incorporating 0.05 wt% Ag-doped CNTs into acrylic bone cement significantly improves its mechanical and antibacterial properties. This modification holds strong potential for clinical applications in both orthopedics and dentistry, offering enhanced strength, better surface characteristics, and effective bacterial inhibition compared to traditional formulations.

Printed digital and conventional complete dentures require appropriate hygiene materials and methods to prevent the formation of biofilm, tartar, stains, inflammation, and odor. However, some hygiene materials can affect resin properties, such as surface roughness, which, when increased, can favor biofilm adhesion and development. In the literature, it has been reported that roughness values ≤ 0.2 µm are considered clinically acceptable; however, studies evaluating the effects of hygiene protocols on the roughness of printed resins are scarce. So, this study compared the roughness of 3D printed resins for denture bases (3DB) and teeth (3DT) to conventional resins for base (CB) and teeth (CT), after hygiene protocol use. Ten specimens of each material were subjected to brushing and immersion in water (EA, control), 0.25% sodium hypochlorite (EHS), or 0.15% triclosan (ET). Roughness was measured after obtaining the specimens (T0) and after simulating daily 6-minute brushing and daily 20-minute immersion for 1 (T1) and 3 years (T3), using a confocal laser microscope (µm). Data were analyzed using Generalized Estimating Equations (GEEs) and Wald test with Bonferroni adjustment (α=0.05). Roughness was influenced by the following interaction: resin × hygiene protocol × time (p=0.012). In T1, the average roughness (Sa - µm) of the 3DB (EA: 0.239; EHS: 0.258; and ET: 0.265) and 3DT (EA: 0.211; EHS: 0.202; ET: 0.248) resins was considered unacceptable. In T3, the roughness of the 3DB (EA: 0.183; EHS: 0.161; ET: 0.199) and 3DI (EA: 0.181; EHS: 0.173; ET: 0.188) resins decreased, possibly due to the removal of superficial layers of resin through brushing, exposing inner layers with less roughness. Conventional resin roughness remains within acceptable limits regardless of hygiene protocol. Compared to conventional resins, printing resins should be indicated for short-term situations, when associated with the proposed hygiene protocols. Hygiene protocols can be recommended for both conventional resins during the periods studied.

Introduction: The accuracy and efficiency of dental model fabrication has experienced significant progress in recent years. However, environmental concerns, such as the use of petrochemical by-products, overproduction of plastic and waste management, have redesigned new materials that can lessen these environmental challenges and contribute to a better ecological transition. Objective: To analyze cutting-edge technology in 3D printing techniques applied to the fabrication of dental models, with a particular focus on sustainable practices. Methods: This systematic review was conducted according to PRISMA guidelines. A comprehensive literature search was conducted using the electronic academic databases PubMed, Web of Science, and Scopus. The search strategy incorporated specific keywords and MeSH terms relevant to sustainable dental 3D printing. Scientific articles reviewed and published between 2020 and 2025 were considered. Studies written in English, German and Spanish were included in the selection process. Results: A total of five in vitro studies met the inclusion criteria and contain sufficient information for this review. All studies are in vitro and are peer reviewed articles from the years 2023-2024. The materials investigated in these studies were polylactic acid (PLA), recycled PLA, recycled resins and soy-based resins. The studies employed either fused filament fabrication (FFF) or vat polymerization technology (VAT) as the main 3D printing techniques. Each study addressed sustainability as a central theme. Conclusion: The results of this systematic review show the potential of 3D dental models in the adoption of more sustainable materials such as biodegradable and/or recyclable polymers but this approach is relatively novel in the dental sector. The performance of these innovative materials has improved in terms of dimensional accuracy, efficiency and clinical application. Materials such as polylactic acid (PLA) and fused filament fabrication (FFF) are set to play a key role in the advancement of environmentally friendly dental manufacturing.

Introduction: Three-dimensional printed dentures have poor thermal and thermomechanical properties, which hinder their clinical applications. Previous denture nanocomposite studies focused on mechanical and physical properties. In this study, the impacts of TiO₂ NT addition to 3D-printed denture based on some thermal properties were studied for the first time.

Methodology: Digitally formed specimens (DLP Asiga 3D printer) for 1) Hot-Disc (thermal conductivity (W/km), diffusivity (mm²/s), volumetric heat capacity (MJ/m³K) tests). 2)Thermomechanical-analyzer (TMA) (coefficient of thermal expansion (10^‒6/K), thermal strain (%) and elastic modulus (N/mm²)). 3) Glass transition temperature (Tg) (⁰C) (by DSC, DTA and TMA). 4) Thermal stability (weight%). 5) Degree of conversion (DC%) by ATR-FTIR. Following ISO (22007, 11359, 11357, 11358 and 10640), respectively. TiO₂ NTs (Diameter=30-70nm and length=2-4µm) were added at 1.0 wt.% and 2.0 wt.%. Ultrasonication (3 minutes) for nanotube dispersion, magnetic stirrer (8 hours) for TiO₂ NTs/ 3D liquid resin mixing. Printing settings: slice thickness=50µm, heater temperature=30°C, wavelength=385nm, 90-degree printing orientation and (65 watts/30 minutes) post-polymerization curing. The effective sample size was 30 specimens for each test (10 specimens for each group), which was calculated using G power (power=85%, alpha error=.05, effect size=0.25, groups=3, measurements=5 (30°C, 40°C,50°C,60°C,70°C)). Data analysis via SPSS and Prism 8.4. Shapiro–Wilk (normality), Levene (homogeneity), ANOVA and post-hoc tests were utilized. Significance level at α=.05.

Results: Increasing TiO₂ NT concentration improved all the tested thermal and thermomechanical properties. However, Tg increased for the 1.0 wt.% group and decreased for the 2.0 wt.% group. The Tg decreased due to the aggregation of the nanofiller and functioned as a plasticizer or impurity, thus increasing the mobility of the chains. The DC% increased in both 1.0 wt.% and 2.0 wt.% groups, although this increase was statistically non-significant with a P value of 0.9801).

Potential clinical impact: improvement in thermal perception. A marginal deterioration reduction between different denture parts interface, and improved ability to withstand wide range of intra-oral temperatures during eating.