Search Results (647)

This study evaluated the effect of sports and energy drinks on the surface roughness of three commonly used restorative dental materials: resin-based composites (RBCs), resin-modified glass ionomer cements (RMGICs), and conventional glass ionomer cements (GICs). Sixty-three A2-shade specimens of each material were fabricated, stored in distilled water for 24 h, and then immersed in six commercially available beverages or distilled water (control) for 6, 30, or 60 h. Surface roughness was assessed after each immersion period using contact profilometry, and the effects of material type, immersion medium, and exposure time were compared. Surface roughness increased with longer immersion times for all materials, although the magnitude of change varied significantly among material types. RBCs showed the greatest resistance to surface degradation, whereas RMGICs and particularly GICs exhibited progressively higher roughness values over time. Beverages generally produced greater surface roughness than distilled water, with sugar-containing formulations showing higher roughness values than their sugar-free counterparts. Prolonged exposure to sports and energy drinks may adversely affect the surface integrity of restorative materials. Resin-based composites demonstrated the highest resistance to roughness changes, whereas glass ionomer cements were the most susceptible. Increased surface roughness may contribute to plaque accumulation, staining, and material wear, potentially compromising the long-term clinical performance of restorations. Full article

The study aimed to develop and preliminarily characterize experimental resin-based dental composites (RBCs). In addition to the composites, didodecyldimethylammonium bromide (DDAB) was used as a biocide in various concentrations (0–3 wt%). Hardness (HV), flexural strength (FS), and modulus of elasticity, as well as diametral tensile strength (DTS) of composites, were examined. Additionally, shrinkage stress, surface free energy (SFE), water sorption (Wsp), and solubility (Wsl) were determined. Cytometric analysis, including biocidal surface testing and susceptibility to colonization by Streptococcus mutans, Escherichia coli, and Candida albicans, assessed antibacterial activity. The HV of RBCs varied from 27.2 ± 1.5 to 31.5 ± 1.8 depending on DDAB amount, FS—67.0 ± 16.1 MPa for control composite and 79.2 ± 14.5 MPa for modified composite. All DTS values exceed 24 MPa. Shrinkage stress is highest for the composite with 0.25 wt% DDAB—18.5 ± 1.9 MPa—and lowest for the composite with 1 wt% DDAB—15.0 ± 2.5 MPa. Wsp is lowest in the control group (37.19 ± 1.69 µg/mm³) and highest for 1 wt% modifier (42.11 ± 2.75 µg/mm³). Wsl was at its lowest in control group (1.98 ± 1.58 µg/mm³), and highest for modification with 1 wt% (3.91 ± 1.74 µg/mm³). For RBCs modified with 3 wt% DDAB after 60 min, an increase in dead cells is observed: 51% for Escherichia coli, 71% for Streptococcus mutans, and 24% for Candida albicans. Preliminary results show that DDAB effectively reduced the presence of the tested pathogens and contraction stress; however, at certain concentrations it negatively influences hardness and water sorption of composites. The presented findings highlight both the potential and the limitations of DDAB-modified RBCs and underline the need for further studies, including cytotoxicity and genotoxicity assessments, release analyses and evaluation of composites’ ageing behavior. Full article

The objective of this study was to evaluate the antioxidant and antibacterial profiles of Picea orientalis (Oriental spruce) resin extracts collected from three distinct geographical sites (Artvin, Borçka, and Çaykara) within the Eastern Black Sea region of Türkiye. Additionally, it aimed to assess the viability of these extracts as natural antibacterial agents against cariogenic pathogens and to determine their subsequent effect on dental bond strength performance. Quantitative phytochemical analysis of the ethanolic extracts included the determination of total phenolic content, coupled with individual phenolic profiling by HPLC-PDA. The antioxidant potential was assessed through DPPH and FRAP assays. Additionally, the antibacterial activity against a panel of oral and systemic pathogens was evaluated using agar well diffusion. Furthermore, to evaluate mechanical performance, composite bond strengths were tested on 180 dentin specimens using both self-etch and etch-and-rinse adhesive strategies, following cavity pre-treatment with a control, chlorhexidine, or the resin extracts. The results revealed that the resin from the Artvin region exhibited the highest phenolic content, characterized by an abundance of trans-cinnamic, caffeic, and ferulic acids, which correlated with their superior antioxidant capacity. Furthermore, while the extracts demonstrated potent inhibitory effects against Staphylococcus aureus, their antibacterial activity against Streptococcus mutans was found to be comparatively moderate. In bond strength evaluations, the non-aged control group exhibited the highest values (p = 0.000); however, no statistically significant difference was observed between the chlorhexidine and resin extract groups (p > 0.05). Consequently, the phenolic-rich P. orientalis resin represents a promising natural antibacterial alternative for dental applications. Full article

Directing a stream of air across the tooth when light curing resin-based composites (RBCs) may affect their degree of conversion (DC), maximum rate of polymerization (RP_max), and in vitro intrapulpal temperature. Methods: Filtek One Bulk Fill and VisCalor bulk were preheated according to the manufacturer’s instructions and used to fill a Class I cavity in a molar at 32 °C. A stream of air at either 15 or 30 psi was directed across the tooth from an air-water syringe positioned 1 cm from the buccal surface. The RBCs were light-cured for 20 s using the Bluephase N, and the DC and RP_max were determined from real-time FT-IR data. A T-type thermocouple positioned inside the pulp chamber recorded the temperature. DC and RP_max data were analyzed using one-way ANOVA, whereas temperature was analyzed using two-way ANOVA, followed by Tukey post hoc tests. Results: Directing a stream of air at the tooth produced no significant differences in the DC and RP_max. The temperature change (ΔT) decreased compared to when no air was delivered. No significant difference in ΔT was found between the two air pressures. Conclusions: Directing a stream of air across the tooth when the preheated RBC was inserted did not affect the polymerization kinetics. The air stream reduced the temperature rise inside the pulp chamber as the RBC was light-cured. Clinical Significance: Directing a stream of air across the tooth at either 15 psi or 30 psi during light curing is an easy method to reduce the temperature increase inside the pulp chamber without affecting the polymerization kinetics of the evaluated preheated RBCs in this in vitro model. Full article

Background and Objectives: Long-standing contact between oral mucosa and restorative materials may be associated with adaptive epithelial and stromal remodeling. This study evaluated non-dysplastic epithelial plasticity in the oral mucosa adjacent to long-term restorative materials. Materials and Methods: This retrospective study included 150 formalin-fixed, paraffin-embedded oral mucosal specimens divided into five groups: control, dental amalgam, methacrylate-based resin composite, clinically documented all-ceramic restorations, and metallic/metal–ceramic restorations (n = 30 each). Exposed cases had documented mucosal adjacency or repetitive contact with a dominant restorative material for at least 5 years. Histopathological parameters, CK19, Ki67, p53, and COX-2 expression were assessed, and MAERS was calculated. Statistical significance was set at p < 0.05. Results: MAERS differed significantly among groups (p < 0.001), with the highest mean values in metallic/metal–ceramic specimens (10.3 ± 2.4) and dental amalgam specimens (9.7 ± 2.1), intermediate values in resin composite specimens (7.1 ± 1.8), and the lowest values in all-ceramic (5.0 ± 1.4) and control specimens (4.8 ± 1.3). Suprabasal CK19 redistribution was observed in 22/30 metallic/metal–ceramic specimens (73.3%) and 20/30 amalgam specimens (66.7%), elevated Ki67 expression in 22/30 (73.3%) and 19/30 (63.3%), and moderate-to-strong COX-2 expression in 21/30 (70.0%) and 19/30 (63.3%), respectively. p53 expression was heterogeneous and did not show dominant, strong, or diffuse overexpression. Conclusions: Metallic/metal–ceramic restorations showed the highest remodeling burden, dental amalgam showed a similarly high profile, resin composite showed an intermediate profile, and all-ceramic-associated mucosa remained close to control specimens. These findings suggest material-dependent, inflammation-associated epithelial plasticity without evidence of epithelial dysplasia. Full article

The ongoing development of subtractive options for indirect restorations places clinicians in a position that requires adaptation, understanding and choosing of the most suitable option for the long-term survival of the restoration. Mechanical parameters represent important indicators of long-term success. Consequently, this research aimed to assess the impact of water sorption on the mechanical properties of two direct resin composites, Gradia Direct Anterior A2 and Filtek Z550 A2 and three CAD/CAM subtractively manufactured dental resin composites, Vita Enamic, Brilliant and Cerasmart. A total of one hundred specimens (50 control, 50 underwent this protocol: dehydration, immersion in distilled water for 30 days and then re-desiccation), standardized to the dimensions of 14 mm × 4 mm × 1.2 mm were subjected to three-point bending test (based on ISO 4049:2019 and ISO 6872:2015), in order to find out the flexural strength and the elastic modulus of the material at the breaking point. Then, the fractured sample surfaces were fractographical analyzed. Using the two-parameter Weibull approach, the Weibull modulus (m) and the characteristic strength (σ₀) were evaluated. In this investigation, the elastic modulus varied from 5.8 (Gradia Control) to 20.31 (Vita Degraded) GPa, with the upper limit close to the values of natural dentin (17.7–29.8 GPa). The values of flexural strength ranged from 174.47 (Brilliant Control) to 79.2 (Gradia Control), subtractively processed materials demonstrating higher flexural strength and elastic modulus values than the direct resin composites, which is related to their high inorganic filler content. All material groups, except for Gradia Control, had a flexural strength more than the 80 MPa minimum value needed to sustain masticatory force. The dehydration and hydration cycles did not have a statistically significant influence on the mechanical properties of the material. The fractographic analysis revealed fracture patterns and features associated with the microstructure, with the PICN category material being particularly notable. Weibull analysis revealed that the direct resin composite materials exhibited higher reliability, lower data scatter and CAD-CAM materials showed greater characteristic strength, with a notably high performance of the nano-hybrid direct resin composite. Full article

The radiopacity of adhesives is important for radiographic diagnosis and micro-computed tomography (micro-CT) evaluation of adhesive restorations. However, most universal adhesives lack sufficient radiopacity. This study examined the radiopacity and intracavity distribution of four universal adhesives—Scotchbond Universal Adhesive (SBU), Scotchbond Universal Plus Adhesive (SBP), Clearfil Universal Bond Quick ER (UBQ), and G-Premio Bond (GPB)—using a cylindrical cavity model. Cavities were prepared in bovine enamel–dentin blocks and scanned using micro-CT at 5.0 μm/voxel after cavity preparation, adhesive application, and resin composite filling (n = 3). The adhesive layer region was geometrically defined from sequential datasets and analyzed using actual 16-bit grayscale values. Grayscale values, adhesive layer thickness, and composite-filling-induced volume changes were evaluated by three-dimensional difference analysis. SBP showed a grayscale value equivalent to that of dentin, whereas SBU, UBQ, and GPB were statistically indistinguishable from air. Adhesive thickness increased from the lateral walls to the cavity floor, and reduced-density regions were observed in UBQ and GPB. Therefore, SBP was the only tested universal adhesive with dentin-equivalent radiopacity, enabling reliable micro-CT evaluation and reducing the risk of radiographic misdiagnosis. The proposed grayscale-based approach may support future non-destructive investigations of dental adhesive behavior. Full article

Tooth avulsion is one of the most severe dental injuries, and appropriate storage media are essential for preserving avulsed teeth before replantation. However, little is known about the effects of these media on the color stability of existing restorative materials. This in vitro study evaluated the color stability of a composite resin and a glass hybrid restorative material immersed in six storage media commonly recommended for avulsed teeth. A total of 120 disc-shaped specimens were prepared and allocated to dry environment, artificial saliva, tap water, cow’s milk, goat milk, and kefir groups. Color measurements were performed using the CIE L*a*b* system at baseline, 30 min, 1 h, 6 h, 12 h, and 24 h, and color change (ΔE) values were calculated. Data were analyzed using a linear mixed-effects model with restorative material, storage medium, and time as fixed effects and specimen ID as a random effect. Color change increased significantly over time in all groups (p < 0.001). Glass hybrid restorations exhibited significantly higher ΔE values than composite restorations across most storage media and time points (p < 0.001). Significant material–medium–time interactions were observed (p < 0.001), indicating that the effects of storage media varied according to restorative material and exposure duration. Dry storage conditions were generally associated with the highest color changes. Within the limitations of this study, the tested composite restorative material (G-ænial Posterior) demonstrated greater short-term color stability than the tested glass hybrid restorative material (EQUIA Forte HT) in the evaluated storage media. Full article

Background: Vitamin D deficiency rickets is a metabolic bone disorder caused by impaired calcium and phosphate homeostasis resulting from insufficient vitamin D. In children, severe vitamin D deficiency can disturb the mineralization of growing bones and teeth. Although the skeletal manifestations are well recognized, reports describing generalized developmental enamel defects affecting nearly all permanent teeth remain limited. Methods: A 6-year-9-month-old Japanese boy with a history of vitamin D deficiency rickets diagnosed at 2 years 5 months of age was referred to our department for evaluation of generalized discoloration and morphological abnormalities affecting multiple permanent teeth. Clinical, radiographic, and medical findings were reviewed. Results: Laboratory examination at diagnosis revealed severe vitamin D deficiency with elevated intact parathyroid hormone levels. Possible contributing factors included exclusive breastfeeding, delayed weaning, avoidance of fish and dairy products, and limited outdoor activity. Following oral alfacalcidol supplementation, skeletal and biochemical findings gradually normalized. However, clinical examination revealed generalized enamel hypoplasia affecting the permanent incisors and first molars, characterized by yellow-brown discoloration, rough enamel surfaces, morphological irregularities, and attrition, whereas the primary dentition showed no obvious abnormalities. Panoramic radiography demonstrated generalized crown malformation involving both erupted and unerupted permanent teeth, particularly the permanent incisors, first molars, and canines, while premolars and second molars were relatively unaffected. Based on the developmental timing of the affected teeth and the patient’s medical history, the enamel defects were considered to be associated with systemic mineralization disturbance during early childhood. Restorative treatment, including composite resin restorations and stainless steel crowns, was performed to improve aesthetics and occlusal function. Preventive surgical exposure followed by composite resin restoration was also performed for the permanent canines at the onset of eruption. Conclusions: Severe vitamin D deficiency during critical stages of tooth development may be associated with irreversible developmental enamel defects in the permanent dentition, even after apparent systemic recovery from rickets. Early dental assessment, long-term dental follow-up, and multidisciplinary management should be considered in children with a history of nutritional rickets. Full article

This study aimed to evaluate the influence of various 3D printing resins and post-processing cleaning protocols on the physical and mechanical characteristics of printed dental models. Specifically, the research compared the effects of water-based vs. isopropyl alcohol (IPA)-based cleaning on surface morphology, mass, color stability, and mechanical durability. The findings revealed that surface roughness and microstructure remained constant regardless of the solvent used, indicating that these properties are primarily driven by resin composition and curing protocols. However, specimens cleaned with water exhibited slightly higher mass values due to moisture retention or lower evaporation rates. Color stability remained unaffected by the post-processing method. Most notably, water-cleaned models demonstrated superior mechanical durability and structural integrity compared to those processed with IPA, which is often associated with micro-fractures and excessive dehydration. Full article

Additively manufactured definitive restorative materials have gained popularity recently. The current in vitro study evaluated the effects of surface treatment and thermocycling on the shear bond strength (SBS) between four 3D-printed definitive restorative materials and a self-adhesive resin cement (SARC). Disc-shaped specimens were fabricated from four printable materials: two composite materials, Crowntec (Crowntec) and CRS Composite (Custom Resin Solutions), and two ceramic-filled composites, Alias Dental Crown (Alias) and Permanent Crown (PC) (n = 12 per subgroup). Specimens were divided into four surface treatment subgroups: control, 9% hydrofluoric acid etching (HF), 50 µm aluminum oxide (Al₂O₃) airborne-particle abrasion (S50), and 110 µm Al₂O₃ airborne-particle abrasion (S110). SARC was applied using Teflon molds ($\varnothing 3 \times 3 \mathrm{m}\mathrm{m}$). After all specimens were stored in water at 37 °C for 24 h, half of the specimens were subjected to 10,000 thermocycles. Subsequently, SBS testing was performed for all specimens. Data were analyzed using Kruskal–Wallis and Mann–Whitney U tests (α = 0.05), and failure modes were classified microscopically. Before thermocycling, compared with control groups, HF significantly decreased SBS in Crowntec, whereas S110 significantly increased SBS in Alias (p < 0.05). After thermocycling, surface-treated CRS and Alias groups showed significantly higher SBS than controls (p < 0.05); Crowntec showed increased SBS after HF and S50, and Permanent Crown only after S50. No significant differences were found among control groups (p > 0.05). Surface-treated groups exhibited mainly mixed and cohesive failures. Surface treatments generally improved the SBS after thermocycling. Full article

Background: This study assessed the effect of solvent aging on Vickers microhardness (VHN) and fracture toughness (K_IC) of four resin composites: two high-strength flowable materials indicated for all cavity classes (GUF and CBF), a packable nanohybrid composite (XTE), and its flowable counterpart (XTEF). Methods: Disk specimens (n = 6 per group) were photocured and stored at 37 °C in distilled water or in a 75%/25% ethanol/water solution for 1 or 30 days. Vickers microhardness was recorded with a 300 g load applied for 15 s. Single-edge-notched beam (SENB) specimens (32 × 6 × 3 mm; n = 6 per group) were loaded in three-point bending for K_IC determination after 1 and 30 days of storage in water or ethanol/water. Data were analyzed by three-way ANOVA followed by Tukey’s post hoc test (α = 0.05). Results: At 1 day, the four composites separated into distinct VHN groups in the order XTE > GUF > CBF > XTEF (p ≤ 0.05). After 30 d, VHN decreased in all materials, with larger reductions in ethanol/water (17–30% relative to the 1 d water value) than in water alone (5–11%). At 1 day, K_IC values for XTE, GUF and CBF formed a single statistical group, all significantly higher than XTEF (p ≤ 0.05). Thirty-day water storage did not affect K_IC for any material (p > 0.05), whereas ethanol/water storage reduced K_IC by 21–26% in all four composites and produced four distinct material groups (p ≤ 0.05). Conclusions: The high-strength flowable composites showed greater hardness and toughness than a conventional flowable composite but did not match the mechanical performance of the highly filled packable composite. Ethanol/water aging markedly softened the composite surfaces and reduced fracture toughness, whereas prolonged water storage had a smaller effect on hardness and no measurable effect on K_IC. Full article

The polymerization shrinkage stress (SS), degree of conversion (DC), and Vickers hardness (HV) are properties that can affect the performance of resin-based composites (RBCs). This study tested four bulk-fill RBCs used in self-cured mode: Bulk EZ Plus (Zest Dental Solutions), Cention Forte (Ivoclar), Fill-Up! (Coltene), and Stela (SDI Limited), and two light-cured bulk-fill RBCs: Filtek One (Solventum) and SDR flow+ (Dentsply). The test specimens were 6 mm in diameter and 2 mm thick. Axial SS was measured in real time for 4000 s in the self-cured materials and for 1400 s after 10 s of light curing in the light-cured materials (n = 12 for self-cured RBCs; n = 11 for light-cured RBCs). To confirm that the RBCs were adequately polymerized, the DC was assessed using real-time ATR-FTIR spectroscopy, and the HV was measured on the top and bottom surfaces using a 300-gf load for 8 s (n = 5) after 24 h. The SS, DC, and HV differed significantly among the RBCs (p < 0.001). At 1400 s, Cention Forte developed the lowest stress (1.44 MPa), whereas Bulk EZ Plus and Fill-Up! produced the highest stress (3.77 MPa). The self-cured materials continued to develop measurable stress between 1400 s and 4000 s, while the light-cured RBCs had stabilized at 1400 s. Bulk EZ Plus and Stela produced the highest DC values, and Stela had the highest HV. Full article

Introduction: The goal of this study was to evaluate the influence of combined artificial aging protocols on the surface roughness and Vickers microhardness of bulk-fill resin composites, compared with a nanofilled composite used as a reference. Materials and Methods: A total of 120 cylindrical specimens were prepared from three bulk-fill composites (Tetric EvoCeram Bulk Fill, Filtek One Bulk Fill, Venus Bulk Fill) and one nanofilled composite (Filtek Supreme Ultra). Specimens were allocated into three aging conditions: mechanical wear (A), mechanical wear combined with pH-cycling (B), and mechanical wear combined with thermocycling (C). Surface roughness (Ra) and Vickers microhardness (VHN) were evaluated at two time points (T1: 120,000 cycles; T2: 240,000 cycles). Non-parametric statistical tests were applied (α = 0.05). Results: Aging protocols significantly influenced both Ra and VHN (p < 0.05). Overall, higher surface roughness and lower Vickers microhardness values were observed after cumulative aging, with material-dependent variations between T1 and T2. The greatest post-aging differences were observed under combined mechanical wear and pH-cycling (subgroup B), whereas mechanical wear alone showed the lowest changes. Filtek One Bulk Fill and Filtek Supreme Ultra showed more favorable post-aging Ra and VHN values, whereas Venus Bulk Fill showed less favorable post-aging surface properties. No significant correlation was found between Ra and VHN (rho = −0.009; p = 0.958). Conclusions: Combined aging conditions significantly affected the surface roughness and Vickers microhardness of resin composites, with the greatest post-aging differences observed under acidic challenges. Bulk-fill materials exhibit variable resistance depending on composition, emphasizing the importance of material selection for long-term clinical performance. Clinical relevance: Composite restorations exposed to combined mechanical and acidic challenges may show altered surface roughness and microhardness, highlighting the need for materials with enhanced resistance in high-risk oral environments. Full article

Background/Objectives: Image-based finite element analysis (FEA) is increasingly used in dental biomechanics; however, its reliability is often limited by insufficient experimental benchmarking and a lack of standardized workflows. This study aimed to quantitatively benchmark a Cone beam computed tomography-based (CBCT) finite element pipeline using experimentally measured strain in restored human molars. Methods: Extracted human mandibular molars were restored using a total-etch adhesive system and bulk-fill composite resin. Specimen-specific finite element models were generated from CBCT data using a standardized segmentation and meshing workflow. Numerical simulations were compared with experimentally measured strain obtained during mechanical loading using Digital Image Correlation. Agreement between numerical and experimental data was assessed using regression analysis, Bland–Altman analysis, and equivalence testing. Results: A total of 304 spatially clustered paired measurements nested within 16 specimens were analyzed. FEM predictions showed strong correlation with experimental data (r = 0.91–0.97; R² up to 0.937) and low relative error (~5–6%). The model systematically overestimated deformation by approximately 10–15%. Equivalence was confirmed within ±15% for dentin and composite, and within ±20% for enamel. Bland–Altman analysis revealed proportional bias and heteroscedasticity, particularly in dentin. Conclusions: The proposed CBCT-based finite element workflow demonstrates strong benchmarking agreement with experimental measurements and provides reproducible estimates of mechanical behavior within defined tolerance limits under controlled experimental conditions. Despite systematic overestimation, the model exhibits stable and reproducible behavior under controlled conditions. These findings support the use of experimentally benchmarked, image-based FEA workflows in dental biomechanical research. Full article