Search Results (143)

Background. Physicomechanical properties and clinical service of bulk-fill composites depend on their adequate polymerization and depth of cure. Some manufacturers claim that these composites can be adequately cured when used in bulks exceeding 4 mm. Objective. The aim of this study was to compare Vickers microhardness (VMH) and depth of cure (DOC) of six contemporary bulk-fill resin composites at depths of 4 mm and 6 mm. Material and methods. Six bulk-fill composites were evaluated in this study: 1. Tetric EvoCeram Bulk (Ivoclar Vivadent, Schaan, Liechtenstein), (TEC); 2. Filtek Bulk Fill Posterior (3M ESPE Dental Products Division, St. Paul, MN, USA), (FBF); 3. Filtek One Bulk Fill (3M ESPE Dental Products Division, St. Paul, MN, USA, (FOB); 4. SonicFill 2 (Kerr, Orange, CA, USA), (SF2); 5. Admira Fusion X-tra (Voco, GmbH, Cuxhaven, Germany), (AFX); 6. GrandioSO X-tra (Voco, GmbH, Cuxhaven, Germany), (GSX). The 18 specimens (3 of each composite) were prepared in split Teflon moulds of 4 mm diameter and 6 mm thickness. All composites were cured in standard mode for 20 s using LED LCU (D-Light Duo, RF-Pharmaceuticals Sarl, Geneva, Switzerland; 1200–1300 mW/cm). The VMH was measured using a digital Micro Hardness Tester Shimadzu (HMV-2T E, Shimadzu Corporation, Kyoto, Japan). A 50 g (0.5 N) load force was applied for 30 s. Each specimen was measured at five places selected by chance at each level (N = 15). The hardness ratio or DOC was calculated for all samples as the ratio of bottom and surface microhardness at levels of 4 and 6 mm. Data were analysed using one-way ANOVA and Tukey’s post hoc test. Results. Significant reduction in VMH was observed for all tested materials when comparing top surface and bottom (p < 0.01). The highest VMH was obtained for GSX and AFX, and the lowest for TEC. The results show that the degree of polymerization was adequate for all tested materials at a depth of 6 mm, since the hardness ratio exceeded 0.80 in all cases. The hardness ratio at 4 mm was high for all tested composites ranging from 0.91 for TEC to 0.98 for GSX. All composites showed adequate DOC at the bottom of the 6 mm bulk samples. However, the hardness ratio was the highest for Admira Fusion X-tra (0.96) and GrandioSO X-tra (0.97). Conclusions. All tested materials showed a significant decrease in microhardness from the top surface to the bottom. The DOC was adequate for all bulk-fill composites at a depth of 6 mm cured under standard mode for 20 s. All bulk-fill resin composites evaluated in this study can be used in bulk, up to 6 mm. Full article

Zirconia restoration debonding is one of the common issues in its dental applications because of its dense and chemically inert structure that is difficult to bond to. In this study, plasma treatment of zirconia was performed to improve its bond strength and longevity with dental resin cement. Sandblasted zirconia specimens were treated using argon cold atmospheric plasmas (CAPs), followed by applying a thin layer of 10-MDP primer, dental resin cement with light curing. Micro-shear bond strength (µSBS) test results showed that 300 s of CAP treatment significantly increased the initial µSBS to 38.3 ± 5.6 MPa as compared with the 21.6 ± 7.9 MPa without CAP treatment. After 30 days of storage in 37 °C deionized (DI) water, CAP-treated zirconia specimens had 191.2% higher bond strength than the bonded specimens without plasma treatment. After 1000 cycles of thermal cycling (TC) between 5 °C and 55 °C, the CAP-treated zirconia specimens gave 30.5% higher bond strength than the bonded specimens without plasma treatment. Surface–water contact angle measurements indicated that the zirconia surface became much more hydrophilic but showed rapid hydrophobic recovery within the first hour of CAP treatment, indicating the importance of promptly applying the primer after the plasma treatment. These findings suggest that the argon CAP technique is effective in the surface preparation of zirconia for enhancing bond strength and longevity with dental cement. Full article

Three-dimensional (3D) printing has emerged as a transformative technology in dental splint fabrication, offering significant advancements in customization, production speed, material efficiency, and patient comfort. This comprehensive review synthesizes the current literature on the clinical use, benefits, limitations, and future directions of 3D-printed dental splints across various disciplines, including prosthodontics, orthodontics, oral surgery, and restorative dentistry. Key 3D printing technologies such as stereolithography (SLA), digital light processing (DLP), and material jetting are discussed, along with the properties of contemporary photopolymer resins used in splint fabrication. Evidence indicates that while 3D-printed splints generally meet ISO standards for flexural strength and wear resistance, their mechanical properties are often 15–30% lower than those of heat-cured PMMA in head-to-head tests (flexural strength range 50–100 MPa vs. PMMA 100–130 MPa), and study-to-study variability is high. Some reports even show significantly reduced hardness and fatigue resistance in certain resins, underscoring material-specific heterogeneity. Clinical applications reviewed include occlusal stabilization for bruxism and temporomandibular disorders, surgical wafers for orthognathic procedures, orthodontic retainers, and endodontic guides. While current limitations include material aging, post-processing complexity, and variability in long-term outcomes, ongoing innovations—such as flexible resins, multi-material printing, and AI-driven design—hold promise for broader adoption. The review concludes with evidence-based clinical recommendations and identifies critical research gaps, particularly regarding long-term durability, pediatric applications, and quality control standards. This review supports the growing role of 3D printing as an efficient and versatile tool for delivering high-quality splint therapy in modern dental practice. Full article

Objectives: The increasing reliance on online platforms for dental education necessitates an assessment of the quality and reliability of available resources. This study aimed to evaluate YouTube videos as educational tools for Class IV resin composite restorations. Methods: The first 100 YouTube videos were screened, and 73 met the inclusion criteria. The videos were evaluated using the Video Information and Quality Index (VIQI) and specific content criteria derived from the dental literature. Videos with a score below the mean were identified as low-content videos. Results: No significant differences were noted between high- and low-content videos when examining the number of views, number of likes, duration, days since upload, viewing rate, interaction index, and number of subscribers (p > 0.05). The high-content videos demonstrated higher mean values compared with the low-content videos in flow (4.11 vs. 3.21; p < 0.0001), accuracy (4.07 vs. 3.07; p < 0.0001), quality (4 vs. 2.66; p < 0.0001), and precision (4.16 vs. 2.86; p < 0.0001). The overall VIQI score was significantly higher (p < 0.0001) for high-content videos (Mean 16.34; SD 2.46) compared with low-content videos (Mean 11.79; SD 2.96). For content score, high-content videos (Mean 9.36; SD 1.33) had a higher score (p < 0.0001) than low-content videos (Mean 4.90; SD 2.04). The key areas lacking sufficient coverage included occlusion, shade selection, and light curing techniques. Conclusions: While a significant portion of YouTube videos provided high-quality educational content, notable deficiencies were identified. This analysis serves as a call to action for both content creators and educational institutions to prioritize the accuracy and completeness of online dental education. Full article

Purpose: The aim of this in vitro study was to evaluate the influence of different models of commercially available portable dental radiometers on the measurement of light irradiance emitted by light-emitting diode (LED) photocuring units. Materials and Methods: Eight LED photocuring units, all emitting light in a single-wavelength spectrum, were tested. Light irradiance (mW/cm²) was measured using six portable dental radiometers: four digital models (D1–D4) and two analog models (A1, A2). Digital model D1 was used as the reference (control). All measurements were conducted under standardized conditions, and each LED–radiometer combination was tested in triplicate. Data were analyzed using Sigma Plot 12.0 (Palo Alto, CA, USA) to verify the assumptions of normality and homogeneity of variances. A one-way analysis of variance (ANOVA) was used to assess the effect of the radiometer model on irradiance values, followed by Tukey’s post hoc test for multiple comparisons. The significance level was set at α < 0.05. Results: No statistically significant difference in irradiance was found between D1 (control) and D2. However, significantly lower values were recorded with A2, while D3, D4, and A1 produced significantly higher irradiance values compared to the control (p < 0.05). Conclusion: Irradiance measurements can vary significantly depending on the radiometer model used. Clinicians should be aware of this variability and are encouraged to regularly check the irradiance of the light-curing units used in daily practice, ensure their proper maintenance, and implement periodic monitoring to maintain effective clinical performance. Full article

Three-dimensional printing is rapidly growing in applied dentistry. In order to print faster, increase workflow, and minimize the consumption of resin material, it is important to use the right printer and the correct printing orientation. The objective of the present report is to analyze the flexural strength of specimens realized with two different dental light-curing resins (Keyguide and C&B) obtained from two different Digital Light Processing (DLP) 3D printers. Different printing orientations (0°, 45°, and 90°) were evaluated. 3D Builder, MeshMixer, RayWare, and Chitubox software were used to design the resin specimens. A total of 15 Keyguide and 15 C&B specimens in the shape of a rectangular parallelepiped, with dimensions of 2 mm × 2 mm × 25 mm, were obtained with the Sprintray Moonray S 3D printer, and the 15 Keyguide and 15 C&B specimens presented the same characteristics as those printed using the Moon Night printer. Prior to sample printing, a calibration protocol (tolerance test and dimensional accuracy test) was performed using RayWare software. This procedure allowed compensation for resin shrinkage or expansion, thus ensuring dimensional consistency in all printed samples. Each resin specimen, after printing and post-processing (MoonWash 2 and MoonLight 2), was subjected to a mechanical test with a universal testing machine. After breaking the specimen, the flexural strength values were recorded with computer software (Bluehill, Instron Corporation, Canton, MA, USA). According to the results obtained, the printing orientation of the specimens does not affect the flexural strength of the two materials examined. However, at the maximum load, some differences emerged for both materials printed with the Moon Night printer, depending on their build angle. Both light-cured resins tested had a higher maximum load resistance when printed with the newer Moon Night printer. This result could be due to the Moon Night printer’s better construction characteristics compared to those of the Sprintray or to issues related to the dimensional calibration of the specimens. Full article

(1) Background: The work aims to determine different chemical and mechanical properties with and without BPA dental resin–matrix composites under the same curing and testing conditions. (2) Methods: Disc-shaped specimens were prepared from six resin–matrix composites used in dentistry, three with BPA (BE-Brilliant EverGlow^TM, ED-IPS Empress Direct, FS-Filtek^TM Supreme XTE) and three without (AF-Admira Fusion, BF-Enamel Plus HRi Bio Function Enamel, N/C). Specimens were photoactivated using an LED light-curing unit. The chemical and mechanical properties were analysed. (3) Results: The FS group exhibited the most significant water sorption (31.17 µg/mm³), while the BF showed the lowest (12.23 µg/mm³). Regarding the diffusion coefficient, the result recorded for the group AF is faster-absorbing water, and the group NC is slower. In both test methods (biaxial flexural strength and compressive strength), the resistance to flexural loading of the AF group was significantly lower than all other resin composites evaluated. (4) Conclusions: According to all the parameters studied, we verified that the BF presents the best chemical–mechanical behaviour. Resins free of BPA may not influence chemical–mechanical performance. However, the inorganic matrix has more influence on mechanical properties than the organic matrix. Full article

Dental researchers and manufacturers use the ISO 4049 standard to determine the depth of cure (DoC) of resin-based composites (RBCs). This standard uses a 4 mm diameter stainless-steel mold and subsequently divides the length of the remaining hard RBC by 2. However, the DoC values obtained using this mold have been challenged. Six bulk-fill RBCs (Tetric plus Fill, Tetric plus Flow, Tetric PowerFill, Tetric PowerFlow, Filtek One, and Aura Bulk Fill) were used to investigate the limitations of the 4 mm diameter mold used in the ISO 4049 standard when compared to a 6 mm diameter metal mold that represented the dimensions of a large cavity in a tooth. Two distinct light curing units were used. One light (Elipar S10) emitted a single peak wavelength of light, while the other (Bluephase G4) was a broad-spectrum, multiple-peak curing light. After 10 s of photocuring, the uncured RBC was immediately removed using acetone. The maximum length of the hard RBC remaining was measured and divided by two so that the effect of these two mold diameters on the DoC results could be compared. The DoC of all six RBCs tested was consistently greater in the 6 mm diameter mold (p < 0.0001). Sectioning revealed that the solvent-dissolved specimens had a clear internal boundary between the apparently well-cured RBC and a peripheral, solvent-resistant, “frosty” region. Using a 4 mm diameter stainless-steel mold resulted in a reduced depth of cure values compared to those obtained when the 6 mm diameter mold was used. The use of a broad-spectrum, multiple-peak LED curing light proved unnecessary for photocuring the six RBCs used in this study. Full article

This study aimed to investigate the impact of varying concentrations of graphene oxide (GO) combined with two surface coating agents (SCAs) and two dental adhesives (DAHs) used as SCAs on microhardness. Two SCAs, Resin Glaze (ReG) and Coat-It (CoI) (Shofu Inc., Kyoto, Japan), along with two DAHs, Adper^TM Scotchbond^TM Multi-purpose Adhesive (AdA) (3M ESPE, Seefeld, Germany) and OptiBond^TM FL Adhesive (OpA) (Kuraray Noritake Dental Inc., Okayama, Japan), were tested. The ten concentrations of GO—0 wt % (control), 0.05 wt %, 0.1 wt %, 0.3 wt %, 0.5 wt %, 0.7 wt %, 1 wt %, 2 wt %, 5 wt %, and 10 wt %—were incorporated into the SCAs and DAHs to create the experimental formulations. These mixtures underwent centrifugation for homogenization, followed by sonication for dispersion. The mixture was poured into the 3D-printed resin mold (10 mm in diameter and 1 mm in height) and then cured with a light curing unit for 180 s. The cured specimens were then kept in distilled water at 37 ± 1 °C for 24 h. All specimens were then subjected to evaluation of their microhardness properties using a Knoop hardness testing machine. Data were collected, and the statistical analysis was conducted using Two-way ANOVA followed by Tukey’s post-hoc tests at a 0.05 level of significance. According to the results, surface hardness was significantly increased (p < 0.05) when 0.3–0.7 wt % of GO was added to ReG, CoI, and AdA, compared to the control group. However, surface hardness was significantly increased (p < 0.05) when 0.05–0.3 wt % of GO was added to OpA compared to the control group. In the control groups, the microhardness of OpA was significantly higher than that of the other groups (p < 0.05). In the 0.1 wt % groups, the microhardness of OpA was significantly higher than that of the other groups (p < 0.05). At 0.5 wt %, ReG, CoI, and AdA showed significantly higher microhardness compared to their respective control groups (p < 0.05). In the 1–10 wt % groups, the microhardness of ReG, CoI, and AdA demonstrated a gradual, significant decrease compared to the 0.7 wt % groups. Whereas in the 0.5–10 wt % groups, the microhardness of OpA showed a significant gradual decrease compared to the 0.3 wt % group. In summary, the optimal GO concentration could improve the surface hardness of ReG, CoI, AdA, and OpA. Full article

The aim of this study was to evaluate the effect of different bleaching protocols, including laser-assisted techniques, on the microhardness, surface roughness, and tribological resistance of selected light-cured composites. Three Estelite Universal Flow composites with different flow properties and G-aenial Universal Flo composites were tested. Each group underwent bleaching procedures using Opalescence agents at 10%, 16%, and 40% concentrations, with and without laser activation. Surface microhardness was assessed using the Vickers method, roughness was measured with 3D confocal laser microscopy, and friction coefficients and wear patterns were evaluated using tribological testing. All bleaching protocols resulted in reduced microhardness and increased surface roughness. The most significant changes were observed after treatment with 40% hydrogen peroxide. Laser application, particularly at 16% concentration of carbamide peroxide, helped to partially mitigate these effects in some materials. Bleaching procedures, especially those involving high peroxide concentrations, significantly deteriorated the surface properties of dental composites, which may have clinical implications for the patients. Full article

Objectives: Dental caries remains a prevalent issue in pediatric dentistry, necessitating restorative materials that not only repair decay but also provide protective benefits. Fluoride-releasing restorative materials have a key function in preventing recurrent caries by inhibiting bacterial activity and promoting remineralization. The objective of this study was to examine fluoride release from three pediatric dental restorative materials—Riva Light Cure HV, Fuji IX GP Fast, and the Cention Forte Filling Material—under different pH and temperature conditions. Methods: Specimens (10 mm diameter and 2 mm thickness; n = 3 for each material) were prepared according to the manufacturers’ instructions; immersed in buffer solutions at pH 4.8, 6.8, and 8.8; and stored at 37 °C and 44 °C. Fluoride release was quantified using ion chromatography at three time points (1 day, 7 days, and 28 days). Results: The data revealed that fluoride release was significantly influenced by pH, temperature, and time (p < 0.05). Riva Light Cure HV exhibited the highest release, particularly in acidic conditions (pH 4.8), reaching 40.14 mg/L at 44 °C after 28 days. The Cention Forte Filling Material and Fuji IX GP Fast also showed increased release over time, but with lower cumulative concentrations. Higher temperatures generally enhanced fluoride diffusion across all materials. Conclusions: These findings emphasize the pivotal impact of environmental factors in fluoride release dynamics. Riva Light Cure HV demonstrated superior fluoride release, particularly in acidic environments, suggesting its potential for high-caries-risk pediatric patients. These insights can inform the selection of restorative materials in pediatric dentistry, optimizing caries prevention strategies. Full article

Objective: Selecting suitable materials and luting agents for single crowns is critical yet challenging, as dentists must consider different factors. This study aimed to assess dentists’ preferences for materials and luting agents under different clinical conditions and evaluate the nonclinical factors influencing their preferences. Methods: A paper-based survey supplemented with photographs illustrating anterior and posterior single-crown preparation designs was used, incorporating three clinical scenarios for each as examples. Participants provided demographic data and were asked to select their preferred material and luting agent for each scenario. Comparisons between the crown material/luting agent choices and dentist/practice characteristics were performed. Significant differences were determined using the chi-square test. Results: Overall, 262 (87.3%) dentists participated in this survey. The top-selected material for anterior preparation designs was lithium disilicate; monolithic zirconia was the most selected for posterior preparation designs. Dual-cure resin was the most selected luting agent for all anterior and posterior clinical scenarios, except for posterior subgingival preparation design. There was a significant association between the dentist’s age and the selection of material and luting agent (p < 0.05) in all clinical scenarios, except for the luting agent selection in the posterior subgingival preparation designs (p < 0.05). Other nonclinical factors yielded mixed results; some preparation designs showed significant differences, while others did not, depending on the clinical scenario. Conclusions: Reliance on new materials and luting agents that require minimally invasive treatment with dental ceramics and resin cement is increasing. However, the choice of materials and luting agents is influenced by clinical presentation and nonclinical factors, making it crucial for dentists to be aware of these factors when selecting materials for single-crown restorations. Clinical Implications: An overall trend was observed for the use of strong monolithic ceramics with adhesive resin cements. These findings could assist dentists in reviewing and re-evaluating material choices in their clinical practices, both at a national and regional level. Additionally, the findings could be useful for dental policy makers, wholesale suppliers, and retail distributors in making future decisions. Full article

A novel resin-based bulk-fill restorative material (ST; Stela SDI, Bayswater, Victoria, Australia) has been recently introduced as a self-curing alternative to traditional light-cured composites. Promoted for its unlimited depth of cure, enhanced aesthetics, and unique primer composition, it aims to address challenges associated with amalgam and light-curing composites. Thus, the aim of this in vitro study was to investigate the performance of the new self-curing polymer-based restorative material, ST, compared to two conventional light-cured composites for direct restoration. The study evaluated compressive strength with and without aging, antibacterial activity, mineral deposition in contact with Phosphate-Buffered Saline (PBS) and artificial saliva, porosity, and wettability of ST (Tetric EvoCeram (TE; Ivoclar Vivadent, Schaan, Liechtenstein) and Clearfil Majesty ES-2 (CM; Kuraray Noritake Dental, Tokyo, Japan)). The data was statistically analyzed (α = 0.05) through one-way and two-way analysis of variance (ANOVA). ST demonstrated significantly higher compressive strength than TE and CM at baseline and after aging (p < 0.001), while aging significantly reduced compressive strength across all materials (p < 0.001). Fracture mode analysis revealed brittle fractures for TE and CM, whereas ST fractured in multiple smaller fragments. CM showed the highest void volume and diameter, significantly differing from ST and TE (p < 0.001). Scanning electron microscopy (SEM) analysis revealed cubical-like crystalline formations on ST’s surface after 28 days of immersion in PBS and saliva, indicating some level of bioactivity, whereas no changes were observed for TE and CM. Wettability testing showed ST had the lowest contact angle (12.24° ± 2.1°) compared to TE (62.78° ± 4.68°) and CM (64.64° ± 3.72°) (p < 0.001). Antibacterial activity testing displayed a significant decrease in bacterial growth for CM compared to ST (p = 0.001) and TE (p = 0.002); however, ST and TE showed no significant differences (p = 0.950). To conclude, ST Automix demonstrated promising results across several key parameters, making it a potential candidate for long-lasting restorative applications. Future studies should explore its long-term clinical performance and investigate formulations that enhance its antibacterial properties. Moreover, the bond strength of these materials to dentin and the cytotoxicity should be evaluated. Full article

The first seconds of light curing are crucial for the development of most properties of dental composites, especially for the 3s high-irradiance curing. This study investigated the influence of rapid high-irradiance curing on temporal development of temperature, transmittance and conversion of bulk-fill composites. Four materials were tested: Filtek One (FO), Tetric PowerFill (PFill), Tetric PowerFlow (PFlow) and SDR flow+ (SDR+) and cured with three curing units (LCU): Valo Cordles, Bluephase PowerCure and Translux Wave in 3s (3 W/cm²), 10s (1 W/cm²) and 20s (1 W/cm²) curing protocols. Light transmittance was measured at 2 and 4 mm, while temperature rise and polymerisation kinetics were evaluated at 4 mm depth during 5 min. Both light transmittance and temperature rise were greatest for SDR+ > PFlow > PFill > FO. The 20s curing protocol resulted in the highest degree of conversion (DC) for all materials and LCUs, but also contributed to the greatest temperature rise. Rapid curing with the 3s protocol caused the lowest temperature rise and the shortest time to reach maximum temperature. The polymerisation and temperature kinetics were strongly dependent on the material. The DC of PFill was statistically similar for 3s, 10s or 20s curing with BPC. Rapid curing is only recommended for materials developed for this purpose. Full article

Bioactive restorative materials are crucial for promoting remineralization and protecting dental tissues through ion release. This study examines how pH and temperature influence the short- and long-term ion (F⁻, Ca²⁺, Sr²⁺, OH⁻, Si, and PO₄³⁻) release from seven commercial materials: Cention Forte Filling Material, Cention Primer, Stela Self Cure, Riva Light Cure HV, Riva Self Cure, Equia Forte HT Fil, and Fuji IX GP Fast. Disks were prepared according to the manufacturers’ instructions; immersed in buffer solutions at pH 4.8, 6.8, and 8.8; and stored at 37 °C and 44 °C. Ion release was measured after 1, 7, and 28 days using ion chromatography and mass spectrometry. Results revealed that ion release was significantly affected by pH, temperature, and exposure time. The highest fluoride (40.14 ± 0.32 mg/L) and calcium (74.23 ± 0.37 mg/L) releases were observed in Riva Light Cure at pH 4.8 and 44 °C after 28 days, with the highest strontium release (5.87 ± 0.06 mg/L) occurring under the same conditions. In contrast, silicon release peaked in Cention Forte Filling (31.72 ± 0.68 mg/L) at pH 4.8 and 37 °C. These findings highlight the impact of environmental factors on material performance, assisting clinicians in selecting optimal restorative materials for long-term dental health. Full article