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Background: The advancement of digital dentistry enhanced the fabrication of indirect provisional restorations utilizing durable materials, yet the performance of provisional crowns fabricated with various techniques, and different thickness remains unknown. Thus, this in-vitro study aimed to evaluate the influence of restoration thickness and aging on the fracture behavior of provisional crowns fabricated using different techniques. Methods: A dentiform maxillary first molar was prepared using a highly filled epoxy resin material to construct identical die replicas. Four groups of provisional crowns were fabricated: Group 1 was milled at 1.5 mm occlusal thickness; Group 2 was milled at 0.9 mm thickness; Group 3 was 3D-printed at 1.5 mm occlusal thickness; and Group 4 was 3D-printed at 0.9 mm occlusal thickness. Eight crowns from each group were subjected to a thermocycling process for 5000 cycles between baths held at 5 °C and 55 °C with a dwell time of 30 s and transfer time of 5 s. All crowns (aged and non-aged (control)) were loaded for fracturing using a universal testing machine at a 0.5 mm/min crosshead speed. Data were analyzed using a two-way analysis of variance and multiple comparisons at (α = 0.05). Results: The maximum mean force load was found in the non-aged milled group (M1.5) at 1706.36 ± 124.07 N; the minimum mean force load was recorded for the aged 3D-printed group (3D0.9) at 552.49 ± 173.46 N. A significant difference was observed before and after thermocycling (p

In this work, cadmium doped cobalt nickel ferrites were fabricated via co-precipitation method by using high purity chlorides as precursors and ammonia as precipitate. XRD measurements of synthesized Co0.6Ni0.4-xCdxFe2O4 ferrite samples revealed that the formation of mono phase cubic spinel structure ferrite nanoparticles. The volume of unit cell, crystallite size, lattice constant, bond length, hopping length, ionic radii and microstrain were directly affected by the inclusion of Cd2+ content in Co-Ni ferrite. The crystallite size (Dxrd) of prepared ferrite samples was obtained in between 14.52 and 16.92 nm. FTIR spectra showed two main absorption bands in the frequency range of 400–600 cm−1 arising due to stretching vibrations of tetrahedral (A) and octahedral (B) sites respectively. SEM analysis showed agglomerated morphology of ferrite nanoparticles with grain size decreased from 0.85 to 0.21 μm. Raman spectroscopy confirmed that, on addition of Cd2+content, Raman band was shifted towards higher wave number side. The crystallite development in Cd doped Co-Ni ferrites was explored by X-ray peak broadening methods such as Scherer’s formula, Size-Strain plot and Williamson hall methods. XRD analysis confirmed, the crystallite size and microstrain of Co0.6Ni0.4-xCdxFe2O4 ferrites were obtained from various methods, are highly inter correlated. Saturation magnetization (Ms) was decreased from 29.92 to 23.40 emu/gm with increase of Cd doping. The coercivity was reduced from 1113 to 708 Oe with Cd concentration. This is due to the magnetic anisotropy constant of Ni2+ ion is higher than that of the Cd2+ ion.

Titanium-based dental prostheses are essential for prosthodontics and can now be 3D printed using powder bed fusion (PBF) technology with different densities by controlling the process parameters. This study aimed to assess the surface topography and bonding strength of dental resins made of 3D-printed titanium alloys with varying densities and growth directions. Three groups of titanium alloy (Ti6Al4V) specimens differentiated by density (low, medium, and high) were produced using laser-melting 3D printing technology (N = 8). Each group included specimen surfaces with vertical and horizontal growths. Vickers microhardness, surface profilometry, wettability, and shear bond strength (SBS) of the titanium samples were measured for all groups. Scanning electron microscopy (SEM) was performed. Statistical analyses were conducted using a two-way ANOVA and Fisher’s multiple test. Higher-density specimens exhibited greater microhardness (p < 0.05), and those with horizontal growth directions were harder (p < 0.05) than their vertical counterparts within the same density category. Additionally, low-density specimens in both growth directions had the highest surface roughness values (p < 0.05) compared to the other groups. The wettability values were similar (p > 0.05) among the groups in the vertical direction, but not in the horizontal direction (p < 0.05). However, the density type did not significantly (p > 0.05) influence the bonding strength of 3D-printed titanium. This study revealed significant variations in surface roughness, contact angle, and microhardness based on density and growth direction.

This in vitro study evaluated the influence of restoration design (bi-layered vs. monolithic) and manufacturing technique on the marginal discrepancy and internal fit of 3-unit zirconia fixed dental prostheses (FDPs). Mandibular second premolars and second molars were prepared as abutments in a 3-unit zirconia bridge to develop four groups (n = 10 FDPs): MZ: Monolithic zirconia FDPs, ZL: zirconia framework veneered by the hand-layering technique, ZP: zirconia framework veneered by the heat-pressed technique, and CAD-on: zirconia framework veneered by CAD/CAM lithium-disilicate glass–ceramic. All the zirconia FDPs were cemented to their corresponding die replicas using dual-cure resin cement and were subjected to compressive cyclic loading at a load range for half a million cycles using a universal testing machine. FDPs were sectioned mesiodistally to measure the marginal gap and internal fit using scanning electron microscopy. The measurements were taken at pre-assigned points of each abutment. Data were statistically analyzed via a Kruskal–Wallis test (α = 0.05). No significant differences were found between the monolithic and bi-layered zirconia groups in terms of the marginal discrepancy. However, there was a significant difference in the marginal gap between the zirconia groups. The marginal gap between monolithic and bi-layered zirconia FDPs was within the clinically acceptable range (

This laboratory study aimed to evaluate the effect of different surface patterns using femtosecond laser treatment on the enclosed mold shear bond strength (EM-SBS) of resin composite to zirconia (ZrO2) surfaces and to contrast it with the widely used tribochemical silica coating (TBC) surface conditioning method. A set of fifteen rectangular ZrO2 blocks were randomly divided into five groups according to surface pretreatment: Control G0—no treatment; G1—TBC with silane application; G2—femtosecond laser irradiation with horizontal lines 30 µm apart; G3—femtosecond laser irradiation with horizontal lines 15 µm apart; and G4—femtosecond laser irradiation with cross lines 30 µm apart. The pretreated surfaces were characterized by a surface profilometer, tensiometer and scanning electron microscope. The EM-SBS of resin composite stubs to ZrO2 was measured followed by fractographic analysis. The surface roughness and water contact angle were observed to be statistically higher among the femtosecond laser groups compared to the TBC and control groups. The G4 group exhibited the highest EM-SBS among all the groups, irrespective of the ageing conditions used. At the end of 5000 thermocycles, G4 exhibited EM-SBS of 14.05 ± 4.21 MPa compared to 13.80 ± 3.01 MPa in G1 and 5.47 ± 0.97 MPa in G0. The two-way ANOVA revealed a significant effect of both study groups and ageing conditions on the EM-SBS (p < 0.001). Utilization of femtosecond laser technology holds promise as a potential and alternative mechanical retention approach for enhancing the bonding strength of the resin composite to ZrO2.

BackgroundChildren's quality of life, academic performance, and future achievement can all be negatively affected by poor dental health. The present study aimed to assess the need for dental health services and the factors influencing their utilization using the Andersen health care utilization model among school children.MethodsThe current cross-sectional study was conducted among schoolchildren aged 13 to 15 in Bangalore, India (n = 1100). A questionnaire was developed using the concepts of the Andersen healthcare usage model. The parents of the children filled out the questionnaire. The factors were investigated using bivariate analysis and multivariate logistic regression analysis.ResultsAbout 78.1% of the children did not utilize dental health services. Regarding the reasons for not visiting a dentist, 65.8% said they did not have a dental problem, and 22.2% said they could not afford it. Bivariate analysis showed that age, gender, education level, occupation of the family's head of household, monthly family income, socioeconomic status, perceived oral health problems, accessibility of dental health facilities, and parental attitudes toward their children's oral health were significantly associated with using dental health services (pConclusionDental health service utilization was low in the past year. The age, number of family members, parent's education level, travel time to the dental facility, the child's oral health behaviors, and positive parental attitude all play a role in a children's utilization of dental health service.

This study aimed to assess dental technologists/technicians knowledge, attitudes, and practice during the COVID-19 pandemic in Saudi Arabia. This cross-sectional study was conducted among workers in dental laboratories in Saudi Arabia. A validated questionnaire was developed based on previous literature and distributed online. The questionnaire assessed the study population's knowledge, attitude, and practice regarding infection control protocol for COVID-19. Descriptive statistics of categorical variables were conducted. The response rate was 58.3%, where most respondents are male at a rate of 97%. Most of the participants (82%) were aware of the various infection control measures for COVID-19 in a dental laboratory. Forty-eight participants showed a level of knowledge range between 80 and 100%, while 27 and 30 participants reported moderate and low level of knowledge, respectively. Only 67% of the participants strongly agree that dental cast and fabricated/repaired restorations should be transferred in a very close and protective package to control infection. About 70% of participants indicated they always wear protective gear/goggles and should be warned while working in the dental laboratory. As the pumice slurry was utilized frequently to clean and polish the prostheses, 66% of participants agreed that pumice slurry should be always changed regularly. Regarding COVID-19 infection control procedures, dental technologists/technicians showed good knowledge, attitude, and practice; however, considering how infectious the virus is, more measures should be taken into consideration. Effective communication and collaboration between the laboratory and the dental clinic are essential for infection control., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Pharmacy and Bioallied Sciences.)

Various 3D printing systems for interim fixed dental restorations are commercially available. This study aimed to evaluate the physical and mechanical properties of 3D printed resins used for interim restorations fabricated using various 3D printing systems and printing angulations after accelerated aging. Three different interim restorative materials were provided and printed using their specific 3D printing systems (A: NextDent; B: Asiga; C: Nova3D), and the testing specimens from each system were printed at two building angles: (1) 0° and (2) 90°. The six groups were A1, A2, B1, B2, C1, and C2, with sixteen specimens per group. Half of the specimens in each group (N = 8) were subjected to accelerated aging, including simulated brushing and thermocycling. Three-point bending, surface roughness, and Vickers microhardness tests were performed. Two-way ANOVA and Fisher's multiple tests were used for statistical analyses. The most accurate systems were found in groups C1 and C2 for length, A1 and B1 for width, and A1 and C1 for height. The specimen trueness only changed after aging for groups B1, B2, and C1. The flexural strength of the A2 group (151 ± 7 MPa) before aging was higher than that of the other groups, and the strength decreased after aging only for groups A1 and A2. The flexural strength, microhardness, and surface roughness of the 3D printed interim resins after aging varied depending on the material, system used, and printing angle.

Purpose: This study assessed the physical and mechanical properties of interim crown materials fabricated using various digital techniques after accelerated aging., Materials and Methods: Three groups of interim dental restorative materials (N = 20) were tested. The first group (CO) was fabricated using a conventional manual method. The second group (ML) was prepared from prefabricated resin blocks for the milling method and cut into specimen sizes using a cutting disc. The third group (3D) was additively manufactured using a digital light-processing (DLP) 3D printer. Aging acceleration treatments using toothbrushing and thermocycling simulators were applied to half of the specimens corresponding to three years of usage in the oral environment (N = 10). Surface roughness (Ra), Vickers microhardness, 3-point bending, sorption, and solubility tests were performed. A 2-way analysis of variance (ANOVA) and Fisher's multiple comparison test were used to compare the results among the groups., Results: The mean surface roughness (Ra) of the resin after accelerated aging was significantly higher in the CO and ML groups than that before aging, but not in the 3D group. All groups showed reduced hardness after accelerated aging. The flexural strength values were highest in the 3D group, followed by the ML and CO groups after accelerated aging. Accelerated aging significantly reduced water sorption in the ML group., Conclusion: According to the tested material and 3D printer type, both 3D-printed and milled interim restoration resins showed higher flexural strength and modulus, and lower surface roughness than those prepared by the conventional method after accelerated aging., (© 2022 The Korean Academy of Prosthodontics.)

Background: All-ceramic restorations have become popular and the trend is ongoing. However, the incidence of chipping within the veneering layer has been a commonly reported failure in clinical practice., Objectives: The aim of this in vitro study was to evaluate the effect of ceramic crown design (monolithic vs bi-layered) and material on the chipping resistance of molar crowns submitted to compressive cyclic loading., Material and Methods: Fifty identical epoxy resin replicas of a mandibular first molar with crown preparation were divided into 5 groups (n = 10) as follows: the MLD group - monolithic CAD/CAM lithium-disilicate glass-ceramic (LDGC) crowns; 30 zirconia cores were veneered with either feldspathic porcelain by hand-layering technique (ZHL) or by heat-pressing technique (ZVP), or with milled LDGC veneers and subsequently fused to the cores (ZLD); 10 porcelain-fused-to-metal (PFM) crowns acted as a control group. All crowns were cemented using Panavia® F2.0 resin cement (Kuraray Dental, Tokyo, Japan). After storage in water at 37°C for 1 week, the specimens were subjected to compressive cyclic loading at the mesiobuccal cusp which was tilted at 30°. A load cycle of 50-450 N was used and specimens were maintained in an aqueous environment throughout 500,000 cycles in a universal testing machine (Instron, Norwood, USA). The data was statistically analyzed at 5% significant level with Fisher's exact test and Kaplan-Meier survival analysis., Results: Significant differences in survival rates of the specimens used in the groups (p < 0.001) were found. Specimens of the PFM, ZHL and ZVP groups underwent failures at different stages of the 500,000 fatigue cycles, while specimens of the MLD and ZLD groups survived the entire fatigue test. ZHL and ZVP crowns had the worst chipping-resistance, while PFM crowns performed slightly better. The Kaplan-Meier test revealed significantly higher survival rates for the MLD and ZLD specimens compared to the other 3 groups., Conclusions: The use of LDGC as a monolithic molar crown and as a veneer over a zirconia core resulted in superior resistance to cuspal chipping.