The impact of chemical and hormonal treatments to improve seed germination and seedling growth of Juniperus procera Hochst. ex Endi.

Purpose: Juniper (Juniperus procera) is a common forest tree species in Saudi Arabia. The decline in many populations of J. procera in Saudi Arabia is mainly due to seed dormancy and loss of natural regeneration. This study assessed the effects of chemical and hormonal treatments on seed germination and seedling growth in juniper plants. Methods: The seeds were subjected to either chemical scarification with 90% sulfuric acid and 20% acetic acid for 6 min or hormonal treatment by seed soaking in two concentrations (50 and 100 ppm) of three growth regulators, namely, indole acetic acid (IAA), gibberellins (GA3), and kinetin, for 72 h. A control group without any seed treatment was also prepared. The experiments were performed in an incubator maintained at room temperature and under a light and dark period of 12 h for 6 w. The germinated seeds for each treatment were counted and removed from the dishes. The selected germinated seeds from different treatments were planted in a greenhouse and irrigated with tap water for another 6 weeks. The hormone-treated seedlings were sprayed with their corresponding hormone concentrations 1 w after planting. Results: The highest percentage of seed germination was significantly recorded after seed soaking in 50 ppm GA3, whereas treatment with IAA (100 ppm) resulted in the best seedling growth. Seedlings treated with the three phytohormones showed a significant increase in photosynthetic pigments, total soluble sugars, proteins, percentage of oil, IAA, GA3, and kinetin contents of juniper seedlings compared with the control value, whereas abscisic acid content was decreased compared with chemical treatments. Conclusion: The investigated different treatments had an effective role in breaking seed dormancy and improving seedling growth of J. procera, which is facing a notable decline in its population worldwide. Moreover, such an effect was more pronounced in the three phytohormones that succeeded in breaking dormancy and growth of the Juniperus plant than in the other treatments.

Marginal fit of 3-unit implant-supported fixed partial dentures: Influence of pattern fabrication method and repeated porcelain firings.

BACKGROUND: Marginal fit significantly impacts the long-term success of dental restorations. Different pattern fabrication methods, including hand-waxing, milling, or 3D printing, may affect restorations accuracy. The effect of porcelain firing cycles on the marginal fit of metal-ceramic restorations remains controversial, with conflicting findings across studies. PURPOSE: The aim was to evaluate the potential effects of multiple porcelain firings (3, 5, 7 cycles) as well as pattern fabrication method (conventional hand-waxing, milling, and 3D printing) on the marginal adaptation of 3-unit implant-supported metal-ceramic fixed partial dentures. It was hypothesized that neither the wax pattern fabrication method nor repeated ceramic firings would significantly affect the marginal adaptation of metal-ceramic crowns. METHODS: In this in-vitro study, 30 Cobalt-Chromium alloy frameworks were fabricated based on pattern made through three techniques: conventional hand-waxing, CAD-CAM milling, and CAD-CAM 3D printing (n = 10 per group). Sixteen locations were marked on each abutment to measure the vertical marginal gap at four stages: before porcelain veneering and after 3, 5, and 7 firing cycles. The vertical marginal gap was measured using direct microscopic technique at ×80 magnification. Mean vertical marginal gap values were calculated and two-way ANOVA and Tukey's post hoc tests were used for inter-group comparisons (α = 0.05). RESULTS: The 3D printing group showed significantly lower (P<0.001) mean vertical marginal gaps (60-76 µm) compared to the milling (77-115 µm) and conventional hand-waxing (102-110 µm) groups. The milling group exhibited a significant vertical gap increase after 3 firing cycles (P<0.001); while the conventional (P = 0.429) and 3D printing groups (P = 0.501) showed no significant changes after 7 firing cycles. Notably, the vertical marginal gap in all groups remained below the clinically acceptable threshold of 120 µm. CONCLUSION: CAD-CAM 3D printing provided superior marginal fit compared to CAD-CAM milling and conventional hand-wax pattern fabrication methods. The impact of porcelain firing on the mean marginal gap was significant only in the milling group. All three fabrication techniques yielded clinically acceptable vertical marginal adaptation after repeated firings. Additive manufacturing holds promise to produce precise implant-supported prostheses.

Ethnoveterinary medicinal plants and their utilization by the people of Soro District, Hadiya Zone, southern Ethiopia.

BACKGROUND: Ethnoveterinary studies are important to maintain the sustainability of livestock health and support people's livelihoods through the provision of food, maintaining livestock health, and other biological resources. This study was carried out in Soro District, southern Ethiopia, to identify, document and analyse plant species with ethnoveterinary uses along with the associated indigenous and local knowledge. MATERIALS AND METHODS: Informants were selected using purposive (key informants) and systematic random sampling (general informants) methods. Data on ethnoveterinary plants and their uses were collected through semi-structured interviews, guided field walks, 13 focus group discussions with five to seven members in each and participant observation. Informant consensus factor and fidelity level were computed to identify the most common livestock ailment categories and the best plant species with ethnoveterinary use, respectively. Preference ranking methods were used to identify the potentially effective ethnoveterinary medicinal plants for the most frequently reported livestock ailments. The use diversity of multipurpose plants with ethnoveterinary importance was analysed using the analytical methods of ethnobotany including priority ranking, comparisons and important indices. The T-test statistic was used to compare knowledge differences among different social groups. RESULTS: A total of 132 plant species in 120 genera and 61 families were reported by informants as having ethnoveterinary uses. The plants are said to be used by the local communities in various ways to treat 50 livestock health problems. Higher number of informants (23.77%) cited Momordica foetida for the treatment of 16 livestock ailments. The highest informant consensus value for this species is associated with its use for treating blackleg in cattle; Nicotiana tabacum was cited for the treatment of 15 livestock ailments mainly recommended for the Lumpy Skin Disease/Ailment of bovines; Croton macrostachyus for treatment of 13 livestock ailments including wooden tongue, FMD in bovines; and Gymnanthemum amygdalinum for nine ailments mainly diarrhoea of all livestock types. Achyranthes aspera is claimed to provide the most effective treatment for Aspiration pneumonia (severe coughing in bovines, sheep and goats) alone, while Croton macrostachyus, Ximenia americana, Allium sativum and Juniperus procera were indicated as potential plant species to treat Lumpy Skin Disease in bovines in the order given. The fidelity level analysis showed that Datura stramonium, Dodonaea viscosa subsp. angustifolia and Asparagus africanus were potential medicinal plant species to treat the respective ailments of rabies, Peste des petits ruminants (PPR) and evil eye/spirit. Multipurpose plant species including Prunus africanus, Combretum molle and Afrocarpus falcatus have been highly threatened as indicated by direct matrix ranking mainly due to collection of fuel wood, construction materials and making household utensils, and farm implements rather than for other uses. CONCLUSION: Soro District has rich and diversified livestock herbal medicinal resources, and indigenous knowledge of remedy preparations and applications is transmitted through generation lines. This resource faces anthropogenic threats with deforestation being the leading factor. Consequently, ethnoveterinary medicinal plants continue to decline before adequate and proper scientific documentation and testing are made. There is a dire need for planning and implementation of appropriate in situ and ex situ conservation strategies and to strive towards ensuring the survival and sustainable utilization of such important plant resources of Soro District. This must be supported by further documentation of the associated indigenous knowledge and pharmacological testing of the key promising species including Balanites aegyptiaca (novel species/NS to treat specific ailment), Brugmansia suaveolens (novel species/NS reported first to treat Livestock ailments/LsAs), Euclea divinorum (NS to treat specific ailments), Grevillea robusta (NS), Hagenia abyssinica (NS for the reported specific ailment), Pentanema confertiflorum (NS), Juniperus procera (NS), Maesa lanceolata (NS), Millettia ferruginea (NS for reported specific ailments), Schrebera alata/NS, Securidaca longepedunculata, Spiniluma oxyacantha/NS, Vepris nobilis (novel species reported first to treat LsAs), Zanthoxylum asiaticum /NS and Ximenia americana (NS for specific ailments). This ethnoveterinary study attempted to fill part of the gaps concerning the prevalent livestock health problems and the associated indigenous and local knowledge in the area.

Oviposition Deterrent Activity of Some Wild Plants for Adult Females of Chrysomya albiceps with Medical and Veterinary Importance.

<b>Background and Objective:</b> <i>Chrysomya albiceps</i> is widely spread worldwide, causing myiasis in both humans and animals and playing a mechanical role in the spreading of helminths, viruses and bacteria. Searching for new and safe alternative control methods is very important to eliminate the transmission of pathogens. This study aims to determine the oviposition-deterrent activity of <i>Juniperus procera</i>, <i>Artemisia absinthium</i>, <i>Rosmarinus officinalis</i> and <i>Hypoestes forskaolii</i> wild plants against adult <i>Chrysomya albiceps</i>. <b>Materials and Methods:</b> The effect of plant extracts from <i>Juniperus procera</i>, <i>Artemisia absinthium</i>, <i>Rosmarinus officinalis</i> and <i>Hypoestes forskaolii</i> plants were tested against adult females of <i>Chrysomya albiceps</i> for oviposition deterrent or repellency. These extracts resulted in oviposition deterrent efficacy for adult females of <i>C. albiceps</i> based on the plant type, plant part (leaves or stems), extract type (methanol, acetone and petroleum ether) and tested dose. <b>Results:</b> The highest anti-oviposition activity against <i>C. albiceps</i> females presented from <i>A. absinthium</i> stems acetone extract at a dose of 1 mg cm² by 100 %, while at 0.5 mg cm² recorded remarkable repellency by 86.7% as compared with the control treatment. According to the dose-response relationship, <i>A. absinthium</i> methanol and acetone extracts were ED₅₀ values of 0.85, 0.319 mg cm² (leaves) and 1.88, 0.576 mg cm² (stems), followed by <i>J. procera</i> methanol extract by 0.983 mg cm² (leaves) and 0.98 mg cm² (stems), respectively achieved highest oviposition deterrent efficiency as compared with other extracts. <b>Conclusion:</b> The high repellency activities of these extracts can be utilized to stop <i>C. albiceps</i> flies from laying eggs on wounds and transmitting myiasis diseases to humans and animals and could potentially replace pesticides used in the future control programs of flies.

Ethnobotanical, ecological and health risk assessment of some selected wild medicinal plants collected along mafic and Ultra Mafic rocks of Northwest Pakistan.

The current study investigated wild plant resources and health risk assessment along with northern Pakistan's mafic and ultramafic regions. Ethnobotanical data was collected through field visits and semi-structured questionnaire surveys conducted from local inhabitants and healers. Six potentially toxic elements (PTEs) such as lead (Pb), cadmium (Cd), nickel (Ni), chromium (Cr), manganese (Mn), and zinc (Zn) were extracted with acids and analyzed using atomic absorption spectrophotometer (AAS, Perkin Elmer-7000) in nine selected wild medicinal plants. Contamination factor (CF), pollution load index (PLI), estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) were used to determine the health risk assessment of the studied medicinal plants. The results showed that the selected medicinal plants were used for the treatments of cough, joint swelling, cardiovascular disorders, toothaches, diabetes, and skin pimples by the local inhabitants due to their low-cost and easy accessibility. The concentrations of Pb (3.4-53 mg kg-1), Cd (0.03-0.39 mg kg-1), Ni (17.5-82 mg kg-1), Cr (29-315 mg kg-1), Mn (20-142 mg kg-1), and Zn (7.4-64 mg kg-1) in the studied medicinal plants were found above the safe limits (except Zn) set by WHO/FAO/USEPA (1984/2010). The Pb contamination factor was significantly (p < 0.05) higher in A. modesta (7.84) and D. viscosa (6.81), and Cd contamination factor was significantly higher in C. officinalis (26.67), followed by A. modesta (8.0) mg kg-1. Based on PTE concentrations, the studied plants are considered not suitable for human consumption purposes. Pollution load index values for A. modesta, A. barbadensis, A. caudatus, A. indica, C. procera (2.93), D. viscosa (2.79), and C. officinalis (2.83), R. hastatus (3.12), and Z. armatum were observed as 1.00, 2.80, 2.29, 2.29, 2.93, 2.79, 2.83, 3.12 and 2.19, respectively. Hazard index values were in order of R. hastatus (1.32 × 10-1) ˃ C. procera (1.21 × 10-1) ˃ D. viscosa (1.10 × 10-1) ˃ A. caudatus (9.11 × 10-2) ˃ A. barbadensis (8.66 × 10-2) ˃ Z. armatum (7.99 × 10-2) ˃ A. indica (6.87 × 10-2) ˃ A. modesta (5.6 × 10-2) ˃ C. officinalis (5.42 × 10-2). The health risk index values suggested that consumption of these plants individually or in combination would cause severe health problems in the consumers. Pearson's correlation results showed a significant correlation (p ≤ 0.001) between Zn and Mn in the studied medicinal plants. The current study suggests that wild medicinal plants should be adequately addressed for PTEs and other carcinogenic pollutants before their uses in the study area. Open dumping of mining waste should be banned and eco-friendly technology like organic amendments application should be used to mitigate PTEs in the study area.

Calotropis procera extract inhibits prostate cancer through regulation of autophagy.

Current treatment options available for prostate cancer (PCa) patients have many adverse side effects and hence, new alternative therapies need to be explored. Anticancer potential of various phytochemicals derived from Calotropis procera has been studied in many cancers but no study has investigated the effect of leaf extract of C. procera on PCa cells. Hence, we investigated the effect of C. procera leaf extract (CPE) on cellular properties of androgen-independent PC-3 and androgen-sensitive 22Rv1 cells. A hydroalcoholic extract of C. procera was prepared and MTT assay was performed to study the effect of CPE on viability of PCa cells. The effect of CPE on cell division ability, migration capability and reactive oxygen species (ROS) production was studied using colony formation assay, wound-healing assay and 2',7'-dichlorodihydrofluorescein diacetate assay, respectively. Caspase activity assay and LDH assay were performed to study the involvement of apoptosis and necrosis in CPE-mediated cell death. Protein levels of cell cycle, antioxidant, autophagy and apoptosis markers were measured by western blot. The composition of CPE was identified using untargeted LC-MS analysis. Results showed that CPE decreased the viability of both the PCa cells, PC-3 and 22Rv1, in a dose- and time-dependent manner. Also, CPE significantly inhibited the colony-forming ability, migration and endogenous ROS production in both the cell lines. Furthermore, CPE significantly decreased NF-κB protein levels and increased the protein levels of the cell cycle inhibitor p27. A significant increase in expression of autophagy markers was observed in CPE-treated PC-3 cells while autophagy markers were downregulated in 22Rv1 cells after CPE exposure. Hence, it can be concluded that CPE inhibits PCa cell viability possibly by regulating the autophagy pathway and/or altering the ROS levels. Thus, CPE can be explored as a possible alternative therapeutic agent for PCa.

Fracture Resistance and Failure Mode of Monolithic Zirconia, Veneered Zirconia, and Metal-Ceramic Full-Coverage Restorations: A Comparative In Vitro Study.

PURPOSE: To evaluate and compare the fracture mode and strength of monolithic zirconia to veneered zirconia and metal-ceramic full-coverage restorations following artificial aging and to test the performance of translucent zirconia in terms of load-bearing capacity. MATERIALS AND METHODS: Two mandibular first molars were prepared and scanned for their respective groups of full-coverage restorations. A total of 75 full-coverage restorations were fabricated and divided into five groups: two groups for monolithic zirconia, two groups for veneered zirconia, and one group for metal-ceramic. Then, 75 light-cured hybrid composite resin dies were fabricated to serve as abutments. Before cementation, all full-coverage restorations were subjected to accelerated aging. After cementation, all full-coverage restorations were subjected to compressive loading until fracture in an electromechanical universal testing machine. A two-way nested ANOVA and Tukey test were used to analyze the results with 95% confidence levels. RESULTS: Monolithic zirconia full-coverage restorations showed the highest mean fracture resistance of 4,201.0 N, followed by metalceramic full-coverage restorations of 3,609.3 N, and veneered zirconia full-coverage restorations showed the lowest mean fracture resistance of 2,524.6 N. The main mode of failure was cohesive bulk fracture for the monolithic zirconia group, cohesive/adhesive failure with infrastructure damage for the veneered zirconia group, and cohesive/adhesive failure without infrastructure damage for the metal-ceramic group. CONCLUSIONS: Monolithic zirconia full-coverage restorations showed superior resistance to fracture compared to metal-ceramic full-coverage restorations and are highly reliable in terms of load-bearing capacity within the posterior regions of the mouth.

The effect of repeated porcelain firings on the marginal fit of millable and conventional casting alloys.

The durability of dental restorations is highly determined by an accurate marginal fit, which is in turn affected by the high temperature of porcelain firing. Information is inadequate about the marginal adaptation of metal-ceramic restorations fabricated by soft metal milling technologies after repeated firings. This study aimed to compare the effect of repeated ceramic firings on the marginal fit of copings fabricated from cobalt-chromium through soft metal milling and a conventional nickel-chromium casting alloy. A single standard brass die was designed, machined, and scanned, based on which, 20 frameworks were designed and fabricated through either soft metal milling or conventional casting (n = 10 per group) and porcelain veneered. The vertical marginal fit of the metal copings was measured after 3, 5, and 7 firing cycles by using a digital microscope on 16 points around the finish line of the metal die at ×80 magnification. The data were analyzed through repeated measures ANOVA and independent t-test (α = 0.05). The marginal fit of neither metal group was significantly affected by the number of firing cycles (P = 0.747). However, the marginal discrepancy was statistically lower in the soft metal milling group than that in the casting group (P<0.001). Repeated porcelain firings did not significantly affect the marginal fit of either alloy and remained within the clinically acceptable range after firings. However, the milled alloy had superior marginal fit regardless of the number of firing cycles.

Evaluation of the relationship between metallurgical properties and metal-ceramic bond characteristics of Co-Cr alloys manufactured by different techniques.

STATEMENT OF PROBLEM: Metal-ceramic restorations made from cobalt chromium (Co-Cr) alloy have been increasing, but studies on the effects of different manufacturing techniques on metal-ceramic interface characteristics and metal-ceramic bond strength are sparse. PURPOSE: The purpose of this in vitro study was to examine the metal-ceramic interface and the metal-ceramic bond strength of a Co-Cr alloy produced by casting, milling, and selective laser melting (SLM) with or without thermal cycling. MATERIAL AND METHODS: Co-Cr alloys were prepared by casting, milling, and SLM. Two different SLM devices were used. Ninety-six specimens (25×3×0.5 mm) were manufactured. The structure of the oxidation surface of Co-Cr specimens was examined by scanning electron microscopy (SEM) and by X-ray fluorescence spectroscopy (XRFS). After porcelain application, selected specimens were thermal cycled, and the strength of the metal-ceramic bond was measured by the 3-point bend test. All specimens were analyzed for failure type with a stereomicroscope. The elemental composition and morphology of the metal-ceramic interface were examined by XRFS and SEM with energy-dispersive X-ray (EDX). The results of bond strength were analyzed using a 2-way analysis of variance (ANOVA) for manufacturing methods and testing conditions and the Tukey honest significant difference (HSD) test (α=.05). RESULTS: The main effect of the interactions of the testing condition and manufacturing method variables on the bond strength variable was not statistically significantly different. No significant differences were found among the testing conditions tested (P=.638). Significant differences were found among the manufacturing methods tested statistically (P<.001). Statistically significant differences were found in the CAD-CAM and CONSEPT LASER groups, the CAD-CAM and SLM LASER groups, the CAD-CAM and CAST groups, and the CAST-SLM LASER groups (P<.05). Differences were observed among the interface morphologies of casting, milling, and the two SLM groups. CONCLUSIONS: The bond strength between Co-Cr alloy and ceramic is affected by the manufacturing method. The metal-ceramic bond strength is independent of thermal cycling. The bond strength value in all groups was over 25 MPa, which has been considered clinically acceptable. The interface metallurgical structures of Co-Cr alloys were affected by different manufacturing techniques.

Recycling selective laser melting alloy powder on cobalt chromium-to-ceramic bond strength.

STATEMENT OF PROBLEM: Reusing the powder in selective laser melting machines after multiple cycles is a cost-effective procedure for dental laboratories. However, information on the metal-ceramic bond strength of the framework fabricated by using recycled powder is lacking. PURPOSE: The purpose of this in vitro study was to investigate how the bonding agent and repeated alloy powder reuse affected the metal-ceramic bond strength of cobalt chromium frameworks fabricated by using selective laser melting. MATERIAL AND METHODS: Four square and 40-bar-shaped cobalt chromium frameworks were fabricated by selective laser melting. Half were produced by using virgin alloy powder (Group V; nsquare=2, nbar=20), and half with 30-times reused powder (Group R; nsquare=2, nbar=20). The particle size of each powder was measured by using scanning electron microscopy, and its phase composition was characterized by using radiograph diffraction. Each group was divided into 2 subgroups (Group W [Wash Opaque] and Group N [NP-Bond]) according to the brand of bonding agent used. After ceramic application, the metal-ceramic bond strengths were evaluated by using 3-point bend tests. The bonding agents' chemical composition was analyzed by using radiograph fluorescence. Bond strength data were analyzed by using a 2-way analysis of variance (α=.05). RESULTS: Mean ±standard deviation bond strengths did not differ significantly (P>.05) between Groups V (31.25 ±4.65) and R (30.88 ±4.78). Group W (35.34 ±1.78) had significantly higher bond strength than Group N (26.80 ±1.74; P<.001). Radiograph diffraction analysis found that the phase composition of all powders was similar. The bonding agent in Group W contained cerium, whereas, that in Group N did not. CONCLUSIONS: Metal-ceramic bond strength was unaffected by alloy powder reuse. However, the bonding agent brand may affect the bond strength of cobalt chromium frameworks fabricated by using selective laser melting.

Bond strength of ceramic veneered CAD-milled alloy upon prolonged sintering.

OBJECTIVES: Ceramic-sintering affects bond strength and longevity of metal-ceramic. This study investigated the effect of sintering temperatures and times on metal-ceramic bond strength vis-a-vis interfacial fracture toughness. MATERIALS AND METHODS: One hundred eighty rectangular-shaped (25 × 8 × 1 mm) casting (Auriloy® (CA)) and CAD-milling (Ceramill Sintron® (MA)) alloys were prepared and randomly veneered with ceramic at normal (930 °C; (TN)), increased (940 °C; (TI)), and extremely increased (950 °C; (TE)) sintering temperatures and normal (1 min; (HN)), increased (2 min; (HI)), and extremely increased (3 min; (HE)) sintering time (n = 10/group). Pre-cracked was subjected to four loading-unloading cycles at 0.05 mm/min speed to determine interfacial fracture toughness from strain energy release rate (G). Microstructures were examined with a scanning electron microscope (SEM), energy-dispersive X-ray (EDX), and atomic force microscopy (AFM). ANOVA and Tukey comparisons were determined for significant differences (α = 0.05). RESULTS: Significant differences in G due to the effect of alloy, sintering temperature, and time (p < 0.05) were indicated. MA revealed higher G than CA. Raising temperatures enabled increasing G for CA, not for MA. Extended sintering permitted increasing G for both alloys. Rougher surface of MA than CA was observed. Interfacial ion exchange was differently indicated between CA and MA. CONCLUSIONS: Bond strength was influenced by alloy, sintering temperature, and time. Ceramic has better adhesion to MA than CA. Enhancing bond for CA was succeeded through increasing sintering temperature and time, whereas through extended sintering for MA. CLINICAL RELEVANCE: MA offers stronger bond than CA. Enhancing bond is suggested by extended sintering. Raising temperature can enhance bond for CA, not for MA.

Research on the Role of Surface Treatment of the Metal Surface on the Strength of the Metal-Ceramic Bond.

AIM: The aim of the present study is to investigate the metal-ceramic bond strength as a result of three different surface treatment methods: (1) oxidation, (2) oxidation and sandblasting, and (3) double oxidation on the metal substrate. MATERIALS AND METHODS: A total of 72 metal substrates were made from two different types of metal-ceramic alloys (n = 36): group I, Ni-Cr and group II, Co-Cr alloys. Each group was further divided and subjected to three different surface treatments (n = 12): (1) oxidation in accordance with the manufacturer's instructions; (2) oxidation according to the manufacturer's instructions and then sandblasting with Al2O3, with a grain size of 110 µm, a pressure of 75 psi for 10 sec with a distance of 5 cm and steam cleaning; and (3) double oxidation. The bond strength of the specimens was evaluated with the three-point bending process. The data were recorded, tabulated, and statistically analyzed. RESULTS: For group I, the materials with oxidation based on the specifications, show mean value of 64.02 Nt. The oxidation and sandblasting materials have mean 55.92 Nt. The double oxidation materials have mean 55.47. For group II, the materials with oxidation based on the specifications, show mean value of 58.46 Nt. The oxidation and sandblasting materials have a mean value of 42.56 Nt. The double oxidation materials have mean 42.96 Nt. CONCLUSION: The best method of treatment of the metal substrate is specification oxidation, in terms of the strength of the metal-ceramic bond. Further treatment of the metal substrate reduces the strength of the metal-ceramic bond. CLINICAL SIGNIFICANCE: A prerequisite for clinical success of metal-ceramic prosthetic restorations is the increased strength of the bond between ceramic material and metal substrate. With that in mind, the present research gives important insight into best practices for prosthetic restorations.

Cobalt chromium alloys in fixed prosthodontics: Investigations of mechanical properties and microstructure.

STATEMENT OF PROBLEM: Cobalt chromium (Co-Cr) alloys possess beneficial mechanical properties because alloys, even in thin sections, can resist high mastication forces and exhibit an acceptable bond to the surface porcelain layer. Traditional manufacturing techniques of Co-Cr alloys such as casting have been replaced with newer fabrication techniques, such as milling, laser melting, and presintered milling. Despite scarce documentation, these new manufacturing techniques are being used to fabricate dental and implant constructions. PURPOSE: This in vitro study investigates the hardness, yield strength, elastic modulus, and microstructure of the most commonly used Co-Cr alloys for fixed prosthodontics based on manufacturing technique. In addition, this study investigates the effect of heat treatment on the mechanical properties and microstructure of these materials. MATERIAL AND METHODS: Five Co-Cr alloys were included (dumbbell and rectangular shaped) based on four manufacturing techniques: cast, milled, laser melted, and presintered milled. Commercially pure titanium grade 4 and titanium-6 aluminum-4 vanadium ELI (extra low interstitial) were included for comparison, and yield strength and elongation after fracture were evaluated. The specimens were tested for hardness using the Vickers test and for elastic modulus using a nondestructive impulse excitation technique. The microstructure of selected specimens was analyzed using focused ion beam-scanning electron microscopy (FIB-SEM) and energy dispersive X-ray spectroscopy (EDS). RESULTS: The mechanical properties depend on the manufacturing technique used; the laser-melted and presintered Co-Cr specimens demonstrated the highest mechanical properties, followed by the milled and cast groups. Both the laser-melted and the presintered milled Co-Cr specimens showed smaller grain size compared with the cast and milled Co-Cr specimens. The titanium-6 aluminum-4 vanadium ELI demonstrated higher hardness and yield strength compared to commercially pure titanium grade 4. No major differences were observed for the selected materials regarding the mechanical properties and microstructural appearance after heat treatment. CONCLUSIONS: The laser melting and presintered milling techniques produced higher mechanical properties compared with the cast and milled Co-Cr. These findings were confirmed through microstructural analysis with respect to the grain size, precipitation, and number of pores.

Effect of the CAD-CAM and lost-wax framework fabrication techniques on the fracture strength of porcelain in metal-ceramic restorations.

BACKGROUND: Ceramic fracture is a common problem in metal-ceramic restorations (MCRs). The advent of computer-aided design and computer-aided manufacturing (CAD-CAM) technology eliminated the lost-wax technique, which was responsible for many of the problems associated with framework fabrication. However, the role of the CAD-CAM technology in decreasing porcelain fracture is not yet known. OBJECTIVES: The aim of the present in vitro study was to compare the fracture strength of porcelain in MCRs with metal frameworks fabricated with the use of the lost-wax and CAD-CAM techniques. MATERIAL AND METHODS: Twenty metal dies were prepared with a deep chamfer finish line, with a depth of 1.2 mm and the occlusal taper of the walls of 8°, a 2-millimeter occlusal reduction of the functional cusp, a 1.5-millimeter occlusal reduction of the nonfunctional cusp, and the functional cusp bevel. Ten frameworks were fabricated using the CAD-CAM system and 10 with the lost-wax technique. After porcelain veneering, the specimens underwent thermocycling and cyclic loading to simulate the aging process. The load test was then performed. The fracture strength of porcelain was compared between the 2 groups, and the mode of failure was also determined using a stereomicroscope. RESULTS: Two specimens were excluded from the CAD-CAM group. Thus, 18 specimens were statistically analyzed. The results revealed no significant difference in fracture strength between the 2 groups (p > 0.05). The mode of failure was mixed in all specimens from both groups. CONCLUSIONS: Our results indicated that the fracture strength of porcelain and the mode of failure did not depend on the metal framework fabrication technique (lost-wax or CAD-CAM).

Fundamental Properties and Clinical Application of 3D-Printed Bioglass Porcelain Fused to Metal Dental Restoration.

The purpose of this study is to evaluate the mechanical properties and clinical fitness of 3D-printed bioglass porcelain fused to metal (PFM) dental crowns. To evaluate the mechanical properties, tensile strength, Vickers microhardness, shear bond strength, and surface roughness tests of the SLM printed Co-Cr alloy was conducted. A right mandibular 1st molar tooth was prepared for a single dental crown (n = 10). For a three-unit metal crown and bridge, the right mandibular first premolar and first molar were prepared. Bioglass porcelain was fired to fabricate PFM dental restorations. A clinical gap was observed and measured during each of the four times porcelain was fired. A statistical analysis was conducted. The SLM technique showed the largest statistically significant tensile strength and a 0.2% yield strength value. The milling technique had the lowest statistically significant compressive strength value. The shear bond strength and surface roughness showed no statistically significant difference between the fabricated method. There was a statistically significant change in marginal discrepancy according to the porcelain firing step. The casting technique showed the greatest statistically significant margin discrepancy value. The SLM method showed better fitness than the traditional casting method and showed better mechanical properties as a dental material.

Effects of post-treatment on metal-ceramic bond properties of selective laser melted Co-Cr dental alloy. Part 1: Annealing temperature.

STATEMENT OF PROBLEM: Dental cobalt-chromium (Co-Cr) alloy manufactured by selective laser melting (SLM) is not recommended for clinical applications before annealing because of excessive residual stress. However, limited information is available regarding the relationship between annealing temperature and the metal-ceramic bond properties of SLM Co-Cr alloys. PURPOSE: The purpose of this in vitro study was to investigate the effects of annealing temperature on the metal-ceramic bond properties of SLM Co-Cr alloys. MATERIAL AND METHODS: Four groups with different annealing temperatures (850 °C; 950 °C; 1050 °C; 1150 °C) were prepared by using SLM techniques. Bond strengths were measured by using a 3-point bend test; subsequently, debonded surface morphologies and elements were assessed by using a scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The area fraction of adherence porcelain (AFAP) value was introduced to analyze fracture characteristics. Microstructural and interfacial characteristics were characterized by SEM/EDS and X-ray diffraction analysis. The coefficient of thermal expansion (CTE) test was used to analyze thermal matching. A 1-way ANOVA and the Tukey honestly significant difference tests were used to analyze bond strengths and AFAP values statistically (α=.05). RESULTS: The mean ±standard deviation values of the metal-ceramic bond strengths were 40.68 ±4.34 MPa for the 850 °C group, 37.54 ±5.34 MPa for the 950 °C group, 45.97 ±2.18 MPa for the 1050 °C group, and 50.79 ±1.79 MPa for the 1150 °C group. Significant differences (P<.05) were observed among all groups. Debonded surfaces and AFAP analysis displayed a mixed fracture mode of adhesive and cohesive fracture, and 1150 °C-annealing specimens exhibited better fracture characteristics close to cohesive fractures. As the temperature increased, native oxide film thicknesses remained unchanged; the 850 °C group had the thinnest diffusion layer, while the other 3 groups had similar thicknesses. Although the 1050 °C and 1150 °C groups displayed higher CTE values, their microstructures were more conducive to atomic diffusion and improved chemical bonding. Microstructure analysis found that ε phase and second-phase precipitates jointly affected metal-ceramic bond strength. CONCLUSIONS: Annealing temperatures affected the metal-ceramic bond strengths of SLM Co-Cr porcelain specimens. 1150 °C annealing SLM Co-Cr specimens displayed higher bond strengths and improved fracture and interface characteristics among the 4 groups.

Effects of hollow structures added by selective laser sintering on the mechanical properties of Co-Cr alloy.

PURPOSE: This study investigates the effects of hollow structures, added by selective laser sintering (SLS), on the mechanical properties of a Co-Cr alloy for providing an optimal structural property to the framework components of removable partial dentures (RPDs). METHODS: The specimens produced using the 3D data of the dumbbell-shaped cylinders were divided into four groups based on the manufacturing method: Cast, Mill, SLS-solid, and SLS-hollow. Tensile tests were performed to measure the mechanical properties of the specimens. The mechanical property values among the four groups were statistically compared using the Kruskal-Wallis test followed by the Steel-Dwass test (α = 0.05). RESULTS: The median elastic modulus was the largest in the Cast, followed by SLS-solid, Mill, and SLS-hollow, with no significant differences observed between all conditions. The median ultimate tensile strength was the largest in the order of SLS-solid, Mill, SLS-hollow, and Cast. The median 0.2% proof stress was the largest in SLS-solid, followed by SLS-hollow, Cast, and Mill. The median elongation was the highest in the order of Mill, SLS-solid, SLS-hollow, and Cast. CONCLUSIONS: With the addition of hollow structures, the elastic modulus decreased while the mechanical strength and proof stress remained high in SLS specimens. In addition, the ISO 22674 standard for dental metals was met, suggesting that SLS may be a possible method to design RPD frameworks with high strength and optimal structural properties.

Polyphenols-Rich Extract of Calotropis procera Alone and in Combination with Trichoderma Culture Filtrate for Biocontrol of Cantaloupe Wilt and Root Rot Fungi.

Fungal diseases have always been a major problem for cantaloupe crops; however, synthetic fungicides are hazardous to humans and the environment. Consequently, a feasible alternative to fungicides without side effects could be by using bio agents and naturally occurring plants with antibacterial potential. This study has achieved a novel procedure for managing wilt and root rot diseases by potentially using Trichoderma sp. culture filtrates in consortium with plant extract of Calotropis procera, Rhizoctonia solani, Fusarium oxysporum, and Pythium ultimum, which were isolated from infected cantaloupe roots with identified root rot symptoms. The antagonistic activity of four Trichoderma isolates and analysis of antibiotics and filtrate enzymes of the most active Trichoderma isolate were determined as well as phytochemical analysis of C. procera plant extract using HPLC-UV. The obtained results showed that all Trichoderma isolates considerably lowered the radial growth of P. ultimum, R. solani, and F. oxysporum in varying degrees. The scanning electron micrographs illustrate the mycoparasitic nature of Trichoderma sp. on F. oxysporum. The phytochemical analysis of C. procera indicated that phenolic contents were the major compounds found in extracts, such as vanillin (46.79%), chlorogenic acid (30.24%), gallic acid (8.06%), and daidzein (3.45%) but including only a low amount of the flavonoid compounds rutin, naringenin, and hesperetin. The Pot experiment's findings showed that cantaloupe was best protected against wilting and root rot diseases when it was treated with both Trichoderma sp. culture filtrates (10%) and C. procera extract of (15 mg/mL), both alone and in combination. This study demonstrates that the application of bio agent Trichoderma spp. filtrate with C. procera phenol extract appears useful for controlling wilting and root rot disease in cantaloupe. This innovative approach could be used as an alternative to chemical fungicide for the control of wilting and rot root diseases.

Evaluation of ceramic adherence to cobalt-chromium alloys fabricated by different manufacturing techniques.

STATEMENT OF PROBLEM: Selective laser melting has been increasingly used in the fabrication of metal-ceramic prostheses. The longevity of the prostheses depends on the strength of the metal-ceramic bond, which may differ with the framework manufacturing technique. PURPOSE: The purpose of this in vitro study was to compare the bond strength of ceramic to cobalt-chromium (Co-Cr) alloys fabricated by different manufacturing methods. MATERIAL AND METHODS: Sixty Ø15×2-mm disk-shaped specimens were prepared and assigned to 3 groups (n=20) with different manufacturing methods: milled Co-Cr (M), selective laser melted Co-Cr (SLM), and cast Co-Cr (C). The disks were ceramic layered with a 2-mm thickness. Half of the specimens from each group were thermocycled. The shear bond strength (SBS) test was applied to all specimens. The microstructure changes after ceramic layering were evaluated by X-ray diffraction (XRD). The specimens' surface morphology was analyzed by using scanning electron microscopy (SEM). RESULTS: Thermocycling had a significant effect on SBS values in the SLM group (P=.017). Considering the registered Fmax (force inducing bonding failure), a significant difference was found between SLM and both M and C groups (P<.001). No significant difference was found between milled and cast Co-Cr (P=.885). The failure types were mostly mixed failures. Ceramic layering induced a crystallization increase in groups C and SLM. CONCLUSIONS: The adhesion strength of ceramic to Co-Cr differed with alloy composition and manufacturing technique. The aging process influenced the results in the SLM group.

Ovicidal and miracicidal activities of Calotropis procera and its green-synthesized nanotized derivative: A quest for new antifasciola agents.

Fascioliasis is an important zoonotic disease but treatment with the mainstay drugs poses challenge of parasite resistance. The aim of the study was to determine the anthelmintic efficacy of ethanolic leaf extract of Calotropis procera (CP) and its synthesized silver nanoparticles (AgNPs) against the eggs and miracidia of Fasciola species. The ethanolic extract of C. procera was used to synthesise its corresponding green-synthesis derivative using silver nitrate (CP-AgNPs). The synthesized silver nanoparticles were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD) and Scanning Electron Microscopy/Energy Dispersive X-ray (SEM/EDX). The ova and miracidia of Fasciola spp. were exposed to 1, 2, and 4 mg/ml CP ethanolic extracts and its corresponding AgNPs. FTIR showed that the formulation was capped with compounds present in the extract. The XRD showed the crystalline property of CP-AgNPs. The SEM image showed clusters of irregularly shape nanoparticles. The ovicidal activities were concentration dependent and showed highest activities 81.02±4.03% and 92.91±1.25% in 4 mg/ml CP and CP-AgNPs respectively (p < 0.05). The LC50 of CP (1.49 mg/ml) was more than 3 folds higher than that of CP-AgNPs (0.47 mg/ml). While CP did not cause miracidia death after 60 min exposure, however, 100% miracidia death were observed within 30 min exposure in all the tested concentration with CP-AgNPs. The positive control (ABZ) only showed 100% mortality after 60 min of exposure of miracidia. The study showed that green-synthesised C. procera nanoparticles showed superior ovicidal and miracicidal activities over C. procera leaf extracts and could be a source of potential antifasciola agent.