Wax Pattern Research Articles

Experimental investigation of CF8 stainless steel impeller quality using PLA-based fused deposition modeling-assisted investment casting

Abstract The conventional Investment Casting (IC) process is extensively used for manufacturing parts with intricate shapes and complex geometries. However, its drawbacks include long cycle times and costly tooling, making it ideal for mass production but inefficient for frequent design changes, small batch production, or customized products. To address these challenges, a novel hybrid method known as Fused Deposition Modeling Assisted Investment Casting (FDMAIC) has been developed. In FDMAIC, the wax pattern is replaced by an FDM-printed pattern, while all other steps follow the conventional IC process. In this study, a semi-open impeller for a centrifugal pump was produced using FDMAIC, with Polylactic Acid (PLA) as the pattern material and CF8 for casting. Dimensional accuracy and surface roughness, key indicators of quality, were evaluated at both the printing and casting stages. Critical dimensions such as outer and inner diameters, shroud and blade thicknesses, and total height were measured, along with surface roughness at the shroud and blade surfaces. In the final cast, maximum dimensional deviation was observed in Outer diameter(−2.408 mm), and minimum dimensional deviation was observed in total height(−0.169 mm). The surface roughness values obtained at the shroud and blade surface of the final cast were 4.64 μm 6.67 μm, respectively. Microstructure and hardness testing were also performed on the FDMAIC impeller to validate the process. The results provide detailed insights into the feasibility of FDMAIC and suggest areas for further improvement.

Evaluation of the Effect of Different Construction Techniques on Removable Partial Denture Frameworks: Conventional Wax Pattern,3D Printing Resin, and Metal 3D Printing ( Comparative Vitro Study )

Evaluation of the Effect of Different Construction Techniques on Removable Partial Denture Frameworks: Conventional Wax Pattern,3D Printing Resin, and Metal 3D Printing ( Comparative Vitro Study )

A Comparative Analysis of the Accuracy of Crown Fabricated from Conventional Wax Patterns and CAD/CAM Technology – Milling and 3D Printing

ABSTRACT Background: Digital manufacturing techniques such as milling (subtractive) and 3D printing (additive) are increasingly used in dental restorations. These technologies promise enhanced precision and efficiency compared to traditional methods. However, the accuracy of marginal and internal fits of crowns produced by these techniques remains under-explored. Objective: To evaluate and compare the marginal and internal fit of dental crowns fabricated using two digital manufacturing techniques: Milling (subtractive) and 3D printing (additive). Materials and Methods: A maxillary first molar was replicated to create seven representative dies for each technique. Crowns were fabricated using both milling and 3D printing methods. The fit of the crowns was assessed using the silicone replica technique, measuring occlusal, axial, marginal gaps, and internal fit. Results: 3D printing demonstrated the most precise fit across all measurement points, with significantly smaller discrepancies compared to milling. The two-way ANOVA analysis confirmed a significant effect of the fabrication method on marginal and internal gaps, highlighting the superior performance of 3D printing. However, the silicone replica technique revealed fewer significant differences between the two methods. Conclusion: 3D printing offers enhanced precision and consistency in crown fabrication compared to milling. Despite promising results, further research is necessary to confirm the long-term efficacy and cost-effectiveness of these techniques. Future studies should focus on larger clinical cohorts to validate these findings.

High Efficiency Producing Technology Applied in Metal Optical Lens by 3D Wax Printing Combined with Investment Casting

3D printing technology can easily and quickly produce small batch models and full-size parts, which has obvious and important benefits in shortening development time. Since metals exhibit excellent mechanical strength and high wear resistance, metal additive manufacturing (MAM) is a popular technology for making metal parts. However, metal powders and 3D-printing machines are costly, which increases the difficulty of achieving mass production through MAM. In this study, the 3D wax printing and investment casting (WPIC) approach was developed to manufacture high-quality metal optical lenses with high efficiency and low cost. The manufactured lenses had a diameter of 38.1 mm, two radii of curvature (15 and 90 mm), and a cooling channel. These lenses were manufactured through 3D printing by using wax patterns produced through investment casting. The manufacturing efficiency and machining accuracy of the lenses produced using the proposed method were compared with those of lenses produced through MAM and investment casting. The results indicated that the total costs of manufacturing an optical lens through MAM and investment casting were nine and eight times greater, respectively than that of manufacturing an optical lens through WPIC. In addition, the surface roughness of metal lenses manufactured through WPIC was 45% lower than that of lenses manufactured through MAM. Finally, the time required to manufacture 50 metal lenses was only 15 days when WPIC was used; the corresponding time was 25 days and 6 months when MAM and investment casting were used, respectively. According to the above-mentioned results, the WPIC process has excellent advantages in product manufacturing cost and developing schedule over MAM and traditional methods of investment casting.

Influence of Silver Nanoparticle Integration on the Composition and Surface Properties of Acrylic Dental Resins Employed in Temporary Bridges

Background: Recognized widely for its irreversible effects, periodontal disease stands as one of the most prevalent conditions, particularly emphasizing the potential for permanent damage caused by gingivitis, extending to encompass the entirety of the supportive complex, including the connective tissue and alveolar bone. Patients necessitating comprehensive periodontal and prosthetic treatments require an interdisciplinary approach, involving the coordination of pre-treatment procedures and appropriate prosthetic strategies. The adoption of advanced materials and techniques can prove beneficial in addressing complex dental issues. (2) Methods: Forty specimens were prepared using the prescribed procedure, with 20 acting as controls and the other 20 integrating AgNPs. The initial step involved crafting wax patterns of distinct shapes: dumbbell shapes for tensile testing and rectangular shapes for roughness assessments. These dimensions were aligned with ASTM D-638 and ISO 527-2 standards and adjusted to match the specifications of the analysis device for mechanical properties. (3) Results: In this case, the results indicate minimal differences in heat-curing acrylic resins compared to the control samples at a 5% concentration. However, notable disparities arise at concentrations of 10% and 20%. (4) Conclusions: Temporary prosthetic constructions are essential for preventing functional imbalances and complications. Incorporating AgNPs at a 5% concentration maintains mechanical properties while providing antibacterial effects for long-term interim prosthodontic restorations. Higher nanoparticle concentrations may reduce resin mechanical properties without affecting material surface condition

The effect of pattern fabrication methods on the marginal fit of three‐unit implant‐supported frameworks: An experimental study

AbstractObjectiveThis in vitro study aimed to evaluate and compare the marginal fit of three‐unit implant‐supported frameworks fabricated based on conventionally hand‐waxed, milled, and three‐dimensional (3D) printed patterns.Materials and MethodsTwo fixture analogs were placed in the mandibular right first premolar and first molar region of the dentiform and two prefabricated abutments were secured in the fixture analogs. Thirty three‐unit wax patterns were fabricated through conventional, milling, and 3D printing techniques (n = 10 per group). After casting, the vertical marginal gaps of two abutments for each restoration were measured by using an optical microscope on 16 points around the finish line at ×80 magnification. The data were analysed by using one‐way ANOVA and Tukey's post hoc test (α = 0.05).ResultsThe marginal gap was found to be significantly different among the three manufacturing methods (p < 0.001) and between each pair (p < 0.001). The 3D printing group had a significantly lower marginal gap than the milling (p < 0.001) and the conventional group (p < 0.001) in the first premolar and first molar regions and the mean of the two. The marginal gap in the milling group was significantly lower than that of the conventional group (p < 0.001) in the first premolar and first molar regions and the mean of the two.ConclusionThe marginal fit of the frameworks was the best in the 3D printing method, followed by the milling, and finally the conventional method. However, the fit accuracy in all three methods remained within the clinically acceptable range (<120 μm).

Comparison of the Marginal and Internal Fit of Ceramic Laminate Veneers Fabricated with Four Different Computer-Aided Manufacturing Techniques.

Purpose: The improvement of computer-aided design and computer-aided manufacturing (CAD/CAM) has changed the methods of fabricating laminate veneers. The objectives of this study were to evaluate the marginal and internal fit of ceramic veneers manufactured with different CAD/CAM techniques. Materials and methods: A metal die was made by copying a prepared plastic maxillary central right incisor and scanned for designing a laminate veneer. One hundred laminate veneers were made with four different CAD/CAM techniques (n=25), including milled lithium disilicate (MLD), heat-pressed lithium disilicate with 3-dimensional (3D) printed wax patterns (PLD), milled zirconia (MZ), and 3Dprinted zirconia (PZ). The virtual marginal and internal fit of fabricated veneers was evaluated with digital crown fitting software. The actual marginal and internal fit was measured with the silicone replica method under a digital microscope. The measured data were analyzed using the one-way analysis of variance and the Turkey test. Results: There were significant differences in marginal and internal fit (P < 0.001) among manufacturing techniques. Both the virtual and actual marginal and internal gaps were higher in the PLD and PZ groups compared to the MLD and MZ groups. Conclusion: All four CAD/CAM techniques of manufacturing veneers, that is, milled lithium disilicate, heat-pressed lithium disilicate with 3D-printed wax patterns, milled zirconia, and 3D-printed zirconia, have clinically acceptable marginal and internal fit. Milled zirconia and lithium disilicate veneers demonstrated superior marginal and internal fit compared to 3D-printed zirconia and heat-pressed lithium disilicate veneers with 3D-printed wax patterns.

Wax Patterns, Textural Properties, and Quality Attributes of Two Eggplant (Solanum melongena L.) Cultivars during Storage

Two eggplant cultivars (Brigitte and Dalong) were stored under ambient conditions for 8 days to examine the postharvest quality and shelf life. Results indicated that the respiration rate, firmness and springiness, and nutritional quality of both eggplant cultivars decreased with the extension of shelf life. On the contrary, opposite trends were observed in weight loss, gumminess, and chewiness of eggplant fruits. In addition, the weight loss of ‘Brigitte’ eggplant fruits was 3.3% and 6.9% lower compared with ‘Dalong’ eggplant fruits at 4 and 8 days after storage. Thicknesses of epidermal cells and the stratum corneum, the epicuticular wax content of ‘Brigitte eggplant fruits increased by 42.9%, 766.7%, and 58.8% compared with ‘Dalong’ eggplant fruits, respectively, with a concomitant increase in the dense wax layer structure. In conclusion, the storage tolerance of ‘Brigitte’ eggplant fruits was higher than that of ‘Dalong’ eggplant fruits due to the higher epicuticular wax content and dense wax layer structure.

Effect of Composition and Pouring Temperature of Cu-Sn on Fluidity and Mechanical Properties of Investment Casting

The composition and pouring temperature are important parameters in metal casting. Many cast product failures are caused by ignorance of the influence of both. This research aims to determine the effect of adding tin composition and pouring temperature on fluidity, microstructure and mechanical properties including tensile strength and hardness of tin bronze (Cu-Sn). The Cu-Sn is widely used as employed in the research is Cu (20, 22 and 24) wt.%Sn alloy using the investment casting method. Variations in pouring temperature treatment TS1 = 1000°C and TS2 = 1100°C. The mold for the fluidity test is made with a wax pattern then coated in clay. The mold dimensions are 400 mm long with mold cavity variations of 1.5, 2, 3, 4, 5 mm. Several parameters: increasing the pouring temperature, adding tin composition, decreasing the temperature gradient between the molten metal and the mold walls result in a decrease in the solidification rate which can increase fluidity. The α + δ phase transition to β and γ intermetallic phases decreases fluidity at &amp;gt;22wt.%Sn. The columnar dendrite microstructure increases with the addition of tin composition and pouring temperature. The mechanical properties of tensile strength decrease, hardness increases and the alloy becomes more brittle with increasing tin composition.

Fabrication of sacrificial wax pattern through large-scale fused granulated fabrication (FGF-AM) hybrid manufacturing system

Fabrication of sacrificial wax pattern through large-scale fused granulated fabrication (FGF-AM) hybrid manufacturing system

Effect of pattern fabrication methods on retentive strength in three‐unit implant‐supported frameworks: A comparative analysis

AbstractObjectiveGiven the significant role of retention in the long‐term success of implant‐supported prostheses, this study aimed to compare the retentive strength of three‐unit implant‐supported frameworks manufactured using the conventional, subtractive milling, and 3D printing methods.Materials and MethodsIn this in vitro study, two fixture analogs were placed in the mandibular right first premolar and first molar region of a Dentiform model, and two prefabricated abutments were secured in the fixture analogs. A total of 27 three‐unit frameworks were fabricated utilizing wax patterns prepared through conventional, milling, and 3D printing techniques (n = 9 per group). The frameworks were cemented with zinc oxide eugenol and subjected to thermocycling. The retentive strength of each specimen was evaluated through a pull‐out test conducted with a universal testing machine. The data were analysed using one‐way ANOVA and Tukey's post hoc test (p &lt; 0.05).ResultsThe three groups were found to be significantly different (p = 0.01). While the 3D printing and milling groups were not significantly different (p = 0.99), they yielded significantly higher retentive strength compare to the conventional group (p = 0.02 for 3D printing and p = 0.03 for milling group).ConclusionThe utilization of 3D printing and milling technique for wax pattern preparation significantly increased the retention of the implant‐supported framework, with no statistically significant difference between the two methods.

An innovative approach for lid design for rehabilitation of maxillary oncological defect using hollow bulb obturator

BackgroundPost Maxillectomy, prosthodontic treatment modalities include surgical obturator, interim obturator and followed by definitive obturator. The surgical and interim obturator serves the purpose of providing a matrix on which surgical packing can be placed, reduces the contamination during wound healing, facilitates speech and permits deglutition and lessens the psychological impact of surgery. Local drug delivery techniques at the surgical site and the fabricated prosthesis have an impact on the targeted tissue. ObjectivesTo design a hollow bulb obturator with a detachable lid with attachments in the palatal surface of the obturator and to facilitate local drug delivery. MethodsDuplication of patient's maxillectomy cast, pre-shaped plaster bolus was incorporated inside the defect space to create the hollow space. After which a wax pattern was fabricated and acrylized. Wax template of the lid design was made and acrylized incorporating pins. ResultThe weight of the prosthesis is reduced. Due to the lesser weight of the prosthesis retention and physiologic function increases. The decrease in pressure to the surrounding tissue aids in deglutition and encourages the regeneration of tissue. The fabricated lid appears stable and retentive, which can be easily removed and placed back according to the need. ConclusionLocal drug delivery techniques at the surgical site and the fabricated prosthesis has an impact on the targeted tissue.The ability of the drug to reach the appropriate anatomic region will always be important, and has been the subject of much research in the past 5 years. Modified hollow bulb of the obturator in this research can aid in local drug delivery in surgical and interim obturators avoiding the removal of the obturator as the whole.

Comparing the trueness of 3D printing and conventional casting for the fabrication of removable partial denture metal frameworks for patients with different palatal vault depths: An in vitro study

Statement of problemThe success of a removable partial denture depends on its fit, and, with conventional casting, the framework is more distorted in patients with a deep palatal vault. Questions remain about whether the three-dimensional (3D) printing technique for fabricating a framework can improve the accuracy of fit for these patients. PurposeThe purpose of this in vitro study was to compare the trueness of metal frameworks fabricated by selective laser melting, 3D printing pattern casting, and conventional casting for different palatal vault depths. Material and methodsA total of 30 partially edentulous maxillary casts were custom-made in 15 medium and 15 deep palatal vaults. All stone casts were scanned as reference models in digital files. For the medium palatal vault casts, Co-Cr frameworks of the conventional casting (CON) group (n=5) were fabricated with the lost wax technique. For the 3D printing pattern casting (PPC) group (n=5), wax patterns of the framework were printed, followed by metal casting. The frameworks created for the selective laser melting (SLM) group (n=5) were printed directly by using the SLM machine. The same procedures were followed for the deep palatal vault group. All the metal frameworks were scanned and superimposed with the reference casts by using the Geomagic Control X software program. Discrepancies were measured as mean ±standard deviation (trueness), and the data were statistically analyzed with a 2-way ANOVA test to evaluate the interaction of 2 independent factors (fabrication techniques and palatal vault depths) on a trueness outcome (α=.05). ResultsThe lowest mean ±standard deviation value was 0.092 ±0.023 mm, found from the SLM framework with deep palatal vault group, while the highest value was 0.194 ±0.017 mm, found from the CON framework with deep palatal vault group. Different fabrication techniques interacted with different palatal vault depths in terms of trueness (P<.05); however, no significant differences were observed in the medium palatal vault groups (P>.05). Additionally, color mapping demonstrated the gaps of metal frameworks among the 6 groups. ConclusionsWith the conventional casting technique, the accuracy of the metal framework was affected by the depth of the palate. For medium palatal vaults, all fabricated frameworks had clinically acceptable fit. For deep palatal vaults, the SLM frameworks showed the lowest discrepancy. As a result, the SLM technique is advised for fabricating a better-fitting metal framework for patients with a deep palatal vault.

A multi-objective optimization based on machine learning for dimension precision of wax pattern in turbine blade manufacturing

A multi-objective optimization based on machine learning for dimension precision of wax pattern in turbine blade manufacturing

A novel method for evaluating thermal expansion forces during dewaxing of investment casting and 3D-printing waxes

This study proposes a novel method for the evaluation of expansion forces that occur during the heating of IC (investment casting) waxes with the help of a rheometer. Thermal expansion of the IC wax patterns is the main reason that causes ceramic shell failure during the dewaxing process. The technique is based on the measurement of normal forces that develop in the measuring system of the rotational rheometer during solidification of wax samples. These forces are created as a result of shrinkage of thermally expanded wax samples. To assess the efficiency of the proposed method, three types of commercially available waxes and one 3D-printable wax have been tested and compared. According to research findings, the proposed method can be prescribed as an efficient procedure for the evaluation of expansion forces that develop during wax heating, especially for waxes that have low viscosity properties. It was observed that machinable wax produced the highest value of normal load equivalent to 86 N while the IC and 3D-printing wax generated 18.8 and 36.3 N respectively. Moreover, it was discovered that additively manufactured wax patterns perform considerably better compared to their casted analogs during dewaxing processes

Evaluation of the trueness and precision of ceramic laminate veneers fabricated with four computer-aided manufacturing methods

The accuracy of computer-aided design/computer-aided manufacturing (CAD/CAM) methods plays an important role in the clinical success of ceramic veneers. This study aimed to evaluate the impact of different CAD/CAM methods, including subtractive, hybrid, and additive manufacturing, on the trueness and precision of ceramic veneers. A typodont central incisor was prepared for a laminate veneer, followed by the design of a veneer with CAD software. Ceramic veneers were fabricated with four different CAD/CAM methods, including milled lithium disilicate, pressed lithium disilicate with three-dimensional (3D) printed wax patterns, milled zirconia, and 3D-printed zirconia. All veneers were scanned and imported to 3D inspection software for trueness and precision evaluation. Laminate veneers fabricated with all investigated methods exhibited clinically acceptable trueness and precision. Pressed lithium disilicate veneers from 3D-printed wax patterns and 3D-printed zirconia veneers showed lower precision of the fitting surfaces compared to their milled counterparts.

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

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. 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. 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). 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. 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.

Role of silicon carbide in enhancing microwave hybrid heating and reducing dewaxing time in investment casting

Mould cracking is a common problem in investment casting (IC) that occurs during the dewaxing process, which is caused by the difference in thermal expansion between the wax pattern and the ceramic mould. Therefore, appropriate modifications to the mould, waxes and hybrid heating of the materials are proposed to address this problem. This study aims to investigate the effects of silicon carbide (SiC) addition on dewaxing time and mould structural defect in two different waxes (HYFILL B289 MOD S and SIVUCH L1203) under microwave hybrid heating. For the mould fabrication, stucco (Al2O3-SiO3) was added with various amounts of SiC to improve microwave heat absorption capabilities. The modified stucco was applied on layers 3–6 to ensure that the mould was more durable and suited for the casting process. The thermal expansion of the waxes and the ceramic mould was evaluated to determine its thermal expansion mismatch. The density, porosity, thermal conductivity, and dielectric properties were characterized to evaluate the properties of modified green mould. The results showed that SIVUCH L1203 wax outperformed HYFILL B289 MOD S wax, in obtaining a crack-free ceramic investment mould with a clean internal surface. This superiority is attributed to the exceptional thermal and absorption properties of the SIVUCH L1203 wax. Furthermore, the incorporation of SiC played a pivotal role in enhancing the hybrid heating process while maintaining the density and porosity of the green moulds. This was evident by the remarkable reduction of dewaxing time by 62% with 7.5% of SiC addition, which also contributed toward improving energy savings and sustainability.

Technological considerations regarding the use of CAD-CAM systems in the metal substructure design of some metal-ceramic prosthetic restoration

Abstract In this material, two clinical cases are described, regarding the use of CAD-CAM technology for producing the wax pattern of the metal substructure for a fixed prosthetic restoration. In fact, in these cases, it is about making a digital design and milling from a block of wax the patterns of future fixed metal-ceramic prosthetic restorations.

Enhancing the Cooling Efficiency of Aluminum-Filled Epoxy Resin Rapid Tool by Changing Inner Surface Roughness of Cooling Channels.

In low-pressure wax injection molding, cooling time refers to the period during which the molten plastic inside the mold solidifies and cools down to a temperature where it can be safely ejected without deformation. However, cooling efficiency for the mass production of injection-molded wax patterns is crucial. This work aims to investigate the impact of varying surface roughness on the inner walls of the cooling channel on the cooling efficiency of an aluminum-filled epoxy resin rapid tool. It was found that the cooling time for the injection-molded products can be determined by the surface roughness according to the proposed prediction equation. Employing fiber laser processing on high-speed steel rods allows for the creation of microstructures with different surface roughness levels. Results demonstrate a clear link between the surface roughness of cooling channel walls and cooling time for molded wax patterns. Employing an aluminum-filled epoxy resin rapid tool with a surface roughness of 4.9 µm for low-pressure wax injection molding can save time, with a cooling efficiency improvement of approximately 34%. Utilizing an aluminum-filled epoxy resin rapid tool with a surface roughness of 4.9 µm on the inner walls of the cooling channel can save the cooling time by up to approximately 60%. These findings underscore the significant role of cooling channel surface roughness in optimizing injection molding processes for enhanced efficiency.