Lingual Position of the Wrought Wire Clasp for Removable Partial Dentures Esthetic

BackgroundThe esthetic repair of a removable partial appliance is a critical function that determines the success of the therapy. The most challenging challenge is to achieve While maintaining stability, retention, and protect teeth's health, optimal esthetics is achieved. Removable partial prosthesis is an odious therapeutic option that we still have to use in some circumstances and is a common procedure. However, these patients anticipate receiving a prosthesis. ObjectiveTo determine wrought wire clasp for removable partial dentures for esthetic. Materials and MethodsAfter taking impressions (primary and final) for the maxilla or the mandible of many patients, stone castings were pouring in class III (dental stone) using a 30 ml water to 100 g powder ratio. For the installation of prosthetic teeth, a uniform denture base plate wax template was made on each stone cast, and lingual clasps were inserted around the abutment teeth. Dental plaster is used to flake the lower piece of the traditional brass flasks (class II). The denture foundation was meticulously deflasked, after the curing cycle, the surplus is removed and the denture surface is polished. ResultsDentures that have been treated using this method have a high level of retention. Excellent aesthetics, make it more sanitary and dentures with the lingual clasps method are more comfortable for the patient. ConclusionDentures made with this procedure have better retention, a better esthetic, are good hygienic, and are high comfortable for the patient than dentures made using labial clasps.

Multi-Objective Optimisation of Curing Cycle of Thick Aramid Fibre/Epoxy Composite Laminates

Aramid fibre-reinforced epoxy composites (AF/EP) are promising materials in the aerospace, transportation, and civil fields owing to their high strength, high modulus, and light weight. Thick composite laminates are gradually being applied to large composite structures such as wind turbine blades. During curing, temperature overheating is a common problem in thick composites, which leads to matrix degradation, thermal residual stresses, and uneven curing. This paper proposes a signal-to-noise ratio (SNR) method to optimise the curing cycle of thick AF/EP laminates and reduce the overheating temperature. During curing, the temperature and strain evolution in a thick AF/EP laminate were monitored using fibre Bragg grating sensors. The effects of the curing factors on the overheating temperature of the thick AF/EP laminate were evaluated using the Taguchi method and predicted via the SNR method and analysis of variance. The results indicate that the dwelling temperature is the main factor affecting the overheating temperature. The optimal curing cycle involves an overheating temperature of 192.72 °C, which constitutes an error of 2.58% compared to the SNR method predictions. Additionally, in comparison to the initial curing cycle, the overshoot temperature in the optimised curing cycle was reduced by 58.48 °C, representing a reduction ratio of 23.28%.

Effect of flask closure method on occlusal vertical dimension of complete upper and lower dentures

The movement of teeth during processing of complete dentures disturbs the harmonious occlusal scheme established at the final wax try-in stage. Aims and objectives: to investigate the effect of RS flask closure on occlusal vertical dimensions of complete dentures. The mean occlusal vertical dimension of complete maxillary and mandibular dentures fabricated by the conventional flask closure were measured and compared with that of dentures fabricated by RS flask closure. Design: A pre-test post-test control group experimental design. Methods: Thirty sets of complete maxillary and mandibular wax trial dentures were randomly assigned to experimental groups. Fifteen sets were assigned to conventional flask closure and the remainder to RS flask closure. Compression molding with a long curing cycle was performed for the processing of the dentures. Pre-processing and post-processing occlusal vertical dimensions were determined. Results: The mean occlusal vertical dimensions of wax trial dentures assigned to either group were similar. The data produced substantial evidence to reject the null hypothesis that the post-processing mean occlusal vertical dimensions of both groups were equal. Conclusion: The occlusal vertical dimensions produced by dentures clamped by the RS flask closure were significantly less than those produced by dentures clamped by the conventional flask closure.

Influence of resin curing cycle on the deformation of filament wound composites by in situ strain monitoring

The residual stress of metal liners wrapped by composite materials has a significant influence on the service performance of rotating parts, such as flywheel rotors and motor jackets. However, the deformation of the liners, the flow of resins, and the temperature variation during the winding process make it difficult to predict and control this residual stress. In this paper, the process-induced strains were monitored online by a strain gauge with the help of a wireless strain meter. The evolution of this strain during the manufacturing process was fully discussed. A rapid curing resin system was used and its curing properties were tested by differential scanning calorimetry. The mechanical properties of the resin matrix and its composite were characterized. The effect of the curing cycle on the evolution of the residual strain was discussed in detail through comparative experiments. The experimental results show that the use of infrared radiation has a significant advantage regarding residual stress accumulation. This advantage is greater when carbon fiber is used than when glass fiber is used. The prestress in composites of glass fiber and carbon fiber increases by 5.9% and 41.7%, respectively, after cooling.

A Three-Dimensional Thermo-Chemical Characterization During the Whole Curing Cycle of a Carbon / Epoxy Prepreg

Mitigation of cure-induced defects in thermoset composite parts has always been a challenging problem for manufacturers especially when it comes to high dimensional accuracy of components. Thus, it is crucial to understand the evolution of the thermo-chemical properties of these materials during the totality of the curing cycle. In this paper, a new methodology is presented to characterize the process-induced strains throughout the cure. The investigation is based on the development of an existing laboratory bench named as PvT-HADDOC. The tests were performed on an interlayer toughened aerospace carbon/epoxy prepreg. Unidirectional laminate samples (105x105 mm2) of almost 6 mm of thickness were manufactured by hand lay-up then debulked at room temperature under full vacuum. The PvT-HADDOC device allows a manufacturing process following the recommended cure cycle of epoxy composites under 7 bars pressure and a temperature up to 180°C. It enables the measurements of the process-induced strains, simultaneously, along two directions: through-thickness and in-plane. Results show a complex behavior of an assumed unidirectional composite. It exhibits a temperature and time dependent compaction behavior through the thickness only. The measured thermal expansion coefficients are proved to be higher in the thickness direction for the uncured as well as for the cured state of the material. Most of the chemical shrinkage occurs along the thickness direction. This unexpected complexity is mainly attributed to the presence of interleaf layers of resin in the laminate structure. Thus, the investigated M21/IMA material is considered fully orthotropic.

Structural Batteries: A Review

Structural power composites stand out as a possible solution to the demands of the modern transportation system of more efficient and eco-friendly vehicles. Recent studies demonstrated the possibility to realize these components endowing high-performance composites with electrochemical properties. The aim of this paper is to present a systematic review of the recent developments on this more and more sensitive topic. Two main technologies will be covered here: (1) the integration of commercially available lithium-ion batteries in composite structures, and (2) the fabrication of carbon fiber-based multifunctional materials. The latter will be deeply analyzed, describing how the fibers and the polymeric matrices can be synergistically combined with ionic salts and cathodic materials to manufacture monolithic structural batteries. The main challenges faced by these emerging research fields are also addressed. Among them, the maximum allowable curing cycle for the embedded configuration and the realization that highly conductive structural electrolytes for the monolithic solution are noteworthy. This work also shows an overview of the multiphysics material models developed for these studies and provides a clue for a possible alternative configuration based on solid-state electrolytes.