The aim is to evaluate and compare the flexural strength of different provisional restorative materials reinforced with glass and polyethylene fibers. A total of 90 samples were prepared and divided into three groups based on the type of fiber reinforcement, unidirectional S-glass (Splint-It) and ultra-molecular weight polyethylene (Ribbond). Unreinforced samples served as control group. Again each group was subdivided into three subgroups based on type of provisional restorative resins, heats cure polymethyl methacrylate, self-cure poly methyl methacrylate and self-cure bis-acryl composite. Samples were loaded in a universal testing machine until fracture occurs. The mean flexural strengths (MPa) were subjected to the one-way ANOVA, followed by the Tukey-HSD test at a significance level of 0.001. The result shows all the fiber reinforced samples possessed greater strength than the control samples. In control samples, the heat cure poly methyl methacrylate resin (72.74 ± 2.28 MPa) had the greatest flexural strength, followed by self-cure bis-acryl composite (67.05 ± 2.35 MPa) and self-cure poly methyl methacrylate resin (52.88 ± 1.90 MPa). In both heat and self-cure poly methyl methacrylate resin, the polyethylene fiber reinforcement (96.00 ± 2.63 MPa, 86.17 ± 1.92 MPa) provides the greatest strength than glass fiber reinforcement (92.68 ± 1.58 MPa, 76.40 ± 2.11 MPa). In self-cure bis-acryl composite, the glass fiber (105.95 ± 3.07 MPa) shows better reinforcement than polyethylene fiber (99.41 ± 1.74 MPa).The fibers reinforcement increases the flexural strength of provisional restorative resins.
The aim was to evaluate the design parameters of dental implants shape, diameter and length on stress distribution by finite element analysis (FEA).The objectives of the study was to compare the influence of stress distribution in the implants of screw-vent tapered and parallel design by varying the implant diameter with a standard implant length. Six dental implant models have been simulated three-dimensionally. The influence of diameter and length on stress distribution was evaluated by Group I: for screw-vent tapered design (Zimmer Dental Implant Carlsbad, CA, USA) (1) Dental implant model with diameter 3.7 mm and length 13 mm. (2) Dental implant model with diameter 4.1 mm and length 13 mm. (3) Dental implant model with diameter 4.7 mm and length 13 mm. Group II: for parallel design (Zimmer Dental Implant Carlsbad, CA, USA) (4) Dental implant model with diameter 3.7 mm and length 13 mm. (5) Dental implant model with diameter 4.1 mm and length 13 mm. (6) Dental implant model with diameter 4.7 mm and length 13 mm. The 3-D model of the implant was created in the pro-e wildfire 4.0 software by giving various commands. This model was imported to the ANSYS software through IGES (initial graphic exchange specification) file for further analysis. All six models were loaded with a force of 17.1, 114.6 and 23.4 N in a lingual, an axial and disto-mesial direction respectively, simulating average masticatory force in a natural oblique direction, to analyze the stress distribution on these implants. The increase in implant diameter in Group I and Group II from 3.7 to 4.1 mm and from 4.1 to 4.7 mm with constant 13 mm length for screw-vent tapered and parallel design implant resulted in a reduction in maximum value of Von Mises stress in the bone surrounding the implant was statistically significant at 5% level done by student "t" test. The overall maximum value of Von Mises stress was decreased in parallel design implant diameter of 4.7 mm with constant length of 13 mm when compared to screw-vent tapered design implant samples. The results of the FEA computation depend on many individual factors including material properties, boundary conditions interface definition and also on the overall approach to the model. The results depicted that the tapered shape implant design exhibited higher stress levels in bone than the parallel shaped implant design which seemed to be distributing stresses more evenly. The application of a 3-D model simulation with the non-symmetric loading by the masticatory force on a dental implant resulted in a more satisfactory modeling of "clinical reality" than that achieved with 2-D models used in other studies.
The most challenging and appreciated area in the field of Prosthodontics is the rehabilitation of maxillary defects. Tumors of the head and neck are the common cause for acquired maxillofacial defects. Surgical consequences predispose the patient to hypernasal speech, fluid leakage into nasal cavity, impaired masticatory function, and cosmetic deformity. The Prosthodontists play a significant role in the intervention and improve the quality of life of such patients. The current article describes two clinical case reports of completely edentulous patients with acquired maxillary defects.
Patients who undergo segmental or hemi-mandibulectomy suffer from various postoperative problems in esthetics and function. The solution to such problem is providing a mandibular guidance appliance to correct mandibular deviation to resected side due to loss of muscle action on the affected side. This article describes the treatment of a female patient who underwent segmental mandibulectomy on right side secondary to adenoid cystic carcinoma of the base of tongue. An acrylic guidance appliance was constructed to help control the mandibular deviation and co-ordinate masticatory movements. The prosthesis was worn continuously by the patient for 1 month which corrected the occlusion on the left side. To compensate for the open-bite caused due to rotation of mandible following partial mandibulectomy, an overlay removable partial denture was given. The patient was satisfied with the improvement in esthetics and mastication.
Prosthesis refers to artificial replacement of an absent part of the human body. These prostheses help in psychological support of the patients and enhance their social acceptance. Complete or partial finger amputations are some of most frequently encountered forms of partial hand loss. Micro vascular reconstruction is the first choice of rehabilitation but when it is contraindicated, unavailable, unsuccessful or unaffordable, the prosthetic rehabilitation is an alternative for improving the psychological status of an individual. Most of these artificial prostheses make use of silicone. The present paper tries to combine aesthetics with function. The authors have created functionally active finger prosthesis with the help of electromechanical controls. The prosthesis is battery-powered, light-weight, and allows the user to regain complete control of flexion and extension movements of an artificial finger.
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