How to cite this article:
Omori T, Sato Y, Kitagawa N, Shimodaira O, Isobe A, Takamathu N, Tanaka S. Effects of Palatal Plate Loading on Mucosa Development in Three-dimensional Finite Element Models. Int J Prosthodont Restor Dent 2020; 10 (2):50-56.
Aim: The aim of this study was to verify the stress distribution associated with the thickness and elastic modulus of the palatal mucosa by three-dimensional finite element models of a dentulous subject and a pseudopalatal plate at pain onset after loading with a clenching force.
Materials and methods: The subject was a 35-year-old man with a dentulous jaw. Fourteen measurement sites were designated on the subject\'s palatal mucosa, and the mucosal thickness and load amount at pain onset were measured at each site with an ultrasonic thickness gauge and a strain gauge. These data were used to calculate the elastic modulus. Next, a pseudopalatal plate was created from scanning resin and photographed using cone-beam computed tomography. Three-dimensional finite element analysis (FEA) software was used to construct the pseudopalatal plate part. In addition, measurements of the actual mucosal thickness were added as elements to the mucosal surface of the pseudopalatal plate part. It was configured with the elastic modulus values of the palatal mucosa part. The load was the clenching force at the onset of pain (111 N cm) based on a previous study.
Results: The conventional and optimized models showed greatly different stress distributions. In addition, thick areas of the palatal mucosa were more susceptible to influence from the elastic modulus, while in the thin areas, stress generation was not related to the elastic modulus.
Conclusion: Differences in thickness have a greater impact on stress distribution than differences in elastic modulus. Thus, the results demonstrated the importance of building a model based on actual measurements of the thickness of a subject\'s palatal mucosa.
How to cite this article:
Agarwal SK, Kumar M, Singhal R, Singh A, Kalpana K. A Comparative Evaluation for Retention of Maxillary Complete Denture Using Different Commercially Available Denture Adhesives: An In Vivo Study. Int J Prosthodont Restor Dent 2020; 10 (2):57-61.
Aim: To evaluate and compare the effects of different denture adhesives which are available commercially on retention of maxillary complete denture.
Materials and methods: Thirty edentulous patients were selected with well-formed ridges without any undercuts. Denture bases made up of heat cure acrylic resin were fabricated on the master cast by a compression molding technique. A custom-made apparatus was used to test the retention of maxillary denture bases using three test denture adhesives. Readings were noted and were statistically analyzed.
Results: Retention of maxillary complete denture was found to be the highest in Supergrip powder (7.04 ± 0.62) followed by Seabond cushion (6.21 ± 0.42) and Supergrip cream (4.91 ± 0.36), and the lowest in control. Post hoc test showed a significant difference between different pairs of denture adhesives and controls as p = 0.0001.
Conclusion: This study revealed that Fixon Supergrip powder showed maximum retention.
Chitha PP Sabarigirinathan
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Sripriya S, Vinayagavel K, Meenakshi A, Sabarigirinathan CP. Evaluation of Stress Distribution in Implants Used to Retain Auricular Prosthesis with V-shaped and Reverse Buttress Thread Design by Three-dimensional Finite Element Analysis. Int J Prosthodont Restor Dent 2020; 10 (2):62-71.
Aim: To compare the stress distribution in the implant used to retain auricular prosthesis with V-shaped thread and reverse buttress thread design.
Materials and methods: Commercially available implant marketed by southern implant with V-shaped thread was taken as the control group. This parameter was taken to manufacture indigenous implant with reverse buttress thread design. Both the indigenous implant and commercially implant were scanned by noncontact profilometer using optical comparator (Deltronics Corp, USA). These data were imported into Pro/E wildfire 4.0 software (PTC, USA) for the creation of a three-dimensional (3D) model. Human skull was scanned using the 3D white light scanner, and these data were converted into surface model with the help of computer-aided design and drafting (CAD)/computer-aided manufacturing (CAM)/computer-aided engineering (CAE) tools. These 3D cloud data were imported into CATIA software for mesh generation. The implants were placed in the specified location in the temporal bone. The next step was loading on the implant 10 N axial loading on the center of the implant and moment on the same area of 100 N mm was done. The effect of load distribution with and without bar connection was assessed.
Results: The statistical significance of the data within the group was assessed using mean and standard deviation and that between the group was assessed using Levene\'s test for variance and t test for mean. The stress distribution is more at the flange and less at the end and considerably reduced on connection with bar.
Conclusion: The presence of the flange in the craniofacial implant decides the stress distribution and is not by the shape of the thread.
Ajinkya S Kirad,
Aamir Z Godil,
Arshi I Kazi,
How to cite this article:
Kirad AS, Dugal R, Godil AZ, Kazi AI, Attarwala T. Evaluation of Flexural and Impact Strength of CAD–CAM and Two Different Conventional Denture Base Resins: An In Vitro Study. Int J Prosthodont Restor Dent 2020; 10 (2):72-76.
Aim: To carry out a comparative evaluation of flexural strength and impact strength of computer-aided design/computer-aided manufacturing (CAD/CAM) denture base resin with conventional heat cure resin fabricated by two different techniques.
Materials and methods: The study was carried out in three groups based on the manufacturing process of the dentures: Group I (n = 30)—control group containing specimens fabricated by conventional pressure-pack technique (polymer and monomer—powder and liquid, (DPI, Mumbai, India)); Group II (n = 30)—specimens fabricated using injection molding technique (SR—Ivocap High Impact, Ivoclar Vivadent, Liechtenstein); and Group III (n = 30)—specimens fabricated using CAD/CAM technology (Bloomden™, China). The values for flexural strength of each specimen were measured using a universal testing machine by a three-point bending test. Impact strength testing of the samples was done on the Izod impact testing machine with a pendulum of S2 scale in air at 23 ± 2°C. The mean values of the flexural strength and impact strength were calculated by the one-way ANOVA test and intergroup comparison was done using Tukey pairwise comparisons.
Results: The flexural strength (FS) and impact strength (IS) of CAD/CAM (FS = 93.16 ± 5.46 MPa and IS = 15.625 ± 2.512 kJ/m2) samples were highest followed by injection molded samples (FS = 84.82 ± 5.30 MPa and IS = 12.511 ± 2.908 kJ/m2) and least for compression molded control group (FS = 74.70 ± 5.02 MPa and IS = 8.446 ± 0.937 kJ/m2).
Conclusion: CAD/CAM denture base resins have the highest flexural and impact strength compared to injection molded and compression molded heat cure denture base resins.
Constant risk of contact and proximity to oral cavity and the production of aerosol have increased the risk of coronavirus disease 2019 (COVID-19) among dentists. Transmission of coronavirus (CoV) is through respiratory droplets, close contact, or aerosols. Coronaviruses are lipid bilayer enveloped viruses with the viral structure formed primarily of structural proteins having affinity toward the angiotensin-converting enzyme 2 receptors, which are found abundantly on the mucosa of tongue. These facts have led to categorization of dentistry as a very high exposure risk job with high potential for exposure to COVID-19. Due to the absence of vaccine till date, it is crucial to scrutinize and refine preventive maneuver and to implement strict and efficient infection control protocols to prevent cross infection of COVID-19 among dentists, dental team, and patients in the clinical setup. Based on the existing guidelines and the recently initiated guidelines from the Centers for Disease Control and Prevention and World Health Organization, this study provides infection control strategies in the field of dentistry in general and in prosthodontics in particular.
The success of the endodontically treated tooth is highly dependent on the quality of the coronal restoration. The placement of a post is recommended if the total amount of the residual tooth structure is not sufficient to support a core made of a plastic material. Even though uncommon, there might be possibility that patients came with a fractured core during the session of bridge cementation. Retrofitting the crown or bridge on a fractured core might be a better option, and various practitioners had performed this method successfully. This technique explains the production of vacuum-formed thermoplastic template adapted on a die stone master cast to make up the composite resin core of fractured tooth in the original shape.
Methamphetamine also popularly known as meth crystal, crystal, or ice is a highly addictive recreational drug that is a central nervous system stimulant. Even though the drug is banned, availability in the illegal black market because of its low cost and easy production technique makes it one of the most commonly used drugs by the addicts. Methamphetamine and amphetamine-type stimulants (ATS) like Captagon which contains fenethylline is chemically related to amphetamine, are powerful psychostimulant, produce an intense rush of pleasure, prolonged sense of euphoria, hyperactivity, increased awareness and hallucinations, convulsions and aggressiveness. Literature review shows patients with drug addiction have a typically dark, leathery distinctive type of rampant caries called methamphetamine-induced caries (MIC) along with xerostomia, gingival inflammation, and poor oral hygiene. Knowledge of methamphetamine drug abuse and its effect on dentition puts the dental practitioners in a unique position in identifying the patients with potential drug abuse. Dentists can play an important role in not only early detection but also can help patients in the cessation of the drug abuse.