Stress Distribution on Prepared Tooth With Shoulder and Radial Shoulder Margin to Receive Crowns of Three Different Materials: A Finite Element Analysis.

Aim and background This study aims to determine the stress distribution on the prepared tooth at the margins with shoulder and radial shoulder finish lines when an occlusal load of 300N was applied to ceramic, zirconia, and polyether ether ketone (PEEK) crowns. Materials and methods Six models of mandibular first molar teeth were fabricated. The tooth models were subdivided into two groups with shoulder and radial shoulder margins, respectively (n = 18). The teeth were restored with three different prosthetic crown materials (ceramic, zirconia, and PEEK). To simulate the typical forces experienced by a prosthetic crown material in a lower posterior tooth during chewing and biting, an occlusal load of 300N was applied to each of the samples, and the maximum principal stress (Pmax) and von Mises stress were calculated, respectively. These samples were then compared and evaluated to determine the material best suited as a prosthetic crown material of choice for a lower posterior tooth. Results Among the materials used, the maximum principal stress value was the least in PEEK crowns. The von Mises stress value was highest for the zirconia crown with shoulder margin and was least for the PEEK crown with a similar margin. Conclusion PEEK as a crown material was found to be a better choice for lower posterior teeth as there was the least maximum principal stress at the margin, irrespective of either shoulder or radial shoulder finish line used.

Magnet retained cheek plumper to enhance denture esthetics: case reports.

Handicap due to the loss of teeth in patients can be severe due to the impairment of masticatory function and facial disfigurement leading to negative psychological impact on the individual. To combat this, apart from the regular measures of positioning the teeth to obtain lip support, excellent denture esthetics can be achieved by providing additional support to the slumped tissues. This clinical report highlights a technique to provide support for sunken cheeks using detachable acrylic cheek plumpers, retained using iron-neodymium close-field magnets. The use of these magnets is a modification from the conventional technique of supporting the slumped tissues.

Addition Silicone Impressions in Fixed Prosthodontics: Clinical Standpoints.

Addition silicones have revolutionized the field of fixed prosthodontics because of their dimensional stability, sufficient tear strength and excellent detail reproduction. This review study aims to provide a detailed description of the essential variables to be taken into account during the process of making addition silicone impressions in fixed prosthodontics. These variables include the selection of appropriate tray type, size, and fabrication; the use of tray adhesive; gingival displacement techniques; manipulation of the impression material; the choice of the impression material's viscosity; impression techniques; and the proper insertion, removal, disinfection, and pouring of the cast. Additionally, this review aims to help doctors produce high-quality impressions by empowering them to critically assess the impressions to spot mistakes and motivating them to redo impressions that have serious problems before submitting them to the laboratory.

Perceptions and preferences on denture marking in an Indian sample.

AIM: Denture marking is useful in institutional settings and post-mortem identification. Numerous markers have been developed, and their advantages and limitations assessed previously; however, patient perception to denture marking is paramount. We evaluated this in an Indian sample and also gauged their preference for different markers. MATERIALS AND METHODS: One-hundred and one edentulous patients seeking prosthodontic treatment in our institution were shown four denture markers (stainless steel matrix band, paper strip with name inscribed on it, patient photograph and optically readable laminated bar code) and asked whether they wanted similar markers in their dentures; patients were also asked to rank the markers based on preference and indicate their satisfaction with it. RESULTS: Approximately two-thirds of patients (65/101) were uninterested in getting their dentures marked; among the 36 who agreed, 10 preferred the stainless steel band followed by photographs (9), paper strip (6) and bar code (2); nine gave multiple responses and were excluded from analyses. Sixteen patients expressed dissatisfaction with the photographic marker and bar code, while this number reduced for the stainless steel band (13) and paper strip (10). CONCLUSIONS: The results are in contrast to European studies wherein the majority of patients agreed to denture marking, indicating patient background (e.g. education level) may affect perception to denture marking; amongst those who agreed to marking, most preferred, or were satisfied with, the stainless steel and paper strip markers over photographic marker and a complex method such as bar-coding, implying that simple methods harbouring basic patient information may suffice in the Indian context.

Usefulness of patient photograph as a marker for identifying denture-wearers in India.

AIM: Denture marking has been recommended for identifying the edentulous, both in day-to-day recognition when dentures are misplaced as well as in forensic scenarios. The purpose of this study was to test the use of patient photographs as a denture marker and to compare it with conventional marking systems as well as discussing its suitability in the Indian context. MATERIAL AND METHODS: A photograph of the patient was taken and compared with a metal matrix band and optically readable laminated bar code in terms of preparation, ease of incorporation into the denture, readability following denture fabrication and changes on exposure to high temperatures (200-1300 °C). RESULTS: The photograph and metal matrix band were easy to prepare and incorporate, but the bar code was less so; no differences, however, were appreciable with regard to readability of the three markers. Fire resistance of the photographic marker (280 °C) and bar code (200 °C) was considerably lower to that of the metal marker (1050 °C). CONCLUSIONS: The major advantage of the photographic marker is that identity is easily ascertained by lay persons with the unassisted eye (bar codes require a hand-held reading device); photographic markers are also relevant in the Indian context where one-third of the population is illiterate and diverse scripts are used across the country, making interpretation of written data challenging at times. This allows for photographic markers' routine use in residential and hospital set-ups. Although the photographic marker has low fire resistance, it may be useful in forensic contexts since dentures retained in the mouth are well-protected by the oro-facial tissues and may survive incineration.