Flexural strength of polyether ether ketone high-performance polyether in comparison with base metal alloy and zirconia ceramic / Resistencia a la flexión del poliéter éter cetona poliéter de alto rendimiento en comparación con la aleación de metal base y la cerámica de circonio

Optimal flexural strength is a critical prerequisite for prosthetic frameworks. This study aimed to assess the flexural strength of polyether ether ketone (PEEK) polymer compared to a base metal alloy and high-strength Zirconia ceramic commonly used in prosthodontic treatments. Materials and Methods: In this in vitro, experimental study, 10 bar-shaped samples measuring 18×5×2mm were fabricated of each the PEEK polymer, nickel-chromium base metal alloy and zirconia ceramic. Half of the samples in each group were subjected to 5000 thermal cycles between 5°C - 55°C with 20 seconds of dwell time and 20 seconds of transfer time to simulate oral conditions. All samples then underwent three-point bending test. Two-way ANOVA followed by Tukey's test were applied to compare the mean flexural strength of the groups with and without thermocycling at 0.05 level of significance. Results: The flexural strength of base metal alloy, Zirconia and PEEK was 1387.70±45.50 MPa, 895.13±13.99 MPa and 192.10±5.37 MPa, respectively. The difference was significant among the groups (p<0.001). Thermocycling had no significant effect on the flexural strength of samples in any group (p=0.306). Conclusion: PEEK high-performance polymer had a lower flexural strength than base metal alloy and Zirconia ceramic, and its flexural strength was not affected by thermocycling. PEEK seems to be able to resist masticatory forces in the oral cavity pending further in vitro and clinical studies.

La resistencia a la flexión óptima es un requisito previo crítico para los marcos protésicos. Este estudio tuvo como objetivo evaluar la resistencia a la flexión del polímero de poliéter éter cetona (PEEK) en comparación con una aleación de metal base y cerámica de Zirconia de alta resistencia comúnmente utilizada en tratamientos de prostodoncia. Materiales and Métodos: En este estudio experimentalin vitro, se fabricaron 10 muestras en forma de barra de 18 × 5 × 2mm de cada polímero PEEK, aleación de metal base de níquel-cromo y cerámica de circonio. La mitad de las muestras en cada grupo fueron sometidas a 5000 ciclos térmicos entre 5°C - 55°C con 20 segundos de tiempo de permanencia y 20 segundos de tiempo de transferencia para simular condiciones orales. Todas las muestras se sometieron a una prueba de flexión de tres puntos. Se aplicó ANOVA bidireccional seguido de la prueba de Tukey para comparar la resistencia a la flexión media de los grupos con y sin termociclado a un nivel de significancia de 0.05. Resultados: La resistencia a la flexión de la aleación de metal base, Zirconia y PEEK fue de 1387,70 ± 45,50 MPa; 895,13 ± 13,99 MPa y 192.10 ± 5,37 MPa, respectivamente. La diferencia fue significativa entre los grupos (p<0,001). El termociclado no tuvo un efecto significativo sobre la resistencia a la flexión de las muestras en ningún grupo (p=0,306).Conclusión:El polímero de alto rendimiento PEEK tiene una resistencia a la flexión más baja que la aleación de metal base y la cerámica de circonio, y su resistencia a la flexión no se vio afectada por el termociclado. PEEK parece ser capaz de resistir las fuerzas masticatorias en la cavidad oral, con la necesidad de más estudios in vitroy clínicos.

Computer Aided Designing-Computer Aided Milling in Prosthodontics: A Promising Technology for Future.

Computer aided designing-computer aided milling (CAD-CAM) technology was introduced to dentistry way back in 1971. Over the years there has been a constant upgradation in the quality and popularity of its application to dentistry. CAD-CAM fabricated prosthesis though initially were considered costly and technique sensitive, nowadays they are being extensively used because of advancements in various CAD-CAM systems that have gained popularity. Th e ease of work and reduced chair side time makes them a boon while providing prosthodontics treatment. Dental CAD-CAM systems are being used not only for crowns and bridges, inlays and onlays but also for fabrication of removable prosthesis, stents, and implant components. Th is article reviews the evolution of the CAD-CAM system and its applications in the fi eld of dentistry over the past two and a half decades.

Scope of prosthodontic services for patients with head and neck cancer.

Patients with head and neck cancer face high morbidity due to the disease and its treatment and are affected on a variety of personal and physical levels. Maxillofacial prosthetics offer support for other disciplines in a multidisciplinary setting; can help to prevent / minimize the sequelae from disease and treatment, and offers the patient help in the rehabilitation process. Maxillofacial prosthodontics focuses on optimizing the disrupted rudimentary function of individuals whose rehabilitation will be a lifelong proposition. Normal function may not be achieved but optimal function should always be achieved and the patients can lead a near to normal life.

Comparison of obturator design for acquired maxillary defect in completely edentulous patients.

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.

Evaluation of dimensional accuracy of master models as a function of different thickness of wash impression material [rapid] in two step technique

Impression making is one of the most important steps in fixed prosthodontics. Due to contra-dictory opinions on the issue of the accuracy of silicone impression material as a function of technique, this study was carried out to assess the dimensional accuracy of master casts made by Rapid silicone material as a function of three impression techniques: with 2mm space, with 1mm space and without space for wash thickness. This experimental study was carried out by using laboratory models. Two dies [with and without undercut] served as laboratory models. 10 impressions were taken for each technique and stone models were poured. Six dimensions of 30 models [height and diameter for each die and distance between dies] were measured by digital caliper. The mean differences in measurements in stone model was compared with laboratory model. T-test and ANOVA analysis was used on statistical analysis. Impression techniques with different amount of thicknesses of wash impression material had statistical significant effect on dimensional accuracy of master models. Impression technique with 2mm of space for wash material compared to impression technique with 1mm space and without space for wash material was more preferable

Prosthodontic rehabilitation of hemi-mandibulectomy patients: a case report

A step by step procedure for the construction of an appliance for a patient with a prosthetically reconstructed mandible has been described. Various other treatment modalities available for such patients have been discussed. In conclusion, a very complicated problem has been approached through a very simple treatment regimen, which is frequently regarded as a preferred mode of treatment