Fatma Ünalan

Impact strength of denture polymethyl methacrylate reinforced with different forms of E-glass fibers

Abstract Objective. The purpose of this in vitro study was to determine the reinforcing effect of different forms and concentrations of E-glass fibers on impact strength of denture polymethyl methacrylate. Materials and method. A total of 91 rectangular specimens (84 specimens for test groups and seven for control group) of a heat-cured acrylic resin were fabricated. The test specimens were prepared by modifying the polymethyl methacrylate with the addition of different concentrations (2.5%, 3%, 4%, 5% by volume) of three types (chopped strand mat, woven and continuous unidirectional fibers) of E-glass fibers. The impact strength was evaluated using the Charpy method. Results. While the 5% continuous glass fiber added test group showed the highest mean impact strength, the lowest value belonged to the 2.5% woven glass fiber containing group. When the impact strength values of chopped strand mat and continuous unidirectional glass fiber added groups at all concentrations were compared with the control group, the differences were statistically significant. The impact strength values of the woven glass fiber added groups at all concentrations were higher than that of the control group. However, the difference was non-significant. Conclusion. The impact strength of PMMA was enhanced by including E-glass fibers, increasing parallel with the fiber concentration.

Comparative study of the fatigue strength of five acrylic denture resins

The aim of this in vitro study was to compare the fatigue resistance of three kinds of heat-polymerized acrylic resins (conventional heat-polymerized, rapid heat-polymerized, high impact acrylic resin), a kind of visible light-cured resin and a kind of self-cured acrylic resin. A total of 60 notched and un-notched specimens (65 mm x 10 mm x 3 mm) were fabricated, 12 from each material. The fatigue resistance was measured by applying repeated three-point bending deflection to the specimens. For statistical analysis, Kruskal-Wallis test followed by Dunns multiple comparison tests were used. The Kruskal-Wallis test revealed significant differences in the fatigue resistance among some groups (p<0.05). Conventional- and rapid-heat polymerized resins had lower fatigue resistance values than heat-polymerized high impact acrylic resin, but the differences were statistically non-significant according to Dunns test (p>0.05). High impact acrylic resin was also found to have significantly higher fatigue resistance value than that of self-cured resin and light-cured resin (p<0.05). Further, there was no statistically significant difference between the mean fatigue resistance value of visible light-cured resin and self-cured resin (p>0.05).

Familial gigantiform cementoma with Ehlers - Danlos syndrome: A report of 2 cases

Ehlers-Danlos syndrome is an autosomal dominant hereditary disorder of connective tissue, while familial gigantiform cementoma is a condition that usually manifests as multiple radiopaque cementum-like masses throughout the jaws. This case report discusses the oral management and prosthetic rehabilitation of two patients presenting familial gigantiform cementoma with Ehlers-Danlos Syndrome.

Fatigue resistance of acrylic resin denture base material reinforced with E‐glass fibres

OBJECTIVE The purpose of the study was to determine the effect of different forms and concentrations (2.5, 3, 4, 5% by volume) of glass fibres (chopped strand mat, continuous and woven) on fatigue resistance of acrylic denture base resin. MATERIAL AND METHODS The fatigue resistance was measured by applying repeated three-point bending deflection to the specimens, the cycle frequency of 1.05 g and magnitude of deflection of 2.0 mm. The number of loading cycles needed to cause a fracture in the test specimen was considered the fatigue resistance of the specimen. RESULTS The results of this study revealed that the addition of three different glass fibre forms at all concentrations to acrylic resin did not produce a statistically significant increase in the fatigue resistance (p ≥ 0.05). This study also revealed that there were significant differences (p < 0.05) between glass fibres forms used concerning the effects on the fatigue resistance. CONCLUSION This study showed that the woven glass fibres had a definite superiority over the chopped fibres and the continuous fibres in regard to the fatigue resistance of the acrylic denture base resin.

THE COMPARISON OF THE PRECISION OF DIFFERENT DENTAL RADIOGRAPHIC METHODS IN MANDIBULAR PERI-IMPLANTARY MEASUREMENTS: AN IN VITRO STUDY

Purpose: The objective of this in vitro study was to investigate and compare the precisions of several radiodiagnostic methods used in dentistry for the measurement of peri-implantary sites. Materials and Methods: Six dental implants were placed in a human cadaver mandible. Periapical radiographs obtained with the parallel as well as the bisecting angle technique, digital and conventional panoramic radiographs were used for implant and peri-implant bone measurements. The measurement results at each implant were statistically analyzed. Results: The ICC values for the inter-observer reliability were 0.79 for implant diameters and 0.96 for implant lengths. Statistical significance was not detected between the differences of the measurements of the 2 examiners from the original implant dimensions related to anatomic locations. For both of the examiner measurements, significantly less difference from the original implant dimensions was detected in the parallel technique compared to the other techniques (p<0.05). Conclusion: The present study showed that the most precise peri-implant bone measurements can be obtained from periapical radiographies by using the parallel technique.

Comparative study of impact strength of six acrylic denture resins

Abstract The aim of this in vitro study was to compare the impact strength of three kinds of heat polymerised acrylic resin: a microwave polymerised acrylic resin, a visible light cured resin and a self-cured acrylic resin. From a group of six different materials, a total of 60 specimens (75 × 10 × 3 mm) were fabricated, 10 from each material. The impact strength was evaluated using the Charpy method. The test was performed at room temperature in an impact testing machine (Zwick pendulum impact tester; Zwick GmbH & Co. KG, Ulm, Germany) of a capacity of 0–7·5 J scale; the specimens were fractured. For statistical analysis, Kruskal–Wallis test followed by Dunns multiple comparison test was used. The impact strength values exhibited statistically significant differences among acrylic resin groups (p=0·0001). High impact strength acrylic resin showed the highest mean impact strength value among the materials tested.

DOKU DÜZENLEYİCİLERİN FONKSİYONEL ÖLÇÜ MADDESİ OLARAK KULLANIMI TISSUE CONDITIONERS AS FUNCTIONAL IMPRESSION MATERIALS

OZET Yumusak vc rezilient gecici astar maddeleri olan doku duzenleyiciler; protez kaidesinin altindaki mukozaya gelen stresleri dagitir ve azaltirlar. Sagliksiz doku uzerinde iyilestirici etkiye sahip olmalari sayesinde geri donusebilen hasara sahip dokuyu normal haline dondurebilirler. Fonksiyonel olcu maddeleri, protezin ic yuzeyine veya olcu kasigina uygulandiginda bazal kaidenin sinirlarini, pozisyonunu ve yuzey ozelliklerini fonksiyon halindeyken kaydeden materyallerdir. Ayni sekilde fonksiyonel olcu maddeleri, protezin ic yuzeyinde fonksiyonel stresler altinda olcuyu korumak amaciyla da kullanilirlar. Doku duzenleyicilerin fonksiyonel olcu maddesi olarak kullanilabilecegi ifade edilmektedir. Bu derlemede doku duzenleyici materyallerin, fonksiyonel olcu maddesi olarak kullanildiklarinda ne kadar basarili olduklarindan ve nasil kullanilmalari gerektiginden bahsedilmistir. Anahtar Kelimeler: Doku duzenleyiciler, fonksiyonel olcu. SUMMARY