No abstract available.
Methylmethacrylate*

No abstract available.
Methylmethacrylate*

No abstract available.
Methylmethacrylate*

No abstract available.
Methylmethacrylate*

No abstract available.
Methylmethacrylate* ; Plagiocephaly*

No abstract available.
Forehead* ; Methylmethacrylate*

PURPOSE: The porosity of the bone cement is the most important cause of fatigue failure, the most common mode of failure of bone cement using widely in arthroplasty. It is important to evaluate the porosity of bone cement for improvement or development of bone cement, but the conventional 'stain, 'cut, and 'polish, manual method takes long time and efforts. So it is necessary to develop a new technique for evaluation of porosity of bone cement. We tried a technique using computer image analysis system to evaluate the porosity of bone cement specimen and assess efficacy of the method. Simultaneously we evaluated the relationship between the porosity of bone cement and fatigue failure. MATERIAL AND METHODS: We made 59, 2.5inch-length bone cement specimens(30 Simplex P, 29 Palacos R) using Simplex P and Palaces R which are widely using in clinical situation and checked radiogram using mammography film. After scanning the mammography film, we measured the porosity of the bone cement specimens using NIH(National Institute for Health) Image 1.6 version image analysis program. We also, measured the porosity of the bone cement specimens with conventional 'stain','cut' and 'polish' method, after then compared the results of two methods. Simultaneously, we evaluated the relationship between porosity & fatigue failure by loading 9.0, 10.0, 12.5 and 15.0 MPa load with frequency of 10Hz to the bone cement specimens under the physiologic condition. RESULTS: The coefficient of relation of simplex P and palaces R was 0.729 and 0.713 respectively, so there was high relationship between the image analysis system method and conventional one. It was easy and took shorter time to measure the porosity of bone cement specimens with image analysis system. There was high correlation between cement porosity and fatigue failure, regardless of level of load. CONCLUSION: It was very easy and fast to measure the porosity of the bone cement specimens with image analysis system and there was high correlation between cement porosity and fatigue failure.
Arthroplasty ; Fatigue ; Mammography ; Methylmethacrylate ; Porosity*

Methylmethacrylate has been proven to be successful in craniofacial alloplastic contouring surgery over several decades. Especially, for the patient with only forehead irregularity after the skull trauma, the alloplastic contouring surgery with methylmethacrylate onlay implant is the choice of treatment. The major advantage of methylmethacrylate is that it is completely malleable in the initial stages of hardening, thus permitting an optimal contouring. However, due to its incapability of direct bonding to the surrounding tissues and consequent lack of fixation, additional fixation technique is necessary. Several different methods have been established to prefabricate methylmethacrylate for cranioplasty, but they are complex; no one-stage procedure. In case of forehead irregularity we performed craniofacial contouring using methylmethacrylate and fixation with internal screw-locking method. Firm fixation, molding in situ, and easiness of manipulation are potential advantages over previously established methods.
Forehead ; Fungi ; Humans ; Inlays ; Methylmethacrylate* ; Skull

The purpose of the present study was to evaluate the effects of several implant surface treatments to the bone formation, by placing Machined implants, 75 micrometer Calcium phosphate-blasted implants and Al2O3- blasted and acid-etched implants in rabbit tibia through histomorphometric study. Two animals of each group were sacrificed at 2, 4, 8 weeks. The specimens containing the implants were dehydrated and embedded into hard methylmethacrylate plastic. Thereafter, the sections were ground to 50 micrometer. The specimens were stained with Villanueva bone stain for a light microscopic study. The results were as follows; 1. When the surface roughness of three different implants was measured by Surfcorder, the Ra of the Machined group, the RBM group and the SLA group was 0.16 micrometer, 0.44 micrometer, and 1.08micro meter. 2. When examining the surfaces of the implants in the scanning microscope, Machined implant has the smooth surface with a few scratches, RBM implant has the rough surface with curled ridges and valleys, and SLA implant has the rough surface structures such as sharp protruding parts and micropits measuring 1-2 micrometer in diameter. 3. After 2 weeks of implantation, the percentage of bone-to-implant contact of the Machined group, the RBM group and the SLA group was 26.86%, 35.40% and 45.99%. However, its differences between each group decreased during the healing periods. 4. After 2 weeks of implantation, the percentage of bone area inside the threads of the Machined group, the RBM group and the SLA group were 21.55%, 30.43% and 41.18%. However, its difference of bone area between machined group and surface treatment groups was maintained but the difference within the surface treatment groups decreased during the healing periods. In summary, the amount of bone formation in RBM and SLA group was greater than Machined group in early healing stage. These results suggest that RBM and SLA implants can reduce the healing period for osseointegration and may be suitable for early function.
Animals ; Calcium ; Dental Implants* ; Methylmethacrylate ; Osseointegration ; Osteogenesis ; Plastics ; Tibia*

The idea of replacement for opaque cornea by using of artificial material such as a transparent glass piece is an old thinking since year of 1777(Pellier de Quengsy). But the active researches on the concept of artificial corneas as an optical property were stimulated since the synthesis of plastic polymers and its application to medical use during the past 30 years. In year of 1964, Dr. Hernando Cardona1) designed his first prototype by using pure methyl methacrylate and/or with autologous unguinal material for an interlamellar supporting plate. By the way, Strampelli (1964) also has designed his osteo-odonto-kerato-prosthesis for same purpose, with another attempt of arthrochondro-keratoplasty in few years later. And Hayano (1969) also has designed a through and through type with methylmethacrylate. Since year of 1980, author has experienced clinically on prostho-keratoplasty by using Cardona's bolt and nut model, which has a flexible perforated retention nut plate in 26 consecutive patients.
Cornea ; Glass ; Humans ; Methylmethacrylate ; Nuts* ; Plastics ; Polymers ; Thinking