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Biomedical subjects

G C Cho

Publications and source records attributed to G C Cho.

25 records · Page 2Linked to original sources

Tensile bond strength of polyvinyl siloxane impressions bonded to a custom tray as a function of drying time: Part I.

Time-dependent bond strength studies of two polyvinyl siloxane impression materials to acrylic resin disks with their respective adhesives were studied to determine the optimal time for maximum bond strength. Six groups were tested with varying adhesive dry times of 0, 7, 15, and 60 minutes and 8 and 24 hours before testing. The results indicated that the bond strength of the adhesive increased at least twofold from time zero to 7 minutes adhesive dry time and peaked at 60 minutes for one of the materials and at 8 hours for the other. Bond strengths increased rapidly to the 15-minute test interval and then seemed to plateau. Both materials exhibited decreased adhesive bond strengths at 24 hours.

Acrylic Resins↗

Efficient soldering index materials for fixed partial dentures and implant substructures.

Multiple-unit fixed partial dentures routinely require an intraoral index to ensure accurate fit. One of the most commonly used materials is Duralay acrylic resin, which has yielded satisfactory clinical results, but one disadvantage has been a prolonged setting time. This study compared the setting times of two autopolymerizing resins, Duralay and G. C. Pattern resin. The dimensional accuracy of these materials was also compared with one light-cured resin, G.C. Unifast light-cure resin. All three materials were suitable to relate castings with clinically acceptable outcomes, and chairside time could be saved with the use of recently introduced indexing materials.

Dental Abutments↗

Custom characterization of the provisional restoration.

The fabrication of esthetic custom provisional restorations that provide optimum esthetics and function accomplished with minimal chairside time is described. The effects of mamelons, translucency, and incisal haloes are reproduced to mimic natural dentition. The technique is based on a provisional shell that is made in the laboratory and relined intraorally for a more precise fit. In addition, it can be characterized chairside to better satisfy the esthetic demands of the patient. The laboratory-processed shell allows us to attain optimal physical characteristics with auto-polymerizing methylmethacrylate resin.

Denture Design↗

Progress in treatment of thoracoabdominal and abdominal aortic aneurysms involving celiac, superior mesenteric, and renal arteries.

This is a report of surgical treatment of thoracoabdominal aortic aneurysms and aneurysms of the abdominal aorta from which the visceral vessels arise during the 18 year period from April 5, 1960, to April 20, 1978. The extent of aneurysm is divided into five groups. Group I (10 patients) involved most of the thoracic and abdominal aorta down to celiac axis. Group II (22 patients) involved most of the thoracic and abdominal aorta distal to left subclavian artery. Group III (20 patients) were those with lesser involvement of the thoracic aorta and most of the abdominal aorta. Group IV (18 patients) with involvement of the entire abdominal aorta and Group V (12 patients) with involvement of lower abdominal aorta and renal arteries. Treatment in the majority of these cases was by graft inclusion technique with visceral vessel reattachment by direct suture of orifice to openings made in the graft. Intercostal and/or lumbar arteries were also reattached in some with the more extensive lesions. Aortic and renal artery occlusion times varied from 15 to 155 minutes. Paraplegia developed in five patients with the more extensive lesions but was reduced to one-third and made less severe by reattaching intercostal and lumbar arteries. Renal dysfunction was mild in four patients and severe in three patients after operation. All these were transient except one who died while recovering from renal failure. The latter cases were those difficult to reattach or were not initially successful and required reoperation. Of the 82 patients, 77 (94%) survived operation and long-term followup was obtained in 95% of cases, 23 performed over five years ago. Actuarial curves were constructed and compared to survival curves following simple infrarenal abdominal aortic resection. The survival rate both immediately and at six years, were the same.

Adult↗