2.The effects of mechanical and thermal fatigue on the shear bond strength of orthodontic adhesives.
Wan Cheal SHIN ; Jong Sung KIM ; Jong Ghee KIM
Korean Journal of Orthodontics 1996;26(2):175-186
The purpose of this study was to examine the effects of mechanical and thermal fatigue on the shear bond strength(SBS) of stainless steel mesh brackets bonded to human premolar teeth with 3 no-mix adhesives. The stainless steel mesh bracket was Ormesh(Ormco, .022 slot) and three types of no-mix adhesives were Ortho-one(Bisco), Monolok2(RMO), System 1+(Ormco). The 10(6) loadcycles of 17.4x10(2)sin2piftlg . cm and the 1,000 thermocycles of 15 second dwell time in each bath of 5degrees C and 55degrees C were acturated as mechanical and thermal fatigue stress, and SBS were measured after each fatigue test. The fracture sites were analyzed by stereoscope and scanning electron microscope. The results obtained were summarized as follows; 1. Before thermocycles, Monolok2 showed the highest Knoop hardness number(KHN, 64.03kg/mm2) and System 1+ showed the lowest value(31.60kg/mm2). After thermocycling, Monolok2 also showed the highest KHN(38.03kg/mm2) and system 1+ showed the minimum(20.87kg/mm2). The KHN of Ortho-one, Monolok2, System 1+ significantly decreased after thermocycling(P<0.01).
Adhesives
;
Baths
;
Bicuspid
;
Dental Cements*
;
Fatigue*
;
Hardness
;
Humans
;
Stainless Steel
;
Tooth
3.A case of metastatic malignant pheochromocytoma response to high dose 131I-MIBG treatment after surgery.
Shin Won LEE ; Jung Guk KIM ; Sung Woo HA ; Byeong Cheal AHN ; Jae Tae LEE ; Bup Wan KIM ; Bo Wan KIM
Korean Journal of Medicine 2004;67(Suppl 3):S871-S875
Approximately 10% of pheochromocytomas are malignant and its major criteria are tumor invasion of capsular blood vessel as well as metastatic invasion of other tissues. It is general rule that all resectable masses have to be removed surgically. However, there is no definite treatment modality about unresectable masses or microinvasive lesions. We experienced a case of 45 year-old male patient who was referred to our hospital for treatment of hypertension and headache. The plasma and urine catecholamine were increased above normal values and its metabolites also were increased. 131I-metaiodobenzylguanidine (MIBG) scan showed right adrenal mass and metastatic lesion of left iliac bone. This lesion was consistent with findings of the abdomen computed tomography (CT) and electron beam tomography (EBT) scan. We diagnosed this case as malignant pheochromocytoma. We removed primary tumor mass by wide excision and treated this patient with high dose 131I-MIBG. We report this case who shows good response to the high dose 131I-MIBG after surgery.
3-Iodobenzylguanidine
;
Abdomen
;
Blood Vessels
;
Headache
;
Humans
;
Hypertension
;
Male
;
Middle Aged
;
Neoplasm Metastasis
;
Pheochromocytoma*
;
Plasma
;
Reference Values
;
Tomography, X-Ray Computed