1.The effects of spure and invents on the casting accuracy and porosity of ti-ni castings.
Lee Ra CHO ; Yang Jin YI ; Chan Jin PARK
The Journal of Korean Academy of Prosthodontics 2003;41(3):342-350
STATEMENT OF PROBLEM: Titanium-Nickel alloy might be used in various prosthetic restorations since it has a unique property such as super-elasticity and high fatigue resistance. However, little is known about the casting ability of this alloy. PURPOSE: This in vitro study compared the casting accuracy and the porosity made with different investments and various sprue designs to ascertain what casting condition would be better for the fabrication of Ti-Ni cast restorations. MATERIAL AND METHODS: A total of 70 Ti-Ni alloy crowns were made and divided into 7 groups of 10 copings on a metal master die. For measuring the effect of the sprue numbers, two groups with one and two 8-gauge sprues were compared. Moreover, the results of the conventional sprue and the double thickness sprues were compared. Three investments were used; carbon free phosphate bonded investment, titanium investment and gypsum bonded investment. The cast restorations were evaluated at 48 points on the entire circumferential margin with a stereomicroscope measuring in micrometers. Each crown was radiographically examined for casting defects and porosity. Data on casting accuracy were analyzed using two-way and Post hoc Scheffe's comparison to determine whether significant differences existed at the 95% confidence level. Student-Newman-Keuls test were performed to identify significant differences in the number of voids. RESULTS: The double sprueing group and double thickness group had significantly less marginal discrepancy than the single sprueing group (P<.05 and P<.01, respectively). The castings with phosphate bonded investment showed the least marginal discrepancy and the smoothest surface. The castings invested in the gypsum bonded investment had the greatest gaps in margin and the largest failure rate. The double sprueing group and phosphate bonded investment group had significantly smaller void numbers and smaller void size than the other groups. CONCLUSION: Within the limitations of this in vitro study, the casting accuracy of the groups using thicker, double sprue design and the phosphate bonded investment was significantly superior. Moreover, void number and size were less than other groups.
Alloys
;
Calcium Sulfate
;
Carbon
;
Celiac Disease
;
Crowns
;
Fatigue
;
Investments
;
Porosity*
;
Titanium
2.Three Cases of Hydrocephalus Treated with Acetazolamide.
Dong Hyun CHO ; Hyun Mi LEE ; Chang Soo RA
Journal of the Korean Society of Neonatology 1997;4(2):280-287
Hydrocephalus is a common malformation of the central nervous system and its cause may be either congenital or acquired. The imbalance between CSF formation and absorption, obstruction of CSF pathways, impaired venous absorption, and over secretion of CSF results in excessive accumulation of the fluid in the ventricles, leading to hydrocephalus. Although ventriculo-peritoneal shunt is regarded as the main and definitive therapy for rapidly progressive hydrocephalus, shunts in newborns have a high failure rate and thus there have been a search for alternative non-invasive techniques. Acetazolamide is a carbonic anhy- drase inhibitor, which acts by reducing production of CSF in the choroid plexus. Admini- stration of acetazolamide will decrease the rate of CSF production, preventing progressive ventricular enlargement. We experienced three cases of neonatal hydrocephalus successfully treated by long-term administration of acetazolamide. Brief review and related literatures were also presented.
Absorption
;
Acetazolamide*
;
Carbon
;
Central Nervous System
;
Choroid Plexus
;
Humans
;
Hydrocephalus*
;
Infant, Newborn
;
Ventriculoperitoneal Shunt
3.A STUDY ON THE DIMENSIONAL ACCURACY OF MODELS USING 3-DIMENSIONAL COMPUTER TOMOGRAPHY AND 2 RAPID PROTOTYPING METHODS.
Lee Ra CHO ; Chan Jin PARK ; In Woo PARK
The Journal of Korean Academy of Prosthodontics 2001;39(6):633-640
Statement of problem. Relatively low success rate of root analogue implant system was supposed to be due to the time duration between extraction and implant installation. The use of three-dimensional computer tomography and the reconstruction of objects using rapid prototyping methods would be helpful to shorten this time. Purpose. This aim of this study was to evaluate the application possibility of the 3-dimensional computer tomography and the rapid prototyping to root analogue implants. Material and methods. Ten single rooted teeth were prepared. Width and height of the teeth were measured by the marking points. This was followed by CT scanning, data conversion and rapid prototyping model fabrication. 2 methods were used; fused deposition modelling and stereolithography. Same width and height of this models were measured and compared to the original tooth. Results. Fused deposition modeling showed an enlarged width and reduced height. The stereolithography showed more exact data compared with the fused deposition modelling. Smaller standard deviation were recorded in the stereolithographic method. Overall width error from tooth to rapid prototyping was 7.15% in fused depostion modelling and 0.2% in stereolithography. Overall height showed the tendency of reducing dimensions. Conclusion. From the results of this study, stereolithography seems to be very predictable method of fabricating root analogue implant.
Tomography, X-Ray Computed
;
Tooth
4.The effect of tooth brushing and thermal cycling on a luster change of ceromers finished with different methods.
The Journal of Korean Academy of Prosthodontics 2000;38(3):336-347
STATEMENT of PROBLEM: Luster loss in esthetic anterior ceromer restoration can occur and can be related with rough surface texture. Understanding durability of surface finishing methods like polishing and surface coating have critical importance. PURPOSE: This study evaluated the effect of tooth brushing and thermal cycling on surface luster of 3 ceromer systems (Artglass, Targis, Sculpture) treated with different surface finishing methods. MATERIAL AND METHODS: Seventy-two samples were prepared: 12 for control group Z100, 12 for Artglass, 24 for Targis, and 24 for Sculpture. Half of the Targis and Sculpture were polished according to the manufacturer's recommendation. The rest of the samples were coated with staining and glazing solution for Targis and Sculpture, respectively. All specimens were subjected to 10,000 cycles between 5 degreesC and 55 degreesC with 30 seconds dwell time. Tooth brushing abrasion tests were performed in a customized tooth brushing machine with 500g backand forth for 20,000 cycle. Luster comparisons were based on grading after direct observation, and light reflection area was measured with Image analysis software. RESULTS: All materials showed an decrease in luster grade after thermal cycling and tooth brushing. The post-tooth brushing results revealed that the glazed Sculpture had greater mean luster grade than did any other groups. While, the stained Targis group showed greatest changes after tooth brushing (p>0.05), polished Targis and Sculpture did not show significant changes. However, glazed Sculpture showed discretely fallen out glaze resin. CONCLUSION: From the results of this study, all of the ceromer specimens were much glossy than control composite group after tooth brushing. coatings used for Targis and Sculpture had not durability for long term use.
Sculpture
;
Tooth*
5.Age-Differences in Depressive Symptoms and Screening in Late Life.
Journal of Korean Geriatric Psychiatry 2013;17(1):3-7
Depression is a common psychiatric disorder, but accurate recognition of depression is somewhat difficult because of different symptom presentation by age. The consequence of not recognizing to depression is that clinically significant and potentially treatable depression might be overlooked, misdiagnosed, and mistreated in depressive patients. The overlap of somatic symptoms of depression and physical illness and minimal expression of sadness is common in old age. Because of that reasons, alternative approach to identifying depression should be provided by proper screening instruments.
Depression
;
Humans
;
Mass Screening
6.A Study of Umbilical venous Blood of pH, pCO2, Bicarvonate and Base Excess in Normal Term Infat and High Risk Infant.
Journal of the Korean Pediatric Society 1980;23(5):366-375
The levels of pH,pCO,bicarbonate, and base excess in umbillical venous blood were measured at birth of life in 30 normal term infant and 27 high risk infants. The study group was divided into two categories by clinical evaluation: first group of normal term infant without high risk indication and second group of high risk infants. Following results were obiained. 1) The average level of umbilical venous blood pH in normal group was 7.3260.001 and high risk group was 7.3180.002(7.326 versus 7.318,respecitvely,p>0.05) 2) The average Apgar Score in normal group was 9.30.95 and more acidotic high risk group was 7.42.54 3) The average level of pCO in normal group was 43.361.36mmHg and high risk group was 43.952.36mmHg(43.36 respecitively, p>0.05) 4) The average level of pCo in normal group was 21.550.85mmEq/L and high risk group was 20.030.78mEq/L(21.55 versus 20.03mEq/L respectively,p>0.05) 5) The average level of base excess in normal group was -2.610.76mEq/L and high risk group was -3.060.91mEq/L(-2.61 versus -3.06mEq/L respecitively,p?0.05) 6) Relationship between hP and Apgar Score in normal group was False normal (6.7%),False abnormal(10%) and high risk group was False normal (14.8%) False abonromal(7.4%).
Apgar Score
;
Humans
;
Hydrogen-Ion Concentration*
;
Infant*
;
Parturition
7.Full mouth fixed implant rehabilitation in a patient with generalized aggressive periodontitis.
Yoon Hyuk HUH ; Hyung Joo SHIN ; Dae Gon KIM ; Chan Jin PARK ; Lee Ra CHO
The Journal of Advanced Prosthodontics 2010;2(4):154-159
BACKGROUND: Generalized aggressive periodontitis (GAP) is a destructive periodontal disease that can develop in young age. Only a few cases of full mouth rehabilitation, using dental implants, have been reported in a patient with aggressive periodontitis. CASE DESCRIPTION: This clinical report describes the treatment procedures and results of full mouth rehabilitation in a patient with aggressive periodontitis. After all teeth were extracted, 6 implants were placed in the maxilla and mandible, respectively. Fixed detachable implant prostheses were made. The patient was satisfied with the final results. She was followed for 10 months postloading. CLINICAL IMPLICATION: For a long-term success, continuous maintenance care is critical, as the contributing factors of the disease (such as immune factors or periodontal pathogens) may not be controlled adequately.
Aggressive Periodontitis
;
Dental Implants
;
Humans
;
Immunologic Factors
;
Mandible
;
Maxilla
;
Mouth
;
Mouth Rehabilitation
;
Periodontal Diseases
;
Prostheses and Implants
;
Tooth
8.Marginal accuracy and fracture strength of Targis/Vectris Crowns prepared with different preparation designs.
The Journal of Korean Academy of Prosthodontics 2000;38(6):791-799
STATEMENT OF PROBLEM: Targis/Vectris restorations provide excellent esthetics. Marginal accuracy is significantly influenced by the preparation design. There were no studies to examine the effect of preparation design on the marginal discrepancy and fracture strength of Targis/Vectris crowns. PURPOSE: This study evaluated the marginal accuracy before and after cementation, and the fracture strength of FRC/Ceromer(Targis/Vectris) crowns according to different preparation design. MATERIAL AND METHOD: Three metal dies with different convergence angles(6degrees, 10degrees, 15degrees) were prepared. Total 30 (10 for each angle) Targis/Vectris crowns were made. The restorations were evaluated for adaptation of the margin before and after cementation, then were compressively loaded to failure. Fracture surfaces of the crowns were examined using a SEM. Results. The mean marginal gap was 49micrometer for 6degrees, 55micrometer for 10degreesand 70micrometer for 15degreesand in clinically acceptable level. The mean marginal gap increased significantly after cementation. The increasing amount during cementation was the largest in the 6degrees group. The crowns on 6o convergence angle had a significantly higher fracture strength than the crowns on 15degrees angle. Mean fracture strength of total crowns regardless of convergence angle was 1390 N, which was higher than all-ceramic crowns. SEM observation showed two-mode fracture pattern. CONCLUSION: From the results of this study, all of the FRC/Ceromer crowns had clinically acceptable marginal accuracy and could withstand the bite force. Moreover, less convergent angle than all-ceramic crown might be recommended for preparation procedure.
Bite Force
;
Cementation
;
Crowns*
;
Esthetics
9.A Review of the Endoscopic Extraction in 52 Cases of the Upper Gastrointestinal Foreign Bodies.
Moon Sung LEE ; Dong Jip RA ; Jin Hong KIM ; Sung Won CHO ; Chan Sup SHIM
Korean Journal of Gastrointestinal Endoscopy 1990;10(1):47-52
A clinical review was performed in 52 cases with the foreign body in the gastrointestinal tract who underwent the endoscopic extraction of fereign body at our hospital from June 1985 to October 1989. The results are as following. 1) The most prevalent age was under 10 years of age (21 cases, 40.4%), and male was more prevalent than female (M:F=1.6:1). 2) The most common site of foreign bodies was esophagus (35 cases, 67.3%), next stomach (15 cases, 28.9%). 3) The foreign bodies in esophagus were coins (18 cases, 51.4%), meats (7 cases, 20.0%), bones (5 cases, 14.3%), other food materials or metals (5 cases, 14.3%)in order of frequency, and those in the stomach wer bezoars (7 cases, 50.0%), coins (2 cases, 14.3%), suture materials (2 cases, 14.3%), others (baduk stone, pin, tack, cross). 4) The combined diseases with upper gastrointestinal foreign bodies were the passage disturbances (11 cases, 21.2%) due to stenosis, and schizophrenia (1 case), aleoholism (1 case). 5) Complications by foreign bodies were 8 cases (15.4%), such as eisophageal laceration or ulceration (4 cases), esophaigeal perforation (1 case), aspiration pneumonia(1 case), duodenal obstruction (2 cases). 6) Successful rate of the endoscopic extraction was 88.5%(46 in 52 cases). And 6 unsuccessful cases were 4 cases who have gastric bezoars too hard and large to extract, a case with esophageal perforation, and a case with bezoar in the third portion of duodenum.
Bezoars
;
Constriction, Pathologic
;
Duodenal Obstruction
;
Duodenum
;
Esophageal Perforation
;
Esophagus
;
Female
;
Foreign Bodies*
;
Gastrointestinal Tract
;
Humans
;
Lacerations
;
Male
;
Meat
;
Metals
;
Numismatics
;
Schizophrenia
;
Stomach
;
Sutures
;
Ulcer
10.A case of allopurinol-induced eosinophilia.
Bo Ra SON ; Chang Kyeu LEE ; Yun Jung CHO ; In Sun KIM ; Min Ja KIM
Korean Journal of Hematology 1991;26(1):189-193
No abstract available.
Eosinophilia*