Influence of surface treatments and repair materials on the shear bond strength of CAD/CAM provisional restorations

PURPOSE: To evaluate the effect of surface treatments and repair materials on the shear bond strength and to measure the fracture toughness of CAD/CAM provisional restoration materials. MATERIALS AND METHODS: Four CAD/CAM (3D printing: Nextdent C&B and ZMD-1000B Temporary, CAD/CAM resin block: Yamahachi PMMA disk and Huge PMMA block) and four conventional (monometacrylate: Jet and Alike, dimetacrylate: Luxatemp and Protemp 4) materials were selected to fabricate disk-shaped specimens and divided into six groups according to surface treatment (n=10). CAD/CAM materials were repaired with Jet or Luxatemp, while conventional materials were repaired with their own materials. The shear bond strength was measured by using universal testing machine. Ten rectangular column-shaped specimens for each material were fabricated to measure the fracture toughness by single edge v notched beam technique. Statistical analysis was performed by one-way ANOVA. RESULTS: The highest shear bond strength of CAD/CAM materials was achieved by SiC paper + sandblasting. It was also accomplished when repairing 3D printing materials with Luxatemp, and repairing CAD/CAM resin blocks with Jet. Yamahachi PMMA disk showed the highest fracture toughness. Nextdent C&B showed the lowest fracture toughness value but no statistically significant difference from Alike and Luxatemp (P>.05). CONCLUSION: In order to successfully repair the CAD/CAM provisional restoration, mechanical surface treatment and appropriate repair material according to the CAD/CAM material type should be selected. The CAD/CAM provisional materials have proper mechanical properties for clinical use as compared to conventional materials.

Full mouth rehabilitation of edentulous patient with intellectual disability using implants and monolithic zirconia / 대한치과보철학회지

People with class I intellectual disability need lifelong assistance and protection from their surroundings due to impaired adaptive functioning. They have poor oral health and show higher prevalence of dental caries, periapical inflammation and tooth loss that require proper prosthetic restoration. Because removable prostheses for intellectually disabled patients often lack stability, retention, and maintenance, fixed prostheses are essential and the only available option is dental implants. In this case, a 45 year-old male patient with class I intellectual disability had poor oral hygiene with most of his teeth missing and visited the clinic to recover his masticatory function. Due to such systemic conditions, the definitive restoration of choice was the implant-supported fixed dental prosthesis made of biocompatible and highly strong monolithic zirconia. In consequence of the treatment process, the patient was able to improve his oral environment aesthetically and functionally.

Effects of Chromium Exposure on the Level of Urinary 8-Hydroxydeoxyguanosine / 대한산업의학회지

OBJECTIVES: To investigate the possibility of utilizing DNA adduct as a carcinogenic biological marker for workers exposed to chromium, and the effect of chromium exposure on the formation of urinary 8-hydroxydeoxyguanosine(8-OH-dG) was also evaluated. METHODS: The chromium concentrations of venous blood and urine were measured in 20 chromium exposed workers(exposure group) and in 11 chromium workers(control group) who were not exposed. The concentration of 8-OH-dG in their urine was determined using high performance liquid chromatography with electrochemical detection. RESULTS: The blood chromium concentration was significantly higher in the exposure group ( 0.46+/-0.18 microgram/100 ml) than in control group(0.27+/-0.15 microgram/100 ml), but the urinary chromium concentration was not significantly higher in the exposure group. The urinary 8-OH-dG was higher in the exposure group(1.71+/-1.82 micromol/mol creatinine) than that in the control group(0.45+/-0.46 micromol/mol creatinine) and was significantly correlated with the blood chromium concentration(r=0.49). Results of multiple regression analysis revealed that the level of urinary 8-OH-dG depended upon the level of the blood chromium conc entration ( r2= 0.21). CONCLUSIONS: Urinary 8-OH-dG was significantly related to chromium exposure and this finding suggests the possibility that urinary 8-OH-dG could be used as a biological index of chromium induced DNA damage.

Factors Influencing the Intention of Admission into a Charged Nursing Home for the Elderly / 예방의학회지

OBJECTIVES: To gather information about the factors which influence the interest and intention of admission into charging nursing homes for the elderly(CNH), as these homes represent an important method for resolving the problems related to the rapid population aging occurring in Korea. METHODS: A face-to-face interview survey was carried out with 328(men 159, women 169) patients over 60 years old who were admitted at 2 university hospitals and 5 general hospitals in the Busan area between December 1998 and March 1999. Data were analyzed through t-test, ANOVA, correlation and multiple regression analysis. microgram/g RESULTS: The mean age and years of education of the study population was 67.8 and 7.7 years, and the types of chronic degenerative disease included musculoskeletal disorders(20.1%), cerebrovascular disease(17.1%), and diabetes(14.3%). The major forms of household living arrangement prior to admission were elderly alone(22.6%), and elderly couple(33.5%), while about half of them(55.5%) didn't want to live with their children in the future. Almost half were paying medication fees by themselves(46.6%). The level of actual intention of admission(3.07+/-1.39) into a CNH was lower than that of interest(3.22+/-1.33)(p<0.01). Multiple analysis revealed that the intention of admission increased with decreasing number of future supportive persons(beta=0.107), lower level of activity in daily life(beta=0.447), and longer years of education(beta=0.447) with 32.7% of R2. As for the factors which determined the admission into a CNH, the fee and facilities were considered to be most important, and professional nursing and physician's care were the most desired services. In nomenclature, they preferred "elderly hospital" or "elderly health center" to CNH. CONCLUSIONS: Interest in CNH is increasing recently, but existing studies about patient experiences in CHN are still limited. This study may form a basis for future examinations of the needs and uses for CNH. Active financial support and public information are considered by the authors to be important factors for the induction of welfare services for the elderly, through CNH.

Meta Analysis of Symptom Improvement through Eradication of Helicobacter pylori in Patients with Non-ulcer Dyspepsia / 예방의학회지

OBJECTIVES: This study was conducted to determine, by reviewing the literature, whether treatment of Helicobacter pylori infection in patients with non-ulcer dyspepsia affects symptoms. METHODS: We retrieved the literature using MEDLINE search, with nonulcer dyspepsia and Hericobacter pylori and treatment as key words, which were reported from 1984 to 1998, and manual literature search. The criteria for inclusion was as follows; 1) The paper should have confirmed nonulcer dyspepsia as case definition. 2) The paper should have performed a randomized, blind trial. 3) Confirmation of Helicobacter pylori eradication should be done 4 weeks after treatment. 4) studies with no information on measurement of symptoms after treatment were not accepted. The percentage of patients with symptom improvement after eradication therapy for Helicobacter pylori infection was calculated. Cumulative odds ratio was compared by fixed effect model and random effect model as sensitivity and funnel plot was used to evaluate publication bias. RESULTS: The overall effect size of symptom improvement was calculated by cumulative odds ratio. Cumulative odds ratio of random effect model was 4.16(95% CI: 1.55-11.19). Before integrating each effect sizes into common effect size, the homogeneity test was conducted and random effect model was selected(Cochran's Q=41.08 (d.f=10, p<0.001)). The heterogeneity across studies was evaluated and the different methodological aspects of studies led to differences between study results. CONCLUSIONS: The results suggest that the eradication of Helicobacter pylori in patients with non-ulcer dyspepsia results more symptom improvement. In studies that shows the opposite results there are methodological aspects explaining the heterogeneity.