Orthodontic bracket bonding to glazed full-contour zirconia

OBJECTIVES: This study evaluated the effects of different surface conditioning methods on the bond strength of orthodontic brackets to glazed full-zirconia surfaces. MATERIALS AND METHODS: Glazed zirconia (except for the control, Zirkonzahn Prettau) disc surfaces were pre-treated: PO (control), polishing; BR, bur roughening; PP, cleaning with a prophy cup and pumice; HF, hydrofluoric acid etching; AA, air abrasion with aluminum oxide; CJ, CoJet-Sand. The surfaces were examined using profilometry, scanning electron microscopy, and electron dispersive spectroscopy. A zirconia primer (Z-Prime Plus, Z) or a silane primer (Monobond-S, S) was then applied to the surfaces, yielding 7 groups (PO-Z, BR-Z, PP-S, HF-S, AA-S, AA-Z, and CJ-S). Metal bracket-bonded specimens were stored in water for 24 hr at 37℃, and thermocycled for 1,000 cycles. Their bond strengths were measured using the wire loop method (n = 10). RESULTS: Except for BR, the surface pre-treatments failed to expose the zirconia substructure. A significant difference in bond strengths was found between AA-Z (4.60 ± 1.08 MPa) and all other groups (13.38 ± 2.57 - 15.78 ± 2.39 MPa, p < 0.05). For AA-Z, most of the adhesive remained on the bracket. CONCLUSIONS: For bracket bonding to glazed zirconia, a simple application of silane to the cleaned surface is recommended. A zirconia primer should be used only when the zirconia substructure is definitely exposed.

A Case of an Adrenocortical Carcinoma with Pulmonary Embolism as the Initial Manifestation

The annual incidence of a first episode of deep vein thrombosis or pulmonary embolism (PE) in the general population is 120 per 100,000. Cancer is associated with an approximately 4- to 7-fold higher risk of thrombosis. Adrenocortical carcinoma (ACC) is a rare type of malignancy, accounting for 0.02% of all cancers reported annually. Approximately 40% of ACCs are nonsecretory. Most patients with nonsecreting tumors have clinical manifestations related to tumor growth (e.g., abdominal or flank pain). Often the adrenal mass is detected by chance via radiographic imaging. As a result, most ACC patients are diagnosed at an advanced stage and have a poor prognosis. Herein, we report a case of a 54-year-old woman who was admitted to our emergency department complaining of dyspnea. She was diagnosed with ACC accompanied by thrombi in the pulmonary artery and inferior vena cava. We performed a left adrenalectomy and administered adjuvant radiotherapy. The patient is currently receiving warfarin and adjuvant mitotane therapy. She was incidentally diagnosed with ACC, with PE as the initial manifestation.

Prevalence Rate and Risk Factors of Dementia Compared between Urban and Rural Communities of the Metropolitan Kwangju Area / 신경정신의학

OBJECTIVES: The purpose of this study was to investigate the prevalence rate and risk factors of dementia in an urban and a rural sample of older persons in the metropolitan Kwangju area, Republic of Korea. In addition, the prevalence rate and risk factors of dementia between the two samples were compared. METHODS: A two-phase epidemiological study of residents aged 65 or over(N=1,598) was conducted in a highly developed, urban and a non-contiguous, poorly developed, rural area of metropolitan Kwangju. In the first(screening) phase, 38 trained research assistants collectively performed in-home interviews for all participants. Detailed sociodemographic characteristics were gathered and the Korean version of Mini-Mental State Examination(MMSE-K) was administered. In the second(diagnosing) phase, diagnosis of dementia was established for those scoring 24 or less on the MMSE-K in the screening phase(N=431), and etiological types of dementia were classified to Alzheimer's disease (AD), vascular dementia(VaD) or miscellanous type by two teams of experts. Prevalence rate of dementia was determined in the participants, and age-standardized prevalence rate adjusted by age distribution in metropolitan Kwangju was estimated. For AD, the risk factors were investigated in all participants, and analyses were repeated for the urban and rural samples separately. RESULTS: The participating rates in the first and second phases were 71.0%(N=1,134) and 83.2% (N=410), respectively. In the participants, the prevalence rates of dementia(all types), AD and VaD were 9.7%, 5.2% and 1.8%, respectively. The age-standardized prevalence rates were 10.7%, 5.7% and 1.9%, respectively. Aging, female gender and no education(complete lack of formal education) were identified as independent risk factors for AD. No difference between the urban and rural samples was observed in the prevalence rates of dementia(all types), AD and VaD. However, risk factors for AD differed between these areas. In the urban sample, no education was the only significant factor; whereas, aging and female gender were identified as risk factors in the rural sample. CONCLUSION: A high prevalence rate of dementia was observed among old persons in metropolitan Kwangju, consistent with previous studies conducted in other Korean areas. The risk factor profiles for AD differed between urban and rural settings. The results of this study reflect the current status of dementia in Korea and suggests that appropriate management and prevention strategies for dementia should be tailored toward the geographic settings.