Biomedical subjects

Wei-hong Zhang

Publications and source records attributed to Wei-hong Zhang.

5 recordsLinked to original sources

PubMed2006

Fracture strength of custom-fabricated Celay all-ceramic post and core restored endodontically treated teeth.

BACKGROUND: The increased use of all-ceramic crown provides a rationale for tooth-colored core. Due to superior mechanical properties, Vita Celay infiltration ceramic developed for crown and bridge works presents the potential for fabricating all-ceramic posts and cores in one piece. This study was conducted to compare the fracture strength of endodontically treated teeth which were thereafter given different types of posts and cores and crowns restoration, respectively. The evaluated post-and-core systems are: custom-fabricated Celay all-ceramic post-core, custom cast metal post-core, and prefabricated stainless steel post (Parapost) with and without 2.0 mm dentine ferrule. METHODS: Sixty freshly extracted human maxillary central incisors were endodontically treated and randomly divided into five groups with 12 samples each. Group A: Celay ceramic post-cores restored teeth with 2.0 mm dentine ferrule. Group B: Celay ceramic post-cores restored teeth with no dentine ferrule. Group C: cast metal post-cores restored teeth with 2.0 mm dentine ferrule. Group D: cast metal post-cores restored teeth with no dentine ferrule. Group E: prefabricated post and composite cores restored teeth with 2.0 mm dentine ferrule. All teeth were restored with Celay ceramic crowns. Each specimen was subjected to a load at a 45-degree angle to the long axis on MTS 810 material testing machine until failure, at crosshead speed of 0.02 cm/minute. Analysis of variance followed by the Newman-Keuls pairwise multiple comparison tests were used to compare the results of the groups tested. RESULTS: There was a statistically significant difference among the five groups (P < 0.01). Celay ceramic post-cores restored teeth with 2.0 mm dentine ferrule [(758.35+/-19.26) N] and cast metal post-cores restored teeth with 2.0 mm dentine ferrule [(756.63+/-66.22) N] had a significantly greater mean fracture strength than the other three groups in which no significant difference was observed. The 2.0 mm dentine ferrule could cause significant fracture resistance alteration of Celay post-core restored teeth. CONCLUSIONS: When covered with Celay ceramic crowns, Celay post-cores restored teeth with 2.0 mm dentine ferrule and cast metal post-cores restored teeth with 2.0 mm dentine ferrule have similar fracture strength. There was a statistically significant difference between the fracture resistance of Celay post-core restored teeth with and without 2.0 mm dentine ferrule.

Ceramics↗

PubMed2005

[Clinical analysis of diffuse panbronchiolitis in 9 cases with literature review].

OBJECTIVE: To investigate the clinical features and diagnostic procedures for diffuse panbronchiolitis in Chinese patients. METHODS: With literature review, the clinical features and diagnostic procedures of diffusely panbronchiolitis in a series of 9 patients with histopathological confirmation were retrospectively described and discussed. RESULTS: Of the 9 cases, 8 had persistent cough, sputum production and exertion dyspnea, 7 had chronic sinusitis, 9 had centrilobular micronodules on chest CT, 7 had coarse crackles, 4 had FEV(1)/FVC < 70%, 5 had PaO(2) < 80 mm Hg and 1 had titer of cold hemagglutinin > or = 1:64. According to the Japanese revised clinical diagnostic criteria for diffuse panbronchiolitis, definite diagnosis could be made in 4 cases, probable in 3 and excluded in 2 cases, respectively, but it was clinically diagnosed or suspected only in 2 cases before clinicopathological confirmation, the remaining 7 cases were missed or mistaken for other diseases. Of the 9 cases, 8 had received transbronchial biopsy and all showed non-specific inflammation, which was in agreement with but nondiagnostic for diffuse panbronchiolitis. CONCLUSIONS: Most cases of diffuse panbronchiolitis can be clinically diagnosed or suggested according to the clinical diagnostic criteria, proposed solely by Japanese experts which should be further validated in non-Japanese populations. If difficulty in diagnosis arises, the diagnosis of diffuse panbronchiolitis should be based on its clinicopathological features and exclusion of other mimicking diseases. Of note, few cases can be confirmed by transbronchial biopsy, and in this case, surgical lung biopsy should be considered.

Adolescent↗

PubMed2004

Diffuse panbronchiolitis with histopathological confirmation among Chinese.

BACKGROUND: Diffuse panbronchiolitis (DPB) was originally and is still primarily reported in Japan, rarely in other countries. As macrolide therapy is effective for this disease with once dismal prognosis, familiarity with its clinical features is urgently needed, especially for clinicians outside Japan. The objectives of this study were to investigate the clinical features of DPB in a Chinese population and propose diagnostic procedures that will lead to increased awareness of this treatable disease among clinicians, ultimately allowing for more rapid diagnosis. METHODS: After a literature review, the clinical features of DPB were histopathologically confirmed in a series of 9 cases either by open lung biopsy or video-assisted thoracic surgical biopsy, resulting in the largest series of confirmed DPB cases in a non-Japanese population. Here, the cases are retrospectively described and diagnostic procedures are discussed. RESULTS: Persistent cough, sputum, and exertion dyspnea occurred in 89% of patients, a history of or current chronic sinusitis in 78%, centrilobular micronodules appearing on chest CT scans in 100%, coarse crackles in 78%, FEV1/FVC < 70% in 44%, PaO2 < 80 mmHg in 56%, and titer of cold hemagglutinin > or = 1:64 in 11%. According to its clinical diagnostic criteria, diagnosis was definitive in 44%, suggested in 33%, and excluded in 23% at the time of diagnosis. However, DPB was clinically considered before confirmation in only 22% of patients, with the remaining 78% of cases missed or mistaken for other diseases. Of the 9 cases, 8 received transbronchial biopsies before confirmation of the diagnosis, but all showed non-specific inflammation. CONCLUSIONS: Although its clinical features may vary with disease course and ethnic populations, most cases of DPB can be diagnosed or suggested according to clinical diagnostic criteria. However, underdiagnosis as a result of unfamiliarity with its clinical features and diagnostic criteria prevails. If difficulty in diagnosis arises, the diagnosis should be based on clinicopathological features and the exclusion of other diseases. Few cases can be confirmed by transbronchial biopsies; in these cases, either an open-lung biopsy or a video-assisted thoracic surgical lung biopsy should be recommended.

Adolescent↗

PubMed2003

[Thoracic high resolution CT findings of 100 SARS patients in convalescent period].

OBJECTIVE: To study thoracic high resolution CT findings of severe acute respiratory syndrome (SARS) patients in convalescent period and the relationship between the features with laboratory and pulmonary function results. METHODS: All the 100 SARS patients who had been discharged from hospital for about 2 months underwent thoracic high resolution CT examinations. Among them, 65 also had laboratory results and 91 underwent examinations of pulmonary function. RESULTS: Forty-nine SARS patients (49.0%, 49/100) in convalescent period still had abnormal findings in CT examination. And ground-glass opacification (95.9%, 47/49) and reticular opacification (59.2%, 29/49) were common. There was no significant difference in the level of lymphocytes and CD4 cells among groups divided according to severity of CT findings (P > 0.01). Diffusing capacity for carbon monoxide (DLco%) of level 2 and 3 were statistically lower than that of level 0 (P < 0.01). CONCLUSIONS: The features of CT findings of SARS patients in convalescent period are not the same as those of patients in period of apparent manifestation. The high resolution CT can reflect pulmonary diffusing function to some degree.

Adolescent↗

PubMed2003

[Assessment of pulmonary function in SARS patients during the convalescent period].

OBJECTIVE: To investigate the pulmonary function in severe acute respiratory syndrome (SARS) patients during the convalescent period. METHODS: Followup 89 outpatients of SARS. The follow-up study included interview, physical examination, and pulmonary function test. RESULTS: The interval between hospital discharge and functional assessment was 1.75 +/- 0.53 months (0.5-3.4 months). Mild to moderate abnormalities in pulmonary function were found in 48 patients (53.9%). Diffusion capacity for carbon monoxide (DLco) was impaired in 38 patients (42.7%); in 7 patients (7.9%), lung function was restrictive defect combined DLco impairment; Other patterns of impairment were revealed in 3 patient. Dyspnea during acute phase and CT during the convalescent period were found to have significant influences on DLco and total lung capacity (TLC). CONCLUSIONS: Diffusing capacity impairment as well as restrictive defect persist in convalescence SARS.

Adolescent↗