ABSTRACT
BACKGROUND: Poor root canal filling or poor post-core crown restoration can cause microleakage between the implant material and the tooth, leading to secondary infection of the periapical tissue and affecting long-term effect of tooth restoration. OBJECTIVE: To analyze the microleakage in a glucose penetration model when post space preparation is performed with different timing and remaining lengths. METHODS: Eighty-six freshly extracted mandibular premolars from the Orthodontics Department of Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University were randomly divided into eight groups: positive control group (n=10) undertook root canal preparation; negative control group (n=10) undertook root canal preparation and filling but not post space preparation; A1, B1 and C1 groups (n=11 per group) were subjected to root canal filling immediately followed by post space preparation with the filling material of 4 mm, 5 mm, and 6 mm in length, respectively; A2, B2 and C2 groups were subjected to root canal filling and 1 week after filling, the three groups underwent post space preparation with the filling material of 4, 5 and 6 mm in length, respectively. At 48 hours after post space preparation, the integration of root canal wall and filling material was observed by scanning electron microscopy. The glucose microleakage model was used to detect the amount of glucose leaking from the crown to the root in each group. RESULTS AND CONCLUSION: (1) Under the scanning electron microscope, the fillings were most tightly bonded to the root canal wall in C1, while microcracks were most apparent in A2. (2) According to the measurement of glucose penetration model, A2 showed more microleakage than A1 (P < 0.05), B2 showed more microleakage than B1 (P < 0.05), and there was no statistically significant difference between C1 and C2 (P> 0.05). No significant difference was found among A1, B1 and C1 (P> 0.05), B2 showed no statistical difference in the microleakage from A2 and C2 (P> 0.05), but A2 showed more microleakage than C2 (P′ < 0.017). These results indicate that immediate post space preparation is superior to delayed preparation in reducing the microleakage. For immediate post space preparation, the remaining length of the filling material has no effect on the microleakage, but for delayed preparation, the filling material of at least 5 mm in length should be preserved.
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objective: To observe the effectiveness of vertical easy ball attachments (VEBA) in removable partial denture with metal base. Methods: Removable partial denture was retained with one or two sets of VEBA attached to full metal crown or porcelain fused to metal crown in 12 patients and 6～24 month clinical follow up was carried out. Results: All removable partial dentures retained with VEBA had good retention, stabilization, function and esthetic outcome, all the patients were greatly satisfied. Conclusion: VEBA has strong retentive force and protects abutments, it is a promising retainer in removable partial denture.
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Objective:To analyze the prognostic value of the pTNM clinical staying system,as well as the CD57+ cells level in peripheral blood samples of the patients with laryngeal carcinoma.Method:The CD57+ cells level of peripheral blood was determined with SAP method in 34 patients with laryngeal carinoma and 16 normal subjects.The pTNM clinical stage was T1-2in 13,T3-4 in 21;pN+ in 10, pN0 in 24;supraglottis in 8,glottis in 23;hypoglottis in 3;pathologic differentiation G1 in 11,G2,3 in 23.Result:The CD57+ cells level significantly increased (pN+ vs.pNO).In the 12nd month actual survival were significantly different (T1,2 vs.T3,4,pN0 vs.pN+,G1 vs G2、3,supraglottis vs.glottis and hypoglottis,CD57+≥15% vs.CD57+＜15%).In the 24th month and 36th month actual survival were significantly different (pN0 vs.pN+,G1 vs G2、3,supraglotisvs.glottis and hypoglottis,CD57+≥15% vs.CD57+＜15%).In the 48th month actual survival were significantly different only (pN0 vs.pN+,supraglottis vs.glottis and hypo glottis,CD57+≥15% vs.CD57+＜15%).Conclusion:These results suggested that the assessment of pTNM system and the CD57+ cells level have significance for prognosis of patients with laryngeal carcinoma.
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Objective :To properly understand the bacterial distribution and susceptibility to antibiotics in thesinus of nasal sinusitis. Method:The mucosal and secretione in sinus were taken from 135 patients who sufferedwith single nasal sinusitis, by functional endoscopic sinus surgery, were cultured for bacteria. Meanwhile the an-timicrobial susceptibility was determined for ordinary antibiotics. Result: The bacterial growth was present in88.15 % of cases ,mixed bacterial growth was present in 52.10 % of all bacterial ,anaerobe growth was present in39.06％00 of all bacteria． the susceptibility to penicillin was in 53.12%0 of all bacteria and cefaolin was in 87.50%.The susceptibility to metronidazole was in 94.67 % of all anaerobes. Conclusion:We think the method that peni-cillin in combination with streptomycin and metronidazole, sufameth oxazole united with metronidazole, cefaolinadded metronidazole were effective in nasal sinusitis treatment before the antimicrobial susceptive examinationhad been done.