Clinical performance and failures of zirconia-based fixed partial dentures: a review literature

PURPOSE: Zirconia has been used in clinical dentistry for approximately a decade, and there have been several reports regarding the clinical performance and survival rates of zirconia-based restorations. The aim of this article was to review the literatures published from 2000 to 2010 regarding the clinical performance and the causes of failure of zirconia fixed partial dentures (FPDs). MATERIALS AND METHODS: An electronic search of English peer-reviewed dental literatures was performed through PubMed to obtain all the clinical studies focused on the performance of the zirconia FPDs. The electronic search was supplemented by manual searching through the references of the selected articles for possible inclusion of some articles. Randomized controlled clinical trials, longitudinal prospective and retrospective cohort studies were the focuses of this review. Articles that did not focus on the restoration of teeth using zirconia-based restorations were excluded from this review. RESULTS: There have been three studies for the study of zirconia single crowns. The clinical outcome was satisfactory (acceptable) according to the CDA evaluation. There have been 14 studies for the study of zirconia FPDs. The survival rates of zirconia anterior and posterior FPDs ranged between 73.9% - 100% after 2 - 5 years. The causes of failure were veneer fracture, ceramic core fracture, abutment tooth fracture, secondary caries, and restoration dislodgment. CONCLUSION: The overall performance of zirconia FPDs was satisfactory according to either USPHS criteria or CDA evaluations. Fracture resistance of core and veneering ceramics, bonding between core and veneering materials, and marginal discrepancy of zirconia-based restorations were discussed as the causes of failure. Because of its repeated occurrence in many studies, future researches are essentially required to clarify this problem and to reduce the fracture incident.

A study on factors influencing treatment outcome of failure patients receiving DOTS in a district of West Bengal.

Failure to primary treatment under RNTCP can be an enormous setback for the society. A record based retrospective cohort analysis of 212 patients failing primary treatment under Cat I or Cat III was done in Burdwan district of West Bengal to find the treatment outcome after re-registration under Cat II and its possible influencing factors. Retreatment of failed patients resulted in 24.06% chronicity. Important factors influencing the outcome of being failure were found to be Adolescence (AOR = 2.350; C.I. 0.660-8.281), Urban residence (AOR = 1.878; C.I. 0.705-5.002), primary categorization in Cat I versus Cat III (AOR = 5.036; C.I. 0.897-28.281), higher bacillary load at the beginning of retreatment regimen (AOR = 5.437; C.I. 0.787-37.562) and more than three weeks delay in instituting Cat II treatment (AOR = 3.550; C.I. 0.941- 13.393). 17.35% of such failed patients were still defaulters. Hence such factors may be looked into for more efficient control of Tuberculosis in our country.

Re-pull-through Operation in Hirschsprung's Disease

A re-pull-through operation for Hirschsprung's disease is performed when the primary operation has failed because of the remnant or acquired aganglionosis, anastomotic stricture and/or fistula. The purpose of this study is to review our experience of the re-pull-through procedure for Hirschsprung's disease. From May 1978 to July 2003, 26 patients who underwent re-pull-through operations at the Department of Pediatric Surgery, Seoul National University Children's Hospital, were studied retrospectively by means of chart review as well as telephone interview. The mean age at primary operation and re-operation were 11months (2 months - 10 years) and 43 months (1 year - 23 years 3 months), respectively. Initial operation for Hirschsprung's disease was Duhamel's procedure in 17, Swenson's in 6 and Soave's 3. Causes of failure of primary operation were remains of secondary aganglionic segment (n=23), vascular arcade injury (n=1), rectoperineal fistula (n=2, due to mesenteric torsion and poor blood supply). Mean interval between the primary operation and the re-operation was 34 months (6 months-22 years). Reoperation methods were Soave's in 12, Duhamel's in 8, APSP (abdomino-posterosagittal pull-through procedure) in 5, and Swenson's in 1 case. In 2 cases of repeated rectoperineal fistula or rectourethral fistula, re-APSP were performed 3 times, respectively. A total of 29 re-pull-through operations were performed. Postoperative complications were wound infection (n=1), adhesive ileus (n=1), rectoperineal fistula (n=3), rectourethral fistula (n=2), and death due to pulmonary embolism (n=1). Mean follow up period of reoperation was 78 months (1 month-23years). In current state, 2 patients have an ileostomy because of repeated rectoperineal fistula and rectourethral fistula. Of the remaining 23 patients, 21(91 %) are totally continent with or without minimal soiling. Reoperation for Hirschsprung's disease was effective and safe for the patients complicated to the initial pull-through operation.