Clinical evaluation of the incidence of prosthetic complications in implant crowns constructed with UCLA castable abutments. A cohort follow-up study
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Javier Montero , Guillermo Manzano , David Beltrán , Christopher D. Lynch , María-Jesús Suárez-García , Raquel Castillo-Oyagüe * |
Department of Buccofacial Prostheses, Faculty of Dentistry, Complutense University of Madrid (UCM), Pza. Ramón y Cajal, s/n, E-28040 Madrid, Spain |
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Abstract: (3016 Views) |
Objectives To evaluate the incidence of prosthetic complications in implant-retained crowns made with UCLA castable abutments and to identify possible risk factors with a view to establishing recommendations to help predict the success of such restorations. Methods A cohort follow-up study was carried out in 71 partially dentate patients rehabilitated with 93 implant-retained single crowns. Data regarding socio-demographic background, anatomical features, implant-, and prosthesis-related variables were recorded. The incidence rate (%), relative risk (RR) and odds ratio (OR) were applied for predictive risk factors. ANOVA and Student t-tests were used to compare quantitative variables, the chi-square test was used to compare proportions and also a logistic regression analysis was performed. The statistical significance was set at α=0.05. Results Two implants (2.2%) were lost during the first year of function. The incidence of prosthetic complications in the observed mean period (26.2±15.4 months) was 11.9%, consisting of screw loosening (10.8%) and ceramic fracture (1.1%). A higher tendency for prosthetic complications was noticed in posterior mandibular crowns restoring saddles longer than 10mm with mesiodistal cantilevers longer than 6mm, having natural antagonists, after long-term use (>20 months), with initial torque values superior than 30Ncm. Conclusions Screw loosening is the most frequent complication in implant-retained crowns fabricated with UCLA abutments cast in cobalt–chromium. Nevertheless, the connection usually remains stable after retightening the screws. A high survival rate was recorded, and these prostheses may be a suitable treatment option. Clinical significance Based on the study findings, the risk of prosthetic complications is expected to increase when long-span posterior edentulous areas are rehabilitated with single implant-supported crowns. The antagonist occlusal plane should be restored to prevent torsional forces and overloading. Implant systems with initial torque values less than 30Ncm should be selected.
Source: Journal of Dentistry Full Text |
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Keywords: Dental implants, UCLA castable abutments, Cobalt–chromium, Implant-supported crowns, Screw loosening, Ceramic fracture |
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Type of Study: Research |
Subject:
Prothtodontics Received: 2012/12/18 | Published: 2012/01/15
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