1,721,127 research outputs found
Clinical evaluation of fiber-reinforced epoxy resin posts and cast post and cores
No full textPurpose: This retrospective study evaluated treatment outcome of cast post and core and Composipost systems after 4 yrs of clinical service. Materials and Methods: 200 patients were included in the study. They were divided in two groups of 100 endodontically treated teeth restored with a post. Group 1: Composipost systems were luted into root canal following the manufacturer's instructions. Group 2: Cast post and cores were cemented into root canal preparations with a traditional technique. The patients were recalled after 6 months, 1, 2 and 4 yrs and clinical and radiographic examinations were completed. Endodontic and prosthodontic results were recorded. Results: Group 1: 95% of the teeth restored with Composiposts showed clinical success; 3% of these samples were excluded for noncompliance and 2% showed endodontic failure. Group 2: Clinical success was found with 84% of teeth restored with cast post and core. 2% of these samples were excluded for noncompliance, 9% showed root fracture, 2% dislodgment of crown and 3% endodontic failure. Statistical evaluation showed significant differences between Groups 1 and 2 (P< 0.001). The results of this retrospective study indicated that the Composipost system was superior to the conventional cast post and core system after 4 yrs of clinical service
Clinical studies of fiber posts: a literature review
No full textPurpose: This literature review aimed to find answers to relevant questions regarding the clinical outcome of endontically treated teeth restored with fiber posts. Materials and Methods: All clinical studies published since 1990 in journals indexed in MEDLINE were retrieved by searching PubMed with the query terms "fiber posts and clinical studies." The reference list of the collected articles was also screened for further relevant citations. The strength of the evidence provided by the reviewed papers was assessed according to the criteria of evidence-based dentistry. Results: Five randomized controlled trials (RCTs) on fiber posts have been published in peer-reviewed journals. A meta-analysis is not applicable to these studies since they do not address the same specific clinical question. Retrospective and prospective trials without controls are also available. Conclusions: Two RCTs indicate that fiber-reinforced composite posts outperform metal posts in the restoration of endontically treated teeth. However, this evidence cannot be considered as conclusive. Longer-term RCTs would be desirable. The placement of a fiber-reinforced composite post protects against failure, especially under conditions of extensive coronal destruction. The most common type of failure with fiber-reinforced composite posts is debonding
Resin cement thickness in oval-shaped canals: oval vs. circular fiber posts in combination with different tips/drills for post space preparation
No full textPURPOSE:
To evaluate the cement thickness around oval and circular posts luted in oval post spaces prepared with different drills/tips.
METHODS:
Extracted premolars were endodontically treated and obturated, then randomly divided into three groups (n = 5) according to the tips/drills used for post-space preparation and to the type of fiber post luted: medium grit oval tip + oval posts, fine grit oval tip + oval posts, Mtwo Post File drill + circular posts. The specimens were sectioned in horizontal slices; one slice per canal third was chosen for each post-space, resulting in three slices for each specimen. The distances between the canal wall and the post perimeter were measured on SEM images of each slice.
RESULTS:
The fine grit tip + oval post group obtained statistically significant lower cement thicknesses than the other groups (P < 0.05), in particular in the apical third. The MtwoPF + circular post group showed the highest cement thickness, comparable to that of the medium tip + oval post group. A good post fitting in oval-shaped canals can be obtained using a fine grit oval tip combined with oval posts
Cytotoxicity of dental resin composites: an in vitro evaluation.
No full textResin-based dental restorative materials release residual monomers that may affect the vitality of pulp cells. The purpose of this study was to evaluate the cytotoxic effect of two light-cured restorative materials with and without bis-GMA resin, respectively (Clearfil Majesty Posterior and Clearfil Majesty Flow) and a self-curing one (Clearfil DC Core Automix) when applied to the fibroblast cell line NIH-3T3. Samples of the materials were light-cured and placed directly in contact to cells for 24, 48, 72 and 96 h. Cytotoxicity was evaluated by measuring cell death by flow cytometry, cell proliferation by proliferation curves analysis and morphological changes by optical microscopy analysis. All the composite materials tested caused a decrease in cell proliferation, albeit at different degrees. However, only Clearfil DC Core Automix induced cell death, very likely by increasing apoptosis. Morphological alteration of treated cells was also evident, particularly in the Clearfil DC Core Automix-treated cells. The different cytotoxic effects of dental composites should be considered when selecting an appropriate resin-based dental restorative material for operative restorations
TEM morphological characterization of a one-step self-etching system applied clinically to human caries-affected dentin and deep sound dentin
No full textPurpose: To examine morphologically the hybrid layer of one-step self-etching adhesive, Clearfil S3 Bond (S3bond), in caries-affected dentin (CAD) and deep sound dentin (DSD) cavities performed clinically. For a comparative group, the two-step self etching adhesive Clearfil Protect Bond (Pbond) was used in a similar clinical situation. Methods: This study was carried out on carious and sound teeth clinically selected for extraction. In carious teeth, CAD was obtained by way of subjective criteria by removing infected tissue to form a cavity bottom. DSD was obtained at a depth of 4 mm in the dentin cavity of sound teeth. S3bond and Pbond were applied in the CAD and DSD cavities as indicated by the manufacturer, followed by a composite restoration. Teeth were extracted about 20 minutes after the bonding procedure, and processed for TEM analysis. Results: Expression of S 3bond in CAD was morphologically highly variable. When affected tubules were occluded by intratubular mineralized deposits, the interface displayed a dense poly-HEMA hydrogel as water sorption by the hydrophilic S 3bond toward the porous affected collagen. Conversely, when tubules appeared empty, voids of various sizes were formed by tubular fluid shift. In DSD, S bond clearly exhibited voids and water channels as signs of the high permeability of the sub-surface. Although porosities were somewhat retained, Pbond expression showed a hermetic character which was independent of the dentin substrate. S3bond bonding to dentin was compromised as shown by signs of water movement within the resin/dentin bond outlining a weak capacity to produce an impermeable hybridiztion
Effetto della quantità di tessuti coronali sulla resistenza di denti restaurati con perni.
No full textTEM morphological characterization of a one-step self-etching system applied clinically to human caries-affected dentin and deep sound dentin
No full text"Purpose: To examine morphologically the hybrid layer of one-step self-etching adhesive, Clearfil S3 Bond. (S3bond), in caries-affected dentin (CAD) and deep sound dentin (DSD) cavities performed clinically. For comparative. group, a two-step self etching adhesive, Clearfil Protect Bond (Pbond) was used in a similar clinical situation. Methods:. This study was carried out on carious and sound teeth clinically selected for extraction. In carious teeth, CAD was obtained. by way of subjective criteria by removing infected tissue to form a cavity bottom. DSD was obtained at a depth of 4 mm in. the dentin cavity of sound teeth. S3bond and Pbond were applied in the CAD and DSD cavities as indicated by the. manufacturer, followed by a composite restoration. Teeth were extracted about 20 minutes after the bonding procedure,. and processed for TEM analysis. Results: Expression of S3bond in CAD was morphologically highly variable. When. affected tubules were occluded by intratubular mineralized deposits, the interface displayed a dense poly-HEMA hydrogel. as water sorption by the hydrophilic S3bond toward the porous affected collagen. Conversely, when tubules appeared. empty, voids of various sizes were formed by tubular fluid shift. In DSD, S3bond clearly exhibited voids and water. channels as signs of the high permeability of the sub-surface. Although porosities were somewhat retained, Pbond. expression showed a hermetic character which was independent of the dentin substrate.CLINICAL SIGNIFICANCE: S3bond bonding to dentin was compromised as shown by signs of water movement within the. resin\/dentin bond outlining a weak capacity to produce an impermeable hybridization.
Long term comparative study on the efficacy of one self-adhesive composite in dental hypersensitivity
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