1,720,994 research outputs found
A comparative in-vitro study of the bactericidal efficacy of sodium hypochlorite and chlorhexidine gluconate plus cetrimide on root canal anaerobic bacterial flora
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Comparison of the primary stabilities of conical and cylindrical endosseous dental implants: an in-vitro study
No full textThe aim of this study is to determine the differences in primary stability between conical and cylindrical dental implants. The insertion and removal torques were the parameters used to measure the primary stability of the implants. Ten conical and cylindrical dental implants were positioned in polyurethane foam blocks to simulate bone density classes D1, D2, D3 and D4. The insertion and removal torques were quantified using a digital torque gauge. The maximum insertion torque and the maximum removal torque measured for the D1 and D4 synthetic bone were significantly higher for the conical implants than the cylindrical implants. In this in-vitro model, conical implants show significantly higher primary stability than cylindrical implants for the D1 and D4 synthetic bone classes
The relationship between time of re-tightening and preload loss of abutment screws for two different implant designs: an in-vitro study
No full textThe loosening of an abutment screw is one of the most frequent complications in implant-prosthetic rehabilitation, especially for single-crown cemented prostheses. This complication is due to several mechanical factors including type of connection, abutment-screw geometry, settling effects, and cyclical load. The purpose of the present in vitro study was to compare and associate different times of retightening with reductions in preload losses. We evaluated 40 internal hexagon dental implants and 40 external hexagon dental implants, with their related abutment screws. The implants were embedded in acrylic resin in cylindrical polyvinyl chloride tubes (26 mm diameter, 20 mm height). The abutments were fixed to the implants with screws to an initial torque of 35 Ncm using a digital torque meter with decimal precision. Two different types of connection were randomly divided in 4 subgroups of 10 samples each. One subgroup was used as control. The test groups underwent retightening to the same initial torque at increasing times from initial torque application for tightening of the abutment screws, to their retightening at 2 minutes, 5 minutes, and 10 minutes. The retightening time of 2 minutes shows significantly reduced preload loss. Randomized clinical trials are strongly required to provide clinicians with a beneficial standardized protocol of retightening that can be applied in routine clinical practice
Exposure to persistent organic pollutants during tooth formation: molecular mechanisms and clinical findings
No full textPersistent organic pollutants (POPs) constitute a relevant part of environmental pollution. POPs are chemical compounds that persist for a long time in the environment, bio-accumulate in the human body and determine significant adverse consequences to human health. The characteristics of these substances are lipo-affinity, semi-volatility and resistance to the degradation processes. Results deriving from several different studies attest that exposure to the main classes of POPs results in multiple toxic effects on humans and experimental animal models. Among the various alterations caused by exposition to and bio-accumulation of POPs, there are abnormalities in tooth formation and related hard dental tissue structure, especially enamel. This review aimed to describe the close association between the exposure of these compounds during the development of the tooth germ and the occurrence of tooth structural anomalies. Indeed, structural defects of the enamel have as possible consequences higher susceptibility of the tooth to caries disease and higher fragility of the crown to the occlusal trauma
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
COPPER-ZINC SUPEROXIDE DISMUTASE ACTIVITY IN DENTAL PULP AFTER DENTAL PREPARATION
No full textThe superoxide dismutases (SODs) are the major enzymatic defence mechanism against toxic reactive oxygen species generated during normal oxidative metabolism and during the respiratory burst associated with inflammation. To further clarify the potential role of copper-zinc (Cu/Zn)-SOD during inflammation of pulp tissue in humans, the aim was to determine whether significant changes in Cu/Zn-SOD activity occur in healthy dental pulp after dental preparation. The condition of the pulp was assessed using clinical and radiographic evaluation. Thirty systemically healthy patients were the source of the pulp tissue, which was collected by longitudinally grooving and splitting teeth that were matched between the control dental pulp and the prepared tooth (test) dental pulp. Cu/Zn-SOD activity was determined through spectrophotometric methods, with Mann-Whitney tests used to assess the significance of the differences between the groups. The Cu/Zn-SOD activity was 168.2+/-46.4 mU.mg−1 total protein (range: 96-212 mU.mg−1) in the control group, and 328.2+/-84.2 mU.mg−1 total protein (range: 280-420 mU.mg−1) in the test group. The difference between the groups was statistically significant, at P <0.001. These results demonstrate a potential role for Cu/Zn-SOD during dental pulp inflammation in humans after dental preparation
Analysis of professional malpractice claims in implant dentistry in Italy from insurance company technical reports, 2006 to 2010.
No full textPURPOSE:
The aim of the study was to analyze the characteristics of implant dentistry claims in Italy based on insurance company technical reports for malpractice claims.
MATERIALS AND METHODS:
One hundred twenty-one technical reports of cases of professional malpractice in implant dentistry between 2006 and 2010 were included in the study. Data included the sex and age of the patient and dentist, the kind of negligence claimed, and the damages awarded as a consequence of the alleged misconduct.
RESULTS:
Of the cases examined in this study, 9.9% went to court. The patients were female in 73.6% of the cases. Most of the technical errors were committed during implant insertion (82.6%). In 50.4% of cases, the technical error involved the surrounding structures, such as damage to the inferior alveolar nerve (32.2%) or the lingual nerve (2.5%), invasion of the maxillary sinus (9.1%), or pulpal dental necrosis in adjacent teeth (6.6%). Incomplete clinical documentation was apparent in 54.5% of cases. In 9.9% of cases, a civil suit had already been filed before a visit, and medicolegal advice from the insurance expert had been procured
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