Evaluation of screw loosening on new abutment screws and after successive tightening

This study evaluated the loss of the torque applied after use of new screws and after successive tightening. Four infrastructures (IE), using UCLA castable abutment type, were cast in cobalt-chromium alloy and new abutment screws (G1) were used in a first moment. Subsequently, the same abutment screws were used a second time (G2) and more than two times (G3). The values of the torques applied and detorques were measured with a digital torque wrench to obtain the values of initial tightening loss (%). Data were analyzed by ANOVA and Tukey's test (?=0.05). Significant differences were observed between the G1 (50.71% ± 11.36) and G2 (24.01% ± 3.33) (p=0.000) and between G1 (50.71% ± 11.36) and G3 (25.60% ± 4.64) (p=0.000). There was no significant difference between G2 and G3 (p=0.774). Within the limitations of the study, it may be concluded that the percentage of the initial torque loss is lower when screws that already suffered the application of an initial torque were used, remaining stable after application of successive torques.     

Effect of two axial wall height preparations on the retentive properties of full crowns using three different cements

This study evaluated how different tooth preparation heights and luting cements affected the retention of metallic full crowns. Tooth preparations were made on 60 extracted maxillary premolars with occluso-cervical heights of 4.0 or 5.0 mm. The nickel chromium (NiCr) metallic crowns in each group were subdivided randomly into three groups (n = 10); the samples in each group were cemented with either a self-adhesive resin cement, a conventional resin cement, or a zinc phosphate cement. Cementation was performed by applying 5.0 kg pressure in 50% relative humidity. Specimens were stored in 100% humidity at 37 degrees C for seven days, at which time they were subjected to a vertical tensile test with a universal testing machine at 0.5 mm/min. Data (Kgf) were analyzed by two-way ANOVA and Tukey's multiple comparisons tests (alpha = 0.01). There was a significant difference in mean force in the height preparations (P < 0.001) and in tensile strength (P < 0.001) among the resin cements. Regardless of the cement used, 5.0 mm high preparations showed significantly higher mean forces than the 4.0 mm high preparations. The self-adhesive resin cement showed significantly higher mean tensile strength than the conventional resin cement; the zinc phosphate cement displayed the lowest retention values. The self-adhesive resin cement displayed retention rates twice that of the zinc phosphate cement.     

Gorlin syndrome--case report

The authors present a female case diagnosed with Gorlin syndrome before admission to the Ophthalmology clinic. There are presented types of diagnosis, evolution and treatment in this case.     

Relationship between clinical–radiographic evaluation and outcome of teeth replantation

Abstract –  The aim of this retrospective study was to evaluate clinical and radiographic results related to avulsed and replanted teeth in patients who sought treatment at the Dental Trauma Center of the Dental School of Piracicaba, State University of Campinas, Piracicaba, SP, Brazil. One hundred replanted teeth were studied from 48 individuals (18 females and 30 males, with a mean age of 15 years and 9 months). Post-replantation factors (clinical and radiographic) were observed. The clinical aspects evaluated were crown discoloration, pulp necrosis, mobility changes, presence of fistulae and tooth infra-position. Radiographic examination aimed to identify replacement and inflammatory root resorptions, pulp canal obliteration and the presence of radiolucent areas. Depending on clinical and radiographic findings, results were classified as: complete success, acceptable success, uncertain success or failure. During anamnesis, other factors such as stage of root formation, period extra-alveolar, storage medium, type of splintation, and period after replantation time were recorded. The data obtained were statistically analyzed in order to determine the relationship between the post-replantation factors and outcome of teeth replantation. Linear logistic regression revealed that the majority of replanted teeth were associated with root resorptions and its occurrence duplicated proportionally as the time after replantation increased. Based on these findings, replantation procedures must be submitted to an accurate follow-up, as the success of replanted teeth, which already tends to be limited, may be even more jeopardized if cases are not controlled.     

In vitro evaluation of the susceptibility of endodontic pathogens to calcium hydroxide combined with different vehicles

The aim of this study was to investigate in vitro the antimicrobial activity of calcium hydroxide [Ca(OH)2] in combination with different vehicles against endodontic pathogens. For such purpose, a broth dilution test was performed. Pastes were prepared with Ca(OH)2 powder and the following vehicles: sterile water, glycerin, camphorated monochlorophenol (CMCP), CMCP + glycerin, polyethyleneglycol and CMCP + polyethyleneglycol. The time required for the pastes to produce negative cultures against the tested microorganisms was recorded and analyzed statistically using the Kruskal Wallis test at 5% significance level. Timing for pastes to eliminate the aerobic and facultative anaerobic microorganisms ranged from 6 to 24 h, while strict anaerobic microorganisms were inhibited within 30 s to 5 min. Microbial susceptibility, ranked from weakest to strongest, can be presented as follows: Enterococcus faecalis (the most resistant microorganism), Candida albicans, Staphylococcus aureus, Porphyromonas gingivalis, Porphyromonas endodontalis and Prevotella intermedia (the last two microorganisms required the same time to be eliminated). In conclusion, calcium hydroxide pastes needed more time to eliminate facultative than anaereobic microorganisms. These findings suggest that the antimicrobial property is related both to paste formulation and to microbial susceptibility.     

In vitro evaluation of the antimicrobial activity of chlorhexidine and sodium hypochlorite

The aim of this study was to investigate in vitro the antimicrobial activity of 0.2%, 1%, and 2% chlorhexidine gluconate (CHX gel and CHX liquid), against endodontic pathogens and compare the results with the ones achieved by 0.5%, 1%, 2.5%, 4%, and 5.25% sodium hypochlorite (NaOCl). A broth dilution test was performed, and the timing for irrigants to kill microbial cells was recorded and statistically analyzed. Both 2.0% gel and liquid formulations eliminated Staphylococcus aureus and Candida albicans in 15 seconds, whereas the gel formulation killed Enterococcus faecalis in 1 minute. All tested irrigants eliminated Porphyromonas endodontalis, Porphyromonas gingivalis, and Prevotella intermedia in 15 seconds. The timing required for 1.0% and 2.0% CHX liquid to eliminate all microorganisms was the same required for 5.25% NaOCl. The antimicrobial action is related to type, concentration, and presentation form of the irrigants as well as the microbial susceptibility.     

The glutamate receptor 2 subunit controls post-synaptic density complexity and spine shape in the dentate gyrus

In adult brain the majority of AMPA glutamate receptor (GluR) subunits contain GluR2. In knock-out (KO) mice the absence of GluR2 results in consequences for synaptic plasticity including cognitive impairments. Here the morphology of dendritic spines and their synaptic contacts was analysed via three-dimensional reconstruction of serial electron micrographs from dentate gyrus (DG) of adult wild type (WT) and GluR2 KO mice. Pre-embedding immunocytochemical staining was used to examine the distribution and subcellular localization of AMPA receptor GluR1 and N -methyl- d -aspartate receptor NR1 subunits. There were no significant changes in synapse density in the DG of GluR2 KO compared with WT mice. However, in GluR2 KO mice there was a significant decrease in the percentage of synapses on mushroom spines but an increase in synapses on thin spines. There was also a large decrease in the proportion of synapses with complex perforated/segmented post-synaptic densities (PSDs) (25 vs. 78% in WT) but an increase in synapses with macular PSDs (75 vs. 22%). These data were coupled in GluR2 KO mice with significant decreases in volume and surface area of mushroom spines and their PSDs. In both GluR2 KO and WT mice, NR1 and GluR1 receptors were present in dendrites and spines but there was a significant reduction in NR1 labelling of spine membranes and cytoplasm in GluR2 KO mice, and a small decrease in GluR1 immunolabelling in membranes and cytoplasm of spines in GluR2 KO compared with WT mice. Our data demonstrate that the absence of GluR2 has a significant effect on both DG synapse and spine cytoarchitecture and the expression of NR1 receptors.     

Image-guided study of swine anatomy as a tool for urologic surgery research and training

Purpose:To describe the anatomy of the swine urinary system using computed tomography and to discuss the role of this animal as an experimental model for urological procedures.Methods:Three male Landrace pigs underwent computed tomography and the anatomy of the urinary system and renal circulation was analyzed and described.Results:In all animals, 2 kidneys, 2 ureters and one bladder were identified. Each kidney presented a single renal artery vascularization, with a mean diameter on the right of 4.45 and 5.31 mm on the left (p < 0.0001) and single renal vein drainage, with a mean diameter on the right of 5.78 and 5.82 mm on the left (p = 0.0336). The average renal length was 9.85 cm on the right and 10.30 cm on the left (p < 0.0001). The average renal volume was 113.70 cm³ on the right and 109.70 cm³ on the left (p < 0.0001). The average length of the ureter was 19.78 cm on the right and 22.08 cm on the left (p < 0.0001). The average bladder volume was 423.70 cm³.Conclusions:The data obtained show similarities with human anatomy, suggesting the viability of the swine model for planning preclinical trials, basic research, refinement in experimental surgery and surgical training for urological procedures.Key words: Urologic Surgical Procedures, Tomography, X-Ray Computed, Anatomy, Swine     

Revision rhinoplasty: physician–patient aesthetic and functional evaluation

Introduction

Approximately 5–15% of patients submitted to rhinoplasty operations undergo revision surgery. Those patients have varied functional and aesthetic complaints that should receive a detailed assessment that includes all the expectations the patient had before the previous procedure.