High occurrence of ß-lactamase-producing Salmonella Heidelberg from poultry origin.

Salmonella Heidelberg is commonly reported in foodborne outbreaks around the world, and chickens and poultry products are known as important source of these pathogen. Multidrug-resistant S. Heidelberg strains are disseminated into poultry production chair, which can lead to severe clinical infections in humans and of difficult to treat. This study aimed at evaluating the ß-lactam susceptibility and genotypic relatedness of Salmonella Heidelberg at Brazilian poultry production chain. Sixty-two S. Heidelberg strains from poultry production chain (poultry, poultry meat and poultry farm) were used. All strains were evaluated to antimicrobial susceptibility by diffusion disk test, as well as ß-lactam resistance genes. Genotypic relatedness was assessed by Pulsed-Field Gel Eletrophoresis, using Xba1 restriction enzyme. Forty-one strains were characterized as multidrug-resistant according to phenotype characterization. The resistance susceptibility revealed 31 distinct profiles, with higher prevalence of streptomycin (61/62), nalidixic acid (50/62), tetracycline (43/62) and ß-lactam drugs (37/62). blaCMY-2 was the more frequent ß-lactamase gene found (38/62); other resistance genes found were blaCTX-M (2/62), blaSHV (3/62) and blaTEM-1 (38/62). No carbapenemase genes was found. The Pulsed-Field Gel Electrophoresis showed 58 different profiles. Strains with a larger number of antimicrobial resistance were grouped into ten major clusters apart from others. The spread of resistance by ampC continues to rise, thereby turning concern to public health, since the ß-lactam antimicrobials are used as a therapeutic treatment in humans.

Remineralization effect of CPP-ACP and fluoride for white spot lesions in vitro.

OBJECTIVES: This in vitro study compared the remineralization effect on white spot lesions of casein phosphopeptide-amorphous calcium phosphate crème, or CPP-ACP (MI Paste™), 1.1% NaF dentifrice containing 5000ppm of fluoride (ControlRX™), or CPP-ACP crème with 900ppm of fluoride (MI Paste Plus™) with that of a control. METHODS: Artificial white spot lesions were created on smooth enamel surfaces of sound molars using a previously reported demineralization model. Specimens were randomly assigned to four treatments (n=35) with a pH-cycling model over 30 days: Control (no treatment); MI Paste (10% CPP-ACP crème); F5000 (1.1% NaF dentifrice); or MI Paste Plus (10% CPP-ACP plus 900ppm fluoride crème). Products were applied following manufacturers' directions. Changes in mean lesion depth expressed by percent fluorescence loss (ΔF%), and lesion area (mm(2)) from baseline to after treatment were measured with light-induced fluorescence (QLF). Mean values of each parameter were compared between groups (p<0.05). RESULTS: The remineralization pattern for the F5000 group was unique with marked initial remineralization during the first 10 days and little subsequent change. Based on mean lesion area, the F5000 demonstrated greater remineralization than Control, MI Paste and MI Paste Plus groups. Based on mean fluorescence loss, the F5000 group showed improved remineralization relative to MI Paste Plus, but did not differ statistically from the Control at the end of 30 days. CONCLUSIONS: The 1.1% NaF dentifrice demonstrated overall greater remineralization ability than 10% CPP-ACP crème. However, the 1.1% NaF dentifrice was only as effective as the Control to reduce fluorescence loss. CLINICAL SIGNIFICANCE: This study showed that a 1.1% NaF dentifrice (5000ppm) demonstrated greater remineralization ability than the CPP-ACP topical tooth crème and that the addition of fluoride to its formulation seems to enhance remineralization. Saliva also has the ability to exert an important remineralization effect over time.

Implementation of a laboratory quality assurance program: the Louisville experience.

Remakes, or the refabrication of dental prostheses, can occur as a result of inherent inaccuracies in both clinical and laboratory procedures. Because dental schools manage large numbers of predoctoral dental students with limited familiarity and expertise as related to clinical prosthodontic techniques, it is likely these schools will experience an elevated incidence of laboratory remakes and their ramifications. The University of Louisville School of Dentistry, not unlike other dental schools, has experienced remakes associated with both fixed and removable prosthodontic procedures. Limitations in faculty standardization and variable enforcement of established preclinical protocols have been identified as variables associated with the high percentage of remakes documented. The purpose of this study was to introduce the implementation of a new multidepartmental quality assurance program designed to increase consistency and quality in both information provided to commercial dental laboratories and the prostheses returned. The program has shown to be advantageous in terms of cost-effectiveness and treatment outcomes. A statistically significant decrease in remake percentages has been recorded from inception of this program in December 2010 until December 2012. Furthermore, this program has resulted in more consistent communication between the dental school and commercial dental laboratories, among faculty members, and between faculty and students.

Safety and efficacy of a high-adhesion whitening strip under extended wear regimen.

OBJECTIVES: This randomized, parallel group, single centre clinical trial was conducted to evaluate the safety and compare the whitening efficacy for an extended wear of an experimental 9.5% H2O2 high-adhesion whitening strip, relative to a marketed 10% H2O2 control strip. METHODS: Twenty-nine eligible adult volunteers were randomly assigned to either a treatment series with an experimental 9.5% H2O2 high-adhesion whitening strip at home for 2h, once a day, for 8 days; or a marketed 10% H2O2 whitening strip for 30 min, on a similar daily regimen. Tooth color/whitening progression was recorded under standardized lighting conditions at baseline, day 3, day 5, and day 9, via digital imaging. Outcomes were reported using the CIELAB system. Usage safety was also assessed at each follow-up visit. Whitening efficacy for each group was investigated using a paired-difference t-test. The treatment groups were compared among each other using the analysis of covariance, with the baseline value and age as the covariates. RESULTS: Both treatment groups demonstrated statistically significant mean color improvement from baseline for b* (yellow ness) and L* (lightness) at each post-baseline visit. In addition, the 2-h high-adhesion strips demonstrated significantly greater improvement in b* and L* relative to the 30-min strip group at each follow-up visit. CONCLUSIONS: The 2-h regimen for the 9.5% H2O2 high-adhesion whitening strip was more efficient for tooth whitening than the 30-min regimen of 10% H2O2 whitening strip. Both treatments were well tolerated and the use of the test products during the study time frame was considered safe. CLINICAL RELEVANCE: Extending the daily wear time of whitening strips can improve the efficacy of the treatment and ultimately shorten the length of the treatment without any significant adverse effects.

Influence of tooth age and etching time on the microtensile bond strengths of adhesive systems to dentin.

PURPOSE: 1. To evaluate the effect of tooth age on the microtensile bond strengths (µTBS) of various adhesive systems to dentin; 2. To evaluate the effect of different etching times on the microtensile bond strengths of different adhesive systems to young vs mature dentin. MATERIALS AND METHODS: One hundred twenty intact human teeth were mechanically ground to expose midcoronal dentin and were randomly assigned to three groups (n = 40) according to subjects' age in years: 15 to 25, 35 to 45, and >= 55. Within each group, specimens were further randomized into 8 subgroups according to adhesive (etch-and-rinse 3- and 2-step; self-etching 2- and 1-step) and etching time (manufacturer instructions vs extended). Resin composite was applied to the treated surfaces, and after 24 h, all specimens were processed for microtensile bond strength testing. Data were analyzed by factorial ANOVA and Tukey's test (p = 0.05). RESULTS: µTBS values ranged from 10.9 MPa (2-step self-etching, extended etching time, age group 15 to 25) to 50.7 MPa (1-step self-etching, extended etching time, age group >= 55). With only one exception, tooth age and etching time had no significant effect on the bond strengths of the adhesives to dentin. The 2-step self-etching system had lower bond strengths than the other systems, regardless of etching time or tooth age. CONCLUSION: Tooth age and etching time did not affect the dentin bond strengths of the adhesives tested.

Crown fragment reattachment: report of an extensive case with intra-canal anchorage.

This paper describes the resolution of an extensive complicated crown-root fracture of an endodontically treated maxillary central incisor. Initially, the fractured crown was splinted to the adjacent teeth with orthodontic wire and composite resin. Subsequently, the crown fragment was reattached by means of a fiber post using a hybrid composite resin. Early stage success was achieved with the observance of normality in function, esthetics, and health of the tooth and surrounding periodontal structures. An athletic mouthguard was fabricated to prevent further trauma. Advantages, disadvantages, and prognosis of the treatment presented are discussed.

Adhesive bond strengths using self- and light-cured composites.

AIM: To evaluate the microtensile bond strength (microTBS) of four adhesive systems to dentin, using self- and light-cured resin composites. METHODS AND MATERIALS: Crowns of human molars were separated from the roots, and the occlusal surfaces were ground to obtain flat superficial dentin. Three etch-and-rinse adhesives--All-Bond 2, One-Step Plus, and OptiBond Solo Plus--and one self-etching primer system, Peak SE, were evaluated. Each adhesive group was divided into two subgroups according to the type of resin composite used. A self-cured (Bisfil 2B) or light-cured (Filtek Supreme Plus) resin composite build-up was incrementally inserted to the dentin after each adhesive system was applied. The bonded specimens were stored in water for 24 h and sectioned into beams. Microtensile testing was done, and the data were subjected to ANOVA and Fisher's PLSD test. RESULTS: The microTBS of All-Bond 2 and One-Step Plus was not affected by the type of resin composite used (p=0.3131 and p=0.1562, respectively). The microTBS of OptiBond Solo Plus was significantly reduced when used with self-cured resin composite (p<0.0001). Peak SE formed no bond of self-cured resin composite to dentin. CONCLUSION: Some adhesives do not effectively bond self-cured resin composite to dentin. CLINICAL SIGNIFICANCE: Incompatibility between adhesives with low pH and certain self-cured resin composites can cause clinical debonding of restorations.

Composite resin restorations of permanent incisors with crown fractures.

The composite resin restoration of permanent incisors with crown fractures is a conservative, timely, and economical treatment option. Several variables can affect the longevity of this type of restoration including: the overall prognosis of the injured tooth, whether the pulp is exposed, the extent of the crown fracture, the restoration's size, the patient's age and occlusion, and future reinjury of the restored tooth. Contemporary adhesives and composites allow clinicians to restore fractured permanent incisors with good predictability, restoring both the esthetics and function of the affected tooth. The purpose of this paper is to discuss the current state of the restoration of permanent incisors with crown fractures using composite resins.