ANTIPLAQUE AND ANTIGINGIVITIS EFFECT OF LIPPIA SIDOIDES. A DOUBLE-BLIND CLINICAL STUDY IN HUMANS

Objectives:

The antiplaque and antigingivitis effect of Lippia Sidoides (LS) was evaluated in this in vivo investigation.

Material and Methods:

Twenty-three subjects participated in a cross-over, double-blind clinical study, using 21-day partial-mouth experimental model of gingivitis. A toothshield was constructed for each volunteer, avoiding the brushing of the 4 experimental posterior teeth in the lower left quadrant. The subjects were randomly assigned initially to use either the placebo gel (control group) or the test gel, containing 10% LS (test group).

Results:

The clinical results showed statistically significant differences for plaque index (PLI) (p<0.01) between days 0 and 21 in both groups, however only the control group showed statistically significant difference (p<0.01) for the bleeding (IB) and gingival (GI) index within the experimental period of 21 days. On day 21, the test group presented significantly better results than the control group with regard to the GI (p<0.05).

Conclusions:

The test gel containing 10% LS was effective in the control of gingivitis.     

Effect of peroxide-based bleaching agents on enamel ultimate tensile strength

This study evaluated the effects of peroxide bleaching regimens on the ultimate tensile strength (UTS) of human enamel. A resin composite block was built-up on the bonded occlusal surface of 14 extracted, sound, erupted third molars to enable posterior preparation for the microtensile test. The bonded teeth were serially sectioned in a buccal-lingual direction into approximately 0.7-mm thick slices. Each slice was trimmed with a fine diamond bur to reduce the area of the buccal, internal slope of the cusps to a dumb-bell shape with a cross-sectional area of less than 1 mm2. The samples were randomly divided into seven groups (n = 10): unbleached control group and bleached groups treated with six bleaching regimens. The specimens were tested in tension at 0.5 mm/minute and the data were analyzed by ANOVA and Tukey test. Specimens from the control group presented 51.3 +/- 8.6 MPa, while the UTS of bleached enamel ranged from 22.0 +/- 5.6 to 36.3 +/- 9.1 MPa. All bleaching procedures significantly reduced enamel UTS (p < 0.05). Differences were also observed among treatments. The results suggested that bleaching regimens can significantly reduce enamel UTS.     

CLEANING ABILITY OF CHLORHEXIDINE GEL AND SODIUM HYPOCHLORITE ASSOCIATED OR NOT WITH EDTA AS ROOT CANAL IRRIGANTS: A SCANNING ELECTRON MICROSCOPY STUDY

The aim of this study was to evaluate the cleaning efficacy of 2% chlorhexidine gluconate gel (CHX) compared to 2.5% sodium hypochlorite solution (NaOCl) associated or not with 17% EDTA used as irrigants during the biomechanical preparation. Fifty freshly extracted single-rooted human teeth with complete apex formation were randomly divided into five groups: G1 - sterile saline, G2 - 2.5% NaOCl, G3 - 2% CHX, G4 - 2.5% NaOCl + EDTA and G5 - 2% CHX + EDTA. The specimens of G1 were subdivided into two control groups. The teeth were decoronated and the coronal and middle root thirds were prepared with Gates-Glidden burs, and the apical third was reserved to manual instrumentation. All procedures were performed by a single operator. In all groups, 2 mL of irrigant was delivered between each file change. The teeth were sectioned and prepared for analyses under scanning electron microscopy (SEM). SEM micrographs were graded according to a score scale by two examiners. Data were analyzed statistically by Kruskal-Wallis and Dunn tests at 1% significance level. The best results were obtained in the groups in which the irrigant was used followed by the chelating agent. No statistically significant difference was observed among G4, G5 and the positive control group (p<0.01). The groups G2 and G3 were significantly different from the others, presenting the worst cleaning capacity. In conclusion, the use of the chelating agent is necessary to obtain clean canal walls, with open tubules and no heavy debris. The use of 2% chlorhexidine gluconate gel alone is not able to remove the smear layer.     

The anti-MMP activity of benzalkonium chloride

Objective

This study evaluated the ability of benzalkonium chloride (BAC) to bind to dentine and to inhibit soluble recombinant MMPs and bound dentine matrix metalloproteinases (MMPs).

Methods

Dentine powder was prepared from extracted human molars. Half was left mineralized; the other half was completely demineralized. The binding of BAC to dentine powder was followed by measuring changes in the supernatant concentration using UV spectrometry. The inhibitory effects of BAC on rhMMP-2, -8 and -9 were followed using a commercially available in vitro proteolytic assay. Matrix-bound endogenous MMP-activity was evaluated in completely demineralized beams. Each beam was either dipped into BAC and then dropped into 1 mL of a complete medium (CM) or they were placed in 1 mL of CM containing BAC for 30 days. After 30 days, changes in the dry mass of the beams or in the hydroxyproline (HYP) content of hydrolysates of the media were quantitated as indirect measures of matrix collagen hydrolysis by MMPs.

Results

Demineralized dentine powder took up 10-times more BAC than did mineralized powder. Water rinsing removed about 50% of the bound BAC, whilst rinsing with 0.5 M NaCl removed more than 90% of the bound BAC. BAC concentrations 0.5 wt% produced 100% inhibition of soluble recombinant MMP-2, -8 or -9, and inhibited matrix-bound MMPs between 55 and 66% when measured as mass loss or 76-81% when measured as solubilization of collagen peptide fragments.

Conclusions

BAC is effective at inhibiting both soluble recombinant MMPs and matrix-bound dentine MMPs in the absence of resins.     

Chronology of deciduous teeth eruption in children with cleft lip and palate.

OBJECTIVE: To determine the chronology and sequence of eruption of the deciduous teeth in children with complete unilateral cleft lip and palate. DESIGN: Cross-sectional study. SETTING: Hospital for Rehabilitation of Craniofacial Anomalies, University of Sao Paulo, Bauru, Sao Paulo, Brazil. SAMPLE: A total of 435 children aged 0 to 48 months who presented with complete unilateral cleft lip and palate. RESULTS: All teeth on the cleft side in both jaws for both sexes presented a higher mean age of eruption than their homologues at the noncleft side. This difference was statistically significant for the maxillary lateral incisor, maxillary cuspid, and mandibular lateral incisor. There was a statistically significant sex difference regarding the mean age of eruption only for the maxillary second molar for the girls and mandibular cuspid for the boys. The maxillary lateral incisor on the cleft side was the last tooth to erupt, thus modifying the sequence of eruption of the deciduous teeth. CONCLUSIONS: The results suggest the interference of the cleft on the chronology of eruption of the deciduous teeth that are directly related to it.     

Prevention of hypotension after spinal anaesthesia for caesarean section: a systematic review and network meta-analysis of randomised controlled trials

Spinal anaesthesia for caesarean section commonly causes maternal hypotension. This systematic review and network meta-analysis compared methods to prevent hypotension in women receiving spinal anaesthesia for caesarean section. We selected randomised controlled trials that compared an intervention to prevent hypotension with another intervention or inactive control by searching MEDLINE and Embase, Web of Science to December 2018. There was no language restriction. Two reviewers extracted data on trial characteristics, methods and outcomes. We assessed risk of bias for individual trials (Cochrane tool) and quality of evidence (GRADE checklist). We assessed 109 trials (8561 women) and 12 different methods that resulted in 30 direct comparisons. Methods ranked by OR (95%CI) from most effective to least effective were: metaraminol 0.11 (0.04–0.26); norepinephrine 0.13 (0.06–0.28); phenylephrine 0.18 (0.11–0.29); leg compression 0.25 (0.14–0.43); ephedrine 0.28 (0.18–0.43); colloid given before induction of anaesthesia 0.38 (0.24–0.61); angiotensin 2, 0.12 (0.02–0.75); colloid given after induction of anaesthesia 0.52 (0.30–0.90); mephentermine 0.09 (0.01–1.30); crystalloid given after induction of anaesthesia 0.78 (0.46–1.31); and crystalloid given before induction of anaesthesia 1.16 (0.76–1.79). Phenylephrine caused maternal bradycardia compared with control, OR (95%CI) 0.23 (0.07–0.79). Ephedrine lowered umbilical artery pH more than phenylephrine, standardised mean difference (95%CI) 0.78 (0.47–1.49). We conclude that vasopressors should be given to healthy women to prevent hypotension during caesarean section with spinal anaesthesia.     

Seminal plasma protein networks and enriched functions in varicocele: Effect of smoking

To verify a possible synergistic effect of smoking and varicocele on the seminal plasma proteome and biological functions, a cross-sectional study was performed in 25 smokers and 24 nonsmokers. Samples were used for conventional semen analysis, functional analysis (DNA fragmentation, acrosome integrity and mitochondrial activity) and proteomics by a shotgun approach. Functional enrichment of biological pathways was performed in differentially expressed proteins. Smokers presented lower ejaculate volume (p = .027), percentage of progressively motile spermatozoa (p = .002), total sperm count (p = .039), morphology (p = .001) and higher percentage of immotile spermatozoa (p = .03), round cell (p = .045) and neutrophil count (p = .009). Smokers also presented lower mitochondrial activity and acrosome integrity and higher DNA fragmentation. We identified and quantified 421 proteins in seminal plasma, of which one was exclusive, 21 were overexpressed and 70 were underexpressed in the seminal plasma of smokers. The proteins neprilysin, beta-defensin 106A and histone H4A were capable of predicting the smoker group. Enriched functions were related to immune function and sperm machinery in testis/epididymis. Based on our findings, we can conclude that cigarette smoking leads to the establishment of inflammatory protein pathways in the testis/epididymis in the presence of varicocele that seems to act in synergy with the toxic components of the cigarette.