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 presence of apical deviation with employment of automated handpieces with continuous and alternate motion for root canal preparation

The present study conducted an in vitro evaluation of the presence of apical deviation on the root canal preparation of the mesiobuccal roots of human maxillary molars employing automated handpieces with continuous motion, the Pow R system (Moyco Union Broach), and alternate motion, the M4 system (Kerr). Analysis of the presence of apical deviation was carried out by means of radiographs obtained on a radiographic desk fabricated for the study. The results demonstrated the lack of statistically significant differences between the two systems as to the evaluation of the presence of apical deviation. There was no correlation between the degree of curvature of the roots and the degree of apical deviation for the continuous motion system. However, there was a statistic difference for the alternate motion system, with a direct correlation of moderate degree.     

Delayed formation of a lower second premolar

Delayed odontogenesis of a lower second premolar is presented in a case treated without extraction and focuses on the 7-year follow-up of the delayed tooth bud. The follow-up was initiated when the crown formation was diagnosed and was finished when the tooth erupted completely into the orthodontically provided space, which enabled the orthodontic leveling and alignment of the delayed premolar. The long follow-up indicates that delayed tooth buds may develop completely and normally.     

Effect of bismuth subgallate (local hemostatic agent) on wound healing in rats. Histological and histometric findings

The aim of this research was to evaluate the effect of bismuth subgallate on wound healing. In 40 Wistar rats, two standard wounds (3.5 mm x 2 mm) were made using a biopsy punch on the back of each animal. Test wounds were filled with bismuth subgallate and control wounds with 0.9% saline. At 1, 4, 7, 11 and 18 days, the qualitative evolution of the granulation tissue morphology was observed and digitalized histologic images were evaluated. There were no significant histological differences between test and control. Histometrically, there were statistically significant differences between test and control (ANOVA--days 1 and 4; Student t test, p < 0.05--days 7, 11 and 18) in terms of the following parameters: area of ulceration--day 1; distance between epithelial edges--day 4; area of granulation tissue--days 7, 11 and 18. It was concluded that bismuth subgallate is biocompatible to the healing tissue, and did not interfere with the normal development of wound healing.     

Effect of surface treatment of a glass-infiltrated alumina ceramic on the microtensile bond strength

This study evaluated the microtensile bond strength of a resin composite to a ceramic submitted to three surface treatments. Twelve glass-infiltrated alumina ceramic blocks (In-Ceram Alumina, VITA) and twelve resin composite blocks (Clearfil APX, Kuraray) with dimensions of 6mm x 6mm x 5mm were made. The surface of the ceramic was wet-grounded with # 600, 800 and 1200-grid sandpaper, and the blocks were divided in three groups: Group 1 - sandblasting with aluminum oxide - particles 110mm (Micro-Etcher, Danville); Group 2 - Rocatec System (ESPE): Tribochemical silica coating (Rocatec pre-powder + Rocatec-Plus powder + Rocatec-Sil); Group 3 - CoJet System (3M/ESPE): silica coating (silica oxide + ESPE-Sil). The ceramic blocks were cemented to the resin composite blocks with Panavia F (Kuraray Co), following the manufacturer's instructions, under load of 750g for 10min. The samples were stored (distilled water / 7 days / 37O C) and sectioned in two axis, x and y, with diamond disk under cooling in order to obtain samples (S) with 0.6 ± 0.1mm2 of adhesive area (n=36). The S were attached in adapted device for the microtensile test that was performed at an universal testing machine (EMIC), at a speed of 1mm/min. The results (MPa) were submitted to ANOVA and Tukey's test (p<0.05): G1 - 15.36; G2 - 30.98; G3 - 31.25. Groups 2 (Rocatec) and 3 (CoJet) presented larger bond strength than group 1. There was no statistical difference between group 2 and group 3.     

A comparison between cutting torque and resonance frequency in the assessment of primary stability and final torque capacity of standard and TiUnite single-tooth implants under immediate loading

PURPOSE: In this study, standard Br?nemark System implants and Br?nemark TiUnite implants were evaluated regarding primary stability and placement torque. The correlation between placement torque and primary stability as well as the influence of implant design on placement torque and primary stability were examined. MATERIALS AND METHODS: Twelve patients who presented bilateral loss of either maxillary lateral incisors or premolars were treated with 24 immediately loaded dental implants. Each patient received 1 standard 3.75 x 13-mm Br?nemark System implant and one 3.75 x 13-mm TiUnite Mk III implant. One at a time, each implant was connected by a transducer to an Osstell machine that automatically translated a resonance frequency value for the implant into an implant stability quotient value. Osseocare equipment was used to measure the placement torque for both types of implants. RESULTS: Statistical analysis showed higher mean values for standard implants in relation to placement torque and resonance frequency values. DISCUSSION: There was no overall correlation between placement torque and resonance frequency values; this finding supported previous studies. CONCLUSION: Stability was shown to be higher for the standard implants. Mean values of torque resistance were higher for the standard implants than for the TiUnite implants. Implant design appeared to influence primary stability and placement torque.     

Effect of microwave treatments on dimensional accuracy of maxillary acrylic resin denture base

Microwave energy has been used as an alternative method for disinfection and sterilization of dental prostheses. This study evaluated the influence of microwave treatment on dimensional accuracy along the posterior palatal border of maxillary acrylic resin denture bases processed by water-bath curing. Thirty maxillary acrylic bases (3-mm-thick) were made on cast models with Clássico acrylic resin using routine technique. After polymerization and cooling, the sets were deflasked and the bases were stored in water for 30 days. Thereafter, the specimens were assigned to 3 groups (n=10), as follows: group I (control) was not submitted to any disinfection cycle; group II was submitted to microwave disinfection for 3 min at 500 W; and in group III microwaving was done for 10 min at 604 W. The acrylic bases were fixed on their respective casts with instant adhesive (Super Bonder) and the base/cast sets were sectioned transversally in the posterior palatal zone. The existence of gaps between the casts and acrylic bases was assessed using a profile projector at 5 points. No statistically significant differences were observed between the control group and group II. However, group III differed statistically from the others (p<0.05). Treatment in microwave oven at 604 W for 10 min produced the greatest discrepancies in the adaptation of maxillary acrylic resin denture bases to the stone casts.     

Effect of Disinfection Treatments on the Hardness of Soft Denture Liner Materials

PURPOSE: To evaluate the effects of disinfection treatments with chemical solutions (2% glutaraldehyde, 5% sodium hypochlorite, and 5% chlorhexidine) and microwave energy on the hardness of four long-term soft denture liners. MATERIALS AND METHODS: Forty rectangular specimens of four soft lining materials (Molloplast-B, Ufi Gel P, Eversoft, and Mucopren soft) were made for each material. Ten samples of each material were immersed in different disinfectant solutions for 10 minutes or placed in a microwave oven for 3 minutes at 500 W. The hardness values were obtained with a Shore A durometer, before the first disinfection cycle (control), and also after two cycles of disinfection. Data were submitted to analysis of variance and Tukey's test (p < 0.01). RESULTS: The highest value of hardness was obtained for Molloplast-B, independent of the disinfection technique. Mucopren soft demonstrated intermediate values and Ufi Gel P and Eversoft the lowest values of Shore A hardness. For Molloplast-B, the disinfection using glutaraldehyde demonstrated the highest value of hardness. The number of disinfections had no effect on the hardness values for all the materials studied and disinfection techniques. CONCLUSIONS: The application of two disinfection cycles did not change the Shore A hardness values for all the materials. The glutaraldehyde solution demonstrated the highest values of Shore A hardness for the Molloplast-B, Mucopren soft, and Ufi Gel P materials, while Eversoft did not present any differences in hardness when submitted to different disinfection treatments.     

In vivo effect of a resin-modified glass ionomer cement on enamel demineralization around orthodontic brackets.

Because the risk of dental caries increases with the use of orthodontic appliances and its control cannot depend only on the patient's self-care, this study evaluated the effect of a glass ionomer cement on reducing enamel demineralization around orthodontic brackets. Fourteen orthodontic patients were randomly divided into 2 groups of 7; they received 23 brackets fitted to their premolars, bonded with either Concise (3M Dental Products, St Paul, Minn), a composite resin (control group), or Fuji Ortho LC (GC America, Chicago, Ill), a resin-modified glass ionomer cement (experimental group). The volunteers lived in a city that has fluoridated water, but they did not use fluoridated dentifrices during the study. After 30 days, the teeth were extracted and longitudinally sectioned; in the enamel around the brackets, demineralization was assessed by cross-sectional microhardness. The determinations were made at the bracket edge cementing limits, and at occlusal and cervical points 100 and 200 microm away from them. In all of these positions, indentations were made at depths from 10 to 90 microm from enamel surface. Analysis of variance showed statistically significant effects for position, material, depth, and their interactions (P<.05). The Tukey test showed that the glass ionomer cement was statistically more efficient than the control, reducing enamel demineralization in all analyses (P<.05). The use of glass ionomer cement for bonding can be encouraged because it decreases the development of caries around orthodontic brackets.     

Supplementation with Herbal Extracts to Promote Behavioral and Neuroprotective Effects in Experimental Models of Parkinson's Disease: A Systematic Review

Parkinson's disease (PD) consists of a neurodegenerative pathology that has received a considerable amount of attention because of its clinical manifestations. The most common treatment consists of administering the drugs levodopa and biperiden, which reduce the effectiveness of the disease and the progress of its symptoms. However, phytotherapy treatment of PD has shown great potential in retarding the loss of dopaminergic neurons and minimizing the behavioral abnormalities. The aim of this study is to systematically review the use of supplemental herbal plants with cellular protective effect and behavioral activity in in vivo and in vitro experimental models. A total of 20 studies were summarized, where the effectiveness of herbal extracts and their isolated bioactive compounds was observed in animal models for PD. The main neurochemical mechanisms found in these studies are schematically represented. The herbal extracts and their biocompounds have antioxidant, anti‐apoptotic, and antiinflammatory properties, which contribute to avoiding neuronal loss. Reports show that besides acting on the biosynthesis of dopamine and its metabolites, these compounds prevent D2 receptors' hypersensitivity. It is suggested that further studies need be conducted to better understand the mechanisms of action of the bioactive compounds distributed in these plants. Copyright © 2017 John Wiley & Sons, Ltd.