Microtensile bond strengths and scanning electron microscopic evaluation of self-adhesive and self-etch resin cements to intact and etched enamel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Scanning electron microscope evaluation of chlorhexidine gel and liquid associated with sodium hypochlorite cleaning on the root canal walls

Objective. The aim of this study was to evaluate, by scanning electronic microscopy (SEM), the cleaning of the root canal walls after instrumentation and irrigation with 2.5% sodium hypochlorite (NaOCl) associated with 2% chlorhexidine (CHX) gel or liquid, combined or not with 17% ethylenediamine tetra-acetic acid (EDTA).Study design. Sixty single-root human teeth were subjected to standardized root canal instrumentation with different irrigants (n = 10): G1) NaOCl + CHX liquid; G2) NaOCl + CHX liquid + EDTA + saline solution; G3) NaOCl + CHX gel; G4) NaOCl + CHX gel + EDTA + saline solution; G5) saline solution; G6) saline solution + EDTA. After instrumentation, the teeth were prepared for SEM analysis (x500 and x2,000) to evaluate the cleaning of the cervical, middle, and apical thirds. The area analyzed was quantified according to the percentage of open and closed tubules, and data were statistically analyzed by analysis of variance and Tukey tests (P = .05).Results. The number of open tubules was highest in G4 in all root thirds, showing statistically significant difference from G1, G2, and G5 (P < .05). G1 presented higher quantity of closed tubules significant than G2.Conclusion. Irrigation with NaOCl and CHX gel followed by EDTA and saline solution produced greater cleaning of the root canal walls. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:e82-e87)

Label-free DNA detection of hepatitis C virus based on modified conducting polypyrrole films at microelectrodes and atomic force microscopy tip-integrated electrodes

We present a new strategy for the label-free electrochemical detection of DNA hybridization for detecting hepatitis C virus based on electrostatic modulation of the ion-exchange kinetics of a polypyrrole film deposited at microelectrodes. Synthetic single-stranded 18-mer HCV genotype-1-specific probe DNA has been immobilized at a 2,5-bis(2-thienyl)-N-(3-phosphoryl-n-alkyl)pyrrole film established by electropolymerization at the previously formed polypyrrole layer. HCV DNA sequences (244-mer) resulting from the reverse transcriptase-linked polymerase chain reaction amplification of the original viral RNA were monitored by affecting the ion-exchange properties of the polypyrrole film. The performance of this miniaturized DNA sensor system was studied in respect to selectivity, sensitivity, and reproducibility. The limit of detection was determined at 1.82 x 10(-21) mol L-1. Control experiments were performed with cDNA from HCV genotypes 2a/c, 2b, and 3 and did not show any unspecific binding. Additionally, the influence of the spacer length of 2,5-bis(2-thienyl)-N-(3-phosphoryl-n-alkyl)pyrrole on the behavior of the DNA sensor was investigated. This biosensing scheme was finally extended to the electrochemical detection of DNA at submicrometer-sized DNA biosensors integrated into bifunctional atomic force scanning electrochemical microscopy probes. The 18-mer DNA target was again monitored by following the ion-exchange properties of the polypyrrole film. Control experiments were performed with 12-base pair mismatched sequences.

OBSERVATIONS on ETCHED ENAMEL IN NON-ERUPTED DECIDUOUS MOLARS: A SCANNING ELECTRON MICROSCOPIC STUDY

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

PRISMLESS ENAMEL IN HUMAN NON-ERUPTED DECIDUOUS MOLAR TEETH: A SCANNING ELECTRON MICROSCOPIC STUDY

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The use of scaning electron microscopy in postvaccinal evaluation of tracheal epithelium of Coturnix coturnix japonica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Light and scanning electron microscopic study of the palatine mucosa of nine-banded armadillo (Dasypus novemcinctus)

The three-dimensional structure of the lamina propria of the hard and soft palatine mucosa of the nine-banded armadillo was observed by scanning electron microscopy. Sodium hydroxide cell maceration method was applied to demonstrate the architecture of the connective tissue papillae. The palatine mucosa of the armadillo had a triangular shape and measured appr. 6.5 cm length. The hard palate showed 9 transverse palatine plicae while the soft palate was smooth. In the 10% NaOH treated specimens, the lamina propria of the hard palatine mucosa showed numerous connective tissue papillae with a general finger-like shape. These structures were composed by a meshwork of collagen fibers arranged in several directions. on the other hand, the connective tissue papillae of the soft palate mucosa were scattered and small. Numerous openings of glandular ducts with circular or elliptical shape were located in the interplicae area and in the soft palate.

Effects of Nd : YAG laser irradiation on root canal dentin wall: A scanning electron microscopic study

Objective: the purpose of this study was to evaluate, by scanning electron microscopy (SEM), the effects of Nd:YAG laser irradiation applied perpendicular or parallel to the root canal dentin wall. Methods: Thirty human teeth were divided into two groups: Group A (20 roots), laser application with circular movements, parallel to the dentin root surface; and Group B (10 roots), roots cut longitudinally and laser applied perpendicular to the root surface. Group A was subdivided into A1 (10 roots), laser application with 100 mJ, 15 Hz and 1.5 W; and A2 (10 roots) with 160 mJ, 15 Hz, and 2.4 W. Group B was subdivided into B1 (10 hemisections) and B2 (10 hemi-sections) with parameters similar to A I and A2. Four applications of 7-sec duration were performed, with a total exposure of 28 sec. SEM evaluations were made in the cervical, middle, and apical thirds, with 500X and 2000X magnifications. Morphological changes scores were attributed, and the results were submitted to Kruskal Wallis statistical test (5%). Results: Significant statistical differences were found between groups A and B (p = 0.001). In groups A1 and A2, few areas of dentin melting were observed. In groups B1 and B2, areas of melting dentin covering dentin surface were observed. Conclusions: It was concluded that intracanal laser application with circular movements (parallel to the surface) produces limited morphological changes in root canal dentin wall.

Identification of psoralen loaded PLGA microspheres in rat skin by light microscopy

Drug delivery systems involving the use of polymers are widely studied and discovery of biocompatible polymers has become the focus of research in this area. Psoralen loaded poly(DL-lactide-co-glycolide) (PLGA) microspheres to be used in PUVA therapy (psoralen and UVA irradiation (ultraviolet A, 320-400 nm) of psoriasis were identified in paraffin sections by histological analysis. The psoralen loaded PLGA microspheres were prepared using the solvent evaporation technique. They were spherical and possessed an external smooth surface as observed by scanning electron microscopy (SEM) analysis. This study describes a modification in the routine preparation of microsphere samples for examination by light microscopy. The changes involved fixative agents and/or stains allowing the identification of microspheres containing a non-fluorescent material. The preservation and identification of microspheres in tissues for histological processing in paraffin was greatly improved by these modifications as proven by our results. (c) 2007 Elsevicr Ltd. All rights reserved.

A scanning electron microscopic study of the rete testis of the guinea pig

Scanning electron microscopic (SEM) observations of the structure of the rete testis (RT) of guinea pigs preceded by and complemented with stereomicroscopy and light-microscopic studies showed that the RT of this species is predominantly cavitary. An axial and labyrinth-like morphological pattern was also observed in the RT complex, with partially interconnected chambers and epithelium-lined channels accompanying a connective axis observed in the middle portion of the cranial end of the testis. Characteristics of the chordae retis and bullae retis were also visualized in the guinea pig RT and the results are discussed in terms of the morphological patterns observed in the RT of other mammals and of man.

Effects of copper vapor laser radiation on the root canal wall of human teeth: A scanning electron microscope study

Objective: The aim of this study is to analyze the effects of copper vapor laser radiation on the radicular wall of human teeth. Materials and Methods: Immediately after the crowns of 10 human uniradicular teeth were cut along the cement-enamel junction, a chemical-surgical preparation of the radicular canals was completed. Then the roots were longitudinally sectioned to allow for irradiation of the surfaces of the dentin walls of the root canals. The hemi-roots were separated into two groups: one (control) with five hemi-roots that were not irradiated, and another (experimental) with 15 hemi-roots divided into three subgroups that were submitted to the following exposure times: 0.02,0.05, and 0.1 s. A copper vapor laser (510.6 nm) with a total average power of 6.5 W in green emission, frequency of 16.000 Hz, and pulse duration of 30 ns was used. Results: The results obtained by scanning electron microscope analysis showed the appearance of a cavity in the region of laser beam impact, with melting, recrystallization, and cracking on the edges of the dentin of the cavity due to heat diffusion. Conclusions: We determined that the copper vapor laser produces significant morphologic changes in the radicular wall of human teeth when using the parameters in this study. However, further research should be done to establish parameters that are compatible with dental structure in order to eliminate thermal damages. © Mary Ann Liebert, Inc.

Scanning electron microscope analysis of internal adaptation of materials used for pulp protection under composite resin restorations

Purpose: The aim of this study was to evaluate the interfacial microgap with different materials used for pulp protection. The null hypothesis tested was that the combination of calcium hydroxide, resin-modified glass ionomer, and dentin adhesive used as pulp protection in composite restorations would not result in a greater axial gap than that obtained with hybridization only. Materials and Methods: Standardized Class V preparations were performed in buccal and lingual surfaces of 60 caries-free, extracted human third molars. The prepared teeth were randomly assessed in six groups: (1) Single Bond (SB) (3M ESPE, St. Paul, MN, USA); (2) Life (LF) (Kerr Co., Romulus, MI, USA) + SB; (3) LF + Vitrebond (VT) (3M ESPE) + SB; (4) VT + SB; (5) SB + VT; (6) SB + VT + SB. They were restored with microhybrid composite resin Filtek Z250 (3M ESPE), according to the manufacturer's instructions. However, to groups 5 and 6, the dentin bonding adhesive was applied prior to the resin-modified glass ionomer. The specimens were then thermocycled, cross-sectioned through the center of the restoration, fixed, and processed for scanning electron microscopy. The specimens were mounted on stubs and sputter coated. The internal adaptation of the materials to the axial wall was analyzed under SEM with × 1,000 magnification. Results: The data obtained were analyzed with nonparametric tests (Kruskal-Wallis, p ≤ .05). The null hypothesis was rejected. Calcium hydroxide and resin-modified glass ionomer applied alone or in conjunction with each other (p < .001) resulted in statistically wider microgaps than occurred when the dentin was only hybridized prior to the restoration. ©2005 BC Decker Inc.

Scanning electron microscopic analysis of the effect of Carisolv TM gel on periodontally compromised human root surfaces

The aim of this study was to analyze, under scanning electron microscopy (SEM), the morphologic characteristics of root surfaces after application of CarisolvTM gel in association with scaling and root planing (SRP). Sixty periodontally compromised extracted human teeth were randomly assigned to 6 groups: 1) SRP alone; 2) passive topical application of CarisolvTM + SRP; 3) active topical application of CarisolvTM + SRP; 4) multiple applications of CarisolvTM + SRP; 5) SRP + 24% EDTA; 6) topical application of CarisolvTM + SRP + 24% EDTA. CarisolvTM gel was applied to root surfaces for 30 s, followed by scaling and root planing, consisting of 50 strokes with Gracey curettes in an apical-coronal direction, parallel to the long axis of the tooth. The only exception was group 4, in which the roots were instrumented until a smooth, hard and glass-like surface was achieved. All specimens were further analyzed by SEM. The results showed that the treatment with CarisolvTM caused significant changes in root surface morphology of periodontally compromised teeth only when the chemical agent was actively applied (burnishing technique). CarisolvTM failed to remove the smear layer completely, especially with a single application, independently of the method of application. Multiple applications of CarisolvTM were necessary to achieve a smear layer reduction comparable to that obtained with 24% EDTA conditioning.

Scanning electron microscopic and profilometric study of different sharpening stones

Scaling and root planing contribute to the recovery of periodontal health. All periodontal instruments loose their fine cutting angle after use. To maintain this angle, correct sharpening is required using specifically designed stones. The characteristics of sharpening stones can be compared to the blade of the instruments and also transported to root surface during instrumentation. Root smoothness is related to the quality of the blade. Therefore, the purpose of this study was to evaluate the characteristics of 9 sharpening stones by scanning electron microscopic and profilometric analyses. Ceramic and Neumar stones were very fine and both may be recommended to maintain the sharpness of the instruments. Arkansas, Thompson and CE stones presented greater roughness with very regular and round particles, and are suitable for maintenance of the cutting angle. In addition, these stones may be indicated for the routine sharpening of the instruments that are partly dull. Oxide Aluminum, Carborundum and JON stones were the coarsest with large irregular particles and may be indicated for initial sharpening of totally dull instruments with completion of sharpening with finer stones.

Structure and properties of Brazilian peat: Analysis by spectroscopy and microscopy

Peat was taken from the Sergipe State, Brazil and characterized by several techniques: elemental and thermal analyses; Fourier infrared (FTIR) and solid state 13C nuclear magnetic resonance (NMR) spectroscopies; scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM) and X-ray diffractometry (XRD). Also, the Sergipe State peat samples were compared with other peat sample from later from Sao Paulo State, Brazil. The lowest O/C and E 4/E 6 ratios and differential thermal analysis (DTA) curves of the Santo Amaro (SAO) sample indicated that this sample had the highest degree of decomposition. FTIR results showed that Itabaiana (ITA) and São Paulo (SAP) samples presented more prominent peak at 1086 cm -1 attributed the presence of Si-O than SAO sample spectra. The SAO sample showed two more intense peaks at 2920 cm -1 and 2850 cm -1. These results were corroborated by 13C NMR and thermal gravimetric (TG) where the relative abundance of the alkyl-C groups was greater in the SAO sample. The X-ray diffractometry (XRD) of SAO sample is characteristic of amorphous matter however, the SAP and ITA samples revealed the large presence of quartz mineral. The scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM) showed that the surface of peat samples have porous granules of organic material. The ITA and SAP peat samples are alike while SAO peat sample is richer in organic material. Only the SAO sample has truthful characteristics of peat. The results of this study showed that the samples are very different due to variable inorganic and organic material contents. ©2007 Sociedade Brasileira de Química.