Canal disinfection using photo-chemically activated micro-bubble emulsion, Emblica officinalis, and Nd: YAP laser on smear layer and push-out bond strength of resin-based root canal sealer to the radicular dentin.

AIMS: Evaluation of the effects of the latest root canal disinfectants i.e., Micro-bubble emulsion (MBE), Neodymium-doped yttrium aluminum perovskite (Nd: YAP), Emblica officinalis (E. officinalis) on the removal of smear layer (SL) and push out bond strength (PBS) of resin-based root canal sealer to the radicular dentin. METHODS: The coronal portion of sixty single-rooted human mandibular premolar teeth was precisely sectioned at the cementoenamel junction. The canals were prepared to utilize ProTaper universal rotary files till F3. All the study specimens were divided into four groups based on the disinfection regime (n = 15) Group 1: 5.25% NaOCl, Group 2: MBE, Group 3: Nd: YAP laser and Group 4: E. officinalis extract. All the canals were then finally irrigated using 17% EDTA solution as a final disinfecting agent. SL removal assessment was performed on five samples from each group using a scanning electron microscope (SEM). Ten samples from each group were then filled with root canal filling material and the roots were sectioned. Push-out test and failure mode analysis were performed using the universal testing machine (UTM) and stereomicroscope respectively. The mean scores of PBS and SL removal were compared using a one-way analysis of variance (ANOVA) and Post Hoc Tukey's HSD test p = 0.05. RESULTS: Group-2 (MBE + EDTA) coronal section (1.50 ± 0.23) exhibited the most effective eradication of SL from the canal space. The apical third of Group-1 (NaOCl+EDTA) (2.68 ± 0.82) samples demonstrated the least effective removal of SL from the radicular canal. The maximum score of PBS of AH plus sealer to the canal dentin was exhibited by the coronal section of Group-2 (MBE + EDTA) (9.55 ± 0.45 MPa) samples. However, the apical third of Group-1 (NaOCl+ EDTA) specimens (5.16 ± 0.32 MPa) demonstrated the minimum EBS. CONCLUSION: MBE+ EDTA displayed better smear layer removal and bond integrity of AH plus sealer to the root canal dentin. Nd: YAP+ EDTA laser and E.officinalis displayed comparable outcomes to that of control NaOCl+ EDTA.

Metabolic and ultrastructural renal changes in adult Wistar rats fed by a cafeteria diet

ABSTRACT Purpose: To evaluate, by quantitative and qualitative methods, the glomerular ultrastructure in Wistar rats fed a cafeteria diet. Methods: Male Wistar rats were divided into two groups at 21 days of age: control (C, n = 10) and cafeteria diet (CAF, n = 8). The animals were followed up until 5 months of age, followed by euthanasia. The blood, kidneys, and fat deposits--epididymal, retroperitoneal, and subcutaneous--were extracted and analyzed. Data were analyzed by Student's t test, and p < 0.05 was considered statistically significant. Results: The cafeteria diet promoted glucose intolerance, hyperglycemia (p < 0.0001), and deposition of retroperitoneal fat (p < 0.005). Scanning electron microscopy revealed that the length of the foot process was similar in both groups. The quantitative analyses by transmission electron microscopy revealed that the cafeteria diet reduced the thickness of the glomerular basement membrane (p < 0.05). Conclusions: The intake of lipids and simple carbohydrates were found to be associated with alteration in the glomerular ultrastructure. However, more studies are needed to evaluate not only the effects of high-protein and high-fat diets on components of the glomerular filtration barrier, but also renal physiology.

Does the combination of whitening toothpaste and hydrogen peroxide bleaching increase the surface roughness and change the morphology of a nanofilled composite?

Aim: To evaluate changes in the surface roughness and morphology of a nanofilled composite following toothbrushing with a whitening (WT) or regular toothpaste (RT), alone or combined with 35% hydrogen peroxide bleaching (HP). Methods: Seventy disc-shaped nanofilled composite (Filtek Z350XT) specimens were randomly divided into groups (n=10): WT, RT, TB (without toothpaste ­ control) or the combinations WT/ HP, RT/HP, TB/HP and HP. All groups underwent toothbrushing simulation (60,000 cycles) and bleaching treatment (4 sessions). Mean surface roughness (Ra, µm) was measured before (T0) and after treatments (TB). Surface morphology was assessed by scanning electron microscopy (SEM) at TB. Mean Ra was analyzed using general mixed models and multiple comparisons by the Tukey-Kramer test (α=5%). Results: HP caused no surface roughness changes on the nanofilled composite after treatment (p>0.05). RT toothbrushing, combined or not with HP, increased the surface roughness (p<0.05). WT and WT/ HP protocols had no effect on the surface roughness of the composite (p>0.05). The nanofilled composite submitted to RT toothbrushing combined with HP (RT/HP) presented substantial surface alterations under SEM, showing deep depressions and round-shaped defects. Toothbrushing with RT combined with the bleaching agent increased exposure of the inorganic fillers. Conclusion: WT toothbrushing, regardless of HP combination, or the single HP protocol had no effect on the surface roughness of the nanofilled composite. However, RT combined with HP negatively affected surface roughness and presented the most noticeable surface changes among groups

EFFECTS OF PROFESSIONAL ORAL HYGIENE AND TEETH WHITENING ON THE MICROELEMENT COMPOSITION OF ENAMEL.

OBJECTIVE: Aim: The objective of this study is to investigate the impact of professional teeth cleaning and the substances used in modern dentistry for whitening on the microelement composition of tooth enamel. PATIENTS AND METHODS: Materials and Methods: To study the morphology and microelement composition of the enamel, scanning electron microscopy was performed using the MiraLM microscope equipped with a Schottky field emission electron gun from Tescan. RESULTS: Results: A comparative analysis between the areas subjected to mechanical cleaning and those where it was not applied revealed a significant difference in the research results, particularly in carbon, which changed from 25.16±1.04 to 32.02±1.8. An analysis of the enamel's chemical composition before and after whitening revealed a decrease in carbon from 45.91±1.20 to 42.46±1.74. The change in phosphorus content was determined to be from 9.77±0.39 to 9.56±0.75. A decrease in calcium from 15.96±0.64 to 15.21±1.22 and magnesium from 0.07±0.01 to 0.01±0.01 was also observed. CONCLUSION: Conclusions: Professional dental hygiene does not have a direct impact on the microelement composition of enamel, such as the levels of calcium, phosphorus, fluoride, and other microelements. However, it can have an indirect and temporary influence due to the use of abrasive materials that affect dental deposits, pellicle, and the surface layer of enamel. Teeth whitening can affect the microelement composition of enamel, but these changes are mostly temporary and associated with processes of demineralization/ remineralization and oxygenation.

Effect of blood contamination on marginal adaptation of cold ceramic and MTA angelus: a scanning electron microscopic study.

BACKGROUND: This study aimed to assess the effect of blood contamination on marginal adaptation of cold ceramic (CC) and mineral trioxide aggregate (MTA) Angelus using scanning electron microscopy (SEM). METHODS: This in vitro experimental study was conducted on 24 extracted single-rooted human teeth. After cleaning and shaping, the root canals were filled with lateral compaction technique. The apical 3 mm of the roots was cut, and cavities with 3 mm depth were created at the apex. The teeth were randomly assigned to two group (n = 12) for the application of CC and MTA Angelus as retrograde filling materials. CC and MTA Angelus were prepared by mixing the powder with blood, and applied in the cavities. After 24 h, their marginal adaptation to the canal walls was assessed by SEM. Data were statistically analyzed by t-test (alpha = 0.05). RESULTS: The mean marginal gap was 8.98 µm in the CC, and 16.26 µm in the MTA Angelus group; this difference was statistically significant (P < 0.001). CONCLUSIONS: The present in vitro study revealed that following complete blood contamination of powder, CC showed significantly superior marginal adaptation than MTA Angelus as shown by SEM assessment.

The red ruffed lemur, Varecia rubra (É. Geoffroy Saint-Hilaire, 1812): a comparative morphology investigation of lingual papillae and connective tissue cores.

The morphology of the lingual papillae (filiform, foliate, fungiform, and vallate papillae) and the underlying connective tissue core of the red ruffed lemur (Varecia rubra) of a strepsirrhines species were studied using light and scanning electron microscopy. The filiform papillae distributed at the root of the tongue were larger than the structures distributed at the body and apex. Six to eight vallate papillae were arranged in a Y-shape at the border between the lingual body and the lingual root. Foliate papillae were observed at the posterior lateral border of the tongue. Scanning electron microscopy revealed a primary process and numerous auxiliary processes in the epithelial layer of filiform papillae. After epithelial removal, the connective tissue core of the filiform papilla showed several protrusions surrounding an oval-shaped depression that extended slightly posteriorly, and a large, maple-shaped filiform papilla was seen in the posterior portion of the tongue. The connective tissue cores of the fungiform papillae exhibited a longitudinally ridged cylindrical structure. The connective tissue core of the foliate papillae had numerous tubular projections arranged along a groove with a salivary gland conduit at the base. As a Lemuridae species, the appearance of the fungiform and filiform papillae of the red ruffed lemur is similar to that reported in previous studies of the ring-tailed lemur, with some differences, especially in the filiform papillary connective tissue core at the base and tongue body border. These findings suggest the taxonomic and phylogenetic origins of the lemurs as well as the influence of dietary diversity.

Evaluation of the Efficacy of CPP-ACP Remineralizing Mousse in Molar-Incisor Hypomineralized Teeth Using Polarized Raman and Scanning Electron Microscopy-An In Vitro Study.

Remineralization of tooth enamel can be achieved by applying a complex of casein phosphopeptides and amorphous calcium phosphate (CPP-ACP). However, the efficacy and optimization of this agent in molar−incisor hypomineralization (MIH) lacks evidence. The purpose of this study is to evaluate the efficacy of CPP-ACP tooth mousse in remineralizing MIH-affected enamel in an optimized 28-day protocol using polarized Raman microscopy and scanning electron microscopy. The protocol was applied to two types of MIH opacities, white and yellow, and compared against sound enamel specimens before and after treatment. Data was analyzed using a one-way ANOVA and LSD post hoc multiple comparisons test (p < 0.05) for the Raman analysis. Hypomineralized enamel showed an improvement of its structure after CPP-ACP supplementation. In addition, Raman spectroscopy results showed a decrease in the depolarization ratio of the symmetric stretching band of phosphate (p < 0.05 for both groups). In conclusion, there was an improvement in mineral density and organization of the hypomineralized enamel after treatment with CPP-ACP tooth mousse.

Cleaning of long oval canals with WaveOne Gold system associated with different irrigant agitation protocols

Aim: The aim of the study was to evaluate the cleaning of mandibular incisors with WaveOne Gold® (WO) under different preparation techniques. Methods: A total of 210 human mandibular incisors were selected and divided into seven groups (n = 30), prepared by WO single-files (Small 20/.07 ­ WOS; Primary 25/.07 ­ WOP; Medium 35/.06 ­ WOM; or Large 45/.05 - WOL) and sequential-file techniques (WOS to WOP; WOS to WOM; and WOS to WOL). Further subdivision was made according to irrigation protocol: control group (manual irrigation - CON), E1 Irrisonic® - EIR, and EDDY® - EDD. Debris removal and the smear layer were evaluated by scanning electron microscopy. Data were analyzed by using Spearman's correlation test. The significance level was set at 5%. Results: For debris and smear layer removal, WOS and WOP, EIR differed from CON and EDD (p <0.05). Conclusion: Regardless of the instrumentation used, the agitation of the irrigant solution provided better cleanability. These findings reinforce the need for agitation techniques as adjuvants in cleaning root canal systems in mandibular incisors

Surface characterization of indirect restorative materials submitted to different etching protocols.

OBJECTIVES: This in vitro study aimed to evaluate the effect of different times and concentrations of hydrofluoric acid etching on the surface of indirect restorative materials obtained from blocks used in CAD-CAM technology. METHODS: Specimens (4 mm × 4 mm × 0.8 mm) were obtained for each indirect restorative material: zirconia-reinforced lithium monosilicate ceramic (Celtra Duo), nanoceramic resin (Lava Ultimate), and polymer-infiltrated ceramic network material (Vita Enamic). The materials were submitted to etching with 5% or 10% hydrofluoric acid for 20, 40, 60, or 90 s. A control group for each material was evaluated without any surface treatment, totaling nine experimental groups for each material (n = 10). The specimens were evaluated for surface roughness (Ra and Rz), confocal optical microscopy, the contact angle (θ), surface free energy (γs), total free interaction energy (∆G) using a goniometer, and microshear bond strength to resin cement. Specimen images were obtained using scanning electron microscopy, confocal optical microscopy, and atomic force microscopy. Data on the surface roughness, the contact angle, surface free energy, total free interaction energy, and bond strength were subjected to two-way ANOVA and Tukey´s test (α=0.05). RESULTS: In general, Celtra Duo showed better results after etching with 10% hydrofluoric acid for 40 or 60 s. Lava Ultimate showed better performance after etching with 10% hydrofluoric acid for 20 or 40 s, whereas Vita Enamic showed better results after etching with 5% hydrofluoric acid for 90 s. CONCLUSION: Each material showed different characteristics after etching with hydrofluoric acid. Knowledge of the proper protocol for each material is essential to ensure improvements in the adhesion process and durability of indirect restorations. In general, Celtra Duo presented mechanical properties superior to those of Lava Ultimate and Vita Enamic. CLINICAL SIGNIFICANCE: Specific etching protocols must be recommended for each indirect material because longer exposure to hydrofluoric acid can jeopardize the surface, thus affecting the mechanical and bond strength properties.

Acanthocytes Identified in Huntington's Disease.

Background: Neuroacanthocytosis (NA) and Huntington's disease (HD) are neurodegenerative conditions that share clinical symptoms and imaging findings, despite their distinct genetic etiologies. Usually, the presence of acanthocytes can help narrow the differential diagnosis of a familial choreiform disorder, as the diagnosis of NA syndrome is supported by the presence of acanthocytes in peripheral blood. In this study, we demonstrate four patients who present with HD and acanthocytosis. Methods: We retrieved the data of 40 HD patients with fresh peripheral blood screened for erythrocytes in our hospital from 2014 to 2022. Of these 40 patients, four patients with acanthocytes were recruited for this study. Patients' investigations included clinical and laboratory studies, HTT gene sequencing, and whole-exome sequencing. Fresh peripheral blood was screened for erythrocytes by scanning electron microscopy. Results: The four adult patients were Han Chinese and unrelated. The age ranged from 45 to 61 years, with a disease duration of 4-10 years. The main neurological features at diagnosis included progressive involuntary movements, psychiatric changes, and dementia. Genetic analysis showed an expansion at the HTT gene. The mean proportion of acanthocytes was mild (6-10%) elevated in patient one and high (>20%) elevated in patients 2-4 by scanning electron microscopy examination. Conclusion: Our study illustrates that HD can combine with acanthocytosis, which may expand the clinical phenotype. Even though the primary gene defect appears to be predominately directed at the brain, a peripheral defect can be seen in HD. Our study highlights the complexity and diversity of HD.

Blood cell adhesion to arterial filters analysis by scanning electron microscopy and real-time PCR assay: observational clinical study in cardiac surgery patients.

INTRODUCTION: Arterial filter is the part of the cardiopulmonary bypass circuit where blood cells are exposed to high mechanical stress and where cellular aggregates may fasten in large quantities. The aim of this study was to analyse blood cell adhesiveness in the arterial filter through scanning electron microscopy and real-time PCR assay. METHODS: Prospective, clinical and observational study performed on 28 patients undergoing cardiac surgery with cardiopulmonary bypass. Arterial filters were analysed by scanning electron microscopy. Real-time PCR assay was performed in extracted material from the arterial filters for analysis of platelet GPIb and CD45 leucocyte gene expression. Blood coagulation was analysed during cardiopulmonary bypass. Patients were followed until hospital discharge or 28 days after surgery. RESULTS: All studied arterial filters used in the subject patients showed a degree of adhesion from blood elements at scanning electron microscopy. All studied filters were positive for platelets GPIb gene expression and 15% had CD45 leucocyte gene expression. The GPIb platelet gene expression in blood lowered at the end of cardiopulmonary bypass (p = 0.019). There was negative correlation between blood GPIb platelet gene expression and Clot SR (HEPSCREEN2 ReoRox®) (rho = 0.635; p = 0.027). The filter fields count was correlated to the D-dimer dosage (rho = 0.828; p < 0.001). CONCLUSION: There was adhesion of blood elements, especially nucleated platelets, on all arterial filters studied. Although the arterial filter worked as a safety device, that possibly prevented arterial embolisation, it may also have caused greater hyperfibrinolysis during cardiopulmonary bypass.

Heat-treated NiTi instruments and final irrigation protocols for biomechanical preparation of flattened canals

Abstract This study evaluate shaping ability of heat-treated NiTi-alloy instruments associated with different final irrigation protocols in flattened root canals. Thirty human mandibular incisors with flattened root canals were divided into 5 groups (n = 10): (XP) Original Protocol XP-endo Shaper; (XP-WT) Original Protocol XP-endo Shaper with working time variation; (XP-K) XP-endo Shaper with kinematics variation; (XP-WTK) XP-endo Shaper with kinematics and working time variations; (Hyflex) Hyflex CM. For the variation in working time protocols the same sample of the XP-endo Shaper groups with and without kinematic variation were used. To evaluate final irrigation protocols, groups 1, 3 and 5 were submitted to 3 protocols: (NI) No irrigation (n = 2); (CI) conventional irrigation (n = 4), and (EndoVac) irrigation (n = 4). The samples were scanned by microcomputed tomography and prepared for scanning electron microscopy evaluation. Quantitative data were evaluated using the parametric ANOVA test, with statistical significance level set at 5%, and qualitative data obtained were compared to establish the agreement between examiners through the Kappa test. It was observed that in the analysis of XP-endo Shaper protocols, the additional working time did not cause difference in any of parameters evaluated (p > 0.05) in relation to time recommended by manufacturer. Compared to Hyflex, XP-K showed highest mean volume increase (p < 0.05) and lowest percentage of untouched walls (p < 0.05). In the qualitative evaluation, final irrigation protocol with EndoVac provided the best cleaning results when associated with XP-K and with Hyflex. Thus, supplementary techniques are effective tools to enhance cleaning and to promote higher touch of walls during root canal preparation.

Microbiological and microstructural analysis of indwelling bladder catheters and urinary tract infection prevention / Análisis microbiológico y microestructural de sondas vesicales permanentes y prevención de infecciones del tracto urinario / Análise microbiológica e microestrutural dos cateteres vesicais de demora e prevenção de infecção do trato urinário

ABSTRACT Objective: To analyze the microbiological and microstructural part of indwelling urinary catheters and their association with urinary tract infection prevention. Method: This is a cross-sectional study, from June to December 2020, in which 42 indwelling urinary catheter tips and sterile urine samples were collected for analysis of crystals in optical microscopy and biofilms in scanning electron microscopy. Culture analysis and specification of the type of bacteria were performed. Results: It was found that 35.71% of the samples had mature biofilm adhered to the catheter tip. Biofilms of Proteus mirabilis, Enterococcus faecalis, Staphylococcus epidermidis, Enterococcus faecium and Enterobacter cloacae stood out. The presence of magnesium-ammonium-phosphate crystal was associated with the presence of urinary tract infection and with Proteus mirabilis. There was a significant association (p = 0.001) between the use of prophylactic antibiotics versus urine culture >105 CFU/mL. Conclusion: The analyzes contributed to clinical practice, as it reinforces the development of effective and monitored strategies on cultures and urinary tract infection prevention associated with indwelling urinary catheters.

RESUMEN Objetivo: Analizar la parte microbiológica y microestructural de los catéteres urinarios permanentes y su asociación con la prevención de la infección del tracto urinario. Método: Transversal, de junio a diciembre de 2020, en el que se recolectaron 42 puntas de sonda urinaria permanente y muestras de orina estéril para análisis de cristales en microscopía óptica y biopelículas en microscopía electrónica de barrido. Se realizaron análisis de cultivo y especificación del tipo de bacteria. Resultados: Se encontró que el 35,71% de las muestras presentaban biopelícula madura adherida a la punta del catéter. Se destacaron las biopelículas de Proteus mirabilis, Enterococcus faecalis, Staphylococcus epidermidis, Enterococcus faecium y Enterobacter cloacae. La presencia de cristales de fosfato de magnesio-amonio se asoció con la presencia de infección del tracto urinario y con Proteus mirabilis. Hubo una asociación significativa (p = 0,001) entre el uso de antibióticos profilácticos versus urocultivo >105 UFC/mL. Conclusión: Los análisis contribuyeron a la práctica clínica, ya que refuerzan el desarrollo de estrategias efectivas y monitoreadas sobre cultivos y prevención de la infección del tracto urinario asociada a los catéteres urinarios permanentes.

RESUMO Objetivo: Analisar a parte microbiológica e microestrutural dos cateteres vesicais de demora e sua associação com a prevenção de infecção do trato urinário. Método: Transversal, entre junho e dezembro de 2020, em que foram coletadas 42 pontas cateteres vesicais de demora e amostras de urina estéril para análise de cristais em microscopia óptica e de biofilmes em microscopia eletrônica de varredura. Fez-se analise de cultura e especificação do tipo de bactérias. Resultados: Verificou-se que 35,71% das amostras apresentaram o biofilme maduro aderido à ponta do cateter. Destacaram-se biofilmes de Proteus mirabilis, Enterococcus faecalis, Staphylococcus epidermidis, Enterococcus faecium e Enterobacter cloacae. A presença do cristal magnésio-amônio-fosfato foi associada à presença de infecção do trato urinário e ao Proteus mirabilis. Verificou-se associação significativa (p = 0,001) entre o uso de antibiótico profilático versus a urocultura >105 UFC/mL. Conclusão: As análises contribuíram para a prática clínica, pois reforçam a elaboração de estratégias efetivas e monitoradas sobre culturas e prevenção de infecção do trato urinário associada ao cateter vesical de demora.

Ultrastructural aspects of the skin in lipoid proteinosis (Urbach-Wiethe disease)

Abstract Lipoid proteinosis is a rare autosomal recessive disease, characterized by hyaline deposits of PAS-positive material in tissues due to mutations in the ECM1 gene. This study evaluated the ultrastructure of the skin of a 6-year-old child affected by this condition. The light microscopy identified PAS-positive hyaline deposits, which were more intense in the papillary dermis. Scanning electron microscopy of the dermis showed a compact papillary dermis and fibrillar deposits in the middle dermis. Transmission electron microscopy clearly showed the deposition of fibrillar material in the dermis, forming clusters adherent to elastic fibers, between the collagen bundles and the collagen fibers, and also filling up the cytoplasm of dermal fibroblasts.

Marginal misfit of heat-pressed milled wax-pattern and CAD/CAM crowns and its effect on stress distribution in implant-supported rehabilitations

Aim: To compare the marginal fit of lithium disilicate CAD/CAM crowns and heat-pressed crowns fabricated using milled wax patterns, and evaluate its effect on stress distribution in implantsupported rehabilitation. Methods: A CAD model of a mandibular first molar was designed, and 16 lithium disilicate crowns (8/group) were obtained. The crown-prosthetic abutment set was evaluated in a scanning electron microscopy. The mean misfit for each group was recorded and evaluated using Student's t-test. For in silico analysis, a virtual cement thickness was designed for the two misfit values found previously, and the CAD model was assembled on an implant-abutment set. A load of 100 N was applied at 30° on the central fossa, and the equivalent stress was calculated for the crown, titanium components, bone, and resin cement layer. Results: The CAD/CAM group presented a significantly (p=0.0068) higher misfit (64.99±18.73 µm) than the heat-pressed group (37.64±15.66 µm). In silico results showed that the heat-pressed group presented a decrease in stress concentration of 61% in the crown and 21% in the cement. In addition, a decrease of 14.5% and an increase of 7.8% in the stress for the prosthetic abutment and implant, respectively, was recorded. For the cortical and cancellous bone, a slight increase in stress occurred with an increase in the cement layer thickness of 5.9% and 5.7%, respectively. Conclusion: The milling of wax patterns for subsequent inclusion and obtaining heat-pressed crowns is an option to obtain restorations with an excellent marginal fit and better stress distribution throughout the implant-abutment set

Ultrastructural aspects of the skin in lipoid proteinosis (Urbach-Wiethe disease).

Lipoid proteinosis is a rare autosomal recessive disease, characterized by hyaline deposits of PAS-positive material in tissues due to mutations in the ECM1 gene. This study evaluated the ultrastructure of the skin of a 6-year-old child affected by this condition. The light microscopy identified PAS-positive hyaline deposits, which were more intense in the papillary dermis. Scanning electron microscopy of the dermis showed a compact papillary dermis and fibrillar deposits in the middle dermis. Transmission electron microscopy clearly showed the deposition of fibrillar material in the dermis, forming clusters adherent to elastic fibers, between the collagen bundles and the collagen fibers, and also filling up the cytoplasm of dermal fibroblasts.

Effect of various single file systems on microcrack formation in root canals: Scanning electron microscope study.

BACKGROUND: The aim of this study was to compare dentinal crack formation in root canal walls following 3 single file systems with continuous rotation under a scanning electron microscope (SEM). MATERIALS AND METHODS: In this SEM study, seventy mandibular premolars were randomly divided into 5 groups. 3 experimental groups (n = 20) and 2 control groups (n = 5) as follows: Group I: Neolix NiTi file system, Group II: OneShape systems, Group III: OneCurve file system, positive control: conventional Hand File system, negative control: unprepared. After root canal preparations, the roots were sectioned at 3, 6, and 9 mm from the apex with water irrigation. The sections were inspected in all directions under SEM at × 100 magnification to determine the presence of cracks. The Chi-square test was used to analyze the data. There is a statistically significant difference in the crack formation between the apical third (P = 0.012) and coronal third (P = 0.002) when comparing all the 5 groups. No significant difference is found in the middle third (P = 0.46). P < 0.05 is considered statistically significant. RESULTS: Maximum cracks in the apical third were seen with One Shape file 11 (55%) and in the coronal third with Neolix NiTi 14 (70%). There is a statistically significant difference in the crack formation only in OneCurve when comparing the apical, middle, and coronal third for the individual group (P = 0.042). CONCLUSION: There was a significant difference in crack formation in apical and coronal third. OneCurve caused the least incidence of cracks when compared to other file systems. OneCurve file system can be a choice for canal preparation over Neolix Niti and OneShape.

Transmission and scanning electron microscopy of cutis rhomboidalis

Abstract Cutis rhomboidalis nuchae was assessed in a 65-year-old patient. Optical microscopy showed basophilic agglomerations in the reticular dermis with decreased elastic fibers. Trans- mission electron microscopy showed elongated, curved and fragmented structures, and in their interior the presence of electron-dense lumps was reduced and irregular, similar to modified elastic fibers, whereas the collagen fibers had a normal aspect. Scanning electron microscopy showed deposits between the bundles of collagen, resembling pebbles or stones. These findings demonstrate that, at one stage of the disease, the collagen remains normal and the alterations are seen in the elastic tissue.

Transmission and scanning electron microscopy of cutis rhomboidalis.

Cutis rhomboidalis nuchae was assessed in a 65-year-old patient. Optical microscopy showed basophilic agglomerations in the reticular dermis with decreased elastic fibers. Transmission electron microscopy showed elongated, curved and fragmented structures, and in their interior the presence of electron-dense lumps was reduced and irregular, similar to modified elastic fibers, whereas the collagen fibers had a normal aspect. Scanning electron microscopy showed deposits between the bundles of collagen, resembling pebbles or stones. These findings demonstrate that, at one stage of the disease, the collagen remains normal and the alterations are seen in the elastic tissue.