Surface imaging of the filamentous fungus Penicillium simplicissimum growing in a solid-state fermentation system.

A comparative study on the lipase-producing fungus Penicillium simplissicimum, grown on a tray type solid-state fermentation (SSF) bioreactor, was performed using stereoscopy, focus Z-stacking stereoscopic images, field emission scanning electron microscopy (FE-SEM) and environmental scanning electron microscopy (ESEM) to better characterize the morphology of filamentous fungi in SSF and their distribution over the solid matrix. The imaging of live fungal samples using a stereomicroscope with focus Z-stacking showed differences in colonization between a static SSF and an intermittent agitated SSF. A comparison of the stereomicroscopy, hi-vacuum and environmental scanning electron microscopy results obtained using different protocols for sample processing showed that fixation with osmium tetroxide vapor and subsequent hydrated imaging is the best combination of sample preparation and imaging conditions for keeping the arrangement of the aerial hyphae and conidia morphology closer to the natural state. These combined methodologies can be applied in the SSF of fungal growth to characterize the formation of conidiophores over time, the conidia morphology and the spatial organization after their release from conidiophores. Mycelium colonization over the matrix, which is an important characteristic related to the production of different biotechnological products, could be observed and provide more knowledge about fungal physiology behavior during SSF.

Effectiveness of hand and Mtwo TM Instruments in preparing oval-shaped root canals: in vitro study

Objective: This study evaluated through stereomicroscopy the effectiveness of hand and rotary instrumentation techniques, either isolated or combined, in the preparation of oval-shaped root canals. Materials and method: Thirty single-rooted human mandibular incisors were selected. After endodontic access and coronal preflaring, teeth were mounted in a modified Bramante muffle and then sectioned transversely at 3 and 6 mm from the root apex. Images of each section were made under a stereomicroscope at 30× magnification. Teeth were reassembled in the muffle and divided into three groups (n=10) according to the root canal preparation technique: GI - rotary preparation with Mtwo™ basic sequence (10/.04; 15/.05; 20/.06; 25/.06), followed by Mtwo™ complementary instruments (30/.05; 35/.04; 40/.04); GII - rotary preparation with Mtwo™ basic sequence, complemented by hand instruments (#30, #35 and #40); GIII - hand instrumentation using the conventional technique (#10 to #40). All instruments were used in brushing motion. The muffles were separated again so that new images of each section could be obtained. The following parameters were evaluated in pre- and postoperative images: root canal area; perimeter; mesiodistal (MD) and buccolingual (BL) diameters; and mesial (M) and distal (D) wall thickness. Next, the values measured in post- and preoperative images were subtracted for comparison of experimental groups. Data were analyzed using the Kruskal-Wallis test (α=0.05). Results: No significant difference between groups was observed for all parameters. Conclusion: There was no difference among hand, rotary, or combined instrumentation; all techniques were able to increase root canal area, perimeter, and diameter in MD and BL directions. Moreover, the amount of dentin wear on proximal root canal walls was similar for all tested groups. Keywords: Endodontics. Microscopy. Root canal preparation. Root canal therapy. Stereomicroscopy.

3D scanning electron microscopy applied to surface characterization of fluorosed dental enamel.

The enamel surfaces of fluorotic teeth were studied by scanning electron stereomicroscopy. Different whitening treatments were applied to 25 pieces to remove stains caused by fluorosis and their surfaces were characterized by stereomicroscopy in order to obtain functional and amplitude parameters. The topographic features resulting for each treatment were determined through these parameters. The results obtained show that the 3D reconstruction achieved from the SEM stereo pairs is a valuable potential alternative for the surface characterization of this kind of samples.

A stereomicroscopic in- vitro study to investigate the root canal morphology of mandibular third molars using clearing technique

AIM: To analyse the root canal morphology of mandibular third molars using clearing technique. MATERIAL AND METHODS: Ninety permanent extracted mandibular third molar teeth were collected based on inclusion and exclusion criteria. Teeth were then decalcified and were made transparent Methylene Blue Dye was injected to color the pulp space. These teeth were then observed under sterio Microscope and root canal systems were identified according to Vertucci's Classification. RESULTS: The most common anatomical morphology found was having two roots. Overall type I Vertucci's configuration was the most common pattern of canals. Other canal patterns that were found included type II, III, IV and V. In this study no canal of type VI, VII or VIII were found. CONCLUSION: The morphological variations in root patterns and canal configuration of mandibular third molar should be given consideration for successful endodontic treatment.

Characteristics of secondary caries lesion around composite resin restorations / Características da cárie secundária adjacente a restaurações de resinacomposta

Objetivo: O objetivo deste estudo foi analisar as características de cárie secundária e sua relação com a presença de restaurações com defeitos marginais como gap, degrau negativa (NL, a falta de material restaurador) e degrau positiva (PL, saliência). Materiais e Métodos: Oitenta superfícies proximais de restaurações de resina classe II foram fotografados e analisados utilizando um microscópio estereoscópico (X40). Foi registrada a presença de cáries secundárias externas, gaps, NL, PL e após a remoção de restaurações, a presença de lesão interna. Todos os exames foram realizados em 10 pontos bem definidos. Resultados: A prevalência de cárie secundária e gap foram associados com margem gengival. As restaurações com defeitos marginais (NL e PL) não foram associados a qualquer local específico (vestibular, lingual ou gengival). Observou-se uma relação entre esses defeitos com a prevalência de cárie secundária. A presença da lesão interna foi associada com lesão externa. Embora, em 141 pontos foi observada lesão interna, sem a presença de lesão externa. A maioria destas lesões mostraram envolvimento de esmalte interno. Apenas 8 por cento tinham desmineralização restrito a dentina, que poderia sugerir cárie residuais.

Objective: The aim of this study was to analyze the features of secondary caries and their relationship with the presence of restorations marginal defects as gap, negative ledge (NL, lack of restorative material) and positive ledge (PL, overhang). Materials and methods: Eighty proximal surfaces of Class II resin restorations were photographed and analyzed using a stereomicroscope (X40). It was recorded the presence of external secondary caries, gaps, NL, PL and after the restorations removal, the presence of internal lesion. All the exams were done in 10 welldefined points. Results: The prevalence of secondary caries and gap were associated with gingival margin. The restorations marginal defects (NL and PL) were not associated with any specific location (buccal, lingual or gingival). It was observed a relationship between these defects with secondary caries prevalence (gap: p= 0.004; NL and PL: p= 0.017). This association could be explained by the biofilm accumulation usually observed in the interface tooth surface/ restoration marginal defects. The presence of internal lesion was associated with external lesion. Although, in 141 points was observed internal lesion without the presence of external lesion. The majority of these lesions showed internal enamel involvement. Only 8 percent had demineralization restricted to dentine, which could suggest residual caries. Conclusion: The results of this study showed that secondary caries lesion frequently began externally on the interface tooth/restoration, where diagnose, control and arrestment of the lesions is possible.