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Objective: This study aimed to evaluate the dose–response effects of ionizing radiation (IR) on alveolar bone repair and bone strength after tooth extraction. Materials and methods: A total of 32 male Wistar rats were used in the study, 28 animals were included in the final analysis, and n = 7 for each experimental group. Mandibular first molars were extracted. After 7 days, the animals were randomly divided into four groups according to single-dose irradiation: NIr, control group; Ir15, irradiated at 15 Gy; Ir20, irradiated at 20 Gy; and Ir30, irradiated at 30 Gy. The tooth extraction sites were subjected to micro-computed tomography (micro-CT), histological, histomorphometric, and biomechanical analyses 14 days after extraction. Data were analyzed using one-way ANOVA followed by Tukey's post hoc test (α = 0.05). Results: Micro-CT analysis revealed that IR led to lower values of bone volume (BV, in mm3) (0.68 ± 0.08, P < 0.001) and bone volume fraction, ratio of the segmented bone volume to the total volume of the region of interest (BV/TV, in %) (44.1 ± 8.3, P < 0.001) for the Ir30 group compared to the control group. A significantly lower amount of newly formed bone was observed in the Ir30 (P = 0.005) than in the Ir15 group. The histomorphometric results of quantification of bone matrix neoformation and the micro-CT were in agreement, demonstrating greater damage to the Ir30 group. IR30 cells showed a lower percentage of densely packed collagen than control cells. No significant differences were found in the biomechanical parameters. Conclusion: IR affects alveolar bone repair. A dose of 30 Gy reduced the bone healing process owing to a smaller amount of newly formed bone and a lower percentage of densely packed collagen. Therefore, a dose of 30 Gy can be used to successfully establish an animal model of an irradiated mandible that mimics the irradiated clinical conditions. Clinical relevance: Radiotherapy can lead to severe side effects and tooth extraction is a major risk factor. A proper understanding of the pathological mechanisms of radiation in alveolar bone repair requires the establishment of a suitable animal model of clinical conditions. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the effects of advanced platelet-rich fibrin (A-PRF +) on the healing of upper third molar post-extraction sockets. Methods: Sixteen patients who underwent extractions of the upper third molars (18 and 28) were included in this randomized split-mouth study. The alveoli on the test side were filled with A-PRF + , while the control side was maintained with blood clot. The side that received treatment was randomly defined. Alveolar bone regeneration was evaluated by CBCT scans to assess healing stage, bone density, and fractal analysis 1 week and 90 days post-extraction. Additionally, pain, edema, bleeding, and soft tissue alveolar repair were evaluated by clinical analyses 3, 7, 14, 30, and 90 days after the surgical procedure using a visual analog scale. Results: There were no clinical differences regarding treatments in any experimental period. In the tomographic evaluation, at 7 days, the alveoli treated with A-PRF + presented a suggestive sign of higher bone density than the control alveoli, which was not confirmed 90 days after the surgical procedure. Conclusion: Thus, the use of A-PRF + does not demonstrate a clinical advantage in the repair of post-extraction sockets of upper third molars. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the influence of the extraction socket (distal or lingual root) and the type of region of interest (ROI) definition (manual or predefined) on the assessment of alveolar repair following tooth extraction using micro-computed tomography (micro-CT). The software package used for scanning, reconstruction, reorientation, and analysis of images (NRecon®, DataViewer®, CT-Analyzer®) was acquired through Bruker < https://www.bruker.com >. The sample comprised the micro-CT volumes of seven Wistar rat mandibles, in which the right first molar was extracted. The reconstructed images were analyzed using the extraction sockets, i.e., the distal and intermediate lingual root and the method of ROI definition: manual (MA), central round (CR), and peripheral round (PR). The bone volume fraction (BV/TV) values obtained were analyzed by two-way ANOVA with Tukey's post hoc test (α = 5%). The distal extraction socket resulted in significantly lower BV/TV values than the intermediate lingual socket for MA (P = 0.001), CR (P < 0.001), and PR (P < 0.001). Regarding the ROI, when evaluating the distal extraction socket, the BV/TV was significantly higher (P < 0.001) for MA than for CR and PR, with a lower BV/TV for CR. However, no significant difference was observed for MA (P = 0.855), CR (P = 0.769), or PR (P = 0.453) in the intermediate lingual extraction socket. The bone neoformation outcome (BV/TV) for alveolar bone repair after tooth extraction is significantly influenced by the ROI and the extraction socket. Using the predefined method with a standardized ROI in the central region of the distal extraction socket resulted in the assessment of bone volume, demonstrating the most critical region of the bone neoformation process. [ABSTRACT FROM AUTHOR]

Despite the current advances in micro-CT analysis, the influence of some image acquisition parameters on the morphometric assessment outcome have not been fully elucidated. The aim of this study was to determine whether data binning and frame averaging affect the morphometric outcome of bone repair assessment using micro-CT. Four Wistar rats' tibiae with a surgically created bone defect were imaged with micro-CT six times each, frame averaging set to 1 and 2, and data binning set to 1, 2 and 4, for each of the averaging values. Two-way ANOVA followed by Bonferroni tests assessed the significance of frame averaging and data binning on a set of morphometric parameters assessed in the image volumes (p < 0.01). The effect of frame averaging was not significant for any of the assessed parameters. Increased data binning led to larger trabecular thickness. In contrast, smaller bone volume fraction and bone volume were found as data binning increased. Trabeculae number and trabecular separation were not influenced by any of the parameters. In conclusion, the morphometric outcome of bone repair assessment in micro-CT demonstrated dependency upon data binning, but not frame averaging. Therefore, image acquisition of small anatomical structures (e.g., rat trabeculae) should be performed without data binning. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the effect of ionizing radiation and cariogenic biofilm challenge using two continuous flow models, normal and reduced salivary flow, on the development of initial root-dentin caries lesions. Materials and methods: Microcosm biofilms were grown under two salivary flow rates (0.06 and 0.03 mL min−1) and exposed to 5% sucrose (3 × daily, 0.25 mL min−1, 6 min) dripped over non-irradiated and irradiated root-dentin blocks for up to 7 days. The vibration modes of root dentin, matrix/mineral (M/M), and carbonate/mineral (C/M) ratios were evaluated by FTIR. The mineral density was assessed by micro-CT. Results: With normal salivary flow, FTIR revealed an increase in the organic matrix (amide III) and a decrease in the mineral phase (ν4, ν2 PO43−, AII + ν2 CO32−, C/M) in caries lesions. Irradiated dentin exhibited a reduction in the mineral phase (ν1, ν3 PO43−, ν2 CO32−, C/M). Differences in mineral densities were not significant. With reduced salivary flow, FTIR also revealed increased organic matrix (amide III) for irradiated caries lesions and decrease in mineral phase (v4, v2 PO43−, v2 CO32−, and C/M) in caries lesions. ν1, ν3 PO43− precipitated on the surface of irradiated dentin and a lower mineral density was observed. Conclusions: Initial caries lesions differed between non-irradiated and irradiated dentin and between normal and reduced salivary flow rates. Significant mineral loss with exposure of the organic matrix and low mineral density were observed for irradiated dentin with a reduced salivary flow rate. Clinical relevance: Ionizing radiation associated with a reduced salivary flow rate enhanced the progression of root-dentin caries. [ABSTRACT FROM AUTHOR]

We report and discuss the surprising encounter of a dog naturally infected by Dracunculus sp. in Brazil, a brief clinical history of the animal and a procedure for removing the nematode. We also present details on the morphology of the fragments collected from the nematode and a phylogenetic comparison of the partial sequences of the mitochondrial 18S rRNA and cytochrome c oxidase subunit I (COI) genes, deposited with others in GenBank. The samples were an independent lineage forming a well-supported monophyletic assemblage with D. medinensis. We thus conclude that this species has not yet been sequenced or even described and will only be elucidated by more information because only two species of Dracunculus have been reported in Brazil, D. fuelleborni and D. brasiliensis. [ABSTRACT FROM AUTHOR]

Background: Several drugs are capable of promoting changes in bone metabolism. The aim of this study was to evaluate the effect of long-term low-dose aspirin (LDA) therapy on implant osseointegration. Methods: Male Wistar rats were divided into 4 groups (n = 8/group) according to oral gavage solution received prior (42 days) to the implant surgery on the tibia. The control group was treated with saline solution for 7 (CG-7) and 28 (CG-28) days. The use of low-dose aspirin was performed in AG groups (6.75 mg/kg of aspirin) for 7 (AG-7) and 28 (AG-28) days. After experimental periods, histomorphometric evaluation of bone-to-implant contact (BIC) and the bone area between threads (BABT) was performed. Results: Reduced BIC values were detected in AG-7 (62.8% ± 17.1) group compared to AG-28 (91.9% ± 5.4), CG-7 (82.7% ± 15.2), and CG-28 (89.9% ± 9.7). BABT evaluation revealed lower values in AG-7 (70.9% ± 15.2) compared to AG-28 (95.4% ± 3.7) and CG-28 (87.1% ± 10.2) groups. Conclusions: The treatment with low doses of aspirin promoted a discrete inhibitory effect in the early stages (7 days) of repair after implant placement, specifically in the bone deposition. However, these effects were not detected in the late stages (28 days), considering BIC and BABT parameters. [ABSTRACT FROM AUTHOR]

Objectives: Evaluate the effects of ionizing radiation on microarchitecture, the osteocyte lacunar network, and collagen maturity in a bone repair site. Materials and methods: Bone defects were created on tibias of 20 New Zealand rabbits. After 2 weeks, the animals were randomly divided into (n = 10) NoIr (nonirradiated group) and Ir (irradiated group). In the Ir, the animals received single-dose irradiation of 30 Gy on the tibia and were euthanized after 2 weeks. Bone microarchitecture parameters were analyzed by using micro-CT, and the osteocyte lacunar network, bone matrix, and collagen maturation by histomorphometric analysis. The data were analyzed using unpaired Student's t test (α = 0.05). Results: Trabecular thickness in Ir was lower than that in NoIr (P = 0.028). No difference was found for bone volume fraction and bone area. Lacunae filled with osteocytes were more numerous (P < 0.0001) in NoIr (2.6 ± 0.6) than in Ir (1.97 ± 0.53). Empty lacunae were more prevalent (P < 0.003) in Ir (0.14 ± 0.10) than in NoIr (0.1 ± 0.1). The mean osteocyte lacunae size was higher (P < 0.01) in Ir (15.4 ± 4.41) than in NoIr (12.7 ± 3.7). Picrosirius red analysis showed more (P < 0.05) mature collagen in NoIr (29.0 ± 5.3) than in Ir (23.4 ± 4.5). Immature collagen quantification revealed no difference between groups. Conclusions: Ionizing radiation compromised bone formation and an impairment in bone repair in irradiated woven bone was observed. Clinical relevance: Before radiotherapy, patients usually need surgical intervention, which may be better performed, if clinicians understand the repair process in irradiated bone, using novel approaches for treating these individuals. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the effects of radiotherapy on biomechanical, histomorphometric, and microstructural characteristics of bone, in diverse periods, compared with intact bone tissue. Materials and methods: Eighteen adult male New Zealand rabbits were treated with a single radiation dose of 30 Gy. The animals were randomly divided into six groups: NoIr, control group, no radiation, and five irradiated groups sacrificed after 24 h (Ir24h), 7 (Ir7d), 14 (Ir14d), 21 (Ir21d), and 28 (Ir28d) days. After these periods, the animals were sacrificed and their tibias (n = 6) evaluated using three-point bending test to calculate the ultimate force, work to failure, and bone stiffness. Dynamic indentation test was used to quantify Vickers hardness and elasticity modulus of bone tissue. Micro-CT was used to analyze the cortical volume (CtV), cortical thickness (CtTh), and porosity (Ct.Po). Histomorphometric assessment was based on the lacunarity of bone tissue. Data were analyzed using one-way ANOVA and Kruskal−Wallis tests followed by Tukey, Dunnet, and Dunn's post-tests (P < 0.05). Results: The ultimate force, work to failure, stiffness, elastic modulus, and Vickers hardness values of irradiated bone were significantly lower that non-irradiated bone. Irradiated bone showed significantly lower CtTh and CtV values and higher CtPo than non-irradiated bone. No significant difference was found for lacunarity between non-irradiated bone and irradiated bone. Conclusions: Ionizing radiation decreases normal anisotropy on microarchitecture of cortical bone, and increases bone fragility compared with non-irradiated bone. Further, these changes were seen after longer periods (e.g., 14 and 21 days), and not immediately after radiation therapy. Clinical relevance: The radiotherapy reduces bone mechanical properties and the normal structure of organic and inorganic bone matrix. For studying the protocols to protect the radiotherapy effect using rabbit model, the use of the sacrificing period between 14 and 21 days is recommended. [ABSTRACT FROM AUTHOR]

Previous studies showed infections of Hepatozoon caimani in wild populations of caimans in wide regions from Brazil; some of those demonstrated that trophic chain are linked to natural infections through paratenic hosts or by the direct ingestion of vectors. These studies life cycle of H. caimani contributed inestimably to the knowledge of transmission routes, yet but lack enhancement tools for better detail of parasite. This study reports the forms in the blood and tissues, and also partial molecular characterization of the H. caimani following part of the 18S rRNA region. In the southern Pantanal, there were sampling 39 adult caimans ( Caiman yacare), where 31 (79.5%) were parasitized by H. caimani. Free gametocytes had an average intensity of 19.6% and intraerythrocytic forms 7.42%, in the blood smears. In stained smears of the liver and lungs of naturally infected caimans which were examined, monozoic and dizoic cysts were found in these tissues, generally next to the vessels. In the histopathology, meronts were observed in the wall of vessels from liver and kidney ducts. Blood samples were forwarded to PCR process and produced amplicons with about 600 and 900 bp, respectively, for the primers HEPF300/HEP900 and HEMO1/HEMO2. This was the first report of molecular confirmation of Hepatozoon in populations of naturally infected caimans of morphological detail of the gametocytes in scanning electron microscopy and histology of merogony in livers and kidneys of C. yacare. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the effect of roughness parameters and hydrophobicity of restorative material used to restore non-carious cervical lesions on the biofilm formation. Four restorative materials were investigated: conventional glass ionomer cement (KF, Ketac Fill Plus, 3M ESPE), resin-modified glass ionomer cement (VT, Vitremer, 3M ESPE), nanofilled resin-modified glass ionomer cement (KN, Ketac Nano, 3M ESPE), and nanofilled resin composite (FZ, Filtek Z350 XT, 3M ESPE). Forty disk specimens were prepared from each material, dived in four groups. Five samples were used for topography parameters analysis using a 3D profilometry. The amplitude parameters (Sa and Sq), spatial parameter (Sds), and hybrid parameter (Ssc) were extracted in area using cut-off of 0.25 mm. Hydrophobicity was determined by the contact angle measurement of deionized water on the surface. The biofilm collected from a 24-year-old subject was grown on modified brain-heart infusion agar under aerobic conditions at 37 °C for 24 h. Each test disk was immersed in 200 µL of biofilm suspension ( n = 10) and incubated for 24 h at 37 °C. Biofilm was evaluated after 24 h formation on each disk after stained with 1 % fluorescein using confocal laser-scanning microscopy. Data were analyzed using one-way ANOVA and Tukey test ( α = 0.05), Pearson correlation was used to compare topography parameters with biofilm formation. Significant differences were found in related amplitude parameters (Sa and Sq, FZ = KN > VT > KF). KN presented the highest hydrophobicity. FZ and KN presented the lowest thickness and biovolume of biofilm when compared with VT and KF. All topography parameters were significantly correlated with biofilm formation. FZ and KN, material with nanoparticles presented better performance-related topography parameters and biofilm formation. Clinical relevance: The incorporation of nanotechnology into restorative materials promotes better surface topography with lower biofilm formation. [ABSTRACT FROM AUTHOR]

The susceptibility of two fish and four mosquito species to the Caiman yacare haemoparasite Hepatozoon caimani was experimentally investigated. Mosquitoes belonging to four species ( Aedes fluviatilis, Aedes albopictus, Aedes aegypti and Culex quinquefasciatus) were blood-fed on two naturally infected C. yacare from the Central-West Region of Brazil that exhibited distinct levels of parasitaemia: caimans A (11.05 %) and B (1.25 %). None of the engorged A. fluviatilis, A. albopictus or A. aegypti mosquitoes fed on caiman A survived for the duration of the sporogonic cycle; the great majority of the engorged mosquitoes died within 48 h of the blood meal. All A. aegypti fed on caiman B were negative, whereas 91.3 % of dissected C. quinquefasciatus fed on the same caiman contained oocysts. Characid fish- Metynnis sp. and Astyanax sp.-were individually fed with C. quinquefasciatus females previously engorged (21-23 days) on caiman B. No parasite was found in the Astyanax fish. By contrast, 100 % of the Metynnis fish depicted numerous cysts harbouring cystozoites identical to those of H. caimani, even more than 8 months after the ingestion of the infected mosquitoes. The cysts were located near the veins of the liver and, in some cases, close to the tunica intima of these vessels. No inflammatory reaction was observed. Gametocytes were observed in the blood smears of juvenile caimans that had ingested infected fish 9-12 weeks earlier. The potential role of fish as paratenic vertebrate hosts of H. caimani in nature is discussed. [ABSTRACT FROM AUTHOR]

Prevalence of Hepatozoon caimani has been reported in 76% of caimans Caiman yacare from the Pantanal region. Culex ( Melanoconion) spp. mosquitoes were recently identified as natural vectors of this parasite. However, culicids are not typically eaten by crocodilians, suggesting that the main transmission route is through ingestion of insectivorous vertebrates, such as anurans. The susceptibility of wild frogs Leptodactylus chaquensis, Leptodactylus podicipinus and Scinax nasicus to infection by H. caimani was verified. Wild-caught anurans were force fed with sporulated oocysts from laboratory-bred Culex ( Melanoconion) mosquitoes. Frogs were killed 30 days postinfection, and their internal organs were fed to caimans C. yacare and Caiman latirostris. Cystozoites were identified in fresh liver impression smears of L. chaquensis. C. yacare fed on anuran organ presented gametocytes in peripheral blood circulation between 74 and 80 days postinoculation (dpi). Gametocytes were also verified in C. latirostris fed on the internal organs of L. podicipinus and S. nasicus between 60-70 and 69-75 dpi, respectively. Since frogs used in experiment are sympatric with C. yacare and C. latirostris and may occur in the diet of these caimans, the results suggest these amphibians are paratenic hosts in the natural transmission cycle of H. caimani in Pantanal. [ABSTRACT FROM AUTHOR]