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23 result(s) for "Spin-Neto, Rubens"
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Effect of data binning and frame averaging for micro-CT image acquisition on the morphometric outcome of bone repair assessment
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.
Exploring Dental Anatomy: An Ex Vivo Comparative Study Between Photon‐Counting Detector CT and Cone‐Beam CT
Objectives The aim of this ex vivo study was to assess the performance of photon‐counting detector computed tomography (PCD‐CT) compared with cone‐beam computed tomography (CBCT) at equivalent radiation doses for detecting and evaluating mandibular and dental anatomical structures in porcine cadavers. Material and Methods This intermodal comparative study evaluated imaging protocols at three radiation dose levels (high: 360 μSv, standard: 145 μSv, low: 20 μSv) in six porcine cadaver heads, analyzing 12 CBCT and 18 PCD‐CT volumes. Two blinded observers assessed image quality, artifact susceptibility, and diagnostic interpretability using a 5‐point Likert scale (5 = highest, 1 = lowest). Statistical analysis included descriptive statistics and interobserver reliability, assessed by weighted kappa (κ) analysis. Results PCD‐CT either matched or outperformed CBCT at standard‐ and low‐dose protocols, demonstrating superior anatomy coverage, density, contrast, and less artifact susceptibility. High‐ and standard‐dose protocols achieved perfect scores 5 (SD = 0). At low‐dose levels, PCD‐CT showed slightly lower scores but still outperformed CBCT. PCD‐CT showed minimal artifacts, with no significant artifacts in high and standard doses. Inter‐ and intra‐reader reliability was higher for PCD‐CT (κ: 0.694–1; p < 0.001) compared to CBCT (0.55–0.916; p < 0.001), with the difference being largest at low doses. Conclusion PCD‐CT outperforms CBCT in diagnostic interpretability and artifact reduction across various radiation dose levels, offering a promising alternative for dentomaxillofacial imaging that aligns with the ALADAIP principle.
Strontium enhances proliferation and osteogenic behavior of bone marrow stromal cells of mesenchymal and ectomesenchymal origins in vitro
Obejective To investigate the effect of increasing Strontium (Sr) concentrations on the growth and osteogenic behavior of human bone marrow stromal cells (BMSCs) from mesenchymal (i.e., fibula) and ectomesenchymal (i.e., mandible) embryonic origins. Materials and methods Fibula and mandible BMSCs were cultured in media without (Ctrl) or with Sr in four diverse concentrations: Sr1, 11.3 × 10−3 mg/L, human seric physiological level; Sr2, 13 mg/L, human seric level after strontium ranelate treatment; Sr3, 130 mg/L, and Sr4, 360 mg/L. Proliferation rate (1, 3, and 7 days), osteogenic behavior (alkaline phosphatase [ALP] activity, 7 and 14 days; expression of osteogenic genes (ALP, osteopontin, and osteocalcin at 7, 14, and 21 days), and formation of mineralized nodules (14 and 21 days) of the BMSCs were assessed. Data was compared group‐ and period‐wise using analysis of variance tests. Results Fibula and mandible BMSCs cultured with Sr4 showed increased proliferation rate, and osteocalcin and osteopontin gene expression together with more evident formation of mineralized nodules, compared all other Sr concentrations. For both cell populations, Sr4 led to lower ALP activity, and ALP gene expression, compared with the other Sr concentrations. Conclusion BMSCs from mesenchymal (i.e., fibula) and ectomesenchymal (i.e., mandible) embryonic origins showed increased cellular proliferation and osteogenic behavior when cultured with Sr4, in vitro.
Evaluating the effect of rapamycin treatment in Alzheimer’s disease and aging using in vivo imaging: the ERAP phase IIa clinical study protocol
Background Rapamycin is an inhibitor of the mechanistic target of rapamycin (mTOR) protein kinase, and preclinical data demonstrate that it is a promising candidate for a general gero- and neuroprotective treatment in humans. Results from mouse models of Alzheimer’s disease have shown beneficial effects of rapamycin, including preventing or reversing cognitive deficits, reducing amyloid oligomers and tauopathies and normalizing synaptic plasticity and cerebral glucose uptake. The “Evaluating Rapamycin Treatment in Alzheimer’s Disease using Positron Emission Tomography” (ERAP) trial aims to test if these results translate to humans through evaluating the change in cerebral glucose uptake following six months of rapamycin treatment in participants with early-stage Alzheimer’s disease. Methods ERAP is a six-month-long, single-arm, open-label, phase IIa biomarker-driven study evaluating if the drug rapamycin can be repurposed to treat Alzheimer’s disease. Fifteen patients will be included and treated with a weekly dose of 7 mg rapamycin for six months. The primary endpoint will be change in cerebral glucose uptake, measured using [ 18 F]FDG positron emission tomography. Secondary endpoints include changes in cognitive measures, markers in cerebrospinal fluid as well as cerebral blood flow measured using magnetic resonance imaging. As exploratory outcomes, the study will assess change in multiple age-related pathological processes, such as periodontal inflammation, retinal degeneration, bone mineral density loss, atherosclerosis and decreased cardiac function. Discussion The ERAP study is a clinical trial using in vivo imaging biomarkers to assess the repurposing of rapamycin for the treatment of Alzheimer’s disease. If successful, the study would provide a strong rationale for large-scale evaluation of mTOR-inhibitors as a potential disease-modifying treatment in Alzheimer’s disease. Trial registration ClinicalTrials.gov ID NCT06022068, date of registration 2023–08-30.
Dental-dedicated magnetic resonance imaging in the follow-up of lower third molar removal
The objective is to present a dental-dedicated magnetic resonance imaging (ddMRI)-based follow-up of inferior third molar removal over 12 months. A 30-year-old female presented with recurrent pain and bleeding from her lower right third molar. With adding diagnostic information from a panoramic image, the tooth was referred for removal. The patient underwent ddMRI using a dental coil with a proton density (PD) weighed turbo spin echo (TSE) sequence and a PD-TSE-STIR with fat suppression to highlight possible inflammatory processes. The scans were performed pre-operatively, immediately post-operatively, and in a rigorous follow-up (weekly basis for the first 6 weeks, bi-weekly from 7 to 12 weeks, and once at 6 and 12 months post-operatively). Using ImageJ software, circular ROIs were selected in the extraction alveolus coronary, middle, and apical regions. Mean grey values (MGVs) and standard deviation (SD) were obtained. A trend of decreasing MGVs in the PD (TSE) pulse sequence was observed over time, irrespective of the root third. Considering the PD-STIR (TSE), no trend was observed. ddMRI is feasible in the follow-up assessment of inferior third molar removal. Further clinical trials with larger samples are needed to define the usability of follow-up with ddMRI, considering a potential added diagnostic value.
Effect of osseodensification on the increase in ridge thickness and the prevention of buccal peri-implant defects: an in vitro randomized split mouth pilot study
Background Implant installation with conventional drilling can create buccal bone defects in areas of limited ridge thickness. Implant installation with osseodensification may aid in preventing buccal bone defects in these situations. This in vitro pilot study evaluated the impact of osseodensification on the increase in alveolar ridge thickness and the prevention of buccal peri-implant defects. Methods Ten fresh pig mandibles with limited bone thickness were selected for use in an experimental randomized split mouth pilot study. Two site-preparation protocols were used: conventional drilling with cutting burs (CTL, n = 10) and osseodensification with Densah® burs (OD, n = 10). After implant bed preparation, 20 implants (4.5 × 10 mm) were placed in the prepared sites and the insertion torque was recorded. Clinical and photographic analysis evaluated ridge thickness and the extent (height, width, and area) of bone defects in the buccal and lingual bone walls following implant placement. Three-dimensional measurements were performed using STL files to analyze the increase in buccal ridge thickness following site preparation and implant placement. The height of the buccal bone defect was considered as the primary outcome of this study. Defect width, area, implant insertion torque, and linear buccal ridge increase after implant site preparation and installation were also assessed. Non-parametric evaluations were carried out with the Mann–Whitney test to verify intergroup differences. Results There was no statistically significant difference between groups in the baseline ridge thickness. OD presented a significantly higher insertion torque, associated with reduced buccal and lingual bone defect width, in comparison to CTL. Conclusions The increase in buccal ridge thickness after site preparation and implant placement was significantly higher in OD compared to CTL. Osseodensification increased the ridge thickness through expansion and reduced buccal bone defects after implant installation.
Nicodemo’s method for age estimation of children, adolescents and young adults: a systematic review focusing on accuracy
Background Different methods of age estimation have been proposed and consolidated in the literature. Among them, the Nicodemo, Moraes & Medici Filho Method (1974) (“Nicodemo’s method”—NMM) was developed. Main body This systematic review aimed to assess the accuracy of the NMM method in estimating the age of children, adolescents, and young adults. Observational studies that used the NMM method to estimate the age of healthy individuals, via panoramic radiographs, were included. No restrictions on language or year of publication were applied. The electronic search was conducted in major scientific platforms (Embase, LILACS, BBO, CUMED, MedLine via PubMed and Scopus) and grey literature (EASY and Google Scholar). The risk of bias of the studies was assessed using the JBI checklist. The search identified fifteen eligible studies ( n  = 6505 individuals aged 3–25 years). The studies were conducted between 1999 and 2024 and had a low to moderate risk of bias. Most of the studies were conducted in Brazil ( n  = 13). All teeth were included. The authors applied the NMM method based on the method's accuracy rate or by averaging the estimated and chronological ages. The method's accuracy rate varied between 16.8% and 82.9%. The younger age groups (between 7.5 and 10 years) showed a higher percentage of accuracy. Conclusion The NMM method was not accurate in estimating the age of individuals over 14 years old, and underestimated age in most studies. The application of the method should be performed with caution, and the association with other age estimation methods is recommended.
Oral Health and Brain Injury: Causal or Casual Relation?
Background: To systematically review the current literature investigating the association between oral health and acquired brain injury. Methods: A structured search strategy was applied to PubMed, Embase, Web of Science, and CENTRAL electronic databases until March 2017 by 2 independent reviewers. The preferred reporting items for systematic review and meta-analysis guidelines were used for systematic review. Results: Even though the objective was to assess the association between oral health and acquired brain injury, eligible studies focused solely on different forms of stroke and stroke subtypes. Stroke prediction was associated with various factors such as number of teeth, periodontal conditions (even after controlling for confounding factors), clinical attachment loss, antibody levels to Aggregatibacter actinomycetemcomitans and Prevotella intermedia. The literature showed no consensus on the possible association between gingivitis and stroke. Patients with stroke generally had poorer oral hygiene practices and oral health. Dental prophylaxis and professional intervention reduced the incidence of stroke. Conclusions: Overall, oral health and stroke were related. Periodontitis and tooth loss were independently associated with stroke. However, prevention and timely intervention may reduce the risk of stroke. Stroke was the main cerebral lesion studied in the literature, with almost no publications on other brain lesions.
Systemic administration of strontium ranelate to enhance the osseointegration of implants: systematic review of animal studies
The literature states that Strontium (Sr) is able to simultaneously stimulate bone formation and suppress bone resorption. Recent animal studies suggest that the systemic administration of Sr, in the form of strontium ranelate (SRAN), would enhance the osseointegration of implants. The purpose of the present study was to undertake a systematic review on animal studies evaluating the systemic administration of Sr to enhance the osseointegration of titanium implants and the remodeling of bone grafts. The MEDLINE (PubMed) and Scopus bibliographic databases were searched from 1950 to October 2017 for reports on the use of systemic and non-radioactive Sr to enhance the osseointegration of titanium implants and the remodeling of bone grafts in animals. The search strategy was restricted to English language publications using the combined terms: “strontium” and “implant or graft or biomaterial or bone substitute”. Five studies were included, all related to the systemic administration of Sr in the form SRAN, and its effects on osseointegration of titanium implants. No studies on the use of SRAN-based therapy to enhance the remodeling of bone grafts were found. The studies differed notably with respect to the study population (healthy female rats, healthy male rats, and female rats with induced osteoporosis) and SRAN dose (ranging from 500 to 1000 mg/kg/day). Results were diverse, but a tendency suggesting positive influence of systemic SRAN administration on the osseointegration of titanium implants was observed. No major side-effects due to strontium administration were reported. Systemic Sr administration, in the form of SRAN, seems to enhance peri-implant bone quality and implant osseointegration in animals, however, at a moderate extent. Further studies, evaluating both the effects of this drug on implant osseointegration and the risk/benefit of its use, are needed to provide a rationale of this therapeutic approach.
Artificial Intelligence for Detecting Cephalometric Landmarks: A Systematic Review and Meta-analysis
Using computer vision through artificial intelligence (AI) is one of the main technological advances in dentistry. However, the existing literature on the practical application of AI for detecting cephalometric landmarks of orthodontic interest in digital images is heterogeneous, and there is no consensus regarding accuracy and precision. Thus, this review evaluated the use of artificial intelligence for detecting cephalometric landmarks in digital imaging examinations and compared it to manual annotation of landmarks. An electronic search was performed in nine databases to find studies that analyzed the detection of cephalometric landmarks in digital imaging examinations with AI and manual landmarking. Two reviewers selected the studies, extracted the data, and assessed the risk of bias using QUADAS-2. Random-effects meta-analyses determined the agreement and precision of AI compared to manual detection at a 95% confidence interval. The electronic search located 7410 studies, of which 40 were included. Only three studies presented a low risk of bias for all domains evaluated. The meta-analysis showed AI agreement rates of 79% (95% CI: 76–82%, I2 = 99%) and 90% (95% CI: 87–92%, I2 = 99%) for the thresholds of 2 and 3 mm, respectively, with a mean divergence of 2.05 (95% CI: 1.41–2.69, I2 = 10%) compared to manual landmarking. The menton cephalometric landmark showed the lowest divergence between both methods (SMD, 1.17; 95% CI, 0.82; 1.53; I2 = 0%). Based on very low certainty of evidence, the application of AI was promising for automatically detecting cephalometric landmarks, but further studies should focus on testing its strength and validity in different samples.