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BioMed Research International 2022Recently, dentists can utilize three-dimensional printing technology in fabricating dental restoration. However, to date, there is a lack of evidence regarding the...
BACKGROUND
Recently, dentists can utilize three-dimensional printing technology in fabricating dental restoration. However, to date, there is a lack of evidence regarding the effect of printing layer thicknesses and postprinting on the mechanical properties of the 3D-printed temporary restorations with the additive manufacturing technique. So, this study evaluated the mechanical properties of a 3D-printed dental resin material with different printing layer thicknesses and postprinting methods.
METHODS
210 specimens of a temporary crown material (A2 EVERES TEMPORARY, SISMA, Italy) were 3D-printed with different printing layer thicknesses (25, 50, and 100 m). Then, specimens were 3D-printed using DLP technology (EVERES ZERO, DLP 3D printer, SISMA, Italy) which received seven different treatment conditions after printing: water storage for 24 h or 1 month, light curing or heat curing for 5 or 15 minutes, and control. Flexural properties were evaluated using a three-point bending test on a universal testing machine (ISO standard 4049). The Vickers hardness test was used to evaluate the microhardness of the material system. The degree of conversion was measured using an FT-IR ATR spectrophotometer. Statistical analysis was performed using two-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) test ( ≤ 0.05).
RESULTS
The 100 m printing layer thickness had the highest flexural strength among the other thickness groups. As a combined effect printing thickness and postprinting conditions, the 100 m with the dry storage group has the highest flexural strength among the tested groups (94.60 MPa). Thus, the group with 100 m thickness that was heat cured for 5 minutes (HC 5 min 100 m) has the highest VHN value (VHN = 17.95). Also, the highest mean DC% was reported by 50 m layer thickness (42.84%).
CONCLUSIONS
The thickness of the 100 m printing layer had the highest flexural strength compared to the 25 m and 50 m groups. Also, the postprinting treatment conditions influenced the flexural strength and hardness of the 3D-printed resin material.
Topics: Flexural Strength; Hardness; Humans; Materials Testing; Printing, Three-Dimensional; Resins, Plant; Spectroscopy, Fourier Transform Infrared; Surface Properties
PubMed: 35237691
DOI: 10.1155/2022/8353137 -
Scientific Reports Jan 2021Current descriptions of retinal thickness across normal age cohorts are mostly limited to global analyses, thus overlooking spatial variation across the retina and...
Current descriptions of retinal thickness across normal age cohorts are mostly limited to global analyses, thus overlooking spatial variation across the retina and limiting spatial analyses of retinal and optic nerve disease. This retrospective cross-sectional study uses location-specific cluster analysis of 8 × 8 macular average grid-wise thicknesses to quantify topographical patterns and rates of normal, age-related changes in all individual retinal layers of 253 eyes of 253 participants across various age cohorts (n = 23-69 eyes per decade). Most retinal layers had concentric spatial cluster patterns except the retinal nerve fibre layer (RNFL) which displayed a nasal, asymmetric radial pattern. Age-related thickness decline mostly occurred after the late 4th decade, described by quadratic regression models. The ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), and outer nuclear layer + Henle's fibre layer (ONL) were significantly associated with age (p < 0.0001 to < 0.05), demonstrating similar rates of thickness decline (mean pooled slope = - 0.07 µm/year), while the IS/OS had lesser mean pooled thickness slopes for all clusters (- 0.04 µm/year). The RNFL, OPL, and RPE exhibited no significant age-related thickness change, and the RNFL were significantly associated with sex. Analysis using spatial clusters compared to the ETDRS sectors revealed more extensive spatial definition and less variability in the former method. These spatially defined, clustered normative data and age-correction functions provide an accessible method of retinal thickness analysis with more spatial detail and less variability than the ETDRS sectors, potentially aiding the diagnosis and monitoring of retinal and optic nerve disease.
Topics: Adult; Aged; Aging; Cluster Analysis; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Optic Nerve Diseases; Regression Analysis; Retina; Retinal Diseases; Retrospective Studies; Sex Characteristics; Tomography, Optical Coherence; Young Adult
PubMed: 33436715
DOI: 10.1038/s41598-020-79424-6 -
International Journal of Ophthalmology 2021To develop a classifier for differentiating between healthy and early stage glaucoma eyes based on peripapillary retinal nerve fiber layer (RNFL) thicknesses measured...
AIM
To develop a classifier for differentiating between healthy and early stage glaucoma eyes based on peripapillary retinal nerve fiber layer (RNFL) thicknesses measured with optical coherence tomography (OCT), using machine learning algorithms with a high interpretability.
METHODS
Ninety patients with early glaucoma and 85 healthy eyes were included. Early glaucoma eyes showed a visual field (VF) defect with mean deviation >-6.00 dB and characteristic glaucomatous morphology. RNFL thickness in every quadrant, clock-hour and average thickness were used to feed machine learning algorithms. Cluster analysis was conducted to detect and exclude outliers. Tree gradient boosting algorithms were used to calculate the importance of parameters on the classifier and to check the relation between their values and its impact on the classifier. Parameters with the lowest importance were excluded and a weighted decision tree analysis was applied to obtain an interpretable classifier. Area under the ROC curve (AUC), accuracy and generalization ability of the model were estimated using cross validation techniques.
RESULTS
Average and 7 clock-hour RNFL thicknesses were the parameters with the highest importance. Correlation between parameter values and impact on classification displayed a stepped pattern for average thickness. Decision tree model revealed that average thickness lower than 82 µm was a high predictor for early glaucoma. Model scores had AUC of 0.953 (95%CI: 0.903-0998), with an accuracy of 89%.
CONCLUSION
Gradient boosting methods provide accurate and highly interpretable classifiers to discriminate between early glaucoma and healthy eyes. Average and 7-hour RNFL thicknesses have the best discriminant power.
PubMed: 33747815
DOI: 10.18240/ijo.2021.03.10 -
Frontiers in Medicine 2021To evaluate the effect of femtosecond laser-assisted keratomileusis (FS-LASIK) on retinal fovea thickness, volume, and retinal nerve fibre layer (RNFL) thickness....
To evaluate the effect of femtosecond laser-assisted keratomileusis (FS-LASIK) on retinal fovea thickness, volume, and retinal nerve fibre layer (RNFL) thickness. Thirty-seven eyes (37 patients) undergoing FS-LASIK were included in this prospective study. Optical coherence tomography (OCT) was performed 1 day before, 1 h and 1 day after FS-LASIK surgery. Eighteen male and nineteen females were enrolled. Mean patient age was 22.94 ± 4.22 years. One hour postoperatively, macula fovea thicknesses, macula fovea volume, macula parafovea thickness, macula parafovea volume, macula perifovea thickness, macula perifove volume, temporal RNFL thickness, and superior RNFL thickness measures showed significant decrease ( = 6.171, 6.032, and 9.837, 9.700, 2.532, 4.393, 4.926, 2.265; = 0.000, 0.000, 0.000, 0.000, 0.016, 0.000, 0.000, and 0.011). Day 1 post-operation, macula fovea thicknesses, macula fovea volume, macula parafovea thickness, macula parafovea volume, and inferior RNFL thickness measures showed significant change compared to preoperative measures ( = 3.620, 3.220, 2.901, 2.910, 3.632; = 0.001, 0.003, 0.006, 0.006, and 0.001). Our data suggest there are alterations in retinal foveal and RNFL measurements by OCT 1 h and 1 day after FS-LASIK surgery.
PubMed: 34912833
DOI: 10.3389/fmed.2021.778666 -
BMC Oral Health Feb 2023The aim of this study was to compare the pushout bond strength (POBS) of three hydraulic cements, when used at thicknesses of 3 and 5 mm.
BACKGROUND
The aim of this study was to compare the pushout bond strength (POBS) of three hydraulic cements, when used at thicknesses of 3 and 5 mm.
METHODS
78 root slices of 3 and 5 mm of thickness were obtained from human teeth. Cylindrical cavities of 1.4 mm of diameter were drilled and filled with Biodentine (BD), Totalfill Root Repair paste (TF) or ProRoot MTA White (PMTA). Pushout tests were performed 21 days later. The fracture pattern of each sample was also analyzed. POBS data were analyzed with Welch and Brown-Forsythe and Tamhane's post hoc tests and a Weibull analysis was also performed.
RESULTS
In the 3 mm group, TF showed significantly lower bond strength than BD and PMTA. In the 5 mm group, BD showed significantly higher bond strength than TF. Both BD and TF showed higher bond strength when the thickness of the sample increased, while PMTA did not.
CONCLUSIONS
TF and BD achieve higher pushout bond strength resistance when used at a thickness of 5 mm than at 3 mm, while the mean resistance of PMTA is less influenced by the thickness. At 5 mm of thickness, BD and PMTA exhibit similar resistance to displacement. However, the behavior of BD is more predictable than that of its predecessor. BD is a reliable hydraulic cement for clinical situations where thick cavities need to be filled and displacement resistance plays an important role. Clinicians need to consider choosing specific hydraulic cements according to the thickness of material to be used.
Topics: Humans; Calcium Compounds; Dental Cements; Dental Cementum; Silicates; Dental Bonding; Materials Testing
PubMed: 36750823
DOI: 10.1186/s12903-023-02758-w -
American Journal of Ophthalmology May 2024To evaluate the association between scleral thickness and a newly developed multimodal imaging-based classification of central serous chorioretinopathy (CSC).
PURPOSE
To evaluate the association between scleral thickness and a newly developed multimodal imaging-based classification of central serous chorioretinopathy (CSC).
DESIGN
Retrospective, cross-sectional study.
METHODS
This study included 217 eyes of 217 patients classified as simple or complex CSC based on the established protocols. Clinical and anatomical factors were compared between the 2 types. The scleral thickness was measured at 4 locations using anterior-segment optical coherence tomography.
RESULTS
Of the 217 eyes, 167 were classified as simple CSC and 50 as complex CSC. The complex CSC group showed older age (P = .011), higher male ratio (P = .001), more bilateral involvement (P < .001), poorer visual acuity (P < .001), greater subfoveal choroidal thickness (P = .025), and higher frequency of loculation of fluid (P < .001) and ciliochoroidal effusion (P < .001) than the simple CSC group. The complex CSC group had significantly greater scleral thicknesses in the superior, temporal, inferior, and nasal directions (all P < .001) than the simple CSC group. Multivariable analysis revealed that older age (odds ratio [OR] 1.054, 95% confidence interval [CI] 1.013-1.097, P < .001), male sex (OR 10.445, 95% CI 1.151-94.778, P < .001), bilateral involvement (OR 7.641, 95% CI 3.316-17.607, P < .001), and the mean value of scleral thicknesses in 4 directions (OR 1.022, 95% CI 1.012-1.032, P < .001) were significantly associated with the complex CSC.
CONCLUSIONS
Older age, male sex, bilateral involvement, and thick sclera were associated with the complex CSC. Scleral thickness seemed to determine the clinical manifestations of CSC.
Topics: Humans; Male; Retrospective Studies; Central Serous Chorioretinopathy; Sclera; Cross-Sectional Studies; Fluorescein Angiography; Visual Acuity; Choroid; Tomography, Optical Coherence
PubMed: 38281567
DOI: 10.1016/j.ajo.2024.01.025 -
Frontiers in Physiology 2020Track cyclists are required to perform short- and long-term efforts during sprint and endurance race events, respectively. The 200 m flying sprint races require maximal...
Track cyclists are required to perform short- and long-term efforts during sprint and endurance race events, respectively. The 200 m flying sprint races require maximal power output and anaerobic capacity, while the 4,000 m pursuit cyclists demand a high level of aerobic capacity. Our goal was to investigate spatial changes in morphological and mechanical properties displayed using 3D topographical maps of the quadriceps muscle and tendons after 200 m flying start and 4,000 m individual pursuit race in elite track cyclists. We hypothesized a non-uniform distribution of the changes in the quadriceps muscle stiffness (QM), and acute alterations in quadriceps tendon (QT) and patellar tendon (PT) thickness. Fifteen men elite sprint and 15 elite men endurance track cyclists participated. Sprint track cyclists participated in a 200 m flying start, while endurance track cyclists in 4,000 m individual pursuit. Outcomes including QT (5-10-15 mm proximal to the upper edge of the patella), PT (5-10-15-20 mm inferior to the apex of the patella)-using ultrasonography evaluation, QM, and quadriceps tendon stiffness (QT) were measured according to anatomically defined locations (point 1-8) and patellar tendon stiffness (PT)-using myotonometry, measured in a midway point between the patella distal and the tuberosity of tibial. All parameters were assessed before and after (up to 5 min) the 200 m or 4,000 m events. Sprint track cyclists had significantly larger QT and PT than endurance track cyclists. analysis showed significant spatial differences in QM between rectus femoris, vastus lateralis, and vastus medialis in sprint track cyclists. At before race, sprint track cyclists presented significantly higher mean QT and PT, and higher QM and the QT, as compared with the endurance track cyclists. The observed changes in PT and QT were mostly related to adaptation-based vascularity and hypertrophy processes. The current study suggests that assessments using both ultrasonography and myotonometry provides crucial information about tendons and muscles properties and their acute adaptation to exercise. Higher stiffness in sprint compared with endurance track cyclists at baseline seems to highlight alterations in mechanical properties of the tendon and muscle that could lead to overuse injuries.
PubMed: 33381054
DOI: 10.3389/fphys.2020.607208 -
Frontiers in Veterinary Science 2023Pancreatic thickness is an indicator for evaluating pancreatic diseases. The transverse and cross-sectional pancreatic thickness observed on computed tomography (CT) may...
Pancreatic thickness is an indicator for evaluating pancreatic diseases. The transverse and cross-sectional pancreatic thickness observed on computed tomography (CT) may differ. This study aimed to provide a normal reference range for pancreatic thickness on the transverse plane based on body weight (BW) and assess pancreatic thickness to aorta (P/Ao) ratio. In addition, we aimed to establish the normal short and long dimensions of the pancreas based on cross-sectional image through the long axis of the pancreas using multiplanar reconstruction (MPR). The short dimension to aorta (S/Ao) and long dimension to aorta (L/Ao) ratios were also established in clinically normal dogs. The pancreatic thickness was measured using CT results of 205 clinically normal dogs. The pancreatic thickness on the transverse plane and the short and long dimensions in the cross-sectional image of the pancreas were measured using MPR. The diameter of the Ao was measured on the transverse plane and the P/Ao, S/Ao, and L/Ao ratios were calculated. Our study showed that the mean normal pancreatic thicknesses (mean ± standard deviation [SD]) of the pancreatic body, left and right lobe in the transverse plane were 10.92 ± 2.54 mm, 8.92 ± 2.26 mm and 9.96 ± 2.24 mm, respectively. The P/Ao ratios of the pancreatic body, left and right lobes were 1.85 ± 0.33, 1.50 ± 0.27 and 1.68 ± 0.29, respectively. The mean short dimension (mean ± SD) in the cross-sectional image of the pancreatic body, left and right lobe were 8.98 ± 1.97 mm, 7.99 ± 1.89 mm and 8.76 ± 2.03 mm, respectively. In conclusion, pancreatic thickness increased with BW, while the P/Ao, S/Ao, and L/Ao ratios could be used regardless of BW.
PubMed: 38026648
DOI: 10.3389/fvets.2023.1254672 -
Ophthalmology. Retina Oct 2022To examine widefield (WF) changes in the choroidal thickness of eyes with central serous chorioretinopathy (CSC). (Observational Study)
Observational Study
PURPOSE
To examine widefield (WF) changes in the choroidal thickness of eyes with central serous chorioretinopathy (CSC).
DESIGN
An observational study.
PARTICIPANTS
Twenty-two patients (20 men and 2 women) with treatment-naïve unilateral CSC and 28 normal eyes of 28 age-matched, healthy participants (21 men and 7 women).
METHODS
We performed enhanced depth imaging of swept-source (SS) OCT with a viewing angle of vertical 20 mm × horizontal 23 mm. Moreover, we developed a grid consisting of 9 subfields, with diameters of 3, 9, and 18 mm; the inner and outer rings were enclosed by circles with diameters of 3 and 9 mm and 9 and 18 mm, respectively, which were divided into 4 subfields-superotemporal, inferotemporal, superonasal, and inferonasal.
MAIN OUTCOME MEASURES
Widefield changes in choroidal thickness.
RESULTS
The mean duration from the presumed onset of CSC was 6.8 ± 3.1 months during the examination. Compared with that in normal eyes, the choroidal thickness in eyes of patients with CSC was significantly greater in all subfields (P < 0.020 for fellow eyes; P < 0.001 for eyes with CSC). Compared with that in fellow eyes, the choroidal thicknesses in eyes of patients with CSC were significantly greater, except for the outer superotemporal and inferonasal subfields (P < 0.001 for all inner subfields; P < 0.001 for the outer superonasal and inferotemporal subfields). In areas with dilated vortex veins, choroidal thickening was observed from the vicinity of the vortex vein ampulla to the macula along the course of the veins. Choroidal thickening on the dominant side was significantly greater than that on the nondominant side (P = 0.015 for the nasal subfield of the inner ring; P = 0.003 and P < 0.001 for the temporal subfields of the inner and outer rings, respectively).
CONCLUSIONS
Enhanced depth imaging of SS-OCT facilitated the analysis of WF changes in choroidal thickness in both healthy patients and patients with CSC. The local factors of the affected vortex vein and systemic risk factors may be involved in the pathogenesis of CSC.
Topics: Central Serous Chorioretinopathy; Choroid; Female; Fluorescein Angiography; Humans; Macula Lutea; Male; Tomography, Optical Coherence
PubMed: 35436598
DOI: 10.1016/j.oret.2022.04.011 -
Graefe's Archive For Clinical and... Dec 2021To evaluate structural and functional ocular changes in patients with type 2 diabetes mellitus (DM2) and moderate diabetic retinopathy (DR) without apparent diabetic...
PURPOSE
To evaluate structural and functional ocular changes in patients with type 2 diabetes mellitus (DM2) and moderate diabetic retinopathy (DR) without apparent diabetic macular edema (DME) assessed by optical coherence tomography (OCT) and microperimetry.
METHODS
This was a single-center cross-sectional descriptive study for which 75 healthy controls and 48 DM2 patients with moderate DR were included after applying exclusion criteria (one eye per patient was included). All eyes underwent a complete ophthalmic examination (axial length, macular imaging with swept-source OCT, and MAIA microperimetry). Macular thicknesses, ganglion cell complex (GCC) thicknesses, and central retinal sensitivity were compared between groups, and the relationships between the OCT and microperimetry parameters were evaluated.
RESULTS
Macular thickness was similar in both groups (242.17 ± 35.0 in the DM2 group vs 260.64 ± 73.9 in the control group). There was a diminution in the parafoveal area thickness in the DM2 group in the GCC complex. Retinal sensitivity was reduced in all sectors in the DM2 group. The central global value was 24.01 ± 5.7 in the DM2 group and 27.31 ± 2.7 in the control group (p < 0.001). Macular integrity was 80.89 ± 26.4 vs 64.70 ± 28.3 (p < 0.001) and total mean threshold was 23.90 ± 4.9 vs 26.48 ± 2.6 (p < 0.001) in the DM2 and control group, respectively. Moderate correlations were detected between the central sector of MAIA microperimetry and retina total central thickness (- 0.347; p = 0.0035). Age, visual acuity, and hemoglobin A1c levels also correlated with retinal sensitivity.
CONCLUSION
Macular GCC thickness and central retinal sensitivity were reduced in patients with moderate DR without DME, suggesting the presence of macular neurodegeneration.
Topics: Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Humans; Macular Edema; Retina; Tomography, Optical Coherence
PubMed: 34264395
DOI: 10.1007/s00417-021-05277-y