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Brazilian Oral Research Jun 2020This study evaluated the interference of enamel and coronal dentin thickness and ambient light in pulse oximetry interpretation, using SaO2the human finger as a...
This study evaluated the interference of enamel and coronal dentin thickness and ambient light in pulse oximetry interpretation, using SaO2the human finger as a reference. Forty-two intact human permanent mandibular molars were sectioned mesiodistally in the central portion. Buccal and lingual dentin surfaces were drilled, and 4 mm, 3 mm and 2 mm enamel/dentin thicknesses were interposed between finger and device, after which SaO2 levels were measured by finger pulse oximetry. A reference device was designed to align pulse oximeter light-emitting diode, buccal surface of tooth, little finger, lingual surface of tooth and photodiode. Variables were described as means and standard deviation, and the confidence interval was reported. Repeated measures analysis of variance (ANOVA) was used to compare the groups, followed by Bonferroni correction. Student t test for paired samples was used to determine presence of ambient light (α = 0.05). Mean SaO2 level was lower at 4.0 ± 0.2 mm thickness, regardless of presence or absence of ambient light (92.7% and 89.3%). The other thicknesses yielded values of 95.5% and 94.5% at 3.0 ± 0.2 mm, and 96.4% and 96.0% at 2.0 ± 0.2 mm (p < 0.001). There were significant differences between SaO2 values at 4.0 ± 0.2 mm, 3.0 ± 0.2 mm and 2.0 ± 0.2 mm thicknesses, in the presence of ambient light. Mean SaO2 level in positive control was 96.3%, and mean pulse rate was 69.5 bpm in presence of ambient light; in the absence of light, these values were 96% and 70.5 bpm. Enamel and dentin thickness interfere with SaO2, regardless of presence or absence of ambient light. The lowest SaO2 levels were found for the thickest tooth samples.
Topics: Dental Enamel; Dentin; Humans; Molar; Oximetry; Oxygen
PubMed: 32609233
DOI: 10.1590/1807-3107bor-2020.vol34.0064 -
Journal of Glaucoma Oct 2023The thicknesses of the circumpapillary retinal nerve fiber layer (cpRNFL) and ganglion cell complex (GCC) did not change during 5 years in physiological large disc...
Longitudinal Assessment of Retinal Nerve Fiber Layer and Ganglion Cell Complex Thicknesses in Patients With Large Optic Disc Cups and Normal Intraocular Pressure and Visual Fields.
PRCIS
The thicknesses of the circumpapillary retinal nerve fiber layer (cpRNFL) and ganglion cell complex (GCC) did not change during 5 years in physiological large disc cupping.
PURPOSE
We evaluated longitudinal changes in the thicknesses of the cpRNFL and GCC in large disc cupping with a normal intraocular pressure (IOP) (<21 mm Hg) and visual field.
METHODS
This retrospective, consecutive case series study included 269 eyes of 269 patients with large disc cupping and normal IOP. We analyzed patient demographics, IOP, central corneal thickness, vertical cup-to-disc ratios using color fundus photography, the thicknesses of the cpRNFL and GCC using RTVue-100, and mean deviation using visual field examinations.
RESULTS
The differences in IOP, vertical cup-to-disc ratios, and mean deviation between the baseline and each follow-up visit were not statistically significant. The baseline average and mean average at 60 months follow-up of the cpRNFL thickness were 106.5±8.5 and 105.1±9.3 μm, respectively; differences between the baseline and each follow-up visit were not statistically significant. The baseline average and mean average at 60 months follow-up of the GCC thickness were 82.8±9. and 81.5±9.2 μm, respectively; differences between baseline and each follow-up visit were not statistically significant.
CONCLUSIONS
The thicknesses of the cpRNFL and GCC did not change in well-maintained optic nerve head findings with normal IOP and visual field during a 5-year follow-up period. Optical coherence tomography evaluations of the thicknesses of the cpRNFL and GCC help accurately diagnose physiological optic disc cupping.
Topics: Humans; Optic Disk; Visual Fields; Retinal Ganglion Cells; Intraocular Pressure; Retrospective Studies; Nerve Fibers; Tomography, Optical Coherence
PubMed: 37327476
DOI: 10.1097/IJG.0000000000002253 -
Clinical & Experimental Optometry Jan 2016The objective was to investigate full retinal and inner retinal thickness in individuals with type 1 and type 2 diabetes.
BACKGROUND
The objective was to investigate full retinal and inner retinal thickness in individuals with type 1 and type 2 diabetes.
METHODS
Eighty-four individuals with type 1 diabetes (T1DM), 67 individuals with type 2 diabetes (T2DM) and 42 non-diabetic individuals (control group) were enrolled. Participants underwent full retinal thickness evaluation in the central retinal, parafoveal and perifoveal zones and in the retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC), using spectral domain optical coherence tomography. As a preliminary step, the key variables of interest - age, sex, diabetic retinopathy (DR), duration of diabetes and HbA1c levels - were analysed and compared between the three groups. Full retinal thickness, RNFL and GCC thicknesses were also compared between the groups. The relationship between the type of diabetes and retinal tissue thickness was explored, adjusting for the five potential confounders.
RESULTS
Compared to individuals with T1DM, individuals with T2DM had significantly reduced full retinal thickness in the parafovea and perifovea and reduced RNFL and GCC thickness. The mean differences were six (p = 0.020), seven (p = 0.008), six (p = 0.021) and four micrometres (p = 0.013) for the parafovea, perifovea, RNFL and GCC thicknesses, respectively. Thicknesses within the central zone (p = 0.018) and at the parafovea (p = 0.007) were significantly reduced in T2DM when compared to the control group. After adjusting for age, sex, diabetic retinopathy, duration of diabetes and HbA1c levels, the relationship between type of diabetes and retinal tissue thickness was not statistically significant (p > 0.056).
CONCLUSION
Retinal tissue thickness is not significantly different between type 1 and type 2 diabetes, when adjusted for age, sex, diabetic retinopathy, duration of diabetes and HbA1c levels.
Topics: Aged; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Glycated Hemoglobin; Humans; Middle Aged; Retina
PubMed: 26875856
DOI: 10.1111/cxo.12318 -
Surgical and Radiologic Anatomy : SRA Nov 2021The present study aims to evaluate the superior semicircular canal (SSC) bone thickness and radiological patterns in relation to age and gender in a Turkish population...
PURPOSE
The present study aims to evaluate the superior semicircular canal (SSC) bone thickness and radiological patterns in relation to age and gender in a Turkish population using cone beam computed tomography (CBCT).
METHODS
A total of 450 temporal bones were evaluated in the study by two examiners. The radiological patterns of SSC were categorized as follows: dehiscent, papyraceous, normal, thick and pneumatised patterns. The bone thickness of SSCs were measured.
RESULTS
The mean bone thickness of the SSC for females was 1.079 ± 0.8 mm. For males, the mean bone thickness was 0.952 ± 0.6 mm. There was no significant difference between males and females for the mean bone thickness of the SSC. (p > 0.05) The normal pattern was found in 258 temporal bones (57.3%). Seventy-two cases (16%) were defined as "papyraceous pattern"; 23 cases (5.1%) were defined as "thick pattern" and 42 cases (9.3%) were defined as "pneumatised pattern". SSC dehiscence was determined in 55 cases (12.2%). There was no significant difference between radiological patterns for age groups and gender (p > 0.05).
CONCLUSION
There was no significant relationship between SSC bone thickness with age and gender. The radiological patterns of SSC were not associated with age and gender. Radiologists evaluating the head and neck region for various reasons should be aware of these structures and report not only the SSC dehiscence but also the papyraceous pattern.
Topics: Cone-Beam Computed Tomography; Female; Head; Humans; Male; Neck; Semicircular Canals; Temporal Bone
PubMed: 34241668
DOI: 10.1007/s00276-021-02797-4 -
Journal of Prosthodontics : Official... Dec 2020To assess the effect of yttria mol% concentration and material thickness on the biaxial fracture load (N) of zirconia with and without mastication simulation.
PURPOSE
To assess the effect of yttria mol% concentration and material thickness on the biaxial fracture load (N) of zirconia with and without mastication simulation.
MATERIALS AND METHODS
Disk-shaped specimens (N = 120) of 3 mol% yttria-partially stabilized zirconia, 3Y-PSZ (Katana High Translucent, Kuraray Noritake), 4 mol% yttria-partially stabilized zirconia, 4Y-PSZ (Katana Super Translucent Multi Layered) and 5 mol% Yttria-partially stabilized zirconia, 5Y-PSZ (Katana Ultra Translucent Multi Layered) were prepared to thicknesses of 0.7 and 1.2 mm. For each thickness, the biaxial fracture load (N) was measured with and without mastication simulation with 1.2 million cycles at a 110-N load and simultaneous thermal cycling at 5°C to 55°C. The data were analyzed by three-way Analysis of Variance (α = 0.05) and Tukey-Kramer adjusted multiple comparison test.
RESULTS
Yttria mol% concentration and material thickness had a statistically significant effect on the mean biaxial fracture load (F = 388.16, p < 0.001 and F = 714.33, p < 0.001 respectively). The mean biaxial fracture load ranged from the highest to the lowest; 3Y-PSZ, 4Y-PSZ, and 5Y-PSZ (p = 0.012). The mean biaxial fracture load of the 1.2 mm thickness groups was significantly higher than 0.7 mm thickness at any given condition (p = 0.002). Not all specimens survived the mastication simulation protocol. Fifty percent of the 0.7-mm-thick 4Y-PSZ specimens, 70% of the 0.7-mm-thick 5Y-PSZ specimens and 20% of 1.2-mm-thick 5Y-PSZ specimens fractured during mastication simulation. Mastication simulation had no statistically significant effect on the biaxial fracture load (F = 1.24, p = 0.239) of the survived specimens.
CONCLUSIONS
Lowering yttria mol% concentration and increasing material thickness significantly increases the fracture load of zirconia. At 0.7 mm thickness, only 3Y-PSZ survived masticatory simulation. A minimum material thickness of 1.2 mm is required for 4Y-PSZ or 5Y-PSZ.
Topics: Dental Materials; Dental Stress Analysis; Mastication; Materials Testing; Zirconium
PubMed: 32840940
DOI: 10.1111/jopr.13242 -
European Journal of Obstetrics,... May 2024Increasing placental thickness is associated with adverse outcomes including earlier gestational age at delivery, lower birthweight, and lower umbilical artery pH. We...
OBJECTIVE
Increasing placental thickness is associated with adverse outcomes including earlier gestational age at delivery, lower birthweight, and lower umbilical artery pH. We aim to determine whether mid-trimester placenta previa thickness is associated with persistence of previa at time of delivery.
STUDY DESIGN
Single-center retrospective cohort study of singleton gestations with previa diagnosed at 18-24 weeks delivering between 2015 and 2019. The thickest portion of the placenta was measured in a longitudinal plane on transabdominal imaging to determine placental thickness. We defined three cohorts: 1) thick placenta (>1 standard deviation above the mean), 2) thin placenta (>1 standard deviation below the mean), and 3) average placenta (within 1 standard deviation above or below the mean). Primary outcome was previa persistence at time of delivery. Secondary outcomes included postpartum hemorrhage, cesarean delivery, placenta accreta spectrum, and maternal morbidity composite (use of Bakri balloon, B-lynch, or O'Leary, peripartum hysterectomy, blood transfusion, ICU admission, or death). In all analyses, average thickness was used as the base comparator.
RESULTS
Of 239 pregnancies with mid-trimester previa there were 34 thin, 166 average, and 39 thick placentas. Patients with thick placenta were older, more likely to have prior cesarean delivery, fibroid uterus, and delivery at an earlier gestational age. After adjusting for confounders, thick placenta was associated with persistent previa (aOR 6.85 [3.13-15.00]) and cesarean delivery (aOR 2.76 [1.26-6.08]).
CONCLUSION
At diagnosis of mid-trimester previa, thick placenta is associated with persistence at time of delivery and delivery by cesarean section. This suggests placental thickness may assist with risk stratification and coordination of care.
Topics: Pregnancy; Humans; Female; Cesarean Section; Placenta Previa; Retrospective Studies; Placenta; Ultrasonography; Placenta Accreta
PubMed: 38401448
DOI: 10.1016/j.ejogrb.2024.02.033 -
European Journal of Ophthalmology May 2022To investigate the quantitative sectoral and regional changes of retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) thickness in different...
How do intracranial tumors associated with visual pathways affect quadrant and sectoral based optical coherence tomography measurements: The effect of intracranial tumors on RNFL and GC-IPL thickness.
AIM
To investigate the quantitative sectoral and regional changes of retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) thickness in different types of intracranial tumors associated with visual pathways.
METHODS
This comparative retrospective study included 58 eyes of 30 patients with intracranial tumors and the data of 62 eyes of 31 healthy subjects. The RNFL and GCIPL thicknesses were analyzed using spectral-domain optical coherence tomography (OCT). The tumors were classified into ones that affect pre-geniculate and post-geniculate pathway.
RESULTS
The mean RNFL thickness in temporal quadrant was significantly thinner in eyes with intracranial tumors affecting the pre-geniculate optic pathway compared to controls ( 0.04). In contrast, the mean superior quadrant RNFL thickness was significantly thicker in eyes with brain tumors associated with post-geniculate optic pathway ( 0.01). The mean GC-IPL thicknesses of the inner ring superotemporal, superonasal, inferotemporal and inferionasal sectors and outer ring superonasal and inferonasal sectors were significantly thinner in eyes with intracranial tumors affecting the pre-geniculate optic pathway compared to control eyes ( = 0.02, = 0.001, = 0.02, = 0.003, = 0.008 and = 0.03 respectively).
CONCLUSION
The results of this study showed that significant changes can be seen in the different RNFL quadrants and GC-IPL sectors in eyes with intracranial tumors affecting pre-geniculate or post-geniculate optic pathway. OCT is a very useful imaging technique to quantify these structural changes which take place during the neurodegeneration process of visual pathways in intracranial tumors.
Topics: Brain Neoplasms; Humans; Nerve Fibers; Retinal Ganglion Cells; Retrospective Studies; Tomography, Optical Coherence; Visual Pathways
PubMed: 34162240
DOI: 10.1177/11206721211028035 -
Arquivos Brasileiros de Oftalmologia 2022The purpose of this study was to evaluate the intraretinal layer thickness in the macular region and its correlation with the duration of uveitis and visual acuity in...
PURPOSE
The purpose of this study was to evaluate the intraretinal layer thickness in the macular region and its correlation with the duration of uveitis and visual acuity in patients with Behçet uveitis.
METHODS
In this cross-sectional study, we included 93 eyes of 57 patients with Behçet uveitis and 100 eyes of 50 healthy individuals admitted to a tertiary center from January to September 2017. We performed macular measurements in all subjects via spectral domain-optical coherence tomography (SD-OCT) and divided the retina into layers using automated segmentation software on the SD-OCT device. We then compared layer thicknesses between the patient and control groups and evaluated the correlation between OCT parameters and the duration of uveitis and visual acuity in the patient group.
RESULTS
Our records show a mean age of 37.9 ± 10.8 (18-64) years and 37.7 ± 12.2 (21-61) years in the patient and control groups (p=0.821), respectively. Meanwhile, data reveal a mean duration of uveitis of 6.9 ± 4.7 (1-20) years. We found a reduction in the total outer layer thickness in the patient group (p<0.001). However, we did not find a statistically significant difference in the inner retinal layers except in the inner nuclear layer. The duration of uveitis negatively correlated with the outer retinal layer's thickness (correlation coefficient = -0.250). On the other hand, visual acuity positively correlated with the central macular, the total inner layer, and the outer retinal layer thicknesses (correlation coefficients: 0.194, 0.154, and 0.364, respectively). However, the inner nuclear layer negatively correlated with visual acuity.
CONCLUSIONS
Using retinal segmentation via SD-OCT for follow-ups can help estimate visual loss in patients with Behçet uveitis, which can cause significant changes in intraretinal layers in the macular region.
Topics: Humans; Adult; Middle Aged; Cross-Sectional Studies; Retina; Behcet Syndrome; Uveitis; Visual Acuity; Tomography, Optical Coherence
PubMed: 36169428
DOI: 10.5935/0004-2749.2021-0174 -
Current Eye Research Nov 2017The aim of this study was to evaluate anatomic properties of the lens capsule and iris by anterior segment optical coherence tomography (AS-OCT) in patients with...
PURPOSE
The aim of this study was to evaluate anatomic properties of the lens capsule and iris by anterior segment optical coherence tomography (AS-OCT) in patients with pseudoexfoliation (PEX).
METHODS
This prospective study included 62 eyes of 62 patients with PEX syndrome and 43 eyes of 43 age- and gender-matched controls. All subjects underwent full ophthalmologic examinations including AS-OCT. Pupillary diameter, midperipheral stromal iris thickness, central and temporal lens capsule thicknesses, and peripheral pseudoexfoliation material thickness on the anterior lens capsule surface were measured and recorded.
RESULTS
Mean age was 66.8 ± 9.3 years in the PEX group and 65.5 ± 8.9 years in the control group (p = 0.44). The PEX group consisted of 62 patients: 38 men (61.3%) and 24 women (38.7%); the control group included 43 subjects: 25 men (58.1%) and 18 women (41.9%). Pupillary diameter after pharmacologic mydriasis was 21% smaller in the PEX group than controls. Mean midperipheral iris thickness was 36 ± 7.2 μm (7.8%) thinner in the PEX group than that of control group (p = 0.047). The central anterior capsule was a mean of 3.40 ± 0.51 μm (18%) thicker in the PEX group compared to the control group (p = 0.0001). The temporal anterior lens capsule was a mean of 0.17 ± 0.15 μm thicker in the PEX group compared to the control group (p = 0.81).
CONCLUSIONS
With high-resolution OCT imaging, it has become possible to evaluate the anterior lens capsule without histologic examination and demonstrate that it is thicker than normal in PEX patients.
Topics: Aged; Anterior Capsule of the Lens; Disease Progression; Exfoliation Syndrome; Female; Humans; Iris; Male; Prospective Studies; Severity of Illness Index; Tomography, Optical Coherence
PubMed: 28910163
DOI: 10.1080/02713683.2017.1338349 -
Journal of Ophthalmology 2021To evaluate the differences in macular choroidal thickness and volume among patients with pseudoexfoliative glaucoma (PXG), patients with primary open-angle glaucoma...
PURPOSE
To evaluate the differences in macular choroidal thickness and volume among patients with pseudoexfoliative glaucoma (PXG), patients with primary open-angle glaucoma (POAG), and controls.
METHODS
A total of 50 PXG patients (50 eyes) and 56 POAG patients (56 eyes) were selected as the PXG group and the POAG group, respectively, in this case-control study. A total of 54 age-, gender-, IOP-, and axial length-matched healthy individuals (54 eyes) were selected as the control group. Enhanced-depth imaging-optical coherence tomography (EDI-OCT) was used to measure and analyze the choroidal thicknesses and volumes in 9 macular regions of all subjects.
RESULTS
The choroidal thicknesses in the central subfield (CSM), temporal inner macula (TIM), inferior inner macula (IIM), and temporal outer macula (TOM) and the mean macular choroidal thickness were significantly thinner in the PXG group than in the control group (all < 0.05). The choroidal volumes in the TIM, IIM, and TOM and the mean macular choroidal volume were significantly smaller in the PXG group than in the control group (all < 0.05). The choroidal thicknesses in the CSM and IIM and the mean macular choroidal thickness were significantly thinner in the PXG group than in the POAG group (all < 0.05). The choroidal volumes in the IIM and TOM and the mean macular choroidal volume were significantly smaller in the PXG group than in the POAG group (all < 0.05). Multivariable linear regression analysis showed that the mean macular choroidal thickness was significantly thinner in association with older subjects and longer axial length eyes. There was no association between the macular choroidal thickness of various macular regions and visual field mean defect (MD) in groups PXG and POAG (all > 0.05).
CONCLUSIONS
The macular choroidal thicknesses and volumes (inferior and temporal) in PXG patients were thinner and smaller than those in POAG patients and healthy individuals. The role of choroidal thickness changes in the course of PXG remains unclear. A future prospective study is needed to better define these changes in PXG patients.
PubMed: 34824868
DOI: 10.1155/2021/3897952