Mean Root Mean Square Values Research Articles

A comparative biomechanical study of original and compatible titanium bases: evaluation of screw loosening and 3D-crown displacement following cyclic loading analysis.

PURPOSEThis study evaluated screw loosening and 3D crown displacement after cyclic loading of implant-supported incisor crowns cemented with original titanium bases or with three compatible, nonoriginal components.MATERIALS AND METHODSA total of 32 dental implants were divided into four groups (n = 8 each): Group 1 used original titanium bases, while Groups 2-4 used compatible components. The reverse torque value (RTV) was evaluated prior to and after cyclic loading (1,200,000 cycles). Samples (prior to and after cyclic loading) were scanned with a microcomputed tomography (micro-CT). Preload and postload files were superimposed by 3D inspection software, and 3D crown displacement analysis was performed using root-mean-square (RMS) values. All datasets were analyzed using one-way ANOVA and Tukey’s post hoc analysis.RESULTSSignificant variations were observed in the postload RTV, depending on the titanium base brand (P < .001). The mean postload RTVs were significantly higher in Groups 1 and 2 than in the other study groups. While evaluating 3D crown displacement, the lowest mean RMS value was shown in the original Group 1, with the highest RMS value occurring in Group 4.CONCLUSIONWithin the limitations of this in vitro study and under the implemented conditions, it was concluded that the manufacturer brand of the titanium base significantly influenced screw loosening following the fatigue test and influenced 3D crown displacement after cyclic loading.

Balance Control Strategies during Perturbed Standing after a Traumatic Brain Injury: Kinematic Analysis.

The objective of the current investigation was to examine the presence, absence or alteration of fundamental postural control strategies in individuals post traumatic brain injury (TBI) in response to base of support perturbations in the anterior-posterior (AP) direction. Four age-matched healthy controls (age: 46.50 ± 5.45 years) and four individuals diagnosed with TBI (age: 48.50 ± 9.47 years, time since injury: 6.02 ± 4.47 years) performed standing on instrumented balance platform with integrated force plates while 3D motion capture data was collected at 60 Hz. The platform was programmed to move in the AP direction, during a sequence of 5 perturbations delivered in a sinusoidal pattern at a frequency of 1 Hz, with decreasing amplitudes of 10, 8, 6, 4, and 2 mm respectively. The sagittal plane peak-to-peak range and root mean square (RMS) of the hip, knee, and ankle joint angles during the 5 seconds of perturbation were computed from optical motion capture data. The TBI group had a higher mean range (5.17 ± 1.91°) about the ankle compared to the HC group (4.17 ± 0.81°) for the 10mm perturbation, but their mean range was smaller than the HCs for the other 4 conditions. About the hip, the TBI group's mean range was larger than the HC's for all conditions. For both groups, the mean range decreased with perturbation amplitude for all conditions. The TBI group showed larger changes in mean range and RMS values as the amplitude of the perturbation changed, while the HC group showed smaller intertrial changes. The results suggest that the TBI group was substantially more reliant on the hip strategy to maintain balance during the perturbations and this reliance was well linked with perturbation amplitude.Clinical Relevance- Existing information regarding changes in postural control strategies in individuals post TBI is limited. The current work demonstrates lower limb kinematic differences between HC and TBI and some preliminary evidence on increased hip movement in the TBI group.

Influence of Liquid on the Tooth Surface on the Accuracy of Intraoral Scanners: An In Vitro Study.

To assess the influence of liquid attached on the tooth surfaces on the accuracy (trueness and precision) of intraoral scanners and the effectiveness of the drying method (using compression air) to exclude the influence of liquid on the scanning results. A mandibular jaw model was scanned using an industrial computed tomography scanner to obtain a reference model. A scanning platform was designed to simulate three specific tooth surface states (dry, wet, blow-dry). Two kinds of liquids (ultra-pure water and artificial saliva) were used for the test. Two intraoral scanners (Trios 3 and Primescan) were used to scan the mandibular jaw model 10 times under each condition. All scanning data were processed and analyzed using dedicated software (Geomagic Control 2015). Trueness and precision comparison were conducted within the 12 groups of 3D models divided based on different intraoral scanners and liquids used under each condition. The root mean square (RMS) value was used to indicate the difference between the aligned virtual models. The color maps were used to evaluate and observe the deviation distribution patterns. The 3-way ANOVA (condition, intraoral scanner, liquid) followed by the Tukey test were used to assess precision and trueness. The level of significance was set at 0.05. The mean RMS values obtained from wet condition were significantly higher than those of the dry and blow-dry condition (p < 0.001, F = 64.033 for trueness and F = 54.866 for precision), which indicates less accurate trueness and precision for wet condition. For two different types of liquids, the mean RMS value was not significantly different on trueness and precision. The deviations caused by liquid were positive and mainly distributed in the pits and fissures of the occlusal surface of posterior teeth, the interproximal area of the teeth, and the margin of the abutments. Liquid on the tooth surface could affect intraoral scanning accuracy. Blow-drying with a three-way syringe can reduce scanning errors.

Electromyographic Analysis of Gluteus Medius Activity in People with Non-Specific Chronic Low Back Pain Compared to Healthy Controls

Background and Objectives: The functioning of the hip and trunk muscles has an effect on low backregion. Gluteus medius (Gmed) being the primary hip abductor plays a significant role in maintaining thestability of the pelvis. Despite the significance, this muscle activity is least addressed and is also thoughtto be one among the major causes of pain in the low back. The aim of the study was to compare theactivity of Gmed in non-specific chronic low back pain (NSCLBP) and healthy individuals using SurfaceElectromyography (SEMG).Methods: 506 subjects were screened, of which 200 subjects were selected. Group A: NSCLBP (n=100)and GROUP B: Healthy controls (n=100). Both groups were instructed to perform maximum voluntarycontractions. The mean root mean square (RMS) value of Gmed muscle activity for the exercise task wasrecorded and analyzed using SEMG.Results: The results demonstrated that the mean RMS value of the right Gmed muscle activity for GROUPA was lesser (53.00 ± 24.81) than GROUP B (87.9 ± 37.47). The mean RMS value of the left Gmed activitywas also lesser for GROUP A (55.99 ± 27.21) compared to GROUP B (89.72 ± 39.83). The difference inmeans between the two groups showed highly significant outcome (P<0.001).Conclusion: The study concluded that the muscle activity of Gmed between the groups was lesser in GroupA compared to Group B indicating differential activation of the muscle in people with NSCLBP. However,there was no significant difference in mean RMS value of the right and left Gmed muscle activity whencompared within the groups respectively.

Comparison of three different types of exercises for selective contractions of supra- and infrahyoid muscles

Several exercise methods, such as the Shaker exercise, tongue press exercise, chin tuck against resistance (CTAR) exercise, and submandibular push exercise, have been introduced to strengthen the muscles involved in swallowing. In this study, we compared the effectiveness of the CTAR, submandibular push, and Shaker exercises for the induction of selective supra- and infrahyoid muscle contractions using surface electromyography (EMG). This study is a prospective non-randomized controlled study. Twenty-five healthy subjects and 20 patients experiencing swallowing difficulty were enrolled. During the three different types of exercises, the root mean square (RMS) values of the sternocleidomastoid (SCM), suprahyoid (anterior belly of the digastric and mylohyoid muscles), and infrahyoid (sternothyroid and thyrohyoid muscles) muscles were analyzed using surface EMG. Differences in the activity of swallowing muscles among the three different exercises were analyzed using one-way repeated measured analysis of variance. In terms of both the maximum and mean RMS values of the suprahyoid muscle, the submandibular push exercise showed a larger RMS value than the CTAR and Shaker exercises in healthy subjects (p < 0.05). In terms of both the maximum and mean RMS values of the suprahyoid muscle, the Shaker exercise and submandibular push exercise showed a larger RMS value than the CTAR exercise in patients with swallowing difficulty (p < 0.05). The submandibular push exercise may be effective as a swallowing muscle exercise owing to its superiority in inducing selective contractions of the supra- and infrahyoid muscles. The CTAR and Shaker exercises are also effective in this regard.

Facial scanner accuracy with different superimposition methods - In vivo study.

To compare trueness and precision between conventional and digital facial measurements and to evaluate the accuracy of different superimposition techniques for facial scans. Twenty volunteers were recruited. Predetermined facial landmarks were marked with a black pen, and the interlandmark distances were measured manually with a conventional caliper and digitally with Geomagic software. Two consecutive facial scans were performed and superimposed using as best-fit reference the full face, the face without the eyes, and the bone-supported areas (eg, forehead and zygomatic areas) in order to assess root mean square (RMS) differences. Trueness and precision were evaluated and compared between the conventional and digital techniques. Mann-Whitney U and Kruskal-Wallis post hoc tests were used. The significance level was established at α = .05. Trueness between conventional and digital measurements was 1,151.75 ± 1,265.52 μm (3.04% ± 4.82%), and precision was 322.31 ± 300.54 μm (0.93% ± 1.10%). Global mean RMS values for each superimposition technique were 334.15 ± 172.07 for the full face, 339.57 ± 173.13 for the face without the eyes, and 385.65 ± 182.29 for the bone-supported areas, with the latter presenting statistically significant differences compared to the other two. Although statistically significant differences were detected in facial measurements, they were below the clinically detectable threshold. Superimposition with the full face and the face without the eyes area presented smaller discrepancies than with the bone-supported areas, with higher discrepancies in the lower third of the face.

Analysis of Influencing Factors of Single Camera Photogrammetry in Forensic Three-Dimensional Reconstruction

Objective To evaluate the influence of factors such as the selection of equipment, focal length and the selection of reconstruction quality in the reconstruction software on the reconstruction results of single camera photogrammetry and provide reference for the forensic application of single camera photogrammetry. Methods The 19 skulls were measured by traditional measurement method and single camera photogrammetry. The differences between the two measurement methods and within the group with same equipment but different focal length were analyzed. One skull and one corpse were selected as the research objects. According to the reconstruction quality selection conditions in the photogrammetric software, the experimental group was divided into five grades. The model reconstructed by optical scanner was defined as reference model, while the model reconstructed by single camera photogrammetry was defined as test model. The test model was aligned with the reference model, 3D deviation analysis was carried out and the mean error and root mean square （RMS） values were calculated. Results The differences between EOS 7D zoom group and traditional measurement, and within the group with same equipment had statistical significance （P<0.05）. The mean error value and minimum RMS value of the skull reconstructed by single camera photogrammetry and the three-dimensional model of the corpse existed in the medium quality group, and the trend was basically the same. Conclusion The equipment and focal length has no obvious influence on the results of single camera photogrammetry. Lower reconstruction quality can easily cause distortion, while higher reconstruction quality can easily generate noise, so medium quality is preferred.

Topside Ionosphere of NeQuick2 and IRI‐2016 Validated by Using Onboard GPS Observations From Multiple LEO Satellites

AbstractAn accurate description of the topside ionosphere is of great importance for space weather applications. Currently, there are two commonly used empirical ionosphere models, that is, NeQuick2 and IRI‐2016, that can be used to describe the topside ionosphere. In this study, topside total electron content (TEC) values derived from low Earth orbit (LEO) satellites are selected to validate the topside ionosphere predictions of the NeQuick2 and IRI‐2016 models from 2008 to 2018. The results show that these two models both underestimate the topside ionosphere. Compared with the global topside ionosphere model estimated by LEO‐based global positioning system (GPS) observations with orbital altitudes of 500 and 800 km, NeQuick2 and IRI‐2016 have similar performances over different latitudes and longitudes. The daily mean root mean square (RMS) values are approximately 4.10 and 2.10 TEC units (TECU) for the region above 500 and 800 km, respectively. The results assessed by the GPS‐TEC technique indicate that the performance of the NeQuick2 model is slightly better than that of the IRI‐2016 model. The daily mean bias mainly ranges from −1.5 to 1.5 and −3.0 to −1.0 TECU for the regions above 500 and 800 km, respectively. The RMS values for the corresponding parts are 3.50 and 2.74 TECU. Finally, the validation results of the dSTEC method show that the mean bias is −0.43 and −0.20 TECU above 500 and 800 km, respectively. The mean RMS values are 2.04 and 0.72 TECU for the corresponding regions.

Effect of the submandibular push exercise using visual feedback from pressure sensor: an electromyography study

We developed a new exercise method called the submandibular push exercise that can strengthen the suprahyoid muscle by inducing only the motion of the hyoid bone without neck flexion. In this study, we aimed to investigate and compare the muscle activity of the suprahyoid and infrahyoid muscles in the course of performing three different swallowing exercises. Twenty healthy participants and fifteen patients with dysphagia were recruited. Each participant consecutively performed three exercises: Shaker, CTAR, and submandibular push exercises. To investigate muscle activation, surface electromyography was performed on the suprahyoid, infrahyoid, and SCM muscles, during the exercises. Root mean square (RMS) was measured. In healthy participants, the submandibular push exercise showed a significantly higher RMS value in the suprahyoid and infrahyoid muscles than the Shaker and CTAR exercises using repeated ANOVA with Tukey's post hoc test (p < 0.05). In patients with dysphagia, the submandibular push and Shaker exercises showed significantly higher RMS value in the suprahyoid and infrahyoid muscles than the CTAR exercise. However, no significant difference was found between the submandibular push and Shaker exercises. In both healthy and patients with dysphagia, the mean RMS values of the SCM muscles during the submandibular push exercise were significantly lower than those during the Shaker exercise using repeated ANOVA with Tukey's post hoc test (p < 0.05). In conclusion, considering the relatively superior selectiveness in suprahyoid and infrahyoid muscle contraction, the submandibular push exercise using visual feedback from pressure sensor could be an efficient supplementary exercise to the conventional swallowing muscle exercises. However, further studies may be necessary to confirm the improvement in swallowing difficulty.

Accuracy evaluation of the latest BDGIM for BDS-3 satellites

A novel model of the BeiDou Global Ionospheric delay correction Model (BDGIM) is used as the global broadcasting ionospheric correction model for the third generation of BeiDou Navigation Satellite System (BDS-3). It has been successfully implemented on five BDS-3 test satellites. The accuracy of this novel BDGIM model were evaluated using the final global ionosphere maps (GIM) products provided by the International Global Navigation Satellite System Service (IGS). Comparing with the IGS GIM final product, the root mean square (RMS) of the global correction accuracy of BDGIM was 3.57 total electron content unit (TECu) with a correction percentage of 77.2%. The average RMS at different latitudes was 3.11 TECu, with Percent of 75.2%. The mean RMS values of regions with lattilute larger than 52.5S and 62.5N were less than that of NeQuickG. Considering the distribution of the tracking stations using for calculating BDGIM coefficients, the RMS values in different regions were 3.09 TECu (Percent = 80.3%) and 3.21 TECu (Percent = 79.4%), respectively. The BDGIM coefficients was updated every two hours, comparing with NeQuickG model, the BDGIM better reflected the real changes of ionosphere. Considering that the accuracy of the non-broadcasted coefficients declines with broadcasting duration, the correction accuracy with nine broadcasted coefficients included in BDGIM was analyzed. RMS and Percent were 4.10 TECu and 72.8%, declining by about 0.53 TECu and 4.4% (maximum to 9.7%), respectively.

Assessment of reproducibility and reliability of facial expressions using 3D handheld scanner

PurposeThe three-dimensional morphological analysis of facial expressions has been becoming increasingly common and hand-held three-dimensional scanners can be advantageous in data acquisition due to their mobility. The aim of the present study was to test intra-subject, intra-observer and inter-observer reproducibility and reliability of a hand-held scanner during facial expressions. Materials and methodsIn order to investigate intra-subject reproducibility and reliability, we performed face scanning two times on 30 healthy subjects at three-month intervals. In addition, two observers scanned twice the face of 10 healthy subjects consecutively to evaluate intra-observer and inter-observer differences. Scannings were performed during facial expressions. Face asymmetry and severity of facial expression were determined using root mean square (RMS) value. Repeated-measurement ANOVA was used to test the reproducibility and correlation coefficient to determine the reliability of the facial expressions. ResultsThe mean RMS values measured at different times were not significantly different for any facial expression (p > 0.05). The reliability of the measurements was variable depending on the facial expression (r = 0.47 and 0.98, p < 0.05). ConclusionsOur study may contribute to the development of new techniques for examining facial expressions. Hereby, morphological analysis may be possible in the clinic and at the bedside without the need for laboratory conditions.

Atomic force microscopy analysis of the effect of plasma treatment on gas permeable contact lens surface topography.

Using atomic force microscopy (AFM) to investigate anterior surface topography (AST) in worn and unworn, plasma surface-treated (PST) and untreated (UT) gas permeable (GP) lenses, and influence of surface topography on in vivo comfort. GP lens AST evaluated with AFM in tapping mode, using an uncoated, 40 nm symmetric tip (sampling frequency: 300 kHz), at five randomised locations, over a 100μm2 area, to produce mean average roughness (Ra) and root mean square (RMS) values for each sample. Four unworn lenses (two PST, two UT) were examined (Quasar/Boston EO material). Twenty worn lenses (ten PST, ten UT) of same design and material as unworn lenses collected after 3 months lens wear. General wearing comfort reported by visual analogue scale (VAS) at 3 months visit. For sample preparation, two worn UT GP lenses were divided into four segments; each segment underwent a different lens rinse and drying method. Unworn: UT lenses had significantly higher mean RMS and Ra values compared to PST (Mann-Whitney, p < 0.05). Worn: UT Median RMS values were significantly higher than PST (Mann-Whitney, p < 0.05). Comfort: no correlation found between general comfort and RMS or Ra scores. Sample preparation: Method 4 (purified, distilled water rinse/nitrogen gas dry) produced optimum median RMS and Ra values. Unworn PST GP lenses had lower Ra and RMS values compared with unworn UT GP lenses. After 3 months wear, PST lenses had smoother surface topographies than UT lenses. No relationship was found between surface topography and lens wear comfort. Sample preparation protocol directly impacts AFM results.

An adaptive Kalman filter based on variance component estimation for a real-time ZTD solution

The Global Navigation Satellite System (GNSS) precise point positioning (PPP) technology is currently used to process GNSS water vapor observations in real time or near real time. Further developments are required to improve the accuracy and real-time performance of processing tropospheric delays from which the water vapor observations are extracted. In real-time BDS/GPS precise clock correction estimation with square-root information filtering and PPP solution with Kalman filtering, a fixed variance is often assigned for the process noise of the troposphere dynamics model. However, this fixed value may deviate from reality as the weather conditions change, especially for extreme weather. In this paper, a new adaptive Kalman filter is proposed for tropospheric delay processing, in which the variance of the process noise for the zenith tropospheric delay (ZTD) dynamics model is tuned in real time using the least-squares variance component estimation technique. MGEX/IGS data of 15 consecutive days were processed in a stepwise manner. Namely: Real-time BDS/GPS precise clock corrections were estimated firstly, followed by comparison among ZTD solutions of four schemes based on these real-time clocks of first step and GFZ multi-GNSS precise clock (GBM) final clocks: (1) real-time solution of ZTD (G(GPS), GC(GPS and BDS)) without VCE; (2) real-time solution of ZTD (G, GC) with VCE; (3) final solution of ZTD (G, GC, GR (GPS and GLONASS), GE (GPS and GALILEO), GRC (GPS, GLONASS and BDS), GREC (GPS, GLONASS, GALILEO and BDS) without VCE; and (4) final solution of ZTD (G, GC, GR, GE, GRC, GREC) with VCE. The performance of the ZTD and positioning solution was analyzed. Results showed that the accuracy of estimated real-time satellite clock correction was 0.27, 1.31, 0.29, and 0.21 ns for GPS, BDS/GEO, BDS/IGSO, and BDS/MEO, respectively. For the ZTD solutions, the results of schemes 1 and 2 were 12.8 mm (GC) and 10.1 mm (GC) in terms of mean root-mean-square (RMS) values and 2.1 mm (GC) and 1.6 mm (GC) in terms of minimum RMS values, respectively, thereby showing an improvement for scheme 2 of 1.8–81.4% over scheme 1 with average increasing rates of 20.7% (GC) and 20.2% (G). The results for schemes 3 and 4 were 7.6 mm (G) and 6.3 mm (GRC) in terms of mean RMS values and 2.1 mm (G) and 1.9 mm (GRCE) in terms of minimum RMS values, respectively, thereby showing an improvement in scheme 4 over scheme 3 by 1.3–85.6% with average increasing rates of 22.1% (GRCE), 21.9% (GRC), 18.4% (GR), 15.9% (GC), 15.2% (GE), and 12.1% (G). Similar results can be observed for the positioning solution, especially in the height component. These findings clearly show the advantage of the proposed method, which is consistent with the theoretical analysis. Notably, the advantage of the adaptive VCE becomes significant with the inclusion of additional satellite systems.

Characterizing pelvic floor muscles activities using magnetomyography.

To characterize levator ani muscle (LAM) activity in nulligravidas using magnetomyography (MMG) and define MMG characteristics associated with LAM activity with and without accessory muscle contributions. MMG data were collected from eight nulligravidas during rest and voluntary LAM contractions (Kegels) of varying intensity. We utilized simultaneous vaginal manometry and surface electromyography (sEMG) to evaluate for accessory muscle recruitment. Moderate Kegel (MK) MMG trials were sub-selected based on the presence or absence of accessory muscle interaction. Amplitude and spectral-related indicators were calculated across MK epochs: root-mean square (RMS) amplitude, percentage amplitude relative to rest, and relative power spectrum density (rPSD) in three frequency bands (low, middle, high). Ternary diagram characterized rPSD from selected Kegels and ROC analysis was performed to identify cut-points to differentiate MKs from interacting MKs. Nineteen MMG recordings were obtained. Amplitude and spectral parameters were significantly different between isolated and interacting MK epochs. Mean RMS and power values of the isolated MK were, respectively, 120.66 ± 43.8 fT and 1.72 ± 1.44 (T2 /Hz)*10-28 . Amplitudes of MK were 64% and 117 higher than baseline activities for the isolated and interacting epochs, respectively. ROC curves reveled cut-off points on low and middle frequency bands that achieved perfect separation (ROC-AUC = 1.0) between isolated and interacting MK. Our study demonstrates that MMG, a novel biomagnetic technique, allows precise detection and characterization of normal female pelvic floor function. Results show that isolated moderate voluntary contraction of the LAMs produces distinct MMG amplitude and spectral characteristics compared with Kegels involving co-activation of other muscle groups.

Intrinsic and Extrinsic Muscle Function in Rearfoot Strikers During Barefoot and Shod Treadmill Running

Barefoot/minimalist running is theorized to cause an increase in the activity of intrinsic and extrinsic foot muscles. Although studies have shown an increase in the activity of extrinsic foot muscles during barefoot running very little data exists documenting the effects of barefoot running on intrinsic foot muscles. PURPOSE: To compare the activity of select extrinsic and intrinsic muscles during barefoot and shod running in rearfoot strikers. METHODS: A convenience sample of 21 recreational runners were assigned to run both shod and barefoot in a random order. Electrodes were placed on the subjects’ dominant lower extremity over the peroneus longus (PL), tibialis anterior (TA), and abductor halluces (AH) muscles. Subjects participated in a treadmill running protocol consisting of running at 8.0 and 9.7 kph while lower extremity kinematics and electromyographic (EMG) activity of the muscles were recorded using an 8 camera motion analysis system in both footwear conditions. The EMG data were filtered with a fourth order, band pass filter with 10 and 350 Hz cutoffs. Using a 250 ms window, the root mean square (RMS) of the filtered data was obtained. The RMS was normalized to the peak EMG activity of the 8.0 kmh barefoot trials. Using the marker displacement data, the stance phases of the amplitude normalized 9.7 kmh trials were extracted. The average RMS value of the PL, TA, and AH during the stance phase of these trials were obtained and grouped according to running speed and muscle. A two factor, fixed effects ANOVA model was used to determine the effect of footwear condition and muscle on the mean RMS values. RESULTS: The mean (± 1 S.E.) amplitude normalize RMS value during the barefoot condition for the TA, PL, and AH was 50 (± 4.7), 109 (± 17.9), and 123 (± 18.4) percent, respectively. During the shod condition the mean (± 1 S.E.) amplitude normalize RMS value for the TA, PL, and AH was 52 (± 6.1), 103 (± 17.3), and 130 (± 16.8). A significant effect was noted only for muscle (p < .001). Both the PL and the AH exhibited significantly greater activity than the TA in both the shod and barefoot conditions. A significant effect of footwear condition was not present (p = .923). CONCLUSIONS: In rearfoot strikers, footwear does not appear to affect the EMG activity of the TA, PL, or AH.

Accuracy and reproducibility of virtual edentulous casts created by laboratory impression scan protocols

Statement of ProblemAlthough computer-aided design and computer-aided manufacturing (CAD-CAM) complete removable dental prostheses (CRDPs) have gained popularity, conventional impressions are still common for CAD-CAM CRDP treatment. These need to be digitized and converted into virtual edentulous casts with a laboratory impression scan protocol during prosthesis fabrication. How this can best be accomplished is unclear. PurposeThe purpose of this in vitro study was to compare the accuracy and reproducibility of virtual edentulous casts created by a dental laboratory laser scanner and a cone beam computed tomography (CBCT) scanner with a digitized master cast. Material and methodsA master cast was digitized as the virtual reference cast. Ten polyvinyl siloxane impressions were made on the master cast and scanned with the dental laboratory laser scanner and CBCT scanner. The impressions were sprayed with antiglare spray and rescanned. Four groups of virtual study casts (N=40) were created from the impression scans. All virtual study casts and the reference cast were registered with surface-matching software, and the root mean square (RMS) values (representation of overall accuracy) and percentage of measurement data points within 1 standard deviation (SD) of mean RMS values (%, representation of overall reproducibility) among the 4 study groups were measured. Additionally, 95 numeric distance differences (representation of accuracy at each region) were measured in 5 distinct regions: the apex of the denture border, 6 mm from denture border, crest of the ridge, palate, and posterior palatal seal. The repeated-measures ANOVA and post hoc test (t grouping) were used to determine statistical differences (α=.05). ResultsThe laboratory scanner group had a significantly larger RMS value (4.0 ±0.3 μm, P<.001) and smaller percentage of measurement data points within 1 SD of mean RMS value (77.5 ±1.0%, P<.001). The RMS values between the CBCT scanner (1.2 ±0.3 μm) and CBCT scanner–spray (1.1 ±0.2 μm) groups were not significantly different (P=.968), and the percentage of measurement data points within 1 SD of mean RMS values (90.1 ±1.1% versus 89.5 ±0.8%) were also not significantly different (P=.662). The numeric distance differences across 5 regions were affected by the scanning protocols (P<.001). The laboratory scanner and laboratory scanner–spray groups had significantly higher numeric distance differences at the apex of the denture border and crest of the ridge regions (P<.001). ConclusionsThe CBCT scanner created more accurate and reproducible virtual edentulous casts, and the antiglare spray only significantly improved the accuracy and reproducibility of virtual edentulous casts created by the dental laboratory laser scanner. The accuracy of the virtual edentulous casts was different across 5 regions and was affected by the scanning protocols.

Functional taping effects on pain and electrical activation in patients with low back pain

Background: Low back pain (LBP) is a high prevalence health problem and it has several treatments available, among them it is the functional taping. Objective: To evaluate the influence of functional taping on the electrical activation of the erector spinae muscle, the degree of pain and the functionality in subjects with LBP. Methods: Twenty female with LBP participated in the study, and were divided in two groups: with and without the use of the functional taping. The electrical activity of the erector spinae muscle was obtained bilaterally by electromyography (EMG). The root mean square (RMS) value of the EMG was calculated for three maximum voluntary contractions (MVC) obtained before and 48 hours after the application of the taping. The RMS value of each MVC was normalized by the mean RMS value of the first test for each group. The visual analog pain scale was used to measure the pain, and the Roland Morris questionnaire to evaluate the functionality. Comparisons between groups (α=5%) were performed using the Mann Whitney test, and intra-group using the Wilcoxon test. Results: There was no decrease in muscular electrical activation, a significant decrease in pain, and an improvement in functionality. Conclusion: The use of functional taping in the lumbar spine promoted positive effects related to pain and functionality.

Analisis Aktivitas Otot Dengan Perbedaan Jenis Kelamin Pada Postur Tangan Menggunakan Surface Electromyography

This study aims to analyze the muscle activity in the upper body of the hand posture. Measurements are made when the workers perform the activities of making pottery in a sitting position. Measurements use surface electromyography and differentiate sex between men and women. The research steps were: (1) worker capture resulted in ten postures, (2) determination of muscle influences, namely: extensor carpi radialis muscle, extensor carpi ulnar muscle, extensor of the wrist muscle, biceps brachii muscle, flexor carpi radialis muscle, and (5) calculate using root mean square (RMS) and RMS value index RMS value and deviation index RMS value of male - higher than women in each muscle and in every posture .

Evaluation of surface characteristics of rotary nickel-titanium instruments produced by different manufacturing methods.

Instrument fracture is a serious concern in endodontic practice. The aim of this study was to investigate the surface quality of new and used rotary nickel-titanium (NiTi) instruments manufactured by the traditional grinding process and twisting methods. Total 16 instruments of two rotary NiTi systems were used in this study. Eight Twisted Files (TF) (SybronEndo, Orange, CA, USA) and 8 Mtwo (VDW, Munich, Germany) instruments were evaluated. New and used of 4 experimental groups were evaluated using an atomic force microscopy (AFM). New and used instruments were analyzed on 3 points along a 3 mm. section at the tip of the instrument. Quantitative measurements according to the topographical deviations were recorded. The data were statistically analyzed with paired samples t-test and independent samples t-test. Mean root mean square (RMS) values for new and used TF 25.06 files were 10.70 ± 2.80 nm and 21.58 ± 6.42 nm, respectively, and the difference between them was statistically significant (P < 0.05). Mean RMS values for new and used Mtwo 25.06 files were 24.16 ± 9.30 nm and 39.15 ± 16.20 nm respectively, the difference between them also was statistically significant (P < 0.05). According to the AFM analysis, instruments produced by twisting method (TF 25.06) had better surface quality than the instruments produced by traditional grinding process (Mtwo 25.06 files).

Assessment of aberrations and visual quality differences between myopic and astigmatic eyes before and after contact lens application.

OBJECTIVE:To evaluate the aberration and visual quality differences between myopic and astigmatic eyes before and after contact lens application by using corneal aberrometer and low- contrast sensitivity chart.METHODS:Eighty eyes of 40 patients were included in this study. Patients were divided into two groups as myopic (40 eyes, n=20) and astigmatic groups (40 eyes, n=20). We used aspheric Balafilcon A (Purevision and Purevision Toric Bausch&Lomb, Rochester, USA) lenses for each group. Corneal aberrations and low-contrast sensitivity values were measured and compared for each patient in both groups.RESULTS:There were no statistically significant differences between myopic and astigmatic groups when we compared low-contrast sensitivity values for both on- and off-eyes. Mean total higher-order aberration (HOA) values for off-eye, were 0.29±0.10 μm, and 0.33±0.10 μm for on-eye in the myopic group, while they were 0.42±0.14 μm in off-eye and 0.37±0.23 μm in on-eye in the astigmatic group. Off-eye mean coma, irregular astigmatism and total higher-order aberration RMS (root-mean-square) values were significantly higher in the astigmatic group compared to the myopic group (p=0.006, p=0.001, p=0.001) but mean on-eye RMS values were not.CONCLUSION:Myopic and astigmatic patients differ in terms of high-order aberrations and these differences cannot be equalized after contact lens application, but visual quality can be improved in both patients by using contact lenses.