scholarly journals Marginal Adaptation of Implant Prostheses Fabricated by Different Materials in Excessive Crown Height Space Before and After Veneering

2021 ◽  
Author(s):  
Safoura Ghodsi ◽  
Marzieh Alikhasi ◽  
Majid Sahebi ◽  
Vahideh Nazari
Keyword(s):  
Repeated Measures ◽  
Marginal Adaptation ◽  
Crown Height ◽  
Second Molar ◽  
Basic Model ◽  
Nickel Chromium ◽  
Significant Difference ◽  
Before And After ◽  
Marginal Discrepancy ◽  
To Receive

Objectives: This study aimed to investigate the marginal adaptation of implant-supported three-unit fixed restorations fabricated in excessive crown height by various frameworks namely zirconia, nickel-chromium (Ni-Cr) alloy, and Polyetheretherketone (PEEK) before and after veneering. Materials and Methods: A basic model with two implant fixtures was made to receive posterior three-unit fixed partial dentures (second premolar to second molar) in 15 mm crown height. A total of 30 frameworks were fabricated using Ni-Cr, zirconia, and PEEK (n=10). All specimens were veneered and vertical marginal discrepancy was evaluated before and after veneering using a stereomicroscope (×75). The effect of framework material and veneering on marginal discrepancy was evaluated by repeated-measures and one-way ANOVA, and paired t test (α=0.05). Results: There was a significant difference between the groups (P<0.001) before and after veneering. The vertical marginal discrepancy of zirconia frameworks was significantly lower than that of other groups both before and after veneering (P<0.001). Statistical analysis revealed that the veneering process had a significant effect on marginal adaptation (P<0.001). Conclusion: In implant prostheses with excessive crown height, zirconia had the greatest marginal adaptaion significantly, followed by Ni-Cr. Veneering caused a significant increase in marginal discrepancy of all the materials.

Impact of Resin Composite Viscosity and Fill-technique on Internal Gap in Class I Restorations: An OCT Evaluation

2021 ◽  
Author(s):  
KR Kantovitz ◽  
LL Cabral ◽  
NR Carlos ◽  
AZ de Freitas ◽  
DC Peruzzo ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Resin Composite ◽  
Oral Care ◽  
High Viscosity ◽  
Class I ◽  
Low Viscosity ◽  
Significant Difference ◽  
Before And After ◽  
Internal Adaptation ◽  
Internal Gap

SUMMARY The aim of this in vitro study was to quantitatively evaluate the internal gap of resin composites of high-and low-viscosity used in single- and incremental-fill techniques in Class I cavities exposed to thermal cycling (TC) using optical coherence tomography (OCT). Cavities of 4-mm depth and 3-mm diameter were prepared in 36 third molars randomly distributed into four groups, according to viscosity of restorative resin-based composite (high or low viscosity, all from 3M Oral Care) and technique application (bulk or incremental fill) used (n=9): RC, high-viscosity, incremental-fill, resin-based composite (Filtek Z350 XT Universal Restorative); BF, high-viscosity, bulk-fill, resin-based composite (Filtek One Bulk Fill); LRC, low-viscosity, incremental-fill, resin-based composite (Filtek Z350 XT Flowable Universal Restorative); and LBF, low-viscosity, bulk-fill, resin-based composite (Filtek Flowable Restorative). Single Bond Universal Adhesive system (3M Oral Care) was used in all the experimental groups. The incremental-fill technique was used for RC and LRC groups (2-mm increments), and a single-layer technique was used for BF and LBF groups, as recommended by the manufacturer. The internal adaptation of the resin at all dentin walls was evaluated before and after TC (5000 cycles between 5°C and 55°C) using OCT images. Five images of each restored tooth were obtained. Images were analyzed using ImageJ software that measured the entire length of the gaps at the dentin–restoration interface. The length of gaps (μm) was analyzed using two-way repeated measures ANOVA and the Tukey tests (α=0.05). There was a significant interaction between material types and TC (p=0.006), and a significant difference among all material types (p&lt;0.0001), before and after TC (p&lt;0.0001). Increased internal gaps at the dentin–restoration interface were noticed after TC for all groups. RC presented the lowest value of internal gap before and after TC, while LBF showed the highest values of internal gap after TC. In conclusion, TC negatively affected the integrity of internal gap, whereas high-viscosity, incremental-fill, resin-based composite presented better performance in terms of internal adaptation than low-viscosity, bulk-fill materials in Class I cavities.

scholarly journals Load-Application Devices: A Comparative Strain Gauge Analysis

2015 ◽  
Vol 26 (3) ◽  
pp. 258-262 ◽  
Author(s):  
Renato Sussumu Nishioka ◽  
Luis Gustavo Oliveira de Vasconcellos ◽  
Renata Pilli Jóias ◽  
Sigmar de Mello Rode
Keyword(s):  
Strain Gauge ◽  
Repeated Measures ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Load Application ◽  
Chromium Alloy ◽  
Axial Loads ◽  
Nickel Chromium ◽  
Universal Testing ◽  
Significant Difference

In view of the low loading values commonly employed in dentistry, a load-application device (LAD) was developed as option to the universal testing machine (UTM), using strain gauge analysis. The aim of this study was to develop a load-application device (LAD) and compare the LAD with the UTM apparatus under axial and non-axial loads. An external hexagonal implant was inserted into a polyurethane block and one EsthetiCone abutment was connected to the implant. A plastic prosthetic cylinder was screwed onto the abutment and a conical pattern crown was fabricated using acrylic resin. An impression was made and ten identical standard acrylic resin patterns were obtained from the crown impression, which were cast in nickel-chromium alloy (n=10). Four strain gauges were bonded diametrically around the implant. The specimens were subjected to central (C) and lateral (L) axial loads of 30 kgf, on both devices: G1: LAD/C; G2: LAD/L; G3: UTM/C; G4: UTM/L. The data (με) were statistically analyzed by repeated measures ANOVA and Tukey's test (p<0.05). No statistically significant difference was found between the UTM and LAD devices, regardless of the type of load. It was concluded that the LAD is a reliable alternative, which induces microstrains to implants similar to those obtained with the UTM.

Postural control and risk of falling in people who are blind: The effect and durability of perturbation and vestibular exercises

2022 ◽  
pp. 026461962110673
Author(s):  
Yousof Moghadas Tabrizi ◽  
Mohammad Hani Mansori ◽  
Mohammad Karimizadeh Ardakani
Keyword(s):  
Repeated Measures ◽  
Dynamic Balance ◽  
Somatosensory System ◽  
Exercise Group ◽  
Risk Of Falling ◽  
Balance System ◽  
Significant Difference ◽  
Before And After ◽  
Post Test ◽  
Falling Risk

The aim of this study was to compare the effect and durability of perturbation and vestibular exercises on balance and the risk of falling in people with visual impairment (VI). Thirty-six men with VI were divided into three groups, including a control and two experimental (perturbation and vestibular) groups. The experimental groups performed perturbation and vestibular exercises for 4 weeks and three sessions per week. Biodex balance system was used to assess balance and falling risk before and after training interventions. To evaluate the effects within and between groups at three levels of measurement: pre-test, post-test, and durability effect between three groups, repeated measures analysis of variance (ANOVA) and one-way ANOVA were used. Repeated measures ANOVA test showed that both experimental groups showed significant improvements in static balance, dynamic balance, and falling risk. In comparison between the groups, the results showed that in the post-test and durability stages, there was a significant difference between the groups and the perturbation exercise group had a greater effect on the dependent variables. Due to the effectiveness of exercises, it is recommended that people with VI pay attention to balance-based perturbation exercises to strengthen the somatosensory system and vestibular exercises to strengthen the vestibular system.

scholarly journals Hearing Thresholds Changes after MRI 1.5T of Head and Neck

2019 ◽  
Vol 2019 ◽  
pp. 1-4 ◽  
Author(s):  
Maryam Bahaloo ◽  
Mohammad Hossein Davari ◽  
Mohammad Sobhan ◽  
Seyyed Jalil Mirmohammadi ◽  
Mohammad Taghi Jalalian ◽  
...  
Keyword(s):  
Head And Neck ◽  
High Frequency ◽  
Repeated Measures ◽  
Hearing Threshold ◽  
Significant Shift ◽  
Auditory Thresholds ◽  
Hearing Thresholds ◽  
High Frequency Audiometry ◽  
Significant Difference ◽  
Before And After

Introduction. Exposure to high intensity noise produced by MRI is a cause for concern. This study was conducted to determine the temporary and permanent effects of exposure to noise created by performing MRI on the hearing threshold of the subjects using conventional and extended high frequency audiometry. Methods. This semiexperimental study was performed on 35 patients referred to Shahid Rahnemoun Hospital for head and neck MRI due to different clinical conditions. The hearing threshold of patients was measured before, immediately after, and 24 hours after performing 1.5 Tesla MRI using conventional and extended high frequency audiometry. SPSS version 18 was used to compare the mean hearing thresholds before and after MRI using paired T test and repeated measures analysis. Results. Comparison of auditory thresholds in conventional and extended high frequencies before and immediately after MRI showed a significant shift at 4 KHz (P = 0.008 and P = 0.08 for right and left ears), 6 KHz (P = 0.03 and P = 0.01 for right and left ears), and 14 KHz (P =0.03 and P = 0.31 for right and left ears). However, there was no significant difference between audiometric thresholds before and 24 hours after MRI. Conclusion. Noise due to 1.5 Tesla MRI can only cause transient threshold shift.

scholarly journals The influence of different screw tightening forces on the vertical misfit of implant-supported frameworks

2005 ◽  
Vol 13 (2) ◽  
pp. 120-125 ◽  
Author(s):  
Diego Klee de Vasconcellos ◽  
Marco Antonio Bottino ◽  
Renato Sussumu Nishioka ◽  
Luiz Felipe Valandro ◽  
Elza Maria Valadares da Costa
Keyword(s):  
Repeated Measures ◽  
In Vitro Study ◽  
Pairwise Comparisons ◽  
Tukey Test ◽  
Nickel Chromium ◽  
Marginal Discrepancy ◽  
The Mean ◽  
Post Hoc ◽  
One Way Anova

OBJECTIVES: The present in vitro study was designed to compare the differences in the vertical misfit of implant-supported frameworks using three different forces for tightening the bridge locking screws: fastening by hand until first resistance, and using torque drivers with 10 and 20Ncm. METHODS: The investigation was conducted based on the results given by 9 six-unit nickel-chromium (2 abutments/ 4 pontics) screw-retained implant-supported frameworks. The structures were exposed to simulated porcelain firings. The marginal misfit measurements were made using a traveling measuring microscope at selected screw tightening forces: fastening by hand until first resistance, and using torque drivers with 10 and 20Ncm. The results were submitted to one-way ANOVA with repeated measures on one factor, and post hoc pairwise comparisons using Tukey test (5%). RESULTS: The mean marginal misfit of the frameworks, fastening the screws by hand until first resistance, was 41.56µm (SD±12.45µm). The use of torque driver devices caused a significant reduction in marginal opening (p<0.05). With the lowest torque available (10Ncm), the mean marginal discrepancy at the abutment-framework interface was reduced an average of 52% to a mean marginal opening of 19.71µm (SD±2.97µm). After the use of the 20Ncm torque driver, the mean marginal discrepancy of the frameworks was reduced an average of 69% to a mean marginal opening of 12.82µm (SD±4.0µm). Comparing the use of torque drivers with 10 and 20 Ncm torque, the means are not significantly different from one another. CONCLUSION: The seating force has an important effect on the vertical misfit measurements, once it may considerably narrow the vertical misfit gaps at the abutment-framework interface, thus leading to a misjudgment of the real marginal situation.

Marginal Adaptation of Direct Class II Composite Restorations with Different Cavity Liners

2013 ◽  
Vol 38 (6) ◽  
pp. E210-E220 ◽  
Author(s):  
R Pecie ◽  
I Onisor ◽  
I Krejci ◽  
T Bortolotto
Keyword(s):  
Elastic Modulus ◽  
Class Ii ◽  
Control Group ◽  
Shrinkage Stress ◽  
Marginal Adaptation ◽  
Composite Restorations ◽  
Significant Difference ◽  
Before And After ◽  
Group A ◽  
Group D

SUMMARY The aim of this study was to evaluate how cavity linings with different elastic modulus can influence the marginal adaptation (MA) of Class II composite restorations before and after thermo-mechanical loading. Materials and Methods: Forty Class II cavities with margins extending 1 mm below the cement-enamel junction were prepared in extracted human third molars. In each group except the control group, a lining material of 1-mm thickness was applied to the bottom of the cavity and polymerized before placing the resin composite Herculite XRV Ultra (group A: control; group B: Premise Flowable lining; group C: Herculite XRV Ultra lining; and group D: Optibond FL lining). MA was evaluated (with a scanning electron microscope) before and after loading (200,000 loading cycles). Statistical analysis was done using the Shapiro-Wilks test, the analysis of variance test, and Duncan post hoc test at p&lt;0.05. Results: Before loading, the percentages of continuous margins in dentin were superior (p&lt;0.05) for groups C and D (71.1% and 87.2%, respectively) compared to groups A and B (55.7% and 48.3%, respectively). After loading, group D (79.8%) was statistically superior in dentin compared to all of the other groups (43.6%, 35.9%, and 54.4%, respectively). In occlusal enamel, no significant difference was found between groups. The percentage of enamel fractures and the percentage of noncontinuous margins in proximal enamel were high, with no significant difference between liners. It can be concluded that for the materials used in this study, a 1-mm-thick lining with an extremely low elastic modulus (2-3 GPa) could redistribute shrinkage stress. The use of a flowable composite did not significantly improve MA.

Treatment of Objective and Subjective Benign Paroxysmal Positional Vertigo

2013 ◽  
Vol 24 (07) ◽  
pp. 600-606 ◽  
Author(s):  
Alexandra C. Huebner ◽  
Susan R. Lytle ◽  
Steven M. Doettl ◽  
Patrick N. Plyler ◽  
James T. Thelin
Keyword(s):  
Repeated Measures ◽  
Benign Paroxysmal Positional Vertigo ◽  
Head Position ◽  
Subjective Report ◽  
Repeated Measures Design ◽  
Positional Vertigo ◽  
Data Collection And Analysis ◽  
Significant Difference ◽  
Before And After ◽  
Paroxysmal Positional Vertigo

Background: Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo in adults and is a result of otolithic particles or debris that become free floating within a semicircular canal or adhere to the cupula. Characteristics of BPPV include brief episodes of latent onset vertigo that occur with changes in head position, transient rotary nystagmus beating toward the dependent ear, and reversed nystagmus upon sitting up. Both the vertigo and nystagmus fatigue quickly while maintaining the same head position. The BPPV may be classified as objective or subjective. Objective BPPV presents all the aforementioned symptoms whereas subjective BPPV presents all the symptoms without nystagmus. The accepted method of treatment for objective BPPV is canalith repositioning maneuvers (CRM); however, CRM are not traditionally used as the method of treatment for cases of subjective BPPV. Purpose: The purpose of the study was to determine if the subjective report of dizziness using the Dizziness Handicap Inventory (DHI) was different in patients with objective and subjective BPPV and to determine if the two groups showed similar improvements in perceived dizziness handicap following CRM treatment. Research Design: The present study utilized a retrospective, repeated measures design. Study Sample: Sixty-three adults with BPPV that were given the DHI both before and after CRM treatment. Data Collection and Analysis: Pre and post DHI results were analyzed for participants with objective versus subjective BPPV. A five-question DHI subscale was also analyzed between the groups. Results: A significant difference was noted between initial and posttreatment DHI scores for patients in both the subjective and objective groups when using the full-scale and subscale DHI. No significant difference was noted between groups for their initial or posttreatment DHI scores. The two groups also did not differ significantly in their initial or posttreatment DHI subscale scores. Conclusions: The results of the study indicated that individuals with both objective and subjective BPPV demonstrated significant improvement in DHI scores following CRM treatment. Additionally, there was no difference in DHI improvement for the subjective versus objective group suggesting CRM are effective for both subjective BPPV and objective BPPV. This improvement in DHI scores was also noted in the five-question DHI subscale with no significant difference noted between groups. These findings combined with previous studies suggest the presence or absence of nystagmus during Dix-Hallpike maneuvers is not related to the effectiveness of treatment using CRM.

scholarly journals A Pilot Study on Controlling Coronavirus Disease 2019 (COVID-19) Inflammation Using Melatonin Supplement

2021 ◽  
Author(s):  
Zahra Alizadeh ◽  
Nastaran Keyhanian ◽  
Sara Ghaderkhani ◽  
Simin Dashti-Khavidaki ◽  
Raheleh Shokouhi Shoormasti ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Intervention Group ◽  
Control Group ◽  
Low Light ◽  
Reactive Protein ◽  
Significant Difference ◽  
Before And After ◽  
And Control ◽  
To Receive ◽  
Chest Ct Scan

No effective antiviral drugs and vaccines are available for the treatment of patients with severe coronavirus 2019 (COVID-19). Therefore, available, safe, and inexpensive drugs and supplements such as melatonin are among the proposed options for controlling inflammation. We did a randomized, single-blind study in Imam Khomeini Hospital between June 30, 2020, and August 5, 2020. Mild to moderate COVID-19 patients aged 25-65 years were eligible to enter the study based on chest CT scan, clinical symptoms, and physician diagnosis. The intervention group was prescribed 6 mg of oral melatonin for 2 weeks, which consumed half an hour before bedtime every night in low light conditions. Clinical symptoms and C-reactive protein (CRP) were measured before and after treatment in the melatonin received and control (regular medications) groups. Among screened patients with COVID-19, 14 patients were assigned to receive melatonin, and 17 patients were considered as controls. A significant difference (p=0.005) between CRP 1 and CRP 2 levels (before and after using melatonin) was found in the melatonin group while this difference (p=0.069) was not significant in the control group. Also, the percentage of recovery (based on symptoms) in patients who took melatonin was higher than that of patients in the control group (85.7% VS 47.1%).  The result of this study confirmed the effectiveness of melatonin in mild to moderate outpatients with COVID-19. More clinical trials on elderly, diabetic, obese patients and severe cases are suggested in future studies.   

scholarly journals Stress and Anxiety in Children After the Use of Computerized Dental Anesthesia

2015 ◽  
Vol 26 (3) ◽  
pp. 303-307 ◽  
Author(s):  
Alexandra M. Queiroz ◽  
Ariany B. Carvalho ◽  
Laís L. Censi ◽  
Carmen L. Cardoso ◽  
Christie R. Leite-Panissi ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Numerical Data ◽  
Anxiety State ◽  
Significance Level ◽  
Dental Anesthesia ◽  
Psychological Analysis ◽  
Significant Difference ◽  
Before And After ◽  
Cortisol Levels ◽  
To Receive

The aim of this study was to evaluate the transitory stress levels and the anxiety state in children submitted to conventional and computerized dental anesthesia. Twenty children (7 to 12 years) were randomly assigned to receive conventional and computerized dental anesthesia. To investigate the hypothesis that transitory stress could be lower after using computerized anesthesia compared to conventional anesthesia, cortisol levels in saliva were measured before and after each technique. Anxiety was also evaluated individually by answering the State-Trait Anxiety Inventory for Children (STAIC). Numerical data were analyzed statistically by the Mann-Whitney non-parametric test (5% significance level). Salivary cortisol levels increased in 8 (40%) patients after conventional anesthesia and in 9 (45%) patients after computerized anesthesia, with no statistically significant difference between the two types (p=0.34). In the same way, no statistically significant difference was found between the techniques (p=0.39) related to the psychological analysis based on the STAIC scores. Local anesthesia using either conventional anesthesia or a computerized delivery system produced similar level of stress/anxiety in pediatric patients, using both quantitative and qualitative analyses.

scholarly journals Reaktivní agilita před a po sportovně-specifickém rozcvičení u hráčů stolního tenisu

2015 ◽  
Vol 9 (1) ◽  
pp. 38-44
Author(s):  
Pavel Vacenovský ◽  
Tomáš Vencúrik ◽  
Martin Sebera
Keyword(s):  
Body Weight ◽  
Repeated Measures ◽  
Body Height ◽  
Table Tennis ◽  
Warm Up ◽  
Significant Difference ◽  
Before And After ◽  
Reactive Agility ◽  
National League ◽  
The Difference

The aim of the study was to determine and compare the reactive agility league players and players of regional competitions and its changes due to sport-specific warm-up. The research sample consisted of 43 players, who were divided into two groups. First group consisted of 22 players from teams playing in the national league competitions (24.3 ± 5.6 years, body height 179.4 ± 8 cm, body weight 74.8 ± 10.4 kg), the second group of 21 players playing lower regional competitions (26.7 ± 5.64 years, body height 180.2 ± 7.7 cm, body weight 77.8 ± 10.5 kg). We used Fitro agility test modified for table tennis before and after warm-up. For data analysis was used two-way ANOVA with repeated measures. When comparing reactive agility, we found significant difference before and after the sport-specific warm-up for group of league players (885.94 ± 122.69 ms before the warm-up, 842.80 ± 119.48 ms after the warm-up, an improvement of 4.87 %, p <0.0004) and also for the group of players from lower competitions (932.96 ± 114.78ms before the warm-up, 871.90 ± 119.68 ms after the warm-up, an improvement of 6.54 %, p < 0.0002). Although league players achieved better results, the difference between the groups was found not significant. The nonsignificant statistic values for interaction indicates, that league players did not respond to the sport-specific warm-up differently than players from lower competitions. Sport-specific warm-up is important for improving the reactive agility and therefore should not be underestimated.

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