scholarly journals Evaluation of stiffness and plastic deformation of active ceramic self-ligating bracket clips after repetitive opening and closure movements

2015 ◽  
Vol 20 (4) ◽  
pp. 45-50 ◽  
Author(s):  
Grace Kelly Martins Carneiro ◽  
Juliano Alves Roque ◽  
Aguinaldo Silva Garcez Segundo ◽  
Hideo Suzuki
Keyword(s):  
Plastic Deformation ◽  
Testing Machine ◽  
Tensile Tests ◽  
Mean Values ◽  
Custom Made ◽  
Significant Difference ◽  
Before And After ◽  
Instruments And Techniques ◽  
Degree Equation ◽  
Deflection Rate

OBJECTIVE: The aim of this study was to assess whether repetitive opening and closure of self-ligating bracket clips can cause plastic deformation of the clip.METHODS: Three types of active/interactive ceramic self-ligating brackets (n = 20) were tested: In-Ovation C, Quicklear and WOW. A standardized controlled device performed 500 cycles of opening and closure movements of the bracket clip with proper instruments and techniques adapted as recommended by the manufacturer of each bracket type. Two tensile tests, one before and one after the repetitive cycles, were performed to assess the stiffness of the clips. To this end, a custom-made stainless steel 0.40 x 0.40 mm wire was inserted into the bracket slot and adapted to the universal testing machine (EMIC DL2000), after which measurements were recorded. On the loading portion of the loading-unloading curve of clips, the slope fitted a first-degree equation curve to determine the stiffness/deflection rate of the clip.RESULTS: The results of plastic deformation showed no significant difference among bracket types before and after the 500 cycles of opening and closure (p = 0.811). There were significant differences on stiffness among the three types of brackets (p = 0.005). The WOW bracket had higher mean values, whereas Quicklear bracket had lower values, regardless of the opening/closure cycle.CONCLUSION: Repetitive controlled opening and closure movements of the clip did not alter stiffness or cause plastic deformation.

scholarly journals Shear bond strength of novel calcium aluminate-based cement (EndoBinder) to root dentine

2014 ◽  
Vol 08 (04) ◽  
pp. 498-503 ◽  
Author(s):  
Lucas da Fonseca Roberti Garcia ◽  
Hebert Luis Rossetto ◽  
Fernanda de Carvalho Panzeri Pires-de-Souza
Keyword(s):  
Bond Strength ◽  
Calcium Aluminate ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Mineral Trioxide Aggregate ◽  
Acrylic Resin ◽  
Promising Alternative ◽  
Mean Values ◽  
Significant Difference ◽  
Molar Teeth

ABSTRACT Objective: To evaluate the shear bond strength of a novel calcium aluminate-based cement, EndoBinder (EB), to dentine in comparison with Grey and White Mineral Trioxide Aggregate (MTA). Materials and Methods: Root canal hemi-sections obtained from 30 extracted molar teeth were embedded in self-polymerized acrylic resin and were grounded wet in order to obtain a flat dentine surface. Next, the roots were randomly assigned into three groups (n = 10), according to the cement used, as follows: EB: EndoBinder; WMTA: White MTA and GMTA: Grey MTA. The shear bond strength test was performed using a Universal Testing Machine (0.5 mm/min) and the data were submitted to statistical analysis (1-way ANOVA and Tukey tests, P < 0.05). Results: EB presented the highest shear bond strength values; however, there was no statistically significant difference in comparison with GMTA (P > 0.05). WMTA presented the lowest mean values, which were significant in comparison with EB (P < 0.05). Conclusions: The novel calcium aluminate-based cement presented higher shear bond strength than WMTA, and should be considered as a promising alternative in endodontic therapy.

scholarly journals Influence of Apical Patency and Cleaning of the Apical Foramen on Periapical Extrusion in Retreatment

2013 ◽  
Vol 24 (5) ◽  
pp. 482-486 ◽  
Author(s):  
Marili Doro Andrade Deonizio ◽  
Gilson Blitzkow Sydney ◽  
Antonio Batista ◽  
Roberto Pontarolo ◽  
Paulo Ricardo Bittencourt Guimarães ◽  
...  
Keyword(s):  
Material Removal ◽  
Filling Material ◽  
Mean Values ◽  
Filtration System ◽  
Root Canal Retreatment ◽  
Significant Difference ◽  
Before And After ◽  
The Mean ◽  
The Difference ◽  
Removal Technique

This study evaluated the influence of apical patency, root filling removal technique and cleaning of the apical foramen, concerning the amount of debris extruded during root canal retreatment. Forty mandibular incisors were randomly assigned to 4 groups - GIM (n=10), GIIM (n=10), GIPT (n=10) and GIIPT (n=10), which were named according to leaving (I) or not (II) apical patency during canal preparation and filling removal technique (manual - M or ProTaper system - PT). After filling material removal, each specimen of each group had the apical foramen cleaned by sizes 15, 20 and 25 instruments, generating 12 subgroups: GIM15, GIM20, GIM25, GIIM15, GIIM20, GIIM25, GIPT15, GIPT20, GIPT25, GIIPT15, GIIPT20 and GIIPT25. Extruded filling debris was collected by a Milipore filtration system, an HV-durapore, 0.45 µm pore filter with a 25 mm diameter. The filters were weighed before and after the collection on an analytical scale (10–5 g), and the difference was calculated. The mean weight of extruded filling debris was analyzed statistically by Kruskal-Wallis and Friedman ANOVA tests (α=0.05). The mean values found in the groups (in mg) were: GIM (0.95±0.94), GIIM (0.47±0.62), GIPT (0.30±0.31) and GIIPT (0.32±0.44). There was no statistically significant difference among any of the groups or subgroups (p>0.05). ProTaper provided the smallest amount of extruded filling material, regardless of presence or absence of apical patency, followed by manual technique, without and with apical patency. Additional amounts of debris were collected during cleaning of the apical foramen, regardless of the instrument, presence/absence of patency or root filling removal technique.

scholarly journals Effect of whitening dentifrices on the surface roughness of a nanohybrid composite resin

2016 ◽  
Vol 10 (02) ◽  
pp. 170-175 ◽  
Author(s):  
Gabriela Migliorin da Rosa ◽  
Luciana Mendonça da Silva ◽  
Márcio de Menezes ◽  
Hugo Felipe do Vale ◽  
Diego Ferreira Regalado ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Composite Resin ◽  
Wilcoxon Test ◽  
Control Group ◽  
Mean Values ◽  
Short Period ◽  
Significant Difference ◽  
Before And After ◽  
Nanohybrid Composite ◽  
One Way Anova

ABSTRACT Objectives: The present study verified the influence of whitening dentifrices on the surface roughness of a nanohybrid composite resin. Materials and Methods: Thirty-two specimens were prepared with Filtek™ Z350 XT (3M/ESPE) and randomly divided into four groups (n = 08) that were subjected to brushing simulation equivalent to the period of 1 month. The groups assessed were a control group with distilled water (G1), Colgate Total 12 Professional Clean (G2), Sensodyne Extra Whitener Extra Fresh (G3), and Colgate Luminous White (G4). A sequence of 90 cycles was performed for all the samples. The initial roughness of each group was analyzed by the Surface Roughness Tester (TR 200-TIME Group Inc., CA, USA). After the brushing period, the final roughness was measured, and the results were statistically analyzed using nonparametric Kruskal–Wallis and Dunn tests for intergroup roughness comparison in the time factor. For intragroup and “Δ Final − Initial” comparisons, the Wilcoxon test and (one-way) ANOVA were, respectively, performed (α = 0.05). Results: The roughness mean values before and after brushing showed no statistically significant difference when the different dentifrices were used. None of the dentifrices analyzed increased significantly the nanohybrid composite resin surface roughness in a 1 month of tooth brushing simulation. Conclusions: These results suggest that no hazardous effect on the roughness of nanohybrid composite resin can be expected when whitening dentifrices are used for a short period. Similar studies should be conducted to analyze other esthetic composite materials.

scholarly journals Comparative abrasive wear resistance and surface analysis of dental resin-based materials

2018 ◽  
Vol 12 (01) ◽  
pp. 057-066 ◽  
Author(s):  
Maleeha Nayyer ◽  
Shahreen Zahid ◽  
Syed Hammad Hassan ◽  
Salman Aziz Mian ◽  
Sana Mehmood ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Structural Changes ◽  
Wear Testing ◽  
Dental Resin ◽  
Force Microscopy ◽  
Atomic Force ◽  
Custom Made ◽  
Significant Difference ◽  
Before And After ◽  
Roughness Analysis

ABSTRACT Objective: The objective of this study was to assess the surface properties (microhardness and wear resistance) of various composites and compomer materials. In addition, the methodologies used for assessing wear resistance were compared. Materials and Methods: This study was conducted using restorative material (Filtek Z250, Filtek Z350, QuiXfil, SureFil SDR, and Dyract XP) to assess wear resistance. A custom-made toothbrush simulator was employed for wear testing. Before and after wear resistance, structural, surface, and physical properties were assessed using various techniques. Results: Structural changes and mass loss were observed after treatment, whereas no significant difference in terms of microhardness was observed. The correlation between atomic force microscopy (AFM) and profilometer and between wear resistance and filler volume was highly significant. The correlation between wear resistance and microhardness were insignificant. Conclusions: The AFM presented higher precision compared to optical profilometers at a nanoscale level, but both methods can be used in tandem for a more detailed and precise roughness analysis.

scholarly journals Clinical and Hematological Evaluation of Patients with Sickle Cell Anemia Before and After Four Years of Using Hydroxyurea

10.3823/2469 ◽  
2017 ◽  
Vol 10 ◽  
Author(s):  
Ieda Maria Gonçalves Pacce Bispo ◽  
Maria Lúcia Ivo ◽  
Valter Aragão do Nascimento ◽  
Alexandra Maria Almeida Carvalho de Pinto ◽  
Olinda Maria Rodrigues de Araújo ◽  
...  
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Hematological Parameters ◽  
Fetal Hemoglobin ◽  
Hemoglobin Concentration ◽  
Teaching Hospitals ◽  
Acute Chest Syndrome ◽  
Mean Values ◽  
Significant Difference ◽  
Before And After

Objective: Evaluating clinical and hematological-clinical parameters of patients with sickle cell anemia (SCA) before and after four years of using hydroxyurea (HU).  Method: A retrospective cohort study implementing a quantitative, descriptive and analytical approach developed in two public teaching hospitals located in the Central-West region of Brazil, from November 2010 to October 2011. Data collection was performed through medical records of 32 patients with SCA to assess clinical and hematological parameters before and after HU treatment. The study was approved by the UFMS Ethics Committee under protocol number 1890/2010. Results: All of the 32 patients were homozygous with a mean age in the prescription of hydroxyurea of 19.72±7.58 years, an initial dose of 15.59±4.27 mg/kg/day, and 22.48±5.35 mg/kg/day in the fourth year of treatment. Regarding the use of HU, average values of some hematological parameters presented a significant difference in the fourth year compared to the mean values prior to HU use, such as fetal hemoglobin (14.49±7.52%), red blood cells (2.54±0.38x1012/L), hematocrit (25.30±4.03%) and hemoglobin (9.22±3.34g/dL).  Conclusion: Treatment with hydroxyurea showed a significant increase in fetal hemoglobin levels, increased hemoglobin, hematocrit and average corpuscular hemoglobin concentration, with reduced episodes of pain, infection and acute chest syndrome in such a way as to reaffirm its efficiency in treating these patients. Keywords: Hemoglobin; Sickle Cell Anemia; Hydroxyurea.

scholarly journals Evaluation of the Results of Arthroscopic Release in Limits of Movement in Knees

2020 ◽  
Author(s):  
Mohammad Reza Sobhan ◽  
Seyed Hossein Saeed Banadaky ◽  
Mohammad Shafiee ◽  
Mohammad Gheisari
Keyword(s):  
Statistical Tests ◽  
Cross Sectional Study ◽  
Knee Score ◽  
Cross Sectional ◽  
Mean Values ◽  
Arthroscopic Release ◽  
Lysholm Knee Score ◽  
Significant Difference ◽  
Before And After ◽  
The Mean

Introduction: Limits of movement in knees is one of the most common complications following trauma and surgery. With early diagnosis and appropriate treatment choices, knee replacement and performance improvement are expected in many patients. However, limits of movement in knees is unpleasant and should be corrected as soon as possible. In this study, we decided to evaluate the results of arthroscopic release in motion limits of knees. Methods: This was a descriptive cross-sectional study.14 patients who referred to the Shahid Sadoughi Hospital of Yazd from 2014 to 2016 and diagnosed with knee limitation (flexion or extension restriction of more than 10 degrees) were selected. Patients were undergone arthroscopic release and followed-up for 6 months. Lysholm knee score, degrees of flexion and extension, and patient satisfaction were evaluated. The results were analyzed by SPSS-18 and statistical tests Paired T-test as well as Spearman correlation. Results: The mean age of the patients was 28.92±10.99 years. The most common type of trauma in the patients was femoral distal fracture (46.7%). The frequency of the patients' satisfaction with arthroscopy was as followed: 50% (7 patients), had moderate satisfaction, 28.6% (4 ones), high satisfaction, and 21.4% (3 ones) had low satisfaction.The mean difference in Lysholm Knee Score, improvement in degree of extension, improvement in degree of flexion and pain score before and after arthroscopy were 26.21±14.11,64.78±26.13,3.57±2.92 and 4.13±1.65,respectively.There was a significant difference between the mean values of these factors before and after arthroscopy. Conclusion: According to the results obtained, we can conclude that arthroscopic release is an effective and low-complication method in motion limits of knees.

scholarly journals The Effect of Selected Corrective Exercises With Physioball on the Posture of Female Computer Users With Upper Crossed Syndrome

2019 ◽  
Vol 5 (2) ◽  
pp. 112-123
Author(s):  
Fariba Javazi ◽  
◽  
Parisa Sedaghati ◽  
Hasan Daneshmandi ◽  
◽  
...  
Keyword(s):  
Exercise Program ◽  
Exercise Group ◽  
Computer Users ◽  
Mean Values ◽  
Significance Level ◽  
Chest Expansion ◽  
Significant Difference ◽  
Before And After ◽  
Quasi Experimental ◽  
And Control

Objective Upper Crossed Syndrome (UCS) is a type of musculoskeletal system involvement that results in shortening of anterior muscles and weakening of posterior muscles. The aim of this study was to examine the effect of selected corrective exercises with physioball on the postural status of female computer users with UCS. Methods This quasi-experimental study was conducted on 24 female students with UCS who were selected using a purposive sampling method. The subjects were randomly divided into two groups of exercise (n=12) and control (n=12). The exercise group performed exercises for 6 weeks. Photogrammetry method was used to measure the angle of the forward head and round shoulder. A flexible ruler was used to measure the angle of kyphosis, and tape measure was used to measure the chest expansion. These measurements were performed before and after intervention. The collected data were analyzed using paired t-test and ANOVA at the significance level of P<0.05. Results There was a significant difference in mean values of kyphosis (P=0.001), round shoulder (P=0.001), forward head (P=0.002) and chest expansion (P=0.003) before and after exercise. Conclusion Improvement in forward head, round shoulder and thoracic kyphosis angles and chest expansion showed the effectiveness of applied exercise program. Therefore, it is recommended to use this exercise program in computer users with UCS.

scholarly journals Retention Strength after Compressive Cyclic Loading of Five Luting Agents Used in Implant-Supported Prostheses

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Angel Alvarez-Arenal ◽  
Ignacio Gonzalez-Gonzalez ◽  
Hector deLlanos-Lanchares ◽  
Aritza Brizuela-Velasco ◽  
Javier Pinés-Hueso ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Resin Composite ◽  
Testing Machine ◽  
Compressive Load ◽  
Tensile Tests ◽  
Clinical Situation ◽  
Glass Ionomer ◽  
Luting Agents ◽  
Before And After ◽  
Retention Strength

The purpose of this study was to evaluate and compare the retention strength of five cement types commonly used in implant-retained fixed partial dentures, before and after compressive cyclic loading. In five solid abutments screwed to 5 implant analogs, 50 metal Cr-Ni alloy copings were cemented with five luting agents: resin-modified glass ionomer (RmGI), resin composite (RC), glass ionomer (GI), resin urethane-based (RUB), and compomer cement (CC). Two tensile tests were conducted with a universal testing machine, one after the first luting of the copings and the other after 100,000 cycles of 100 N loading at 0.72 Hz. The one way ANOVA test was applied for the statistical analysis using the post hoc Tukey test when required. Before and after applying the compressive load, RmGI and RC cement types showed the greatest retention strength. After compressive loading, RUB cement showed the highest percentage loss of retention (64.45%). GI cement recorded the lowest retention strength (50.35 N) and the resin composite cement recorded the highest (352.02 N). The type of cement influences the retention loss. The clinician should give preference to lower retention strength cement (RUB, CC, and GI) if he envisages any complications and a high retention strength one (RmGI, RC) for a specific clinical situation.

scholarly journals Evaluation and Comparison of Two Different Mouthwashes on Frictional Resistance Between Orthodontic Bracket and Archwire: An in Vitro Study

2019 ◽  
Vol 53 (2) ◽  
pp. 117-125
Author(s):  
Jayanti Choudhary ◽  
B Shashikumar ◽  
Anand K Patil
Keyword(s):  
Stainless Steel ◽  
Artificial Saliva ◽  
Steel Wire ◽  
Testing Machine ◽  
Frictional Resistance ◽  
Control Group ◽  
Tea Tree ◽  
Custom Made ◽  
Significant Difference

Aims: This study aimed to evaluate and compare the effect of tea tree oil (TTO) mouthwash and chlorhexidine (CHX) mouthwash on frictional resistance. Settings and Design: In vitro. Materials and Methods: In total, 60 extracted premolars were mounted on a custom-made acrylic fixture. These 60 premolars were randomly divided into 3 groups of 20 each, on which 0.022″ × 0.028″ slot MBT stainless steel brackets were bonded and 0.019″ × 0.025″ rectangular stainless steel wire was ligated with an elastomeric module. The 3 groups included a control group where the samples were immersed in artificial saliva and 2 experimental groups immersed in 0.2% CHX and TTO mouthwash, respectively, for 1.5 hours. Postimmersion static frictional resistance was evaluated on a universal testing machine at crosshead speed of 0.5 mm/min. Statistical Analysis Used: Tukey’s post hoc procedure. Results: This study showed a statistically significant difference in the frictional resistance between saliva and CHX groups and CHX and TTO groups ( P < .05). No statistically significant difference was observed between saliva and TTO groups ( P > .05). The frictional resistance was more in the CHX mouthwash group than in the TTO mouthwash group. Conclusions: Frictional resistance was lesser in the TTO mouthwash than in the CHX mouthwash. Based on this result, TTO mouthwash can be used instead of CHX mouthwash as an oral hygiene aid in patients with orthodontic treatments.

scholarly journals Analysis of Effectiveness of Amnesty Program as a Response Tool in Containment of the Impact of “Cult Related” Activities in Niger Delta Region

2019 ◽  
pp. 1-16
Author(s):  
Ngozi Rodney Nwaogu ◽  
Vincent Weli ◽  
Mbee Daniel Mbee
Keyword(s):  
Niger Delta ◽  
T Test ◽  
Probability Level ◽  
Delta Region ◽  
Mean Values ◽  
Niger Delta Region ◽  
Significant Difference ◽  
Before And After ◽  
Pearson's Correlation ◽  
The Impact

Background of Study: Cult related activities such as inter and intra cult clashes have been prevalent in communities in Niger Delta Region of Nigeria. The clashes which are violent in nature are carried out by youths who belong to one cult group or the other. The clashes occur when members of a cult group attack members of another or other cult groups or invade a community in order to take control of an area and the proceeds accruing from crude oil exploitation and exploration by multi- national oil companies. Among the major cult groups perpetrating the violent acts include Deybam, Deywell, Iceland and Greenland. Due to the violent clashes many lives have been lost, properties destroyed, women raped, residents displaced, houses burnt and residents kidnapped/abducted. These affected socio-economic activities and livelihood means of the people.  Materials and Methods: This research analyzes the effectiveness of amnesty program as a response tool in mitigating cult related activities in Niger Delta region. Specifically, the study examines the magnitude of cult impact, relationship between frequency of cult attacks and fatalities, and examines the impact of cult activities before and after the amnesty. Adopting Cross- sectional research resign and using data chiefly collected from Nigerian Police, a total of 36 communities were purposively selected from 2 States in Niger Delta where amnesty was offered in 2016. The data were subjected to Pearson’s correlation and T-test statistical analysis. Results: Pearson’s correlation showed that there was a positive significant relationship between cult attacks and fatalities over a ten year period, with r = 0.83 at 99% probability level. The Student’s t-test showed a statistically significant difference on cult attacks before and after amnesty with t-cal of 2.55> t-tab of 2.01 at 95% probability level. The t-test also showed a statistically significant difference on cult fatalities before and after amnesty with t-cal of 2.41> t- tab of 2.01 at 95% probability level. Findings further revealed that mean values of cult attacks (3.20) and fatalities (2.70) after the amnesty were greater than mean values of cult attacks (2.13) and fatalities (1.37) before the amnesty. Conclusion: This showed that despite the amnesty, cult impact was still high in the study area and it was concluded that administration of amnesty is not an effective response tool to mitigation and containment of cult related activities in Niger Delta region, owing to its poor implementation and the desire to join cult groups by many youths who felt that joining the cult group will accord them protection and power over others. It is recommended that government should involve the local communities in designing an intervention program for youths.

Sign in / Sign up

Export Citation Format

Share Document