scholarly journals Mean Shearing Stroke Frequency of Orthodontic Brackets under Cycling Loading: An In Vitro Study

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4280
Author(s):  
Orhan Cicek ◽  
Nurhat Ozkalayci ◽  
Mehmet Yetmez
Keyword(s):  
Bonding Strength ◽  
Orthodontic Brackets ◽  
Stroke Frequency ◽  
Orthodontic Bracket ◽  
Etch And Rinse ◽  
Different Types ◽  
Group 2 ◽  
Cycling Loading ◽  
Shear Bonding Strength ◽  
Group 1

Based on the development of many adhesive systems and bonding techniques, bonding strength of orthodontic brackets has become even more important in modern clinical orthodontics. The aim of this study was to determine mean shearing stroke frequency of different orthodontic bracket types and bonding agents under cycling loading. Therefore, 10 different types of orthodontic bracket from 4 different brands were divided into 2 groups. Two different adhesives, namely Transbond™ XT etch-and-rinse for Group 1 and Transbond™ Plus self-etching-primer adhesive for Group 2 were considered. The brackets were tested under cycling loading force of 10-N and a crosshead speed of 300 mm/min and 40 cycle/min. The frequency of strokes that the brackets failed were determined and these data were analyzed by statistical analysis using an independent sample t-test and one-way analysis of variance (ANOVA). The level of significance was set at p < 0.05. Generally, differences between the frequency of shearing strokes of the bracket failures were found to be statistically significant depending on the type of adhesives and brackets (p < 0.05). The bonding technique for Group 1 was found to have a significantly higher shear bonding strength than Group 2. It is also seen that different types of bracket belonging to the same or different brands had different shear bonding strength. It may be concluded that: (i) all bracket types used in this study can be applied with both bonding techniques, (ii) in order to minimize the risk of hard tissue damage, ceramic brackets should be carefully bonded using the self-etching primary adhesive technique.

Two Adhesive Systems-effect on Adhesion to Tooth Structure

2019 ◽  
Vol 70 (7) ◽  
pp. 2608-2613
Author(s):  
Larisa Simona Deac ◽  
Kamel Earar ◽  
Adela Loredana Colceriu Burtea ◽  
Alexandra Stefania Berghe ◽  
Aurora Antoniac ◽  
...  
Keyword(s):  
Adhesive Systems ◽  
Hybrid Layer ◽  
Tooth Structure ◽  
Selective Etch ◽  
Etch And Rinse ◽  
Significant Difference ◽  
Wisdom Teeth ◽  
Group 2 ◽  
Self Etch ◽  
Group 1

This study evaluates and compares by dye penetration method and SEM photomicrographs the sealing obtained using two different classes of adhesive systems (etch-and-rinse and self-etch with selective etching) with SDR (Dentsply) bulk fill composite. 84 class V cavities were prepared on oral and vestibular face of 42 intact, freshly extracted wisdom teeth. The cavities were randomly divided in two groups and restored: Group 1 with prime &bond one select (Dentsply) and SDR (Dentsply) and Group 2 with prime&bond one Etch&Rinse (Dentsply) and SDR (Dentsply). Prime&bond one Select (Dentsply) is a single component adhesive and can be used in self etch mode, in selective enamel etch mode, or in etch-and-rinse mode. We chosen for this study the selective etch of the enamel mode. Prime&bond one Etch Rinse (Dentsply) is a universal etch-and-rinse one-bottle dental adhesive, designed to be used in two steps. The bulk fill composites are commonly used in modern dentistry due to their properties of low polymerization shrinkage and curing in layer of 4 mm depth, offering the practitioner a fast clinical procedure with good results. The results showed a good sealing at enamel and dentin margins with no statistically significant difference between adhesives, even though the mean of enamel infiltration was smaller for Group1. Furthermore the results show that there were differences between the two groups, for the infiltrations at the enamel, the values of microleakage being arithmetically higher for Group 1, but with no statistically difference between the two groups.SEM images showed for both groups a good adhesion surface with the tooth, but the hybrid layer of the total-etch adhesives is different from the hybrid layer formed by self etch adhesives, in terms of thickness, uniformity. In conclusion both adhesive systems have equivalent sealing qualities and can be successfully used with SDR.

scholarly journals Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets

2017 ◽  
Vol 22 (4) ◽  
pp. 47-52 ◽  
Author(s):  
Marina Cumerlato ◽  
Eduardo Martinelli de Lima ◽  
Leandro Berni Osorio ◽  
Eduardo Gonçalves Mota ◽  
Luciane Macedo de Menezes ◽  
...  
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Surface Treatments ◽  
Orthodontic Brackets ◽  
Positive Correlation ◽  
Diamond Bur ◽  
Group 2 ◽  
Group 1

ABSTRACT Objective: The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT) on the shear bond strength (SBS) of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI). Methods: One-hundred-ninety-two PfT were divided into four groups (n = 48): Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3, two drillings were done with a spherical diamond bur; Group 4, sandblasting was performed with 50-µm aluminum oxide. Before the experiment, half of the samples stayed immersed in distilled water at 37oC for 90 days. Brackets were bonded with Transbond XT and shear strength tests were carried out using a universal testing machine. SBS were compared by surface treatment and by ageing with two-way ANOVA, followed by Tukey’s test. ARI scores were compared between surface treatments with Kruskal-Wallis test followed by Dunn’s test. Results: Surface treatments on PfT enhanced SBS of brackets (p< 0.01), result not observed with ageing (p= 0.45). Groups II, III, and IV showed higher SBS and greater ARI than the Group 1 (p< 0.05). SBS was greater in the groups 3 and 4 (drilling, sandblasting) than in the Group 2 (grinding) (p< 0.05). SBS and ARI showed a positive correlation (Spearman’s R2= 0.57; p< 0.05). Conclusion: Surface treatment on PfT enhanced SBS of brackets, however ageing did not show any relevance. Sandblasting and drilling showed greater SBS than grinding. There was a positive correlation between SBS and ARI.

Comparison of Shear Bonding Strength for Two Different Etching Systems in Canine and Human Dentin

2011 ◽  
Vol 28 (4) ◽  
pp. 236-241
Author(s):  
Larry Kimberlin ◽  
Phil Brown
Keyword(s):  
Bond Strength ◽  
Bonding Strength ◽  
Shear Bond Strength ◽  
Etch And Rinse ◽  
Human Dentin ◽  
Acid Etch ◽  
Molar Teeth ◽  
Bonding Shear Strength ◽  
Composite Cylinders ◽  
Shear Bonding Strength

Canine dentin has increased size and number of dentinal tubules compared to human dentin. With less intertubular surface area for bonding to composite material in dog teeth, bonding shear strength may be affected negatively. This study was designed to compare the shear bonding strength of canine and human dentin. It also compared bond strength of two different acid etch systems when used with the same composite resin. The shear bond strength of composite cylinders to dentin was measured in 30 extracted canine cuspid teeth and a similar number of human molar teeth. Shear bond strength was 40 % greater for human compared with canine dentin. This significantly different (P < 0.05) result validates the hypothesis that dentin bond strength is positively correlated with the area of intertubular dentin. Results also indicated that shear bond strength was greater in the self-etching bond system compared with the etch and rinse system, although this difference was not significant.

scholarly journals Comparative characteristics of the quality of life of asthma patients with different types of airway hyperresponsiveness to physical stimules

2021 ◽  
pp. 55-61
Author(s):  
N. L. Perelman
Keyword(s):  
Quality Of Life ◽  
Airway Hyperresponsiveness ◽  
Group 4 ◽  
Sf 36 ◽  
Different Types ◽  
Asthma Patients ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Aim. To compare the nature and degree of influence of different types of airway hyperresponsiveness (AHR) on the general and specific quality of life (QoL) of patients with asthma and control over the disease.Materials and methods. 234 patients with mild-to-moderate asthma, aged from 18 to 60 years old, were interviewed and examined. Depending on the presence of one or another type of AHR, 4 groups were formed: group 1 included 60 patients with cold AHR, group 2 – 75 patients with hypoosmotic AHR, group 3 – 35 patients with hyperosmotic AHR, group 4 – 64 patients with exercise-induced bronchoconstriction (EIB). QoL and the state of the emotional sphere were assessed using the SF-36, AQLQ, HADS questionnaires. The level of asthma control was determined using the ACT questionnaire. Lung function was assessed by spirometry.Results. When comparing QoL between groups, statistical differences were obtained for most of the SF-36 scales, with the exception of the domains “Role Physical” (RP) and “Bodily Pain” (BP), and their presence and significance varied depending on the types of AHR being compared. The lowest QoL indices were found in group 1 of patients with cold AHR according to the domains “Physical Activity” (PA), RP, BP, and “Role Emotional” (RE). The lowest indices for the domains “General Health” (GH), “Vitality” (V) and “Mental health” (MH) were found in the respondents of the 2nd group. Most of the highest QoL indicators in the compared groups were found in patients of group 4 with EIB in the domains PA, RP, V, RE, and MH. When carrying out a comparative analysis, the maximum number of significant differences was found between the groups with cold AHR and EIB. A comparative study of QoL using a special AQLQ questionnaire showed the lowest indices for the “Activity” and “Symptoms” domains in groups 1 and 2 of asthma patients. In addition, in group 1, the minimum QoL values were recorded for the “General QoL” domain (3.6±0.2 points), and in group 2, for the “Environment” domain (2.9±0.3 compared with 3.9±0.2 points in group 3, p<0.01).Conclusion. This study has demonstrated the multifaceted effect of AHR on health-related QoL, dependent on sensitivity to a particular physical stimulus and the season of maximum trigger action. The subjective assessment of psychosocial functioning is most differentiated according to the GH domain of the SF-36 questionnaire. The greatest negative impact on the QoL indices is exerted by the cold and hypoosmotic AHR, the least – by the EIB. The assessment of QoL allows to get a full picture of the perception of the patient's health level at the moment and in the given conditions.

Methods of Instrument Training and Effects on Pilots’ Performance With Different Types of Flight Instrument Displays

2012 ◽  
Vol 2 (2) ◽  
pp. 62-71 ◽  
Author(s):  
Roneil S. Lindo ◽  
John E. Deaton ◽  
John H. Cain ◽  
Celine Lang
Keyword(s):  
System Approach ◽  
The Other ◽  
Flight Training ◽  
Aircraft Control ◽  
Different Types ◽  
Display Technology ◽  
Group 2 ◽  
Glass Cockpit ◽  
Better Than ◽  
Group 1

As computer display technology has evolved, so have the aircraft instrument displays pilots use for aircraft control and navigation. With the aid of two different flight training devices – one configured with steam gauges and the other configured with glass cockpit – this study measured aircraft control and navigation differences between two pilot groups. Pilot Group 1 had earned their instrument rating in aircraft equipped with steam gauges, and Pilot Group 2 had earned their instrument rating in aircraft equipped with glass cockpits. Using displays for which they were not trained, each pilot was tested on aircraft control and navigation precision. The test required that pilots complete basic instrument maneuvers and an instrument landing system approach. Using MANOVA, deviations from assigned values were recorded and statistically compared. Study findings indicated that steam gauge pilots transitioning to glass cockpits perform better than glass cockpit pilots transitioning to steam gauge displays.

ASSESSMENT OF SHEAR BOND STRENGTH IN DIRECT AND INDIRECT BONDING TECHNIQUES.

2020 ◽  
pp. 11-14
Author(s):  
Sonali Mahadevia ◽  
Bhavya Trivedi ◽  
Arth Patel ◽  
Mauli Shah ◽  
Vaishali Gayakwad
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
T Test ◽  
Orthodontic Brackets ◽  
Indirect Bonding ◽  
Bond Strengths ◽  
Group 2 ◽  
Group 1

Objective: The aim of this study was to assess the shear bond strength of indirectly and directly bonded orthodontic brackets. Ninety Methods: extracted human premolars were collected and divided into two groups. In both the groups, direct bonding (group 1) and indirect bonding (group 2) a light-cured adhesive and primer (ENLIGHT LV) was used. Forty hours after bonding, the samples were De-bonded. Results: Mean shear bond strengths were 12.33, and 12.18 MPA for groups 1, and 2, respectively. The Independent Sample T-Test showed no signicant difference in mean bond strength between groups (P =.667). Conclusion: The result also showed that there was no statistically signicant difference in the shear bond strength between the direct and indirect bonding methods.

Efficacy of two different types of speech therapy for aphasic stroke patients

1989 ◽  
Vol 10 (1) ◽  
pp. 85-123 ◽  
Author(s):  
R. S. Prins ◽  
R. Schoonen ◽  
J. Vermeulen
Keyword(s):  
Speech Therapy ◽  
Therapy Group ◽  
Recovery Process ◽  
Auditory Comprehension ◽  
Language Therapy ◽  
Therapy Program ◽  
Different Types ◽  
Group 2 ◽  
Almost All ◽  
Group 1

ABSTRACTThe influence of two different types of language therapy was investigated by assigning 32 patients to three groups: 10 patients were treated with a Systematic Therapy program for Auditory Comprehension Disorders (group 1), 11 patients received conventional stimulation therapy (group 2), and the other 11 patients received no treatment at all (group 3). Language recovery in the three groups was examined with a test battery consisting of two parts: Part I consisted of 3 subtests for auditory comprehension, which were also used as practice materials in the treatment program given to the patients of group 1; Part II contained 8 tests for auditory comprehension, reading comprehension, and oral expression, the items of which were not used as practice materials in either of the two treated groups. Although the influence of age, time post onset, and severity of the receptive disorder were controlled by multiple regression analysis, it was found that the differences between the three treatment conditions were far from significant on almost all evaluation tests of Part II, as well as on the evaluation tests of Part I. On the basis of these results it was concluded that neither the Systematic Therapy program for Auditory Comprehension Disorders nor the conventional stimulation therapy had any clear effect on the recovery process of the treated patients in groups 1 and 2. Some possible reasons for the failure to demonstrate significant differences in language gains between the three therapeutic conditions are discussed.

scholarly journals Shear Bond Strengths of Different Adhesive Systems to Biodentine

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Mesut Enes Odabaş ◽  
Mehmet Bani ◽  
Resmiye Ebru Tirali
Keyword(s):  
Shear Bond Strength ◽  
Composite Resin ◽  
Adhesive System ◽  
Adhesive Systems ◽  
Time Intervals ◽  
Etch And Rinse ◽  
Bond Strengths ◽  
Group 2 ◽  
Self Etch ◽  
Group 1

The aim of this study was to measure the shear bond strength of different adhesive systems to Biodentine with different time intervals. Eighty specimens of Biodentine were prepared and divided into 8 groups. After 12 minutes, 40 samples were randomly selected and divided into 4 groups of 10 each: group 1: (etch-and-rinse adhesive system) Prime & Bond NT; group 2: (2-step self-etch adhesive system) Clearfil SE Bond; group 3: (1-step self-etch adhesive systems) Clearfil S3Bond; group 4: control (no adhesive). After the application of adhesive systems, composite resin was applied over Biodentine. This procedure was repeated 24 hours after mixing additional 40 samples, respectively. Shear bond strengths were measured using a universal testing machine, and the data were subjected to 1-way analysis of variance and Scheffé post hoc test. No significant differences were found between all of the adhesive groups at the same time intervals (12 minutes and 24 hours) (). Among the two time intervals, the lowest value was obtained for group 1 (etch-and-rinse adhesive) at a 12-minute period, and the highest was obtained for group 2 (two-step self-etch adhesive) at a 24-hour period. The placement of composite resin used with self-etch adhesive systems over Biodentine showed better shear bond strength.

scholarly journals Evaluation of the Efficiency of Three Different Types of Bonded Retainers Used in Orthodontics

2019 ◽  
Vol 70 (8) ◽  
pp. 2769-2776 ◽  
Author(s):  
Luminita Ligia Vaida ◽  
Dana Festila ◽  
Abel Emanuel Moca ◽  
Bianca Ioana Todor ◽  
Bianca Negrutiu ◽  
...  
Keyword(s):  
Relapse Rate ◽  
Laser Sintering ◽  
Dental Arch ◽  
First Year ◽  
Retention System ◽  
Different Types ◽  
Group 3 ◽  
Group 2 ◽  
Bonded Retainers ◽  
Group 1

The bonded retainers are mainly used for the mandibular dental arch. This study aims to analyse the efficiency of three different types of fixed retainers, multistranded 0.0195-in wire, Australian wire and Starbond CoS laser sintering retainer, as well as the relapse rate for each type of retainer used over a period of two years. The sample consisted of 159 patients, of whom 55 patients (Group 1) had multistranded 0.0195-in wire, 53 patients (Group 2) Australian wire, and 51 patients (Group 3) laser-sintering retainers. 16 partial or complete detachments were recorded in the first year of the retention phase, of which 5 retainers from Group 1, 6 from Group 2 and 5 from Group 3, in the case of lasers-sintering retainers only total detachments were noticed, and 2 of the multistranded retainers suffered deformations. The results show that there are no statistically significant differences between the three types of retainers in the first year of retention period, but laser-sintering retainer had a statistically significant better evolution compared to multistranded retainer (p=0.018) after two years of retention. No statistically significant differences were found between the three types of retainers regarding the rate of relapse (10.9% for Group 1, 7.5% for Group 2 and 7.8% for Group 3). In the second year of the retention phase, the relapse rate did not present a statistically significant change from the first year, but it increased slightly in patients from Group 1 and it decreased slightly in patients from Group 3. No fixed retention system is perfect, everything has its drawbacks.

scholarly journals HARNESS FITTINGS OF 7th—6th CENTURIES BC IN THE TRANSCAUCASIA AND THE NEAR EAST

2018 ◽  
Vol 27 (2) ◽  
pp. 35-50
Author(s):  
S. V. Makhortykh
Keyword(s):  
Near East ◽  
Northern Caucasus ◽  
Forest Steppe ◽  
The South ◽  
South Caucasus ◽  
Different Types ◽  
Main Period ◽  
Group 2 ◽  
Group 1

The article is devoted to the analysis of different types of metal and bone harness fittings of VII—VI centuries BC which were found in the South Caucasus and the Near East. Among those fittings, which are constituted about 50 artifacts, two major groups could be distinguished: plain fittings of various geometric shapes and fittings with zoomorphic decorations. The latter group dominates and constitutes about 80 % of the total number of findings. The major regions of distribution of these horse harness attachments are Armenia and Turkey. The cylindrical harness fittings of the first type from the group 1 were the most widespread among the geometrical samples (8 items), while among the zoomorphic ones — claw-shaped, or beak-shaped objects of type 1 from the group 2 (19 items). It should be noted that the majority of the analyzed finds were found not in burial monuments, as in the Northern Caucasus and in the Ukrainian forest-steppe, but at settlements. The emergence of the tradition of manufacturing, as well as the widespread using of various types of harness fittings, and primarily the zoomorphic ones, to the South of the main Caucasian ridge, was the result of the staying and activity on this territory of the Scythians of the South of Eastern Europe. The main period of existence of strap-dividers in Transcaucasia and the Near East was the second half of the VII — the first half of the VI centuries BC.

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