scholarly journals Stress relaxation properties of four orthodontic aligner materials: A 24-hour in vitro study

2016 ◽  
Vol 87 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Luca Lombardo ◽  
Elisa Martines ◽  
Valentina Mazzanti ◽  
Angela Arreghini ◽  
Francesco Mollica ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Single Layer ◽  
In Vitro Study ◽  
Constant Load ◽  
Strength Testing ◽  
Stress Release ◽  
Materials Used ◽  
F22 Aligner ◽  
Over Time

ABSTRACT Objective: To investigate the stress release properties of four thermoplastic materials used to make orthodontic aligners when subjected to 24 consecutive hours of deflection. Materials and Methods: Four types of aligner materials (two single and two double layered) were selected. After initial yield strength testing to characterize the materials, each sample was subjected to a constant load for 24 hours in a moist, temperature-regulated environment, and the stress release over time was measured. The test was performed three times on each type of material. Results: All polymers analyzed released a significant amount of stress during the 24-hour period. Stress release was greater during the first 8 hours, reaching a plateau that generally remained constant. The single-layer materials, F22 Aligner polyurethane (Sweden & Martina, Due Carrare, Padova, Italy) and Duran polyethylene terephthalate glycol-modified (SCHEU, Iserlohn, Germany), exhibited the greatest values for both absolute stress and stress decay speed. The double-layer materials, Erkoloc-Pro (Erkodent, Pfalzgrafenweiler, Germany) and Durasoft (SCHEU), exhibited very constant stress release, but at absolute values up to four times lower than the single-layer samples tested. Conclusions: Orthodontic aligner performance is strongly influenced by the material of their construction. Stress release, which may exceed 50% of the initial stress value in the early hours of wear, may cause significant changes in the behavior of the polymers at 24 hours from the application of orthodontic loads, which may influence programmed tooth movement.

scholarly journals COMPARISON OF THE FORCE DETERIORATION OF DIFFERENT ORTHODONTIC ELASTOMERIC MATERIALS IN ARTIFICIAL SALIVA: AN IN VITRO STUDY

2019 ◽  
Vol 1 (1) ◽  
pp. 41-44
Author(s):  
Rajkiran Lokhande ◽  
Tushar Patil ◽  
Avinash Mahamuni ◽  
Krishnakumar Jaju ◽  
Ketan Gore ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Artificial Saliva ◽  
In Vitro Study ◽  
Clinical Aspect ◽  
Elastic Band ◽  
Force Extension ◽  
The Third ◽  
Elastomeric Materials ◽  
Over Time

The orthodontist must be able to choose an elastic band with force-extension characteristics that are most suitable for the particular tooth movement required. From a clinician view it would be mandatory not only to know the clinical aspect of these elastics but also their basic properties, in order to extract the most out of these polymers. Stretching of elastics are thought to be the primary cause of force degradation of orthodontic elastics but there is evidence of increased force degradation of elastics when exposed to various types of substances like artificial saliva, phosphoric acid and citric acid. Orthodontic elastics have received mixed reactions of practitioners as reported by the vendors of orthodontic supplies. The present study is designed to compare the force deterioration of different orthodontic elastomeric materials in artificial saliva medium. There was a force deterioration over time in all materials, being greatest on the seventh day of the experiment, especially more in the chains; From the third to the fourth week there was no noticeable force degradation in either group; By the end of the experiment, modules showed less deterioration of the force compared to the chains and threads. 

scholarly journals Shear Bond Strength of Different Adhesive Materials used for Bonding Orthodontic Brackets : A Comparative in vitro Study

2015 ◽  
Vol 5 (1) ◽  
pp. 22-26
Author(s):  
Muzin Shahi Shaik ◽  
Snigdha Pattanaik ◽  
Sudhakar Pathuri ◽  
Arunachalam Sivakumar
Keyword(s):  
Bond Strength ◽  
Treatment Duration ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Test Group ◽  
In Vitro Study ◽  
Universal Testing ◽  
Materials Used ◽  
Adhesive Materials

Introduction: Bond strength is an important property and determines the amount of force delivered and treatment duration in orthodontics. Many light-cured bonding materials are being used; but it is required to determine the most efficient one withdesired bond strength. Objective: To determine and compare the shear bond strength of three visible light-cured composites (Transbond XT, Heliositand Enlight) and two self-cured composites (Rely-a-bond and Concise). Materials & Method: 100 extracted premolars were collected and randomly divided into 5 test groups of different adhesives. Brackets were bonded to the teeth in each test group with the respective adhesive according to the manufacturer’s instructions. Each specimen was debonded using Universal Testing Machine and the shear bond strength for each specimen was calculated. All the groups were compared by ANOVA one-way test. Results: There were statistically significant differences among the five groups (P<0.05). The shear bond strength of Enlight (13.92 ± 3.92) is similar to Transbond XT (14.30 ± 4.35). Conclusion: Light cure composites showed higher bond strength than self cure composites.

scholarly journals Hydroxyl and calcium ions diffusion from endodontic materials through roots of primary teeth - in vitro study

2005 ◽  
Vol 13 (2) ◽  
pp. 187-192 ◽  
Author(s):  
Ana Cristina Gerent Petry Nunes ◽  
Maria José de Carvalho Rocha
Keyword(s):  
In Vitro Study ◽  
Deciduous Teeth ◽  
Control Group ◽  
Apical Surface ◽  
Working Length ◽  
Group A ◽  
Periapical Healing ◽  
Materials Used ◽  
Spectrometer Data

The purpose of this research was to evaluate the diffusion of calcium (Ca+2) and hydroxyl (OH-) ions from materials with a calcium hydroxide base - Ca(OH)2 through the intact roots of deciduous teeth. This diffusion of ions is important for periapical healing. Forty-six deciduous teeth were selected and instrumented to their working length with #40 files. The teeth were washed during cleaning and shaping with a 1% sodium hypochlorite (NaOCl) solution. The canals were dried with paper points. The teeth were divided into 4 groups based on the sealer type, with 10 specimens in each group. A fifth group of 6 teeth without sealer constituted the control group. The materials used as sealers were: Ca(OH)2 paste associated to propylene glycol (CaPE) thickened at the proportion of 2:1 w/v; UFSC (Federal University of Santa Catarina) paste - a mixture of 0.3g of zinc oxide with 0.3g of Ca(OH)2 with 0.2ml of olive oil 1:1 w/w; Vitapex® and Sealapex®. The coronal access was sealed with a glass ionomer after the root had been filled with each sealer. A one-third apical surface and foramen was hard-pressed with Araldite®. The teeth were stored individually in flasks containing saline solution at 37ºC and 100% humidity. The OH- and Ca+2 ions diffusion levels were determined using a pH meter and an atomic absorption spectrometer. Data were collected at 48 hours and at intervals of 7, 30, 45 and 60 days. Statistical analysis was performed using ANOVA to compare groups. In the pH evaluation, the CaPE group presented the largest OH- ions diffusion, which peaked at sixty days (p=0.0309), when compared to the other groups (p<0.0001). In relation to amount of Ca+2 ions released, the CaPE paste showed the best results, followed by the UFSC's paste. These results suggest that the CaPE paste was the material that allowed the highest diffusion of OH- and Ca+2 ions.

scholarly journals Evaluation of Sealing Materials Adhesion to Enamel An in vitro study

2017 ◽  
Vol 54 (1) ◽  
pp. 129-132
Author(s):  
Andreea Simona Pop ◽  
Radu Septimiu Campian ◽  
Mariana Pacurar ◽  
Elina Teodorescu ◽  
Olimpia Bunta ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Specific Method ◽  
High Concentration ◽  
Posterior Teeth ◽  
Inorganic Particles ◽  
Material Homogeneity ◽  
Materials Used ◽  
High Degree ◽  
Pits And Fissures

Sealing the pits and fissures of posterior teeth represents a local and specific method of caries prevention. The aim of this study was to evaluate the adhesion of two materials used in sealing pits and fissures: Pitt and Fisure and Fissurit FX (Voco), with the help of the scanning electronic microscope (SEM). The results of the study revealed a much higher quality of the Fissurit FX (Voco) product both in terms of adhesion to the enamel and material homogeneity. The Pitt and Fisure product showed a high degree of detachment from the enamel, marginal infiltration, large particles and a high concentration of inorganic particles.

Flexural strength and surface microhardness of materials used for temporary dental disocclusion submitted to thermal cycling: An in vitro study

2020 ◽  
Vol 18 (3) ◽  
pp. 519-527
Author(s):  
Tamires Borges de Lima ◽  
José Guilherme Neves ◽  
Ana Paula Terossi de Godoi ◽  
Ana Rosa Costa ◽  
Viviane Veroni Degan ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Thermal Cycling ◽  
In Vitro Study ◽  
Vitro Study ◽  
Surface Microhardness ◽  
Materials Used

scholarly journals Evaluation of Dissolving Effect of Chloroform on Three Root Canal Sealers: An In Vitro Study

2017 ◽  
Vol 1 ◽  
Author(s):  
Azah Binti Zainal Abidin ◽  
Azmiera Binti A. Rahman ◽  
Kyaw Mya Htun ◽  
Tin Maw
Keyword(s):  
Stainless Steel ◽  
Root Canal ◽  
In Vitro Study ◽  
Root Canal Sealer ◽  
Original Weight ◽  
Bonferroni Test ◽  
The Difference ◽  
Materials Used ◽  
Endodontic Sealers

<p class="AbstractContent"><strong>Objective</strong>: The purpose of this study was to evaluate and compare the dissolving effect of chloroform on AH 26 (resin-based root canal sealer), Endofill (zinc oxide eugenol-based root canal sealer) and Sealapax (calcium hydroxide-based root canal sealer). Many previous literatures have compared the solubility of several solvents towards gutta percha but very few on endodontic sealers.</p><p class="AbstractContent"><strong>Methods</strong>: The materials used in this experiment apart from the three endodontic sealers are 30 standardized stainless-steel rings, microscopic glass slide, chloroform, acetone, and three decimal digital weighing scales. Thirty standardized stainless steel rings 8mm in diameter and 3mm in height were used for the preparation of sealer specimens and were randomly divided into three experimental groups of ten rings each. Each sealer was then mixed in accordance with the manufacturer’s instructions and introduced into the stainless-steel rings and was weighed to obtain the initial weight. Each sealer was weighed again after immersion in chloroform. The amount of sealer lost was the difference between this measurement and the original weight of the sealer. The results were tabulated and analyzed using analysis of variance (ANOVA).</p><p class="AbstractContent"><strong>Results</strong>: The ANOVA test showed that there were significant differences existed between the groups. The post-hoc (Bonferroni) test showed that AH26 had significantly greater dissolution than Sealapex. However, there were no significant differences in dissolution between AH26 vs. Endofill and Sealapex vs. Endofill.</p><p class="AbstractContent"><strong>Conclusion:</strong> According to the methodology proposed and based on the results of this study, it may be concluded that AH26 presented the highest dissolution value.</p>

scholarly journals Effect of Conventional Adhesive Application or Co-Curing Technique on Dentin Bond Strength

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7664
Author(s):  
Josipa Vukelja ◽  
Eva Klarić Sever ◽  
Ivan Sever ◽  
Silvana Jukić Krmek ◽  
Zrinka Tarle
Keyword(s):  
Bond Strength ◽  
In Vitro Study ◽  
Shear Mode ◽  
Significant Difference ◽  
Application Techniques ◽  
Curing Methods ◽  
Materials Used ◽  
Curing Method ◽  
Adhesive Application

The aim of this in vitro study was to assess the effect of two different adhesive application methods on shear dentin bond strength (ISO 29022) using three various adhesive systems. A mid-coronal section of 77 intact third human molars with fully developed apices was made to create flat bonding substrates. The materials used in the study were Excite F (Ivoclar Vivadent), Prime&Bond Universal (Dentsply Sirona) and G-Premio Bond (GC). The application of each adhesion system was performed in two different ways. In the first group, the bonding agent was light cured immediately after the application (conventional method), while in the second group the adhesive and composite were cured concurrently (“co-curing” method). A total of 180 specimens were prepared (3 adhesives × 2 method of application × 30 specimens per experimental group), stored at 37 °C in distilled water and fractured in shear mode after 1 week. Statistical analysis was performed using ANOVA and Weibull statistics. The highest bond strength was obtained for Prime&Bond conventional (21.7 MPa), whilst the lowest bond strength was observed when co-curing was used (particularly, Excite F 12.2 MPa). The results showed a significant difference between conventional and co-curing methods in all materials. According to reliability analysis, the co-curing method diminished bond reliability. Different application techniques exhibit different bond strengths to dentin.

scholarly journals Stability of Alteplase for Catheter-Directed, Ultrasound-Facilitated Thrombolysis

2021 ◽  
Author(s):  
John Fanikos ◽  
Kathleen Marquis ◽  
Leo Francis Buckley ◽  
Lena Kim Tran ◽  
Kevin C McLaughlin ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
High Performance ◽  
In Vitro Study ◽  
Bleeding Risk ◽  
Reversed Phase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rp Hplc ◽  
Catheter Directed Thrombolysis ◽  
Over Time

Introduction Ultrasound-facilitated catheter-directed thrombolysis is used with low-dose alteplase to treat pulmonary embolism. This reduces the bleeding risk that accompanies systemic administration of higher alteplase doses. While studies suggest that alteplase given over 2 to 6 hours is safe and effective, few data exist to support alteplase stability under these conditions. Therefore, we undertook this in vitro study to determine the duration of alteplase stability. Methods Alteplase was prepared in solutions of 8 mg in 100 mL, 6 mg in 150 mL, and 8 mg in 200 mL. Solutions were administered through the EkoSonicTM Endovascular System with and without ultrasound, to simulate administration over 2, 4, and 6 hours. Alteplase was assessed with reversed-phase high-performance liquid chromatography (RP-HPLC). Assays were performed at time 0 and at 30-minute intervals during simulated infusion. An enzyme-linked immunosorbent assay (ELISA) assay was used to measure alteplase concentrations that were at time 0 and at 15-minute intervals during simulated infusion. Results Using RP-HPLC, in the absence of ultrasound, the alteplase concentration remained within 1% of the original concentration through 120, 240, and 360 minutes of infusion. Using RP-HPLC for measurement, alteplase, in the presence of ultrasound, degraded steadily over time to approximately 90%, 80%, and 70% of its original amounts in 120, 240, and 360 minutes, respectively. Alteplase that remained was available for enzymatic activity. Conclusions Alteplase solutions of 0.04 and 0.08 mg/mL degraded steadily over time during simulated ultrasound-facilitated catheter-directed administration. Alteplase that did not degrade remained available for enzymatic activity.

scholarly journals Inter-device reproducibility of transcutaneous bilirubin meters

2020 ◽  
Author(s):  
Alida J. Dam-Vervloet ◽  
Marlijn D. van Erk ◽  
Nina Doorn ◽  
Stefan G. J. Lip ◽  
Nienke A. Timmermans ◽  
...  
Keyword(s):  
Screening Method ◽  
In Vitro Study ◽  
Systematic Evaluation ◽  
Total Serum ◽  
List Type ◽  
Bilirubin Concentration ◽  
Transcutaneous Bilirubin ◽  
Safety Margins ◽  
Over Time

Abstract Background Transcutaneous bilirubinometry is a widely used screening method for neonatal hyperbilirubinemia. Deviation of the transcutaneous bilirubin concentration (TcB) from the total serum bilirubin concentration (TSB) is often ascribed to biological variation between patients, but variations between TcB meters may also have a role. This study aims to provide a systematic evaluation of the inter-device reproducibility of TcB meters. Materials and Methods Thirteen commercially available TcB meters (JM-105 and JM-103) were evaluated in vitro on phantoms that optically mimic neonatal skin. The mimicked TcB was varied within the clinical range (0.5–181.3 μmol/L). Results Absolute differences between TcB meter outcomes increased with the measured TcB, from a difference of 5.0 μmol/L (TcB = 0.5 μmol/L phantom) up to 65.0 μmol/L (TcB = 181.3 μmol/L phantom). Conclusion The inter-device reproducibility of the examined TcB meters is substantial and exceeds the specified accuracy of the device (±25.5 μmol/L), as well as the clinically used TcB safety margins (>50 µmol/L below phototherapy threshold). Healthcare providers should be well aware of this additional uncertainty in the TcB determination, especially when multiple TcB meters are employed in the same clinic. We strongly advise using a single TcB meter per patient to evaluate the TcB over time. Impact Key message: The inter-device reproducibility of TcB meters is substantial and exceeds the clinically used TcB safety margins. What this study adds to existing literature: The inter-device reproducibility of transcutaneous bilirubin (TcB) meters has not been reported in the existing literature. This in vitro study systematically evaluates this inter-device reproducibility. Impact: This study aids in a better interpretation of the measured TcB value from a patient and is of particular importance during patient monitoring when using multiple TcB meters within the same clinical department. We strongly advise using a single TcB meter per patient to evaluate the TcB over time.

Enamel Apperance after Orthodontic Attachment Removal. In vitro SEM analysis

2017 ◽  
Vol 68 (1) ◽  
pp. 125-127
Author(s):  
Alexandrina Muntean ◽  
Anca Stefania Mesaros ◽  
Anca Porumb ◽  
Stanca Cuc ◽  
Marioara Moldovan ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
In Vitro Study ◽  
Sem Analysis ◽  
Point Of View ◽  
Vitro Study ◽  
Enamel Surface ◽  
Surface Appearance ◽  
Adhesive Remnant Index ◽  
Materials Used

The aim of this in vitro study was to assess the enamel surface appearance and Adhesive Remnant Index (ARI) after braces removal. On teeth vestibular surfaces 90 braces were bonded as follows: metallic, ceramics respectively sapphire using as bonding material Opal Seal� (Ultradent, SUA). Teeth were divided in 3 groups (N=30) and stored for 3 months in artificial saliva, tea and Coca-Cola�. For teeth stored in tea and Coca Cola�, ARI express lower values, indicating a risk for enamel injury as fracture occurs at adhesive-enamel interface. From practical point of view, this in vitro study enhance that braces detachment, finishing and polishing are risk manoeuvres for enamel surface. Materials used for collage must present specific properties in order to reduce enamel fracture.

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