scholarly journals Force decay of polyethylene terephthalate glycol aligner materials during simulation of typical clinical loading/unloading scenarios

2021 ◽  
Author(s):  
Fayez Elkholy ◽  
Silva Schmidt ◽  
Falko Schmidt ◽  
Masoud Amirkhani ◽  
Bernd G. Lapatki
Keyword(s):  
Polyethylene Terephthalate ◽  
Testing Machine ◽  
In Vitro Study ◽  
Bidistilled Water ◽  
Three Point Bending ◽  
Material Stiffness ◽  
Force Decay ◽  
Residual Force ◽  
Loading Modes

Abstract Background This in vitro study investigated the effect of three distinct daily loading/unloading cycles on force delivery during orthodontic aligner therapy. The cycles were applied for 7 days and were designed to reflect typical clinical aligner application scenarios. Materials and methods Flat polyethylene terephthalate glycol (PET-G) specimens (Duran®, Scheu Dental, Iserlohn, Germany) with thicknesses ranging between 0.4 and 0.75 mm were tested in a three-point-bending testing machine. Measurements comprised loading/unloading intervals of 12 h/12 h, 18 h/6 h, and 23 h/1 h, and specimens were exposed to bidistilled water during loading to simulate intraoral conditions. Results A very large decay in force for the PET‑G specimens could already be observed after the first loading period, with significantly different residual force values of 24, 20, and 21% recorded for the 12 h/12 h, 18 h/6 h, and 23 h/1 h loading/unloading modes, respectively (Mann–Whitney U test, p < 0.01). In addition, further decays in force from the first to the last loading period at day 7 of 13.5% (12 h/12 h), 9.7% (18 h/6 h), and 8.4% (23 h/1 h) differed significantly among the three distinct loading modes (Mann–Whitney U test, p < 0.01). Conclusion Although the initial material stiffness of PET‑G is relatively high, the transmission of excessive forces is attenuated by the high material-related force decay already within a few hours after intraoral insertion.

scholarly journals An in vitro comparison of the force decay generated by different commercially available elastomeric chains and NiTi closed coil springs

2007 ◽  
Vol 21 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Ana Cristina Soares Santos ◽  
André Tortamano ◽  
Sandra Regina Frazatto Naccarato ◽  
Gladys Cristina Dominguez-Rodriguez ◽  
Julio Wilson Vigorito
Keyword(s):  
Artificial Saliva ◽  
Testing Machine ◽  
In Vitro Study ◽  
Original Length ◽  
Force Decay ◽  
Decay Pattern ◽  
The Mean ◽  
Initial Force ◽  
Elastomeric Chains

This in vitro study was designed to compare the forces generated by commercially available elastomeric chains and NiTi closed coil springs, and to determine their force decay pattern. Forty elastomeric chains and forty NiTi closed coil springs were divided into 4 groups according to the following manufacturers: (1) Morelli®, (2) Abzil®, (3) TP Orthodontics® and (4) American Orthodontics®. The specimens were extended to twice their original length and stored in artificial saliva at 37°C. Initial force was measured by means of an Instron universal testing machine and then at 1, 4, 7, 14, 21, and 28 days. The results revealed that the elastomeric chains delivered a mean initial force of 347 g for Morelli®, 351 g for American Orthodontics®, 402 g for Abzil®, and 404 g for TP Orthodontics®. The NiTi closed coil springs generated a mean initial force of 196 g for American Orthodontics®, 208 g for TP Orthodontics®, 216 g for Abzil®, and 223 g for Morelli®. The mean percentage of force decay observed after 28 days for the elastomeric chains was 37.4% for TP Orthodontics®, 48.1% for American Orthodontics®, 65.4% for Morelli®, and 71.6% for Abzil®. After 28 days, the NiTi closed coil springs presented a mean percentage of force decay of 22.6% for American Orthodontics®, 29.8% for Abzil®, 30.6% for Morelli®, and 45.8% for TP Orthodontics®. At the end of the study, significant differences were observed between the elastomeric chains and the NiTi closed coil springs. The results indicated that the studied NiTi closed coil springs are more adequate for dental movement than the elastomeric chains.

scholarly journals Comparison of Fracture Resistance in Thermal and Self-Curing Acrylic Resins—An In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Research Work ◽  
Testing Machine ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Thermosetting Resins ◽  
Acrylic Resins ◽  
The Difference

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.

scholarly journals The effect of frog pressure and downward vertical load on hoof wall weight-bearing and third phalanx displacement in the horse - an in vitro study : research communication

2001 ◽  
Vol 72 (4) ◽  
Author(s):  
A. Olivier ◽  
J. Wannenburg ◽  
R.D. Gottschalk ◽  
M.J. Van der Linde ◽  
H.T. Groeneveld
Keyword(s):  
Solar Surface ◽  
Weight Bearing ◽  
Testing Machine ◽  
Vertical Component ◽  
In Vitro Study ◽  
Vitro Study ◽  
Total Weight ◽  
Strain Gauges ◽  
Tensile Testing Machine

A shoe was designed to combine the advantages of a reverse shoe and an adjustable heart bar shoe in the treatment of chronic laminitis. This reverse even frog pressure (REFP) shoe applies pressure uniformly over a large area of the frog solar surface. Pressure is applied vertically upward parallel to the solar surface of the frog and can be increased or decreased as required. Five clinically healthy horses were humanely euthanased and their dismem-bered forelimbs used in an in vitro study. Frog pressure was measured by strain gauges applied to the ground surface of the carrying tab portion of the shoe. A linear variable distance transducer (LVDT) was inserted into a hole drilled in the dorsal hoof wall. The LVDT measured movement of the third phalanx (P3) in a dorsopalmar plane relative to the dorsal hoof wall. The vertical component of hoof wall compression was measured by means of unidirectional strain gauges attached to the toe, quarter and heel of the medial hoof wall of each specimen. The entire limb was mounted vertically in a tensile testing machine and submitted to vertical downward compressive forces of 0 to 2500 Nat a rate of 5 cm/minute. The effects of increasing frog pressure on hoof wall weight-bearing and third phalanx movement within the hoof were determined. Each specimen was tested with the shoe under the following conditions: zero frog pressure; frog pressure used to treat clinical cases of chronic laminitis (7 N-cm); frog pressure clinically painful to the horse as determined prior to euthanasia; frog pressure just alleviating this pain. The specimens were also tested after shoe removal. Total weight-bearing on the hoof wall at zero frog pressure was used as the basis for comparison. Pain-causing and pain-alleviating frog pressures decreased total weight-bearing on the hoof wall (P < 0.05). Frog pressure of 7 N-cm had no statistically significant effect on hoof wall weight-bearing although there was a trend for it to decrease as load increased. Before loading, the pain-causing and pain-alleviating frog pressures resulted in a palmar movement of P3 relative to the dorsal hoof wall compared to the position of P3 at zero frog pressure (P < 0.05). This difference remained statistically significant up to 1300 Nload. At higher loads, the position of P3 did not differ significantly for the different frog pressures applied. It is concluded that increased frog pressure using the REFP shoe decreases total hoof wall weight-bearing and causes palmar movement of P3 at low weight-bearing loads. Without a shoe the toe and quarter hoof wall compression remained more constant and less in magnitude, than with a shoe.

scholarly journals Efficacy of Fiber Post Bonding To Root Dentin after Different Obturation Techniques and Cementation Timings: In Vitro Study

2018 ◽  
Vol 6 (9) ◽  
pp. 1707-1711
Author(s):  
Rami M. Atia ◽  
Nada Omar ◽  
Haidy Nabil ◽  
Yousra Aly
Keyword(s):  
Bond Strength ◽  
Statistical Significance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Resin Cement ◽  
Vitro Study ◽  
Endodontically Treated Teeth ◽  
Root Dentin ◽  
Push Out

OBJECTIVE: The aim of this in vitro study was to assess the effect of obturation technique and cementation timings on the bonding of fibre-reinforced posts to the root canal walls. METHODS: Twenty extracted teeth were randomly allocated to two groups according to the obturation technique and cementation timing. Central incisors with single canals were used after being decoronated. Every extracted tooth of the {vertical compaction group} (VC) group (n = 10) had been obturated using the {E & Q plus obturation system} with posts cemented in the same day; The other (CO) conventional group (n = 10) teeth were obturated using the conventional lateral compaction technique and posts cemented after one week. “SF“ Fiber posts were used after bonding and cementation using Rely X ARC resin cement with all the endodontically treated teeth. The push-out test was performed in a universal testing machine. Data were analysed by 2 way analysis of variance with Statistical significance was set to 0.05. RESULTS: Heat softened gutta percha group showed more push out the bond strength of the bonded posts than the conventional obturation group (p < 0.05). In the middle region, there was no statistical significance between the two groups while there was significance in the coronal and apical thirds. CONCLUSION: The vertical compaction technique and early cementation improved the bond strength of the resin posts in comparison to the conventional obturation technique with late cementation.

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 Effects of Universal Adhesive on Shear Bond Strength of Resin Cement to Zirconia Ceramic with Different Surface Treatments

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Zohreh Moradi ◽  
Farnoosh Akbari ◽  
Sara Valizadeh
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
In Vitro Study ◽  
Surface Treatments ◽  
Resin Cement ◽  
Zirconia Ceramic ◽  
Single Bond ◽  
Universal Adhesive

Aim. This study aimed to assess shear bond strength (SBS) of resin cement to zirconia ceramic with different surface treatments by using Single Bond Universal. Methods. In this in vitro study, 50 zirconia discs (2 × 6 mm) were divided into 5 groups of (I) sandblasting with silica-coated alumina (CoJet)  + silane + Single Bond 2, (II) sandblasting with CoJet + Single Bond Universal, (III) sandblasting with alumina + Single Bond Universal, (IV) sandblasting with alumina + Z-Prime Plus, and (V) Single Bond Universal with no surface treatment. Resin cement was applied in plastic tubes (3 × 5 mm2), and after 10,000 thermal cycles, the SBS was measured by a universal testing machine. The mode of failure was determined under a stereomicroscope at × 40 magnification. Data were analyzed using one-way ANOVA. Results. The maximum (6.56 ± 4.29 MPa) and minimum (1.94 ± 1.96 MPa) SBS values were noted in groups III and I, respectively. Group III had the highest frequency of mixed failure (60%). Group V had the maximum frequency of adhesive failure (100%). Conclusion. Single Bond Universal + sandblasting with alumina or silica-coated alumina particles is an acceptable method to provide a strong SBS between resin cement and zirconia.

scholarly journals COMPARATIVE EVALUATION OF THE SHEAR BOND STRENGTH OF THREE SELF-ETCH DENTIN BONDING AGENTS TO DENTIN: AN IN-VITRO STUDY

2020 ◽  
Vol 8 (10) ◽  
pp. 454-459
Author(s):  
Bhalla V. ◽  
◽  
K. Goud M. ◽  
Chockattu S. ◽  
Khera A ◽  
...  
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Resin Composite ◽  
Testing Machine ◽  
Group Analysis ◽  
In Vitro Study ◽  
Bonding Agents ◽  
Mandibular Molar ◽  
Self Etch

Background:Dentin bonding is an ever-evolving field in adhesive dentistry. With the introduction of newer systems into the market, there is a crucial need to test their efficiency in terms of bond strength. Dual-cured adhesives in theory may provide for a better degree of conversion as compared to conventional light-cured adhesives .Thus, the aim of this study was to compare the shear bond strength of three different self-etch adhesives namely ClearfilSE bond (Kuraray), Tetric N Bond Universal (IvoclarVivadent) and Futura Bond DC (Voco) to dentin. Materials & Methods: Ninety extracted non-carious, intact human mandibular molar teeth were selected for this study. Each tooth was decoronated using a double-sided diamond disc with water coolant to a depth of 2mm from the cusp tip .The cut dentin surface was then abraded against 600-grit wet silicon carbide papers for 60 seconds to produce a uniform smear layer. The root portion of each tooth was mounted on a plastic ring using cold cure acrylic resin. Specimens were then divided into three adhesive groups of 30 teeth each, Group A: ClearfilSE Bond (Kuraray), Group B: Tetric N Bond Universal (IvoclarVivadent), Group C :Futura Bond DC (Voco). All bonding agents were used according to the manufacturers’ instructions, in combination with the resin composite Tetric N Ceram (IvoclarVivadent). The samples were thermocycled, followed by shear bond strength testing using a Universal testing machine (Hounsfield). Data were subjected to statistical analysis using one-way analysis of variance (ANOVA) (P<0.05) and Post hoc Tukey’s test for inter- and intra- group analysis respectively. Results: Clearfil SE Bond yielded the highest shear bond strength values (30.9 ±4.66 MPa) which were statistically significant, followed byTetric N Bond Universal group (29.8 ±4.34) and the lowest shear bond strength values were recorded for Futura Bond DC (18.2 ±3.13). Conclusion: Clearfil SE bond and Tetric N bond Universal can be considered as better options than Futura Bond DC.

scholarly journals A COMPARATIVE EVALUATION OF MICROLEAKAGE, COMPRESSIVE STRENGTH, FLEXURAL STRENGTH AND FLUORIDE RELEASE OF ZIRCONOMER AND KETAC SILVER: AN IN VITRO STUDY.

2020 ◽  
Vol 9 (4) ◽  
Author(s):  
CHARANTEJA VEMAGIRI ◽  
Uloopi KS ◽  
Vinay Chandrappa ◽  
Anusha Ch
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Testing Machine ◽  
In Vitro Study ◽  
Biological Properties ◽  
T Test ◽  
Fluoride Release ◽  
Restorative Material ◽  
Glass Ionomer

Background: A successful restorative material forms a better adhesion, resist the microleakage and releases fluoride. However, existing glass ionomer cements cannot be used as a posterior restorative material in stress bearing areas. A new ionomer called Zirconomer, zirconia reinforced glass ionomer claims to exhibit high physical and biological properties. Aim: To assess and compare the microleakage, compressive strength, flexural strength and fluoride release from zirconomer with ketac silver. Materials & Methods: On twenty caries free premolar teeth (10 per each group), a class v cavity was restored with zirconomer and ketac silver. The microleakage was assessed using dye penetration test and stereomicroscope. The compressive and flexural strengths of these materials were measured using Instron Universal testing machine. The amount of fluoride released from the modified ionomers at pH 5 and pH 7 was estimated using Orion fluoride specific electrode. The obtained data was then subjected to statistical analysis. Results: Data was analysed using paired t-test for intergroup comparisons and unpaired t-test for intragroup comparisons. The overall microleakage (0.5±0.48) of zirconomer was significantly less (p=0.000) compared to ketac silver (1.9±0.83). Zirconomer demonstrated a significant higher compressive strength (330.25±60.14), flexural strength (33.058±2.36) than ketac silver (p= 0.000). Zirconomer demonstrated high fluoride release from day 1 to day 7 at both pH 5 and pH 7. Conclusion: Zirconomer demonstrated better physical and biological properties compared with ketac silver.

Influence of two different desensitizers on the shear bond strength of two newly introduced bonding agents following the total etch strategy: an in vitro study

2020 ◽  
Vol 12 (1) ◽  
pp. 3-10
Author(s):  
Dr. Alok Pandey Pandey ◽  
Dr. Shibani Shetty ◽  
Dr. Jayalakshmi K B ◽  
Dr. PrasannalathaNadig ◽  
Dr. Sujatha I ◽  
...  
Keyword(s):  
Bond Strength ◽  
Testing Machine ◽  
In Vitro Study ◽  
Bonding Agents ◽  
Group 4 ◽  
Multiple Comparison Test ◽  
Desensitizing Agents ◽  
Group 3 ◽  
Machine Analysis

Objective: Evaluate the shear bond strengths of two different dentin bonding agents following the pretreatment of dentine with two different desensitizing agents. Materials and methods: 60 premolar samples were grounded to expose the dentine. The teeth were categorized into three major groups. Each major group was subdivided into 2 subgroups of 10 samples each. Groups 1&2 involved no pretreatment with desensitizer prior to the bonding agents application. Groups 3&4 were pretreated with Gluma desensitizing agent prior to the use of All bond Universal as self-etching modality in group 3 and One Coat 7.0 in group 4. Groups 5&6 involved pretreatment with MS Coat One desensitizer and use of All bond Universal and One Coat7.0 bonding agents respectively. Shear bond testing of the samples were then evaluated by the universal testing machine. Analysis of the data was done using One-way ANOVA and pair-wise comparison was performed using Tukey’s multiple comparison test. Results: Control groups in which no pretreatment was done with any desensitizing agent had the highest bond strength when compared to the experimental groups. Among the desensitizers, significantly higher bond strength was shown by Gluma than MS Coat One. Conclusion: Gluma with One Coat 7.0 can be used to decrease the post-operative sensitivity without compromising bond strength.

scholarly journals “Ormocer an innovative technology”: A replacement for conventional cements and veneer? A comparative in vitro analysis

2017 ◽  
Vol 11 (01) ◽  
pp. 058-063 ◽  
Author(s):  
Vini Rajeev ◽  
Rajeev Arunachalam ◽  
Sanjna Nayar ◽  
P. R. Arunima ◽  
Sivadas Ganapathy ◽  
...  
Keyword(s):  
Bond Strength ◽  
Testing Machine ◽  
In Vitro Study ◽  
Sem Analysis ◽  
Innovative Technology ◽  
Group I ◽  
Luting Cement ◽  
Significant Difference ◽  
Vitro Analysis

ABSTRACT Objective: This in vitro study was designed to assess shear bond strength (SBS) of ormocer flowable (OF) resin as a luting agent, ormocer as an indirect veneer material with portrayal of modes of failures using scanning electron microscope (SEM). Materials and Methods: Sixty maxillary central incisors were divided into Group I, II, and III with 20 samples each based on luting cement used. They were OF, self-adhesive (SA) cement, and total etch (TE) cement. These groups were subdivided into “a” and “b” of ten each based on the type of veneering materials used. Veneer discs were fabricated using Ormocer restorative (O) and pressable ceramic (C). Specimens were thermocycled and loaded under universal testing machine for SBS. The statistical analysis was done using one-way ANOVA post hoc Tukey honest significant difference method. Results: A significant difference was observed between the Groups I and II (P < 0.05). The highest mean bond strength when using ormocer veneer was obtained with the Group Ia (19.11 ± 1.92 Mpa) and lowest by Group IIa (8.1 ± 1.04 Mpa), whereas the highest mean bond strength while using ceramic veneer was of similar range for Group Ib (18.04 ± 4.08 Mpa) and Group IIIb (18.07 ± 1.40 Mpa). SEM analysis revealed OF and TE presented mixed type of failure when compared with SA where failure mode was totally adhesive. Conclusion: OF was found equally efficient like TE. Bond strength of ormocer as a veneer was not inferior to ceramic making it one of the promising additions in the field of dentistry.

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