scholarly journals Proximal Contact Tightness Between Direct-composite Additions in the Posterior Dentition: An In Vitro Investigation

2012 ◽  
Vol 37 (3) ◽  
pp. 272-280 ◽  
Author(s):  
D Wolff ◽  
P Hahn ◽  
P Ding ◽  
T Maier-Kraus ◽  
C Frese ◽  
...  
Keyword(s):  
Metal Matrix ◽  
Testing Machine ◽  
Molar Tooth ◽  
Reference Analysis ◽  
Time Points ◽  
Universal Testing ◽  
In Vitro Investigation ◽  
Frictional Forces ◽  
Matrix Band

SUMMARY Purpose The aim of the study was to test whether a novel three-step matrix technique for posterior direct-composite additions creates sufficiently strong proximal contacts. Materials and Methods Contact tightness was measured between direct-composite additions and between original teeth on a model. Therefore, the frictional forces required to remove a straight, 0.05-mm-thick, metal matrix band inserted between adjacent teeth and held by a universal testing machine (Zwicki, Zwick GmbH, Ulm, Germany) were recorded. Measurements were taken at three time points to carry out reference analysis: at baseline, after removal of the maxillary right second premolar (tooth #15) to simulate a diastema, and after closure of the diastema by inserting two direct-composite additions with the three-step matrix technique on the maxillary right first premolar (tooth #14) and first molar (tooth #16). Measurements were performed in the maxillary right (first) and left (second) quadrants to document sagittal displacement. Results The original contact tightness values were between 1.65 ± 0.88 N and 3.05 ± 0.60 N in the first quadrant and between 1.23 ± 0.51 N and 2.18 ± 0.43 N in the second quadrant. After removal of tooth 15, values decreased significantly in the first quadrant and insignificantly in the second. After reconstruction, the contact tightness between teeth 14 and 16 was significantly stronger (tighter) (3.20 ± 0.80 N) than the originally measured contact tightness between teeth 14 and 15 (2.86 ± 0.64 N) and teeth 15 and 16 (1.65 ± 0.88 N) (p=0.006 and 0.001, respectively). Conclusions Within the limitations of an in vitro investigation, this study has shown that by using a novel, three-step matrix technique, direct posterior composite additions can form sufficiently tight proximal contacts.

scholarly journals Comparative Evaluation of Frictional forces between different Archwire-bracket Combinations

2014 ◽  
Vol 4 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Vinit Singh ◽  
Swati Acharya ◽  
Satyabrata Patnaik ◽  
Smruti Bhusan Nanda
Keyword(s):  
Stainless Steel ◽  
Tooth Movement ◽  
Testing Machine ◽  
Frictional Resistance ◽  
Nickel Titanium ◽  
Orthodontic Bracket ◽  
Fixed Appliance ◽  
Beta Titanium ◽  
Frictional Forces

Introduction: During sliding mechanics, frictional resistance is an important counterforce to orthodontic tooth movement; whichmust be controlled to allow application of light continuous forces.Objective: To investigate static and kinetic frictional resistance between three orthodontic brackets: ceramic, self-ligating, andstainless steel, and three 0.019×0.025” archwires: stainless steel, nickel-titanium, titanium-molybdenum.Materials & Method: The in vitro study compared the effects of stainless steel, nickel-titanium, and beta-titanium archwires onfrictional forces of three orthodontic bracket systems: ceramic, self-ligating, and stainless steel brackets. All brackets had 0.022”slots, and the wires were 0.019×0.025”. Friction was evaluated in a simulated half-arch fixed appliance on a testing machine. Thestatic and kinetic friction data were analyzed with 1-way analysis of variance (ANOVA) and post-hoc Duncan multiple rangetest.Result: Self-ligating (Damon) brackets generated significantly lower static and kinetic frictional forces than stainless steel (Gemini)and ceramic brackets (Clarity). Among the archwire materials, Beta-titanium showed the maximum amount of frictional forceand stainless steel archwires had the lowest frictional force.Conclusion: The static and kinetic frictional force for stainless steel bracket was lowest in every combination of wire.

scholarly journals In Vitro Frictional Forces Generated by Three Different Ligation Methods

2008 ◽  
Vol 78 (5) ◽  
pp. 917-921 ◽  
Author(s):  
Paola Gandini ◽  
Linda Orsi ◽  
Chiara Bertoncini ◽  
Sarah Massironi ◽  
Lorenzo Franchi
Keyword(s):  
Steel Wire ◽  
Testing Machine ◽  
Low Friction ◽  
Instron Testing Machine ◽  
Resistance To Sliding ◽  
Titanium Wire ◽  
Frictional Forces ◽  
Conventional Bracket ◽  
Wire Resistance

Abstract Objective: To test the hypothesis that there is no difference between the frictional forces produced by a passive self-ligating bracket (SLB) in vitro and a conventional bracket (CB) used with two types of elastomeric ligatures. Materials and Method: The brackets, wires and ligation methods used in vitro were a passive SLB and a CB used with two types of elastomeric ligatures (conventional elastomeric ligature [CEL] and unconventional elastomeric ligatures [UEL]). The bracket ligation systems were tested with two types of wires (0.014″ super elastic nickel titanium wire and 0.019″ × 0.025″ stainless steel wire). Resistance to sliding of the bracket/wire/ligature systems was measured with an experimental model mounted on the crosshead of an Instron testing machine with a 10 N load cell. Each sample was tested 10 consecutive times under a dry state. Results: Frictional forces close to 0 g were recorded in all tests with SLB and in all tests with UEL on CB with both wire types. Resistance to sliding increased significantly (87–177 g) (P < .05) when CEL on CB was used with both wires. Conclusion: UELs may represent a valid alternative to passive SLBs for low-friction biomechanics.

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 Evaluation of friction produced by self-ligating, conventional and Barbosa Versatile brackets

2016 ◽  
Vol 45 (2) ◽  
pp. 71-77 ◽  
Author(s):  
Jurandir Antonio BARBOSA ◽  
Carlos Nelson ELIAS ◽  
Roberta Tarkany BASTING
Keyword(s):  
Testing Machine ◽  
Frictional Resistance ◽  
The Self ◽  
Factorial Anova ◽  
Steel Wires ◽  
Universal Testing ◽  
Conventional Brackets ◽  
Conventional Type ◽  
Bracket Design

Abstract Introduction The Barbosa Versatile bracket design may provide lower frictional force and greater sliding. However, no in vitro studies have shown its sliding mechanisms and frictional resistance, particularly in comparison with other self-ligating or conventional brackets. Objective To compare the frictional resistance among self-ligating brackets (EasyClip/ Aditek, Damon MX/ Ormco and In Ovation R/ GAC); conventional brackets (Balance Roth/ GAC, and Roth Monobloc/ Morelli); and Barbosa Versatile bracket (Barbosa Versatile/ GAC) with different angles and arch wires. Material and method Brackets were tested with the 0.014", 0.018", 0.019"×0.025" and 0.021"×0.025" stainless steel wires, with 0, 5, 10, 15 and 20 degree angulations. Tying was performed with elastomeric ligature for conventional and Barbosa Versatile brackets, or with a built-in clip system of the self-ligating brackets. A universal testing machine was used to obtain sliding strength and friction value readouts between brackets and wires. Result Three-way factorial ANOVA 4×5×6 (brackets × angulation × wire) and Tukey tests showed statistically significant differences for all factors and all interactions (p<0.0001). Static frictional resistance showed a lower rate for Barbosa Versatile bracket and higher rates for Roth Monobloc and Balance brackets. Conclusion The lowest frictional resistance was obtained with the Barbosa Versatile bracket and self-ligating brackets in comparison with the conventional type. Increasing the diameter of the wires increased the frictional resistance. Smaller angles produced less frictional resistance.

Influence of Different Restoration Techniques on Fracture Resistance of Root-filled Teeth: In Vitro Investigation

2018 ◽  
Vol 43 (2) ◽  
pp. 162-169 ◽  
Author(s):  
ME Hshad ◽  
EE Dalkılıç ◽  
GC Ozturk ◽  
I Dogruer ◽  
F Koray
Keyword(s):  
Fracture Strength ◽  
Resin Composite ◽  
Testing Machine ◽  
Compressive Force ◽  
Control Group ◽  
Hybrid Resin ◽  
Flowable Composite ◽  
In Vitro Investigation ◽  
Significant Difference

SUMMARY Objective: The purpose of this study was to determine the fracture strength of endodontically treated mandibular premolar teeth restored with composites and different reinforcement techniques. Methods and Materials: Forty-eight freshly extracted human mandibular premolar teeth were randomly divided into four groups: group IN, group CR, group FRC, and group PRF. Group IN consisted of teeth with intact crowns and served as the control group. In the other three groups, endodontic treatment was performed and standard mesio-occluso-distal (MOD) cavities were prepared. Then cavities were restored with hybrid resin composite only, flowable composite and hybrid resin composite, and Ribbond, flowable composite and hybrid resin composite in groups CR, FRC and PRF, respectively. All of the teeth were subjected to fracture by means of a universal testing machine, and compressive force was applied with a modified stainless-steel ball at a crosshead speed at 0.5 mm/min. Results: The highest values were observed in group IN, while the lowest values were determined in group CR. There was not any statistically significant difference between group CR and group FCR (p&gt;0.05). When groups CR, FCR, and PRF were compared, group PRF showed significantly better fracture strength than did groups CR and FCR (p&lt;0.05). It was determined that there was not any significant difference between group IN and group PRF (p&gt;0.05). Conclusions: Polyethylene ribbon fiber considerably increases the fracture strength of mandibular premolar teeth with MOD cavities restored with composite.

scholarly journals Evaluation of Different in Vitro Testing Methods for Mechanical Properties of Veneer Ceramics/ Евалуација На Тестовите In Vitro За Одредување На Механичките Особини На Порцеланските Маси За Фасетирање

PRILOZI ◽  
2015 ◽  
Vol 36 (1) ◽  
pp. 225-230 ◽  
Author(s):  
Aneta Mijoska ◽  
Mirjana Popovska
Keyword(s):  
Flexural Strength ◽  
Mechanical Characteristics ◽  
Testing Machine ◽  
In Vitro Testing ◽  
Biaxial Test ◽  
Testing Methods ◽  
Dental Ceramic ◽  
Universal Testing ◽  
Biaxial Tests

Abstract Metal-ceramic and all-ceramic prosthetic restorations in the patient mouth are often damaged by esthetic and functional problems that reduce their success and longevity. Аim: To evaluate methods for testing mechanical characteristics of dental ceramics through analysis of different testing methods. Material and methods: Dental ceramic materials are tested with in vivo and in vitro methods for their most important mechanical characteristics: hardness, toughness, flexural strength and abrasion. In vitro testing methods are faster and more efficient, without subjective factors from the patient according to ISO standards. Testing is done with universal testing machines, like Zwick 1445, Universal Testing Machine (Zwick DmbH & Co.KG, Ulm, Germany), Instron 4302 (Instron Corporation, England), MTS Sintech ReNew 1123 or in oral chewing simulators. Results: According to the testing results, flexure strength is one of the most important characteristic of the dental ceramic to be tested, by the uniaxial and biaxial tests. Uniaxial tests three-point and four-point flexure are not most appropriate because the main stress on the lower side of the tested specimens is tension that causes beginning fractures at the places with superficial flow. Uniaxial results for flexural strength are lower than actual force, while with biaxial test defects and flows on the edges of tested specimens are not directly loaded. Conclusion: Biaxial flexural method has advantages over uniaxial because of real strength results, but also for simple shape and preparing of the testing specimens.

scholarly journals Fabrication of Novel Hydrogel with Berberine-Enriched Carboxymethylcellulose and Hyaluronic Acid as an Anti-Inflammatory Barrier Membrane

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Yu-Chih Huang ◽  
Kuen-Yu Huang ◽  
Bing-Yuan Yang ◽  
Chun-Han Ko ◽  
Haw-Ming Huang
Keyword(s):  
Hyaluronic Acid ◽  
Testing Machine ◽  
Clinical Applications ◽  
Postsurgical Complications ◽  
Barrier Membrane ◽  
Universal Testing ◽  
Griess Reaction ◽  
Hydrogel Membrane ◽  
Anti Inflammatory

An antiadhesion barrier membrane is an important biomaterial for protecting tissue from postsurgical complications. However, there is room to improve these membranes. Recently, carboxymethylcellulose (CMC) incorporated with hyaluronic acid (HA) as an antiadhesion barrier membrane and drug delivery system has been reported to provide excellent tissue regeneration and biocompatibility. The aim of this study was to fabricate a novel hydrogel membrane composed of berberine-enriched CMC prepared from bark of theP. amurensetree and HA (PE-CMC/HA). In vitro anti-inflammatory properties were evaluated to determine possible clinical applications. The PE-CMC/HA membranes were fabricated by mixing PE-CMC and HA as a base with the addition of polyvinyl alcohol to form a film. Tensile strength and ultramorphology of the membrane were evaluated using a universal testing machine and scanning electron microscope, respectively. Berberine content of the membrane was confirmed using a UV-Vis spectrophotometer at a wavelength of 260 nm. Anti-inflammatory property of the membrane was measured using a Griess reaction assay. Our results showed that fabricated PE-CMC/HA releases berberine at a concentration of 660 μg/ml while optimal plasticity was obtained at a 30 : 70 PE-CMC/HA ratio. The berberine-enriched PE-CMC/HA had an inhibited 60% of inflammation stimulated by LPS. These results suggest that the PE-CMC/HA membrane fabricated in this study is a useful anti-inflammatory berberine release system.

scholarly journals An In Vitro Evaluation of Frictional Characteristics of Labial and Lingual Self-ligating Brackets with Various Archwire Alloys

2020 ◽  
Vol 54 (3) ◽  
pp. 203-213
Author(s):  
Subrat Kumar Sahany ◽  
G. Sreejith Kumar
Keyword(s):  
Stainless Steel ◽  
Frictional Force ◽  
Testing Machine ◽  
In Vitro Study ◽  
Fixed Appliance ◽  
Conventional Brackets ◽  
Frictional Forces ◽  
Dry And Wet Conditions ◽  
Lingual Brackets

Background: An understanding of bracket slot–archwire interface is imperative for biomechanical effectiveness in orthodontic sliding mechanics and hence the aim of the study is to evaluate frictional properties of lingual self-ligating brackets comparing with conventional lingual and labial self-ligating brackets using three different archwire alloys in various environments. Materials and Methods: This in vitro study compared the frictional force of labial and lingual self-ligating and conventional lingual brackets with stainless steel, TMA, and Cr-Co alloy archwires of 0.017” × 0.025” dimension in dry and wet conditions. Frictional forces were evaluated in a simulated half arch fixed appliance using a testing machine. Static and kinetic friction were measured and analyzed by one-way analysis of variance (ANNOVA) test and post hoc Duncan multiple range test. The effects of brackets and archwires in dry and wet conditions were analyzed by three-way variance (ANNOVA) test. Result: The maximum frictional forces were observed with labial self-ligating brackets followed by lingual conventional brackets and the least by lingual self-ligating brackets. Of all the wires tested, TMA wires had the maximum frictional forces followed by Co-Cr and stainless steel. In both conditions, the values were non-significant with all bracket–wire combinations except with Co-Cr and TMA wires. Conclusions: Varied amount of frictional force was shown by the brackets and wires with highest by labial self-ligating bracket, followed by lingual conventional and lingual self-ligating brackets. TMA wires experienced higher friction followed by Co-Cr and stainless steel with minimum friction.

scholarly journals Effect of Chemical Disinfectant on the Transverse Strength of Heat-polymerized Acrylic Resins Subjected to Mechanical and Chemical Polishing: An in vitro Study

2012 ◽  
Vol 13 (3) ◽  
pp. 389-393
Author(s):  
Deepthi Kalahasti ◽  
Smitha Sharan ◽  
Harish Konde
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Chemical Polishing ◽  
Denture Base ◽  
Transverse Strength ◽  
Acrylic Resins ◽  
Universal Testing ◽  
Chemical Solutions ◽  
Chemical Disinfectant

ABSTRACT Aims To evaluate the effect of chemical disinfectant on the transverse strength of heat-polymerized acrylic resins subjected to mechanical and chemical polishing. Materials and methods A total of 256 rectangular specimens (65 × 10 × 3 mm) 128 per resin (Lucitone-199 and Acralyn-H) were fabricated. One side of each specimen was not polished and the other was either mechanically (n = 96) or chemically (n = 96) polished and immersed for 10, 30 and 60 minutes in 2% alkaline glutaraldehyde. Mechanically polished (n = 32) and chemically polished (n = 32) control specimens were immersed only in distilled water. The transverse strength (N/mm2) was tested for failure in a universal testing machine, at a crosshead speed of 5 mm/min. Data were statistically analyzed using 2-way ANOVA and Student t-test. Results chemical polishing resulted in significantly lower transverse strength values than mechanical polishing. Lucitone- 199 resin demonstrated the highest overall transverse strength for the materials tested. Heat-polymerized acrylic resins either mechanically or chemically polished, did not demonstrate significant changes in transverse strength during immersion in the disinfecting solution tested, regardless of time of immersion. Conclusion Lucitone-199 resin demonstrated the highest overall transverse strength for the materials tested and significantly stronger than Acralyn-H with either type of polishing following immersion in 2% alkaline glutaraldehyde. Clinical significance There is a concern that immersion in chemical solutions often used for cleansing and disinfection of prostheses may undermine the strength and structure of denture base resins. In this study it was observed that, the transverse strength of samples of Lucitone-199 was higher than that of the samples of Acralyn-H. The chances of fracture of the denture made of Lucitone-199 are less than that of dentures made of Acralyn-H. The chemically polished dentures may be more prone to fracture than mechanically polished dentures. How to cite this article Sharan S, Kavitha HR, Konde H, Kalahasti D. Effect of Chemical Disinfectant on the Transverse Strength of Heat-polymerized Acrylic Resins Subjected to Mechanical and Chemical Polishing: An in vitro Study. J Contemp Dent Pract 2012;13(3):389-393.

Fracture Resistance of Implant Abutments Following Abutment Alterations by Milling the Margins: An In Vitro Study

2016 ◽  
Vol 42 (6) ◽  
pp. 464-468 ◽  
Author(s):  
Anuya Patankar ◽  
Mohit Kheur ◽  
Supriya Kheur ◽  
Tabrez Lakha ◽  
Murtuza Burhanpurwala
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Vitro Study ◽  
Maximum Resistance ◽  
Universal Testing ◽  
Implant Abutments ◽  
Implant Abutment ◽  
Different Levels

This in vitro study evaluated the effect of different levels of preparation of an implant abutment on its fracture resistance. The study evaluated abutments that incorporated a platform switch (Myriad Plus Abutments, Morse Taper Connection) and Standard abutments (BioHorizons Standard Abutment, BioHorizons Inc). Each abutment was connected to an appropriate implant and mounted in a self-cured resin base. Based on the abutment preparation depths, 3 groups were created for each abutment type: as manufactured, abutment prepared 1 mm apical to the original margin, and abutment prepared 1.5 mm to the original margin. All the abutments were prepared in a standardized manner to incorporate a 0.5 mm chamfer margin uniformly. All the abutments were torqued to 30 Ncm on their respective implants. They were then subjected to loading until failure in a universal testing machine. Abutments with no preparation showed the maximum resistance to fracture for both groups. As the preparation depth increased, the fracture resistance decreased. The fracture resistance of implant abutment junction decreases as the preparation depth increases.

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