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 Fracture Resistance of Aged Full-Coverage All-Ceramic Zirconia and Metal-Ceramic Restorations of Implant-Supported Fixed Partial Dentures

2020 ◽  
Vol 8 (D) ◽  
pp. 198-202
Author(s):  
Fariborz Vafaee ◽  
Amirarsalan Hooshyarfard ◽  
Armaghan Shahbazi ◽  
Farnoush Fotovat ◽  
Masoumeh Khoshhal ◽  
...  
Keyword(s):  
Fatigue Fracture ◽  
Fracture Strength ◽  
Fracture Resistance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Full Coverage ◽  
Implant Abutments ◽  
The Difference ◽  
Ceramic Restorations

BACKGROUND: Metal-ceramics restorations were considered a preferable option for fabrication fixed partial dentures (FPDs) that have an acceptable durability, but they are not able to provide the same beauty as the entire ceramic material. Full-contour zirconia, such as Zolid, does not have problems with chipping of layered zirconia, along with translucency and staining capabilities. AIM: This study aimed to assess the fatigue fracture strength of three-unit implant-supported full-contour zirconia and metal-ceramics posterior FPDs. MATERIALS AND METHODS: In this in vitro study, 24 posterior three-unit implant-supported FPDs were fabricated of full-contour zirconia and metal-ceramics and were cemented on implant abutments. To simulate the oral environment, FPDs were subjected to 10,000 thermal cycles between 5 and 55°C for 30 s and were then transferred to a chewing simulator (100,000 cycles, 50 N, 0.5 Hz). Afterward, fatigue fracture strength was measured using a universal testing machine. Data were analyzed using an independent sample t-test. RESULTS: The obtained results showed that the mean and standard deviation of fatigue fracture strength was higher for the metal-ceramics group (2567.8 ± 689.7 N) compared to those for the full-coverage zirconia group (2108.6 ± 455.2 N). However, the difference was not statistically significant (p ˃ 0.05). CONCLUSIONS: Fracture resistance due to fatigue in the metal-ceramics group was not significantly different from full-coverage zirconia group. Full-coverage zirconia seems promising as a metal-ceramics material for the fabrication of posterior three-unit FPDs.

scholarly journals An in-vitro study to evaluate the accuracy of dies obtained from dual arch impression trays using addition silicone impression material and tray combinations

2015 ◽  
Vol 12 (2) ◽  
pp. 111-117
Author(s):  
P K Parajuli ◽  
S George ◽  
V Shenoy
Keyword(s):  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Simultaneous Recording ◽  
T Test ◽  
Impression Material ◽  
Tooth Preparation ◽  
Made In ◽  
Plastic Trays

Background: Dual-arch impression technique allows the simultaneous recording of  tooth preparation, opposing anatomic tooth and maxillomandibular relationship. The  accuracy of reproduction of this easy and quick technique, however, has not been  studied in detail in past. Objective: To compare the accuracy of the impressions  made by using the same impression material in dual arch plastic trays, dual-arch  metal trays and acrylic resin custom trays. Methods: The dies obtained from the  addition silicone impressions made in dual-arch plastic trays, dual-arch metal trays  and full arch acrylic resin custom trays were compared for the dimensional accuracy  with the prepared typodont tooth as a control. Student’s paired t-test and unpaired  t-test were used for the data analyses using the Statistical Package for Social Studies  (SPSS) version 11.5. Results: The dies obtained from all the impression combinations  showed increased dimension (acrylic resin custom trays 9.4 mm±0.048, dual-arch  plastic trays 9.5 mm±0.035, dual-arch metal trays 9.41 mm±0.017) as compared to  the dimension of control (9.39 mm±0.007). Conclusion: All the tray-impression  material combinations showed variable accuracies. Full arch acrylic resin trays  resulted in greatest accuracy whereas dual-arch plastic trays the least accuracy.Health Renaissance 2014;12(2):  pp: 111-117

A Comparative in vitro Study of the Load at Fracture of All-ceramic Crowns with Various Thicknesses of In-Ceram Core

2008 ◽  
Vol 9 (4) ◽  
pp. 17-25 ◽  
Author(s):  
Ilser Turkyilmaz ◽  
Suat Gokce ◽  
Emine Celik-Bagci
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Chromium Alloy ◽  
Dental Practitioners ◽  
Significant Difference ◽  
All Ceramic ◽  
Feasible Option ◽  
Ceramic Crowns

Abstract Aim The aim of this study was to investigate the influence of three different thicknesses of In-Ceram core on the load at fracture of all-ceramic crowns. Methods and Materials Thirty standardized crown-shaped nickel-chromium alloy dies were fabricated using a milling machine. Twenty dies were prepared with a 1 mm shoulder for Groups A and B. The only difference in the ten dies used for Group C was a smaller 0.5 mm lingual shoulder. The thicknesses of In-Ceram were 0.5 mm, 1.5 mm, and 0.75 mm for Groups A, B, and C. All all-ceramic crowns were fabricated in accordance with the manufacturer's instructions. After cementation of the crowns, their fracture resistance was tested with a universal testing machine. The load was directed to a point located 3 mm from the lingual aspect of the incisal edge at 30 degrees to the long axis of each specimen until catastrophic failure occurred. Results The mean loads at fracture for Groups A, B, and C were 1117±388 N, 2083±385 N, and 1439±368 N, respectively. No statistically significant difference in load at fracture between Groups A and C was found (p>0.05). However, the differences were statistically significant between Groups A and B (p<0.001) and Groups B and C (p<0.001). Conclusion Under the guidelines of this study, increasing the thickness of the In-Ceram core increased the fracture resistance of the all-ceramic crowns. Clinical Significance The sufficient thickness of the In-Ceram core of all-ceramic crowns is an important factor in fracture resistance. Therefore, dental practitioners should be careful in patient selection; if the horizontal overlap of a tooth to be restored is too limited, then all-ceramic crowns may not be a feasible option. Citation Gokce S, Celik-Bagci E, Turkyilmaz I. A Comparative in vitro Study of the Load at Fracture of Allceramic Crowns with Various Thicknesses of In-Ceram Core. J Contemp Dent Pract 2008 May; (9)4:017-025.

scholarly journals Fracture Resistance of Primary Molars Restored with Endocrowns Versus Zirconia Crowns (An in Vitro Study)

2021 ◽  
Vol 24 (4) ◽  
Author(s):  
Ayman Sabbah ◽  
Mostafa Kamel
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Composite Resins ◽  
Primary Molars ◽  
P Value ◽  
Pulp Chamber ◽  
Group I ◽  
Zirconia Crowns

Objective: This study aimed to assess the fracture resistance of primary molars restored with endocrowns compared to prefabricated zirconia crowns. Methods: Twelve sound, defect-free primary second molars were selected and divided into two groups: group I included 6 molars restored with zirconia crowns, while group II included 6 teeth restored with endocrowns. For both groups access cavity was prepared for the teeth to open pulp chamber. Fracture resistance of both groups was tested using a universal testing machine. Results: Zirconia crown showed statistically significantly higher mean fracture resistance than Endocrown (P-value = 0.001, Effect size = 2.72). Conclusion: Pulpotomized primary molars restored with Zirconia crowns showed significantly higher mean fracture resistance compared to primary molars restored with endocrowns, meanwhile both restorations have shown higher mean fracture resistance than the maximum biting force in children. Keywords  Composite resins; Endocrown; Fracture strength; Zirconia crowns.

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.

scholarly journals Effect of Incorporation of Disinfectants on Surface Hardness and Dimensional Accuracy of Die Stone: An in vitro Study

2017 ◽  
Vol 7 (3) ◽  
pp. 86-91
Author(s):  
Anubhuti Bakshi ◽  
Rajat Dang
Keyword(s):  
Sodium Hypochlorite ◽  
Testing Machine ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Control Group ◽  
Time Interval ◽  
Type Iv ◽  
Post Hoc

ABSTRACT Aim To evaluate surface hardness and dimensional accuracy of type IV dental stone after incorporation of disinfectants. Materials and methods A total of 100 specimens, 50 (40 mm⨯ 10 mm) disk shaped and 50 frustum cone shaped, were fab- ricated from type IV dental stone after incorporation of various disinfectants, namely glutaraldehyde (2%), iodophor (1.76%), chlorhexidine (2%), and sodium hypochlorite (1%), for evaluation of surface hardness and dimensional accuracy. Surface hardness was tested after 1- and 24-hour time interval using Rockwell hard- ness testing machine. Dimensional accuracy was measured using traveling microscope. Data obtained were compiled and analyzed statistically by using analysis of variance and post hoc test. Results Results showed significant decrease in surface hard- ness of samples incorporated with disinfectants at 1 hour as compared with control (distilled water). Surface hardness of all the samples increased with time and was almost equal to control group at 24-hour interval, with iodophor showing the maximum value in comparison with the other disinfectants used. When dimensional accuracy of all the groups was compared, iodophor and sodium hypochlorite were found to cause negative alterations. Conclusion Within the limitations of this in vitro study, it was concluded that incorporation of disinfectants in die stone during mixing did not affect the hardness value at 24-hour interval. Dimensional accuracy was altered by iodophor and sodium hypochlorite, but remained unaffected by chlorhexidine and glutaraldehyde. How to cite this article Bakshi A, Dang R. Effect of Incorpo- ration of Disinfectants on Surface Hardness and Dimensional Accuracy of Die Stone An in vitro Study. Int J Prosthodont Restor Dent 2017;7(3):86-91.

Fracture Resistance of Endodontically-treated Teeth Restored Using Three Root-reinforcement Methods

2008 ◽  
Vol 9 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Soodabeh Kimyai ◽  
Horieh Moosavi ◽  
Fathemeh Maleknejad
Keyword(s):  
Fracture Resistance ◽  
Resin Composite ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Mean Value ◽  
Resin Cement ◽  
Endodontically Treated Teeth ◽  
Root Reinforcement ◽  
Anterior Teeth

Abstract Aim The aim of this in vitro study was to compare the fracture resistance of endodontically-treated anterior teeth with their roots reinforced using three different restorative methods. Methods and Materials Forty sound maxillary human central incisors were randomly assigned to four groups (n=10). The crowns of the teeth were removed at a level 2 mm incisal to the cementoenamel junction (CEJ). After root canal therapy, flared canals were simulated in three groups. In the first, second, and third groups the flared canals were reinforced with resin composite (RCO) (Clearfil DC Core Automix), two Reforpins (REF), and a resin cement (RCE) (Panavia F 2.0), respectively. In the fourth (DEN) group flared canals were not created. The same size fiber reinforced composite (FRC) posts were cemented with resin cement (Panavia F 2.0) in all groups. After post cementation and restoration of the teeth crown with a core build-up composite (Clearfil Photo Core), the roots of the teeth were embedded in acrylic resin blocks up to 1 mm below the CEJ. The samples were loaded in an Instron testing machine with a crosshead speed of 0.5 mm/min at a 45° angle to the long axis of the tooth on the palatal surfaces until failure occurred. Data were analyzed using the Kruskal-Wallis, Mann-Whitney, and Chi-square tests (p=0.05). Results Significant differences were found between fracture resistance in all of the groups (P<0.05) with the exception being among the RCO and REF groups. The least mean value 230 (130) N and the highest mean value 830 (220) N were shown in the fracture resistance of the RCE and DEN groups, respectively. Conclusion Reforpin can be used as an alternative to resin composite for internal reinforcement of weakened roots according to the results of this study. For reinforcement of flared canals, fiber posts along with Reforpin or resin composite proved to have higher fracture resistance than resin cement. Non flared canals had the highest fracture resistance. Citation Moosavi H, Maleknejad F, Kimyai S. Fracture Resistance of Endodontically-treated Teeth Restored Using Three Root-reinforcement Methods. J Contemp Dent Pract 2008 January; (9)1:030-037.

Comparison of the Effects of Three Different Nickel–titanium Rotary Instruments on the Fracture Resistance of Obturated Roots: An in vitro Study

2017 ◽  
Vol 7 (2) ◽  
pp. 86-90
Author(s):  
Vanitha U Shenoy ◽  
Ritesh B Pawar ◽  
Sumanthini MV ◽  
Saimanaaz AH Shaikh
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Nickel Titanium ◽  
Endodontically Treated Teeth ◽  
Term Survival ◽  
Group I ◽  
Rotary Instruments ◽  
Niti Instruments

ABSTRACT Aim The aim of the article is to compare the effects of three different nickel–titanium (NiTi) rotary instruments on the fracture resistance of obturated roots. Materials and methods A total of 100 permanent mandibular premolars were randomly divided into four groups of 25 teeth each and biomechanical preparation was done: group I: stainless steel K-hand files (HFs), group II: ProTaper NiTi instruments (PT), group III: HyFlex CM NiTi instruments (HCM), and group IV: K3XF NiTi instruments. Following root canal preparation, the canals were obturated using lateral condensation. A light body silicone impression material was used to simulate the periodontal ligament (PDL). Fracture resistance was tested in an Instron testing machine. Statistical analysis Data were analyzed with Kruskal–Wallis test. Results There was no difference in significance (p < 0.05) among the different groups tested with respect to their fracture resistances. Conclusion The present study concluded that rotary instrumentation could result in an increased chance for dentinal defects as compared with hand instrumentation. Greater taper rotary NiTi instruments do not increase the fracture susceptibility of roots, which in turn depends on various factors other than instrumentation alone. Clinical significance Greater taper achieved by rotary NiTi files during canal preparation facilitates efficient irrigation and complete debridement. Root fracture might occur as a result of microcracks or craze lines that propagate with repeated stress application by occlusal forces and also during canal preparation. Based on the results obtained, it can be decided whether the use of the newer rotary NiTi system contributes to endodontic success and long-term survival of endodontically treated teeth. How to cite this article Shaikh SAH, Shenoy VU, Sumanthini MV, Pawar RB. Comparison of the Effects of Three Different Nickel–titanium Rotary Instruments on the Fracture Resistance of Obturated Roots: An in vitro Study. J Contemp Dent 2017;7(2):86-90.

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.

Effect of Metal Extension of Crown in the Screw Access Channel of a Posterior Implant Abutment on the Retention of Cement Retained Prosthesis

2015 ◽  
Vol 41 (5) ◽  
pp. 537-541 ◽  
Author(s):  
Rashmi Biyani ◽  
Mohsin Ali ◽  
Donald Belles ◽  
John M. Powers
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Acrylic Resin ◽  
Instron Testing Machine ◽  
Access Channel ◽  
Significant Difference ◽  
Implant Abutment ◽  
Tensile Forces ◽  
Level Of Significance

Purpose: Reducing the height of the implant abutment due to limited interarch space decreases the surface area for retention of cemented restorations. The purpose of this in vitro study was to see whether engaging the screw access channel with metal extension compensates for the loss of retention of posterior crowns cemented on shorter abutments. Material and Methods: Four identical prefabricated abutments were mounted on implant replicas embedded in acrylic resin blocks. Three of these abutments were reduced in height by 1 mm, 2 mm, and 3 mm respectively and one was left unmodified. Two sets of base metal crowns were fabricated for each abutment, one without and one with the metal extension inside the screw access channel. The crowns were cemented using Tempbond NE. The tensile forces required to separate the cemented crowns from abutments were measured using an Instron testing machine. Statistical analysis of the data was performed using a 2-way analysis of variance and Fisher's protected least significant difference at 0.05 level of significance. Results: An increase of 24% to 261% in retentive forces was observed for the group having metal extension in the screw access channel. Statistically significant differences (P &lt; .001) were found among 2 types of crowns and four heights of abutments. Generally, the retentive forces were reduced in magnitude as the abutment height was reduced. Conclusion: The retention of a casting cemented to posterior implant abutments is influenced by the height of the abutment and the metal extension engaging the screw access channel. The crowns made with a metal extension showed superior retention values.

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