Comparative analysis of flexural strength of abraded and polished porcelain surfaces – an in vitro study

Typically, prosthodontists adjust ceramic restorations glazed surface by grinding prior to insertion. Such alterations of surfaces are necessary for the correction of occlusal interferences. We aimed to evaluate and compare the change in flexural strength of ceramic surfaces after re-glazing and polishing. This study included 40 samples of ceramic blocks that were fabricated and glazed, and then fired in accordance with the manufacturer’s recommendations. The sample was randomly divided into four groups of 10 samples each. The first group was the control group with unaltered glazed samples. The second group was abraded with an extra-fine diamond bur followed by re-glazing, and the other two groups were polished with two commercially available polishing kits after abrading them with an extra-fine diamond bur. The samples were tested for their flexural strength using a universal testing machine. On the application of the F test on the means of all the groups, a value greater than 0.05 was found, which meant that there is no statistically significant difference in flexural strength values between the groups (P-value>0.05). Since the flexural strength values of the polished group were comparable to the other groups, polishing can be used instead of re-glazing for ceramic restorations. This reduces an additional clinical appointment for the patient and saves working time.

Download Full-text

Effect of Different Time Periods of Vital Bleaching on Flexural Strength of Bovine Enamel and Dentin Complex

The Journal of Contemporary Dental Practice ◽

10.5005/jcdp-8-3-21 ◽

2007 ◽

Vol 8 (3) ◽

pp. 21-28 ◽

Cited By ~ 10

Author(s):

Marjaneh Ghavamnasiri ◽

Sara Abedini LNU ◽

Alireza Mahdizadeh Tazangi

Keyword(s):

Flexural Strength ◽

Artificial Saliva ◽

Testing Machine ◽

Control Group ◽

Mean Values ◽

Significant Difference ◽

Time Periods ◽

Group 2 ◽

Bovine Enamel

Abstract Aim The aim of this in vitro study was to evaluate the effect of 20% carbamide peroxide (CP) on the flexural strength (FS) of bovine enamel and dentin complex. Methods and Materials One hundred sound bovine teeth were selected for use. Blocks (2×3×8 mm) from the middle portion of the facial surfaces of each crown were sectioned from the teeth. The specimens were randomly divided into five groups (n=20) based on the time period of vital bleaching. Group 1 comprised the control group kept in artificial saliva. The experimental groups subjected to immersion in 20% CP, Opalescence, for four, six and eight weeks, respectively (eight hours daily). Mechanical testing was performed 24 hours after the last treatment using an Instron Universal Testing Machine with a crosshead speed of 0.5 mm/min. The results were analyzed by one-way analysis of variance (ANOVA) and Tukey's test (α=0.05). Results Mean values for FS were 141.27, 103.06, 120.71, 130.23, and 117.90 (Mpa), respectively. Statistically significant differences in FS were noted among the groups. A statistically significant difference was observed between Group 2 (two week bleach) and the control. Conclusion Application of 20% CP bleach for two weeks provided significant decreases in FS of bovine enamel and dentin complex. Similar decreases were not observed among the other groups. Citation Ghavamnasiri M, Abedini S, Tazangi AM. Effect of Different Time Periods of Vital Bleaching on Flexural Strength of Bovine Enamel and Dentin Complex. J Contemp Dent Pract 2007 March;(8)3:021-028.

Download Full-text

MTA versus CEM root-end fillings effect on fracture resistance of endodontically treated simulated immature teeth restored with cast metal posts: an in-vitro study

10.21203/rs.3.rs-189967/v1 ◽

2021 ◽

Author(s):

Ensieh Grayli ◽

Abbas Dashtban ◽

Leyla Shadan ◽

Naser Behnampour ◽

Elham Afshari

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

Control Group ◽

P Value ◽

Cast Metal ◽

Immature Teeth ◽

Significant Difference ◽

Group 2 ◽

Group 1

Abstract Background: Endodontically treated immature teeth which are restored with cast metal posts are of the most susceptible teeth to fracture. An apical plug is usually used as root end filling in order to seal the wide apical foramen. The current study was performed to evaluate the effect of different root-end filling materials (MTA and CEM) on fracture resistance of teeth restored with cast metal posts.Methods: A total of 40 extracted intact single-rooted human mandibular premolars (removed for orthodontic reasons) were used in the study. The coronal part of each tooth was removed and root canal preparation was performed. A size 4 Gates Glidden drill was used to enlarge the canal and was passed through the apical foramen in order to simulate an immature apex. Samples were randomly divided into 5 groups according to apical plug (Group 1: No plug, Group 2: 5 mm MTA plug, Group 3: 5 mm CEM plug, Group 4: 2 mm MTA plug, Group 5: 2 mm CEM plug). Post-space preparations were performed and cast metal post-and-cores were fabricated and cemented. Fracture resistance was assessed using a universal testing machine. Fracture thresholds were recorded and data were analyzed using SPSS 16.0 with significance level at P value < 0.05. Results The analysis showed a significant difference of fracture resistance between groups (p-value<0.05). The mean fracture resistance of samples in group 1 was significantly lower than group 2 (p-value=0.003). there was no significant difference between other groups (p-value>0.05).Conclusions: Within the limits of this study, the evidence indicated that placement of a 5 mm MTA apical plug increased the fracture resistance in simulated immature teeth which are restored with cast metal posts, compared to control group (gutta-percha and sealer). While the results were not as promising for a 2 mm MTA apical plug or either 2 or 5 mm CEM apical plug.

Download Full-text

Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Restored with Resin Fiber Post and Stainless Steel Post: An In Vitro Study

Dental Journal of Advance Studies ◽

10.1055/s-0038-1672019 ◽

2015 ◽

Vol 03 (02) ◽

pp. 080-084

Author(s):

Vijay Singh ◽

Poonam Bogra ◽

Saurabh Gupta ◽

Navneet Kukreja ◽

Neha Gupta

Keyword(s):

Stainless Steel ◽

Fracture Resistance ◽

Testing Machine ◽

Compressive Force ◽

Control Group ◽

Fiber Post ◽

Endodontically Treated Teeth ◽

Group I ◽

Significant Difference

AbstractFracture resistance of endodontically treated teeth restored with post. Aims: This study aims to compare the fracture resistance of endodontically treated teeth restored with resin fiber and stainless steel post. Commercially available prefabricated resin fiber post(Dentsply Maillefer Easy Post), prefabricated stainless steel post(Coltene/Whaledent Parapost) were used. Methods and Material: Forty five maxillary central incisors were obturated and divided into 3 groups: Control Group (Group I) without any post (n = 15), Resin Fiber Post Group (Group II) (n = 15) and Stainless Steel Post Group (Group III) (n = 15). In all Groups except control group, post space was prepared; a post was cemented, and a core build-up was provided. All the specimens were subjected to compressive force under a universal testing machine until fracture. Statistical analysis used: The results were analyzed using the variable analysis test (ANOVA). Results: One-way analysis of variance revealed significant difference among test groups. The control group demonstrated highest fracture resistance (925.2183 N), followed by the resin fiber post group (486.7265 N) and stainless steel post group (423.539N). Conclusions: Teeth restored with resin fiber post showed higher fracture resistance values than prefabricated stainless steel post.

Download Full-text

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

Operative Dentistry ◽

10.2341/17-040-l ◽

2018 ◽

Vol 43 (2) ◽

pp. 162-169 ◽

Cited By ~ 3

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>0.05). When groups CR, FCR, and PRF were compared, group PRF showed significantly better fracture strength than did groups CR and FCR (p<0.05). It was determined that there was not any significant difference between group IN and group PRF (p>0.05). Conclusions: Polyethylene ribbon fiber considerably increases the fracture strength of mandibular premolar teeth with MOD cavities restored with composite.

Download Full-text

A Comparative Evaluation of Flexural Strength of Commercially Available Acrylic and Modified Polymethylmethacrylate: An in vitro Study

The Journal of Contemporary Dental Practice ◽

10.5005/jp-journals-10024-1275 ◽

2013 ◽

Vol 14 (1) ◽

pp. 80-83 ◽

Cited By ~ 1

Author(s):

Naveen S Yadav ◽

Teerthesh Jain ◽

Amrita Pandita ◽

SMA Feroz ◽

UK Kartika ◽

...

Keyword(s):

Flexural Strength ◽

Methacrylic Acid ◽

Comparative Evaluation ◽

Testing Machine ◽

Acrylic Resin ◽

Bending Test ◽

Control Group ◽

Diabetic Patients ◽

Denture Stomatitis

ABSTRACT Aim The purpose of this study was to evaluate and compare the flexural strength of commercially available acrylic (trevalone) and modified polymethylmethacrylate (PMMA). Materials and methods Four groups were tested; Group 1— control group regular MMA, group 2—2% methacrylic acid, 88% MMA, group 3—16% methacrylic acid, 84% MMA group 4— 20% methacrylic acid, 80% MMA 15 resin specimens of each group were polymerized. After processing, the specimens were subjected for flexural strength testing using three point bending test in a Universal Testing Machine. All data was statistically analyzed with one-way ANOVA, differences within the groups were analyzed by Scheffe's analysis. Results As the ratio of incorporated methacrylic acid to PMMA increased, the flexural strength decreased. Analysis of data revealed a significant decrease in flexural strength of specimens (p < 0.000) after incorporation of 12%, 16%, 20% methacrylic acid to heat polymerized acrylic resin, when compared with the control group. Lowest flexural strength was observed with specimens containing 20% methacrylic acid and highest flexural strength was observed with specimens containing conventional monomer without methacrylic acid. Conclusion It was observed that as the concentration of methacrylic acid in heat polymerized acrylic resin increases, the flexural strength decreases. Lowest flexural strength was observed with specimens containing 20% methacrylic acid and highest flexural strength was observed with specimens containing conventional monomer without methacrylic acid. Clinical significance The major advantages of addition of methacrylic acid to polymethylmethacrylate could be for the elderly people with restricted manual dexterity or cognitive disturbances, especially for patients who do not follow an adequate denture cleansing protocol and diabetic patients who are more susceptible for denture stomatitis. How to cite this article Jain T, Yadav NS, Pandita A, Feroz SMA, Kartika UK, Singh PP. A Comparative Evaluation of Flexural Strength of Commercially Available Acrylic and Modified Polymethylmethacrylate: An in vitro Study. J Contemp Dent Pract 2013;14(1):80-83.

Download Full-text

Effect of 5% Calcium Hypochlorite on Mechanical Properties of Root Dentin: An in vitro Study

Journal of Operative Dentistry & Endodontics ◽

10.5005/jp-journals-10047-0012 ◽

2016 ◽

Vol 1 (2) ◽

pp. 56-59

Author(s):

Natanasabapathy Velmurugan ◽

Poornima Reddy ◽

Suma Balla ◽

Sandhya S Raghu ◽

Garlapati T Gupta ◽

...

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Modulus Of Elasticity ◽

In Vitro Study ◽

Chlorine Concentration ◽

Control Group ◽

Calcium Hypochlorite ◽

Significant Difference ◽

Root Dentin

ABSTRACT Introduction The aim of this study was to compare in vitro the effect of 5% calcium hypochlorite [Ca(OCl)2] and 5% sodium hypochlorite (NaOCl) on flexural strength and modulus of elasticity of root dentin. Materials and methods The available chlorine concentration of each solution was determined using iodometric titration. Standardized planoparallel dentin bars (n= 20) were divided into two test groups and one control group. The control, group 1, consisted of dentin bars stored in normal saline. The dentin bars in the two test groups were treated by exposure to following solutions: Group 2 to 5% Ca(OCl)2; and group 3 to 5% NaOCl. All the three test solutions were changed once in 15 minutes for 30 minutes. The dentin bars were then loaded to failure using three-point bend test. Results Available chlorine concentration was 64% in both the test solutions. There was a significant reduction in the flexural strength of 5% NaOCl group compared to 5% Ca(OCl)2-treated ones. A significant difference in modulus of elasticity was observed between the test groups and the control groups and also between the 5% Ca(OCl)2 and 5% NaOCl groups. Conclusion Within the limitations of this study, 5% NaOCl reduced the flexural strength and modulus of elasticity of root dentin bars more when compared to 5% Ca(OCl)2. How to cite this article Reddy P, Balla S, Raghu SS, Velmurugan N, Gupta GT, Sahoo HS. Effect of 5% Calcium Hypochlorite on Mechanical Properties of Root Dentin: An in vitro Study. J Oper Dent Endod 2016;1(2):56-59.

Download Full-text

Influence of Exposing Root Canal Dentin to Calcium Hydroxide on Its Flexural Strength

The Indonesian Journal of Dental Research ◽

10.22146/theindjdentres.10063 ◽

2015 ◽

Vol 1 (3) ◽

pp. 143

Author(s):

Diatri Nari Ratih

Keyword(s):

Flexural Strength ◽

Calcium Hydroxide ◽

Root Canal ◽

Artificial Saliva ◽

Testing Machine ◽

In Vitro Study ◽

Control Group ◽

Sterile Saline ◽

Root Canal Dentin

Calcium hydroxide has been used extensively in endodontic treatments, for instance as an intra-canal dressing; however, the exposure of root canal dentin to calcium hydroxide may affect its flexural strength and could have important clinical implications for endodontic treatment. The purpose of this in vitro study was to investigate the influence of calcium hydroxide on the flexural strength of root canal dentin.Seventy-two extracted single-rooted human mandibular premolars were used in this study. Each tooth was instrumented using crown-down technique and was irrigated using sterile saline. The teeth were assigned into three groups of 24 each. The prepared root canal system of each tooth was filled with calcium hydroxide mixed with sterile saline (group 1), a calcium hydroxide commercially available product (UltraCal®) (group 2) or saline solution (group 3, as control). The apices and access opening were sealed using composite resin, and the teeth were immersed in artificial saliva. After 7, 14 and 30 days of immersion, the inner root canal dentin of 8 teeth respectively from each group were sectioned to create dentin bars (1 X 1 mm, with 7 mm in length). Each dentin bar then was subjected to a three-point bending flexural test using MTS (Universal Testing Machine). Data gathered were then analyzed using two-way ANOVA, followed by Tukey’s test with the level of significance of 95%. The results showed that exposure to calcium hydroxide either using calcium hydroxide mixed with sterile saline or UltraCal® for 14 and 30 days can reduce flexural strength of root canal dentin compared to control group (p<0.05). In contrast, after 7 days exposure, there was no significantly different of flexural strength between three groups (p>0.05). It can be concluded that calcium hydroxide reduced the flexural strength of root canal dentin. The longer the exposure to calcium hydroxide would produce a greater effect on flexural strength of root canal dentin.

Download Full-text

Spectrophotometric Analysis Evaluating Apical Microleakage in Retrograde Filling using GIC, MTA and Biodentine: An in-vitro study

10.21203/rs.2.15368/v3 ◽

2020 ◽

Author(s):

Manisha Nepal ◽

Snigdha Shubham ◽

Rupam Tripathi ◽

Jwolan Khadka ◽

Deepa Kunwar ◽

...

Keyword(s):

Negative Control Group ◽

Positive Control ◽

Negative Control ◽

Control Group ◽

Filling Materials ◽

Diamond Bur ◽

Retrograde Filling ◽

Significant Difference ◽

Supernatant Solution

Abstract Background The present study compares the apical microleakage of three different root-end filling materials in which the retrograde cavity is prepared by two different burs. Methods Eighty extracted single rooted maxillary and mandibular premolars were taken. Root canal treatment was completed. Apical 3 mm of all the teeth were resected with diamond disk. The tooth were divided into four groups with two subgroups for each group containing 10 tooth (N= 10) as: Group IA (Negative Control and IB (Positive Control); Group IIA and IIB: Prepared with round carbide bur and round diamond bur respectively, filled with GIC; Group IIIA and IIIB: Prepared with round carbide bur and round diamond bur respectively, filled with MTA; Group IVA and IVB: Prepared with round carbide bur and round diamond bur, filled with Biodentine. After applying two coats of nail varnish leaving apical 3 mm (except for negative control group) all teeth were immersed in 2% methylene blue for 3 days and again in 65% nitric acid for next 3 days for extraction of dye. The obtained solution was then transferred to eppendorf tube and centrifuged in microcentrifuges at 14,000 revolution per minutes (RPM) for 5 minutes. Optical density or absorbance of the supernatant solution was measured with UV spectrophotometer at 550 nm. Results The absorbance of the supernatant solution after dye extraction is decreasing in the order of positive control> GIC> MTA> Biodentine> negative control group. The significant difference was observed between GIC and MTA (p=0.0001) and GIC and Biodentine (p=0.0001) with two different burs but statistically non-significant difference was observed between MTA and Biodentine with Carbide bur (p=0.127) and Diamond bur (p=0.496) respectively. Conclusions Within the limitations of the present study, it can be concluded that Biodentine and MTA showed less microleakage as compared to GIC. There is no significant difference between mean microleakage of MTA and Biodentine. However, the mean OD of the Biodentine was least of all evaluated materials. Preparation of the root-end using round carbide bur as well as round diamond burs showed comparable microleakage for all three filling materials.

Download Full-text

Transverse Strength of Heat Cured Acrylic Resin After Immersed in 0, 2% Chlorhexidine Gluconate Mouthwash (In Vitro)

UI Proceedings on Health and Medicine ◽

10.7454/uiphm.v1i0.33 ◽

2017 ◽

Vol 1 ◽

Author(s):

Annisa Mayang Rusdi ◽

Lasminda Syafiar ◽

Astrid Yudhit

Keyword(s):

Testing Machine ◽

Acrylic Resin ◽

Chlorhexidine Gluconate ◽

P Value ◽

Group V ◽

Group Iii ◽

Transverse Strength ◽

Group I ◽

Significant Difference

Objective: The purpose of this study was to evaluate transverse strength of heat cured acrylic resin after immersed in 0,2% chlorhexidine gluconate mouthwash for 15, 30, 45, and 60 minutes.Methods: This was an experimental laboratory study with posttest only group design. The samples were heat cured acrylic resin plate with size 65mm x 10mm x 2,5mm. Polymerization of the heat cured acrylic was done by water bath (74 °C for 2hrs followed by 100 °C for 1hr). Totally 30 samples were prepared and divided into 5 groups (n=6) which are group I as control, and others were immersed in 0, 2% chlorhexidine gluconate, group II (15 minutes), group III (30 minutes), group IV (45 minutes) and group V (60 minutes) respectively. The transverse strength was test using Torsee’s Universal Testing machine, Japan with crosshead 1/10 mm/seconds. The data was statistically analyzed using one way ANOVA (p≤0,005).Results: Means and Standard deviation of Transverse strength were 92.382±11.786 N/mm2, 92.186±13.349 N/mm2,92.578±12.492 N/mm2, 92.382±13.939 N/mm2, and 91.989±12.285 N/mm2 for group I, II, III, IV, and V respectively. Statistic analyzed showed no significant difference among groups with p value= 1,000 (p < 0, 05).Conclusion: The immersion in 0, 2% chlorhexidine gluconate mouthwash at different period does not changed transverse strength of heat cured acrylic resin.

Download Full-text

Evaluation of a novel fixed-space maintainer made of light-cured acrylic resin: an in vitro study

BDJ Open ◽

10.1038/s41405-020-00046-1 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Yasser R. Souror ◽

Tayseer Maaly ◽

Mohammed Sameer Khawandanah

Keyword(s):

Flexural Strength ◽

Bond Strength ◽

Shear Bond Strength ◽

Testing Machine ◽

Acrylic Resin ◽

Tooth Surface ◽

Significant Difference ◽

Space Maintainer ◽

Fixed Space

Abstract To evaluate a fixed-space maintainer made of light-cure acrylic resin (LCAR) for its flexural and shear bond strength using different bonding systems to the enamel. 45 extracted primary teeth were selected. They were randomly divided into three equal groups (n = 15) along with the type of adhesive system (Tetric Flow, Transbond XT, and Fuji Ortho LC) used for bonding (LCAR) to the tooth surface. Surfaces were treated; LCAR was attached to the treated surfaces using a split Teflon mold. For flexural strength testing, ten bars of LCAR were made using another Teflon-split mold. Shear bond strength and mean flexural strength values were evaluated by a universal testing machine. The highest values of bond strength were recorded for Transbond XT, followed by Tetric Flow, while the lowest values were for Fuji Ortho LC. Various groups had a significant difference as investigated by ANOVA. ARI scores showed no significant difference in debond sites. Mean value and standard deviation of flexural strength for LCAR were 82.83 ± 5.2. LCAR has superior mechanical properties and could be an alternative to currently-in-use space maintainer though in vivo and in vitro trials are needed to progress the ultimate design of LCAR.

Download Full-text