scholarly journals Effect of preheating on the cytotoxicity of bulk-fill composite resins

2020 ◽  
Vol 14 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Mohammad Esmaeel Ebrahimi Chaharom ◽  
Mahmoud Bahari ◽  
Leila Safyari ◽  
Hossein Safarvand ◽  
Hajar Shafaei ◽  
...  
Keyword(s):  
Room Temperature ◽  
Composite Resin ◽  
Human Fibroblasts ◽  
Composite Resins ◽  
Significance Level ◽  
Significant Difference ◽  
Different Types ◽  
The Mean ◽  
Post Hoc ◽  
Cylindrical Samples

Background . Due to the effect of pre-heating on the degree of conversion of composite resins and the possible effect on cytotoxicity, the effect of pre-heating of bulk-fill composite resins was investigated on cytotoxicity in this study. Methods. In this study, three different types of composite resin were used, including Tetric N-Ceram Bulk-Fil, Xtrafil, and Xtrabase. From each composite resin, 10 cylindrical samples (5 mm in diameter and 4 mm in height) were prepared, with five samples preheated to 68°C, and the other five samples polymerized at room temperature (25°C). Twenty-four hours after polymerization, cytotoxicity was assessed by MTT assay on human fibroblasts. Statistical analysis of data was carried out with two-way ANOVA and Sidak Post-Hoc. The significance level of the test was determined at 0.05. Results. There was no statistically significant difference between the mean percentage of cytotoxicity in terms of pre-heating (P>0.05), but the cytotoxicity of the studied composite resins was significantly different (P<0.001). The cytotoxicity of Tetric N-Ceram Bulk-fil composite resin was higher than that of the two other composite resins. Conclusion. Pre-heating of bulk-fill composite resin did not affect their cytotoxicity. In addition, the cytotoxicity of different bulk-fill composite resins was not the same.

scholarly journals Oxygen Saturation in the Dental Pulp of Maxillary and Mandibular Molars - Part 2

2017 ◽  
Vol 28 (6) ◽  
pp. 704-709 ◽  
Author(s):  
Carlos Estrela ◽  
Keila SA Oliveira ◽  
Ana Helena G Alencar ◽  
Fernando B Barletta ◽  
Cyntia RA Estrela ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Dental Pulp ◽  
Oxygen Saturation Level ◽  
Significance Level ◽  
Cold Stimulus ◽  
Mandibular Molars ◽  
Maxillary Molars ◽  
Significant Difference ◽  
The Mean ◽  
Post Hoc

Abstract This study determined the oxygen saturation (SaO2) in dental pulp of healthy maxillary and mandibular molars. Mean of SaO2 was evaluated in 112 maxillary and mandibular molars using pulse oximetry. Quantitative variables were described by mean and standard deviation. Variables with symmetric distribution were compared by Student t test and Mann-Whitney test. Pearson’s correlation coefficient was used to correlate quantitative variables. Analysis of variance was used to assess differences in SaO2 levels between the molar groups, followed by post-hoc Tukey. The significance level established at p<0.05. Mean of oxygen saturation for the 112 molar dental pulps was 85.09%. There was no significant correlation (r=-0.007; p=0.977) between the mean of SaO2 of molar pulps with patient´s indicator finger (92.89%). There was a significant difference (p=0.037) between the mean of SaO2 of the first (85.76%) and second maxillary molars (81.87%), and it was not significant (p=0.1775) between the first and second mandibular molars. Maxillary molars had lower pulpal SaO2 (83.59%) than mandibular molars (86.89%) (p=0.018). The mean of the patient’s response time to the cold stimulus was 1.12 s (maxillary molars 1.25 s and mandibular molars 0.99 s)(p=0.052). There was no significant correlation between the time response of the patient to the cold stimulus and the SaO2 for molars. The mean oxygen saturation level was 85.09%. The mandibular molars presented higher SaO2 level than maxillary molars.

scholarly journals Effect of different bonding techniques on marginal adaptation of Harmonize composite resin at different storage times.

2020 ◽  
Author(s):  
Ebaa Ibrahim Alagha
Keyword(s):  
Composite Resin ◽  
Storage Period ◽  
Adhesive System ◽  
Marginal Adaptation ◽  
Gap Formation ◽  
Significance Level ◽  
Significant Difference ◽  
Post Hoc ◽  
Storage Times ◽  
Self Etch

Abstract Background This study evaluated the effect of different bonding techniques on marginal adaptation of Harmonize composite resin at different storage times. Methods Hundred twenty upper premolars were divided into two main groups (n = 60) according to the type of the adhesive system used (self-etch adhesive system or total etch adhesive system). Each group was further divided into three subgroups (20 teeth each) according to the storage times into one day, three months and six months. Standardized Class II cavities were prepared and restored with Harmonize composite incrementally. Teeth were stored in distilled water at room temperature. After each storage time, teeth were sectioned buccolingually into two halves and examined under digital stereomicroscope for the purpose of gap formation detection and scanning electron microscope examination was done to evaluate resin-dentin interfaces. The recorded values were tabulated and statistically analyzed. Regression model using three-way Analysis of Variance (ANOVA) was used for testing significance of the effect of adhesive system, storage period and their interactions on the mean gap area. Tukey’s post-hoc test was used for pair-wise comparisons between the groups when ANOVA test is significant. The significance level was set at P ≤ 0.05. Results Self-etch adhesive system showed statistically significant higher mean gap area than Total-etch adhesive system at the occlusal and cervical margins. Six months period showed the statistically significant highest mean gap area. There was no statistically significant difference between 1 day and 3 months periods; both showed the statistically significant lowest mean gap area values respectively at the occlusal and cervical margins. Conclusions Total-etch adhesive system enhances the marginal adaptation when compared to self-etch adhesive system and the storage period of composite resin in water has adverse effect on the marginal adaptation to all groups with time.

scholarly journals Fracture resistance of veneers in premolars

2018 ◽  
Vol 12 (02) ◽  
pp. 191-198 ◽  
Author(s):  
Ludmilla Azevedo Linhares ◽  
Larissa Fernanda Pottmaier ◽  
Guilherme Carpena Lopes
Keyword(s):  
Fracture Resistance ◽  
Composite Resin ◽  
Lithium Disilicate ◽  
Mean Values ◽  
Significant Difference ◽  
Mode Of Failure ◽  
The Mean ◽  
Tooth Preparation ◽  
Post Hoc ◽  
One Way Anova

ABSTRACT Objective: The purpose of the study was to compare the fracture resistance of ceramic veneers and composite resin veneers with and without dental preparation. Materials and Methods: Forty freshly extracted mandibular premolars were selected and randomly assigned into four groups (n = 10): Group NPR = no dental preparation and direct veneer with 0.2 mm thick composite resin (Amelogen Plus, Ultradent); Group NPC = no dental preparation and 0.2 mm thick lithium disilicate ceramic veneer (IPS e.max Press, Ivoclar Vivadent); Group P2C = Tooth preparation of 0.2 mm and 0.2 mm thick ceramic veneer (IPS e.max Press); and Group P5C = Tooth preparation of 0.5 mm and 0.5 mm-thick ceramic veneer (IPS e.max Press). In all groups, the restorations covered 1 mm of the occlusal surface of the buccal cusp, and the thickness of this area was the same of the buccal area (0.2 mm or 0.5 mm). After the luting procedure, all groups were thermocycled (10,000 cycles, 5°C–55°C) and subjected to fracture resistance test under compression (Instron 4444 with a crosshead speed of 0.5 mm/min). The mode of failure analysis was performed under a ×10 magnification. Data were subjected to one-way ANOVA and Duncan's post hoc test (P < 0.05). Results: The mean fracture resistance (men ± standard deviation) was NPR = 690.33 ± 233, NPC = 790.52 ± 408, P2C = 1131.34 ± 341, and P5C = 983.56 ± 202. There were significant differences of the fracture resistance values between all groups (P = 0.013). NPR and NPC groups showed mean values of fracture resistance significantly lower than P2C. However, P5C presented intermediate values without a significant difference from the other groups. The mode of failure for all groups was mixed (60%), cohesive failures (20%), root failures (15%), and adhesive failures (5%). Conclusion: Minimally invasive tooth preparation (0.2-mm) allowed to achieve higher fracture resistance in premolars restored with lithium disilicate ceramic veneers. Attention should be given to the 0.5 mm preparation since catastrophic fractures only happened when this preparation depth was performed.

scholarly journals Comparison of time-dependent changes in the surface hardness of different composite resins

2013 ◽  
Vol 07 (S 01) ◽  
pp. S020-S025 ◽  
Author(s):  
Suat Ozcan ◽  
Ihsan Yikilgan ◽  
Mine Betul Uctasli ◽  
Oya Bala ◽  
Zeliha Gonca Bek Kurklu
Keyword(s):  
Composite Resin ◽  
Surface Hardness ◽  
Multiple Comparisons ◽  
Composite Resins ◽  
Time Dependent ◽  
Bottom Surface ◽  
Significance Level ◽  
Hardness Tester ◽  
Significant Difference ◽  
Hardness Values

ABSTRACT Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vicker′s hardness tester. The samples were then stored at 37°C and 100% humidity. After 24 h and 7, 30 and 90 days, the top and bottom surface hardness of the samples was measured. In each measurement, the rate between the hardness of the top and bottom surfaces were recorded as the hardness rate. Statistical analysis was performed by one-way analysis of variance, multiple comparisons by Tukey′s test and binary comparisons by t-test with a significance level of P = 0.05. Results: The highest hardness values were obtained from each two surfaces of Majesty Posterior and the lowest from Filtek Silorane. Both the top and bottom surface hardness of the methacrylate based composite resins was high and there was a statistically significant difference between the top and bottom hardness values of only the silorane-based composite, Filtek Silorane (p < 0.05). The lowest was obtained with Filtek Silorane. The hardness values of all test groups increased after 24 h (p < 0.05). Conclusions: Although silorane-based composite resin Filtek Silorane showed adequate hardness ratio, the use of incremental technic during application is more important than methacrylate based composites.

scholarly journals Comparison of the Ability of Two Brands of CBCT with That of SEM to Detect the Marginal Leakage of Class V Composite Resin Restorations

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Mitra Karbasi Kheir ◽  
Leili Khayam
Keyword(s):  
Composite Resin ◽  
Nitrate Solution ◽  
Silver Nitrate Solution ◽  
Composite Resins ◽  
Rank Test ◽  
Sem Images ◽  
Class V ◽  
Significant Difference ◽  
The Mean ◽  
Composite Resin Restorations

Objectives. This study was carried out to compare the ability of two common brands of cone-beam computed tomography (CBCT), including New Tom and Planmeca, to detect the marginal leakage of class V composite resins. The ability of each of the two brands of CBCT to detect the marginal leakage of class V composite resins was also compared with that of scanning electron microscopy (SEM). Methods. Class V cavities were prepared on the buccal surface of sixteen extracted caries-free human premolars. Cavities were conditioned and filled with composite resin. The teeth were immersed in 50% weight/weight aqueous silver nitrate solution for 24 hours. They were then taken out and rinsed with distilled water. Next, they were put in a developing solution. They were first viewed with New Tom and Planmeca CBCT units and were then sectioned and evaluated by an SEM. Results. The results of the Wilcoxon signed-rank test showed no significant difference between the mean marginal leakage scores of New Tom and Planmeca CBCT images ( p value = 0.157) and between those of New Tom CBCT and SEM images ( p value = 0.098). However, there was a significant difference between the mean marginal leakage scores of Planmeca CBCT and SEM images ( p value = 0.023). Conclusion. There were no significant differences between New Tom and Planmeca CBCT units in the detection of marginal leakage of class V composite resins. However, when these CBCT units were compared with the SEM, the New Tom CBCT unit could detect the marginal leakage better than Planmeca.

scholarly journals The Comparative Effect of Online Self-Correction, Peer- correction, and Teacher Correction in Descriptive Writing Tasks on Intermediate EFL Learners’ Grammar Knowledge The Prospect of Mobile Assisted Language Learning (MALL)

2018 ◽  
Vol 7 (3) ◽  
pp. 14 ◽  
Author(s):  
Mojtaba Aghajani ◽  
Mahsa Zoghipour
Keyword(s):  
Language Learning ◽  
Significance Level ◽  
Efl Learners ◽  
Mobile Assisted Language Learning ◽  
Significant Difference ◽  
Different Types ◽  
Exact Difference ◽  
Post Hoc ◽  
Grammar Knowledge ◽  
Descriptive Writing

60 participants of the study were selected based on their scores on the Nelson proficiency test and divided into three Telegram groups comprising a peer-correction, a self-correction and a teacher-correction group, each with 20 students. The pretest was administered to measure the subjects' grammar knowledge. Subsequently, three Telegram groups each with 21 members (20 students + 1 teacher) were formed. Then during a course of nearly one academic term the grammatical notions were taught by the teacher. The members were required to write on the prompt in about 50 to 70 words and post it on the group. Then, their writings were corrected through self-correction, peer-correction and teacher-correction under the feedback provided by the researcher. The study used a pretest-posttest design to compare the learners’ progress after the application of three different types of treatment. One-Way between-groups ANOVA was run to test whether there was any statistically significant difference in grammar knowledge in descriptive writing of intermediate EFL learners’ who receive mobile-assisted self-correction, peer-correction and teacher-correction. The researcher also used Post-Hoc Tests to determine the exact difference between correction methods. Online self-correction, peer-correction and teacher-correction were the independent variables and grammar knowledge was the dependent variable. Examining the result of the study prove that significance level between self-correction and teacher-correction was the strongest (sig. = 0.000) but the significance level was a little less strong between peer-correction and teacher-correction whereas no significance was observed between self-correction and peer-correction.

Clinical Measurement of Maximum Mouth Opening in Children Aged 6–12

2021 ◽  
Vol 45 (3) ◽  
pp. 216-220
Author(s):  
Syed Aliya ◽  
Harsimran Kaur ◽  
Nishita Garg ◽  
Rishika ◽  
Ramakrishna Yeluri
Keyword(s):  
Age Groups ◽  
Mouth Opening ◽  
Age Group ◽  
Significance Level ◽  
Significant Difference ◽  
Group 3 ◽  
Bonferroni Test ◽  
The Mean ◽  
Group 2 ◽  
Post Hoc

Objective: To evaluate the clinical maximum mouth opening in children and its correlation with age, and sex. Study Design: Three hundred children of age 6–12 years, from different schools of Moradabad city were included. The participants were divided into three groups based on their age i.e Group 1 (n=100) 6–8 years, Group 2 (n=100) 8–10 years and Group 3 (n=100) 10–12 yrs. Three recordings of maximum mouth opening (MMO) were obtained using digital vernier caliper and the mean of three was considered as the MMO of that child. The data was analyzed using Spearman correlation, ANOVA with post- hoc Bonferroni test. The significance level was predetermined at p≤0.05 .Results: The mean MMO for children of Moradabad of aged 6–8yrs in boys is 39.87 ± 4.91 mm and in girls is 36.85± 4.09 mm. In 8–10 yeas age group, the MMO in boys is 44.5± 5.1 mm and in girls 41.77± 5.24 mm. In 10–12 year age group, the MMO in boys is 49.63± 5.56 mm and in girls is 49.33±5.32 mm respectively. The MMO was found to be higher in boys in all the three age groups. Conclusions: There was a significant difference in values of MMO in all the three age groups with boys having higher MMO values when compared to girls. Varying range of MMO values was observed within three age groups.

scholarly journals Comparison of Sprint Reaction and Visual Reaction Times of Athletes in Different Branches

2016 ◽  
Vol 5 (1) ◽  
pp. 94 ◽  
Author(s):  
Murat Akyüz ◽  
Başar Basri Uzaldi ◽  
Öznur Akyüz ◽  
Yeliz Doğru
Keyword(s):  
Female Athletes ◽  
Statistical Significance ◽  
Reaction Times ◽  
Significance Level ◽  
Study Results ◽  
Significant Difference ◽  
Package Program ◽  
Visual Reaction ◽  
The Mean ◽  
Post Hoc

The aims of this study are to analyse sprint reaction and visual reaction times of female athletes of different branches competing in Professional leagues and to show the differences between them. 42 voluntary female athletes from various branches of Professional leagues of İstanbul (volleyball, basketball, handball) were included in the experiment group of this study. Lafeyetta Moart Reaction meter for visual reaction measurements and Fusionsport Pro Photocell meter for sprint reaction test measurements were used for participating athletes. Mean measurements were obtained for all tests. SPSS 22 statistical package program was used for analysing data for Windows. Kruskall Wallis, Anova and Post Hoc test was used while comparing the data between the groups. Statistical significance level was taken as p<0.05. Study results show that no statistically significant difference was observed among the mean visual reaction values of basketball, volleyball and handball players (p>0.05). A statistically significant difference was observed among the averages of sprint reaction total values of players (p<0.05). According to visual reaction measurements, handball players were better compared with the other branches (p<0.05). No relationship was observed between visual reaction and sprint reactions of players among the branches.

Effects of Relationship Enrichment Training on Improving Marital Satisfaction of Infertile Couples: A Randomized Control Trial

2021 ◽  
Vol 17 ◽  
Author(s):  
Seyedeh Zahra Masoumi ◽  
Khodayar Oshvandi ◽  
Masoumeh Rostami-Moez ◽  
Arezoo Shayan ◽  
Farideh Kazemi
Keyword(s):  
Marital Satisfaction ◽  
Intervention Group ◽  
Analysis Of Covariance ◽  
Control Group ◽  
Chi Square ◽  
Significance Level ◽  
Significant Difference ◽  
The Mean ◽  
Infertile Couples ◽  
Relationship Enrichment

Background: Infertility can cause low marital satisfaction. Marital satisfaction has an important effect on infertile couples’ health. Objective: This study aimed to assess the effect of relationship enrichment training on improving the marital satisfaction of infertile couples. Methods: This randomized clinical trial was conducted on 50 infertile couples in the infertility center of Fatemieh Hospital in Hamadan, Iran in 2018. Participants were matched for demographic characteristics and randomly assigned to intervention and control groups (each group had 25 couples). Informed consent was obtained from all participants. The Enrich Marital Satisfaction questionnaire and demographic information were used to collect data before the study and two months after the intervention. Two trained midwifery students taught only the intervention group the relationship enrichment topics in seven sessions (each session = 90 minutes). The data were analyzed by SPSS Statistics version 21 using analysis of covariance, independent t-test, chi-square, and Mann–Whitney. The significance level was set at p ≤ 0.05. Results: There was no significant difference in demographic and obstetric information between the two groups (p >0.05). The mean of marital satisfaction in the intervention group significantly increased among women and men from 151.00 ±28.61 to 154.88 ±22.62 and from 152.56 ±27.33 to 159.24 ±22.14, respectively, (p <0.001). Conversely, the mean of marital satisfaction decreased among women and men from 158.13 ±13.86 to 146.25 ±19.53 and from 164.25 ±17.00 to 153.17 ±27.50 in the control group (p=0.02). Conclusion: Relationship enrichment training can be effective in promoting the marital satisfaction of infertile couples. Registration number: The National Center for Strategic Research in medical education, No. 960185.

scholarly journals Impact of refrigeration on the surface hardness of hybrid and microfilled composite resins

2009 ◽  
Vol 20 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Fernando Henrique Ruppel Osternack ◽  
Danilo Biazzetto de Menezes Caldas ◽  
Rodrigo Nunes Rached ◽  
Sérgio Vieira ◽  
Jeffrey A. Platt ◽  
...  
Keyword(s):  
Room Temperature ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Knoop Hardness ◽  
Composite Resins ◽  
Bottom Surface ◽  
Steel Mold ◽  
Polymerization Condition ◽  
Post Hoc

This in vitro study evaluated the Knoop hardness of the composite resins Charisma® (C) and Durafill VS® (D) polymerized in 3 different conditions: at room temperature (A) (23 ± 1°C); refrigerated at 4 ± 1°C and immediately photo-activated after removal from the refrigerator (0); and, refrigerated at 4 ± 1°C and photo-activated after a bench time of 15 min at room temperature (15). One hundred and twenty specimens (4 mm diameter and 2 mm depth) were made using a stainless steel mold and following manufacturer's instructions. All specimens were tested immediately after polymerization (I) and after 7 days of water storage in the dark at room temperature (7d). The data were subjected to ANOVA and post-hoc Tukey's test (a=0.05). On the top surface, CAI was statistically similar to C15I and DAI to D15I (p>0.05). On the bottom surface, CAI presented higher hardness values when compared to COI and C15I (p<0.05). The D groups showed no significant differences (p>0.05) on the bottom surfaces for any tested polymerization condition. After 7 days of storage, the Knoop hardness decreased significantly (p<0.05) for groups C7d and D7d except for C07d, which was not different from COI at either surface (p>0.05). D07d showed higher Knoop hardness (p<0.05) values on the top surface when compared to the other groups.

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