scholarly journals Evaluation of the effect of different surface treatments on the bond strength of non-precious alloy‒ceramic interface: An SEM study

2019 ◽  
Vol 13 (3) ◽  
pp. 200-207
Author(s):  
Vikram M. Belkhode ◽  
Sharayu V. Nimonkar ◽  
S. R. Godbole ◽  
Pranali Nimonkar ◽  
Seema Sathe ◽  
...  

Background. Dental porcelain has excellent esthetics in combination with biocompatibility and is one of the most commonly used restorative materials. Its low tensile strength remains a major drawback. The porcelain-fused-to-metal restorations have been introduced to increase the fracture resistance of dental porcelain. The aim of this study was to evaluate the effect of different surface treatments on the bond strength of a non-precious alloy to ceramic. Methods. The present cross-sectional observational study was conducted with forty samples of cobalt‒chromium that were fabricated with porcelain interposed between the two metal test pieces. The metal was subjected to combinations of different surface treatments. The samples group A (n=10) were not subjected to any surface treatments. Group B samples underwent sandblasting and surface grinding. Group C samples were subjected to sandblasting, surface grinding and degassing; and group D samples underwent sandblasting, surface grinding, ultrasonic cleaning and degassing. The tensile bond strength was measured in a universal testing machine, and a scanning electron microscope (SEM) was used to obtain images of the samples after surface treatment to determine the surface irregularities and after the debonding of the samples for the type of the bond failure. ANOVA was used for the statistical analysis. Results. The results showed significant variations in the tensile bond strength between the four groups (F=251.05, P=0.000). The SEM images of group A showed no surface irregularities; group C samples exhibited surface irregularities more than those in group B. Group D had the highest surface irregularities. SEM evaluations showed a statistically significant difference in the type of bond failure (P<0.001). Conclusion. Based on the results of this study, it can be concluded that the surface treatments on the metal increased the bond strength of the metal‒ceramic interface significantly. A combination of sandblasting, surface grinding and ultrasonic cleaning, followed by degassing, resulted in the highest tensile bond strength.

2015 ◽  
Vol 5 (2) ◽  
pp. 20-24
Author(s):  
Gaurav Chaudhary ◽  
Pawan Kumar Chandra ◽  
Rakesh Sharma ◽  
P Narayana Prasad ◽  
Sonia Gera

Objective: To evaluate the influence of bracket base designs on shear bond strength of ceramic brackets bonded to natural teeth and to determine the common site of bond failure.Materials & Method: 120 therapeutically extracted maxillary first premolars were divided into six groups of 20 samples each and were mounted in resin blocks. Each sample was bonded with bracket of that particular group and subjected to thermocycling. The shear bond strength was measured using Universal Testing Machine. After debonding, the teeth and brackets were examined under stereo-microscope for adhesive remnant index.Result: Ceramic brackets with ball base design (Group A) yielded statistically highest shear bond strength followed by microcrystalline base (Group D), dimple base (Group E), mesh base (Group C) and dove tail base (Group B) design. Ceramic brackets yield higher bond strength than metal brackets (Group F) irrespective of base design. Insignificant difference was seen between Group A and Group D and between Group B and Group C. Bond failure between adhesive and bracket (Type 3) was seen in 80% of the brackets with ball base design and bond failure between adhesive and bracket (Type 1) was seen in 80% of brackets with dove tail base design.Conclusion: Bracket base design is an important consideration for shear bond strength. Base design with more number of undercuts offer higher shear bond strength. Ceramic brackets with more number of mechanical undercuts were less likely to bond failure at adhesive bracket base interface and vice versa


2017 ◽  
Vol 62 (4) ◽  
pp. 415-420 ◽  
Author(s):  
Julia H. Seeliger ◽  
Ute U. Botzenhart ◽  
Tomasz Gedrange ◽  
Karol Kozak ◽  
Lukas Stepien ◽  
...  

AbstractAim:The aim of this study was a comparison of shear bond strength (SBS) on tooth enamel of different primers combined with the adhesive paste Transbond XT.Materials and methods:Forty bovine teeth were used in order to create 40 test blocks. The blocks were divided into four groups of 10 blocks each: group A – sample primer (SP); group B – Opal Seal (OS); group C – Transbond Plus SEP (TSEP); group D – Transbond XT Primer (TXT). After surface preparation and application of the primer, respectively, two stainless steel brackets were fixed on each tooth by using Transbond XT. Accordingly, 80 brackets were debonded (n=20). Shear bond strength and adhesive remnant index (ARI) scores were evaluated. Statistical analyses were performed by using the Student’s t-test and Mann-Whitney U test.Results:All tested groups revealed high shear bond strength in a similar size range. There were no significant differences between the groups concerning shear bond strength. The ARI scores of group C showed significantly lower ARI scores (0 and 1) than that of group D. Apart from that there was no statistical difference.Conclusion:In combination with the adhesive paste Transbond XT, all tested primers were suitable for fixing orthodontic brackets. The primers could be changed according to the clinical situation.


2019 ◽  
Vol 07 (01) ◽  
pp. 012-018 ◽  
Author(s):  
Eeshita Sharma ◽  
Manjit Kumar ◽  
Rohit Sharma ◽  
Ajay Bansal ◽  
Sumit Katoch

Abstract Statement of Problem Acrylic teeth are preferred to porcelain teeth in dentures as they unite chemically with denture base resin, but their fracture from denture is common. Purpose The purpose of this study was to improve the bond strength of denture teeth to acrylic resin denture base by chemical or mechanical modification of the ridge lap surface of denture teeth. Materials and Methods Total 100 artificial cross-linked acrylic resin central incisors were divided into five groups: group A, 20 samples without modification (control group); group B, 20 samples (ridge lap surface of teeth treated with monomer); group C, 20 samples (ridge lap surface of teeth treated with monomer and the glaze layer removed with aluminum oxide abrasive stone); group D, 20 samples (ridge lap surface of teeth treated with dichloromethane); and group E, 20 samples (dichloromethane application followed by abrasion with aluminum oxide stone on ridge lap surface of teeth). They were mounted on wax blocks, and the blocks were acrylized. The bond strength values were obtained by subjecting the samples to shear compressive load under universal testing machine. Result The results were subjected to statistical analysis by applying analysis of variance and Bonferroni test for multiple group comparisons, and graphs were plotted. The mean value of bond strength was highest for group E (modified by aluminum oxide abrasion prior to dichloromethane application), followed by group C (modified by aluminum oxide abrasion prior to monomer application), group D (modified by dichloromethane application), group B (modified by monomer application), and lastly group A (control group). Significantly improved bond strength values were obtained in modified groups as compared with the control group. Conclusion Dichloromethane application followed by aluminum oxide abrasion provided the highest bond strength and is recommended to prevent debonding of the teeth from the denture base.


2017 ◽  
Vol 50 (4) ◽  
pp. 178
Author(s):  
Tunjung Nugraheni ◽  
N Nuryono ◽  
Siti Sunarintyas ◽  
Ema Mulyawati

Background: Restoration of the teeth immediately after bleaching with 35% hydrogen peroxide (H2O2) is contraindicated due to the remnant of free radicals that will stay inside enamel and dentin for 1-3 weeks and reduce the adhesion of composite resin. Sodium ascorbate is an antioxidant substance known to bind free radical residues, thereby shortening the delay in restoration. Purpose: The purpose of this study was to examine the resin bond strength of bleached dentin influenced by the application of 35% sodium ascorbate. Methods: Nine premolars were divided into their crown and root sections, with the crown subsequently being cut into four equal parts to obtain 36 samples. These were then divided into four groups, each containing nine samples. Group A (control): samples were bleached using35% hydrogen peroxide, immersed in an artificial saliva, stored in an incubator at 37°C for seven days and then filled with a composite resin. Group B:samples were also bleached by means of 35% H2O2 followed by one application of 0.025 ml 35% sodium ascorbate for 5 minutes and restored with composite resin. Group C: samples were bleached with 35% H2O2, followed by two applications of 0.025 ml 35% sodium ascorbate for 5 minutes, and restored with a composite resin. Group D: dentin was bleached with 35% H2O2 followed by three applications of 0.025 ml sodium ascorbate 35% for 5 minutes and restored with a composite resin. The shear bond strength of the composite resin was measured by a universal testing instrument (Zwick, USA). Data was analyzed by means of one-way Anova and LSD. Results: The highest mean shear bond strength of composite resin was in group C, while the lowest was in group B. The result of one-way Anova indicated a difference in the shear bond strength of composite resin in the four treatment groups (p < 0.05). An LSD test showed there to be a difference in shear bond strength of composite resin between group A and groups C and D or between group B and groups C and D. There was no difference in shear bond strength of composite resin between group A and group B or between group C and group D. Conclusion: Application frequency of 35% sodium ascorbate affect on shear bond strength of composite resin restoration in bleached dentin by 35% H2O2.


2014 ◽  
Vol 17 (3) ◽  
pp. 50
Author(s):  
Celina Wanderley de Abreu ◽  
Gilberto Duarte Filho ◽  
Alberto Noriyuki Kojima ◽  
Renato Morales Jóias ◽  
Alfredo Mikail Melo Mesquita

<p><span style="font-size: medium;">The objective of this study was to evaluate the influence of different speeds using the piston device in the shear bond strength. 48 cylinders of composed resin had been confectioned (Solidex),and were divided randomly in four groups (n=12).</span><span style="font-size: medium;">  </span><span style="font-size: medium;">The specimens were adapted to the device for the</span><span style="font-size: medium;">  </span><span style="font-size: medium;">shear bond strenth test and were taken to an universal testing machine with a load cell of 1000Kg. The test were carried through with four different speeds: group A: 0,5; group B: 1,0; group C: 1,5 and group D: 2,0mm/min. The mean and standard deviations, in Kgf, were: A - 66,31(10,24); B - 64,53 (20,40); C - 75,23 (11,84) and D - 66,62 (13,81). The data were submitted to ANOVA (p=0,13). The results indicated that it did not have statistical significant difference between the groups</span><span style="font-size: medium;">   </span><span style="font-size: medium;">A, B, C and D concluding that the speed in this type of test, with this device, can be varied without modify results.</span></p>


2009 ◽  
Vol 10 (5) ◽  
pp. 1-7 ◽  
Author(s):  
Peter Yaman ◽  
Jose Vivas ◽  
George Taylor

Abstract Aim This study compared the shear bond strength (SBS) and flexural strength (FS) of repaired interfaces using three techniques of surface preparation and repair of a micro-hybrid composite. Methods and Materials Composite specimens for SBS tests (n=36: diameter=8 mm, thickness=3 mm) for repair were shaped in a metal mold, visible-light cured, and embedded in dental stone. Composite specimens for FS tests (n=36: 2 mm × 2 mm × 12.5 mm) for repair were shaped in a silicone mold. Three different methods of surface preparation were evaluated: Group A (control) specimens were treated by etching with 35% phosphoric acid; Group B specimens were airabraded with 50 μm aluminum oxide at 100 psi; and Group C specimens received two parallel, 1 mm-deep grooves using a #¼.-round bur before being treated by etching with 35% phosphoric acid. After surface treatment, a bonding agent was placed on each specimen, which was then light cured. Repairs were accomplished by adding more composite to the SBS or FS specimens. Specimens were thermocycled 500 times between 5°C and 55°C with 30-second dwell times. All specimens were tested by loading to failure at a rate of 0.5 mm/min using an Instron Universal Testing Machine. Results Mean SBSs in MPa were: Group A=24.5 +4.4, Group B=28.5 +4.3, and Group C=27.0 +2.8. Mean FSs (MPa) were: Group A=60.5 +9.9, Group B=73.9 +13.2 and Group C=81.3 +14.3. For the FS tests, Group B and C were significantly different than Group A, but Group C was not significantly different than group B. For the SBS test, Group B was significantly different than Group A, but Group C was not significantly different. Conclusion Acid-etching alone was not very effective in producing well-bonded composite repairs (only 55% of the FS of normal microhybrid composite). Mechanical retention was more effective (SBS, FS) than acid-etching and as effective (SBS) or more effective (FS) than air-abrasion (p<0.05) for repaired composite specimens. Clinical Significance Either mechanical retention or air abrasion is recommended prior to repairing an existing composite restoration to achieve the highest bond strength. Citation Vivas J, Yaman P, Taylor G. Effect of Different Surface Treatments on the Shear and Flexural Re-bond Strengths of a Micro-hybrid Composite. J Contemp Dent Pract [Internet]. 2009 Sept; 10(5). Available from: http://www. thejcdp.com/journal/view/effectof-differentsurface- treatments-on-the-shear-and-flexural-rebond- st.


2019 ◽  
Vol 10 (3) ◽  
pp. 536-551
Author(s):  
Heidi Amezcua Hempel ◽  
María Salud Rubio Lozano ◽  
Eliseo Manuel Hernández Baumgarten ◽  
Pablo Correa Girón † ◽  
Oscar Torres Ángeles ◽  
...  

The study was to determine the presence of Classical Swine Fever virus (CSFv), in the meat of vaccinated pigs with the PAV-250 strain and then challenged using the same strain. Five treatment groups were established (each with four pigs). Group A: Pigs thatwere fed with processed hams from negative animals; Group B: Pigs that were fed with processed hams from commercial pigs inoculated with the ALD (reference strain) (titre of 104.0/ml); Group C: Pigs fed with processed hams from pigs infected with the virulent ALD strain (titre of 102.5/ml); Group D: Pigs fed with processed hams from pigs vaccinated with the PAV-250 strain and challenged with the ALD strain (titre of 101.1/ml); and Group E: Pigs fed with processed hams from pigs vaccinated with two doses of the PAV-250 strain and challenged with the ALD strain (negative). Blood samples were taken at d 1, 5, 10, 15 and 20 for biometric analysis. Groups B, C and D manifested clinical signs of CSFv: 40 °C temperature, anorexia, paralysis, vomiting, diarrhea, tremor, hirsute hair and cyanosis. Pigs were slaughtered and necropsies performed to identify lesions in tissues. Results of direct immunofluorescence testing of tissues were positive and the virus was recovered. Under these study conditions, it was found that CSFv resisted the cooking method at 68 °C for 40 min in hams from unvaccinated pigs, and that the virus was able to transmit the disease to healthy unvaccinated pigs, whereas the hams from the vaccinated animals did not transmit the virus.


Obesity Facts ◽  
2021 ◽  
pp. 1-9
Author(s):  
Serdar Sahin ◽  
Havva Sezer ◽  
Ebru Cicek ◽  
Yeliz Yagız Ozogul ◽  
Murat Yildirim ◽  
...  

<b><i>Introduction:</i></b> The aim of this was to describe the predictors of mortality related to COVID-19 infection and to evaluate the association between overweight, obesity, and clinical outcomes of COVID-19. <b><i>Methods:</i></b> We included the patients &#x3e;18 years of age, with at least one positive SARS-CoV-2 reverse transcriptase-polymerase chain reaction. Patients were grouped according to body mass index values as normal weight &#x3c;25 kg/m<sup>2</sup> (Group A), overweight from 25 to &#x3c;30 kg/m<sup>2</sup> (Group B), Class I obesity 30 to &#x3c;35 kg/m<sup>2</sup> (Group C), and ≥35 kg/m<sup>2</sup> (Group D). Mortality, clinical outcomes, laboratory parameters, and comorbidities were compared among 4 groups. <b><i>Results:</i></b> There was no significant difference among study groups in terms of mortality. Noninvasive mechanical ventilation requirement was higher in group B and D than group A, while it was higher in Group D than Group C (Group B vs. Group A [<i>p</i> = 0.017], Group D vs. Group A [<i>p</i> = 0.001], and Group D vs. Group C [<i>p</i> = 0.016]). Lung involvement was less common in Group A, and presence of hypoxia was more common in Group D (Group B vs. Group A [<i>p</i> = 0.025], Group D vs. Group A [<i>p</i> &#x3c; 0.001], Group D vs. Group B [<i>p</i> = 0.006], and Group D vs. Group C [<i>p</i> = 0.014]). The hospitalization rate was lower in Group A than in the other groups; in addition, patients in Group D have the highest rate of hospitalization (Group B vs. Group A [<i>p</i> &#x3c; 0.001], Group C vs. Group A [<i>p</i> &#x3c; 0.001], Group D vs. Group A [<i>p</i> &#x3c; 0.001], Group D vs. Group B [<i>p</i> &#x3c; 0.001], and Group D vs. Group C [<i>p</i> = 0.010]). <b><i>Conclusion:</i></b> COVID-19 patients with overweight and obesity presented with more severe clinical findings. Health-care providers should take into account that people living with overweight and obesity are at higher risk for COVID-19 and its complications.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1510.1-1511
Author(s):  
T. Kuga ◽  
M. Matsushita ◽  
K. Tada ◽  
K. Yamaji ◽  
N. Tamura

Background:Cardiovascular disease (CVD) is detected in up to 50% of systemic lupus erythematosus (SLE) patients1and major cause of death2. Even clinically silent SLE patients can develop left ventricular (LV) diastolic dysfunction3. Proper echocardiographic follow up of SLE patients is required.Objectives:To clarify how the prevalence of LV abnormalities changes over follow-up period and identify the associated clinical factors, useful in suspecting LV abnormalities.Methods:29 SLE patients (24 females and 5 men, mean age 52.8±16.3 years, mean disease duration 17.6±14.5 years) were enrolled. All of them underwent echocardiography as the baseline examination and reexamined over more than a year of follow-up period(mean 1075±480 days) from Jan 2014 to Sep 2019. Patients complicated with pulmonary artery hypertension, deep venous thrombosis or pulmonary embolism and underwent cardiac surgery during the follow-up period were excluded. Left ventricular(LV) systolic dysfunction was defined as ejection fraction (EF) < 50%. LV diastolic dysfunction was defined according to ASE/EACVI guideline4. LV dysfunction (LVD) includes one or both of LV systolic dysfunction and LV diastolic function. Monocyte to HDL ratio (MHR) was calculated by dividing monocyte count with HDL-C level.Prevalence of left ventricular abnormalities was analysed at baseline and follow-up examination. Clinical characteristics and laboratory data were compared among patient groups as follows; patients with LV dysfunction (Group A) and without LV dysfunction (Group B) at the follow-up echocardiography, patients with LV asynergy at any point of examination (Group C) and patients free of LV abnormalities during the follow-up period (Group D).Results:At the baseline examination, LV dysfunction (5/29 cases, 13.8%), LV asynergy (6/29 cases, 21.7%) were detected. Pericarditis was detected in 7 patients (24.1%, LVD in 3 patients, LV asynergy in 2 patients) and 2 of them with subacute onset had progressive LV dysfunction, while 5 patients were normal in echocardiography after remission induction therapy for SLE. At the follow-up examination, LV dysfunction (9/29 cases, 31.0%, 5 new-onset and 1 improved case), LV asynergy (6/29 cases, 21.7%, 2 new-onset and 2 improved cases) were detected. Though any significant differences were observed between Group A and Group B at the baseline, platelet count (156.0 vs 207.0, p=0.049) were significantly lower in LV dysfunction group (Group A) at the follow-up examination. Group C patients had significantly higher uric acid (p=0.004), monocyte count (p=0.009), and MHR (p=0.003) than Group D(results in table).Conclusion:LV dysfunction is progressive in most of patients and requires regular follow-up once they developed. Uric acid, monocyte count and MHR are elevated in SLE patients with LV asynergy. Since MHR elevation was reported as useful marker of endothelial dysfunction5, our future goal is to analyse involvement of monocyte activation and endothelial dysfunction in LV asynergy of SLE patients.References:[1]Doria A et al. Lupus. 2005;14(9):683-6.[2]Manger K et al. Ann Rheum Dis. 2002 Dec;61(12):1065-70.[3]Leone P et al. Clin Exp Med. 2019 Dec 17.[4]Nagueh SF et al. J Am Soc Echocardiogr. 2016 Apr;29(4):277-314.[5]Acikgoz N et al. Angiology. 2018 Jan;69(1):65-70.Numbers are median (interquartile range), Mann-Whitney u test were performed, p value less than 0.05 was considered statistically significant.Disclosure of Interests: :None declared


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Fei Huo ◽  
Hansheng Liang ◽  
Yi Feng

Abstract Background Pernicious placenta previa (PPP) can increase the risk of perioperative complications. During caesarean section in patients with adherent placenta, intraoperative blood loss, hysterectomy rate and transfusion could be reduced by interventional methods. Our study aimed to investigate the influence of maternal hemodynamics control and neonatal outcomes of prophylactic temporary abdominal aortic balloon (PTAAB) occlusion for patients with pernicious placenta previa. Methods This was a retrospective study using data from the Peking University People’s Hospital from January 2014 through January 2020. Clinical records of pregnant women undergoing cesarean section were collected. Patients were divided into two groups: treatment with PTAAB placement (group A) and no balloon placement (group B). Group A was further broken down into two groups: prophylactic placement (Group C) and balloon occlusion (group D). Results Clinical records of 33 cases from 5205 pregnant women underwent cesarean section were collected. The number of groups A, B, C, and D were 17, 16, 5 and 12.We found that a significant difference in the post-operative uterine artery embolism rates between group A and group B (0% vs.31.3%, p = 0.018). There was a significant difference in the Apgar scores at first minute between group A and group B (8.94 ± 1.43 vs 9.81 ± 0.75,p = 0.037),and the same significant difference between two groups in the pre-operative central placenta previa (29.4% vs. 0%,p = 0.044), complete placenta previa (58.8% vs 18.8%, p = 0.032),placenta implantation (76.5% vs 31.3%, p = 0.015). We could also observe the significant difference in the amount of blood cell (2.80 ± 2.68vs.10.66 ± 11.97, p = 0.038) and blood plasma transfusion (280.00 ± 268.32 vs. 1033.33 ± 1098.20, p = 0.044) between group C and group D. The significant differences in the preoperative vaginal bleeding conditions (0% vs 75%, p = 0.009), the intraoperative application rates of vasopressors (0% vs. 58.3%, p = 0.044) and the postoperative ICU (intensive care unit) admission rates (0% vs. 58.3%, p = 0.044) were also kept. Conclusions PTAAB occlusion could be useful in reducing the rate of post-operative uterine artery embolism and the amount of transfusion, and be useful in coping with patients with preoperative vaginal bleeding conditions, so as to reduce the rate of intraoperative applications of vasopressors and the postoperative ICU (intensive care unit) admission. In PPP patients with placenta implantation, central placenta previa and complete placenta previa, we advocate the utilization of prophylactic temporary abdominal aortic balloon placement.


Sign in / Sign up

Export Citation Format

Share Document