scholarly journals Effect of Bleaching Agents on the Flexural Strength of Bovine Dentin

2014 ◽  
Vol 15 (5) ◽  
pp. 552-555 ◽  
Author(s):  
Ricardo Danil Guiraldo ◽  
Sandra Kiss Moura ◽  
Sandrine Bittencourt Berger ◽  
Rafaela Pazenhagen ◽  
Natan Martinelli ◽  
...  

ABSTRACT The aim of this study was to evaluate the effect of bleaching on the flexural strength of bovine dentin, using bleaching agents containing calcium (Whiteness HP Blue and Whiteness Class) and not containing calcium (Whiteness HP and Whiteness Perfect). Sixty bovine incisor tooth slices were obtained and divided into five experimental groups (n = 12), such as G1, untreated control group; G2, Whiteness HP Max [35% hydrogen peroxide (HP)]; G3, Whiteness HP Blue (35% HP); G4, Whiteness Class (7.5% HP) and G5, Whiteness Perfect (22% carbamide peroxide). Samples were submitted to bleaching treatment according to the manufacturers’ instructions. The control group remained in artificial saliva during bleaching. After bleaching, the enamel was removed and dentin specimens (7 mm length × 1.7 mm width × 0.5 mm thickness) were prepared. Samples were tested in a universal testing machine (EMIC). Data were analyzed by analysis variance (ANOVA) and Tukey's test. Differences between the groups were identified by ANOVA. The mean values (± standard deviation) for the experimental groups, such as (in MPa) G1 = 19.05 ± 2.68 a; G2 = 12.69 ± 4.52 b; G3 = 16.39 ± 3.74 ab; G4 = 14.90 ± 5.60 ab; and G5 = 12.71 ± 2.25 b. Groups with the same lowercase letter were significantly different from each other. The presence of calcium in bleaching agents appeared to influence the flexural strength of bovine dentin after bleaching treatment, for both office bleaching (35% HP) and home bleaching (7.5% HP). How to cite this article Berger SB, Pazenhagen R, Martinelli N, Moura SK, de Carvalho RV, Guiraldo RD. Effect of Bleaching Agents on the Flexural Strength of Bovine Dentin. J Contemp Dent Pract 2014;15(5):552-555.

2007 ◽  
Vol 8 (3) ◽  
pp. 21-28 ◽  
Author(s):  
Marjaneh Ghavamnasiri ◽  
Sara Abedini LNU ◽  
Alireza Mahdizadeh Tazangi

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.


2018 ◽  
Vol 11 (3) ◽  
pp. 1573-1581 ◽  
Author(s):  
Maha M. Turki ◽  
Faiza M. Abdul-Ameer

Scleral acrylic resin is widely used to synthesize ocular prosthesis. However, the properties of this material change over time, thus requiring the prosthesis to be refabricated. Many studies were conducted to improve these properties by reinforcing this material with nanoparticles. This study aims to evaluate the effect of silver nanoparticle powder on the mechanical properties (transverse flexural strength, impact strength, shear bond strength, surface microhardness, and surface roughness) of scleral acrylic resin used for ocular prostheses. Two concentrations were selected from the pilot study and evaluated for their effects on scleral acrylic resin properties. According to the pilot study, 0.01 and 0.02wt% AgNPs powder improved the transverse flexural strength, microhardness, and surface roughness compared with other percentages. The specimens in the main study were divided into (3) main groups, (50) specimens without additives (control group A), (50) experimental specimens (with 0.01wt% AgNPs group B), and (50) experimental specimens (with 0.02 wt% AgNPs group C). Each group was subdivided into (5) equal subgroups depending on the tests used. The data were studied using one way ANOVA and post hoc LSD test. At 0.01 wt% AgNPs addition, the mean values of transverse flexural strength insignificantly increased (p> 0.05), and those of impact strength and shear bond strength significantly increased (p< 0.05) compared with those of the control group. At 0.02 wt% AgNPs addition (group C), the mean value of transverse flexural strength significantly increased (p< 0.05), that of impact strength insignificantly increased (p> 0.05), and that of shear bond strength increased with high significance (p< 0.01) compared with those of the control group. Group C showed insignificant increase in the mean values of transverse flexural strength, impact strength, and shear bond strength (p. 0.05) compared with group B. The scleral acrylic resin added with 0.01 and 0.02 wt% AgNPs showed insignificant increase in microhardness and insignificant decrease in surface roughness. The addition of AgNPs powder in both concentrations improved the mechanical properties of scleral acrylic resin used for ocular prostheses.


2015 ◽  
Vol 1 (3) ◽  
pp. 143
Author(s):  
Diatri Nari Ratih

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.   


Author(s):  
Ashraf Albrakati

Tramadol, a broadly in recent years, is an effective analgesic agent for the treatment of moderate to acute pain. Its metabolites are excreted by the kidney which may cause nephrotoxicity. Moringa oleifera leaves are commonly used to provide herbal and plant-derived medicinal products especially in developing nations. The present study was carried out to determine the biochemical and histopathological changes in the kidney of tramadol-treated albino mice and to evaluate the possible protective role of Moringa oleifera leaves against tramadol-induced nephrotoxicity. Twenty adult albino mice were divided into four groups. Control group (group i) received daily intraperitoneal injection of normal saline only, group ii received oral dose of Moringa oleifera leaves extract (20 mg/kg/bw) for three weeks, group iii received daily intraperitoneal dose of tramadol (0.3 mg/kg/bw) for the same period, group iv, received daily oral dose of Moringa oleifera leaves extract, (20 mg/kg/bw) three hours before injecting intraperitoneal dose of tramadol (0.3 mg/kg/bw), for the same period. Blood samples were withdrawn at the end of the experiment for kidney function tests and specimens from the kidney were processed for histological study. No significant differences in the mean values of the kidney function tests were noticed between Moringa oleifera group and control group. However, there was highly significant increase in the mean values of serum, urea and creatinine in tramadol-treated group as compared to the control group. Although tramadol + Moringa oleifera group revealed significant difference in the mean values of urea and creatinine when compared with tramadol-treated group. So, Moringa oleifera leaves extract have been shown to attenuate the renal dysfunction, improve the renal architecture, with nearly normalization of serum urea and creatinine levels which indicate improvement of renal function. In conclusion, in the light of biochemical results and histological findings, co-administration of Moringa oleifera leaves lessened the negative effects of tramadol-induced nephrotoxicity; possibly by its antioxidant action. Further investigation of these promising protective effects of Moringa oleifera leaves against tramadol-induced renal injury may have considerable impact on developing an adjunct therapy aiming to improve the therapeutic index of some nephrotoxic drugs.


2021 ◽  
pp. 036354652098781
Author(s):  
Mathias Paiva ◽  
Lars Blønd ◽  
Per Hölmich ◽  
Kristoffer Weisskirchner Barfod

Background: Tibial tubercle–trochlear groove (TT-TG) distance is often used as a measure of lateralization of the TT and is important for surgical planning. Purpose: To investigate if increased TT-TG distance measured on axial magnetic resonance images is due to lateralization of the TT or medialization of the TG. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 84 knees (28 normal [NK], 28 with trochlear dysplasia [TD], and 28 with patellar dislocation without TD [PD]) were examined. The medial border of the posterior cruciate ligament (PCL) was chosen as the central anatomic landmark. The distance from the TT to PCL (TT-PCL) was measured to examine the lateralization of the TT. The distance from the TG to the PCL (TG-PCL) was measured to examine the medialization of the TG. Between-group differences were investigated by use of 1-way analysis of variance. Results: The mean values for TT-TG distance were 8.7 ± 3.6 mm for NK, 12.1 ± 6.0 mm for PD, and 16.7 ± 4.3 mm in the TD group ( P < .01). The mean values for TT-PCL distance were 18.5 ± 3.6 mm for NK, 18.5 ± 4.5 mm for PD, and 21.2 ± 4.2 mm in the TD group ( P = .03). The mean values for TG-PCL distance were 9.6 ± 3.0 mm for NK, 7.1 ± 3.4 mm for PD, and 5.1 ± 3.3 mm in the dysplastic group ( P < .01). Conclusion: The present results indicate that increased TT-TG distance is due to medialization of the TG and not lateralization of the TT. Knees with TD had increased TT-TG distance compared with the knees of the control group and the knees with PD. The TT-PCL distance did not differ significantly between groups, whereas the TG-PCL distance declined with increased TT-TG.


2009 ◽  
Vol 28 (2) ◽  
pp. 116-121 ◽  
Author(s):  
Irena Kafeđiska ◽  
Dejan Spasovski ◽  
Todor Gruev ◽  
Mane Grličkov ◽  
Kočo Cakalaroski ◽  
...  

Association Between Osteoarticular Scores and Acute Phase Reactant Levels in Rheumatoid Arthritis The aim of this prospective control study was a quantitative evaluation of the activity of rheumatoid arthritis (RA) in certain time intervals, using articular indexes (set of 28 sensitive and 28 swollen joints), laboratory parameters (Hb, Hct, Er, Le and Plt) and acute phase reactants (ESR, RF, CRP); to determine which of the acute phase reactants is the most useful biochemical marker for the evaluation of disease activity in RA; to quantify the therapeutical and laboratory differences in certain time intervals in the group with and without immunomodulatory therapy with Methotrexate. Sixty patients with RA were included, 27 of who were treated with non-steroid antiinflammatory drugs (NSAIDs) and Methotrexate (MTX). The control group consisted of 33 patients treated only with NSAIDs because of irregular controls. In the first group of patients the disease activity was estimated at four time intervals, and in the control group of patients at three time intervals following the scores of the articular indexes, blood cell counts, ESR and CRP in every patient. In the first group of patients decreased activity of RA was found upon every following control with a consecutive decrease in mean values of the scores of articular indexes with statistically significant differences at the four time intervals. Considering laboratory parameters, there were statistically significant differences in the mean values of Hb, Er, Plt, ESR, (p=0.0462, p=0.0076, p= 0.0058, p= 0.0003). Mean values of CRP did not show statistically significant differences, but the number of patients who were CRP negative increased (there were great standard deviations). In the group of patients treated only with NSAIDs, there were statistically significant differences in the mean values of the scores of articular indexes with an increse at every following control (in favour of progression of the disease). There were no statistically significant differences considering blood cell counts, ESR and CRP (in favour of permanently active disease). In conclusion, CRP is the most useful marker for the prospective follow-up of patients with RA.


2007 ◽  
Vol 21 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Ana Cristina Soares Santos ◽  
André Tortamano ◽  
Sandra Regina Frazatto Naccarato ◽  
Gladys Cristina Dominguez-Rodriguez ◽  
Julio Wilson Vigorito

This in vitro study was designed to compare the forces generated by commercially available elastomeric chains and NiTi closed coil springs, and to determine their force decay pattern. Forty elastomeric chains and forty NiTi closed coil springs were divided into 4 groups according to the following manufacturers: (1) Morelli®, (2) Abzil®, (3) TP Orthodontics® and (4) American Orthodontics®. The specimens were extended to twice their original length and stored in artificial saliva at 37°C. Initial force was measured by means of an Instron universal testing machine and then at 1, 4, 7, 14, 21, and 28 days. The results revealed that the elastomeric chains delivered a mean initial force of 347 g for Morelli®, 351 g for American Orthodontics®, 402 g for Abzil®, and 404 g for TP Orthodontics®. The NiTi closed coil springs generated a mean initial force of 196 g for American Orthodontics®, 208 g for TP Orthodontics®, 216 g for Abzil®, and 223 g for Morelli®. The mean percentage of force decay observed after 28 days for the elastomeric chains was 37.4% for TP Orthodontics®, 48.1% for American Orthodontics®, 65.4% for Morelli®, and 71.6% for Abzil®. After 28 days, the NiTi closed coil springs presented a mean percentage of force decay of 22.6% for American Orthodontics®, 29.8% for Abzil®, 30.6% for Morelli®, and 45.8% for TP Orthodontics®. At the end of the study, significant differences were observed between the elastomeric chains and the NiTi closed coil springs. The results indicated that the studied NiTi closed coil springs are more adequate for dental movement than the elastomeric chains.


2020 ◽  
pp. 028418512093837
Author(s):  
Sunay Sibel Karayol ◽  
Kudret Cem Karayol

Background The aim of this study is to investigate the role of diffusion-weighted imaging (DWI) in the differential diagnosis of sacroiliitis. Purpose To compare the sacroiliac magnetic resonance imaging (MRI) examinations of patients with suspected active sacroiliitis with patients with acute SpA MR findings and the DWI examinations of patients with acute brucella sacroiliitis, and thereby determine whether DWI can contribute to the differential diagnosis. Material and Methods A total of 84 patients were included in the study and were separated into three groups: group 1 (13 women, 6 men) comprised cases with brucella positive for sacroiliitis; group 2 (17 women, 19 men) comprised cases negative for brucella but with sacroiliitis; and group 3 (16 women, 13 men) comprised cases negative for brucella and sacroiliitis. Results The mean bone marrow apparent diffusion coefficient (ADC) values independently of edema were determined as 0.71 × 10−3 in sacroiliitis and brucella-positive patients, as 0.53 × 10−3 in brucella-negative and sacroiliitis-positive patients, and as 0.43 × 10−3 in the control group of brucella-negative sacroiliitis-negative patients. In the ADC measurements taken from areas of evident edema in patients with sacroiliitis, the mean values were 0.13 × 10−3 in the brucella-positive group and 0.12 × 10−3 in the brucella-negative group. Conclusion By adding DWI, which is a rapid MR sequence, to sacroiliac joint MR examination, normal bone marrow and bone marrow with sacroiliitis can be objectively differentiated with ADC measurements in addition to visual evaluation.


2020 ◽  
Vol 10 (2) ◽  
pp. 82-86
Author(s):  
Mushtaq Hussain Lashari ◽  
Sumbel Sumera ◽  
Umer Farooq ◽  
Zia Ur Rehman ◽  
Nuzhat Sial ◽  
...  

Background: Health problem are culturally associated with smoking in developing countries. Many hazardous chemicals are taken up by direct or passive smoking causing lipid peroxidation resulting in oxidative stress. Objectives: To estimate the occurrence of smoking and its effects on the lipid profile in populations of Hasilpur, Pakistan. Methodology: The current study was conducted from April - August 2014. Out of 247 apparently healthy subjects of both genders (male=220; female=27), 134 were smokers and 113 were non-smokers. In order to analyze lipid profile, blood samples were collected in early morning hours from the selected members who were asked to fast all night. By using Chem-100 chemistry analyzer, cholesterol, triglyceride, HDL, LDL and VLDL were analyzed. Results: The overall prevalence of smokers was 54.25%. The results showed 60.9% prevalence in males and 0% in females. The mean value of serum triglyceride in control, light smokers and heavy smokers was 147.4±11.7mg/dl, 190.8±41.4 and 205.3±29.7mg/dl, respectively. The results of cholesterol in control, light smokers and heavy smokers were 147.38±7.99mg/dl, 136.8 ±12. 8mg/dl and 173.44±8.63mg/dl, respectively. There was a considerable distinction in the mean level of serum triglyceride and cholesterol between the control group, light smokers and heavy smoker groups (P<00.5). The mean value of HDL of control, light smokers and heavy smokers was 30.93±1.30mg/dl, 31.10±2.45 and 34.58±1.55mg/dl, respectively. The mean values of LDL and VLDL of control, light smokers and heavy smokers were 110.46±3.63mg/dl, 106.00±4.52mg/dl, 117.19±3.48mg/dl and 33.54±3.11mg/dl, 49±9.02mg/dl, 41.06±5.34mg/dl, respectively. There was significant difference in the mean level of HDL, LDL and VLDL between the control group, light smokers and heavy smoker groups (P<0.05). Conclusion: This study concluded that smoking is the reasons of variation in the lipid profile. Elevated period of smoking and the number of smoked cigarettes/day reason the alteration in serum lipid levels and is probably related with increased danger for coronary artery disease.


2004 ◽  
Vol 16 (2) ◽  
pp. 207 ◽  
Author(s):  
A. Castro Neto ◽  
B.V. Sanches ◽  
S.H.V. Perri ◽  
M.M. Seneda ◽  
J.F. Garcia

The aim of the present study was to evaluate the effects of uterine double flushing on embryo recovery rates (total structures and viable embryos), after a resting period with the uterus filled with PBS. There were 210 embryo recovery procedures conducted using the uterine double flushing method, and the results were compaired with 432 conventional single flushing procedures. All procedures were conducted with Limousin (n=403) and Guzerá (n=239) cows, following the same superovulation protocol. Cyclic donors received a progestagen implant (CIDR) and 1mL of oestradiol benzoate (Estrogin®) at Day 0. Between Day 5 and Day 9 animals received doses ranging from 200 to 300UI (zebu cows) and 300 to 500UI (taurine cows) of FSH (Pluset® – Serono) in decreasing doses. Between Day 6 and Day 8 PGF2a (Ciosin®) was administered, followed by withdrawal of the progestagen after 24h. Artificial insemination was performed between 14 and 26h after the beginning of treatment. For the double flushing procedure, after the first uterine flushing of both horns with 1L DPBS (Nutricell), a Foley catheter was positioned in the uterine body in order to fill the uterus with the same solution (80 to 150mL). After this procedure the catheter was closed with a disposable 5-mL syringe gasket, and the animals were allowed to rest in the surroundings of the work place for 30min. After this period, a second flush was performed in order to recover the remaning liquid used during manipulation of the uterus. Animals from the control group (group A) were subjected to a single uterine flushing procedure. From 210 double flushing procedures (group B – test), 1409 viable embryos were produced, classified as grades I, II, III and IV (IETS), (average of 6.7 embryos per procedure), whereas, in the 432 single flushing procedure (group A – control), 1993 embryos were produced (average of 4.6). Statistical analysis showed the increase of viable embryo recovery rate. When consecutive double flushing was performed, the average of recovered embryos increased from 8.3 to 12.7 (P&lt;0.05) in Limousin cows, and from 7.9 to 11.5 (P&lt;0.05) in Guzerá cows. Comparing recovery after single flushing with that after double flushing, the mean number of viable embryos increased from 4.7 to 6.9 (P&lt;0.05) in Limousin cows and from 4.5 to 6.4 (P&lt;0.05) in Guzerá cows. In order to assure the nonexistence of negligence effects or operator influence on results, the mean values of total embryo recovery rate after single flushing (control group) was compared to the mean values of the same rate after the first uterine flushing on test group. Results indicated no difference between recovery rates. The present work showed the viability of using the uterine double flushing procedure for improvement of embryo recovery rates in cattle.


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