scholarly journals Comparison of Opening Torque of Grooved and Non-grooved Memory Alloy Screws for Mandibular Fracture Fixation

2014 ◽  
Vol 6 (2) ◽  
pp. 54-59
Author(s):  
Bijan Movahhedian ◽  
Shadab Ghods ◽  
Anahita Azadi ◽  
Mahdi Kadkhodazadeh

Background and aims. The aim of this study was to assess the opening torque of grooved and non-grooved screws made of shape memory alloys (SMA) for fixation of mandibular fractures. Materials and methods. In this in vitro study the opening torques of ten SMA screws with grooves and ten SMA screws without grooves were compared in 20 holes (10 holes for grooved screws and 10 holes for non-grooved screws) placed in the bovine mandible. Statistical significance was set at P < 0.05. Results. The mean opening torque was 2.27 ± 0.43 nm for screws in the control group and 2.05 ± 0.45 nm for screws in the grooved group (P < 0.05, P = 0.08). Conclusion. This study revealed that the torque needed for opening the grooved screws was higher in comparison with current fixation screws; however, the difference was not statistically significant.

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Rennaly de Freitas Lima ◽  
Érika Ponchet Alves ◽  
Pedro Luiz Rosalen ◽  
Ana Lúcia Tasca Gois Ruiz ◽  
Marta Cristina Teixeira Duarte ◽  
...  

The aim of the present study was to perform anin vitroanalysis of the antimicrobial and antiproliferative potential of an extract fromAnadenanthera colubrina(Vell.) Brenan (angico) and chemically characterize the crude extract. Antimicrobial action was evaluated based on the minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration, and the inhibition of formation to oral biofilm. Cell morphology was determined through scanning electron microscopy (SEM). Six strains of tumor cells were used for the determination of antiproliferative potential. The extract demonstrated strong antifungal activity againstCandida albicansATCC 18804 (MIC=0.031 mg/mL), with similar activity found regarding the ethyl acetate fraction. The extract and active fraction also demonstrated the capacity to inhibit the formation ofCandida albicansto oral biofilm after 48 hours, with median values equal to or greater than the control group, but the difference did not achieve statistical significance(P>0.05). SEM revealed alterations in the cell morphology of the yeast. Regarding antiproliferative activity, the extract demonstrated cytostatic potential in all strains tested. The present findings suggest strong antifungal potential forAnadenanthera colubrina(Vell.) Brenan as well as a tendency toward diminishing the growth of human tumor cells.


2020 ◽  
Vol 10 (1) ◽  
pp. 119-131
Author(s):  
Wafaa Mohammed Abed ◽  
Mohammed Oda Selman

To explore whether dual triggering for final oocyte maturation using a low dose of recombinant human chorionic gonadotropin (hCG) plus gonadotropin-releasing hormone agonist (GnRH-a) is as effective as the standard dose of recombinant hCG triggering alone in term of a total number of retrieved oocytes, fertilization and pregnancy rate in fresh autologous antagonist intracytoplasmic sperm injection (ICSI) cycles. 80 infertile women undergoing ICSI, aged ˂ 40 years, 18˂ Body mass index ˂30 Kg/m2 included in fresh autologous antagonist ICSI cycles. 40 women received a Standard dose of recombinant hCG (500 µg) alone and 40 women received GnRH-a (0.2 mg triptorelin plus 250 µg recombinant hCG) were used for final oocytes maturation. This study was conducted at the High Institute for Infertility Diagnosis and Assisted Reproductive Techniques, Al Nahrain University. The mean total number of retrieved oocytes, fertilization, and pregnancy rate were measured. The mean total oocyte number being statistically higher in the dual trigger group. The mean number of fertilized oocytes and clinical pregnancy rates was higher in the dual trigger group than in the control group, but the difference showed borderline statistical significance. Furthermore, fertilization rates show no statistical difference between the control group and the dual trigger group. Results of the study confirm that dual triggers show favorable improvement in fresh autologous antagonist ICSI cycles with the use of GnRH agonists plus hCG compared with hCG alone for triggering of final oocyte maturation.


2022 ◽  
Vol 10 (19) ◽  
pp. 29-33
Author(s):  
Sebastián M. Ulloa-Alvarez ◽  
María E. Guerrero-Coello ◽  
José E. Torracchi-Carrasco

Introduction: Endodontic retreatment seeks reentry to the root canal system to remove all filling material, identification and correction of pathological or iatrogenic defects. Objective: This study aimed to compare the dissolving capacity of eucalyptus oil, orange oil, and distilled water versus three types of endodontic cements. Materials and methods: Two hundred and four stainless steel molds were fabricated, where each cement sample was placed to the edge and left to set in the incubator, simulating normal oral conditions for 7 days. Subsequently, the solubility of each cement was analysed by immersing the samples in eucalyptus and orange oil for ten minutes in a static and ultrasonic environment. The solubility of the cement was evidenced by the difference between the weight before and after contact with the oils, data were statistically analysed with the ANOVA test and the post hoc Tukey bootstrap means test with 1,000 repetitions. Results: The control group and eucalyptus oil having no significant effect (p>0.05), the ultrasonic environment was found to be effective (p<0.05), whereas orange oil had better dissolution effects (p=0.004). Conclusions: The most susceptible cement was Sealapex, while the least soluble was MTA-Fillapex in all the solvents studied.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3543
Author(s):  
Marco Tallarico ◽  
Aurea Lumbau ◽  
Roberto Scrascia ◽  
Gianluca Demelas ◽  
Franco Sanseverino ◽  
...  

Background: Intraoral scanners (IOSs) in implantology represent a viable approach for single teeth or partial arches. However, when used for complete edentulous arches or long-span edentulous areas, it has been demonstrated that there is a need for improvement of IOS-related techniques. Therefore, the aim of this in vitro study was to assess the trueness and precision of a complete arch digital impression on four and six implants taken with or without a customized, prosthetic-based impression template. Materials and Methods: Two experimental models were prepared, representative of a complete edentulous mandible restored with four and six implants with built-in scan abutments. Models were scanned with (test group, TG) or without (control group, CG) the prosthetic-based impression template. Eight scans were taken for each model. The time needed to take impressions, error, trueness, and precision were evaluated. A statistical analysis was performed. Results: In the case of four implants, the time needed for the impression was 128.7 ± 55.3 s in the TG and 81.0 ± 23.5 s in the CG (p = 0.0416). With six scan abutments, the time was 197.5 ± 26.8 and 110.6 ± 25.2 s in the TG and CG, respectively (p = 0.0000). In the TG, no errors were experienced, while in the CG, 13 impressions were retaken due to incorrect stitching processes. In the four-implant impression, the mean angle deviation was 0.252 ± 0.068° (95% CI 0.021–0.115°) in the CG and 0.134 ± 0.053° (95% CI 0.016–0.090°) in the TG. The difference was statistically significant (p = 0.002). In the six-implant impression, the mean angle deviation was 0.373 ± 0.117° (95% CI 0.036–0.198°) in the CG and 0.100 ± 0.029° (95% CI 0.009–0.049°) in the TG (p = 0.000). In the TG, there were no statistically significant differences in the mean angle deviation within the group (p > 0.05), but there were in the CG. A colorimetric analysis showed higher deviations from the original model for the six-implant impression without a prosthetic template. Conclusions: Although all of the impressions exhibited deviation from the original model in the range of clinical acceptability, the prosthetic-based impression template significantly improved the trueness and precision of complete edentulous arches rehabilitated with four or six implants, making the complete arch digital impression more predictable.


2016 ◽  
Vol 21 (1) ◽  
pp. 83-88
Author(s):  
Marcelo Faria da Silva ◽  
Célia Regina Maia Pinzan-Vercelino ◽  
Júlio de Araújo Gurgel

Objective: The aim of this in vitro study was to evaluate the deflection-force behavior of nickel-titanium (NiTi) orthodontic wires adjacent to the portion submitted to heat treatment. Material and Methods: A total of 106 segments of NiTi wires (0.019 x 0.025-in) and heat-activated NiTi wires (0.016 x 0.022-in) from four commercial brands were tested. The segments were obtained from 80 archwires. For the experimental group, the distal portion of each segmented archwire was subjected to heat treatment (n = 40), while the other distal portion of the same archwire was used as a heating-free control group (n = 40). Deflection tests were performed in a temperature-controlled universal testing machine. Unpaired Student's t-tests were applied to determine if there were differences between the experimental and control groups for each commercial brand and size of wire. Statistical significance was set at p < 0.05. Results: There were no statistically significant differences between the tested groups with the same size and brand of wire. Conclusions: Heat treatment applied to the distal ends of rectangular NiTi archwires does not permanently change the elastic properties of the adjacent portions.


2019 ◽  
Vol 13 (03) ◽  
pp. 318-322 ◽  
Author(s):  
Imran Farooq ◽  
Saqib Ali ◽  
Intisar Ahmad Siddiqui ◽  
Khalifa S. Al-Khalifa ◽  
Mohammed Al-Hariri

Abstract Objective The aim of this study was to assess changes in micro-hardness level of enamel after it was exposed to thymoquinone (TQ). Materials and Methods Sixteen enamel blocks were prepared and divided into two groups (each group received eight blocks, n = 8); Gp 1 (control): enamel blocks kept in 100 mL artificial saliva (AS) for 24 hours and Gp 2: enamel blocks kept in a mixture of TQ powder (1 g) and AS (100 mL) for 24 hours. Post-immersion they were subjected to simulated brushing with each sample receiving 8,000 linear strokes. For brushing, 3 mL of AS and TQ oil was used for groups 1 and 2, respectively. Enamel surfaces were analyzed for changes in values of surface micro-hardness (pre-immersion, post-immersion, and post-brushing) by obtaining Vickers hardness number (VHN). Results The present study indicated improvement in micro-hardness levels for both groups although experimental group showed more enhancement. The mean baseline VHN for control group was 498.6, 500.4 for post-immersion, and 503.5 for post-brushing. The mean baseline VHN for experimental group was 448.7, 531 for post-immersion, and 610.3 for post-brushing. Statistically significant differences (p < 0.05) were observed when post-brushing VHN values of both groups were compared and also within the experimental group when post-brushing values were compared with baseline values. Statistical Analysis Wilcoxon signed-rank test was applied for the evaluation of pre- and post-exposure hardness values. Level of significance was ≤0.05. Conclusion The exposure of enamel to TQ led to an improvement in its micro-hardness levels. Further studies are required to understand the mechanism of action of TQ on human tissues.


2018 ◽  
Vol 12 (02) ◽  
pp. 237-241
Author(s):  
Seyed Amir Mousavi ◽  
Alireza Farhad ◽  
Shirin Shahnaseri ◽  
Abbas Basiri ◽  
Erfan Kolahdouzan

ABSTRACT Objective: The apical constriction (AC) and the apical foramen (AF) are the principal reference points used to determine the apical limit for instrumentation and root canal filling. AC varies in different races, and the aim of the current study was to measure and compare the distances from AC to AF and the anatomical apex (AA) in incisor and molar teeth in the Iranian population. Materials and Methods: Forty-five roots of incisor teeth and 45 roots of molar teeth were selected randomly in Isfahan Province, Iran. If the foramen was located toward the mesial or distal side of the apex, the cut was made mesiodistally, and if it was toward the buccal or lingual side, the section was made accordingly. Roots were examined under a microscope at ×25 magnification. The distances from AC to AF and AA were then estimated using a Motic camera. Descriptive statistics were used. The independent t-test was also used to compare distances in incisors and molars, and P = 0.05 was deemed to indicate statistical significance. Results: The mean distances between AC and AF were 0.847 ± 0.33 mm in incisors and 0.709 ± 0.27 mm in molars. The mean distances between AC and AA were 1.23 ± 0.39 mm in incisors and 1.01 ± 0.38 mm in molars. In an independent t-test, the distances between AC and AF differed significantly in incisors and molars (P = 0.035), but the distances between AC and AA did not (P = 0.172). Conclusion: The end points for root canal therapy should be 0.85 mm in incisors and 0.70 mm in molars.


2012 ◽  
Vol 36 (4) ◽  
pp. 369-371 ◽  
Author(s):  
M Mirkarimi ◽  
M Bargrizan ◽  
S Eskandarion ◽  
M Shahsavari

Objective: The aim of this study was to assess the effect of zinc sulfate on microhardness of human primary enamel. Method: Sixteen sound primary molars were sectioned mesiodistally. For each sample one of the sections was randomly immersed in artificial saliva (Biotene,USA) and the other was immersed in artificial saliva which was charged with 10 mg/5mL concentration of zinc sulfate supplement (Razak Company, Iran) daily. After 24 days (the expected time to use up one 120-mL bottle) the surface microhardness of enamel was measured by knoop hardness test (KH) with Knoop diamond under a 50-gram load for 10 seconds. Results: The mean (± SD) microhardness values (KHV) for the tested groups were 320 ± 49.45 and 357 ± 36.35, respectively. There were statistically significant differences between the groups as exhibited by independent t-test (P=0.023). Conclusion: Primary teeth immersed in a zinc sulfate rich solution for 24 days showed higher microhardness values in comparison with the control group.


Author(s):  
Praneetha D Rani ◽  
Vijaya Hegde

Introduction: Fluoride toothpastes are a major reason for the decline in dental caries globally. For fluoride toothpaste to be effective, an adequate amount of Total Soluble Fluoride (TSF) must be available in the toothpastes. Aim: To determine and compare the Total Fluoride (TF), TSF and pH among various toothpaste brands. Materials and Methods: An in-vitro study was conducted during October 2019 on 20 toothpaste samples, which belonged to four groups namely, herbal toothpastes group, nonherbal toothpastes group, medicated toothpastes group and kids toothpastes group. Analysis of the samples was done at the Department of Environmental Engineering Laboratory, National Institute of Technology, Surathkal, Karnataka, India. The TF and the TSF concentration was determined using fluoride ion electrode. The pH was determined using pH meter. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS version 19.0). Analysis of variance (ANOVA) was used by Tukey’s post-hoc test to determine the difference between groups. The level of significance was kept at 0.05. Results: The results showed that there was a significant difference between the toothpaste types for mean TF concentration (p=0.004). The post-hoc test showed that there was a significant difference between herbal and nonherbal toothpastes (p=0.041) where the mean TF concentration for nonherbal toothpastes was 1095.20 ppm when compared to herbal toothpastes was 704.40 ppm. The results showed that there was a siginificant difference between the toothpaste types for Mean TSF concentration (p<0.003). There was a significant difference between medicated and kids toothpastes (p=0.024) where the mean total soluble fluoride concentration for medicated toothpastes was 938.60 ppm when compared to the kids toothpastes was 521.20 ppm. Conclusion: The present study showed that pH of all the toothpastes were either neutral or alkaline and the TSF concentration was less when compared to TF concentrations.


2010 ◽  
Vol 1 (3) ◽  
pp. 163-166
Author(s):  
Shelly Ahuja

ABSTRACT Introduction The major cellular events in the tissue repair are mitogenesis, migration and metabolism. The proteins responsible for coordination of these events are called “growth factors”. The activated platelets at the wound margins release several growth factors, such as PDGF, TGF-β and EGF, etc., and plasma exudates also provide an important source of TGF-β factors. Materials and methods Periodontal ligament fibroblast obtained from third molar impaction surgery, periodontal ligaments were cultured under standard conditions and spread on 96 well tissue culture plates. Platelet concentrate was obtained after centrifugation of 350-400 ml of blood at 1000 and 5000 rpm. 15 μl of platelet concentrate was added to each well. The proliferation rate of test and control group was determined by Redox indicator (Alamar blue® assay). The number of cells were counted by neu bar counting chamber after 24, 48 and 72 hours. Results The proliferation activity of cells was considerably higher in the platelet concentrate group (test group) than the control group. The difference was highly significant upto 72 hours after addition of platelet concentrates (Mann-Whitney U test p < 0.001). Conclusion A cellular effect of the platelet concentrate is clearly discernible. It was concluded that the use of platelet concentrate is an effective modality of regeneration.


Sign in / Sign up

Export Citation Format

Share Document