scholarly journals Cyclic fatigue resistance of four different nickel-titanium instruments in an artificial canal

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 800
Author(s):  
Khoa Van Pham
Keyword(s):  
Stainless Steel ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Primary System ◽  
Group 4 ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
Number Of Cycles ◽  
Electronic Microscope

Introduction: The objective of this study was to measure the number of cycles to fracture of four continuous or reciprocating rotary nickel-titanium instruments in different materials. Methods: A total of 40 nickel-titanium instruments were used for the present study. Instruments were divided into four groups (n=10): group 1, Revo-S SU; group 2, ProTaper Next X2; group 3, Reciproc R25; group 4, WaveOne Gold Primary. An artificial stainless-steel was used to test the cyclic fatigue of the instruments. The instruments were introduced into the stainless-steel canal, one at a time, until they reached the other end, then they were rotated inside the canal without in-out motion. The time from the beginning of instrument rotation until the occurrence of breakage was recorded. The number of rotated cycles to fracture of the instrument were calculated based on the revolutions per minute (rpm) of each instrument and the recorded rotated time. The mean number of cycles to fracture and standard deviations were calculated and statistically analysed. Results: The number of cycles to fracture of the Revo-S SU was the lowest, and that of the WaveOne Gold Primary was highest. Scanning electronic microscope images of fracture surfaces revealed the characteristics of fatigue. Conclusions: The number of cycles to fracture of the reciprocating WaveOne Gold Primary system was the highest amongst the tested instruments.

scholarly journals Microleakage under Metallic and Ceramic Brackets Bonded with Orthodontic Self-Etching Primer Systems

2008 ◽  
Vol 78 (6) ◽  
pp. 1089-1094 ◽  
Author(s):  
Tancan Uysal ◽  
Mustafa Ulker ◽  
Sabri Ilhan Ramoglu ◽  
Huseyin Ertas
Keyword(s):  
Stainless Steel ◽  
Phosphoric Acid ◽  
White Spot Lesions ◽  
Group 4 ◽  
Ceramic Brackets ◽  
Group 3 ◽  
Group 2 ◽  
Ceramic Bracket ◽  
Acid Gel

Abstract Objective: To compare the in vitro microleakage of orthodontic brackets (metal and ceramic) between enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides produced by self-etching primer system with that of conventional acid etching and bonding. Materials and Method: Sixty freshly extracted human mandibular premolar teeth were used in this study. The teeth were separated into four groups of 15 teeth each and received the following treatments: Group 1, 37% phosphoric acid gel + Transbond XT liquid primer + stainless steel bracket; Group 2, Transbond Plus Self-Etching Primer (TSEP) + stainless steel bracket; Group 3, 37% phosphoric acid gel + Transbond XT liquid primer + ceramic bracket; Group 4, TSEP + ceramic bracket. After curing, specimens were further sealed with nail varnish, stained with 0.5% basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-adhesive and bracket-adhesive interfaces from both occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U tests. Results: The gingival sides in all groups exhibited higher microleakage scores compared with those observed in occlusal sides for both adhesive interfaces. Enamel-adhesive interfaces exhibited more microleakage than did the adhesive-bracket interfaces. Brackets bonded with self-etching primer system showed significantly higher microleakage at the enamel-adhesive interface of the gingival side. Conclusions: TSEP causes more microleakage between enamel-adhesive interfaces, which may lead to lower bond strength and/or white-spot lesions.

scholarly journals Resistance to Cyclic Fatigue of Nickel-Titanium Files Immersed in Sodium Hypochlorite at Body Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Hind F. Abuhulaibah ◽  
Ammar AbuMostafa
Keyword(s):  
Stainless Steel ◽  
Body Temperature ◽  
Sodium Hypochlorite ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Control Group ◽  
Significant Drop ◽  
Number Of Cycles ◽  
Post Hoc ◽  
One Way Anova

Background/purpose. To assess the resistance to cyclic fatigue (CF) displayed by two nickel-titanium (NiTi) files, One Curve (OC) and ProTaper Gold (PTG), after their immersion in 2.5% sodium hypochlorite (NaOCl) solution at body temperature. Materials and Methods. Forty-five files from each brand were randomly assigned to three groups (n = 15) and subjected to the following: no immersion (control), 1-minute immersion, and 5-minute immersion in 2.5% NaOCl at 37°C. CF for all the files was tested within a well-lubricated stainless-steel artificial canal in a water bath at 37°C simulating body temperature. The procedure was video recorded, and the number of cycles to fracture (NCF) was calculated by multiplying the time taken to fracture, with the number of rotations per second. The data were analyzed for normality, and thereafter, one-way ANOVA with multiple Bonferroni was used as the post hoc test. Results. The resistance to CF of OC files was significantly higher than PTG files in all groups. In groups immersed in NaOCl for one minute, OC files showed significant drop in the CF resistance; PTG files showed a drop as well but not significantly. Both files demonstrated a significant drop in resistance to CF after immersion in NaOCl for five minutes compared to the control group. Conclusion. OC files were significantly more resistant to CF compared to PTG in all groups. Immersion in 2.5% NaOCl for 5 minutes significantly reduced the resistance to CF for all the files.

scholarly journals Acute Phase Effect of Memantine Hydrochloride in Experimental Peripheral Nerve Injury

2019 ◽  
Vol 08 (02) ◽  
pp. 113-118
Author(s):  
Hakan AK ◽  
Iskender Samet Daltaban ◽  
Sevilay Vural
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Group 4 ◽  
Tnf Α ◽  
Group 3 ◽  
The Mean ◽  
Cox 2 ◽  
Group 2 ◽  
Group 1

Abstract Aim In this experimental study, we aimed to investigate possible healing effects of memantine hydrochloride, an N-methyl-d-aspartate (NMDA) antagonist, with clinical, biochemical, and histopathologic methods on acute peripheral nerve injury (PNI). Material and Method Forty-eight adult Wistar albino rats were divided into four groups (n = 12). The groups were arranged as sham-operated group (group 1), acute compression model group (group 2), trauma + low-dose memantine group (group 3), and trauma + high-dose memantine group (group 4). Memantine was administered intraperitoneally for 7 days. Subjects were sacrificed after the measurement of the sciatic nerve function index (SNFI) on the eighth day. Cyclooxygenase 2 (COX-2) and tumor necrosis factor-α (TNF-α) levels were measured in nerve tissues. Histopathologic evaluation was performed by electron microscopy. Results The mean sciatic function index (SFI) scores of groups 1 to 4 were +3.27 (standard deviation [SD] ±4.66),–18.2 (SD = ±11.7),–8.5 (SD = ±7.5), and–2.5 (SD = ±9), respectively. The mean COX-2 values were 0.98 ng/mL (SD = ±0.51), 1.89 ng/mL (SD = ±0.22), 1.39 ng/mL (SD = ±0.36), and 1.35 ng/mL (SD = ±0.59), respectively. TNF-α values were 0.09 pg/mL (SD = ±0.23), 1 pg/mL (SD = ±0.96), 0.46 pg/mL (SD = ±0.55), and 0.48 pg/mL (SD = ±0.78), respectively. Group 1 showed normal histologic findings. Group 2 showed marked edema particularly in large-diameter myelins. Myelin configurations were detected in large myelinated axons in group 3. The number of mast cells in endoneurium was high in group 4. Conclusion The efficacy of memantine in the acute phase of PNI appears to be significant according to the SNFI and biochemical tests. However, histologic findings suggest that high doses of memantine have a negative effect on PNI.

Cyclosporine Dose, Serum Trough Levels, and Allograft Preservation in a Rat Model of Laryngeal Transplantation

2003 ◽  
Vol 112 (6) ◽  
pp. 506-510 ◽  
Author(s):  
Marcus Haug ◽  
Michael Fritz ◽  
Olivia Dan ◽  
Robert R. Lorenz ◽  
Sophie Wimberley ◽  
...  
Keyword(s):  
Rat Model ◽  
High Performance ◽  
Group 4 ◽  
Serum Trough ◽  
Group 3 ◽  
The Mean ◽  
Group 5 ◽  
Group 2 ◽  
Trough Levels ◽  
Group 1

Using a rat model of laryngeal transplantation, we sought to define the relationships between acute laryngeal rejection grade (RG) and cyclosporin A (CSA) concentration and CSA dosage. Five recipient Lewis rat groups (N = 10 per group) were administered intramuscular CSA doses of 1.0 (group 1), 2.5 (group 2), 5.0 (group 3), 7.5 (group 4), and 10 mg/kg per day (group 5) for 14 days. Immediately before sacrifice, 5 mL of whole blood was obtained to assay CSA trough levels by high-performance liquid chromatography. The specimens were graded microscopically by blinded reviewers by day of RG, 0 to 14 days after transplantation, as described in earlier reports. Despite high intragroup variability in CSA levels, significantly different mean CSA concentrations were achieved among all CSA dosage groups: 1,2,3,4, and 5 (.0001 < p < .02). The mean laryngeal RGs did not test significantly different from each other with groups 3, 4, and 5 (RG, 2.3 ± 1.3 versus 1.9 ± 1.1 versus 1.7 ±0.3, respectively, .2 < p < .6). The RG for group 1 was significantly greater than those for groups 2 through 5 (p < .001), and the group 2 RG was greater (p < .02) than those for groups 3, 4, and 5. Polynomial fitting was used to determine the continuous relationship between each individual specimen's CSA concentration and the RG. Significant pathological allograft rejection correlated with CSA concentrations below 250 ng/mL.

PITUITARY LH AND FSH SECRETION AND RESPONSIVENESS IN WOMEN OF OLD AGE

1976 ◽  
Vol 81 (3) ◽  
pp. 673-679 ◽  
Author(s):  
Hugo Scaglia ◽  
Martha Medina ◽  
Ada L. Pinto-Ferreira ◽  
Guadalupe Vazques ◽  
Carlos Gual ◽  
...  
Keyword(s):  
Plasma Levels ◽  
Plasma Concentrations ◽  
Group 4 ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
Post Menopausal ◽  
Episodic Fluctuations ◽  
Lh Rh ◽  
Group 1

ABSTRACT The plasma concentrations and episodic fluctuations of immunoreactive FSH and LH as well as the pituitary sensitivity to LH-RH stimulation were evaluated in post-menopausal women. The subjects were divided into 4 groups according to age. Group 1: 60–70 years old (n=11), group 2: 70–80 years old (n=22), group 3: 80–90 years old (n=31) and group 4: 90–100 years old (n=8). Standards used in gonadotrophin radioimmunoassays included the LER-907 preparation and a pooled post-menopausal serum. Since it was found that circulating gonadotrophins have an immunological pattern different from that shown by the pituitary preparation, the results were expressed in mIU/ml calculated accordingly to the immunological behaviour of pooled post-menopausal sera. The mean (± se) plasma levels of FSH (mIU/ml) were: group 1: 105.9 ± 9.5, group 2: 149.3 ± 10.5, group 3: 124.8 ± 7.1 and group 4: 149.4 ± 25.3. The mean (± se) plasma levels of LH (mIU/ml) were: group 1: 81.9 ± 12.5, group 2: 95.4 ± 9.9, group 3: 84.3 ± 7.7 and group 4: 113.5 ± 19.1. No statistically significant differences were observed among the 4 groups. One patient from each group was randomly selected in order to evaluate their LH and FSH episodic release as well as their pituitary responsiveness to exogenous stimulation. A pulsatile plasma pattern of gonadotrophin and a normal pituitary response to LH-RH injection were observed in the 4 patients studied. The results are interpreted as demonstrating that normal pituitary gonadotrophin function and pituitary reserve and responsiveness to exogenous stimulation are maintained in women of advanced age.

scholarly journals Effects of eliminating tension by means of epineural stitches: a comparative electrophysiological and histomorphometrical study using different suture techniques in an animal model

2011 ◽  
Vol 69 (2b) ◽  
pp. 365-370 ◽  
Author(s):  
J Bustamante ◽  
M Socolovsky ◽  
R S Martins ◽  
J Emmerich ◽  
M G Pennini ◽  
...  
Keyword(s):  
Test Results ◽  
Motor Action ◽  
Nerve Suture ◽  
Group 4 ◽  
Significant Difference ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
Human Nerve ◽  
Group 1

Epineural stitches are a means to avoid tension in a nerve suture. We evaluate this technique, relative to interposed grafts and simple neurorraphy, in a rat model. METHOD: Twenty rats were allocated to four groups. For Group 1, sectioning of the sciatic nerve was performed, a segment 4 mm long discarded, and epineural suture with distal anchoring stitches were placed resulting in slight tension neurorraphy. For Group 2, a simple neurorraphy was performed. For Group 3, a 4 mm long graft was employed and Group 4 served as control. Ninety days after, reoperation, latency of motor action potentials recording and axonal counts were performed. Inter-group comparison was done by means of ANOVA and the non-parametric Kruskal-Wallis test. RESULTS: The mean motor latency for the simple suture (2.27±0.77 ms) was lower than for the other two surgical groups, but lower than among controls (1.69±0.56 ms). Similar values were founding in both group 1 (2.66±0.71 ms) and group 3 (2.64±0.6 ms). When fibers diameters were compared a significant difference was identified between groups 2 and 3 (p=0.048). CONCLUSION: Good results can be obtained when suturing a nerve employ with epineural anchoring stitches. However, more studies are needed before extrapolating results to human nerve sutures.

scholarly journals Ovarian follicular dynamics in buffaloes during different estrus synchronization protocols

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Wael M.B. Noseir ◽  
Iman E. El-Bawab ◽  
Walid R. Hassan ◽  
Mostafa S. Fadel
Keyword(s):  
Hormonal Treatment ◽  
Progesterone Level ◽  
Dominant Follicle ◽  
Group 4 ◽  
Follicle Diameter ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
Mean Concentration ◽  
Estradiol Levels

The current study was carried out on 26 normal cycling buffaloes. Animals were divided into 4 groups according to the hormonal treatment regime. Group 1 included 11 buffaloes without hormonal treatment. Group 2: five buffaloes injected with one dose of 25 mg prostaglandin F2alpha (PGF2α) after ultrasound diagnosis of a mature corpus luteaum in one ovary. Group 3: five buffaloes injected blindly with two doses of 25 mg PGF2α 11-days interval. Group 4: five buffaloes treated with ovsynch protocol. The pattern of follicular growth (FG) and the corpus luteum (CL) regression were monitored by transrectal ultrasound scanning. Estradiol 17β and progesterone profiles were estimated by radioimmunoassay for all groups. Buffaloes in Group 1 showed two (72.7%) or three (27.3%) waves-like patterns of follicular development. The average length of the estrous cycle was 21.75±0.53 and 27.0±0.58 days in 2- and 3- wave cycle respectively. The duration of the CL was 16.63±0.53 and 22.3±0.88 days in 2- and 3- wave cycles. One buffalo in Group 2 did not respond to injection of a single dose of PGF2α, while the other 4 responded. On the day of injection the diameter of the CL was 1.90±0.11 cm and that of dominant follicle was 0.97±0.07 cm. On day 2 after injection the follicle diameter was 1.4±0.09 cm and the preovulatory follicle on days 3-4 was 1.5±0.03 cm. The regressing CL diameter was 1.3±0.07 cm and progesterone level decreased from 6.27±0.82 ng/mL on day 0, to 0.13±0.06 ng/mL on days 3-4 post injection. Estradiol levels were increased from 5.40±1.2 pg/mL on day 0, to 15.09±1.97 pg/mL on day 3-4 post injection. After injection of the first dose of PGF2α, in group 3 the maximum follicle diameter was 1.10±0.04 cm on day 6, then started to regress (0.60±0.04 cm) on days 13-17 after injection. In the 2nd wave, the ovulatory follicle showed marked increase from day 2 (0.34±0.01 cm) till days 13-17 (1.33±0.08 cm). The diameter of CL increased from 1.53±0.03 cm on day 0 of treatment to 1.71±0.04 cm on day 7 of treatment. The second dose of PGF2α resulted in rapid decrease in the diameter of dominant follicle of the first wave from 0.88±0.05 cm on day 11 of treatment to 0.60±0.04 cm on days 13-17 (day of estrus) and rapid increase in the diameter of dominant follicle of the second wave from 0.89±0.08 cm on day 11 to 1.33±0.08 cm on days 13-17. Injection of the second dose of PGF2α on day 11 of treatment caused rapid decline in the progesterone level from 5.62±0.45 ng/mL on day 10, to 1.09±0.34 ng/mL on day 12, and 0.17±0.05 ng/mL on days 13-17. Estradiol levels were 0.76±0.42, 3.97±1.05 and 5.59±1.36 pg/mL on days 10, 12 and days 13-17. In group 4, the diameter of the largest follicle of the four ovulated buffaloes after first gonadotropin-releasing hormone administration was 1.24±0.09 cm, while that of the unovulated buffalo was 0.97 cm. The diameter of the largest follicle of the ovulated buffaloes was 1.03±0.07 and 1.32±0.03 cm on days 7 and 9 of the treatment. The diameter of the CL was 1.6±0.05 and 1.22±0.07 cm on days 7 and 9 of the treatment. The mean concentration of progesterone level was 1.89±0.56 ng/mL on day 6, 0.27±0.12 ng/mL on day 8 and to 0.04±0.01 ng/mL on day 9 of treatment. The mean concentration of estradiol level was 16.07±9.29, 1.11±0.68 and 2.41±0.93 pg/mL on days 6, 8 and 9 of the treatment.

scholarly journals The effects of local nitroglycerin on the surgical delay procedure in prefabricated flaps by vascular implant in rats

2012 ◽  
Vol 27 (12) ◽  
pp. 905-911 ◽  
Author(s):  
Jairo Zacchê de Sá ◽  
José Lamartine de Andrade Aguiar ◽  
Adriana Ferreira Cruz ◽  
Alexandre Ricardo Pereira Schuler ◽  
José Ricardo Alves de Lima ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Delay Procedure ◽  
Surgical Delay ◽  
Group 4 ◽  
Significant Difference ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
Prefabricated Flap ◽  
Group 1

PURPOSE: To evaluate the effect of local nitroglycerin on the viable area of a prefabricated flap for vascular implant in rats, and to investigate the surgical delay procedure. METHODS: A femoral pedicle was implanted under the skin of the abdominal wall in forty Wistar rats. The animals were divided into four groups of ten: group 1 - without surgical delay procedure and local nitroglycerin; group 2 - with surgical delay procedure, but without local nitroglycerin; group 3 - without surgical delay procedure, but with local nitroglycerin; and group 4 - with simultaneous surgical delay procedure and local nitroglycerin. The percentages of the viable areas, in relation to the total flap, were calculated using AutoCAD R 14. RESULTS: The mean percentage value of the viable area was 8.9% in the group 1. 49.4% in the group 2; 8.4% in the group 3 and 1.1% in the group 4. There was significant difference between groups 1 and 2 (p=0.005), 1 and 4 (p=0.024), 2 and 3 (p=0.003), 2 and 4 (p=0.001). These results support the hypothesis that the closure of the arterial venous channels is responsible for the phenomenon of surgical delay procedure. CONCLUSION: Local nitroglycerin did not cause an increase in the prefabricated viable flap area by vascular implantation and decreased the viable flap area that underwent delay procedures.

scholarly journals Effect of Electromagnetic Waves from Mobile Phones on Spermatogenesis in the Era of 4G-LTE

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jong Jin Oh ◽  
Seok-Soo Byun ◽  
Sang Eun Lee ◽  
Gheeyoung Choe ◽  
Sung Kyu Hong
Keyword(s):  
Electromagnetic Field ◽  
Mobile Phones ◽  
Exposure Duration ◽  
Male Rats ◽  
Group 4 ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
4G Lte ◽  
Group 1

Objective. To investigate the effect of long duration exposure to electromagnetic field from mobile phones on spermatogenesis in rats using 4G-LTE. Methods. Twenty Sprague-Dawley male rats were placed into 4 groups according to the intensity and exposure duration: Group 1 (sham procedure), Group 2 (3 cm distance + 6 h exposure daily), Group 3 (10 cm distance + 18 h exposure daily), and Group 4 (3 cm distance + 18 h exposure daily). After 1 month, we compared sperm parameters and histopathological findings of the testis. Results. The mean spermatid count (×106/ml) was 398.6 in Group 1, 365.40 in Group 2, 354.60 in Group 3, and 298.60 in Group 4 (p=0.041). In the second review, the mean count of spermatogonia in Group 4 (43.00) was significantly lower than in Group 1 (57.00) and Group 2 (53.40) (p<0.001 and p=0.010, resp.). The sum of the germ cell counts was decreased in Group 4 compared to Groups 1, 2, and 3 (p=0.032). The mean Leydig cell count was significantly decreased in Group 4 (p<0.001). Conclusions. The longer exposure duration of electromagnetic field decreased the spermatogenesis. Our findings warrant further investigations on the potential effects of EMF from mobile phones on male fertility.

Refractive Error in Patients with Retinopathy of Prematurity after Laser Photocoagulation or Bevacizumab Monotherapy

2015 ◽  
Vol 234 (4) ◽  
pp. 211-217 ◽  
Author(s):  
Hsi-Kung Kuo ◽  
I-Ting Sun ◽  
Mei-Yung Chung ◽  
Yi-Hao Chen
Keyword(s):  
Refractive Error ◽  
Retinopathy Of Prematurity ◽  
Laser Photocoagulation ◽  
Group 4 ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
Type 1 Rop ◽  
Group 1

Purpose: To evaluate the refractive development of premature infants with retinopathy of prematurity (ROP) after treatment with laser photocoagulation or intravitreal injection of bevacizumab (IVB). Methods: The medical records of patients with ROP treated between 2003 and 2012 who underwent yearly follow-ups were retrospectively reviewed. Patients with residual ROP abnormalities were excluded. The cycloplegic refraction at 3 years of age, assessed using an autorefractometer, was recorded. Results: In total, 54 eyes from 54 patients were enrolled. Patients were divided into 4 groups: group 1, including 14 eyes of 14 patients treated with laser therapy; group 2, 15 eyes of 15 patients treated with IVB; group 3, 13 eyes of 13 patients with non-type 1 ROP under conservative follow-up, and group 4, 12 eyes of 12 premature patients without ROP. The mean spherical equivalent at 3 years of age was -1.71 ± 1.27 dpt in group 1, -1.53 ± 2.20 dpt in group 2, 0.63 ± 1.37 dpt in group 3, and 0.41 ± 1.95 dpt in group 4. The mean refractive error differed significantly among the 4 groups (p < 0.001). Patients in groups 1 and 2 were more prone to myopia compared with those in groups 3 and 4. Furthermore, patients with type 1 ROP treated by laser photocoagulation (group 1) and those treated by IVB (group 2) had similar refraction (p = 1). Conclusions: The results of this study suggest that treatment-demanding ROP eyes are susceptible to more severe myopia with age compared with eyes without ROP or those with spontaneously regressed ROP. In addition, the myopic status between laser and IVB treatment did not differ statistically.

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