scholarly journals Long-term effects of different cleaning methods on copolyester retainer properties

2018 ◽  
Vol 89 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Emily Wible ◽  
Manika Agarwal ◽  
Sibel Altun ◽  
Tyler Ramir ◽  
Grace Viana ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Artificial Saliva ◽  
Flexural Modulus ◽  
Qualitative Difference ◽  
Light Transmittance ◽  
Qualitative Assessment ◽  
Long Term Effects ◽  
Chemical Cleaning ◽  
Cleaning Methods

ABSTRACT Objective: To evaluate light transmittance, surface roughness, and flexural modulus of copolyester retainer material after long-term exposure to different cleaning methods. Materials and Methods: Standardized copolyester retainer specimens (ACE) were subjected to seven chemical cleaning solutions for 6 months: Invisalign cleaning crystals, Retainer Brite, Polident, Listerine mouthwash, 2.5% acetic acid, 0.6% NaClO, and 3% H2O2. Seventy specimens (n = 10 per method, 50.8 mm × 12.7 mm × 1.0 mm) were exposed to the different solutions twice a week for 2 minutes or according to manufacturer's instructions and stored in artificial saliva at 37°C. Another group of specimens (n = 10) was brushed with a standardized toothbrushing machine for 2 minutes twice a week. At baseline and 6 months, light transmittance, surface roughness and flexural modulus of the specimens were quantified using spectrophotometry, profilometry, and three-point bend testing, respectively. Qualitative assessment was performed using scanning electron microscopy (SEM). Statistical analyses were accomplished at a significance level of .05. Results: The results indicated that light transmittance through the specimens decreased significantly from baseline for all cleaning methods at 6 months. Flexural modulus of the specimens decreased significantly for all cleaning methods except Invisalign crystals and Retainer Brite (P > .05). The Listerine group demonstrated the worst light transmittance change while H2O2 demonstrated the greatest change in flexural modulus of the specimens compared with other cleaning methods; however, no qualitative difference was observed using SEM analysis. Conclusions: The results suggest that different cleaning methods affect long-term physical properties of the ACE retainer material. At the present time, none of these cleaning methods is ideal for copolyester retainer material.

scholarly journals Long-term effects of various cleaning methods on polypropylene/ethylene copolymer retainer material

2019 ◽  
Vol 89 (3) ◽  
pp. 432-437 ◽  
Author(s):  
Emily Wible ◽  
Manika Agarwal ◽  
Sibel Altun ◽  
Tyler Ramir ◽  
Grace Viana ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Artificial Saliva ◽  
Flexural Modulus ◽  
Light Transmittance ◽  
Long Term Effects ◽  
Chemical Cleaning ◽  
Sem Images ◽  
Ethylene Copolymer ◽  
Cleaning Methods

ABSTRACT Objectives: To evaluate long-term light transmittance, surface roughness, and flexural modulus of polypropylene/ethylene copolymer retainer material after exposure to different cleaning methods. Materials and Methods: Standardized polypropylene/ethylene copolymer retainer specimens (n = 70, 50.8 mm × 12.7 mm × 1.0 mm) were subjected to seven chemical cleaning solutions: Invisalign cleaning crystals, Retainer Brite, Polident, Listerine mouthwash, 2.5% acetic acid, 0.6% NaClO, and 3% H2O2 for 6 months. The specimens were exposed to the different solutions twice a week for 15 minutes or according to manufacturer's instructions, then stored in artificial saliva at 37°C. Another group of specimens (n = 10) were brushed with a standardized toothbrushing machine for 2 minutes twice a week. At baseline and 6 months, light transmittance, surface roughness, and flexural modulus of the specimens were quantified using spectrophotometry, profilometry and three-point bend testing, respectively. Qualitative analysis was performed using a scanning electron microscope (SEM). Statistical analyses were performed at a significance level of .05. Results: The results showed that light transmittance decreased significantly from baseline for all cleaning methods at 6 months. For an individual method, no significant differences were observed between specimens at baseline and 6 months in surface roughness and flexural modulus. No discernible differences in surface features were observed on SEM images. Conclusions: The results indicate that different cleaning methods affect the long-term light transmittance of the studied polypropylene/ethylene copolymer retainer material. However, for an individual cleaning method, no significant differences were shown for surface roughness or flexural modulus values at 6-months compared to baseline.

scholarly journals Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material

2018 ◽  
Vol 88 (3) ◽  
pp. 355-362 ◽  
Author(s):  
Manika Agarwal ◽  
Emily Wible ◽  
Tyler Ramir ◽  
Sibel Altun ◽  
Grace Viana ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Flexural Modulus ◽  
The Other ◽  
Light Transmittance ◽  
Qualitative Assessment ◽  
Long Term Effects ◽  
Significance Level ◽  
Cleaning Methods ◽  
Scanning Electron

ABSTRACT Objectives: To evaluate the long-term effects of seven different cleaning methods on light transmittance, surface roughness, and flexural modulus of a polyurethane retainer material. Materials and Methods: Polyurethane retainer specimens (Vivera®, Align Technology Inc) (70 specimens, n = 10 per method, 50.8 mm × 12.7 mm × 1.0 mm) were exposed to seven cleaning methods twice a week for 6 months. Before treatment and after 6 months, light transmittance, surface roughness, and flexural modulus of the specimens were quantified. Qualitative assessment of randomly selected specimens from each solution was performed at baseline and after 6 months using a scanning electron microscope. Statistical analyses were performed at the .05 significance level. Results: Of the three test variables, light transmittance through the specimens was the only one that changed significantly from baseline to 6 months for all cleaning solutions, with all of them causing a decrease. However, except for 0.6% sodium hypochlorite showing a change in surface roughness values and 2.5% vinegar and toothbrushing showing an increase in flexural modulus, none of the other four cleaning methods resulted in significant changes in surface roughness or flexural modulus values for the polyurethane specimens between baseline and after 6 months. Conclusions: Of the seven cleaning methods, Invisalign® cleaning crystals, Polident®, and Listerine® showed the least amount of change in light transmittance values for the polyurethane specimens over 6 months, and they had no effect on surface roughness and flexural modulus values.

Long-term effects of chemical cleaning in the performance of ultrafiltration ceramic membranes

Desalination ◽  
2006 ◽  
Vol 200 (1-3) ◽  
pp. 316-318 ◽  
Author(s):  
José E. Zapata-Montoya ◽  
Emilia M. Guadix ◽  
Antonio Guadix
Keyword(s):  
Ceramic Membranes ◽  
Long Term Effects ◽  
Chemical Cleaning

Understanding membrane fouling in ultrafiltration of WWTP-effluent

2000 ◽  
Vol 41 (10-11) ◽  
pp. 345-353 ◽  
Author(s):  
J.H. Roorda ◽  
J.H. van der Graaf
Keyword(s):  
Membrane Fouling ◽  
Waste Water Treatment ◽  
Rapid Decrease ◽  
Short Term ◽  
Chemical Cleaning ◽  
Water Treatment Plants ◽  
Wwtp Effluent ◽  
Pre Treatment ◽  
Cleaning Methods

The application of ultrafiltration to effluent of waste water treatment plants (WWTP-effluent) is getting increasing attention. However, many experiments show a rapid decrease in flux urging frequent and intensive cleaning. In order to understand the mechanisms of the occurring fouling process, various filtration and cleaning experiments were performed, giving information about the filterability of the feedwater (F) and the reversibility of the occurring fouling layer (R). Short-term fluxes are mainly determined by the filterability, while both the filterability and the reversibility greatly affect long-term fluxes. The objective of this research is to measure the filterability of WWTP-effluent and the reversibility of the occurring fouling layer in ultrafiltration of wwtp-effluent with and without pre-treatment. The results of the filtration experiments show a rapid decrease of flux resulting in a low value for the filterability, which also decreases during progressing filtration. The filterability is mainly related to the volume of treated water. Pre-treatment of the WWTP-effluent by in-line coagulation or by deep-bed filtration has little influence on the filterability. However, results on the reversibility show an improvement of the reversibility by pre-treatment. Both filterability of the WWTP-effluent and reversibility of the fouling layer are found to be independent of the applied flux. As to the applied cleaning methods, the back flush is far more effective than the forward flush even if combined with air. In all experiments the remaining fouling layer still has to be removed by an intensive chemical cleaning. This research indicates the very importance of reducing the formation of an irreversible, non-removable fouling layer.

Effects of corrosion and cleaning method on taper dimensions: an in vitro investigation

2019 ◽  
Vol 30 (1) ◽  
pp. 87-92
Author(s):  
Ahmad Faizan ◽  
Jason Longaray ◽  
Jim E Nevelos ◽  
Geoffrey H Westrich
Keyword(s):  
Surface Roughness ◽  
Statistical Significance ◽  
Cone Angle ◽  
Long Term Effects ◽  
Cleaning Method ◽  
In Vitro Investigation ◽  
Orthopaedic Literature ◽  
Femoral Heads ◽  
Measuring Machine ◽  
Cleaning Methods

Purpose: Taper corrosion related revisions have recently been reported in the orthopaedic literature. Cleaning procedure of the trunnions during hip revision is not standardised. The purpose of this bench top investigation was to understand the alterations in the trunnion dimensions and surface roughness characteristics as a result of corrosion product build-up. Methods: 8 titanium alloy trunnions and CoCr femoral heads assemblies were cyclically tested in a mechanical simulator. Following disassembly of the tested constructs, the trunnions were cleaned using 2 methods. The trunnion dimensions were measured using coordinate measuring machine, and surface roughness was measured using white light interferometry. The trunnions were reassembled with ceramic femoral heads and titanium sleeves following cleaning. Head/sleeve pull-off testing was conducted to understand the effects of cleaning methods on the pull-off strength. Results: Grade 4 corrosion was observed on all trunnions after mechanical testing. The aggressive cleaning methods had a larger impact on the surface roughness when compared to the light cleaning method. The aggressive cleaning method also decreased the taper cone angle. The pull-off strength was not affected by the cleaning method and the pull-off values were approximately 50% of the assembly loads. Conclusions: The study suggests that trunnion cleaning method may alter the surface roughness and taper cone angle of the existing trunnion. However, the effects of these changes on the pull-off strength did not reach statistical significance. Complex corrosion testing under cyclic loading conditions are warranted to understand the long-term effects of these changes.

Resin-based Composite Light-cured Properties Assessed by Laboratory Standards and Simulated Clinical Conditions

2013 ◽  
Vol 38 (2) ◽  
pp. 159-167 ◽  
Author(s):  
N Ilie ◽  
H Bauer ◽  
M Draenert ◽  
R Hickel
Keyword(s):  
Irradiation Time ◽  
Light Emitting Diode ◽  
Artificial Saliva ◽  
Flexural Modulus ◽  
Storage Conditions ◽  
Material Behavior ◽  
Indentation Modulus ◽  
Light Emitting ◽  
Clinical Conditions

SUMMARY The following parameters were varied: 1) irradiation technique: top and bottom polymerization according to the ISO standard, and polymerization from only the top, simulating clinical situations; 2) polymerization time: 5, 10, 20, and 40 seconds; 3) storage conditions: 24 hours in distilled water, thermocycling followed by storage for four weeks in artificial saliva or alcohol. Flexural strength (FS), flexural modulus (Eflexural), indentation modulus (E), Vickers hardness (HV), and degree of conversion (DC) were measured. The laboratory results were similar to those measured by mimicking clinical conditions only at high polymerization times and mild storage conditions (20 seconds and 40 seconds and storage for 24 hours in water, and 40 seconds with aging and storing in saliva). Significantly higher DC values were measured on the top than on the bottom of a 2-mm layer for all polymerization times. Overall, 5-second and 10-second irradiation times induced significantly lower DC values compared to the currently recommended polymerization times of 20 and 40 seconds at both the top and bottom of the samples. The initial DC differences as a function of irradiation time are leveled at 24 hours of storage but seem to do well in predicting long-term material behavior. A minimum irradiation time of 20 seconds is necessary clinically to achieve the best mechanical properties with modern high-intensity light emitting diode (LED) units.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

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