جستجوی مقالات مرتبط با کلیدواژه « Abrasion » در نشریات گروه « پزشکی »

Objective Eye injuries during general anaesthesia (GA) are not common, and are much easier to prevent than to treat, providing theatre staff take care to use correct eye protection. Some operations are at higher risk than others. Our hospital had a recent series of eye injuries which triggered action to investigate the route cause, improve prevention, and provide clinicians with a toolkit to manage those that do occur.SettingThis quality improvement project was done across two hospitals within one trust - Bristol Royal Infirmary and St Michael’s Hospital, both within University Hospitals Bristol and Weston NHS Foundation Trust.Intervention We introduced local training to raise awareness in eye injuries, and an eye guideline (standard operating procedure) which as uploaded onto the trust intranet to clarify eye protection measures for all staff, in addition to guiding management for eye injuries that occur.DiscussionOur guideline divided patients into 2 groups - high risk and low risk for eye injuries. Those with a low risk had their eyes taped. Those meeting criteria for “high risk” included operations on the head and neck, patients with positioning such as prone positioning, lateral positioning, or prolonged/steep head down positioning. These patients are treated with lubricant and dedicated eye tape. We introduced an “Eye Box” which resides in theatre recovery, which can be used by clinicians reviewing patients with a suspected eye injury. This streamlines the process of assessment by consolidating all required equipment and information in one box. The box contains the guideline, equipment to assess the eye (local anaesthetic, fluorescein, ophthalmoscope), as well as chloramphenicol ointment to allow clinicians to initiate treatment immediately.

Parents are aware of the importance of anterior tooth esthetics in their children. Children also pay attention to their appearance more than ever. Today, charcoal has been added to toothpastes. This study aimed to investigate the degree of bleaching and abrasion of charcoal toothpaste on primary teeth.

This in-vitro study was performed on 30 extracted primary teeth. Initially, the samples were polished, cut, and mounted in blocks of putty. The samples were placed in a coffee solution and then the tooth color was measured by a spectrophotometer and the initial surface profile was measured by a profilometer. The samples were brushed back and forth by the brushing machine with 20 gr Bancer, Beverly, and Colgate toothpastes (mixed with 40 ml of distilled water) for 2000 times (equivalent to 3 times a day for 1.5 months). A color determination was performed again and a second surface profile was measured. The data were analyzed by one-way ANOVA, ANCOVA and paired t-test.

The results of this study showed that all three Beverly, Bencer and Colgate whitening toothpastes increased the surface profile and made significant statistical changes in the roughness of dental specimens (P=0.01, P=0.005, P=0.001). The statistical study of the data did not show a significant difference between the groups in terms of abrasion and whitening properties (P=0.78, P= 0.99).

Three whitening toothpastes whiten primary teeth and increase their surface roughness. These three toothpastes are not statistically different in terms of abrasion and whitening properties.

Charcoal toothpastes can whiten teeth through abrasion. The purpose of this study was to determine the level of whitening and abrasiveness of charcoal toothpastes in permanent teeth.

In this in vitro study, 30 premolars were polished, sectioned, mounted, and stored for 5 days in a coffee solution at 37°C. The color and surface profile of the teeth were measured by spectrophotometry and a profilometric device, respectively. The specimens were divided into 3 groups of 10 and were brushed 2000 times(equivalent to 3 times a day for 1.5 months) in a brushing machine using 20 g of each toothpaste (Bencer, Beverly, and Colgate) mixed with 40 ml of distilled water. The color and surface profile were remeasured. Bonferroni test and repeated measures analysis of variance (ANOVA) were used to examine the abrasion. One‑way ANOVA was used to assess the whitening.

The three toothpastes caused changes in the surface profile (P = 0.0001). ΔE was equal to 3.3 (within the acceptable range) in all groups (95% confidence interval). There was no significant difference in abrasion (P > 0.05) and color change (P = 0.884) among toothpastes.

The results of this study showed that all the three used toothpastes have the abrasive and whitening effect on the samples significantly. The differences between the toothpastes were not significant.

The purpose of this study is the evaluation of the amount of surface roughness (Ra) of Zirconia Ceramic following different surface treatments as well as the assessment of its shear bond strength to composite resin. 40 sintered zirconia ceramic block samples were randomly divided in 4 groups of 10 and underwent the following surface treatments:a) Control group without treatmentb) Air abrasion with Al2O3 particles (50um)c) Er:YAG laser with 2W power for 10sd) Nd:YAG laser with 1.5W power for 2minThen the mean surface roughness (Ra) was evaluated by profilometer. In the next step, Alloy primer was used on a section of 9mm2 on the samples following the manufacturer’s instructions. After that Clearfil AP-X composite resin in cylinder shape with an internal diameter and height of 3mm were cured on the sections mentioned. At the end, all samples were tested to assess the shear bond strength by the Universal Testing Machine at a speed of 0.5mm/min until fracture occurred. The mean shear bond strengths were calculated and statistically analyzed by One Way ANOVA. ANOVA analysis showed that roughness (Ra) was significantly different between the groups (P≤0.05). Ra was higher in the Nd:YAG group compared to the other groups (P≤0.05). The lower Ra was related to the control group. Air abrasion group showed highest amounts of shear bond strength and Nd:YAG laser group demonstrated lower amounts of shear bond strength (P≤0.05). Various surface treatments are differently effective on bond strength. Air abrasion is the most effective method to condition zirconia ceramic surfaces.

Low resistance of composite resins to abrasion is a primary concern in the application of these materials for posterior restorations which are prone to high occlusal loads. This study compared the wear resistance of three types of composites. In this laboratory experiment, five specimens of each of the three types of composites (z250, Heliomolar, Opallis) were prepared separately in brass molds. Composites were placed in 1-mm layers and were cured for 40 seconds. Using an abrasive device, Pedeb 1, with a chrome-cobalt abrasor, the specimens were abraded under a 20-MPa force, after 5000, 20000, 40000, 80000, 120000 abrasive rotations. Before and after all abrasion cycles, the specimens were weighed with an electronic balance with a precision of 10-4 g. The collected data were analyzed using paired samples statistics t-test and ANOVA analysis. All the specimens showed a reduction pattern from the initial weights to weights after 120000 abrasive rotations. With more abrasive rotations, greater weight reduction occurs and this is of statistical significance. ANOVA analysis showed no significant difference between the three types of composites; yet, the z250 and Heliomolar groups were associated with the least and the greatest amount of wear, respectively. In all specimens, significant weight reduction occurred after abrasion but there were no significant differences between the 3 types of composites.