Hardening of Dental Gold-Copper Alloys
X-ray diffraction studies of several proprietary dental gold alloys demonstrated that hardening probably is a dual mechanism of precipitation and order-hardening. Lattice parameter measurements showed that the ordered structure was AuCu. In addition, it was shown that maximum hardness occurs at about 75% full order.
Effect of heat treatments on machinability of gold alloy with age-hardenability at intraoral temperature.
OBJECTIVE
This study investigated the effect of heat treatment on the machinability of heat-treated cast gold alloy with age-hardenability at intraoral temperature using a handpiece engine with SiC wheels and an air-turbine handpiece with carbide burs and diamond points.


METHODS
Cast gold alloy specimens underwent various heat treatments [As-cast (AC); Solution treatment (ST); High-temperature aging (HA), Intraoral aging (IA)] before machinability testing. The machinability test was conducted at a constant machining force of 0.784N. The three circumferential speeds used for the handpiece engine were 500, 1,000 and 1,500 m/min. The machinability index (M-index) was determined as the amount of metal removed by machining (volume loss, mm(3)). The results were analyzed by ANOVA and Scheffé's test.


RESULTS
When an air-turbine handpiece was used, there was no difference in the M-index of the gold alloy among the heat treatments. The air-turbine carbide burs showed significantly (p<0.05) higher M-indexes than the diamond points after any heat treatments. With the SiC wheels, increasing the circumferential speed increased the M-index values for each heat treatment. The specimens heat-treated with AC, HA and IA had similar M-indexes at the lower speeds (500 and 1,000 m/min). The ST specimens exhibited the lowest M-index at the lower speeds. However, at the highest speed (1,500 m/min), there were no significant differences in the M-indexes among the heat treatments except for HA, which showed the highest M-index.


CONCLUSION
There was no effect of heat treatment on the machinability of the gold alloy using the air-turbine handpiece. The heat treatments had a small effect on the M-index of the gold alloy machined with a SiC wheel for a handpiece engine.
Relationship between level of internet addiction and time management skills among nursing students.
PURPOSE
This study investigated nursing students' levels of internet addiction (IA) and time management (TM) skills.


DESIGN AND METHODS
This cross-sectional descriptive study was conducted with 400 nursing students of a university in Turkey. The data were collected using the Personal Information Form, IA Scale, and TM Inventory.


FINDINGS
The IA scale and TM inventory mean scores were 40.83 ± 14.81 and 81.34 ± 11.91, respectively. A significantly negative relationship between students' level of IA and TM skills was found (p <0.05).


PRACTICE IMPLICATIONS
The concept of effective time management should be used in interventions for promoting students' conscious internet use.