Blood contamination of abutment screw holes was shown to significantly decrease RTVs. Blood contamination may result in greater loosening of implant screws in clinical practice.

When selecting appropriate patients (adequate primary stability, patient compliance with the surgeon's recommendations), immediate implant loading may be an alternative method to late loading protocol for replacement of a missing tooth in anterior maxilla.

Background/purpose: The aim of this study was to determine the accuracy of casts made from irreversible hydrocolloid impressions with immediate and delayed pouring. Materials and methods: A master model was mounted on a modified articulator designed to standardize impression procedures. A total of 250 impressions were taken and grouped into 25 groups (n Z 10) according to irreversible hydrocolloid material (CA37, Tropicalgin, ColorChange, Hydrogum 5, and Hydrocolor 5) and storage time (0 hours, 1 hour, 24 hours, 72 hours, and 120 hours). Impressions were stored at 23 AE 1 C and 100% relative humidity and poured with gypsum at the predetermined storage time. Casts were scanned with a threedimensional (3D) model scanner. The digital models were measured and subtracted from the measurements obtained from the master model. The absolute values of dimensional differences were statistically analyzed using two-way analysis of variance (ANOVA) and post hoc Fisher LSD test (P < 0.05). Results: Different irreversible hydrocolloids and pouring times showed significant differences (P < 0.001). In all irreversible hydrocolloids, no statistically significant differences were found with impressions poured after 0 hours, 1 hour, and 24 hours of storage (P > 0.05). However, after 72 hours and 120 hours of storage, Tropicalgin and CA37 irreversible hydrocolloid impressions were found to be significantly different (P < 0.05). Moreover, ColorChange, Hydrogum 5, and Hydrocolor 5 irreversible hydrocolloid impressions were not statistically different up to 120 hours (P > 0.05). (M. Dinçel). + MODELPlease cite this article in press as: Gümüs ‚ HÖ, et al., The effect of pouring time on the dimensional stability of casts made from conventional and extended-pour irreversible hydrocolloids by 3D modelling, Journal of Dental Sciences (2014), http://dx.

PURPOSEThis study was to evaluate the effect of grinding of the inner metal surface during the porcelain try-in stage on metal-porcelain bonding considering the maximum temperature and the vibration of samples.MATERIALS AND METHODSNinety-one square prism-shaped (1 × 1 × 1.5 mm) nickel-chrome cast frameworks 0.3 mm thick were prepared. Porcelain was applied on two opposite outer axial surfaces of the frameworks. The grinding was performed from the opposite axial sides of the inner metal surfaces with a low-speed handpiece with two types of burs (diamond, tungsten-carbide) under three grinding forces (3.5 N, 7 N, 14 N) and at two durations (5 seconds, 10 seconds). The shear bond strength (SBS) test was performed with universal testing machine. Statistical analyzes were performed at 5% significance level.RESULTSThe samples subjected to grinding under 3.5 N showed higher SBS values than those exposed to grinding under 7 N and 14 N (P<.05). SBS values of none of the groups differed from those of the control group (P>.05). The types of bur (P=.965) and the duration (P=.679) did not affect the SBS values. On the other hand, type of bur, force applied, and duration of the grinding affected the maximum temperatures of the samples, whereas the maximum vibration was affected only by the type of bur (P<.05).CONCLUSIONGrinding the inner metal surface did not affect the metal-porcelain bond strength. Although the grinding affected the maximum temperature and the vibration values of the samples, these did not influence the bonding strength.