[Comparison of late second-trimester non-stress test characteristics between small for gestational age and appropriate for gestational age fetuses]

Background: The purpose of this study was to compare electronic fetal heart rate monitoring [EFM] characteristics between Appropriate for Gestational Age [AGA] and Small for Gestational Age [SGA] fetuses and to determine whether SGA fetuses have specific abnormalities

Materials and Methods: Among children born from Apr 2002 to Mar 2003 in Arash hospital, we identified 300 singleton infants born after 36 weeks' gestation of uncomplicated pregnancies in whom second-trimester [24-27 weeks' gestation] EFM records were obtained. Individual components of fetal heart rate [FHR] pattern baseline rate, baseline FHR variability, presence of acceleration and periodic and episodic deceleration, and birth characteristics were compared between AGA and SGA infants or between pregnancies with or without second-trimester decelerations. Statistical analysis was performed using Student t, Chi square and Fisher exact test

Results: Among 300 infants, 261 [87%] were AGA and 39 [13%] were SGA 65 had and 235 did not have second-trimester decelerations. Baseline FHR variability, second- trimester decelerations and intrapartum FHR decelerations were significantly higher in SGA fetuses than in AGA fetuses [P<0.05]. Birth weight and gestational age were significantly lower in SGA fetuses than in AGA fetuses [P<0.05]. There were no significant differences in baseline rate and acceleration, maternal age and parity, Apgar score in 1 minute, meconium staining, mode of delivery, NICU admission, between SGA and AGA infants. Small for Gestational Age infants were more frequent in pregnancies with second-trimester decelerations compared with those without second-trimester deceleration [P<0.05]. Baseline FHR variability in pregnancies with second-trimester decelerations was significantly higher than in pregnancies without second-trimester deceleration [P<0.05]

Conclusion: Periodic or episodic decelerations and increased FHR variability during late second-trimester EFM were associated with an increased risk of SGA infant

[ evaluation on the consistency and working time of an Iranian impression material [Duralite] and comparing it with a foreign product [luralite]]

Background and aim: Zinc oxide eugenol [ZOE] impression material, due to its favorable characteristics, has numerous uses in removable denture impression making and jaw relation recording. In Iran, this material is commercially produced as Duralite. The purpose of this study was to investigate consistency and working time of Iranian ZOE [Duralite] and compare it with foreign ZOE ]Luralite] based on British standard 4284: 1981

Materials and Methods: in this invitro experimental study, forty samples were studied. An apparatus for the determination of material consistency and a penetrometer for working time measurement were used. For consistency measurement, 0.5cc of each impression paste was put between two glass plates and under one 1500gr. load. After 15 seconds, the diameter of resulting disk was measured with a digital caliper. For working time measurement, each paste was put in a metal ring [diameter: 30mm, height: 3mm] and then in 30-second intervals the penetration of penetrometer needle was measured. Data were analyzed by t-student test

Results: mean consistency of Duralite impression material was measured 43.42+/-2rnm and that of luralite was 45.22+/-lmm. Mean working time for Duralite impression material was measured 2':50"+/-01:19" and for Luralite was 81:30"+/-0:25". The results of this study revealed that the consistency and working time of Duralite and Luralite impression materials are within the range of British standard

Conclusion: no statistically significant difference was found in mean consistency of Duralite and Luralite impression materials [P=0.08], but there is a significant difference between their mean working times [P <0.001]