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Notes: Summary. Birthweight-for-gestational age charts were based on the analysis of 3888 consecutive births in which the gestational age was estimated by measuring the fetal biparietal diameter before the 20th week of gestation. The data showed, in contrast to previous studies, a linear relation between gestational age and birthweight without inflection after term. The regression parameters showed a strongly significant difference between girls and boys. Thus, boys were 1·5% heavier than girls at 190 days gestation and 3·6% heavier at 300 days gestation. The linearity in the birthweight-for-gestational age charts could be due to the more reliable gestational age based on early ultrasound.

Notes: Summary. This paper combines earlier results on the relation between birthweight and gestational age, and the relation between fetal weight and ultrasound measurements of the fetal biparietal diameter (BPD) and mean abdominal diameter (AD) to investigate whether preterm infants (viewed as a group) are smaller than unborn fetuses of the same gestational age. The birthweight distribution for each sex at 223 and 258 days gestation was derived from the birthweight-for-gestational age charts based on 3888 newborn infants. The sex-specific intrauterine weight distribution was estimated from ultrasound measurement of the fetal BPD and AD performed on randomly selected fetuses of gestational age 223 and 258 days. The birthweights were lower than the intrauterine weights, especially early in pregnancy and for female infants. Thus, the 10th birthweight centile for girls at day 223 corresponds to the 4th centile of the‘true’ intrauterine weight, and the‘true’ intrauterine 10th centile corresponds to the 25th centile birthweight at day 223.

Notes: Abstract A relationship between type of luxation injury, stage of root development and development of pulp necrosis after injury has been demonstrated. It was therefore decided to delve more deeply into the relationship between stage of root development and the later development of pulp necrosis after injury in a material of luxated permanent teeth. In this context, the diameter of the apical foramen and the distance from the apical foramen to the pulp horn, as measured on radiographs taken at the time of injury, were used as indicators of root development. In order to justify this approach, the precision of the measuring technique and the accuracy of the radiographic technique were studied. Regarding precision of the measuring technique, it was found that there was a 1% to 4.3% error of the means of all measurements for the various parameters and exposure techniques employed. With respect to accuracy of the radiographic technique, it was found that there was a systematic error in the radio-graphic technique which resulted in a median relative distortion of between 3.5% and 8% image magnification for the various parameters and the exposure techniques employed. These findings indicated that the measuring technique employed in the present investigation was reliable for studying the parameters in question. In a material of 226 extruded, intruded and laterally luxated maxillary permanent incisors, observed for up to 10 years, it was found that the development of pulp necrosis after injury was significantly related to the diameter of the apical foramen. For extruded and laterally luxated teeth, the smaller the diameter, the greater the probability of pulp necrosis. Intruded teeth with incomplete root development (i.e. radiographic diameters ≥1.2 mm) were associated with a much higher probability of pulp survival than teeth with complete root development (i.e. radiographic diameters ≤0.7 mm). The distance from the apical foramen to the pulp horn did not appear to be of importance in predicting pulp survival when diameter of the apical foramen was taken into account. Pulp survival after luxation injuries with displacement thus appears to be dependent upon the size of apical contact between the pulp and the periodontium.