Judgment of the Quality of Restorative Care as Predictors of Restoration Retreatment: Findings from the National Dental PBRN.

The primary aim of this study was to test the hypothesis that a patient's subjective assessments of the dentist's technical competence, quality of care, and anticipated restoration longevity during a restorative visit are predictive of restoration outcome. This prospective cohort study involved 3,326 patients who received treatment for a defective restoration in a permanent tooth, participated in a baseline patient satisfaction survey, and returned for follow-up. Of the 4,400 restorations that were examined by 150 dentists, 266 (6%) received additional treatment after baseline. Reporting satisfaction with the technical skill of the dentist or quality of the dental work at baseline was not associated with retreatment after baseline. However, patients' views at baseline that the fee was reasonable (odds ratio [OR], 1.6) was associated with retreatment after baseline, whereas satisfaction at baseline with how long the filling would last (OR, 0.6) was associated with less retreatment. These findings suggest that retreatment occurs more often for patients who at baseline are satisfied with the cost or who at baseline have less confidence in the restoration. The authors found no associations between restoration retreatment and the patients' baseline evaluations of the technical skills of their dentists or perceptions of quality care. KNOWLEDGE TRANSFER STATEMENT: Dental patients' ratings of their dentist's skills were not related to a restoration needing retreatment. Patients focus on other aspects of the dental visit when making this judgment.

Coupled-oscillator theory of dispersion and Casimir-Polder interactions.

We address the question of the applicability of the argument theorem (of complex variable theory) to the calculation of two distinct energies: (i) the first-order dispersion interaction energy of two separated oscillators, when one of the oscillators is excited initially and (ii) the Casimir-Polder interaction of a ground-state quantum oscillator near a perfectly conducting plane. We show that the argument theorem can be used to obtain the generally accepted equation for the first-order dispersion interaction energy, which is oscillatory and varies as the inverse power of the separation r of the oscillators for separations much greater than an optical wavelength. However, for such separations, the interaction energy cannot be transformed into an integral over the positive imaginary axis. If the argument theorem is used incorrectly to relate the interaction energy to an integral over the positive imaginary axis, the interaction energy is non-oscillatory and varies as r(-4), a result found by several authors. Rather remarkably, this incorrect expression for the dispersion energy actually corresponds to the nonperturbative Casimir-Polder energy for a ground-state quantum oscillator near a perfectly conducting wall, as we show using the so-called "remarkable formula" for the free energy of an oscillator coupled to a heat bath [G. W. Ford, J. T. Lewis, and R. F. O'Connell, Phys. Rev. Lett. 55, 2273 (1985)]. A derivation of that formula from basic results of statistical mechanics and the independent oscillator model of a heat bath is presented.

Lorentz transformation of blackbody radiation.

We present a simple calculation of the Lorentz transformation of the spectral distribution of blackbody radiation at temperature T. Here we emphasize that T is the temperature in the blackbody rest frame and does not change. We thus avoid the confused and confusing question of how temperature transforms. We show by explicit calculation that at zero temperature the spectral distribution is invariant. At finite temperature we find the well-known result familiar in discussions of the 2.7 K cosmic radiation.

Developmental coordination disorder at 8 years of age in a regional cohort of extremely-low-birthweight or very preterm infants.

The aims of this study were to determine the motor outcome of extremely-low-birthweight (ELBW; <1000g) or very preterm (<28wks) children compared with normal birthweight (NBW) children, to establish the perinatal associations of developmental coordination disorder (DCD) and its cognitive and behavioural consequences. Participants were consecutive surviving ELBW or very preterm children and randomly selected NBW(>2499g) children born in the state of Victoria, Australia, in 1991 or 1992. Main outcomes were: (1) results of the Movement Assessment Battery for Children (MABC) at 8 years of age; (2) cognitive function; (3) academic progress; and (4) behaviour. Of 298 consecutive ELBW/very preterm survivors, 255 (85.6%; 117 males, 138 females) had the MABC at a mean age of 8 years 8 months. More ELBW/very preterm children (9.5%) had DCD than the NBW group (2%, p=0.001). Only male sex increased the likelihood of DCD in ELBW/very preterm children (p=0.017). ELBW/very preterm children with DCD had worse cognitive function and academic test scores (up to 1SD below those without DCD); they also had more adaptive behaviour and externalizing problems, but not internalizing problems. DCD is more common in ELBW/very preterm children, has few perinatal correlates, and is associated with poor cognitive and academic performance as well as increased behaviour problems.

A quantum violation of the second law?

An apparent violation of the second law of thermodynamics occurs when an atom coupled to a zero-temperature bath, being necessarily in an excited state, is used to extract work from the bath. Here the fallacy is that it takes work to couple the atom to the bath and this work must exceed that obtained from the atom. For the example of an oscillator coupled to a bath described by the single relaxation time model, the mean oscillator energy and the minimum work required to couple the oscillator to the bath are both calculated explicitly and in closed form. It is shown that the minimum work always exceeds the mean oscillator energy, so there is no violation of the second law.

Extremely low birth weight and body size in early adulthood.

AIMS: To determine the body size of extremely low birth weight (ELBW, birth weight 500-999 g) subjects in early adulthood. METHODS: Cohort study examining the height and weight of 42 ELBW survivors free of cerebral palsy between birth and 20 years of age. Weight and height measurements were converted to Z (SD) scores. RESULTS: At birth the subjects had weight Z scores substantially below zero (mean birth weight Z score -0.90, 95% CI -1.25 to -0.54), and had been lighter than average at ages 2, 5, and 8 years. However, by 14, and again at 20 years of age their weight Z scores were not significantly different from zero. At ages 2, 5, 8, 14, and 20 years of age their height Z scores were significantly below zero. Their height at 20 years of age was, however, consistent with their parents' height. As a group they were relatively heavy for their height and their mean body mass index (BMI) Z score was almost significantly different from zero (mean difference 0.42, 95% CI -0.02 to 0.84). Their mean BMI (kg/m2) was 24.0 (SD 5.2); 14 had a BMI >25, and four had a BMI >30. CONCLUSIONS: Despite their early small size, by early adulthood the ELBW subjects had attained an average weight, and their height was consistent with their parents' height. They were, however, relatively heavy for their height.

Growth promotion in chickens by interleukin-2.

Chicken interleukin-2 (cIL-2), which was prepared by sensitizing chicken lymphocytes with concanavalin A, was administered to fertile broiler eggs on Day 18 of embryonation (0.1 mg in 200 mL distilled water). Controls (CON) received distilled water. Hatched chicks were reared to 6 wk. Body weight (BW), as well as abdominal fat pad, liver, bursa of Fabricius, a thymic lobe, spleen, and gonads were excised and expressed relative to BW at 2, 4, and 6 wk of age. Additionally, hematocrit (HCT), hemoglobin (HGB), and plasma protein (PP) levels were determined at the three time intervals. Finally, chicks were sensitized against human gamma globulin (HGG) and challenged at 6 wk by intradermal injections into the wattles. Delayed type hypersensitivity (DTH) to HGG was used as a direct measure of cell-mediated immunity. In ovo cIL-2 increased BW consistently, relative fat pad weights at 2 wk, relative bursa and liver weights at 2 and 6 wk, HBG and relative thymic weight at 2 and 4 wk, and PP at 2 wk. Delayed type hypersensitivity to HGG was not affected by cIL-2. Potential metabolic and immunologic mechanisms to explain in ovo cIL-2 effects are discussed.

Auditory function at 14 years of age of very-low-birthweight.

The aim of the study was to determine audiological function at 14 years of age of very-low-birthweight (VLBW < or = 1500 g) children compared with a cohort of normal birthweight (NBW > 2499 g) children. Participants were consecutive surviving preterm children of birthweight < 1000 g born between 1977 and 1982 (n=86) and of birthweight 1000 to 1500 g born between 1980 and 1982 (n=124) and randomly selected NBW children born between 1981 and 1982 (n=60). Audiometric tests included pure tone audiometry, tympanometry, stapedius muscle reflexes, and measures of central auditory processing. Psychometric tests included measures of IQ, academic achievement, and behaviour. There were no significant differences in rates of hearing impairment, abnormal tympanograms, figure-ground problems, or digit recall between VLBW children and NBW control children. VLBW children had higher rates of some central auditory processing problems, which in turn were associated with poorer intellectual, academic, and behavioural progress.

Birth weight <1501 g and respiratory health at age 14.

AIMS: To determine the respiratory health in adolescence of children of birth weight <1501 g, and to compare the results with normal birthweight controls. METHODS: Prospective cohort study of children born in the Royal Women's Hospital, Melbourne. Two cohorts of preterm children (86 consecutive survivors 500-999 g birth weight, and 124 consecutive survivors 1000-1500 g birth weight) and a control group of 60 randomly selected children >2499 g birth weight were studied. Children were assessed at 14 years of age. A paediatrician determined the clinical respiratory status. Lung function was measured according to standard guidelines. RESULTS: Of 180 preterm children seen at age 14, 42 (23%) had bronchopulmonary dysplasia (BPD) in the newborn period. Readmission to hospital for respiratory ill health was infrequent in all groups and the rates of asthma were similar (15% in the 500-999 g birth weight group, 21% in the 1000-1500 g birth weight group, 21% in controls; 19% BPD, 18% no BPD). Overall, lung function was mostly within the normal range for all cohorts; few children had lung function abnormalities in clinically significant ranges. However, the preterm children had significantly lower values for variables reflecting flow. Lung function in children of 500-999 g birth weight was similar to children of 1000-1500 g birth weight. Preterm children with BPD had significantly lower values for variables reflecting flow than children without BPD. CONCLUSIONS: The respiratory health of children of birth weight <1501 g at 14 years of age is comparable to that of term controls.

Very low birth weight and growth into adolescence.

OBJECTIVE: To compare the growth and pubertal development of very low-birth-weight (VLBW) children (birth weight <1500 g) and normal-birth-weight (NBW) children (birth weight >2499 g) to adolescence to determine if, and at what age, VLBW children "catch up." DESIGN: Inception cohort study to age 14 years. SETTING: Royal Women's Hospital, Melbourne, Australia. PATIENTS: Eighty-six consecutive survivors with a birth weight less than 1000 g, 120 consecutive survivors with a birth weight of 1000 to 1499 g, and 60 randomly selected NBW controls. Children with cerebral palsy at age 14 years were excluded. MAIN OUTCOME MEASURES: Weight, height, and head circumference measurements at birth and ages 2, 5, 8, and 14 years converted to z (SD) scores. RESULTS: At age 14 years, pubertal development was similar in NBW and VLBW children. At ages 2, 5, 8, and 14 years, VLBW children were significantly shorter and lighter and had smaller head circumferences than NBW children. The differences in height and weight between VLBW and NBW children were less apparent as SD scores improved in VLBW children over time. Within the VLBW group, compared with children with a birth weight of 1000 to 1499 g, those with a birth weight less than 1000 g had significantly lower weight z scores earlier in childhood but not at age 14 years, significantly lower height z scores only at age 2 years, and significantly lower head circumference z scores throughout childhood. CONCLUSION: This group of VLBW children experienced late catch-up growth to age 14 years but remain smaller than their NBW peers. Arch Pediatr Adolesc Med. 2000;154:778-784

Antenatal corticosteroids and outcome at 14 years of age in children with birth weight less than 1501 grams.

OBJECTIVE: To determine whether exposure to antenatal corticosteroid therapy was associated with adverse effects on growth, sensorineural outcome, or lung function of children of birth weight <1501 g at 14 years of age. DESIGN: Cohort study. SETTING: The Royal Women's Hospital, Melbourne, Australia. SUBJECTS: One hundred fifty-four consecutive survivors born from October 1, 1980 to March 31, 1982. INTERVENTIONS: The mothers of 78 survivors (51%) had been given corticosteroids antenatally to accelerate fetal lung maturation. Treatment with antenatal corticosteroids was nonrandom. No mother received >1 course of corticosteroids. OUTCOME MEASURES: The children were assessed at 14 years of age, corrected for prematurity. All assessors were unaware of the exposure of the child to antenatal corticosteroids. The assessments included measurements of growth and neurological, cognitive, and lung function. Growth measurements were converted into z scores (standard deviation) for the appropriate age and gender. RESULTS: Of the 154 survivors, 130 (84%) were assessed at 14 years of age. Overall, the children exposed to antenatal corticosteroids were significantly taller (height z score; mean difference:.39; 95% confidence interval:.001-. 79) and had better cognitive functioning (Wechsler Intelligence Scale for Children-Third Edition Full Scale; IQ mean difference: 6. 2; 95% confidence interval:.8-11.6) than those not exposed to corticosteroids. There were no other differences in sensorineural outcomes between the groups. Lung function was not significantly different between the groups. No conclusions were altered by adjustment for confounding variables. CONCLUSIONS: Exposure to 1 course of antenatal corticosteroid therapy was associated with some clinically and statistically improved outcomes at 14 years of age in children of birth weight <1501 g, with no obvious adverse effects on growth or on sensorineural, cognitive, or lung function. corticosteroids, growth, cognitive, IQ, lung function, adolescence.

Survival, cranial ultrasound and cerebral palsy in very low birthweight infants: 1980s versus 1990s.

OBJECTIVE: To determine the changes in the rates of survival, cranial ultrasound abnormalities and cerebral palsy in very low birthweight (VLBW) (birthweight 500-1499 g) infants between the early 1980s and the early 1990s. METHODOLOGY: A cohort study of consecutive VLBW live births in one tertiary perinatal hospital during two distinct eras was performed at The Royal Women's Hospital, Melbourne, a level-III perinatal centre. Consecutive VLBW infants born over the 18-month period from 1 October 1980 (n = 222), and over the 12-month period from 1 January 1992 (n = 202) were identified. The main outcome measures were the proportions of live births surviving to 5 years of age, rates of cranial ultrasound abnormalities, and rates of cerebral palsy at 5 years of age. RESULTS: Over the 18 months from 1 October 1980, 68% (150/222) VLBW live births survived to 5 years of age. The survival rate rose substantially to 82% (165/202) during 1992 (odds ratio 2.1, 95% confidence interval 1.4-3.2). The survival rate increased over time more for those of 500-999 g birthweight than for those of 1000-1499 g birthweight. The rates of cerebroventricular haemorrhage (CVH) were similar inlive births and survivors from both eras, as were the rates of cerebral palsy (7.5% in 1980-82; 7.8% in 1992) in survivors seen at 5 years of age. The positive predictive value of CVH for cerebral palsy was low, but cystic periventricular leucomalacia was followed by cerebral palsy in seven of eight survivors from the 1992 cohort. CONCLUSIONS: Despite the increasing survival rate with improvements in perinatal care, including more antenatal steroid therapy and the introduction of exogenous surfactant, the rates of CVH and of cerebral palsy in survivors have not diminished.

Methylxanthines and sensorineural outcome at 14 years in children < 1501 g birthweight.

OBJECTIVES: Methylxanthines, including theophylline, have been used extensively and successfully to treat apnoea in preterm infants. However, long-term consequences of such therapy are largely unknown. The aim of this study was to determine the relationship between theophylline therapy and outcome at 14 years of age in surviving preterm children of birthweight < 1501 g. METHODOLOGY: The subjects of this study were 154 consecutive survivors with birthweights < 1501 g born from 1 October 1980 to 31 March 1982; 130 (84.4%) were assessed at 14 years of age. Outcomes included motor function, psychological test scores, and growth. RESULTS: Of the 130 children assessed, 69 (53.1%) had been exposed to theophylline; 13.0% had cerebral palsy, significantly higher than 1.6% in the 61 children not exposed to theophylline (P < 0.02). This difference remained statistically significant after adjusting for potential confounding variables including the presence of cerebroventricular haemorrhage. In contrast, after adjusting for known confounding variables, children who had received theophylline achieved higher psychological test scores. There was no association between theophylline therapy and growth. CONCLUSIONS: Theophylline therapy in the newborn period is associated with some evidence of harmful, but also helpful sensorineural effects at 14 years of age.

Antenatal corticosteroid therapy and blood pressure at 14 years of age in preterm children.

Antenatal corticosteroid therapy substantially improves the survival rate of preterm infants, with few side effects. Higher blood pressure in adulthood has been described in several animal species after exposure to antenatal corticosteroids, but there are no similar reports in humans. The objective of the present study was to determine the relationship between exposure to antenatal corticosteroid therapy and blood pressure at 14 years of age. This was a cohort study of 210 preterm survivors with birthweights of <1501 g born in the Royal Women's Hospital, Melbourne, between 1 January 1977 and 31 March 1982. Blood pressure was measured in 177 subjects (84.3%) at 14 years of age with a standard mercury sphygmomanometer. Children exposed to antenatal corticosteroids (n=89) had higher systolic and diastolic blood pressures than those not exposed to corticosteroids (n=88) [mean difference (95% confidence interval) (mmHg): systolic, 4.1 (0.1-8.0); diastolic, 2.8 (0.05-5.6)]. However, few had blood pressure in the hypertensive range. It is concluded that antenatal corticosteroid therapy is associated with higher systolic and diastolic blood pressures in adolescence, and might lead to clinical hypertension in survivors well beyond birth.

Changes in lung function between age 8 and 14 years in children with birth weight of less than 1,501 g.

We set out to determine whether lung function of children with a birth weight of <1,501 g changed relative to expectations between the ages of 8 and 14 years. We hypothesized that changes in lung function may differ between those of birth weight above and below 1,000 g. The subjects of this study were born in the Royal Women's Hospital, Melbourne. There were 86 consecutive survivors with birth weights <1,000 g born between January 1, 1977 and March 31, 1982, and 124 consecutive survivors with birth weights 1,000-1,500 g born between October 1, 1980 and March 31, 1982. Lung function was measured at both age 8 and 14 years, corrected for prematurity in 78% (67/86) of those with birth weight <1,000 g, and in 69% (86/124) of those with birth weight 1,000-1,500 g. Overall, lung function was similar to predicted values at both 8 and 14 years of age [e.g., (forced expired volume in 1 s, FEV1% predicted) at age 8 years mean 88.5% (SD 14.7) and at age 14 years, mean 94.9% (SD 13.8)]. There were significant changes, mostly improvements, in lung function between age 8-14 years relative to predicted values: FEV1 (% predicted) increased between 8-14 years of age by a mean of 6.4 (95% confidence interval, 4.4-8.3). The improvements in some lung function variables were significantly greater in those of birth weight <1,000 g compared with those of birth weight 1,000-1,500 g: improvement in FEV1 (% predicted) between age 8-14 years in infants with birth weight <1,000 g had a mean of 10.3 (SD 13.1), and in those with birthweight 1,000-1,500 g a mean of 3.3 (SD 10.1). We conclude that lung function improved significantly relative to predicted values in children of birth weight <1,501 g between age 8-14 years. The improvements were greatest in those of birth weight <1,000 g.

Bronchopulmonary dysplasia and very low birthweight: lung function at 11 years of age.

OBJECTIVE: To determine the relationship between lung function at 11 years of age and bronchopulmonary dysplasia (BPD) in very low birthweight (VLBW) children. METHODOLOGY: This study comprised 154 consecutive surviving VLBW children, divided into three groups with respect to their neonatal respiratory morbidity: group I developed BPD; group II required assisted ventilation but did not develop BPD; and group III required no assisted ventilation. Lung function tests were measured on 120/154 (77.9%) children at 11 years of age. The relationship between various lung function variables and neonatal lung disease was analysed by multiple linear regression. RESULTS: Several lung function variables reflecting airflow were significantly diminished in the BPD group (n = 15), and residual volume was significantly higher. Despite poorer lung function overall, few children in the BPD group had lung function abnormalities in the clinically significant range (n = 2[13.3%] with a forced expired volume in 1 $ < 75% predicted; n = 2[13.3%] with a forced vital capacity < 75% predicted; n = 1 [6.7%] with a residual volume/total lung capacity > 35%). There were no significant differences in lung function variables between group II (n = 41) and group III (n = 64). Changes in lung function tests between 8 and 11 years did not very significantly between the three groups. CONCLUSIONS: VLBW children with BPD in the newborn period have period have poorer lung function at 11 years of age than other surviving VLBW children without BPD, although few have lung function abnormalities in the clinically significant range.

Passive smoking and respiratory function in very low birthweight children.

AIM: To determine if an adverse relationship exists between passive smoking and respiratory function in very low birthweight (VLBW) children at 11 years of age. SETTING: The Royal Women's Hospital, Melbourne. PATIENTS: 154 consecutive surviving children of less than 1501 g birthweight born during the 18 months from 1 October 1980. METHODS: Respiratory function of 120 of the 154 children (77.9%) at 11 years of age was measured. Exposure to passive smoking was established by history; no children were known to be actively smoking. The relationships between various respiratory function variables and the estimated number of cigarettes smoked by household members per day were analysed by linear regression. RESULTS: Most respiratory function variables reflecting airflow were significantly diminished with increasing exposure to passive smoking. In addition, variables indicative of air-trapping rose significantly with increasing exposure to passive smoking. CONCLUSION: Passive smoking is associated with adverse respiratory function in surviving VLBW children 11 years of age. Continued exposure to passive smoking, or active smoking, beyond 11 years may lead to further deterioration in respiratory function in these children.

The obstetrician and the extremely immature fetus (24-26 weeks): outcome to 5 years of age.

The aims of this study were to determine the outcome to 5 years of age for fetuses 24-26 weeks of gestational age from the obstetric viewpoint, and to determine if their outcome has improved over time. Consecutive fetuses with gestational ages from 24-26 weeks born at the Royal Women's Hospital, Melbourne, during 2 separate eras, Era 1 (1977-1982; n = 198) and Era 2 (1985-1987; n = 128) were studied and their outcome to 5 years of age determined. Fetuses referred with lethal malformations or clearly dead before the onset of labour were excluded. The stillbirth rates were similar in both eras (Era 1 23.7%, Era 2 21.9%), but the proportion of survivors to 5 years of age was much higher in Era 2 (Era 1 19.7%, Era 2 30.5%, X2 = 5.0, p < 0.03; odds ratio 1.80; 95% confidence interval [CI] 1.07 to 3.04). Overall, both the proportion and the absolute number of severely disabled children fell over time; 4 children survived with severe sensorineural disability in the 5 1/4 years of Era 1, but only one child in the 3 years of Era 2. From the obstetric viewpoint, only 1.5% of total births survived with a severe sensorineural disability, no higher than the rate expected for children born at term. Fetuses born at 24-26 weeks of gestational age need not contribute disproportionately to the number of severely disabled children in the community; furthermore, their outcome is improving over time. From the obstetrician's viewpoint, survival chances rather than sensorineural outcome should dominate decision-making at these extremely preterm gestations.

Assessment of short stature in very low birthweight children.

The aims of this study of short very low birthweight (VLBW) children at or after 8 years of age were to determine: (i) if there were any unsuspected organic causes for their growth failure; and (ii) whether any children might be suitable for treatment with synthetic growth hormone. Thirty-seven of 195 (19%) VLBW children seen at 8 years had heights < 10th centile, and of these only 40% (10/25) of families offered an assessment were concerned enough to have the child fully evaluated. No child had an unsuspected organic cause of short stature. The children's parents were significantly shorter than expected for Caucasians (mean parental height s.d. score = -1.06 (s.d. 0.72), t = -5.9, P < 0.001). On average, the bone age of the short children was delayed by 14.9 months (s.d. 18.8 months) compared with chronological age (t = -3.4, P < 0.01). When compared with their parents, the children's mean height s.d. score for their bone age was not significantly different (mean height s.d. score for bone age = -0.83 (s.d. 1.3), t = 0.6, NS). Only three children qualified for treatment with synthetic growth hormone; all three had been small for gestational age at birth and had birthweights < 1000 g. In conclusion, in short VLBW children, only a minority of families and children are likely to be concerned enough about short stature to be fully assessed; an unsuspected organic cause for growth failure is unlikely, and only a few will qualify for synthetic growth hormone therapy.

Cognition, school performance, and behavior in very low birth weight and normal birth weight children at 8 years of age: a longitudinal study.

Cognition, school performance, and behavior were assessed at 8 years of age in 132 very low birth weight (VLBW) children free of major sensorineural impairments, and the results were contrasted with a randomly selected control group of normal birth weight (NBW) children. Considering their fragile beginnings, the majority of VLBW children were developing normally and were reading and performing in most academic and social areas as well as the NBW children. However, VLBW children were significantly inferior to NBW children on tests of cognition, including tests of intelligence and visual memory, and on teacher's reports of motor skills and initiative. In addition, proportionally more VLBW children (20.5%) than NBW children (5.9%) were reported by their parents to be not coping at school.