ABSTRACT
A statistical exploration of space changes following early loss of deciduous molars, developing a picture of closure from both directions with district differences between upper and lower arch changes.
Subject(s)
Molar/physiopathology , Tooth, Deciduous/physiopathology , Age Factors , Cephalometry , Child , Cuspid/physiopathology , Dental Arch/anatomy & histology , Dental Caries/physiopathology , Humans , Malocclusion/classification , Malocclusion/etiology , Malocclusion/therapy , Mandible/anatomy & histology , Maxilla/anatomy & histology , Mesial Movement of Teeth/complications , Mesial Movement of Teeth/physiopathology , Models, Biological , Molar/anatomy & histology , Time Factors , Tooth Exfoliation/physiopathology , Tooth Extraction/adverse effects , Tooth Movement Techniques , Tooth, Deciduous/anatomy & histologyABSTRACT
Using data collected by the National Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the author paired on characteristics of their first study pregnancy 319 white women who reported a change in smoking habits for two successive pregnancies with 319 women who reported no change in smoking behavior. Matching was based upon similar birth weight, interval between births, smoking behavior, sex, and parity of the first of two study births. Divergent smoking behavior for each pair by the time of the second study birth allowed assessment of smoking as a treatment effect. Members of each pair who started smoking prior to the second birth while not smoking for the first, had infants with an average birth weight of 67 g less than infants of their controls who did not start smoking and 36 g less than their previous infant. Among infants whose mothers reported smoking prior to the first study birth, a significant increase in birth weight was observed over infants of controls for women who quit smoking prior to the second study birth (average, 169 g). Taken at face value, this rebound in birth weight is not consistent with an immutable, innate predisposition to lower birth weight among those disposed to smoking.
Subject(s)
Birth Weight , Pregnancy , Smoking , Adult , Female , HumansABSTRACT
By means of computer-based statistical methods, several types of Class II malocclusion have been discovered with defining horizontal and vertical characteristics. Of the six horizontal types, four are severe syndromes, one is a loose, ill-defined grouping of cases with mild skeletal features, and one has only the dental features of Class II. Five vertical types associates with Class II were also revealed, although each vertical is not associated with all horizontal types. A simplified simulation of the computerized procedures has been developed for routine use in clinical practice.
