Permanent teeth of 12 individuals with a 47,XYY chromosome constitution have been examined. The tooth sizes of 47,XYY males were found to be larger than those of control males and females. In many instances the differences were statistically significant. Using these results, it was possible to conclude that a factor or factors which influence excess growth of 47,XYY males probably are in effect during prenatal life, but without doubt must be in effect very early in postnatal life. The time period needed for the achievement of final excess growth is relatively short, in the case of first permanent molars probably only from 2 1/2 to 3 1/2 years. On the basis of the finding that the Y chromosome apparently carries genes affecting tooth sizes in normal males , it was suggested that gene products of the extra Y chromosome could cause the observed size difference between normal and 47,XYY males. The nature of the influence of one versus two Y chromosomes on growth was discussed in terms of the possible influence of the Y chromosome on the cell divisions within the developing tooth germ.
The aim of this study was to investigate the anatomical features of edentulous jaw dental segments (eJDS) in order to offer the most reliable clinical and radiological classification of such segments in planning for implant treatment. A total of 374 patients, 156 men and 218 women, participated in the investigation. The mean age of the patients was 46 years (SD 12.7), ranging between 17 and 73 years. The eJDS were estimated by means of orthopantomogram, computerized tomography, and intraorally with special ridge-mapping callipers for measurement of alveolar process width. A total of 792 screw-shaped and 1-stage Osteofix Dental Implant System (Oulu, Finland) implants were inserted. Dental segments were divided according to the results of the commonly accepted eJDS assessments into 3 clinical-anatomical types. Type I indicated insignificant or no atrophy of eJDS (232 patients with 476 implant sites; 60.1% of the total number). Type II indicated mild to moderate vertical or horizontal atrophy of eJDS (100 patients with 222 sites; 28% of the total number). Type III indicated significant vertical or horizontal atrophy of eJDS (42 patients with 94 sites; 11.9% of the total number). The accuracy of the clinical and radiological classification was adjudged to have been 95.8%. By the process of establishing clinical and radiological classification of the jawbone segments, more reliability was anticipated regarding the insertion of implants both in maxillae and mandibles.
The aetiology of mental retardation (MR) was studied in a population-based series of Norwegian children derived from 30 037 children born between 1980 and 1985. The study included 178 children, 79 with severe MR (SMR) (IQ
The aim of the present study was to define some cephalometric standards in a group of 217 Finnish girls from 7.0 to 18.0 years of age and furthermore to estimate the influence of the skeletal classes on these standards. Age-related changes were seen between the standards of the youngest (7.0-9.5 years) and the oldest (14.5-18.0 years) group where 9 out of 15 of the inspected angles increased with age, three of them ANPr***, SNPg** and SNB* significantly, and 6 decreased, four of them significantly: ANPg***, ANB**, NL/ML* and RL/ML*. The cranial base angles did not show any significant age-related or skeletal type-related variations. Between the skeletal groups I and II significant differences were seen in 11 variables. Between skeletal I and III groups, 7 angles were significantly different. The results demonstrate that when cephalometric standards are used, they should be derived from that population, they should be age related, and the skeletal pattern should be taken into account.
A previous study of age differences in facial morphology in a dentate sample representing young, middle, and old age (Tallgren and Solow, 1987) indicated an increase in lower anterior face height during adulthood. The aim of the present study was to examine in detail the accompanying age differences in dentoalveolar heights. The material consisted of lateral head films of 191 dentate Finnish women divided into the age groups 20-29, 30-49, and 50-81 years. The present study comprised 26 variables calculated from digitized reference points. The maxillary and mandibular anterior dentoalveolar heights were significantly larger in the middle and old age groups than in the young group, and the mean differences were of the same magnitude for the maxilla and the mandible. Analysis of the dentoalveolar components showed that in the mandible the extra-alveolar height of the incisors was significantly larger in the two older age groups than in the young group, while no significant differences were found in the maxilla. The mean differences in anterior mandibular ridge height between the older age groups and the young group were smaller than in the maxilla. No significant differences in dentoalveolar morphology were observed between the middle and the old age groups.
Identification of abnormalities in the developmental trajectory during infancy of future schizophrenia cases offers the potential to reveal pathogenic mechanisms of this disorder. Previous studies of head circumference in pre-schizophrenia were limited to measures at birth. The use of growth acceleration of head circumference (defined as the rate of change in head circumference) provides a more informative representation of the maturational landscape of this measure compared to studies based on static head circumference measures. To date, however, no study has examined whether HC growth acceleration differs between pre-schizophrenia cases and controls. In the present study, we employed a nested case control design of a national birth cohort in Finland. Cases with schizophrenia or schizoaffective disorder (N=375) and controls (N=375) drawn from the birth cohort were matched 1:1 on date of birth (within 1month), sex, and residence in Finland at case diagnosis. Longitudinal data were obtained on head circumference from birth through age 1. Data were analyzed using a new nonparametric Bayesian inversion method which allows for a detailed understanding of growth dynamics. Adjusting for growth velocity of height and weight, and gestational age, there was significantly accelerated growth of head circumference in females with schizophrenia from birth to 2months; the findings remained significant following Bonferroni correction (p
Statistical comparison of arch width, length and palatal height with age, sex, orthodontic treatment and extractions finds little correlation except a tendency for larger dimensions in males, especially in palatal width, and differences related to postextraction drift.
A random sample of non-institutionalized elderly people in Orebro County, Sweden, has been examined. The present report studies marginal bone levels in this population. Measurements were made on intra-oral radiographs. The marginal bone levels of the teeth were measured in fifths between the apex and a point 1 mm apical to the cemento-enamel junction. More than 87% of the teeth received a bone score 1 or 2, which indicates that more than 60% of the original bone level was remaining. About half of the teeth were given the bone score of 1, i.e., having more than 80% of the original bone level intact. For those subjects receiving regular dental treatment, the average bone level index (mean bone score for the subject) was lower than for the others. The general bone level of a subject is described by a classification which takes into consideration only the best 70% of the teeth. Using these bone level classes, people aged 65-74 years positively differ from older groups. The % of subjects belonging to the better bone level classes increases with increasing number of remaining teeth. In a multiple stepwise regression analysis, the number of teeth is the only predictor having significant correlation to bone level index. A variable such as regular treatment in itself seems to have little influence.