The experimental verification of the efficacy of finite element modeling to dental implant systems.

In vitro experimental data of angular displacement vs. applied force were obtained on a fully osseointegrated pair of endosseous implants in a mandible of a macaca mulatta monkey. These data are compared with calculated displacement data for a given force from a three-dimensional finite element model reproducing the geometric structure of a portion of the mandible holding the implants. The displacements show agreement over a range of forces in the elastic region within 3%. The FE model yields a full description of the bending of the implant and the distribution of the stress in the bone surrounding the implants.

Psychopathology, family functioning, and cognitive style in urban adolescents with suicide attempts.

This study examined psychopathology, family functioning, and cognitive style in 121 African-American adolescents who attempted suicide. Group means suggested that these youths, when taken together, were not reporting significant psychological distress. However, after classifying the youths into three groups by level of depressive symptoms interesting findings emerged. Youth self-reports of depressive symptoms on the Children's Depression Inventory were associated with the presence of internalizing and externalizing disorders on the Youth Self-Report and Child Behavior Checklist, and with a maladaptive attributional style. Sixty-seven percent of participants classified their family types as maladaptive in terms of levels of cohesion and/or adaptability. In fact, the majority of adolescents and parents reported their families as disengaged. These findings are discussed from a culturally and developmentally sensitive framework which considers key demographic variables (race, socioeconomic status, age). Clinical implications are offered for individual and family interventions.

Comparative three-dimensional analysis of two finite-element endosseous implant designs.

The finite-element method was used to assess force distribution to the cortical and cancellous bone surrounding two HA-coated, cylindrical implant designs, one grooved, the other smooth-sided. It was shown that, with both designs, large compressional stresses occurred in a small volume of bone at the coronal portion of the mandibular ridge. The stresses produced gave rise to a large stress gradient in the interface area. Significant differences were noted between the two designs in this area. It was also noted that the majority of the loading occurred in the cortical region of the mandibular ridge.

Temperature rise at root surface during post-space preparation.

This study compared the changes in temperature at the root surface of extracted human central incisors during post-space preparation using the following reamers (1) Peeso, (2) Kurer, (3) Gates-Glidden, (4) Para-Post, and (5) diamond burs. A mean temperature rise ranging from 2.3 degrees C to 15.6 degrees C from the baseline of approximately 28 degrees C was recorded. Peeso reamers recorded the highest temperatures followed by Kurer system and diamond burs, whereas Gates-Glidden and Para-Post systems were the lowest.

Psychopathology in urban female minority adolescents with suicide attempts.

This study examines the level of psychopathology in 53 African-American females who attempted suicide by ingestion. Parents completed a measure of adolescent psychopathology, and the youths completed measures of depression and psychopathology. Overall, the results suggested that these youths were not experiencing significant emotional distress. However, after classifying the youths into four groups by their self-reported level of depression, the incidence of parent- and youth-reported psychopathology varied. More significant levels of depression corresponded to significant internalizing difficulties, as reported by the adolescent, and myriad psychopathological difficulties, as reported by the parents. These results are discussed from a clinical perspective with a developmentally and culturally sensitive focus. Disposition decisions must consider the level of psychopathology reported by child and parent, the family's willingness to participate in outpatient treatment, and the degree to which the adolescent and her family acknowledge the significance of the suicide attempt.

Comparison of the marginal fit of various ceramic crown systems.

This study evaluated the marginal fit of four ceramic crown systems, (1) metal ceramic crowns with a metal margin, (2) metal ceramic crowns with a porcelain facial margin, (3) Cerestore crowns, and (4) Dicor crowns. Measurements of the marginal adaptation were recorded from the facial and lingual margins by using a video-enhanced microscope with digital micrometer and image intensification in a high resolution television screen. Results indicate that all four crown systems yielded comparable and acceptable marginal fit.