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A Rahkamo

Publications and source records attributed to A Rahkamo.

15 recordsLinked to original sources
PubMed1997

Comparison between cephalometric classification methods for sagittal jaw relationships.

The present study evaluated how 2 widely used cephalometric sagittal analyses, ANB angle and WITS appraisal, classify skeletal classes I, II, and III in a random selection of 497 Finnish boys aged 4-20 years. This distribution was also compared with the visual inspection of cephalometric structures judged by 2 university instructors in orthodontics. The results showed remarkable differences and even sparked controversy concerning classification of the sagittal jaw relationships. The ANB angle and the WITS appraisal emphasized the role of class II based on a failure to distinguish the proportion of class I. The low-angle influence skewed the distribution of the ANB pattern in the class III direction, and the WITS pattern, conversely, towards class II. High- or low-angle influence had only minor effects on the visual inspection of cephalometric structures. This cross-sectional study showed an age-related decreasing mean value for the ANB angle and increasing mean value for the WITS appraisal, thus explaining the remarkable difference in the distribution of sagittal classes. However, the findings of age-related changes makes the use of the fixed norms questionable. For extreme or controversial cephalometric interpretations, visual inspection provides an essential aid in diagnosis and skeletal classification.

Adolescent↗
PubMed1989

Age and skeletal type-related changes of some cephalometric parameters in Finnish girls.

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.

Adolescent↗
PubMed1986

Effect of selenium on developing mouse teeth in culture in vitro.

First molars from 2-day-old mice were cultured for 7 days in medium supplemented with 0.04, 0.4, 4.0 parts/10(6) selenium (Se) or 10 per cent calf serum. Collagen synthesis, measured after labelling with [3H]-proline for the last 24 h of culture, was most active at 0.4 parts/10(6) Se. Supplementation with 300 parts/10(6) Se for the first 24 h of culture caused ultrastructural changes in newly-deposited enamel and dentine matrices.

Ameloblasts↗
PubMed1985

Uptake of cadmium in developing rat teeth in organ culture.

Molar teeth from 9-day-old rats were cultured for 7 days in medium supplemented with 1 or 10 ppm Cd for 1 or 3 h or 7 days. After culture the Cd concentrations were measured separately from the mineralizing parts and the cell-containing tissues. The accumulation of Cd increased with the duration of treatment and the concentration used, being more intensive in the hard parts than the soft tissues of the teeth.

Animals↗
PubMed1981

Cytotoxicity of some solutions used for root canal treatment assessed with human fibroblasts and lymphoblasts.

The cytotoxicity of seven solutions used in root canal therapy was tested in human fibroblast and lymphoblast cultures. The amount of cell damage was assessed by measuring the release of 51Cr from labeled cells into the medium. The solutions, when applied at therapeutic concentrations, displayed high toxicity in vitro and differences in cytotoxicity were seen between different solutions. Generally, lymphoblasts were found to be more sensitive than fibroblasts. The cytotoxic profiles of the two cell types resembled each other except when 5% sodium hypochlorite or 0.2% Hibitane was used. When the criterion of total cell lysis was 50% 51Cr release, the toxic concentrations of the solutions tested ranged between 1:25 and 1:900 (v/v) for fibroblasts. For lymphoblasts the corresponding concentration range was between 1:40 and 1:750. Despite technical simplicity and good reproducibility the 51Cr release method proved unreliable for testing the cytotoxicity of endodontic solutions. Because the methodological errors cannot be foreseen the 51Cr release method requires supporting evidence from other methods.

Cells, Cultured↗