Department of Pedodontics, Cariology and Endodontics, Institute of Dentistry, University of Oulu and Oulu University Hospital, Oulu, Finland. marjut.korhonen@oulu.fi
The aims of this study were to test the suitability of normal dental records in determining the eruption times of teeth and to compare the retrospective longitudinal DMF values with the statistical cross-sectional means. Patient records for two cohorts (1970 and 1980) were collected from three Finnish towns. The study population comprised 1910 children. The eruption times of the permanent teeth, DMFT and DMFS curves (excluding F due to fractures and M due to orthodontic reasons) were investigated for the year of examination in different study locations. The cross-sectional DMF values were compared to longitudinally calculated data. Tooth eruption was earlier in girls than in boys. However, girls did not have significantly higher DMF values than boys. In all towns, dental health was significantly better in the 1980 cohort than in the 1970 cohort. Comparison of the cross-sectional DMF values in the municipal health center statistics showed that the mean statistics gave considerably higher values than the measured values did after 15 years of age. The inconsistency between measured longitudinal DMF values and the cross-sectional statistical DMF values indicates the importance of creating computer programs for analyzing data longitudinally from normal dental records.
OBJECTIVES: The effects of protein deficiency and sucrose on formation and mineralization of dentine and dental caries in the molars of young rats were investigated. MATERIALS AND METHODS: Two groups of weaning Wistar rats received raw soy flour to induce protein deficiency with sucrose or starch as the carbohydrate source; the other two groups received skim milk powder as the protein source with sucrose or starch as the carbohydrate source. At the onset, tetracycline was injected to mark the dentine formed at that moment. After 6 weeks, lower molars were sectioned sagittally, and the areas of dentine formation and dentinal caries developed during the experiment were quantified separately in the first and second molars. Dental caries was also classified according to Schiff's reaction. Calcium (Ca), phosphorus (P) and total mineral elements were analyzed using an electron probe microanalyzer. RESULTS: Rats in both protein-deficient groups and normal protein sucrose group had significantly larger areas of dentine formed compared with rats fed with normal protein starch diet. Ca, P and total mineral elements in dentine were significantly reduced by normal protein sucrose diet. P content was significantly reduced in dentine of rats in protein-deficient sucrose group. Rats in normal protein sucrose group had significantly more and larger dentinal caries lesions than in any other group. CONCLUSION: This study suggests that protein deficiency induced by soy prevents the progression of dental caries even in highly cariogenic environment.
The effectiveness of fissure sealing in preventing dental caries in a subject-specific fashion was studied in order to forge a link between the controlled trials and knowledge creation in clinical practice.
The subjects were divided retrospectively into three categories according to the sealant treatment status of their first permanent molars at the first examination after the eruption and the survival of first molars in each group were estimated using the Kaplan-Meier method.
Sealing of all first molars in caries-prone subjects was an effective caries preventive method. The highest survival of first molars was observed in the unsealed subjects in the health center focusing on sealing risk-subjects only. The first molars of partly sealed subjects had the lowest probability of survival in both health centers.
Sealing all four permanent first molars rather than some of them in high caries risk subjects and leaving unsealed the first molars of caries resistant subjects enable to decrease unnecessary sealant treatment by focusing it especially to those benefiting it.
The aims of this study were to test the hypothesis that existing patient records serve as a source of data for survival analysis of dental health and to develop a system for routinely conducted survival analysis of dental health from tooth eruption to first caries attack. Patient records for three cohorts were collected from four towns in Finland: Oulu, Turku, Kuopio, and Kemi. The study population comprised 2103 children born and living in these towns. The Kaplan-Meier curves for dental caries were drawn separately for each tooth and for the maxilla and mandible (for each age cohort). Placements of the first restoration of all teeth in each age cohort were investigated. The 1960 cohort had an extremely high post-eruptive morbidity in all teeth. The 1970 cohort had relatively high immediate post-eruptive morbidity in both molars, but much lower than that of the 1960 cohort. The filling increment rates for second molars were lower than those of the first molars in the 1970 cohort. Characteristic of the 1980 cohort was a rapid increase in the caries increment of the premolars and second molars 4 years after eruption. The results indicate a big difference in tooth-by-tooth dental health in Finland. A huge decline in caries attack was seen from the 1960 cohort to the 1980 cohort, but a deterioration of dental health in premolars and second molars is clearly seen in the 1980 cohort in the 1990s.
