Occurrence of malocclusion in attritive environment: a study of a skull sample from southwest Finland

Abstract – Occlusal variation and occurrence of malocclusion were examined in a Finnish skull sample derived from the 15th and 16th centuries. The material consisted of 207 adult individuals; 141 maxillas and 159 mandibles, including 93 pairs, were in observable condition. In the skull sample, only dental anomalies were observed; no skeletal malocclusions were found. The frequency of an Angle Class I lateral relationship was 97.7%. The mean values for overjet and overbite were 1.6 and 1.4 mm, respectively. A comparison with present-day Finns revealed that the skull sample showed less variation in all occlusal variables studied. An Angle Class II type occlusion, deep bite, crowding, spacing, and lateral crossbite occurred with significantly lower frequencies in the skull sample than in the present-day Finns. Advanced dental wear in the skull sample shows that a hard and attritive diet was eaten at that time. It is suggested that a dietary transition from hard to soft food is the most probable cause of the increased occlusal variation and high frequency of malocclusion in present-day Finns.     

One Turn More: Threshold Superiority of 3-turn versus 2-turn Screw-in Myocardial Electrodes

Epicardial electrodes are an alternative for patients in whom the transvenous approach presents technical difficulties. We have had clinical experience with two types of myocardial sutureless electrodes inserted in the anterior left ventricular wall: the 3-turn screw-in electrode (Medtronic 6917) was used in 209 patients from 1974 to 1977 and the 2-turn screw-in lead (Medtronic 6917 A) was used in 61 patients from 1978 to 1981. The initial threshold was equal and acceptable with both types of electrodes. During a follow-up period (up to 48 months), critical elevation of the pacing threshold resulting in exit block was found in 12% (25) of the patients with the 3-turn screw-in electrode and in 20% (12) of the patients with the 2-turn electrode (p less than 0.05). Elevation of the pacing threshold developed fairly early, usually within 6 months, with the 2-turn screw-in electrode, but much later, within 2-4 years, with the 3-turn electrode. During a longer follow-up time of up to 96 months the frequency of exit block increased up to 16% with the 3-turn electrode. Our results indicate that late critical elevation of the pacing threshold is surprisingly frequent with screw-in electrodes inserted into the left ventricular myocardium, and it is especially common with the 2-turn screw-in electrode.     

Magnetocardiographic QT Interval Dispersion in Postmyocardial Infarction Patients with Sustained Ventricular Tachycardia: Validation of Automated QT Measurements

T dispersion is a measure of heterogeneity in ventricular repolarization. Increased ECG QT dispersion is associated with life-threatening ventricular arrhythmias. We studied if magnetocardiographic (MCG) measures of QT dispersion can separate postmyocardial infarction patients with and without susceptibility to sustained VT. Manual dispersion measurements were compared to a newly adapted automatic QT interval analysis method. Ten patients with a history of sustained VT (VT group) and eight patients without ventricular arrhythmias (Controls) were studied after a remote myocardial infarction. Single-channel MCGs were recorded from 42 locations over the frontal chest area and the signals were averaged. QT dispersion was defined as maximum — minimum or standard deviation of measured QT intervals. VT group showed significantly more QT and JT dispersion than Controls. QT_apex dispersions were 127 ± 26 versus 83 ± 21 ms (P = 0.004) and QT_end dispersions 130 ± 37 versus 82 ± 37 ms (P = 0.013), respectively. Automatic method gave comparable values. Their relative differences were 9% for QT_apex and 27% for QT_end dispersion on average. In conclusion, increased MCG QT interval dispersion seems to be associated with a susceptibility to VT in postmyocardial infarction patients. MCG mapping with automated QT interval analysis may provide a user independent method to detect nonhomogeneity in ventricular repolarization.     

Leisure-time physical activity is inversely related to risk factors for coronary heart disease in middle-aged Finnish men

Coronary risk factors and levels of physical activity at leisurewere measured in a random sample of 3975 men 25–64 yearsof age residing in four areas of Finland. An index of leisure-timephysical activity (LTPA) as the product of weekly exercise sessionstimes their usual intensity (expressed as metabolic equivalents)was computed. It showed a graded, inverse association with meanarterial blood pressure, smoking and serum thiocyanate, coronaryheart disease risk estimate (combining blood pressure, totalcholesterol and smoking), and a nonlinear favorable associationwith serum lipoproteins. In multiple regression analysis, LTPAcontributed significantly and independently to the variationin mean arterial pressure; the standardized regression coefficientswere –0.06 for LTPA, 0.09 for weekly alcohol consumption,0.25 for body mass index, 0.25 age. In the regression of coronaryrisk estimate, the standardized regression coefficients were–0.19 for LTPA, 0.22 for weekly alcohol consumption, 0.09for body mass index, 0.15 for age. There was no evidence thatLTPA above 2000 kcal of weekly energy expenditure was associatedwith further reduced coronary risk factor levels. These findingsthus support the inverse direction of the association betweenexercise and coronary risk factors but they also point towardsan independent, but modest, role of leisure-time physical activityas determinant of coronary risk estimate and blood pressure