The occurrence of tooth size discrepancies among different malocclusion groups.

This study consisted of 109 patients with varying malocclusions (Class I; Class II, Division 1; Division 2; and Class II surgery) who were treated orthodontically. Tooth size analyses were performed on the pretreatment models of these patients and mesial-distal tooth size ratios were measured as described by Bolton. The incidence of mesial-distal tooth size discrepancies in the malocclusion groups was analyzed and compared with Bolton's means and standard deviations. The results showed no difference in the incidence of tooth size discrepancies from one malocclusion group to another. When the sample was taken as a whole, there was no significant difference in the mean of the mesial-distal tooth size ratios as computed in the present study and compared to Bolton's mean. There were, however, higher standard deviations seen in the present study compared with Bolton's study. Even though there was no significant difference in the incidence of tooth size discrepancies among malocclusion groups, there was a large number of tooth size discrepancies in each group. Therefore it is suggested that Bolton's tooth size analysis be performed before initiation of orthodontic treatment.

Coronary artery steal secondary to coronary arteriovenous fistula.

Coronary arteriovenous fistula in adults may be associated with angina pectoris. It has been suggested that the cause of the angina is a coronary artery steal of blood into the fistula but this has not been demonstrated. To study its hemodynamics the authors describe two cases of coronary artery fistula. They discuss the use of radionuclide angiography in this setting. The surgical technique is outlined and the use of intraoperative electrocardiographic monitoring is emphasized.