The Incidences And Complications Of Permanent Second Molar Eruption Disturbances

To reveal the incidences of permanent second molars (PM2) eruption disturbances in China and its related complications by radiological analysis. Panoramic radiographs from 15530 patients in 2023 were enrolled and analysed. The patients' gender, age, caries or fillings in the distal of permanent first molars (PM1) or the mesial of PM2, alveolar bone resorption (RAB) between PM1 and PM2, root resorption(RR) of PM1 were recorded in all the cases. Cases with PM2 eruption disturbances were screened according to the angle formed by the long axis of PM2 and PM1 and the vertical distance from the PM2 to the occlusal plane of PM1. Then the angle of eruption disturbances (Ang) and the depth of eruption disturbances (Dep) were further measured. Type of PM2 eruption disturbances and quadrant distribution were recorded on the chart. The overall incidence of PM2 eruption disturbances at the individual level was 7.71% (1197/15530).The total incidence of complication (RAB, caries and RR) in the PM2 eruption disturbances group was 52.84% (902/1707), which is significantly higher than that of the PM2 normal group (6.33%(796/12580), P<0.05. ). Age, type of PM2 eruption disturbances were highly related to these complications. The above findings suggest that PM2 eruption disturbances should be given high priority in clinical practice, especially in patients older than 26 years old and those PM2 with an eruption disturbances angle in the range of 11º to 80º .