Mechanism of Human Tooth Eruption: Review Article Including a New Theory for Future Studies on the Eruption Process
Drawing and radiograph showing a primarily retained permanent first molar. The cause is the crown follicle’s lack of ability to destroy the overlying osseous tissue (blue arrow on the drawing). The upper radiograph shows primary retention of the left mandibular first molar from a 10-year-old boy. The bottom two panoramic radiographs from the same girl, aged 8 years and 8 months (left) and 10 years and 8 months (right). The two radiographs show that surgical exposure of the left maxillary first molar after the left radiograph was taken results in eruption of the tooth (right). At the same time, the radiographs show that the second maxillary molar in the field where the primarily retained tooth was located is delayed in formation. The condition in the left maxillary molar field has thus affected both eruption and formation of the teeth. The condition may be connected with a virus infection during the first years of the patient’s life.