Sagittal Space Relations in the Maxilla during Molar Eruption

Abstract

The aim of this study was to measure the space relations in the maxilla during upper molar eruption, and to interpret associations. 154 skulls ranging from infant to adult were measured on the basis of defined distances. The age of the skulls was determined by tooth development. The data were compared and qualitatively interpreted. We observed that, immediately after eruption of the primary dentition, there was nearly enough space in the upper jaw for the first permanent molar. Yet eruption does not occur until the age of 5 to 6 years, at the beginning of the first transition phase. As opposed to the first permanent molar, the second erupted as soon as there is enough space in the upper jaw. This tends to happen at the end of the second transition phase at ca. 12-13 years of age. We noted that there was almost enough space in the maxilla until the age of 17 to accommodate all the teeth in the upper jaw. According to our measurements, growth at the posterior edge of the maxilla also took place after eruption of the third molar. This leads us to consider that we can postpone the extraction of the upper third molars until after the 18th year, and to consider the possibility that the upper third molar may erupt correctly while the maxilla is still growing. It is precisely this trend that is significant in clinical practice, since maxillary wisdom teeth are often extracted prematurely due to an apparent lack of space.