Normal eruption of the maxillary canine quantified in three dimensions.

The normal eruption path of maxillary canine teeth was quantified on annual lateral and depressed postero-anterior cephalometric radiographs of 15 females and 15 males aged 5-15 years. The lateral view was rotated so that the horizontal coincided with the Frankfort plane on the depressed views, thus orientating the two views in space. Successive positions of canine cusps were marked on tracings of both views superimposed on the anterior outline of the zygomatic process. All positions of the canine cusps were digitized and the horizontal, vertical and lateral annual differences found by subtraction, taking the first position of the canine as the origin. The chronological data were corrected for enlargement and adjusted to increments of 12 months. Adjustments were also made to take into account varying ages of eruption. Posterior movement occurred between 7 and 13 years (all three years before eruption, the year of eruption and the following year). Vertical movement occurred between 5 and 13 years (all of the six years before eruption, the year of eruption and the following year). Lateral movement tended to be in a palatal direction up to 2 years before eruption followed by significant buccal movement in the year before eruption, the year of eruption and the following year. Data are given for eruption in three planes.