Physiological tooth migration and its significance for the development of occlusion

Dan Boboia

Article Review 10/2/09

Title: Physiological tooth migration and its significance for the development of occlusion

Author: Louis Baume

The Journal of Dental Research: August 1950, Vol. 29, #4

Major Topic: Assessing the relationship between the degree of overbite of the deciduous dentition and that of the mixed permanent dentitions and the factors responsible for transitory change, if any, from the deciduous overbite to the permanent overbite in the same individual.

Methods:

52 series of plaster casts were made before and after eruption the permanent incisors. Each cast was classified according to degree of overbite as checked from the lingual aspect of plaster reproductions in occlusion. Overbite was classified as slight, medium, or severe:

slight – incisal edges of mnd. 1^st incisors met the upper incisal 1/3 of the crowns of the opposing maxillary incisors

medium – lower 1^st incisors occluded with the middle 1/3 of the upper incisor crowns

severe – the mandibular incisors met the protuberance of the cingulum or came in contact with the gingiva

Measurements were made if the length of the frontal portion of the upper and lower arches in deciduous and mixed dentition.

Deciduous:

Slight OB: 40% cases

Medium: 29% cases

Severe: 31% cases

Mixed:

Slight:19%

Medium: 27%

Severe: 54%

Findings:

Data reveals that during the transition from a deciduous to mixed dentition a developmental tendency toward the formation of a deeper bite occurs.

Summary:

1) Degree of incisal OB in the permanent dentition primarily was determined by the extent of mandibular forward growth which occurred during the eruption of the successional teeth. The lessened forward extent of the mandibular arch was responsible for a greater incidence of severe overbite in the mixed dentures.

2) The deciduous overbite was also a determining factor in that the slight overbite tended to increase during the period of the mixed dentition while a severe overbite became worse.

3) The definite overbite of the permanent dentition finally depended upon the eruption sequence of the permanent canines and premolars. If in the lower arch the sequence was canine, first premolar, second premolar and in the upper arch first premolar, canine, and second premolar, the best results were observed.

4) Incisal overbite developed independently of the mechanism of molar adjustment.

Assessment:

Well written; a good read!