| Popis: |
Introduction: due to its long duration, the process of eruption of permanent dentition may be affected by a number of systemic and/or local factors. Objective: identify the initial age for the eruption of the first permanent molars and the moment of their occlusion among students from a school located south of Mexico City. Methods: a longitudinal descriptive study was conducted at Espartaco elementary school south of Mexico City. The study sample consisted of 53 students (31 girls / 22 boys) whose parents granted their informed consent. The variables studied were sex, chronological age and eruption of the first permanent molars. The sample was checked every three months by two qualified examiners in a well-lit place using dental mirrors. The following criteria were applied: unerupted, initial eruption and functional occlusion. Further examination was performed to include all occluded molars. Estimation was made of central tendency and dispersion measures by chronological age (initial eruption and functional occlusion), as well as the average duration of the eruption process. Data were processed with the statistical software SPSS version 21. Results: initial eruption age was the following: 6.69 years for the first permanent upper right molars, 6.68 for the upper left, 6.67 for the lower right, and 6.59 for the lower left. The first molar to occlude was the upper right (7.29 years) and the last ones were the two lower molars (7.56). Overall average time to reach occlusion was 0.6 year for the upper right molar, 0.7 for the upper left, 1.1 for the lower right and 1 year for the lower left. Conclusions: in the population studied average age for the start of eruption of the first permanent molar was 6.6 years. Among boys the first lower molars are the ones that start eruption and the last to reach occlusion. |
