CHRONOLOGY AND ERUPTIVE SEQUENCE OF THE FIRST TRANSITIONAL PERIOD TO PERMANENT DENTITION

Abstract: Introduction: Knowledge of the chronology and sequence of dental eruption due to its relationship with the growth of the jaws and development of occlusion is essential in pediatric dentistry to define diagnostic, prevention, and treatment criteria. Objectives: To estimate the mean age of eruption of upper and lower permanent first molars (1°M), central incisors (CI), and lateral incisors (LI) in children from the City of Buenos Aires (CABA). To compare the mean eruption of each tooth between sexes, maxillary and mandibular arches, and contralateral counterparts. To identify the eruptive sequence for each maxilla. Materials and methods: Observational, prospective, and cross-sectional study that included upper and lower permanent 1°M, CI, and LI of all children of both sexes between 5 and 10 years old who requested care (March-August 2023) in FOUBA and 4 CABA clinics. A tooth was identified as present when at least one cusp or incisal edge had crossed the gingival epithelium (Carr 1962). The Kärber method was used to estimate the mean eruption ages. Confidence intervals (C.I.) of 95% were calculated, and for comparisons, a significant difference (p<0.05) was assumed if none of the C.I. of one of the two means contained the other mean. The eruption sequence was obtained by ordering the mean ages. Results: 643 children were analyzed (344 female), mean age of 8.25+1.33. The first tooth to erupt was the lower right CI, 5.91 years (5.75-6.08), and the last were the upper LIs, 7.77 years (7.63-7.9). The lower incisor group erupted before their corresponding upper maxillary group (p<0.05). No significant differences were observed between upper and lower 1°M or between right and left hemi-arches. The upper LIs erupted significantly earlier in girls than in boys. The eruption sequence for both sexes was lower jaw CI, 1°M, LI, and maxilla 1°M, CI, LI. Conclusion: In this sample from CABA, it was observed that in both sexes the eruption of the permanent teeth began in the lower jaw, by the central incisors, followed by the first molars and lateral incisors. In the upper arch, the first molars erupted before the incisor group. Only the upper lateral incisors were earlier in girls.