The sequence of replacement of deciduous teeth by permanent teeth in the lateral maxillary segments and its clinical significance. Authors’ own observation

Introduction
The formation of permanent tooth buds and their movements in the bone resulting in their eruption in the oral cavity in a strictly defined place and time is a long-lasting and complex process. The period of replacement of deciduous teeth by permanent teeth is crucial for the formation of correct relationships in and between the arches. It lasts about six years. Most developmental disorders develop during this time.

Aim
The aim of this study was to investigate which sequence of replacement of deciduous teeth by permanent teeth in the lateral maxillary segments is the most common and to analyse the factors affecting associated differences. An attempt was also made to evaluate the clinical outcomes of two patterns of teeth replacement observed in this region.

Material and methods
The material consisted of medical records, especially panoramic radiographs, of patients aged between ten and twelve years treated in an orthodontic clinic in Opole.

Results
The study showed that the replacement pattern of 4–5–3 was the most common in the whole group. However, there were significant differences observed between various sex groups: in 68.9% of boys maxillary teeth were replaced in this sequence, while in 55.8% of girls the replacement pattern of 4–3–5 was observed.

Conclusions
The specialist literature shows more opinions that the 4–3–5 pattern is the normal replacement pattern. When the canine erupts earlier than the second premolar, it may indicate disorders involving the second premolars. The sequence of tooth replacement should be monitored in detail by clinicians even at the pre-eruptive stage, because early and skilful intervention can contribute to proper alignment of teeth in the arches and correct relationships between the arches.