The mixed dentition period spans the period where both primary and
permanent teeth are present. This period of dental development requires complex
coordination between resorption of primary tooth roots, alveolar bone development and
eruption of succedaneous permanent teeth. A thorough knowledge of dental arch
dimensions changes, as a result of growth and development, is of paramount
importance to the clinician. The purpose of this chapter with the question-answer
format is to provide in depth the relationship between the tooth eruption pattern and
dental arch changes during the transition from mixed to permanent dentition. In the
second part of the chapter, through clinical examples and a problem-based approach, a
thorough knowledge of the tooth eruption sequence, as well as tooth eruption
abnormalities and arch space loss is provided.
Keywords: Dental arch length, Dental space deficiency, Late mesial shift,
Leeway space, Mixed dentition, Tooth development.
