Final answer:
Class I mobility describes slight horizontal tooth movement of less than 1mm and is considered within the normal range. It is not pathological. Deciduous teeth emerge in infancy, permanent teeth from age 6, and wisdom teeth between 17 and 25 years.
Step-by-step explanation:
Class I mobility is a term used in dentistry to describe slight horizontal movement (less than 1mm) of a tooth when a force is applied. It indicates that the tooth has a normal range of movement and is not considered to be a pathological condition.
In contrast, class II mobility would indicate a moderate movement greater than 1mm but less than 2mm, and class III mobility indicates severe movement beyond 2mm or vertical displacement. The teeth numbers mentioned (#2, #13, #15, and #20) refer to specific positions in the dental arch according to the Universal Numbering System used by dentists in the United States.
Regarding the chapter summary review, deciduous teeth, also known as baby teeth, generally emerge during infancy, permanent teeth begin to appear around age 6 and continue until adolescence, and wisdom teeth generally emerge in late adolescence or early adulthood, typically between the ages of 17 and 25.