Orthodontics Space Creation and Smile Features

Space Creation

• Derotation of posterior teeth creates space
• Proclining incisors creates space
• Retroclining incisors does not create space
• Expansion creates space

Normal Smile Features

• Upper incisors do not touch lower lip and run parallel to it
• Width of smile displays at least upper first premolars
• Whole of the upper incisor are showing with interproximal gingiva
• Width of smile displays at least upper second Molar is NOT a feature of a normal smile

Spontaneous Movement

• Spontaneous movement is greater in growing children
• Spontaneous movement is less in adults
• Spontaneous movement is increased when extractions are carried out prior to eruption of adjacent teeth
• Spontaneous movement is increased if no occlusal interferences are present

Retained Deciduous Mandibular Incisors

• Causes lingual eruption of permanent mandibular incisors

Space Analysis

• Positive value indicates space deficiency
• Space discrepancy is calculated from space available minus space needed
• Negative value indicates excess space

Class I Malocclusion

• In crowded Class I malocclusions, extractions in both arches are preferred to discourage the development of one arch more than the other
• Expansion is not always the treatment of choice in crowded dentition
• Fixed appliances are not always the treatment of choice in crowded dentition

Serial Extraction

• Aims to intercept developing arch-length deficiency and reduce/eliminate extensive appliance therapy needs

Arch Length Discrepancies

• The most likely malpositioned tooth in a mandibular arch length discrepancy is the 2nd premolar

Crowding Relief

• Most spontaneous improvement occurs within the first 6 months after extractions