Speed of Premolar Extraction Space Closure: Healed vs Recent Extraction Site

Trial design: Randomized controlled clinical trial with a split mouth design. Setting: Jordan University of Science and Technology(JUST) Postgraduate Dental Teaching Clinics and labs.

Participants and interventions: Twenty-eight subjects with bimaxillary proclination requiring extraction of all first premolar teeth participated in this study. In the lower arch, two groups were also identified; group 1 having the first premolar extracted before the commencement of orthodontic treatment and group 2 having the first premolar extracted just before space closure when 0.019 x 0.025 inch SS archwire was reached. Patients were followed-up monthly for three months. At every follow-up visit lower alginate impressions were taken. Extraction spaces in the lower arch follow-up models were measured using digital caliper.

The rate of extraction space closure in the lower arch was assessed monthly.

Inclusion criteria

• Age ≥ 16 years
• Proclined upper and lower incisors (Ui/max >115 o, Li/mand >99o)
• Mild upper and lower arch crowding (<4mm) or no crowding
• Need for upper and lower first premolars extraction
• Skeletal I malocclusion (1<ANB <5)
• Average lower facial height and maxillomandibular plane angle (22 o <MM<32 o)
• Class I canine relationship
• Good oral hygiene and healthy periodontium

Exclusion criteria

• Poor oral hygiene
• Diseases and medications that were likely to affect bone biology
• Previous orthodontic treatment
• Evidence of bone loss
• Active periodontal disease
• Smoking