Microaesthetics of The Smile: Extraction vs. Non-extraction

To compare microaesthetics in pre- and post-orthodontic cases, treated with non-extraction and extraction treatment and assessed whether the achieved microaesthetic parameters are comparable to the proposed norms.

Quasi-experimental study.

Orthodontic Clinic, the Aga Khan University Hospital, Karachi, from January 2005 to December 2009.

Orthodontic records of 31 cases treated with non-extraction therapy and 26 cases treated with extraction of upper first premolars were selected. Patients were of Pakistani origin, aged between 12 to 30 years. Microaesthetics was assessed by measuring maxillary central incisor crown width-height ratio, connectors between the maxillary anterior sextant, gingival zenith level of the maxillary lateral incisor and golden percentage of the anterior teeth using the patients' plaster models and intraoral frontal photographs. Measurements of the golden percentage were made using the software Adobe Photoshop, whereas all other parameters were measured on the plaster casts using a digital vernier caliper. Paired t-test, independent t-test and one sample t-test were used to make comparisons within the groups, between the groups, and to compare the posttreatment values with the proposed norms, respectively. Statistical significance level was set at p ² 0.05.

A statistically significant improvement in the microaesthetic parameters was observed for both extraction and non-extraction subjects (p < 0.05) after orthodontic treatment. Values closer to the proposed norms were achieved more readily in the non-extraction group.

Microaesthetics of the smile is improved with orthodontic treatment. It is recommended that greater consideration be given to the microaesthetic parameters of the smile during the finishing stages particularly when utilizing extraction mechanics during orthodontic treatment.