Title There may not be any clinically significant difference in facial profile change when comparing first premolar extractions to second premolar extractions.
Clinical Question In a child with insufficient space for the permanent dentition, does extraction of second premolars affect the facial profile less than extraction of the first premolars? 
Clinical Bottom Line There may not be any clinically significant difference in facial profile change when comparing first premolar extractions to second premolar extractions. A case-control and a non-randomized clinical trial come to similar conclusions that there is very little clinical difference in the soft-tissue changes seen when all first premolars or all second premolars are extracted.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
12940559Wholley/2003 Adolescents orthodontically treated with edgewise appliances along with 4 premolar extractions. Case-control
Key resultsWholley and colleagues determined that there were no significant differences in the mean upper or lower lip change with respect to PM line or a constructed anterior reference line between groups 4/4 (those having four first premolars extracted) or 5/5 (those having four second premolars extracted). However, the results did vary widely. Group 4/4 had a mean upper lip change of -0.48 mm (range of +1.26 to -2.2) with respect to PM and +0.15mm (range of +3.1 to -3.1) with respect to the anterior reference. Group 4/4 had a mean lower lip change of -0.31mm (range of +4.38 to -4.69) with respect to PM and +0.66mm (range of +2.4 to -1.2) with respect to the anterior reference. Group 5/5 had a mean upper lip change of -0.47 mm (range of +1.12 to -2.52) with respect to PM and +0.01mm (range of +1.7 to -2.0) with respect to the anterior reference. Group 5/5 had a mean lower lip change of -0.07mm (range of +2.57 to -2.31) with respect to PM and +0.89mm (range of +5.7 to -1.2) with respect to the anterior reference.
9387833Steyn/1997 Adolescents orthodontically treated along 4 premolar extractions Non-randomized clinical trial
Key resultsSteyn and colleagues report that there is very little difference in facial profile change between extraction of first premolars (group 44) and extraction of second premolars (group 55) with respect to Nasion and NPo. No confidence interval or p values were given. The mean difference of upper incisor retraction between group 44 and group 55 was 0.2mm when measured from nasion and 0.5mm when measured from NPo. The mean difference of lower incisor retraction between group 44 and group 55 was 0.5mm when measured from Nasion and 0.8mm when measured from NPo. No ranges for these values were provided.
Evidence Search (((First[All Fields] OR Second[All Fields]) AND "Bicuspid"[Mesh]) AND "Tooth Extraction"[Mesh]) AND "Cephalometry"[Mesh]
Comments on
The Evidence		 The Wholley article is a case-control in which 80 adolescent orthodontic patients all had 4 premolars extracted as part of their treatment. These patients were either treated with four first premolar or four second premolar extractions. The groups were similar at the start of treatment and were treated with the same method by the same orthodontist. No competing interests were reported. The Steyn article is a non-randomized clinical trial in which 147 adolescent orthodontic patients all had 4 premolars extracted as part of their treatment. These patients were either treated with four first premolar or four second premolar extractions. The groups were similar at the start of treatment and were treated with the same method by the same orthodontist. There was no report of any patient attrition and followup and compliance appear to be adequate. Recall bias is unlikely and no competing interests were reported.
Applicability Based on the evidence presented above, it can be concluded that for the average patient, the clinician should not expect the effect on the facial profile to be significantly different when extracting four first premolars as opposed to four second premolars. The decision of which premolars to extract should be based then on the rest of the patient’s clinical history. It should be noted that more and better evidence is still needed with respect to this topic.
Specialty (Orthodontics)
Keywords Orthodontics, Premolar extractions
ID# 2424
Date of submission 02/28/2013
E-mail Meason@livemail.uthscsa.edu
Author Kyle Meason
Co-author(s)
Co-author(s) e-mail
Faculty mentor Clarence C. Bryk, DDS, MS
Faculty mentor e-mail BRYKC@uthscsa.edu
   
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
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Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs)
None available