by John Mew

John Mew’s List of References, boiled-down to:

Seven Articles and Studies Involving Extractions and the Possibility of Facial Damage:

References are placed alphabetically:

1.      Bishara, SE, and Jakobsen, JR.  1997. "Profile changes in patients treated with and without extractions: Assessments by lay people". American Journal of Orthodontics and Dento-facial Orthopedics. 112: 639-644.  "When based on proper diagnostic criteria the post treatment changes in the facial profile were perceived as favourable in both the extraction and non-extraction Class II division 1 groups when compared to the pre-treatment profile". 44 subjects were selected from "well treated" patients and "poor" treatment results were excluded. "Photographs in which there was evidence of mentalis muscle activity (puckered or flattened chin) were excluded".  This obviously excluded those with open mouth postures from the final results although this exclusion does not seem to have been applied at the start of the study. (Facial damage)

2.      Clark, JD, Kerr, WJS, and Davis, MH. 1998.  "Surgery, Growth Modification or Orthodontic Camouflage? Brian's case".  Dental Update. 25:12-17.  This is the result of a survey of British orthodontists who were asked from the records how they would treat this eleven year old boy with a class II division 1 case with a complete overjet of 11mm.  Only the lower arch was crowded. Although the cheeks were obviously flat they comment "Severe class II is overwhelmingly due to mandibular deficiency".  "63% were certain that extra-oral anchorage would be required".  91% of orthodontists recommended extractions (87% in the uncrowded upper arch). (Facial damage)

3.      Harris EH, Gardner RZ, and Vaden JL. 1999.  American Journal of Orthodontics and Dentofacial Orthopedics 115:77-82.  36 patients selected from those willing to be recalled on two occasions up to 15 years after treatment.  All were premolar extractions.  “Effective midface length remained statistically unchanged during treatment but increased (< 001) an average of 3.0 mm by the first recall examination.  Midface length continued to increase (x = 1.1mm) from the first to second recall”.  The maxilla retruded 2.5mm during treatment.  “Lower anterior face height increased an average of 3.3 mm and 4.8 mm respectively” during the two following periods.  “FMA remained statistically unchanged during treatment but decreased an average of 1.6 by the first recall”. (JM assumes this was due to remodelling).  The mandible rotated forward after treatment, JM thinks due to lip seal and possibly case selection. (F damage)

4.      Kahl-nieke.B, Fischback.H, and Schwarze.C.W.  "Post retention crowding and incisor irregularity: A long-term follow-up evaluation of stability and relapse". BJO.22: 249-257. 1995.  An interesting follow-up of 1464 patients of whom 299 participated.  Congenitally absent and traumatically missing lost incisors were excluded and 95 male and 131 females finally included.  Pre-treatment age was 11.3, treatment time 4.2 years and average follow-up age 31.2 Pre-treatment differences between extraction and non-extraction patients were addressed by segregating the sample into balanced sub-groups. "The extraction subgroup exhibited significantly more relapse of crowding and rotation than the non-extraction sample".  "However the amount of therapeutic increase of upper and lower inter-molar width was found to be a factor in mandibular incisor relapse, which occurred more often in cases with excessive (> 4.0mm) posterior expansion".  However these patients were not being taught to keep their mouths closed   Orthotropists might not think 4mm excessive and for averaged size patients I consider 40mm to be the minimum maxillary width to accommodate a tongue which is likely to require 7 to 10mm expansion. (F damage)

5.      Luppanapornlarp S, and Johnstone LE.  1993. The effects of premolar-extraction. A long-term comparison of outcomes in “clear cut extraction and non-extraction Class II patients”.  The Angle Orthodontist. 63: 257-270.  “Attempts were made to contact each of 2500 St Louis University Class II Edgewise (0.022mm) patients who completed treatment between1969 and 1980”. Unfortunately for various reasons only 57 of these were included.  They note “The present findings therefore fail to support the common, influential belief that premolar extraction frequently causes ‘dished in’ profiles, ‘distalised mandibles and ultimately craniomandibular dysfunction”. A negative result based on a two percent sample which was likely to have included a higher proportion of satisfied patients must be considered flawed.  (Facial damage).

6.      Melson B, Hansen K and Hagg U. 1999.  Overjet reduction and molar correction in fixed appliance treatment of class II division 1 malocclusions: Sagittal and vertical components.  American Journal of Orthodontics and Dentofacial Orthopedics 115:13-23.  Subjects 20 consecutive male non-extraction Begg technique.  Two were excluded for non-completion of treatment.  “The anterior lower facial height increased significantly more during this (treatment) period than during the control period”.  Conclusion “Vertically the net effects of treatment are to increase both the mandibular plane angle and the lower anterior facial height”. (F damage)

7.      Stellzig AS, Basdra EK, Kube C. and Komposch G. 1999  “Extraction Therapy in Patients with Class II/2 Malocclusion”. Journal of Orofacial Orthopedics. 60:39-52.  This paper appears to have had the objective of showing that second molar extraction is preferable to pre-molar extraction and found that “extraction of 60% of the lower third molars was considered necessary after pre-molar extractions”.  However the E-line measurements would suggest that both types of extraction treatment damage the facial aesthetics more than the non-extraction controls. (F damage)