The effects of surgically assisted rapid maxillary expansion (SARME) on the dental show and chin projection

J Craniomaxillofac Surg. 2017 Nov;45(11):1835-1841. doi: 10.1016/j.jcms.2017.08.023. Epub 2017 Aug 31.


Objective: To quantify the postoperative changes of the dental show and chin projection following SARME using 3D CBCT imaging.

Material and methods: 78 patients with transversal maxillary hypoplasia and mandibular hypoplasia who underwent SARME were enrolled into the study. A cone beam computed tomography (CBCT) scan was acquired preoperatively and at least 1 year postoperatively. 3D postoperative changes in the dental show and pogonion position were measured based on soft tissue and hard tissue landmarks.

Results: 68 patients (87%) exhibited a postoperative increase in the dental show. The dental show was increased by a mean of 2.2 ± 2.0 mm (p < 0.01). The mean horizontal and vertical displacement of the chin (pogonion) following SARME was 1.6 ± 2.5 mm posteriorly and 1.6 ± 2.0 mm inferiorly (p < 0.01). An inferior displacement of the maxilla and maxillary tooth as well as a consequent clockwise pitch of the mandible seemed to play a role in inducing these postoperative changes.

Conclusion: An increase in dental show and a posterior and inferior displacement of the chin should be considered prior to SARME to prevent undesirable postoperative changes of the facial esthetics.

Keywords: 3D; CBCT; Chin; Dental show; Maxillary expansion; SARME.

MeSH terms

  • Adolescent
  • Adult
  • Cephalometry
  • Chin / anatomy & histology*
  • Chin / diagnostic imaging
  • Cone-Beam Computed Tomography*
  • Esthetics, Dental
  • Female
  • Humans
  • Imaging, Three-Dimensional
  • Male
  • Mandible / abnormalities
  • Mandible / diagnostic imaging*
  • Mandible / surgery*
  • Maxilla / abnormalities
  • Maxilla / diagnostic imaging*
  • Maxilla / surgery*
  • Middle Aged
  • Palatal Expansion Technique*
  • Retrospective Studies
  • Tooth
  • Young Adult