Growth Treatment Response Vector (GTRV) Analysis in Class III Patients


  • Mohammad Said Youssef
  • Şirin Nevzatoğlu
  • Ahu Acar

Received Date: 02.08.2012 Accepted Date: 24.10.2012 Turk J Orthod 2012;25(3):214-223


The objective of the present study was to assess the posttreatment maxillary and mandibular growth in a group of Class III patients treated with facemask therapy, using the Growth Treatment Response Vector (GTRV) analysis, in an effort to predict excessive mandibular growth, and future surgical treatment need.

Subjects and Method:

Lateral cephalometric radiographs of 13 patients, (7 males and 6 females) were obtained from the archive of Marmara University, Faculty of Dentistry, Departament of Orthodontics. The mean age of the male and female patients at the beginning of the facemask treatment was found to be 12.46 and 11.4 years respectively. Two cephalometric radiographs taken from each patient comprised the material of the study; one posttreatment radiograph taken immediately after maxillary protraction with facemask and another radiograph taken after 2 to 4 years of follow-up period. In order to predict excessive mandibular growth that occurred after facemask treatment and to detect the possible need for future orthognathic surgery, the GTRV analysis was performed. After 6 years of performing GTRV analysis patients were recalled and rechecked.


It was found that only in 2 out of 13 cases, the GTRV ratio was below 0.33, indicating a definite need for surgery. Three cases had GTRV values below 0.38 but higher than or equal to 0.33, indicating possibility of future need of surgery. Reevaluation of the patients six years after performing the GTRV analysis showed that the treatments of 11 patients were already completed successfully. It was detected that only 2 patients had indications for orthognathic surgery. While one patient underwent surgery and the other one refused to have it and received compensation treatment with a compromised outcome.


Facemask is one of the most popular appliances, which is used in the early treatment of Class III patients with maxillary deficiency. A follow up lateral cephalogram can be taken 2–4 years after completion of the protraction with the facemask and can be used in the calculation of the GTRV ratio which predicts the future mandibular growth and gives a clear idea to the clinician, patient and family about possible future need of surgery.

Keywords: GTRV, Class III malocclusion, Facemask, Growth prediction.