Treatment in Borderline Class III Malocclusion: Orthodontic Camouflage (Extraction) Versus Orthognathic Surgery

Abstract

Aims: To investigate the differences in morphological characteristics of borderline class III patients who had undergone camouflage orthodontic treatment or orthognathic surgery, and to compare the treatment effects between these two modalities.

Materials and methods: Cephalograms of 25 patients (13 orthodontic, 12 surgical) with class III malocclusion were analyzed. All had a pretreatment ANB angle greater than -5 masculine.

Results: Using discriminant analysis, only Holdaway angle was selected to differentiate patients in the pretreatment stage. Seventy-two per cent patients were correctly classified. In the orthodontic group, reverse overjet was corrected by retraction of the lower incisors and downward and backward rotation of the mandible. The surgical group was corrected by setback of the lower anterior dentoalveolus and uprighting of the lower incisors. No difference was found in posttreatment soft tissue measurements between the two groups.

Conclusions: Twelve degree for the Holdaway angle can be a guideline in determining the treatment modalities for borderline class III patients, but the preferences of operators and patients are also important. (2) Both therapeutic options should highlight changes in the lower dentoalveolus and lower incisors. (3) Both treatment modalities can achieve satisfactory improvements to the people.

Keywords: Class III malocclusion; camouflage; orthognathic surgery.

Fig. (1)

Extra-oral, intra-oral and cephalograms of one orthodontic sample before and after treatment

Fig. (2)

Extra-oral, intra-oral and cephalograms of one surgical sample before and after treatment

Fig. (3)

Landmarks used in this study: 1, soft-tissue nasion; 2, labrale superius; 3, labrale inferius; 4, soft-tissue pogonion; 5, sella; 6, nasion; 7, orbitale; 8, posterior nasal spine; 9, anterior nasal spine; 10, point A; 11, upper incisor apex; 12, incision superius; 13, upper first premolar tip; 14, upper molar mesial cusp tip; 15, lower molar mesial cusp tip; 16, lower first premolar tip, 17, incision inferius 18, lower incisor apex; 19, point B; 20, pogonion; 21, gnathion; 22, menton 23, lower gonion; 24, gonion; 25, posterior gonion; 26, arti-culare; 27, basion; 28, porion; 29, sphenoethmoidal point; 30, ptery-gomaxillare.

Fig. (4)

Superimposition of averaged pretreatment tracings of orthodontic and surgical groups along S-N at sella. Orthodontic group (dashed line); Surgical group (solid line).

Fig. (5)

Superimposition of averaged pretreatment and posttreatment tracings within orthodontic group along S-N at sella. Pretreatment (black line); Posttreatment (red line).

Fig. (6)

Lower incisor position change. Mandibular tracings super-imposed on anterior contour, internal cortical surface of the sym-physis and mandibular canal. Pretreatment (black line), posttreat-ment (red line) m   The mesiobuccal cusp tip of the mandibular permanent first molar it   The incisal tip of the most prominent mandibular central incisor ii   The incisal apex of the most prominent mandibular central incisor OL   Occlusal line, a line through m and the buccal cusp tip of the mandibular first premolar OLP   Occlusal line perpendiculare, a line perpendicular to OL through the most anterior point of the bony chin symphysis

Fig. (7)

Superimposition of averaged pretreatment and posttreatment tracings within surgical group along S-N at sella. Pretreatment (black line); Posttreatment (red line).

Fig. (8)

Superimposition of averaged posttreatment tracings of orthodontic and surgical groups along S-N at sella. Orthodontic group (dashed line); Surgical group (solid line)