Class II treatment by extraction of maxillary first molars or Herbst appliance: dentoskeletal and soft tissue effects in comparison.

AIM: To compare dentoskeletal and soft tissue treatment effects of two alternative Class II division 1 treatment modalities (maxillary first permanent molar extraction versus Herbst appliance). METHODS: One-hundred-fifty-four Class II division 1 patients that had either been treated with extractions of the upper first molars and a lightwire multibracket (MB) appliance (n = 79; 38 girls, 41 boys) or non-extraction by means of a Herbst-MB appliance (n = 75; 35 girls, 40 boys). The groups were matched on age and sex. The average age at the start of treatment was 12.7 years for the extraction and for 13.0 years for the Herbst group. Pretreatment (T1) and posttreatment (T2) lateral cephalograms were retrospectively analyzed using a standard cephalometric analysis and the sagittal occlusal analysis according to Pancherz. RESULTS: The SNA decrease was 1.10° (p = 0.001) more pronounced in the extraction group, the SNB angle increased 1.49° more in the Herbst group (p = 0.000). In the extraction group, a decrease in SNB angle (0.49°) was observed. The soft tissue profile convexity (N-Sn-Pog) decreased in both groups, which was 0.78° more (n. s.) pronounced in the Herbst group. The nasolabial angle increased significantly more (+ 2.33°, p = 0.025) in the extraction group. The mechanism of overjet correction in the extraction group was predominantly dental (65% dental and 35% skeletal changes), while in the Herbst group it was predominantly skeletal (58% skeletal and 42% dental changes) in origin. CONCLUSION: Both treatment methods were successful and led to a correction of the Class II division 1 malocclusion. Whereas for upper first molar extraction treatment more dental and maxillary effects can be expected, in case of Herbst treatment skeletal and mandibular effects prevail.

Overjet correction and space closure mechanisms for Class II treatment by extracting the maxillary first molars.

OBJECTIVE: To analyze the mechanism of overjet correction and space closure when treating Class II Division 1 patients by extracting the maxillary first molars. PATIENTS AND METHODS: A total of 100 prospective, consecutively treated Class II Division 1 patients (45 female, 55 male; 10.5-17.2 years old). Standardized lateral cephalograms prior to and after treatment were evaluated via a modified sagittal occlusion analysis (SO analysis). RESULTS: The mean degree of overjet correction was 5.2 mm (95% CI = 4.8-5.6 mm) and was on average achieved by means of 1.7 mm skeletal and 3.5 mm dental changes. The relationship between the premolars improved by 4.8 mm toward a Class I relationship, facilitated by 1.7 mm skeletal and 3.1 mm dental changes. The 11.3 mm space closure in the maxillary first-molar extraction area resulted from distalization of the second premolars (1.4 mm) and a mesialization of the second molars (9.9 mm). CONCLUSIONS: Overjet correction was essentially achieved by a retrusion of the upper incisors, as well as by ventral growth of the lower jaw and protrusion of the lower incisors. Space closure was only partly achieved by distalization of the premolars.