Mandibular incisor inclination, tooth irregularity, and gingival recessions after Herbst therapy: a 32-year follow-up study.

INTRODUCTION

The aim of this study was to analyze the very long-term results after Herbst treatment with respect to changes in the mandibular incisor segment: incisor inclination, incisor alignment, and gingival status.

METHODS

Fourteen patients were derived from a sample of 22 consecutive patients with Class II Division 1 malocclusions treated with the banded Herbst appliance. Intraoral photographs, mandibular dental casts, and lateral head films were analyzed from before (T1, age 12.5 years) and after (T2, age 14 years) treatment, and at 6 years (T3, age 20 years) and 32 years (T4, age 46 years) after treatment.

RESULTS

At T1, incisor inclination in the 14 subjects was, on average, 100.1°. From T1 to T2, the incisors were proclined in 11 (79%) of the 14 patients, with an average value of 5.2°. Maximum proclinations of 10° were found in 2 subjects. From T2 to T4, tooth inclination recovered completely in 7 (63%) of the 11 patients. Incisor irregularity values were, on average, 3.4 mm at T1 and 3.0 mm at T2. These increased from T2 to T4 by 40% and had an average value of 5.0 mm at T4. Clinically insignificant labial gingival recessions on single front teeth were registered in 1 subject at T2 and in 8 subjects at T4. Gingival recessions were seen especially on bodily displaced incisors.

CONCLUSIONS

In Herbst patients followed for 32 years after therapy, proclined mandibular incisors generally rebounded. The increase in posttreatment incisor tooth irregularity was not thought to be related to incisor tooth inclination changes but more likely resulted from physiologic processes occurring throughout life. Minor gingival recessions (especially on bodily displaced and crowded canines and incisors) seen in a few patients, 32 years after treatment, seemed not to be related to the posttreatment tooth inclination changes.