Treatment effects of skeletally anchored Forsus FRD EZ and Herbst appliances: A retrospective clinical study

Abstract

Objective: To evaluate the skeletal, dentoalveolar, and soft tissue effects of the Forsus FRD appliance with miniplate anchorage inserted in the mandibular symphyses and to compare the findings with a well-matched control group treated with a Herbst appliance for the correction of a skeletal Class II malocclusion due to mandibular retrusion.

Materials and methods: The sample consisted of 32 Class II subjects divided into two groups. Group I consisted of 16 patients (10 females and 6 males; mean age, 13.20 ± 1.33 years) treated using the Forsus FRD EZ appliance with miniplate anchorage inserted in the mandibular symphyses. Group II consisted of 16 patients (9 females and 7 males; mean age, 13.56 ± 1.27 years) treated using the Herbst appliance. Seventeen linear and 10 angular measurements were performed to evaluate and compare the skeletal, dentoalveolar, and soft tissue effects of the appliances using paired and Student's t-tests.

Results: Both appliances were effective in correcting skeletal class II malocclusion and showed similar skeletal and soft tissue changes. The maxillary incisor was statistically significantly more retruded in the skeletally anchored Forsus FRD group (P < .01). The mandibular incisor was retruded in the skeletally anchored Forsus FRD group (-4.09° ± 5.12°), while it was protruded in the Herbst group (7.50° ± 3.98°) (P < .001).

Conclusion: Although both appliances were successful in correcting the skeletal Class II malocclusion, the skeletally anchored Forsus FRD EZ appliance did so without protruding the mandibular incisors.

Keywords: Class II malocclusion; Forsus FRD EZ; Herbst; Skeletal anchorage.

Figure 1.

Miniplates inserted in mandibular symphysis and application of the skeletally anchored Forsus FRD appliance.

Figure 2.

Application of the Herbst appliance.

Figure 3.

Reference planes used in the study.

Figure 4.

Angular measurements used in the study (°); (1) SNA, (2) SNB, (3) ANB, (4) Convexity, (5) SN-MP, (6) PP-MP, (7) U1-SN, (8) IMPA, (9) U1-L1, (10) Soft tissue convexity.

Figure 5.

Linear measurements used in the study (mm); (1) Co-A, (2) A-HRL, (3) A-VRL, (4) Co-Gn, (5) B-HRL, (6) B-VRL, (7) Pog-HRL, (8) Pog-VRL, (9) overjet, (10) overbite, (11) Ms-HRL, (12) Ls- HRL, (13) Ls- VRL, (14) Li- HRL, (15) Li- VRL, (16) Pog(s)-HRL, (17) Pog(s)-VRL.