Mechanism of Class II correction in prepubertal and postpubertal patients with Twin Force Bite Corrector

Abstract

Objective: To compare the dentoskeletal effects and treatment efficiency of the Twin Force Bite Corrector (TFBC) appliance in Class II correction of patients treated before or after the pubertal growth spurt. Materials and Methods: Forty-one normodivergent Class II patients treated with the TFBC appliance were divided into two groups based on their cervical vertebral maturation stage (CVMS). Group 1 (G1) consisted of 23 patients (mean age 12.44 6 1.59 years) where treatment was initiated before the pubertal growth spurt (CVMS I and II), while group 2 (G2) consisted of 18 patients (mean age 13.76 6 1.44 years) where treatment was started after the pubertal growth spurt (CVMS III to V). Dentoskeletal measurements were made on lateral cephalograms taken before (T1) and after orthodontic treatment (T2). Results: During treatment, G1 had significantly greater skeletal correction than G2, with more dentoalveolar effects being observed in G2 than G1. However, on comparing both groups at the end of treatment (T2) when growth is complete, no differences in the parameters measured were observed. Overall, treatment time was significantly longer for G1 (3.67 6 1.45 years) compared to G2 (2.75 6 1.07 years). Conclusions: There is no difference in overall dentoskeletal effects obtained at the end of treatment by the TFBC appliance in normodivergent prepubertal vs postpubertal patients. However, treatment efficiency based on treatment timing is significantly greater for the postpubertal group. (Angle Orthod. 2013;83:718-727.)

Evaluation of the Treatment Outcomes for Class II Malocclusion by Using PowerScope Appliance

“…Also upper incisor inclination to NA and upper incisor position relative to NA were significantly decreased. These results agreed with other studies on PowerScope (6,8) .Similar results were reported with TFBC (14)(15)(16) with AdvanSync (12,13) and with Eureka Spring (20) .…”

“…Similar results were reported with PowerScope in other studies (6,8,9) as well as with TFBC (14,16) . Nearly all studies on FFAs that reported its effect on soft tissues revealed the same (10,22) .…”

“…This effect is often observed with the use of fixed functional appliances, similar finding in other studies was reported after using PowerScope in treatment of Class II malocclusion (6,7) significant reduction in SNA was also reported with the use of Herbst appliance (10) as well as with Jasper Jumper (11) and after treatment with AdvanSync appliance (12,13) Regarding the mandible there was significant anterior displacement demonstrated by statistically significant increase in SNB (P<0.001), Similar finding was reported in other studies using PowerScope Class II corrector (6)(7)(8)(9) same results were demonstrated with TFBC (14)(15)(16) and also with Herbst appliance (5,10,22) and with mandibular protraction appliance (17) . However other studies demonstrated different results as with MARA (18) .…”

“…Similar results were obtained with TFBC (16) .On the other hand Chhibber et al reported that upper molars underwent mesial movement with TFBC treatment and explained that such finding might be attributed to the mechanics involved during finishing of treatment after removal of FFA or natural tendency of teeth to drift mesially (14) .…”

Long-term surgical versus functional Class II correction: A comparison of identical twins

“…6 The use of functional/FFAs to enhance mandibular growth has been questionable. 7 Class II correction with such devices is usually a combination of skeletal and dental changes, including restraining maxillary growth, mild mandibular growth, proclination of mandibular and retroclination of maxillary incisors often called ''side effects'' of using such appliances. 8 Orthognathic surgery, on the other hand, is aimed at correction of the underlying skeletal discrepancy without the ''side effects'' associated with FFAs.…”