Dentoskeletal effects of Twin Block appliance in patients with Class II malocclusion

Abstract

Background and aim. Class II malocclusions are most commonly seen in orthodontic practice and in the recent times Twin Block appliance has been the most popular and widely used among removable functional appliances for the correction of Class II malocclusion in growing patients. The aim of this retrospective study was to evaluate the dentoskeletal effects produced by the Twin Block appliance for the correction of Class II division 1 malocclusion with retrognathic mandible.
 Methods. Pre-treatment (T1) and post-treatment (T2) lateral cephalograms of 30 patients treated with Twin Block appliance (mean age = 10.8 ± 1.2 years) for the correction of class II division 1 malocclusion were compared with the 30 untreated class II control patients (mean age 11.2 ± 0.8 years) who did not undergo any treatment during this period. Both the groups were evaluated for the dentoskeletal changes using 24 angular and linear cephalometric measurements. The differences between the pre and post-treatment were calculated using a paired t-test.
 Results. The cephalometric analysis revealed that the Twin Block appliance stimulated mandibular growth and statistically significant differences were found between the two groups. Twin Block patients showed a statistically very high significant (p<0.001) increase in mandibular length (6.02 mm) compared with the control group (0.3 mm). ‘Headgear effect’ on the maxilla, increase in lower anterior facial height, significant reduction of overjet, overbite and Class I molar relationship was achieved in the Twin Block group. However, no significant changes appeared in the control group.
 Conclusion: The results of the present study conclude that the Twin Block appliance is effective in the treatment of Class II malocclusion and this is due to a combination of skeletal and dentoalveolar changes in both the arches.

The Effectiveness of Using Twin Block Functional Appliances and Activators in Class II Malocclusion

“…The Twin Block group experienced a "Headgear effect" resulting in a slight inhibition of sustained maxillary growth as evidenced by the decrease seen in the SNA angle (-0.7°) compared to the small increase seen in the SNA angle in the control subjects. (34) In the Twin Block group, the maxillary incisors retroclined, extruded, and tipped distally, while the mandibular incisors were proclined, intrusive, and labial tipped. The maxillary molars were distalized (1 mm) and extruded, on the other hand, the mandibular molars moved mesially (4.5 mm) and extruded whereas in the control group the maxillary molars were distalized (0.3 mm), and the lower molars moved mesially.…”

“…According to Clark, the twin block appliance is the most widely used among other types of functional appliance. (15)(16)(17) Twin block is often used in patients who are in growth period. The design that is separated into two parts, the top and bottom on this appliance provides convenience in speaking and chewing.…”

“…The design that is separated into two parts, the top and bottom on this appliance provides convenience in speaking and chewing. (16,18) A clinical trial has shown that class II malocclusion can be corrected with an activator device. It has been reported that maxillary growth can be limited by the use of an activator.…”

Comparison of Twin Block appliance and Herbst appliance in the treatment of Class II malocclusion among children: a meta-analysis

“…A previous study reported that treatment with the Herbst appliance stimulates growth in the condylar head and anterior remodeling of the glenoid fossa, leading to an enhanced maxilla-mandibular relationship in patients with growing skeletal Class II issues [ 9 ]. The Twin Block is the most favored and extensively utilized removable functional appliance for correcting Class II malocclusion in patients who are still growing [ 11 , 12 ]. A retrospective analysis indicated the effectiveness of the Twin Block appliance in treating Class II malocclusion, attributable to a mix of skeletal and dentoalveolar alterations in both dental arches [ 11 ].…”

Assessment of the condylar response of two differently anchored fixed functional appliances in class II malocclusion in young adult orthodontic patients: A randomized clinical trial

“…In patients with skeletal class II malocclusions, the mandible is typically too small and/or too retruded; hence, the goal of orthodontic and orthopedic treatment should be to move the jaw forward and stimulate the condyle growth and the glenoid fossa remodeling. [ 5 6 7 8 ]…”