Evaluating the efficiency of mandibular molar protraction using Herbst appliances versus temporary anchorage devices: a retrospective case-controlled study.

Mandibular second premolar agenesis is a common problem in orthodontics and is often treated in conjunction with maxillary counterbalancing extractions. However, in cases without maxillary crowding or dental protrusion, space closure may pose challenges leading to compromised occlusal results or patient profile. Multiple techniques have been described to treat these patients; nevertheless, there is a paucity of data comparing effectiveness of space closure utilizing various anchorage techniques. The goal of this study is to assess the effectiveness of the Herbst device during mandibular molar protraction and compare it to the use of temporary anchorage device (TADs) in patients with mandibular second premolar agenesis. This retrospective study included 33 patients with mandibular premolar agenesis treated without maxillary extractions. Of these patients, 21 were treated with protraction Herbst devices and 12 with TADs. Changes in molar and incisor positions, skeletal base positions and occlusal plane angulations were assessed on pretreatment (T0) and post-treatment (T1) lateral cephalograms. Scans/photographs at T0 and T1 were used to evaluate canine relationship changes representing anchorage control. Space closure and breakage/failure rates were also compared. Data was analyzed with paired and unpaired t-tests at the significance level of 0.05. Within the Herbst group, changes in mandibular central incisor uprighting and mandibular molar crown angulations were statistically significant. However, no significant differences were noted between the Herbst and TAD groups. Protraction rates as well as overall treatment times were comparable (0.77 mm/month vs. 0.55 mm/month and 3.02 years vs. 2.67 years, respectively). Canine relationships were maintained or improved toward a class I in 82.85% of the Herbst sample, compared to in 66.7% of the TAD sample. Emergency visits occurred in 80.1% of the Herbst group, with cementation failures or appliance breakages as the most common reasons. The Herbst device could be a viable modality in cases with missing mandibular premolars where maximum anterior anchorage is desired, or if patients/parents are resistant to TADs. Furthermore, they could be beneficial in skeletal class II patients with mandibular deficiency who also need molar protraction. However, the increased incidence of emergency visits must be considered when treatment is planned.

Taneja IZ ，Zhai G ，Kravitz ND ，Dischinger B ，Johnston M ，Kau CH ，Lamani E ... -  《Progress in Orthodontics》

Comparison of anchorage reinforcement with temporary anchorage devices or a Herbst appliance during lingual orthodontic protraction of mandibular molars without maxillary counterbalance extraction.

Metzner R ，Schwestka-Polly R ，Helms HJ ，Wiechmann D ... -  《Head & Face Medicine》

Quality of occlusal outcome following space closure in cases of lower second premolar aplasia using lingual orthodontic molar mesialization without maxillary counterbalancing extraction.

Klang E ，Beyling F ，Knösel M ，Wiechmann D ... -  《Head & Face Medicine》

Mandibular molar protraction: A comparison between fixed functional appliances and temporary anchorage devices.

This study aimed to compare the efficiency of temporary anchorage devices (TADs) and fixed functional appliances (FFAs) for mandibular molar protraction. Orthodontic records of 1050 consecutively treated patients with molar protraction were screened. Thirty-six records (22 females and 14 males; mean age, 17.4 years) were divided into two groups: TAD (21 subjects with 25 edentulous spaces) and FFA (15 subjects with 24 edentulous spaces). The primary outcome measure was the efficiency of protraction [magnitude and time required for protraction (rate) and anchor loss (AL)]. The secondary outcomes involved measuring the type of tooth movement (TOTM), external apical root resorption (EARR), alveolar bone height change (ABHC), alveolar bone width change (ABWC) and appliance failure. The rate of tooth movement was significantly higher for FFAs (0.83 ± 0.35 mm/month) versus TADs (0.49 ± 0.2 mm/month) (P = .005). Total treatment duration was less for FFAs (34.78 ± 8.1 months) versus TADs (47.72 ± 13.94 months) (P = .002). TOTM was similar for both (P = .909). EARR was 1.42 ± 1.38 mm for TAD and 1.25 ± 0.88 mm for FFA (P = .81). ABHC increased in the FFA group (1.01 ± 3.62 mm) and decreased for the TAD group (0.68 ± 1.66 mm). ABWC increased for both TAD (1.81 ± 1.73 mm) and FFA (1.75 ± 1.35 mm). The failure rate was 50% for FFAs and 33% for TADs. Both systems provided translation of lower molars with comparable anchorage control. However, FFAs were more efficient than TADs for lower molar protraction.

Alshehri A ，Abu Arqub S ，Betlej A ，Chhibber A ，Yadav S ，Upadhyay M ... -  《-》

Maxillary molar distalization or mandibular enhancement: a cephalometric comparison of comprehensive orthodontic treatment including the pendulum and the Herbst appliances.

Burkhardt DR ，McNamara JA Jr ，Baccetti T 《AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS》