Class II correction improves nocturnal breathing in adolescents

Abstract

Objective: To examine modifications in sleep pattern and in craniofacial morphology of adolescents with mandibular retrognathism. Materials and Methods: Sixteen subjects at maximum pubertal growth (12.6 years [611.5 months]) were selected and treated for 12 months with maxillary expansion and mandibular advancement with a Herbst appliance. Cephalometric radiography and magnetic resonance imaging were obtained prior to and after treatment and were compared using the paired Student's t-test or the nonparametric Wilcoxon rank-sum test. Four polysomnographic recordings were obtained with pressurized nasal cannulae and were analyzed by analysis of variance. Results: The length of the mandible was increased, while the antero-posterior position of the maxilla remained stable. The posterior airway space was increased, the length of the tongue was preserved, and the hyoid bone was moved to a more anterior position. After Herbst treatment, sleep efficiency, sleep latency, rapid eye movement (REM) sleep latency, and percentage of REM sleep remained stable. We did observe a reduction (P , .05) in the relative proportions of stage 1 and stage 3-4 (from 4.30 6 1.99 to 2.61 6 1.83 for stage 1 and from 25.78 6 7.00 to 19.17 6 7.58 for stages 3-4) as well as an increase (P , .01) in the percentage of stage 2 after treatment (49.03 6 6.25 to 56.90 6 6.22). There was a reduction (P , .05) in the number of respiratory effortrelated arousals (7.06 6 5.37 to 1.31 6 1.45 per hour of sleep) due to an increase (P , .01) in airway volume. Conclusions: In the short term, the increase in airway space improved nocturnal breathing associated with the correction of mandibular retrognathism. (Angle Orthod. 2011;81:222-228.)

Effectiveness of twin-block and Mandibular Protraction Appliance-IV in the improvement of pharyngeal airway passage dimensions in Class II malocclusion subjects with a retrognathic mandible

“…Similar to our observation, Ozbek et al 11 also noted a 2.08 6 0.59 mm increase in the DOP following Class II treatment with the Harvold activator. Schutz et al, 17 however, reported 3.2 mm improvement of the posterior airway space following maxillary expansion and Herbst therapy in Class II subjects. They explained that Herbst appliance therapy displaced the mandible and hyoid bone forward and caused anterior traction of the tongue and increased the posterior airway space.…”

“…They explained that Herbst appliance therapy displaced the mandible and hyoid bone forward and caused anterior traction of the tongue and increased the posterior airway space. 17 However, Kinzinger et al 16 recommended that treatment of Class II malocclusion by functional mandibular advancer and Herbst appliance was ineffective in preventing breathing problems in patients who were at risk. The DHP was marginally improved in our untreated Class II subjects and in those subjects in whom the Class II malocclusion was corrected by MPA-IV, but it was significantly improved in twin-block subjects.…”

“…9,10 Although there are numerous studies those have evaluated the nature of Class II correction by various functional appliances in growing skeletal Class II children, there are only a few studies that mention the PAP dimension changes following functional appliance treatment. Studies have been conducted to evaluate the effect of the Harvold activator, 11 an activator with high-pull headgear, 12 cervical headgear, 6 the Farmand appliance, 13 the modified bionator, 14 the Klammt appliance, 15 the Herbst appliance, 16 and rapid maxillary expansion with Herbst appliance therapy 17 on the PAP in Class II patients. However, to our knowledge there is no study in the literature mentioning the effect of the most commonly used functional appliance, that is, the twinblock appliance, in the improvement of PAP dimension among subjects with Class II malocclusion.…”

Effects of Functional Appliance Therapy on the Depth of the Pharyngeal Airways: Activator vs. Forsus

“…Eventually, the main objective of our study, i.e., subsequent effects of these appliances on the dimensions of pharyngeal airways, will be addressed. Having reviewed the literature, there are very few published studies [4,[10][11][12][13][14] that have investigated the effect of functional appliances on the dimensions of awake pharyngeal airways. Of these studies, four have included either headgear [4,10,12] or maxillary expansion [11] appliances in combination with functional appliances, and the other two studies have used only removable [13] The sample was then divided into two groups.…”

“…Having reviewed the literature, there are very few published studies [4,[10][11][12][13][14] that have investigated the effect of functional appliances on the dimensions of awake pharyngeal airways. Of these studies, four have included either headgear [4,10,12] or maxillary expansion [11] appliances in combination with functional appliances, and the other two studies have used only removable [13] The sample was then divided into two groups. The first group consisted of the subjects who were treated with removable functional appliances (Activator type), and the second group consisted of those who were treated with fixed functional appliances, Forsus Fatigue Resistant Device (FRD) (3M Unitek Corp, Monrovia, Calif).The sex and age distribution of the treatment groups are shown in Table 1.…”