Management of open bite that developed during treatment for internal derangement and osteoarthritis of the temporomandibular joint

Effects of vertical control on anatomic and aerodynamic characteristics of the oropharyngeal airway during premolar extraction treatment of Class II hyperdivergent nonsevere crowding malocclusion

INTRODUCTION

This study aimed to analyze the effects of premolar extraction treatment with vertical control on changes in the anatomy and aerodynamics of the oropharynx in Class II hyperdivergent malocclusion with nonsevere crowding.

METHODS

Thirty-nine patients with Class II hyperdivergent malocclusion were enrolled consecutively. All the participants underwent 4 premolar extractions. The high-pull J-hook and mini-implants were used to provide vertical control. Cone-beam computed tomography was performed before and after treatment. The participants were divided into a decreased lower vertical facial height group (n = 23) and an increased lower vertical facial height group (n = 16) on the basis of superimposition. The aerodynamic characteristics, including airway resistance (inspiration, R_in; expiration, R_ex) and maximum velocity (inspiration, Vmax_in; expiration, Vmax_ex) at inspiration and expiration, were calculated using computational fluid dynamics. Anatomic characteristics, including volume and cross-sectional area (CSA_min), were measured using the Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif).

RESULTS

After treatment, the median volume and CSA_min increased by 2357 mm³ and 43 mm², respectively, and median R_in and Vmax_ex decreased by 0.15 Pa/L/min and 0.24 m×s^-1, respectively, in decreased lower vertical facial height group. In contrast, the median CSA_min decreased by 9.5 mm² in the increased lower vertical facial height group. All the changes were statistically significant (all P <0.05). Significant differences in volume, CSA_min, R_in, and Vmax_ex were observed between the 2 groups.

CONCLUSIONS

Vertical control might improve the anatomic and aerodynamic characteristics of the oropharyngeal airway during premolar extraction treatment of Class II hyperdivergent malocclusion with nonsevere crowding.

Stability of vertical dimension following total arch intrusion

BACKGROUND

The purpose of this study is to evaluate stability of vertical dimension following total arch intrusion using miniscrews by measuring the change during treatment and relapse amount after more than one year of retention.

METHODS

Thirty patients (6 men, 24 women) were included in this study. Lateral cephalographs were taken with conventional radiography at the start of treatment (T0), after treatment (T1), and at least one year after treatment (T2). The evaluation was performed by measuring changes of selected parameters during treatment and the extent of relapse after more than one year.

RESULTS

During total arch intrusion treatment (T1-T0), anterior and posterior teeth intruded significantly. The mean vertical distance between the maxillary posterior teeth and palatal plane was reduced by 2.30 mm (P < 0.001). The mean vertical distance between the maxillary anterior teeth and palatal plane was reduced by 2.04 mm (P < 0.001). The anterior facial height was also reduced by 2.70 mm (P < 0.001). During retention period (T2-T1), the vertical distance between the maxillary anterior teeth and the palatal plane significantly increased by 0.92 mm (P < 0.001). The anterior facial height increased by 0.81 mm (P < 0.01).

CONCLUSIONS

Anterior facial height significantly decreases after treatment. During retention period, relapse of AFH and maxillary anterior teeth observed. There was no correlation between initial amount of AFH, mandibular plane angle, or SNPog and posttreatment AFH relapse. However, there was a significant correlation between the amount of intrusion of anterior and posterior teeth achieved by the treatment and the extent of relapse.

Fixed-functional appliance treatment combined with growth hormone therapy

The purpose of this study was to illustrate the effects of growth hormone (GH) therapy and fixed functional appliance treatment in a 13-year-old Class II malocclusion patient without GH deficiency. GH has been shown to effectively increase endochondral growth and induce a more prognathic skeletal pattern. Although a major concern in Class II retrognathic patients is chin deficiency, long-term studies have shown that the mandibular growth enhancement effects of functional appliances are clinically insignificant. This case report demonstrates that the mandible grew significantly during fixed functional appliance treatment combined with GH therapy, with stable results during 2 years 11 months of retention. More studies are needed to evaluate GH therapy as a supplement in Class II treatment.

Miniplate With a Bendable C-Tube Head Allows the Clinician to Alter Biomechanical Advantage in Extremely Complicated Anatomic Structure

BACKGROUNDS

This article reports C-tube miniplates as a practical temporary anchorage device choice to treat open bite patients with maxillary sinus pneumatization.

METHODS

The C-tube components are titanium anchor plates and monocortical screws that are basically similar to any other miniplate systems, but it has the unique characteristic of the tube head to be malleable. The manipulation of the head part is easy due to the composition of pure titanium. The I-shaped C-tube with 3 holes and T-shaped C-tube miniplates were placed above the apices of maxillary molars as an absolute anchorage system to intrude the posterior maxilla. The bending of the tube heads assisted in reduction of severe open bite patient with maxillary sinus pneumatization.

RESULTS

Sinus perforation during placement of skeletal anchorage system weakens stability of the anchorage and further cause complications. Placement of titanium C-tube miniplates allowed reliable skeletal anchorage and avoided maxillary sinus perforation in patients with extreme pneumatizations. Simple bending of C-tube miniplates ensured increased orthodontic intrusion force without having to replace them, and eliminated consequences such as perforation of maxillary sinus, sinusitis, soft tissue irritation, or infection.

CONCLUSIONS

Anatomic difficulties in the placement of temporary anchorage device can be easily managed by using the bendable C-tube miniplate. It can serve as a great alternative over miniscrews or regular miniplates with reduced risk of sinus perforation and ability to bend the head portion to control orthodontic vectors and forces.

Total intrusion and distalization of the maxillary arch to improve smile esthetics

This case report illustrates the successful treatment of a patient with skeletal Class II malocclusion and an unesthetic smile involving excessive gingival display and large buccal corridors. By applying dual buccal interradicular miniscrews, total intrusion of the maxillary dentition along with distalization was induced to improve both the occlusion and smile esthetics. In addition to the conventional cephalometric superimposition, three-dimensional superimposition was performed and evaluated to validate the treatment outcome.