vendex and Prognathism

An 8-year-old girl with a skeletal Class III malocclusion was treated in 2 phases. Maxillary expansion and protraction were carried out as the early intervention. However, her maxillary hypoplasia and mandibular hyperplasia deteriorated with age. The phase 2 comprehensive treatment began with proper mechanics when she was 12 years old with growth potential. In the maxillary arch, an auxiliary rectangular wire was used with a round main wire and an opening spring to create space for the impacted teeth and to bodily move the anterior teeth forward. Decompensation of mandibular incisors and correction of the Class III malocclusion were achieved by short Class III elastics with light forces and a gentle interaction between the rectangular wires and the lingual root-torque slots. The phase 2 active treatment period was 4 years 8 months. The 2-year follow-up indicated that our treatment results were quite stable.

Topics: Cephalometry; Child; Female; Follow-Up Studies; Humans; Incisor; Malocclusion, Angle Class III; Mandible; Maxilla; Orthodontic Wires; Orthodontics, Interceptive; Palatal Expansion Technique; Patient Care Planning; Prognathism; Retrognathia; Tooth Movement Techniques; Tooth Root; Tooth, Impacted; Torque

Surgical simulation should reflect the 3D movement of dentition and the resultant movement of the osteotomized segments, which can influence surgical outcome. The present study was aimed at developing a new simulation system that enables virtual osteotomy of a given surgical situation and evaluation of the bony interference between the osteotomized segments of the mandible.. The data of 3D computer tomography (CT) for maxillomandibular dental casts were integrated into the standard coordinates of a 3D cephalogram. To evaluate the accuracy of the system, measurement errors of the 3D CT virtual model from a dry skull were compared with the computer simulation system and a contact-type 3D digitizer. To examine the clinical accessibility, 15 mandibular prognathism patients with mild to severe asymmetry were evaluated with the simulation program.. The average error of measurement in all directions was 1.31 mm. It was possible to simulate various osteotomy procedures by conversion of the 3D coordinates of the dental cast and CT data into the standard coordinate system of a 3D cephalogram. Using this simulation system, it was possible to prevent condylar torque or segment malpositioning by removing the bony interference visualized by a 3D virtual model.. A new system, which enables the precise visualization of osteotomized segments and calculation of bony interference, was proposed in the present study. This new system provides an acceptable precision of treatment planning of orthognathic surgery, especially for facial asymmetry.

Topics: Bone Plates; Bone Wires; Cephalometry; Computer Simulation; Facial Asymmetry; Female; Follow-Up Studies; Forecasting; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Mandible; Mandibular Condyle; Models, Dental; Orthognathic Surgical Procedures; Osteotomy, Sagittal Split Ramus; Patient Care Planning; Prognathism; Reproducibility of Results; Rotation; Tomography, X-Ray Computed; Torque; User-Computer Interface; Young Adult

To compare the influence of occlusal versus craniofacial characteristics on the functionality of the stomatognathic apparatus.. Two groups of subjects were selected: 27 patients (13 women and 14 men), 18 to 42 years old, all candidates for orthognathic surgery, 7 with prognathic syndrome and 20 with progenic syndrome; and 26 healthy young adults (13 women and 13 men) of corresponding age (control group). To verify the neuromuscular equilibrium induced by occlusion, the electromyographic activities of both right and left masseter and anterior temporal muscles were recorded and analyzed, calculating the percentage overlapping coefficient (an index of the symmetric distribution of the muscular activity determined by the occlusion) and TORS (index of the presence of mandibular torque). Data were compared with Student t-test for independent samples.. Between the 2 groups of patients, no statistically significant differences were found, whereas the statistical analysis showed differences between patients and control subjects (P < 0.05): overall, the control subjects had a better neuromuscular stability than the patients who were candidates for orthognathic surgery.. The electromyographic evaluations revealed that there was a neuromuscular imbalance determined by an occlusal instability in the patients candidates for orthognathic surgery, thus indicating that occlusion plays a more important role than any possible mechanical disadvantages due to altered craniofacial morphology.

Topics: Adolescent; Adult; Case-Control Studies; Electromyography; Female; Humans; Male; Malocclusion; Masticatory Muscles; Prognathism; Torque

The Bidimensional technique is an edgewise technique in which 2 different sized vertically slotted brackets are used. On the central and lateral incisors, .018" x .022" brackets are placed on the central and lateral incisors and .022" x .028" brackets are placed on the canines, molars and premolars. The maxillary incisor brackets are programmed. All movements, including bodily retraction of the maxillary incisors are produced by sliding mechanincs. When retracting maxillary incisors, an .018" x. 022" wire which fills the vertical portion of the brackets, providing torque control, is inserted and 300 gm intra arch forces are placed for incisor retraction. In the buccal segments, the .018" x .022" wire is undersized relative to the canine, premolar and molar brackets and can readily slide through the brackets and tubes. The method is described and illustrated with one case report of the extraction treatment of a patient with Class I bimaxillary protrusion.

Topics: Adolescent; Bicuspid; Dental Alloys; Dental Stress Analysis; Humans; Male; Malocclusion, Angle Class I; Mechanics; Nickel; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Orthodontics, Corrective; Prognathism; Titanium; Tooth Extraction; Torque

This study was performed to compare the condylar position and angulation on 3-dimensional (3D) views between greater setback side (GSS) and lesser setback side (LSS) after asymmetric mandibular setback (AMS) using computed tomography.. The sample consisted of 12 Korean skeletal class III malocclusion patients with mandibular prognathism and facial asymmetry, who underwent sagittal split ramus osteotomy (SSRO) with rigid fixation. Tomographs were taken 1 month before (T1) and 6 months after surgery (T2). Position and angulation of the condyles were measured.. At T1 stage, the condylar head in GSS showed more forward inclination on the sagittal view (P < .05) than that of LSS. Although there were significant inward and backward rotations of the condylar head in GSS (P < .01) and significant backward rotation in LSS at T2 stage (P < .05), 3D positions of the condyle in GSS and LSS were not changed after AMS.. SSRO might be effective to stabilize the condylar position for AMS.

Topics: Adolescent; Adult; Cephalometry; Facial Asymmetry; Female; Humans; Imaging, Three-Dimensional; Male; Malocclusion, Angle Class III; Mandible; Mandibular Condyle; Oral Surgical Procedures; Osteotomy; Prognathism; Radiography, Dental; Secondary Prevention; Tomography, X-Ray Computed; Torque

This retrospective study was designed to assess skeletal stability after the correction of mandibular prognathism by sagittal split osteotomy (SSO) and intraoral vertical subsigmoid osteotomy (VSO). We used lateral cephalographs of 31 patients taken before, immediately after, and at least one year after the operation. We recorded euclidean distance matrix analysis, linear and angular measurements, and x and y co-ordinates of cephalometric landmarks for each cephalograph. There were no significant differences in extent of the mandibular retrognathia or magnitude of change between the two groups. The main significant changes in both groups were reduction of the total mandibular length, and posterior shifting in the mandible. One year after the operation the main change was the mean forward relapse of 2.5 mm in the SSO group and the mean posterior relapse of 0.5 mm in the VSO group. The difference in skeletal stability between the groups was significant (P< 0.05), and we conclude that VSO is the more effective technique for correcting mandibular prognathism.

Topics: Adolescent; Adult; Cephalometry; Female; Humans; Male; Malocclusion, Angle Class III; Mandible; Mandibular Condyle; Oral Surgical Procedures; Osteotomy; Prognathism; Recurrence; Reproducibility of Results; Retrospective Studies; Torque; Treatment Outcome