Ilken Kocadereli

Use of three-dimensional medical modeling methods for precise planning of orthognathic surgery.

Stereolithographic (medical rapid prototyping) biomodeling allows three-dimensional computed tomography to be used to generate solid plastic replicas of anatomic structures. Reports in the literature suggest that such biomodels may have a use in maxillofacial surgery, craniofacial surgery, orthopedics, neurosurgery, otology, vascular, and nasal research. A prospective trial to assess the usefulness of biomodeling in orthognathic surgery has been performed. In 12 patients with mandibular prognathism and/or maxillary retrusion, in addition to routine preoperative cephalometric analysis, preoperative high-resolution (cutting slice thickness of 1 mm) three-dimensional computed tomography scan of the patients was obtained. Raw data obtained from computed tomography scanning was processed with a Mimics 9.22 Software (Materialises Interactive Medical Image Control System, Belgium). Fabrication of three-dimensional medical models was obtained through a process called powder depositional modeling by use of a Spectrum Z 510 3D Color Printer (Z Corporation, Burlington, MA). Alveolar arches of the maxilla and mandibula of the models were replaced with orthodontic dental cast models. Temporomandibular joints of the models were fixed with Kirschner wire. Maxillary and mandibular bony segments were mobilized according to preoperative orthodontic planning done by analysis of cephalometric plain radiographs. The relation between proximal and distal mandibular segments after bilateral sagittal split osteotomies were evaluated on models preoperatively. The same surgeon had a role in both model cutting preoperatively and as an instructor preoperatively. The same bony relation was observed both in preoperative modelsand in the perioperative surgical field in all patients. Condylar malpositioning was not observed in any of the patients. Studying preoperative planned movements of osteotomized bone segments and observing relations of osteotomized segments of mandibula and maxilla in orthognathic surgery increased the intraoperative accuracy. Limitations of this technology were manufacturing time and cost.

Lower Incisor Retraction with a Modified Corticotomy

This case report demonstrates the orthodontic treatment facilitated with a new conservative corticotomy technique to shorten the treatment time during lower incisor retraction. The patient was a 22-year-old woman with protrusive profile, severe anterior crowding, an anterior crossbite, and Class III dental relationship. Orthodontic treatment consisted of the extraction of four first premolars with maximum anchorage. A modified corticotomy technique, in which the lingual vertical and subapical horizontal cuts were eliminated, was combined with orthodontic therapy for the retraction of the lower anterior teeth. Corticotomy-facilitated orthodontics dramatically reduced the treatment time without any adverse effects on the periodontium and the vitality of the teeth. The main advantages of this modified corticotomy technique were the elimination of the lingual cuts and flap, the reduction of surgery time, and minimum discomfort to the patient. At the end of active orthodontic therapy, balanced occlusion and facial esthetics were achieved.

The effects of first premolar extractions on third molar angulations.

The purpose of this study was to determine the relationship between the inclinations of second and third molars during a two- to 2.5-year period in patients treated orthodontically both with and without premolar extractions. Records of 37 first premolar extraction patients and 33 nonextraction patients were examined. The pretreatment and posttreatment panoramic radiographs were analyzed. The angles were measured between the long axis of the third molar and the occlusal plane and between the long axis of the third molar and the long axis of the second molar. Changes in third molar angulations from pretreatment to posttreatment for two groups were compared by Mann-Whitney U-test. Statistical analysis revealed that mandibular third molars showed an improvement in angulation relative to the occlusal plane in the first premolar extraction group.

Effects of facemask treatment anchored with miniplates after alternate rapid maxillary expansions and constrictions; a pilot study.

OBJECTIVE To describe the dentoskeletal and soft tissue effects of facemask treatment anchored with miniplates after alternate rapid maxillary expansions and constrictions (Alt-RAMEC) in maxillary retrusion patients. MATERIALS AND METHODS The sample consisted of 15 patients with a mean skeletal age of 11.6 ± 1.59 years undergoing 8 weeks of Alt-RAMEC followed by maxillary protraction. Three hundred fifty to 400 g of force per side was applied to the facemask from the titanium miniplates inserted on the lateral nasal wall of the maxilla. Total treatment time was 9.9 ± 2.63 months. Treatment changes were evaluated cephalometrically and analyzed by means of the dependent t-test and the Wilcoxon signed rank test. RESULTS The miniplates withstood the orthopedic forces exerted during the treatment. Cephalometric findings showed that the maxilla moved forward by 2 mm, with an 0.8° counterclockwise rotation and without maxillary incisor movement. The mandible moved slightly in a downward and backward direction (1.2°). The inclinations of the mandibular incisors decreased significantly (2°). Statistically significant increases were observed in the vertical dimension (1°-1.3°). Soft tissue changes were more marked in the upper lip and soft tissue pogonion than in the lower lip. CONCLUSIONS This treatment approach can offer an advantage for correcting mild/moderate maxillary retrusion in Class III patients.

Arch width changes in extraction and nonextraction treatment in class I patients.

The aim of this retrospective study was to examine the dental arch width changes of extraction and nonextraction treatment in Class I patients. The study was performed on pretreatment and posttreatment dental casts of 60 patients (30 extraction and 30 nonextraction). The mean ages were 14.3 +/- 2.02 years for the extraction group and 14.1 +/- 2.9 years for the nonextraction group. The maxillary and mandibular crowding was -6.7 +/- 3.1 and -6.3 +/- 2.8 mm for the extraction group and -4.5 +/- 3.6 and -2.1 +/- 3.5 mm for the nonextraction group, respectively. The intercanine and intermolar arch width measurements were measured using a digital caliper. Paired samples t-test was used to evaluate the treatment changes within each group. To compare the changes between groups, independent samples t-test was performed. At the start of treatment, the maxillary and the mandibular intercanine and intermolar widths of both groups did not differ statistically. At the end of treatment, maxillary and mandibular intercanine widths of both groups increased significantly. The mandibular intermolar width decreased significantly for the extraction group and the maxillary intermolar width increased significantly for the nonextraction group. The decrease in maxillary intermolar width for the extraction group and the increase in mandibular intermolar width for the nonextraction group were not significantly different. No differences were observed between the groups in maxillary and mandibular intercanine widths. Maxillary and mandibular intermolar width indicated a significantly larger value in the nonextraction group than that in the extraction group.

Skeletal and Dental Stability After Maxillary Distraction With a Rigid External Device in Adult Cleft Lip and Palate Patients

PURPOSE To evaluate skeletal and dental stability in adult cleft lip and palate patients treated with a rigid external distraction system at the end of distraction and during the postdistraction period. PATIENTS AND METHODS Lateral cephalograms of 7 patients were obtained before distraction, at the end of distraction, and during the postdistraction period. The mean age before distraction was 21.56 +/- 4.73 years. The mean follow-up was 37.3 +/- 12.4 months. RESULTS The assessment of findings showed that skeletal maxillary sagittal movement was achieved in a superoanterior direction. The maxillary depth angle and effective maxillary length increased significantly (2 degrees and 9 mm, respectively) after distraction, whereas the palatal plane angle increased by 8 degrees , resulting in an anterior movement of the maxilla with a counterclockwise rotation. The lower facial height showed no significant changes after distraction. The sagittal movement of the upper incisors and the angulation of the upper first molars increased significantly (4.5 mm and 5.5 degrees , respectively). During the postdistraction period, the maxilla showed a slight relapse (22%). The effective maxillary length decreased by 2 mm. The palatal plane angle almost returned to its original position, showing 7 degrees of clockwise rotation. The lower facial height remained stable. The upper incisors moved anteriorly and the upper first molars showed a significant mesioangular change during follow-up. CONCLUSIONS After distraction, significant maxillary advancement was achieved with a counterclockwise rotation. The upper incisors moved labially, and the upper first molars angulated mesially. After 3 years, a 22% relapse rate was seen in the maxilla. The counterclockwise rotation of the maxilla was returned to its original position. The upper incisors moved more anteriorly.

Tridimensional evaluation of maxillary and mandibular movements in orthognathic surgery.

For better evaluation of long-term results of orthognathic surgery, movements of osteotomized maxillary and mandibular segments should be documented both in x-, y-, and z-axes and in terms of kind of movement (either linear or rotational movements). Lateral cephalometric, anteroposterior cephalometric, and submentovertex radiographs of 14 patients, treated with combined orthodontic and surgical treatment for skeletal class III malocclusion, were reevaluated retrospectively to demonstrate the applicability and usefulness of defined parameters in four maxillary and five mandibular movements. There was no clinically significant relapse in the follow-up period of 6 months in any of the patients. Differences between preoperative and postoperative measurements to demonstrate the linear movement in the z-axis, rotational movements in the x-axis and y-axis of the maxilla, and the linear movement in the z-axis of the mandibula were found to be statistically significant. Differences between early postoperative and late postoperative measurements to demonstrate rotational movement in the y-axis of the maxilla and rotational movement in the y-axis of the mandibula were found to be statistically significant. In this article, the possible tridimensional movements and cephalometric measurements of osteotomized bony segments after LeFort I and sagittal split osteotomy surgery were defined for better evaluation and follow up of the postoperative results.

Effects of maxillary molar intrusion with zygomatic anchorage on the stomatognathic system in anterior open bite patients

The aim of this study was to evaluate the effects of intrusion of the maxillary posterior teeth with zygomatic anchorage on the dentofacial system, on electromyographic (EMG) activity of the masticatory muscles, and on vibration of the temporomandibular joint. The study sample consisted of 19 subjects (13 females, 6 males) with a mean age of 17.7 years. Lateral cephalometric and posteroanterior (PA) radiographs, EMG, and electrovibratographic (EVG) records were obtained before (T0) and after (T1) intrusion. Paired t- and Wilcoxon signed ranks tests were used for statistical evaluation. Maxillary molar intrusion of 3.37 ± 1.21 mm was obtained with a force of 400 g in an average period of 6.84 ± 1.64 months. At T1, all measurements showed that facial growth direction, ANB angle, convexity, and overjet were decreased (P < 0.05). SNB angle, facial depth, and overbite were significantly increased (P < 0.05). Upper lip-E plane distance was increased (P < 0.05). Evaluation of the PA radiographs showed that the right and left molar reference angles were unchanged. EMG and EVG analysis showed that the stomatognathic system at T0 was maintained at T1. Intrusion of the maxillary posterior teeth with zygomatic anchorage is an effective treatment alternative for anterior open bite correction.

Condylar Disc Relationships and Vibration Energy in Asymptomatic Class I 9- to 12-Year Olds

A proper diagnosis is the key to successful treatment. The purpose of this study was to evaluate the temporomandibular joints (TMJ) by means of lateral and anteroposterior cephalograms, transcranial temporomandibular radiographs, magnetic resonance imaging (MRI), and TMJ electrovibratography (EVG) in asymptomatic and orthodontically untreated Angle Class I subjects. The study sample comprised 31 (13 boys, 18 girls) asymptomatic Class I children with a mean age of 9.7 years. The lateral cephalometric findings revealed that the subjects were mesofacial with an Angle Class I skeletal relationship, and the anteroposterior cephalograms showed a symmetrical craniofacial skeleton. Transcranial TMJ radiographs showed that the TMJs on both sides were symmetrically positioned. The time-frequency distributions of sounds from both right and left TMJs showed a wide range, and the vibrations measured by EVG were considerable. The MRI revealed unilateral disc displacement with reduction in four of the 31 subjects (13%), bilateral disc displacement with reduction in three subjects (10%), and bilateral disc displacement without reduction in one subject (3%). The data confirm that a standardized clinical examination to determine the status of the joint is not an efficient tool. This study suggests that the clinical diagnosis should be supported by extensive TMJ evaluation techniques.

Upper airway changes after Xbow appliance therapy evaluated with cone beam computed tomography.

OBJECTIVE To determine the treatment effects of the Xbow appliance on the upper airway dimensions and volume using cone-beam computed tomography (CBCT); to evaluate the cephalometric changes in the skeletal and dental structures of the skeletal Class II patients. MATERIALS AND METHODS The sample consisted of 25 Class II patients (11 male, 14 female) with a mean age of 11.1 ± 1.1 years. CBCT images were obtained at the beginning of the treatment (T0) and after the debonding of the Xbow (T1). RESULTS Changes in superior, middle, and inferior parts of the oropharynx in the retroglossal region and changes in the oropharyngeal airway volume were statistically significant (P < .05, P < .01). The differences favoring the Xbow for the changes in the direction of Class II correction included SNA, SNB, ANB, maxillary depth angles, and point A-NPg and Co-B distances. Data of the dental parameters showed palatal tipping and extrusion of the maxillary incisors, labial tipping of the mandibular incisors, and mesial movement and extrusion of the mandibular molars. CONCLUSIONS Treatment with the Xbow appliance in Class II patients resulted in favorable increase in the oropharyngeal airway dimensions and volume. Further studies with larger study samples and with control groups are needed.