Mustafa Sancar Ataç

A case report comparing 3-D evaluation in the diagnosis and treatment planning of hemimandibular hyperplasia with conventional radiography.

INTRODUCTION Cephalometric radiography is the main investigation used in the diagnosis of maxillofacial deformities. Three-dimensional (3-D) computed tomography (3-D CT) imaging has recently been used in the diagnosis and treatment planning of craniofacial morphology. The purpose of this report was to present the diagnosis and treatment planning of a hemimandibular hyperplasia case by using conventional radiographs and 3-D cephalometric analysis. METHODS A 24-year-old girl presented with hemimandibular hyperplasia and the main complaint was her facial appearance. Conventional cephalometric analysis including lateral and frontal cephalograms were traced by hand and evaluated by the same clinician. Twenty-one measurements on the lateral cephalograms and 13 measurements on the frontal cephalograms were performed. In addition, axial images were reconstructed into a 3-D model by using medical image processing software. Linear and angular measurements were presented in coronal and sagittal planes. RESULTS The 3-D CT analysis has a superior image quality when compared with conventional cephalograms. CONCLUSIONS The 3-D CT analysis provides more advanced diagnostic image information in evaluating craniofacial morphology. We conclude that 3-D CT images can facilitate the diagnosis, treatment planning, and outcome evaluation of severe asymmetry cases.

Comparison of biomechanical behaviour of maxilla following Le Fort I osteotomy with 2- versus 4-plate fixation using 3D-FEA. Part 1: Advancement surgery

The study aimed to calculate the location and intensity of the maximum stress fields on the fixation plates and surrounding maxilla following Le Fort I osteotomies after advancement procedures using three-dimensional finite element analysis. The models were generated using skull CT scan data. Le Fort I osteotomy simulations were made and two separate impacted maxillary models were designed. The ADV-2 model has 2 plate fixations bilaterally at the piriform rims, the ADV-4 model has 4 plate fixations at the zygomatic buttresses and piriform rims. The stress fields on bone, plate and screws were computed for each model. Posterior occlusal loads were simulated on one side in the molar-premolar region, in all three directions, reflecting the chewing forces. The increased locations of highest Von Mises stresses on the plates and highest maximum principle stresses on the bones were determined in ADV-2 models especially under horizontal and oblique loads when compared with ADV-4 models. Evaluation of the highest Von Mises stress values and maximum principal stress revealed that oblique load in the ADV-2 model received the highest values. 4-plate fixation following Le Fort I advancement surgery exerts less stress on the maxillary bones and fixation materials than 2-plate fixation.

The effect of drill-free and drilling methods on the stability of mini-implants under early orthodontic loading in adolescent patients

The aim of this study was to compare the stability of mini-implants using drill-free and drilling methods, both before and after early force loading. Sixty-two adolescent patients (24 males and 38 females, mean age 15.7 ± 4.2 years) were randomly assigned to three groups and 112 titanium mini-implants were placed between the upper first molars and second premolars to achieve molar distalization. Groups I (n = 22) and II (n = 20) received pilot drilling with diameters of 1.1 and 0.9 mm, respectively, while the drill-free method was used in group III (n = 20). Distalization forces of up to 200 g were applied with nickel-titanium (NiTi) open coil springs. The Z-test was used for statistical analyses to compare the success rates of the groups with each other. The overall success rate was 77.7 per cent. There was no significant difference between groups I and II either before or after loading. Significant differences were found between groups I and III (P = 0.0002) and between groups II and III (P = 0.045) both before and after loading. Mini-implants using the drill-free method provided the highest success rate before orthodontic force application and also maintained their stability after early loading for 1 month during orthodontic treatment. Smaller drill diameters can contribute to clinical stability of mini-implants in the short-term, however long-term evaluations are needed to clarify the stability of temporary skeletal anchorage devices throughout orthodontic loading.

Stability of surgically assisted rapid maxillary expansion and orthopedic maxillary expansion after 3 years' follow-up

OBJECTIVE To evaluate the stability of surgically assisted rapid palatal expansion (SARME) and orthopedic maxillary expansion (OME) after 3 years of follow-up, and compare these changes with a control group. MATERIALS AND METHODS The subjects of the study were divided into three groups. Group 1 was composed of 10 patients (6 males, 4 females) with a mean age of 15.51 years (range: 13.33-17.58 years) and treated with OME, Group 2 comprised 10 patients (7 males, 3 females) with a mean age of 19.01 years (range: 16.25-25.58 years) and treated with SARME. Group 3 was the control group, consisting of 10 untreated, skeletal Class 1 subjects (6 males, 4 females) with a mean age of 15.27 years (range: 13.42-17.00 years) and matched to the OME group for sex and age. Lateral cephalometric and posteroantererior films were taken before expansion (T1), postexpansion (T2), and 3 years after the retention period (T3). RESULTS After OME and SARME, significant increases were observed for both dental and skeletal transverse widths (P < .01). After 3 years of follow-up, maxillary basal width decreased 1.35 +/- 0.44 mm in the SARME group and 1.19 +/- 0.41 mm in the OME group, while upper molar width decreased 2.23 +/- 1.24 mm in the SARME group and 2.79 +/- 1.01 mm in the OME group. CONCLUSIONS Both the OME and SARME procedures remained stable after 3 years of follow-up with some amount of postretention relapse, compared with the control group.

Changes in nasal structures following orthopaedic and surgically assisted rapid maxillary expansion

The aim of this study was to investigate and compare changes in the nasomaxillary complex substructures following orthopaedic rapid maxillary expansion (RME) and surgically assisted RME (SARME). 10 patients received RME, 10 patients received SARME, and 10 patients served as an untreated control group. Lateral and posteroanterior cephalograms were obtained for each individual at pre-expansion/pre-control (T1) and post-expansion/post-control (T2). Descriptive parameters and transversal measurements on maxillo-mandibular dentoalveolar structures and skeletal bases, right and left nasal cavity angles (NC/Lom/VL and CN/Lom/VL, respectively), total nasal cavity angle (NC/Lom/CN), nasal cavity width (NC-CN) and nasal septum angle (sn/Lom/VL) were also calculated. Paired t-tests were used to evaluate changes within groups following treatment/control. Analysis of variance (ANOVA) and Duncans tests were used to compare changes between groups. With the exception of nasal septum deviation, all nasal parameters significantly increased following RME and SARME. The increases in the SARME group were greater than in the other groups, but no statistically significant differences were recorded between the RME and SARME groups. Neither RME nor SARME created positional changes in the nasal septum.

Comparison of biomechanical behaviour of maxilla following Le Fort I osteotomy with 2- versus 4-plate fixation using 3D-FEA

The aim of the second part of this study was to evaluate the mechanical behaviour of 2- versus 4-plate fixation and bony structures after Le Fort I impaction surgeries using three-dimensional finite element analysis (3D-FEA). Two 3D-FEA models were created to fixate the impacted maxilla at the Le Fort I level as 2-plate fixation at the piriform rims (IMP-2 model) and 4-plate fixation at the zygomatic buttresses and piriform rims (IMP-4 model). The IMP-2 model contained 225664 elements and 48754 nodes and the IMP-4 model consisted of 245929 elements and 53670 nodes. The stresses in each maxillary model were computed. The models were loaded on one side, at the molar-premolar region, in vertical, horizontal and oblique directions to reflect the chewing process. It was concluded that the use of 4-plate fixation following Le Fort I advancement surgery provides fewer stress fields on the maxillary bones and fixation materials than 2-plate fixation from a mechanical point of view.

Comparison of biomechanical behaviour of maxilla following Le Fort I osteotomy with 2- versus 4-plate fixation using 3D-FEA: Part 3: Inferior and anterior repositioning surgery

Having studied the effect of maxillary advancement and maxillary impaction in parts 1 and 2 of this research, the purpose of this study was to investigate the biomechanical behavior of different fixation models in inferiorly and anteriorly repositioned maxilla following Le Fort I osteotomy. Two separate three-dimensional finite element models, simulating the inferiorly advanced maxilla at Le Fort I level, were used to compare 2- and 4-plate fixation. Model INF-2 resulted in 247,897 elements and 53,247 nodes and INF-4 consisted of 273,130 elements and 59,917 nodes. The stresses occurring in and around the bone and plate-screw complex were computed. The highest Von Mises stresses on the plates and maximum principal stresses on the bones were found in INF-2, especially under horizontal and oblique loads, when compared with INF-4. The present biomechanical study shows that the traditionally used 4-plate fixation technique, following Le Fort I inferior and anterior repositioning surgery, without bone grafting, provides fewer stress fields on the maxillary bones and fixation materials.

Changes in nasopharyngeal airway following orthopedic and surgically assisted rapid maxillary expansion.

Introduction:The aim of this study was to compare changes in soft-palate morphology and nasopharyngeal relations after orthopedic rapid maxillary expansion (RME) and surgically assisted RME (SARME). Methods:A group of 10 patients received RME, a second group of 10 patients received SARME, and a third group of 10 patients served as an untreated control group. Lateral and posteroanterior cephalograms were obtained for each individual at preexpansion/precontrol and postexpansion/postcontrol. In addition to descriptive parameters, the angulation, length, and thickness of the soft palate and superior and inferior pharyngeal spaces and the ratios of the length of the soft palate to the length of the superior and inferior pharyngeal spaces were evaluated. Paired t-tests were performed to analyze changes within groups, and analysis of variance and Duncan tests were used to compare changes among groups. Results:No statistically significant differences were found in changes in measurements related to soft-palate morphology or nasopharyngeal dimensions among the SARME, RME, and control groups; however, increases in soft-palate angulation and superior and inferior pharyngeal spaces after expansion/control were greater in the SARME group than in other groups. Conclusions:No statistically significant differences were found between changes in the nasopharyngeal airway after RME and SARME.

Osteotomy assisted maxillary posterior impaction with miniplate anchorage.

This case report presents orthodontic treatment with miniplate anchorage accelerated by osteotomy-assisted maxillary posterior impaction in a severe open bite case. A 14-year-old girl with a severe anterior open bite was treated by intrusion of the maxillary posterior teeth. A segmental osteotomy was applied, and the miniplates were fixed to the zygomatic buttress area. The intrusive force was applied with nickel-titanium closed coil springs using a force of 250 g between the miniplates and the upper first and second molar buccal tubes. The intrusion was completed 2.5 months after osteotomy. The treatment was continued with the fixed orthodontic appliances and completed after 12 months. At the end of treatment, optimal occlusion and the correction of the anterior open bite were achieved. The maxillary molars were impacted 4.0 mm, and the mandibular plane showed a counterclockwise autorotation of 3.0 degrees . The results showed that osteotomy-facilitated orthodontic treatment clearly reduced the treatment time and had no adverse effects. In conclusion, this one-stage osteotomy technique can be an effective option to help molar intrusion in severe open bite cases.

A suspected case of malignant hyperthermia after tooth extraction: case report.

w e t d d s c e t c Malignant hyperthermia (MH) is a rare, life-threatening, hereditary skeletal muscle disorder characterized by a hypermetabolic response following exposure to potent, volatile anesthetics or depolarizing muscle relaxants, such as halothane, desflurane, sevoflurane, and succinylcholine. MH is associated with genetic mutaions of the ryanodine receptor gene (RYR1), which odes the skeletal muscle calcium-release channel. Inreased Ca concentrations in extracellular fluid play n essential role in the pathogenesis of MH. A number of serious clinical signs can be observed during an MH onset, including generalized muscular rigidity, masseter muscle spasm, brown-colored urine, increased carbon dioxide production, increased oxygen consumption, metabolic and respiratory acidosis, and heat stroke. The speed of an MH attack may vary, with the first clinical symptoms observable within minutes after administration of the drug in some cases and a delay of several hours in others. Early diagnosis and appropriate management play a critical role in the successful treatment of MH. Hyerventilation with oxygen, intravenous administraion of dantrolene, and external body cooling are vital teps in the medical management of a severe attack. Dantrolene prevents calcium-related muscle contractions by inhibiting calcium release from the sarcoplasmic reticulum of skeletal muscle; however, given the