Comperative evaluation of the current and new design miniplate fixation techniques of the advanced sagittal split ramus osteotomy using three-dimensional finite element analysis.

BACKGROUND: The aim of this study was to evaluate the stress occurring in the fixation systems both developed in various geometric designs for this study and currently used in sagittal split ramus advancement osteotomy using finite element analysis. MATERIAL AND METHODS: The finite element model that imitates three-dimensional sagittal split advancement osteotomy was fixed in 10 different miniplate fixation methods: one miniplate fixed with four monocortical screws in a horizontal and oblique pattern; four-hole two miniplates with eight monocortical screws; five-hole miniplate fixed with four monocortical and one bicortical screws; six-hole straight and curved miniplates fixed with six monocortical screws in different geometric designs. Unilateral masticatory muscle loads that have previously determined in the literature were applied to the model at the anatomical muscle attachment regions and the data obtained from finite element analysis and static linear analysis methods were recorded as Von mises, maximum principle and minimum principle stress values. RESULTS: It was observed from the results that maximum stress occurred in Group 1, which consisted of double backward T-shaped miniplate with 6-holes and, minimum stress occured in group 10, which mimiced hybrid system with one miniplate and four monocortical and one bicortical screws. CONCLUSIONS: Based on our results, the stress on the miniplates changes according to the geometric designs and the stress on the miniplate decreases as the numbers of miniplates and bars increase. The hybrid miniplate may be preferred by the surgeon as it will be exposed to less stress in excessive mandibular advancements by using the advantages of both the miniplate and the bicortical screw.

Management of a Benign Phyllodes Tumor in a 13-Year-Old Girl with Trans-position of the Nipple Areola Complex and Breast Reconstruction.

Phyllodes tumor is a rare primary tumor of the breast. In children and adolescents, it is even rarer with only 20 cases, treatment of which vary in the literature. Herein we report the case of a 13-year-old female patient with a giant benign phyllodes tumor eroding the bottom of the breast skin and causing nipple retraction. We performed breast conservative surgery by mobilizing the areola, using skin flaps and inserting an implant. Breast malignancy, including phyllodes tumor (PT), is very rare in adolescents. PT, previously called cystosarcoma phylloides, consists of leaf-like fronds, from which the tumor gets its name (1, 2). Although PT is most often seen in the fourth decade of life, almost 20 cases have been reported in the adolescent period, most of which are benign. The histologic types are benign, borderline, and malignant, depending on the mitotic rate of the tumor (3, 4).

Diagnosis of periodontal diseases using different classification algorithms: a preliminary study.

OBJECTIVE: The purpose of the proposed study was to develop an identification unit for classifying periodontal diseases using support vector machine (SVM), decision tree (DT), and artificial neural networks (ANNs). MATERIALS AND METHODS: A total of 150 patients was divided into two groups such as training (100) and testing (50). The codes created for risk factors, periodontal data, and radiographically bone loss were formed as a matrix structure and regarded as inputs for the classification unit. A total of six periodontal conditions was the outputs of the classification unit. The accuracy of the suggested methods was compared according to their resolution and working time. RESULTS: DT and SVM were best to classify the periodontal diseases with a high accuracy according to the clinical research based on 150 patients. The performances of SVM and DT were found 98% with total computational time of 19.91 and 7.00 s, respectively. ANN had the worst correlation between input and output variable, and its performance was calculated as 46%. CONCLUSIONS: SVM and DT appeared to be sufficiently complex to reflect all the factors associated with the periodontal status, simple enough to be understandable and practical as a decision-making aid for prediction of periodontal disease.

The multidisciplinary management of a fused maxillary central incisor with a talon cusp.

BACKGROUND: A fused maxillary incisor required complex multidisciplinary treatment to preserve health and restore aesthetics. This report presents a rare case of a dental fusion between the maxillary right central incisor and a supernumerary tooth of a 9-year-old male patient with the chief complaint of the presence of a large anterior tooth. METHODS: Radiographic investigation and computerized tomography indicated there was no connection between pulp chambers. After dividing the crown with a diamond bur, the supernumerary tooth was removed and the diastema between the maxillary central incisors was closed by orthodontic treatment. The tooth was then restored with composite resin. RESULTS: The maxillary right central incisor was still healthy after a follow-up examination period of 24 months. CONCLUSIONS: A multidisciplinary approach with the cooperation of different practitioners can contribute to the success of a treatment plan.

Screw fixation is superior to N-butyl-2-cyanoacrylate in onlay grafting procedure: a histomorphologic study.

The aim of this study is the histopathological evaluation of the efficiency of N-2-butyl cyanoacrylate in the fixation of bone block grafts on mandible. Autogenous monocortical block grafts taken from tibial bone were fixed to the outer surface of the angle of the mandible with N-2-butyl cyanoacrylate on the right side and mini screws on the left side. Postoperatively in the first and third months, six rabbits were killed and tissue samples were obtained from the grafted area. No significant difference was found between the cyanoacrylate and screw group with respect to inflammation or foreign body reaction. The level of graft necrosis was found to be significantly higher in the cyanoacrylate group than in the screw group in both the first and third month samples. Bone formation between the graft and recipient bone was evaluated and bone formation was found to be significantly higher in the screw group than in the cyanoacrylate group. No trabecular bone formation was observed between the graft and recipient bone in the cyanoacrylate group. Screw fixation was found to be superior to N-2-butyl cyanoacrylate in all parameters.

Distributions of 210Pb around a uraniferous coal-fired power plant in Western Turkey.

In the present study the spatial and the vertical distributions of 210Pb were investigated in the soils around a uranifereous coal fired power plant (CPP) in Yatagan Basin, in Western Turkey. The variation of 226Ra activity along the soil profiles was studied to assess the unsupported 210Pb distribution in the same samples. 226Ra was measured by gamma spectroscopy and 210Pb activities were determined from 210Po activities using radiochemical deposition and alpha spectroscopy. The total 210Pb activity concentrations in bulk core samples varied in the range of 38-250 Bq kg(-1) in the study sites and of 22-78 Bq kg(-1) in reference site. In the sectioned cores sampled from the study areas the ranges for activity concentrations of 226Ra, total 210Pb and unsupported 210Pb are 24-77; 39-344 and 4-313 Bq kg(-1), respectively. Corresponding ranges for reference site are 37-39; 39-122 and 1-83 Bq kg(-1).

A nomogram for predicting the degree of breast augmentation according to implant size.

Choosing the right implant size for a specific patient is a challenging aspect of breast augmentation. Bust circumference is obtained by measuring the chest circumference at the level of the nipple-areola complex. Pre- and postoperative bust circumference measurements obtained from 147 patients who underwent primary bilateral breast augmentation using round, textured, gel-filled implants were evaluated, and a practical reference list for future operations was developed. According to the results, each additional 100 ml in implant size yielded an approximate 2-cm increase in bust circumference. The authors believe these results gathered from systematic measurements may serve as a useful guide for choosing the right size implant for a satisfactory augmentation procedure.

Estimates of soil erosion using cesium-137 tracer models.

The soil erosion was studied by 137Cs technique in Yatagan basin in Western Turkey, where there exist intensive agricultural activities. This region is subject to serious soil loss problems and yet there is not any erosion data towards soil management and control guidelines. During the soil survey studies, the soil profiles were examined carefully to select the reference points. The soil samples were collected from the slope facets in three different study areas (Kirtas, Peynirli and Kayisalan Hills). Three different models were applied for erosion rate calculations in undisturbed and cultivated sites. The profile distribution model (PDM) was used for undisturbed soils, while proportional model (PM) and simplified mass balance model (SMBM) were used for cultivated soils. The mean annual erosion rates found using PDM in undisturbed soils were 15 t ha(-1) year(-1) at the Peynirli Hill and 27 t ha(-1) year(-1) at the Kirtas Hill. With the PM and SMBM in cultivated soils at Kayisalan, the mean annual erosion rates were obtained to be 65 and 116 t ha(-1) year(-1), respectively. The results of 137Cs technique were compared with the results of the Universal Soil Loss Equation (USLE).

Mandibular symphyseal distraction osteogenesis: review of three techniques.

Mandibular symphyseal distraction osteogenesis (MSDO) is an alternative strategy to correct mandibular transverse deficiencies and dental crowding. Only a limited number of practitioners have reported their clinical experience and potential complications of this procedure to widen the mandible in a large case series. This study involved retrospective analysis of 40 patients who underwent mandibular symphyseal distraction osteogenesis. Three different types of distractor were used to widen the mandible: tooth-borne in 21 patients, bone-borne in 5 patients and hybrid (both bone and tooth-borne) in 14 patients. The distraction amount ranged from 7 to 11 mm (mean 7.31 mm). While 39 patients underwent successful mandibular symphyseal distraction, there was one failure. Most of the complications were experienced in bone-borne distractors, such as breakage of the distractor rod, gingival recession, secondary infection and ptosis of the chin. In the light of these findings, it is suggested that a lingually placed tooth-borne hyrax appliance is more suitable and reliable than the other distraction devices. Further larger studies are needed in order to better evaluate the effectiveness of bone-borne or hybrid devices.

In vitro comparison of biomechanical characteristics of sagittal split osteotomy fixation techniques.

The aim of the present study was to compare the biomechanical stability of 10 different fixation methods used in sagittal split osteotomy. Twenty-five fresh sheep mandibles were stripped of all soft tissues and sectioned at the midline. A sagittal split osteotomy with 5mm advancement was performed on each hemimandible. The hemimandibles were randomly divided into 10 groups of 5, and then fixed with 5 different bicortical screws, 4 different miniplates with or without bicortical screws, and 1 resorbable screw configuration. All specimens were mounted on a specially designed 3-point biomechanical test model and compression loads were applied using the Lloyd LRX testing machine until 3mm displacement was reached. Load/displacement data were gathered and compared using the Mann-Whitney U-test with Bonferroni correction (P<0.01). The 3 bicortical screws in an inverted backward-L pattern provided the most biomechanical stability of the screw patterns tested. The miniplate fixed obliquely with 2 bicortical screws in the proximal segment provided the most biomechanical stability of the miniplate groups.

Primary dural melanomas: report of two cases and review of the literature.

Two cases of primary melanoma of the central nervous system originating from the dura mater and without involvement of the leptomeninges are described. In one case, the tumor was located extradurally with firm attachment to the dura mater and dural melanosis. In the other case, the dura was involved diffusely with multiple discrete masses of 1 to 3 mm in diameter. A literature review revealed five other cases of primary dural melanoma. A discussion of the origin of primary dural melanoma is presented.

Aneurysmal bone cysts of the occipital bone.

Two cases of aneurysmal bone cysts are reported. Each patient presented with a palpable mass in the occipital region and signs of compression of structures in the posterior fossa. One of the cases is unique, in that the aneurysmal bone cyst was associated with an epidural hematoma in the posterior fossa. The pertinent literature is reviewed.

Urgent total removal of a lower clival meningioma.

A 50-year-old woman was first examined in the emergency room because of inadequate ventilation, rapidly developing respiratory paralysis, and papilledema. Multiple cranial nerve palsies and tetraparesis were present. Carotid angiogram demonstrated bilateral ventricular dilatation. Facilities for computerized tomography and vertebral angiography were not available. Ventriculograms revealed a filling defect of the fourth ventricle without displacement of the midline structures. Immediate exploration of the posterior fossa through a suboccipital craniectomy permitted microsurgical excision of a meningioma of the lower clivus. Spontaneous respirations returned postoperatively and a complete return of neurological functions ensued. The pertinent literature is reviewed.

Post-herpetic aneurysm in the intrapetrosal portion of the internal carotid artery.

The occurrence of an aneurysm, 2 x 2.5 cm in size, in the intrapetrosal portion of the internal carotid artery in a 24-year-old female patient, during the course of herpes zoster ophthalmicus, is described.

Intracranial hydatid cysts. Study of 17 cases.

The authors report 17 cases of intracranial hydatid cyst out of 500 brain tumors seen in 20 years, and analyze clinical, investigative, diagnostic, and operative findings.