Análise de algoritmos computacionais utilizados em sistemas de planejamento de braquiterapia de alta taxa de dose: estudo comparativo com o Código MCNP-5C

In radiotherapy, computational systems are used for radiation dose determination in the treatment’s volume and radiometric parameters quality analysis of equipment and field irradiated. Due to the increasing technological advancement, several research has been performed in brachytherapy for different computational algorithms development which may be incorporated to treatment planning systems, providing greater accuracy and confidence in the dose calculation. Informatics and information technology fields undergo constant updating and refinement, allowing the use Monte Carlo Method to simulate brachytherapy source dose distribution. The methodology formalization employed to dosimetric analysis is based mainly in the American Association of Physicists in Medicine (AAPM) studies, by Task Group nº 43 (TG-43) and protocols aimed at dosimetry of these radiation sources types. This work aims to analyze the feasibility of using the MCNP-5C (Monte Carlo N-Particle) code to obtain radiometric parameters of brachytherapy sources and so to study the radiation dose variation in the treatment planning. Simulations were performed for the radiation dose variation in the source plan and determined the dosimetric parameters required by TG-43 formalism for the characterization of the two high dose rate iridium-192 sources. The calculated values were compared with the presents in the literature, which were obtained with different Monte Carlo simulations codes. The results showed excellent consistency with the compared codes, enhancing MCNP-5C code the capacity and viability in the sources dosimetry employed in HDR brachytherapy. The method employed may suggest a possible incorporation of this code in the treatment planning systems provided by manufactures together with the equipment, since besides reducing acquisition cost, it can also make the used computational routines more comprehensive, facilitating the brachytherapy ...

Avaliação da prevalência do tipo de crescimento crânio facial nas diferentes más oclusões, de acordo com a classificação de angle

During the orthodontic correction planning in addition to dental-jaw correction, facial aesthetics is the orthodontist's and patient's major concern. To prevent facial aesthetics damage is really important to take into account the type of craniofacial growth: mesofacial (balanced), dolichofacial (vertical) or brachyfacial (horizontal). We evaluated 152 documentation files from the Department of Orthodontics of Dental University of Sao Jose dos Campos- UNESP in order to analyze what kind of growth occurs in most Class I malocclusions, Class II and Class III Angle of treated individuals from 6 to 12 years old. From the randomly collected samples, 15 of them belonged to Class I Angle malocclusions; 123 belonged to Angle Class II and 14 to Class III malocclusion. The results showed that in Class I, 66.67% were classified as dolicocephalic; in Class II, 64.23% were classified as dolicocephalic and in Class III, 50% were brachycephalic. We conclude that the dolichofacial was the type which ocurred the most, both in females and males and both in malocclusion Class I and Class II. The brachyfacial type most occurred in Class III malocclusion and the mesofacial type occurred in smaller numbers in the three malocclusions studied

Programação linear no planejamento do tratamento de câncer por radiocirurgia

Medical Physics has been reaching an important role among several lines in Science, providing means for the improvement of several theories and procedures. Currently, its main application is related with the use of ionizing radiations, specially, in treatment procedures such as Radiotherapy. Radiosurgery is a Radiotherapy technique which consists in administering a single tumoricidal dose of radiation exclusively to the tumorous lesion. It becomes then an interesting alternative to surgical treatment, mainly in cerebral metastases, which are the most frequent cerebral tumors in the central nervous system. The radio neurosurgical team works out a planning for the Radiosurgery treatment, aiming for obtaining an appropriate ideal treatment for each case. For the working out of this treatment planning, Computed Tomography images of the region to be treated are obtained, digitalized and later, fused with nuclear magnetic resonance images. Through these images, critical structures, organs at risk and lesions are localized. After this, calculations are made to determine three-dimensional positions of isocenters, isodose curves, prescribed dose, collimators sizes, position, numbers and respective weight of isocentric conformal fields, and others. The treatment planning is commonly based in desired levels of dose for specific types of tumors and organs at risk concerning the irradiated region. Theses levels of dose are chosen in a way that a high probability of cure may be achieved and meanwhile, that the probability of complications, in whichever organ at risk, may be minimal. Thus, many researches have been carried out, showing that mathematical techniques may help to obtain an optimal planning for the treatment of cerebral metastases. Among the methods of optimization in the study...(Complete abstract click electronic access below)

Análise da viabilidade de simulações com feixes de prótons de 100, 150, 200 e 250 MeV em alvos heterogêneos

In the recent years, the use of proton beams in radiotherapy has been an outstanding progress (SMITH, 2006). Up to now, computed tomography (CT) is a prerequisite for treatment planning in this kind of therapy because it provides the electron density distribution required for calculation of dose and the interval of doses. However, the use of CT images for proton treatment planning ignores fundamental differences in physical interaction processes between photons and protons and is, therefore, potentially inaccurate (SADROZINSKI, 2004). Proton CT (pCT) can in principle directly measure the density distribution needed in a patient for the dose distribution (SCHULTE, et al, 2004). One important problem that should be solved is the implementation of image reconstruction algorithms. In this sense, it is necessary to know how the presence of materials with different density and composition interfere in the energy deposition by ionization and coulomb excitation, during its trajectory. The study was conducted in two stages, was used in both the program SRIM (The Stopping and Range of Ions in Matter) to perform simulations of the interaction of proton beams with pencil beam type. In the first step we used the energies in the range of 100-250 MeV (ZIEGLER, 1999). The targets were set to 50 mm in length for the beam of 100 MeV, due to its interaction with the target, and short-range, and 70 mm for 150, 200 and 250 MeV The target was composed of liquid water and a layer of 6 mm cortical bone (ICRP). It were made 9 simulations varying the position of the heterogeneity of 5 mm. In the second step the energy of 250 MeV was taken out from the simulations, due to its greater energy and less interaction. The targets were diminished to 50 mm thick to standardize the simulations. The layer of bone was divided into two equal parts and both were put in the ends of the target... (Complete abstract click electronic access below)

Seqüelas em dentes permanentes após trauma nos predecessores decíduos e sua implicação clínica

In regarding to the high prevalence of traumatic dental injuries in primary teeth and the possible disturbances on developing permanent successor germs, an early diagnosis and an adequate establishment of treatment planning are very important to minimize the damage caused by the trauma. Sequelaes can affect the coronal portion (white or yellow-brown discoloration associated or not with enamel hipoplasia, dilacerations of the crown), the root portion (dilaceration, duplication or cessation of root formation) or the whole successor permanent tooth (odontoma sequestration or disturbances of permanent successor eruption). The aim of this study is to make a literature review of the developmental disturbances of permanent teeth followed by traumatic injuries to theirs primary predecessors and to present cases reports to advise the dentists, their patients and parents about the damage that developing permanents teeth can undergo.

Mudanças dento-esquelétics naturais e decorrentes do tratamento ortopédico da má oclusão de Classe II

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Prevalência das más oclusões em crianças na clínica de graduação da Faculdade de Odontologia de Araraquara - UNESP

The aim of this study was to evaluate in dental models the occlusal relationship of children treated or in orthodontic treatment of the Undergraduate Clinic of Araraquara Dental School – UNESP. It was analyzed the vertical, anteroposterior and transversal relationships of the casts models of 388 children by two previous calibrated examiners. The results were analyzed by descriptive statistics and it was found higher prevalence of occlusal deviations in the vertical direction, followed by the sagital dimension and in lower prevalence of the transverse direction.

Tendência de crescimento facial em ortodontia e ortopedia funcional dos maxilares

The knowledge of the facial growth trend is very important in orthodontic treatment. A lateral headfilm is recommended in all young patients undergoing a preorthodontic guidance program to anticipate the best time to begin any mechanical procedures and the possibilities to determine the type of facial growth trend. In type A it will be observed that the middle and lower face are growing forward and downward in unison, with no change in ANB angle. Type B growth trends reveals that growth is downward and forward, with the middle face growing forward more rapidly than the lower and in type C the lower face is growing downward and forward more rapidly than the middle face revealing a decrease in the size of the ANB angle.

Alternativa de tratamento simplificado e integrado da retenção intraóssea de incisivo central superior, associada a odontoma: relato de caso

Permanent teeth impaction is highly prevalent among brazilian people. Its etiology is related to local and general factors association. Permanent teeth retention compromises dental occlusion and when anterior teeth are involved, it also brings esthetics impairments which lead to psychological disturbance. Early diagnosis and adequate treatment are extremely important to solve not only occlusal problems but also psychological aspects. Orthodontic traction of impacted teeth can be conducted by using fixed or removable appliances. Although it depends on patient compliance the use of removable appliances provides an anchorage based on the teeth and the palate reducing undesirable side effects. This paper describes the case of a fourteen years old female patient whose right maxillary central incisor was adequately tractioned with a removable orthodontic appliance. Removable orthodontic devices were used at first to reposition teeth in maxillary anterior area what provided adequate space to allow the placement of the impacted incisor and after were also used to traction and position this tooth. The procedure described seemed to be effective, non expensive and a viable treatment to be performed even on the scope of public health services, extending orthodontic treatment to a higher number of patients.

Facial type measurements influence on transverse dimensions of normal occlusion arches

Objective – To correlate facial type measurements of Caucasian individuals with transverse dimensions of normal occlusion arches. Methods – Twenty-one pairs of dental models were selected according to the following inclusion criteria: presence of all permanent teeth from 1 st molar to 1 st molar; normal occlusion; no prosthetic crowns; no previous orthodontic treatment and 2 mm or less of crow- dings or spacings. The cephalometric measurements of lateral cephalometric X-ray of the same individuals were taken and tabulat ed. To evaluate the repetition of arch measurements, paired Student’s t-test and Pearson's correlation coefficient were used. The r elationship between the measurements was analysed by using the Pearson’s correlation. Results – The repetition of the measurements showed high correlation and no systematic error. In the comparison between the measurements, a moderate negative correlation was observed b et- ween facial axis angle and the measurements Upper and Lower 6-6, whereas a positive correlation was observed between dentition height and the latter. Conclusion – It was observed a negative correlation between facial axis angle and upper and lower inter-molar distance as well as a positive correlation between dentition height and upper and lower inter-molar distance.

Aparelho Herbst x osteotomia sagital mandibular bilateral no tratamento do padrão II, classe II, divisão 1 em adultos: relato de casos

Two treatment options are available for adult patients with skeletal Class II malocclusion caused by mandibular deficiency: combined mandibular advancement surgery and orthodontic treatment or mandibular advancement appliance. This study aimed to analyze the effects of two therapeutic modalities of Class II malocclusion treatment with mandibular deficiency. Two distinct individuals with Class II malocclusion division 1 and mandibular deficiency were treated after growth spurt. The first individual used the Herbst appliance as a therapeutic option and the second individual was treated with bilateral sagittal osteotomy. The cephalometric, occlusion and face results were evaluated for both individuals. Correction of Class II malocclusion was observed on both Herbst and surgery patients resulting on a normal occlusal relationship with normal overjet and overbite. Therefore it was concluded that Herbst appliance can be used to treat borderline skeletal Class II in adult patients.

Fechamento de diastema anterior: associação de procedimentos ortodôntico e restaurador

Several aspects beyond the restorative phase itself such as orthodontic movement and periodontal treatment must be considered in cases of closure of diastemas. In such cases, a multidisciplinary approach is essential. As patients during orthodontic treatment may show high risk of developing dental caries and periodontal disease, inflammation of the gingival tissue is a common finding. For this reason, a preliminary basic periodontal treatment is critical to the success of restorative procedure. In addition, postoperative care and instruction in phonetics, oral hygiene and periodic control must be considered by professionals and patients. Thus, this paper demonstrates through a case report, pre and postoperative issues that should be considered during the closure of diastemas using a layering technique with resin composites

Tratamento da classe II divisão 2 com aparelho de Herbst após o pico de crescimento puberal

Patients with Class II division 2 malocclusion and mandibular retrusion have limited treatment options after the growth peak, such as surgical-orthodontic treatment or mandibular advancement devices. Among bite-jumping devices, the Herbst appliance allows greater increase of mandibular growth since it does not require patient compliance and allows continuous use. This case report presents the treatment of a Class II division 2 malocclusion in a patient after growth peak, performed in two stages. The first stage included the upper incisors proclination and overjet increase with multibracket appliance to benefit next stage. The second stage involved mandibular advancement using Herbst appliance aiming to correct the Class II molar relationship. The treatment resulted in a stable occlusion with periodontal health, normal functions and facial aesthetics improvement. Dental and skeletal changes arising from treatment could be assessed by cephalometric analysis and superimposition of pretreatment and post-treatment cephalometric tracings. Antero-posterior discrepancy was corrected by means of dental movement as well as by mandibular growth increment stimulated by the Herbst appliance.

External apical root resorption in retracted incisors

AIM: To evaluate the occurrence of external apical root resorption (EARR) in the incisors after anterior retraction in corrective orthodontic treatment with first premolar extractions and whether it was related with the type of root apex movement and its inclination. METHOD: The maxillary and mandibular incisors of 22 patients (12 to 25 years of age; 9 males and 13 females) were treated with fixed appliances and premolar extraction. EARR was defined as the difference in root length before and after incisal retraction on periapical radiographs. Distortion of radiographic images and changes due to incisal tipping were controlled for. Pre- and post-incisal retraction lateral cephalometric radiographs established the relationship between EARR and the tipping of the incisors, along with the vertical, horizontal, and total movement of the root apex. RESULTS: There was significant EARR (1.51 to 2.37 mm) during incisor retraction, but this was not related to the movement or the tipping of the root apex of almost all teeth. It was observed that after the retraction stage, EARR occurred in all evaluated incisors, but it was more significant (P < .05) in the mandibular right lateral incisor. CONCLUSION: The EARR that did occur was unrelated to movement or tipping of the root apex, except for the vertical root apex movement of the mandibular left central incisor and the inclination of the maxillary right lateral incisor.

Estabilidade oclusal a longo prazo de Classe II, divisão 1, após tratamento com extração de pré-molares

Patients are looking for esthetic and functional changes when seeking orthodontic treatment and expect the remaining of a stable occlusion. Occlusion stability is one of the goals of the orthodontist; however, dental relationships changes in long-term can occur leading to a relapse of the treatment. Teeth and shape of arches tend to return to the original form, been the retention phase important after the appliance removal, even after several years of post-treatment. This article approaches a submission of a clinical case of Class II division 1 treated with extraction of premolars analyzing its long-term stability.