Structuring fault-tolerant object-oriented systems using inheritance and delegation

PhD ThesisMany entities in the real world that a software system has to interact with, e.g., for controlling or monitoring purposes, exhibit different behaviour phases in their lifetime, in particular depending on whether or not they are functioning correctly. That is, these entities exhibit not only a normal behaviour phase but also one or more abnormal behaviour phases associated with the various faults which occur in the environment. These faults are referred to as environmental faults. In the object-oriented software, real-world entities are modeled as objects. In a classbased object-oriented language, such as C++, all objects of a given class must follow the same external behaviour, i.e., they have the same interface and associated implementation. However this requires that each object permanently belong to a particular class, imposing constraints on the mutability of the behaviour for an individual object. This thesis proposes solutions to the problem of finding means whereby objects representing real-world entities which exhibit various behaviour phases can make corresponding changes in their own behaviour in a clear and explicit way, rather than through status-checking code which is normally embedded in the implementation of various methods. Our proposed solution is (i) to define a hierarchy of different subclasses related to an object which corresponds to an external entity, each subclass implementing a different behaviour phase that the external entity can exhibit, and (ii) to arrange that each object forward the execution of its operations to the currently appropriate instance of this hierarchy of subclasses. We thus propose an object-oriented approach for the provision of environmental fault tolerance, which encapsulates the abnormal behaviour of "faulty" entities as objects (instances of the above mentioned subclasses). These abnormal behaviour variants are defined statically, and runtime access to them is implemented through a delegation mechanism which depends on the current phase of behaviour. Thus specific reconfiguration changes at the level of objects can be easily incorporated to a software system for tolerating environmental faults

Avaliação de ruído em imagens radiográficas digitalizadas por meio do histograma

OBJETIVOS: Avaliar três equipamentos digitais em relação ao ruído agregado as imagens radiográficas digitalizadas contendo diferentes densidades ópticas. MATERIAL AND MÉTODO: Uma imagem radiográfica foi digitalizada seqüencialmente dez vezes usando dois escaneres (HP 4c/T and HP 5370C) e uma câmera digital (Nikon 990). Por meio do histograma foram medidos os valores de pixels e os desvios-padrões da região de interesse de cada imagem. Ambos valores foram utilizados para o cálculo do ruído nas diferentes densidades ópticas. RESULTADOS: Os valores encontrados para o ruído foram diferentes para cada equipamento e para cada densidade óptica. Houve uma diferença estatística significante entre os valores de ruído encontrados para o escaner HP 4c/T e a câmera digital (pTo evaluate the performance of three digital devices regarding the noise added to digital radiographic images containing different optical densities. METHODS: A radiographic image was digitized repeatedly ten times using two scanners (HP 4c/T and HP 5370C) and a digital camera (Nikon 990). A histogram tool measured a mean pixel value and the standard deviation of the region of interest in each image. Both values were used to calculate the image noise at the different optical densities. RESULTS: The noise values found were different for all devices and optical densities. There was a statistically significant difference (

Segmental resection vs. partial resection on treating solid multicystic ameloblastomas of the jaws – recurrence rates: a systematic review and meta-analysis

The aim of the present study was to compare the recurrence rates of solid multicystic ameloblastomas after segmental resection or marginal resection.PubMed, ScienceDirect, Web of Science, Scopus, Embase were searched for studies published up to July 2022. The gray literature was also searched. Meta-analysis was performed using OpenMeta Software, p< 0.05 considered significant.Among the search, 8 studies met all eligibility criteria. The group that underwent marginal resection was 1.1 times more likely to present recurrence of the lesion compared to the group that underwent segmental resection. There was no statistically significant difference between the two groups (segmental resection and marginal resection) in all eight studies regarding reducing ND (95% Confidence interval, 0.339 – 3.705; heterogeneity: Q value= 3.105; I2= 0%).The results showed that there was no statistically significant difference between segmental and marginal resection for the treatment of solid multicystic ameloblastomas; however, prospective studies with more rigorous methodological procedures are needed to better compare the surgical techniques

Avaliação de medidas lineares por meio de radiografia convencional e digitalizada no tratamento endodôntico

A radiologia digital tem sido amplamente difundida na odontologia, especialmente na endodontia. O sucesso do tratamento endodôntico depende das medidas lineares obtidas a partir de radiografias tomadas durante a odontometria, e do seguimento do comprimento de trabalho determinado até a obturação final. Este trabalho objetivou comparar a precisão das medidas lineares obtidas em radiografias convencionais com as imagens digitais indiretas avaliadas pelo programa Digora 1.5, durante as diferentes fases do tratamento endodôntico, bem como avaliar as ferramentas disponíveis neste programa. Foram analisadas 160 radiografias de dentes unirradiculares, dos arquivos da disciplina de Radiologia do departamento de estomatologia, da Faculdade de Odontologia de Bauru - USP, divididos em 4 grupos referentes a odontometria, prova do cone, comprobatória e obturação final. As análises das radiografias convencionais e das imagens digitalizadas foram realizadas por cinco examinadores previamente calibrados. Constatou-se um alto índice de concordância inter e intra-examinadores, respectivamente, por meio do coeficiente de concordância geral de Kendall e pelo índice de correlação. Os resultados relacionados às medidas lineares, submetidos à Análise de Variância a dois critérios e ao teste de Tukey, revelaram: quanto ao método, uma diminuição estatisticamente significante das medidas obtidas pelo método digital em relação à convencional (p < 0,05); e houve diferença estatisticamente significante entre a Fase 1 (odontometria) e a Fase 4 (obturação final) do tratamento endodôntico. Para a interpretação da imagem digitalizada, houve uma preferência estatísticamente significativa pela ferramenta de ajuste de Brilho e Contraste do programa Digora 1.5, analisado pelo teste de Friedman. Os resultados obtidos nesse estudo demonstraram que a imagem digitalizada proporcionou medidas lineares menores do que as realizados pelo método convencional, contudo não está ainda determinado se essa diminuição, corresponderia a uma maior acurácia do sistema, e, portanto, se traria maiores benefícios clínicos.INTRODUCTION: A successful endodontic therapy depends on the linear measurements obtained by means of radiographs taken during odontometry and also on the application of the established working length up to the final obturation. OBJECTIVE: The aim of this study was to compare the precision of the linear measurement obtained by means of conventional radiographs and indirect digital images evaluated by the Digora 1.5 software during the different stages of endodontic treatment, as well as to evaluate the tools available on this software. METHODS: A total of 160 radiographs of single-rooted teeth were obtained from files, which were analysed and divided in 4 groups comprising odontometry, cone fit, condensation and the final obturation. Analyses of the conventional radiographs and digitized images were performed by five previuosly calibrated examiners. RESULTS: A high level of inter and intra-examiner agreement was observed through application of the Kendall coefficient and the correlation index, respectively. In relation to the results of linear measurement, the two-way variance analyses and the Tukey test revealed that, concerning the method, a statistically significant decrease was observed on the measurement obtained through the digital method when compared to the conventional radiograph (

Assessment of spontaneous resolution of idiopathic bone cavity

Idiopathic Bone Cavity (IBC) or Simple Bone Cyst (SBC) is a non- epithelialized bone cavity with serosanguinous fluid content or empty. There is a literature debate regarding its pathogenesis that remains unclear. The main treatment option is the surgical exploration, although there are successful cases described in the literature in which just a follow-up with clinical and radiographic evaluation was performed. Objective: This study aimed to assess the spontaneous resolution of idiopathic bone cavity untreated by surgery. Material and Methods: Twenty-one patients diagnosed with surgically untreated IBC were submitted to a follow-up protocol modified from Damante, Guerra, and Ferreira5 (2002). A clinical and radiographic evaluation was performed in 13 patients (13/21), while eight patients (8/21) were only radiographically evaluated. Three observers evaluated the panoramic radiographs of 21 patients and the Kappa test was performed by intra and inter-examiners. Inductive and descriptive statistics were applied to the results. Results: Only one patient had a positive response to palpation and percussion of the teeth in the cyst area. Most of the cysts evaluated were rated as 3 (lesion “in involution”), 4 (lesion “almost completely resolved”), or 5 (“completely resolved”). Conclusions: We observed progressive spontaneous resolution of IBC. Most cysts were found in the recovery process in different follow-up periods. Patient's follow-up, without surgery, may be considered after the diagnosis based on epidemiological, clinical, and radiographic features of the lesion

Pyogenic granuloma on the upper lip: an unusual location

Pyogenic granuloma (PG) is a benign non-neoplastic mucocutaneous lesion. It is a reactional response to constant minor trauma and might be related to hormonal changes. In the mouth, PG is manifested as a sessile or pedunculated, resilient, erythematous, exophytic and painful papule or nodule with a smooth or lobulated surface that bleeds easily. PG preferentially affects the gingiva, but may also occur on the lips, tongue, oral mucosa and palate. The most common treatment is surgical excision. This paper describes a mucocutaneous PG on the upper lip, analyzing the clinical characteristics and discussing the features that distinguish this lesion from other similar oral mucosa lesions. The diagnosis of oral lesions is complex and leads the dentist to consider distinct lesions with different diagnostic methods. This case report with a 4 year-follow-up calls the attention to the uncommon mucocutaneous labial location of PG and to the fact that surgical excision is the safest method for diagnosis and treatment of PG of the lip, even when involving the mucosa and ski

CBCT location of the fusion between the buccal and lingual cortical in the mandibular ramus : importance to sagittal split osteotomy

Mandibular Sagittal Split Osteotomy (MSSO) is a popular technique in orthognathic surgery used both to advance and to retreat the mandible. However, MSSO may incur in important complications, such as bad splits and sensorineural injuries. Knowing the location of the fusion between the buccal and lingual cortical (FBLC) in the mandibular ramus and the bone thickness in the region where osteotomies will be performed is determinant in MSSO planning to avoid complications. The aim of this study was to document and evaluate possible differences between sexes regarding the location of the FBLC in relation to the superior cortical of mandibular foramen (MF) and bone thickness in the region of interest for MSSO in a Brazilian population. Eighty five cone-beam Computed Tomography (CBCT) scans were used to perform linear measurements to determine the location of the FBLC. Bone thickness from the mandibular canal (MC) to the cortical external surfaces and the diameter of the MC were measured at three different points: mandibular ramus (A), mandibular angle (B) and mesial of the second molar (C). The FBLC was located at a mean distance of 8.3 mm from the superior cortical of the MF in males and 8.1 mm in females. There was no difference between males and females regarding the mean bone thickness from the MC to the buccal external surface at all the points investigated (p >>0.05). Bone thickness from the lingual external surface to the MC was bigger among females than males in regions B and C (p<0.05). The diameter of the MC was bigger among males in regions B and C. Sexual dimorphism regarding mandibular bone thickness but not regarding the location of FBLC was present. This fundamental knowledge may assist to the panning of MSSO

Visibility of the mandibular canal on CBCT crosssectional images

The identification of the mandibular canal (MC) is an important prerequisite for surgical procedures involving the posterior mandible. Cone beam computed tomography (CBCT) represents an advance in imaging technology, but distinguishing the MC from surrounding structures may remain a delicate task. OBJECTIVES: The aim of this study was to assess the visibility of the MC in different regions on CBCT cross-sectional images. MATERIAL AND METHODS: CBCT cross-sectional images of 58 patients (116 hemi-mandibles) were analyzed, and the visibility of the MC in different regions was assessed. RESULTS: The MC was clearly visible in 53% of the hemi-mandibles. Difficult and very difficult visualizations were registered in 25% and 22% of the hemi-mandibles, respectively. The visibility of the MC on distal regions was superior when compared to regions closer to the mental foramen. No differences were found between edentulous and tooth-bearing areas. CONCLUSIONS: The MC presents an overall satisfactory visibility on CBCT cross-sectional images in most cases. However, the discrimination of the canal from its surrounds becomes less obvious towards the mental foramen region when cross-sectional images are individually analyzed

Visibility of the mandibular canal on CBCT crosssectional images

The identification of the mandibular canal (MC) is an important prerequisite for surgical procedures involving the posterior mandible. Cone beam computed tomography (CBCT) represents an advance in imaging technology, but distinguishing the MC from surrounding structures may remain a delicate task. OBJECTIVES: The aim of this study was to assess the visibility of the MC in different regions on CBCT cross-sectional images. MATERIAL AND METHODS: CBCT cross-sectional images of 58 patients (116 hemi-mandibles) were analyzed, and the visibility of the MC in different regions was assessed. RESULTS: The MC was clearly visible in 53% of the hemi-mandibles. Difficult and very difficult visualizations were registered in 25% and 22% of the hemi-mandibles, respectively. The visibility of the MC on distal regions was superior when compared to regions closer to the mental foramen. No differences were found between edentulous and tooth-bearing areas. CONCLUSIONS: The MC presents an overall satisfactory visibility on CBCT cross-sectional images in most cases. However, the discrimination of the canal from its surrounds becomes less obvious towards the mental foramen region when cross-sectional images are individually analyzed

Avaliação da relação entre o ângulo horizontal do côndilo e o desarranjo interno da ATM, por meio de ressonância magnética

This research aimed at assessing the relation between the horizontal condylar angle (HCA) and the internal derangement (ID) of the temporomandibular joint (TMJ), as a result of interference by the TMJ disk, in individuals undergoing magnetic resonance (MR) scans. The sample included a total of 144 TMJs (sagittal and coronal views) of 72 subjects, 15 of whom were male and 57 female, with ages ranging from 15 to 70. The scans were made in a Signa system (GE) model at a magnetic field magnitude of 1.5 T. Sixty-eight TMJs were found to be normal, while 46 showed anterior displacement with reduction. Of these, 41 had some kind of adaptive change in the condyle, while 5 showed degenerative changes. Anterior displacement without reduction was found in 29 joints, 12 of which showed adaptative changes in the condyle, while 17 showed degenerative changes. Only one posterior displacement of the articular disk was recorded. For the TMJs in which disk displacement was found, such values achieved 24.69º on the right side, and 22.94º on the left side. Hence, it was possible for us to conclude that the HCA tends to increase in those TMJs where ID is present. For contralateral TMJs, a strong association was observed between HCA values (57.8%), state of normality (69.7%), and ID (66.7%). To corroborate such findings, a correlation between contralateral HCA values (63.31%) and the diagnosis for contralateral TMJs (68.05%) was determined. Thus, we could infer that there is a tendency between contralateral TMJs to share characteristics and conditions.Esta pesquisa teve por objetivo avaliar a relação entre o valor do ângulo horizontal do côndilo (AHC) e o desarranjo interno (DI), por interferência do disco da articulação temporomandibular (ATM), de indivíduos indicados para exame por ressonância magnética (RM). A amostra perfez um total de 144 ATMs (cortes sagital e coronal) de 72 indivíduos, na faixa etária de 15 a 70 anos, 15 do gênero masculino e 57 do gênero feminino. Os exames foram procedidos em um sistema modelo Signa (GE), magnitude de 1,5 T para o campo magnético. Sessenta e oito ATMs apresentaram uma condição de normalidade e 46 apresentaram deslocamento anterior do disco articular com redução. Dessas, 41 expressaram algum tipo de alteração adaptativa no côndilo e cinco, alterações degenerativas. Vinte e nove articulações mostraram deslocamento anterior do disco articular sem redução, sendo que 12 dessas apresentaram alterações adaptativas do côndilo e 17, alterações degenerativas. Foi registrado apenas um caso de deslocamento posterior do disco articular. O valor médio encontrado para o AHC do lado direito foi de 22,09º e para o lado esquerdo foi de 21,47º, para aquelas ATMs que se apresentaram em condições de normalidade. Para as ATMs com deslocamento de disco, esses valores foram de 24,69º para o lado direito e 22,94º para o lado esquerdo. Desse modo, foi-nos possível concluir que existe uma tendência ao aumento do AHC nas ATMs com DI. Observamos forte associação, para as ATMs contralaterais, entre os valores do AHC (57,8%), condição de normalidade (69,7%) e DI (66,7%). E, corroborando esses resultados, registramos correlação para os valores dos AHC contralaterais (63,31%) e o diagnóstico para as ATMs contralaterais (68,05%). Assim, pudemos inferir que existe tendência das ATMs contralaterais apresentarem as mesmas características e condições