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1.
Radiologe ; 60(1): 77-92, 2020 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-31919535

RESUMO

Despite the increasing use of modern digital cross-sectional imaging techniques (especially digital volume tomography) in dental X­ray examinations, orthopantomography remains the widely available, commonly used basic imaging modality for evaluating dental status prior to extensive treatment. It is also used for inflammatory and tumorous odontogenic osseous pathologies which are demonstrated with typical imaging findings. The classical X­ray tomography principle has been further developed for the presentation of the differently wide, shape variants of dental arches. The examination unit, consisting of a rigidly connected X­ray tube and detector, runs on an elliptical path around the facial skull. Thereby different rotation centers are controlled. Due to the different distances of the jaw sections to the X­ray tube and the image receiver, differencing velocities result and thus blurring effects as the basis of the layer or slice representation. Slit collimators lead to a narrow and continuous line-like representation of the different widths of the dental arch.


Assuntos
Radiografia Dentária/métodos , Radiografia Panorâmica , Humanos
2.
Dentomaxillofac Radiol ; 49(1): 20190107, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31386555

RESUMO

OBJECTIVES: To investigate the current clinical applications and diagnostic performance of artificial intelligence (AI) in dental and maxillofacial radiology (DMFR). METHODS: Studies using applications related to DMFR to develop or implement AI models were sought by searching five electronic databases and four selected core journals in the field of DMFR. The customized assessment criteria based on QUADAS-2 were adapted for quality analysis of the studies included. RESULTS: The initial electronic search yielded 1862 titles, and 50 studies were eventually included. Most studies focused on AI applications for an automated localization of cephalometric landmarks, diagnosis of osteoporosis, classification/segmentation of maxillofacial cysts and/or tumors, and identification of periodontitis/periapical disease. The performance of AI models varies among different algorithms. CONCLUSION: The AI models proposed in the studies included exhibited wide clinical applications in DMFR. Nevertheless, it is still necessary to further verify the reliability and applicability of the AI models prior to transferring these models into clinical practice.


Assuntos
Inteligência Artificial , Radiografia Dentária , Radiologia , Algoritmos , Inteligência Artificial/normas , Inteligência Artificial/tendências , Humanos , Radiografia Dentária/métodos , Radiografia Dentária/tendências , Reprodutibilidade dos Testes
3.
Medicine (Baltimore) ; 98(51): e17987, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31860950

RESUMO

INTRODUCTION: The odontogenic keratocyst (OKC), previously known as keratocystic odontogenic tumor has been the most disputable pathologies of the maxillofacial region. Patients with OKC are often asymptomatic but may present with pain, swelling, or discharge. Despite the aggressive nature, previous literature as early as 1970s reported the fact that parakeratinized OKC can be treated by means of marsupialization alone. PATIENTS CONCERNS: The patient had reported with a complaint of pain and swelling in relation with a tooth in mandibular right quadrant. DIAGNOSIS: This case report discusses features of a rare, extensive, panmandibular OKC that is only second of its kind mentioned in the literature. INTERVENTION: As a usual treatment protocol, marsupialization was attempted first. Immunohistochemical analysis revealed reduced expression of Ki-67 and B cell lymphoma 2 (bcl-2) markers after marsupialization from 2 separate sites. However, due to incomplete resolution in the lower right anterior region, an aggressive approach was taken by curetting it out surgically along with associated teeth and cortical plate followed by application of Carnoy's solution. OUTCOME: Postsurgery uneventful healing of the lesion was noted on regular follow-up visits with complete resolution at 40 months. The case has been followed for 10 years with no sign of relapse and reoccurrence. CONCLUSIONS: Based on the expression of markers it can thus be concluded that Ki-67 and bcl-2 are site specific and bear strong relationship with the recurrence of OKCs.


Assuntos
Doenças Mandibulares/diagnóstico por imagem , Doenças Mandibulares/cirurgia , Cistos Odontogênicos/diagnóstico por imagem , Cistos Odontogênicos/cirurgia , Radiografia Dentária/métodos , Adulto , Biópsia por Agulha , Dentística Operatória/métodos , Feminino , Seguimentos , Humanos , Imuno-Histoquímica , Doenças Mandibulares/patologia , Cistos Odontogênicos/patologia , Cuidados Pré-Operatórios/métodos , Doenças Raras , Medição de Risco , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do Tratamento
4.
Dentomaxillofac Radiol ; 48(7): 20180466, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31295019

RESUMO

OBJECTIVES: To evaluate bone repair of an osseous defect in a rat animal model through fractal analysis and radiopacity analysis in radiographic images. METHODS: 120 rats were subjected to extraction of their first molar and divided into four groups (n = 6/group) according to the material used for bone grafting: mineralized bovine bone, demineralized bovine bone (DBB), blood clot (BC - control) or Bio-Oss® (BO). The animals were sacrificed after 1, 7, 14, 21 and 49 days and subjected to radiographic evaluation. For fractal analysis (FA), a square regionof interest of 30 × 30 pixels was used, and radiopacity was measured as the mean gray scale (MGS) value for three points of 5 × 5 pixels in the apical, medial and coronal regions of the defect. Histomorphometric evaluation was realized as the gold standard for bone neo-formation and maturation of the new osseous matrix. RESULTS: Histomorphometric evaluation suggested that DBB showed faster mineralized deposition and resulted in more mature bone at the final time point of evaluation. Mineralized bovine bone and Bio-Oss presented similar results. The mineralized groups did not show significant differences in bone maturation. The radiopacity analysis revealed a significant difference (p < 0.05) between the DBB and blood clot groups at the final time point. FA did not show any significant differences at the final time point. CONCLUSIONS: Mean gray scale seemed to be more effective for the quantification of bone repair than FA in the demineralized group in this animal model. Results for the mineralized groups did not reveal a significant difference, leading to the conclusion that both methods are effective.


Assuntos
Materiais Biocompatíveis , Osso e Ossos , Fractais , Radiografia Dentária , Animais , Materiais Biocompatíveis/metabolismo , Osso e Ossos/diagnóstico por imagem , Bovinos , Modelos Animais , Osteogênese , Radiografia Dentária/métodos , Ratos , Cicatrização
5.
Dentomaxillofac Radiol ; 48(7): 20190014, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31237774

RESUMO

The objective of this paper is to provide recommendations towards the appropriate use of thyroid shielding in dental cone beam CT (CBCT). Based on current evidence of thyroid radiosensitivity, dosimetric data in the presence and absence of shielding, and a depiction of potential adverse effects of thyroid shielding, a concise set of recommendations was prepared. According to current risk models, thyroid sensitivity is particularly high at a young age, and much higher for females. In the literature, involving adult male, female and paediatric reference phantoms, the use of a tightly fitted thyroid collar with a lead-equivalent thickness of at least 0.25 mm has consistently shown a significant reduction (average: 45.9%) of the equivalent dose to the thyroid. It can therefore be recommended that thyroid shielding should be routinely used for children undergoing CBCT scanning and is recommended for adults up to the age of 50. The increase of the X-ray tube current from automatic exposure control systems due to thyroid shielding can be avoided by placing the shielding collar after acquiring the scout images. Should real-time tube current modulation be implemented in dental CBCT imaging in the future, perspectives regarding the appropriate use of shielding may change according to current trends in CT. In view of the manifestation of metal artefacts, shielding is best avoided if radiological evaluation of tissues below the lower border of the mandible is needed.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Proteção Radiológica , Radiografia Dentária/métodos , Glândula Tireoide , Adolescente , Adulto , Criança , Pré-Escolar , Tomografia Computadorizada de Feixe Cônico/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Doses de Radiação , Proteção Radiológica/métodos , Dosimetria Termoluminescente , Adulto Jovem
6.
Dentomaxillofac Radiol ; 48(7): 20190036, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31188678

RESUMO

OBJECTIVES: To evaluate the effects of syngo WARP on reducing metal artefacts from dental materials. METHODS: Short tau inversion recovery (STIR) with syngo WARP [a dedicated metal artefact reduction sequence in combination with view-angle-tilting (VAT)] was performed using phantoms of three dental alloys: cobalt-chromium (Co-Cr), nickel-chromium (Ni-Cr), and titanium (Ti). Artefact volumes and reduction ratios of black, white and overall artefacts in the standard STIR and syngo WARP images with several different parameter settings were quantified according to standards of the American Society for Testing and Materials F2119-07. In all sequences, the artefact volumes and reduction ratios were compared. The modulation transfer function (MTF) and contrast-to-noise ratio (CNR) were also measured for evaluation of image quality. RESULTS: In standard STIR, the overall artefact volume of Co-Cr was markedly larger than those of Ni-Cr and Ti. All types of artefacts tended to be reduced with increasing receiver bandwidth (rBW) and VAT. The effect of artefact reduction tended to be more obvious in the axial plane than in the sagittal plane. Compared with standard STIR, syngo WARP with a matrix of 384 × 384, receiver bandwidth of 620 Hz/pixel, and VAT of 100 % in the axial plane obtained reduction effects of 30 % (white artefacts), 45 % (black artefacts), and 38 % (overall artefacts) although MTF and CNR decreased by 30 and 22 % compared with those of standard STIR, respectively. CONCLUSIONS: syngo WARP for STIR can effectively reduce metal artefacts from dental materials.


Assuntos
Artefatos , Ligas Dentárias , Radiografia Dentária , Ligas Dentárias/química , Aumento da Imagem , Imagem por Ressonância Magnética , Imagens de Fantasmas , Radiografia Dentária/métodos
7.
J Med Syst ; 43(6): 148, 2019 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-31011883

RESUMO

Osteoporosis detection at earlier stages can enhance the life span of an elderly individual. The aim of the study is to perform semi-automated measurement of mandibular cortical thickness (MCT) on a dental panoramic radiograph (DPR) and thereby to predict the risk of low BMD among the studied population. The study involved 76 women (mean age: 57.2 ± 12.6 years). The DPR was obtained using KODAK 8000C system. The BMD of right total hip (T-BMD) was obtained using DPX Prodigy Dual-energy X-ray absorptiometry (DXA) Scanner. The DPR obtained were subjected to image processing techniques to perform MCT measurement. The region of interest was manually selected around the mental foramen and enhanced using a median filter. The Ostu segmentation was performed and connected component labelling operation was performed to determine the lower boundary by finding the contour with maximum area. Subsequently, the haar wavelet operation was carried out to find the magnitude and thereby select the upper delineating cortical boundary. The Pearson test results revealed (r = 0.96, p < 0.01) for the standard (manual) MCT measurement against the MCT measured using the proposed semi-automated scheme. ROC analysis revealed that MCT = 2.5 mm could be an optimal threshold in spotting individuals at risk of low BMD. The results of the study revealed that the MCT measured on a DPR using the proposed approach could be helpful for identifying individuals at risk of low BMD.


Assuntos
Densidade Óssea/fisiologia , Diagnóstico por Computador/métodos , Mandíbula/diagnóstico por imagem , Osteoporose Pós-Menopausa/diagnóstico , Radiografia Dentária/métodos , Absorciometria de Fóton , Adulto , Idoso , Feminino , Humanos , Mandíbula/patologia , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/diagnóstico por imagem , Curva ROC , Análise de Ondaletas
8.
Clin Oral Investig ; 23(6): 2573-2581, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31025192

RESUMO

OBJECTIVES: A narrative review on the potential use of low-dose protocols for cone beam computed tomography (CBCT) was conducted to identify indications and their relevance for various dental disciplines. MATERIALS AND METHODS: Google Scholar was searched using the words "low-dose CBCT". Reviews, consensus papers, clinical studies, and experimental studies were eligible for the initial screening process, but for data extraction only original articles were selected. Similar search procedures were then performed with the additional search words "pedo," "ortho," "endo," "implant," "perio," and "oral surgery." Furthermore, references of included articles were examined to identify further relevant articles. RESULTS: After screening, 27 publications remained for the data extraction process. Low-dose protocols have been reported for specialties such as pediatric dentistry (evaluating orofacial clefts, periapical lesions, impacted teeth, and autotransplantation), orthodontics (cephalometric analysis and interim assessment of treatment results), endodontics (detecting root fractures, resorptions and periapical bone loss), implant dentistry (planning implant insertion, evaluating peri-implant fenestration and dehiscence), periodontology (assessing periodontal structures), and oral and maxillofacial surgery (assessing mandibular third molars and TMJs). Nevertheless, most of the literature available is related to non-clinical studies. Furthermore, there is a lack of position statements or guidelines from authoritative bodies regarding the use of low-dose protocols in dental medicine. CONCLUSIONS: Low-dose protocols for CBCT imaging seem to have potential in various disciplines in dental medicine ranging from pediatric dentistry to oral and maxillofacial surgery. Dose reduction is usually achieved by mAs reduction, use of partial rotations, reduced number of projections, and larger voxel sizes, but seldom by kV reduction. CLINICAL RELEVANCE: Albeit low-dose protocols have potential to result in a reduction of dose exposure for 3D imaging due to dental indications, there is a need to more clearly specify indications and limitations to avoid indiscriminate use of standard and high-dose CBCT scans in the future on the lines of ALARA/ALADA principles.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Doses de Radiação , Radiografia Dentária/métodos , Humanos
9.
Av. odontoestomatol ; 35(2): 73-82, mar.-abr. 2019. ilus
Artigo em Espanhol | IBECS | ID: ibc-184311

RESUMO

Introducción: La radiología oral y maxilofacial (RMF) es la disciplina encargada del uso de rayos X y otros tipos de radiación para el diagnóstico de enfermedades y condiciones del área maxilofacial. El propósito de la presente revisión es analizar el aporte de la RMF al diagnóstico clínico. Revisión: Las legislaciones nacionales suelen establecer requisitos para autorizar el uso e instalación de equipos generadores de radiaciones ionizantes, sin embargo, falta regulación sobre la responsabilidad del diagnóstico radiográfico. Por esto, es necesario aplicar consideraciones éticas y principios de protección radiológica que garanticen el uso responsable de los exámenes radiográficos. Debiera existir una persona responsable del diagnóstico radiográfico, que debe ser un odontólogo con conocimientos en interpretación radiográfica y cursos de educación continua en RMF. La solicitud y toma radiográfica son acciones fundamentales que contribuyen a que el responsable del diagnóstico radiográfico realice uno correcto. La RMF actualmente es reconocida como especialidad en más de 50 países, sin embargo, existe la necesidad de reconocimiento en otros países. Debido a su formación profesional, la existencia de especialistas en RMF contribuye a mejores diagnósticos radiográficos, con el consecuente impacto en el diagnóstico clínico y tratamiento del paciente. Conclusiones: La RMF es una disciplina fundamental para determinar el diagnóstico clínico del paciente. Para que los exámenes radiográficos usados aporten al clínico tratante a brindar la mejor atención al paciente, es fundamental que estos exámenes cuenten con un correcto y completo diagnóstico realizado por un profesional con entrenamiento y conocimientos en RMF, idealmente especialista en RMF


Introduction: Oral and maxillofacial radiology (MFR) is the discipline that deals with the use of X-rays and other kinds of radiation for the diagnosis of diseases and conditions of the maxillofacial region. The aim of the present review is to analyze the contribution of MFR to the clinical diagnosis. Review: National laws usually establish the requirements to authorize the use and installation of ionizing radiation generating equipment, nevertheless, there is a lack of regulation regarding the responsibility of the radiographic diagnosis. Because of this, it is necessary to apply ethical considerations and principles of radiation protection to guarantee the responsible use of the radiographic examinations. There should be a person responsible of the radiographic diagnosis, who must be a dentist with knowledge in radiographic interpretation and with continuing education courses in MFR. The radiographic request and taking are fundamental actions that contribute the responsible of radiographic diagnosis to elaborates a correct diagnosis. Nowadays, MFR is recognized as a specialty in more than 50 countries, however, there is a need of its acknowledgment in other countries. Due to the MFR specialist training, his/her existence contributes to a better radiographic diagnosis, with the consequent impact on clinical diagnosis and patient treatment. Conclusions: MFR is a fundamental discipline for determining the clinical diagnosis of the patient. In order the radiographic exams contribute the treating clinician to offer the best clinical attention to the patient, it is fundamental these exams have a correct and complete radiographic diagnosis, performed by a professional with training and knowledge in MFR, ideally an MFR specialist


Assuntos
Humanos , Diagnóstico Clínico/tendências , Radiografia Dentária/instrumentação , Radiografia Panorâmica/instrumentação , Radiografia Dentária/métodos , Radiografia Panorâmica/métodos , Ortodontia Corretiva/métodos
10.
Oncology ; 96(4): 173-178, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30836369

RESUMO

Firstly used in the early 90s to generate 3-dimensional projections of X-ray images, cone beam computed tomography (CBCT) has resulted in a large application in dentomaxillofacial imaging, even in children. CBCT uses ionizing radiation that may cause damage to the DNA, and children are at the greatest carcinogenesis risk due to their higher tissue radiosensitivity and their longer life expectancy compared to adults. The questions of whether the cancer risk is really increased after repeated dental CBCT in childhood and of what the underlying biological basis is have become hot topics in the field of dentistry and radiobiology. We performed an overview of the current literature to assess an acceptable role of CBCT in pediatric dentistry.


Assuntos
Tomografia Computadorizada de Feixe Cônico/efeitos adversos , Dano ao DNA , Neoplasias Induzidas por Radiação/etiologia , Odontopediatria , Exposição à Radiação/efeitos adversos , Radiografia Dentária/efeitos adversos , Fatores Etários , Humanos , Neoplasias Induzidas por Radiação/diagnóstico , Neoplasias Induzidas por Radiação/genética , Odontopediatria/métodos , Radiografia Dentária/métodos , Medição de Risco , Fatores de Risco , Fatores de Tempo
11.
Radiologia ; 61(3): 225-233, 2019.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-30827491

RESUMO

BACKGROUND AND OBJECTIVE: There is a lack of quantitative measures of the quality of alveolar trabecular bone, an important factor in implantology. This study aimed to develop a method of objectively assessing the quality of trabecular bone by means of image processing and structural analysis of multidetector computed tomography images and to establish differences between tooth types and tooth presence/absence. MATERIALS AND METHODS: We analyzed 20 patients who underwent multidetector computed tomography to evaluate mandibular bone and tooth positioning. Image analysis included automatic segmentation of the mandible, obtainment of sections perpendicular to the dental arch, and structural analysis of the trabecular bone in each section. We calculated the ratio between the volume of bone and the total volume of the section, the thickness, the trabecular number, and the mean attenuation in Hounsfield units. We analyzed the differences among different tooth types (incisors, canines, premolars, and molars) and between present and absent teeth. RESULTS: We found statistically significant differences between different tooth types and between sections in which teeth were present or absent. Incisors had a greater ratio of trabecular bone; the ratio of trabecular bone progressively decreased from the incisors to the canines, premolars, and molars. The ratio of trabecular bone was greater in sections in which teeth were absent than in those in which teeth were present. CONCLUSIONS: The method allows to quantify the structural properties of alveolar bone from multidetector computed tomography images. Our results provide an objective picture of the bone substrate that can be useful for planning and following up dental implant procedures.


Assuntos
Processo Alveolar/diagnóstico por imagem , Arco Dental/diagnóstico por imagem , Tomografia Computadorizada Multidetectores/métodos , Radiografia Dentária/métodos , Adulto , Processo Alveolar/anatomia & histologia , Análise de Variância , Arco Dental/anatomia & histologia , Feminino , Humanos , Masculino , Radiografia Panorâmica/métodos , Estudos Retrospectivos , Dente/diagnóstico por imagem , Perda de Dente/diagnóstico por imagem
12.
J Endod ; 45(4): 402-405, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30770280

RESUMO

INTRODUCTION: Currently, the success of periapical microsurgery is determined by the restoration of the lamina dura and the elimination of symptoms. However, inadequate site preservation may prevent later implant placement. Although not possible before, the advent of cone-beam computed tomographic imaging and computer-aided registration allows for indirect and accurate 3-dimensional analysis of the surgical site over time. This study analyzed the volumetric healing pattern of the buccal plate after periapical microsurgery, with a specific focus on the buccolingual thickness of bone and the regression of the surface contour of the cortical plate. METHODS: Thirty-seven patients were scheduled for follow-up at least 1 year after periapical microsurgery (median = 25 months, total range = 12-31 months). Volumetric healing was analyzed by converting preoperative and postoperative cone-beam computed tomographic images into digital 3-dimensional models. The models were then registered to be able to analyze the changes in volume over time. Analysis was completed using Geomagic software (3D Systems, Rock Hill, SC), which allowed for registration of the volumes, calculation of volume change, and calculation of the margin of error. RESULTS: Twelve cases qualified for volumetric analysis. The median volumetric reduction of the cortical plate was -24.9 mm3 (interquartile range = -8.94 to -67 mm3), with an average linear error of 0.7 mm. This corresponded to an average loss in buccolingual dimension of 0.1-0.25 mm. Regression of the cortical plate was within the margin of error in all cases. CONCLUSIONS: After periapical microsurgery, and in the absence of grafting materials or membranes, healing occurs with little to no regression of the buccal cortical plate.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Imagem Tridimensional/métodos , Maxila/diagnóstico por imagem , Microcirurgia/métodos , Doenças Periapicais/diagnóstico por imagem , Doenças Periapicais/cirurgia , Radiografia Dentária/métodos , Cicatrização , Adolescente , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Maxila/anatomia & histologia , Maxila/fisiopatologia , Pessoa de Meia-Idade , Doenças Periapicais/fisiopatologia , Fatores de Tempo , Adulto Jovem
13.
J Indian Soc Pedod Prev Dent ; 37(1): 80-86, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30804312

RESUMO

Objective: Pediatric endodontics has witnessed many advances in recent years, thus facilitating a faster and efficient treatment option in root canal therapy in children. This in vitro evaluation aims to determine the amount of dentin removal in primary mandibular first and second molars instrumented with hand and rotary files using cone-beam computed tomography (CBCT). Materials and Method: Sixty primary mandibular molars were divided into two groups: Group I was prepared by manual instrumentation using K-type files and Group II was prepared with rotary instrumentation using 0.04 Hero Shaper Classics. Both these groups were further divided into two subgroups, namely (a) primary mandibular first molar and (b) primary mandibular second molar. All the root canals were prepared up to size 30 using the stepback technique. They were mounted on silicone-based impression material and subjected to CBCT scans for the evaluation of dentin removal before and after instrumentation. Dentin removal was calculated by superimposing images using the InVivo 5.1 Anatomage software. Data were statistically analyzed using independent samples t- test. Results: An average amount of dentin removed was found to be significantly higher in manual instrumentation compared to rotary instrumentation in both primary mandibular first and second molars (P < 0.001). Conclusions: Rotary technique serves as an efficient alternative to the traditional manual instrumentation by overcoming its shortcomings in terms of conservation of the remaining dentin thickness and the time required for its preparation.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Dentina/cirurgia , Dente Molar/cirurgia , Radiografia Dentária/métodos , Preparo de Canal Radicular/instrumentação , Humanos , Técnicas In Vitro , Dente Molar/diagnóstico por imagem , Preparo de Canal Radicular/métodos , Dente Decíduo/cirurgia
14.
Med Phys ; 46(4): 1686-1696, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30697765

RESUMO

PURPOSE: In recent years, health risks concerning high-dose x-ray radiation have become a major concern in dental computed tomography (CT) examinations. Therefore, adopting low-dose computed tomography (LDCT) technology has become a major focus in the CT imaging field. One of these LDCT technologies is downsampling data acquisition during low-dose x-ray imaging processes. However, reducing the radiation dose can adversely affect CT image quality by introducing noise and artifacts in the resultant image that can compromise diagnostic information. In this paper, we propose an artifact correction method for downsampling CT reconstruction based on deep learning. METHOD: We used clinical dental CT data with low-dose artifacts reconstructed by conventional filtered back projection (FBP) as inputs to a deep neural network and corresponding high-quality labeled normal-dose CT data during training. We trained a generative adversarial network (GAN) with Wasserstein distance (WGAN) and mean squared error (MSE) loss, called m-WGAN, to remove artifacts and obtain high-quality CT dental images in a clinical dental CT examination environment. RESULTS: The experimental results confirmed that the proposed algorithm effectively removes low-dose artifacts from dental CT scans. In addition, we showed that the proposed method is efficient for removing noise from low-dose CT scan images compared to existing approaches. We compared the performances of the general GAN, convolutional neural networks, and m-WGAN. Through quantitative and qualitative analysis of the results, we concluded that the proposed m-WGAN method resulted in better artifact correction performance preserving the texture in dental CT scanning. CONCLUSIONS: The image quality evaluation metrics indicated that the proposed method effectively improves image quality when used as a postprocessing technique for dental CT images. To the best of our knowledge, this work is the first deep learning architecture used with a commercial cone-beam dental CT scanner. The artifact correction performance was rigorously evaluated and demonstrated to be effective. Therefore, we believe that the proposed algorithm represents a new direction in the research area of low-dose dental CT artifact correction.


Assuntos
Algoritmos , Odontologia , Processamento de Imagem Assistida por Computador/métodos , Radiografia Dentária/métodos , Tomografia Computadorizada por Raios X/métodos , Artefatos , Humanos , Doses de Radiação , Razão Sinal-Ruído
16.
Health Phys ; 116(2): 163-169, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30585958

RESUMO

Diagnostic imaging is essential in dentistry. Doses range from low to very low, benefits to patients can be immense, and safe techniques are well known but widely ignored. Doses range from very low with properly executed intraoral, cephalometric, and panoramic imaging to higher than multidetector computed tomography with cone-beam computed tomography. Benefits are substantial: imaged dental disease, often obscured from direct vision by size and anatomy, can pose a mortal threat to the patient. Additionally, imaging is often central in planning complex dental procedures. Safe imaging in dental environments is straightforward; the means for minimizing dose and maximizing diagnostic efficacy have been widely and inexpensively available for decades. Such techniques reduce patient dose by some 80% over traditional techniques but are infrequently used. Digital panoramic equipment reduces doses markedly. For cone-beam computed tomography imaging, selection criteria are critical in defining appropriate fields of view and presets; several publications address this. It is treacherous to discuss risk in oral and maxillofacial radiology. There are more than 330 million dental x-ray examinations annually, the majority being intraoral examinations, with steady increases in panoramic and cone-beam computed tomography. Radiation carcinogenesis from conventional imaging is unlikely, while large field-of-view, high-resolution preset cone-beam computed tomography can be comparable in carcinogenesis risk to craniofacial multidetector computed tomography. Uncertainties in risk estimation from low doses coupled with the huge numbers of dental images taken annually and the rapid growth of cone-beam computed tomography dictate that safe oral and maxillofacial imaging is in the interests of patients, staff, and the public. As low as reasonably achievable (ALARA) practices and linear no-threshold risk modeling continue to be prudent and appropriate.


Assuntos
Segurança do Paciente , Radiografia Dentária , Tomografia Computadorizada de Feixe Cônico , Humanos , Tomografia Computadorizada Multidetectores , Procedimentos Cirúrgicos Bucais , Doses de Radiação , Radiografia Dentária/efeitos adversos , Radiografia Dentária/métodos , Radiografia Dentária Digital , Radiografia Panorâmica , Medição de Risco , Doenças Estomatognáticas/diagnóstico por imagem
18.
Eur J Orthod ; 41(1): 67-79, 2019 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-29771300

RESUMO

Background: Orthodontically induced external root resorption (OIRR) is a pathologic consequence of orthodontic tooth movement. However, the limitations of two-dimensional radiography suggest that cone beam computed tomography (CBCT) with its three-dimensional capabilities might be more suitable to assess OIRR. Objective: The aim of this study was to assess in an evidence-based manner data on linear or volumetric OIRR measurements of permanent teeth by means of CBCT, during and/or after the end of orthodontic treatment. Search methods: Unrestricted electronic and hand searches were performed up to January 2017 in 15 databases. Selection criteria methods: Randomized clinical trials, prospective, and retrospective non-randomized studies assessing OIRR during and/or after orthodontic treatment using CBCT in human patients were included. Data collection and analysis: After duplicate study selection, data extraction, and risk-of-bias assessment according to the Cochrane guidelines, random-effects meta-analyses, followed by subgroup, meta-regression, and sensitivity analyses were also performed in order to evaluate factors that affect OIRR. Results: A total of 33 studies (30 datasets) were included in the qualitative analysis while data from 27 of them were included in the quantitative analysis. Direct comparisons from randomized trials found little to no influence of appliance-related factors on OIRR. Explorative analyses including non-randomized studies found a pooled OIRR of 0.79 mm based on all included studies and 0.86 mm when OIRR was assessed at the end of orthodontic treatment. Statistically significant differences in OIRR were found according to tooth type or jaw, inclusion of extractions, treatment duration, and diagnostic accuracy of the CBCT. Conclusions: Based on the results of this study, CBCT seems to be a reliable tool to examine OIRR during or at the end of orthodontic treatment. Although the average OIRR measured with CBCT seems to lack clinical relevance, there are certain factors that may affect OIRR following orthodontic treatment. Nevertheless, due to data heterogeneity and low quality of the included studies, the corresponding results should be interpreted with some caution. Registration: PROSPERO (CRD42016030131).


Assuntos
Reabsorção da Raiz/etiologia , Técnicas de Movimentação Dentária/efeitos adversos , Tomografia Computadorizada de Feixe Cônico/métodos , Humanos , Radiografia Dentária/métodos , Reabsorção da Raiz/diagnóstico por imagem
19.
Acta Odontol Scand ; 77(2): 107-113, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30345847

RESUMO

OBJECTIVE: The aim of this study was to investigate the possibility of evaluating the relationship between dental maturation and skeletal maturation without taking a hand-wrist radiogram outside of panoramic radiogram. MATERIALS AND METHODS: Panoramic and hand-wrist radiographs of 717 patients (383 girls and 334 boys), with ages ranging from 10 to 15 years, were evaluated. Dental maturity stages of the mandibular canine, first premolar, second premolar and second molar teeth were determined by Demirjian's and Nolla's methods. The skeletal maturation was determined by Fishman method and bone age was determined through the Greulich and Pyle method. RESULTS: All teeth showed positive and statistically significant correlations, the highest correlation was between the mandibular second premolar calcification stages and hand-wrist maturation stages. According to both dental age determination methods, mandibular second premolar was prominent in determining to the pubertal growth stages. CONCLUSIONS: There was a positive relationship between dental calcification stages and skeletal maturation stages, in the study population. Dental calcification stages of the second mandibular premolar showed the highest positive correlation with the skeletal maturation stages.


Assuntos
Determinação da Idade pelos Dentes/métodos , Desenvolvimento Ósseo/fisiologia , Radiografia Dentária/métodos , Calcificação de Dente/fisiologia , Dente/crescimento & desenvolvimento , Adolescente , Dente Pré-Molar/diagnóstico por imagem , Calcificação Fisiológica/fisiologia , Criança , Feminino , Humanos , Masculino , Radiografia Panorâmica , Fatores Sexuais , Dente/diagnóstico por imagem , Turquia
20.
J Investig Clin Dent ; 10(1): e12378, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30474243

RESUMO

AIM: The aim of the present study was to evaluate the efficacy on the healing of mechanical decontamination of infected implant surfaces performed with a titanium brush. METHODS: Mandibular premolars and first molars were extracted bilaterally in six dogs. After 3 months, two unsubmerged implants were installed on both sides of the mandible. Three months later, peri-implantitis was induced with ligatures for 3 months and then removed. After 1 month, surgical mechanical decontamination of the surfaces was performed either with a rotatory titanium brush or gauzes soaked in saline. Five month later, biopsies were retrieved. Evaluations on X-rays taken of the mesiodistal plane and on histological slides prepared in a buccal-lingual plane were performed. RESULTS: After the induction of peri-implantitis, a mean marginal bone loss of 2.6 ± 0.6 mm and 1.9 ± 1.0 mm was observed in the brush and gauze groups by X-ray, respectively. Five months after treatment, a mean gain of marginal bone of 0.6 mm was obtained in both groups. The mean closures of the vertical and horizontal defects were 0.6 mm and 0.6 mm for the brush group, and 0.8 mm and 0.5 mm for the gauze group, respectively. Histologically, a loss of attachment at the buccal aspect of 2.2 ± 0.9 mm in the brush group and of 2.3 ± 0.5 mm in the gauze group was found. No statistically-significant differences were found after the treatment. CONCLUSIONS: Mechanical implant surface decontamination performed with a rotatory titanium brush resulted in a marginal bone level gain, yielding a low content of inflammatory infiltrate close to the marginal bone.


Assuntos
Descontaminação/métodos , Peri-Implantite/diagnóstico por imagem , Peri-Implantite/patologia , Peri-Implantite/terapia , Perda do Osso Alveolar/diagnóstico por imagem , Perda do Osso Alveolar/patologia , Perda do Osso Alveolar/terapia , Animais , Dente Pré-Molar/patologia , Descontaminação/instrumentação , Implantação Dentária Endo-Óssea/efeitos adversos , Implantes Dentários/efeitos adversos , Placa Dentária , Planejamento de Prótese Dentária , Modelos Animais de Doenças , Cães , Implantes Experimentais/efeitos adversos , Mandíbula/patologia , Mandíbula/cirurgia , Peri-Implantite/cirurgia , Radiografia Dentária/métodos , Propriedades de Superfície , Titânio
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