Applications of artificial intelligence in dentistry: A comprehensive review

This work was funded by the Spanish Ministry of Sciences, Innovation and Universities under Projects RTI2018-101674-B-I00 and PGC2018-101904-A-100, University of Granada project A.TEP. 280.UGR18, I+D+I Junta de Andalucia 2020 project P20-00200, and Fapergs/Capes do Brasil grant 19/25510000928-3. Funding for open-access charge: Universidad de Granada/CBUAObjective: To perform a comprehensive review of the use of artificial intelligence (AI) and machine learning (ML) in dentistry, providing the community with a broad insight on the different advances that these technologies and tools have produced, paying special attention to the area of esthetic dentistry and color research. Materials and methods: The comprehensive review was conducted in MEDLINE/ PubMed, Web of Science, and Scopus databases, for papers published in English language in the last 20 years. Results: Out of 3871 eligible papers, 120 were included for final appraisal. Study methodologies included deep learning (DL; n = 76), fuzzy logic (FL; n = 12), and other ML techniques (n = 32), which were mainly applied to disease identification, image segmentation, image correction, and biomimetic color analysis and modeling. Conclusions: The insight provided by the present work has reported outstanding results in the design of high-performance decision support systems for the aforementioned areas. The future of digital dentistry goes through the design of integrated approaches providing personalized treatments to patients. In addition, esthetic dentistry can benefit from those advances by developing models allowing a complete characterization of tooth color, enhancing the accuracy of dental restorations. Clinical significance: The use of AI and ML has an increasing impact on the dental profession and is complementing the development of digital technologies and tools, with a wide application in treatment planning and esthetic dentistry procedures.Spanish Ministry of Sciences, Innovation and Universities RTI2018-101674-B-I00 PGC2018-101904-A-100University of Granada project A.TEP. 280.UGR18Junta de Andalucia P20-00200Fapergs/Capes do Brasil grant 19/25510000928-3Universidad de Granada/CBU

Machine Learning in Dentistry: A Scoping Review

Machine learning (ML) is being increasingly employed in dental research and application. We aimed to systematically compile studies using ML in dentistry and assess their methodological quality, including the risk of bias and reporting standards. We evaluated studies employing ML in dentistry published from 1 January 2015 to 31 May 2021 on MEDLINE, IEEE Xplore, and arXiv. We assessed publication trends and the distribution of ML tasks (classification, object detection, semantic segmentation, instance segmentation, and generation) in different clinical fields. We appraised the risk of bias and adherence to reporting standards, using the QUADAS-2 and TRIPOD checklists, respectively. Out of 183 identified studies, 168 were included, focusing on various ML tasks and employing a broad range of ML models, input data, data sources, strategies to generate reference tests, and performance metrics. Classification tasks were most common. Forty-two different metrics were used to evaluate model performances, with accuracy, sensitivity, precision, and intersection-over-union being the most common. We observed considerable risk of bias and moderate adherence to reporting standards which hampers replication of results. A minimum (core) set of outcome and outcome metrics is necessary to facilitate comparisons across studies

Automatic dental caries detection in bitewing radiographs.

Doctoral Degree. University of KwaZulu-Natal, Durban.Dental Caries is one of the most prevalent chronic disease around the globe. Distinguishing carious lesions has been a challenging task. Conventional computer aided diagnosis and detection methods in the past have heavily relied on visual inspection of teeth. These are only effective on large and clearly visible caries on affected teeth. Conventional methods have been limited in performance due to the complex visual characteristics of dental caries images, which consists of hidden or inaccessible lesions. Early detection of dental caries is an important determinant for treatment and benefits much from the introduction of new tools such as dental radiography. A method for the segmentation of teeth in bitewing X-rays is presented in this thesis, as well as a method for the detection of dental caries on X-ray images using a supervised model. The diagnostic method proposed uses an assessment protocol that is evaluated according to a set of identifiers obtained from a learning model. The proposed technique automatically detects hidden and inaccessible dental caries lesions in bitewing radio graphs. The approach employed data augmentation to increase the number of images in the data set in order to have a total of 11,114 dental images. Image pre-processing on the data set was through the use of Gaussian blur filters. Image segmentation was handled through thresholding, erosion and dilation morphology, while image boundary detection was achieved through active contours method. Furthermore, the deep learning based network through the sequential model in Keras extracts features from the images through blob detection. Finally, a convexity threshold value of 0.9 is introduced to aid in the classification of caries as either present or not present. The relative efficacy of the supervised model in diagnosing dental caries when compared to current systems is indicated by the results detailed in this thesis. The proposed model achieved a 97% correct diagnostic which proved quite competitive with existing models.Author's Publications are listed on page 4 of this thesis

Microfluidics for Biosensing

There are 12 papers published with 8 research articles, 3 review articles and 1 perspective. The topics cover: Biomedical microfluidics Lab-on-a-chip Miniaturized systems for chemistry and life science (MicroTAS) Biosensor development and characteristics Imaging and other detection technologies Imaging and signal processing Point-of-care testing microdevices Food and water quality testing and control We hope this collection could promote the development of microfluidics and point-of-care testing (POCT) devices for biosensing

New Insights on Biofilm Antimicrobial Strategies

Over the last few decades, the study of microbial biofilms has been gaining interest among the scientific community. These microbial communities comprise cells adhered to surfaces that are surrounded by a self-produced exopolymeric matrix that protects biofilm cells against different external stresses. Biofilms can have a negative impact on different sectors within society, namely in agriculture, food industries, and veterinary and human health. As a consequence of their metabolic state and matrix protection, biofilm cells are very difficult to tackle with antibiotics or chemical disinfectants. Due to this problem, recent advances in the development of antibiotic alternatives or complementary strategies to prevent or control biofilms have been reported. This book includes different strategies to prevent biofilm formation or to control biofilm development and includes full research articles, reviews, a communication, and a perspective

Interaction of environmental calcium/phosphate and pH with glass ionomer restoratives

Ph.DDOCTOR OF PHILOSOPH

In vitro caries: dental plaque formation and acidogenicity

Dental caries is a significant disease world-wide and although a massive reduction in prevalence has occurred over the past 50 years, incidents of this disease persist (particularly on the occlusal or aproximal surfaces and concerning younger demographics). The main reason for the observed reduction is exposure to fluoride either though water fluoridation and delivery by dentifrice. Environmental exposure reduces incidence by incorporation into the mineral phase of the hard tissue and, as a result, increases the resistance of the enamel mineral to acid-induced demineralisation. Several mechanisms have been proposed in an attempt to explain the caries-inhibiting effects of fluoride however its influence on the balance between de- and re-mineralisation episodes appears to be the principal route by which fluorides exert their effects. Efforts geared towards the continual improvement of fluoride delivery systems have also been successful to some extent and thus further exploration shows promise of improving the anticaries efficacy further. However, a complication is met in that, in vivo, multiple factors interrelated and consequently, differences in the consortia within natural oral biofilms combined with unavoidable inter-individual variations confound clinical investigations and make the distinction between relevant aspects of the process difficult. One possible alternative strategy is the development of in vitro biological models to simulate this process to a point of reflecting the in vivo situation whilst retaining control over the parameters which are known to be crucial to the progression of the disease. To this end, the Constant-Depth Film Fermenter (CDFF) has emerged as powerful tool to potentially meet the needs of current in vitro research. However, due to the lack of an inter-disciplinary approach to multi-faceted disease process, the full potential of the CDFF has not yet been reached. Therefore, the CDFF model was applied to study of anti-caries strategies which aimed to increase the persistence of the fluorides within natural microcosm biofilms. Enamel lesions were successfully produced within this system and, using a combination of both biological and non-biological demineralisations systems, the effects of anticaries agents (calcium and fluoride) were also investigated for their effects on lesion progression or reversal. Sodium fluoride (NaF; 300 ppm F-) exposures exhibited an ambiguous response on the microbial community although definite anticaries activity. Conversely, calcium lactate pre-rinses (Ca-lactate; 100 mM) appears to possess some inhibitory activity on the biofilms produced within the model whereas a less effective anticaries activity was observed in comparison to NaF exposures alone. Thus, further investigation of the effects of Ca-lactate should be pursued. Operation of the CDFF was also further developed to meet the needs of this study and analyses were performed on an integrative basis in order to capture the physiochemical events which take place during caries lesion formation. Microcosm plaques were shown to be highly diverse with respect to their community although homology was found on the bias of their ultimate definition, cariogenicity. The synthesis of inorganic mineral reservoirs within microcosm biofilms holds great potential for augmenting the physiology of the plaque and for increasing the efficacy of fluorides for prevention of enamel demineralisation. Microcosm biofilms may also have an adaptive capacity which could result in predicable response patterns. Ultimately, a holistic approach to the study of caries within a biological context provides greater insight into the caries process than approaches which lack specific interactions for the purposes of assigning direct relationships. With the successful development of a fully functional enamel caries model, the possibilities are endless

Hybridization of machine learning for advanced manufacturing

Tesis por compendio de publicacioines[ES] En el contexto de la industria, hoy por hoy, los términos “Fabricación Avanzada”, “Industria 4.0” y “Fábrica Inteligente” están convirtiéndose en una realidad. Las empresas industriales buscan ser más competitivas, ya sea en costes, tiempo, consumo de materias primas, energía, etc. Se busca ser eficiente en todos los ámbitos y además ser sostenible. El futuro de muchas compañías depende de su grado de adaptación a los cambios y su capacidad de innovación. Los consumidores son cada vez más exigentes, buscando productos personalizados y específicos con alta calidad, a un bajo coste y no contaminantes. Por todo ello, las empresas industriales implantan innovaciones tecnológicas para conseguirlo. Entre estas innovaciones tecnológicas están la ya mencionada Fabricación Avanzada (Advanced Manufacturing) y el Machine Learning (ML). En estos campos se enmarca el presente trabajo de investigación, en el que se han concebido y aplicado soluciones inteligentes híbridas que combinan diversas técnicas de ML para resolver problemas en el campo de la industria manufacturera. Se han aplicado técnicas inteligentes tales como Redes Neuronales Artificiales (RNA), algoritmos genéticos multiobjetivo, métodos proyeccionistas para la reducción de la dimensionalidad, técnicas de agrupamiento o clustering, etc. También se han utilizado técnicas de Identificación de Sistemas con el propósito de obtener el modelo matemático que representa mejor el sistema real bajo estudio. Se han hibridado diversas técnicas con el propósito de construir soluciones más robustas y fiables. Combinando técnicas de ML específicas se crean sistemas más complejos y con una mayor capacidad de representación/solución. Estos sistemas utilizan datos y el conocimiento sobre estos para resolver problemas. Las soluciones propuestas buscan solucionar problemas complejos del mundo real y de un amplio espectro, manejando aspectos como la incertidumbre, la falta de precisión, la alta dimensionalidad, etc. La presente tesis cubre varios casos de estudio reales, en los que se han aplicado diversas técnicas de ML a distintas problemáticas del campo de la industria manufacturera. Los casos de estudio reales de la industria en los que se ha trabajado, con cuatro conjuntos de datos diferentes, se corresponden con: • Proceso de fresado dental de alta precisión, de la empresa Estudio Previo SL. • Análisis de datos para el mantenimiento predictivo de una empresa del sector de la automoción, como es la multinacional Grupo Antolin. Adicionalmente se ha colaborado con el grupo de investigación GICAP de la Universidad de Burgos y con el centro tecnológico ITCL en los casos de estudio que forman parte de esta tesis y otros relacionados. Las diferentes hibridaciones de técnicas de ML desarrolladas han sido aplicadas y validadas con conjuntos de datos reales y originales, en colaboración con empresas industriales o centros de fresado, permitiendo resolver problemas actuales y complejos. De esta manera, el trabajo realizado no ha tenido sólo un enfoque teórico, sino que se ha aplicado de modo práctico permitiendo que las empresas industriales puedan mejorar sus procesos, ahorrar en costes y tiempo, contaminar menos, etc. Los satisfactorios resultados obtenidos apuntan hacia la utilidad y aportación que las técnicas de ML pueden realizar en el campo de la Fabricación Avanzada

Novel phosphate-based cements for clinical applications

This Thesis aims at the development of two novel families of inorganic phosphate cements with suitable characteristics for clinical applications in hard tissue regeneration or replacement. It is organized in two distinct parts. The first part focuses at the development of silicon-doped a-tricalcium phosphate and the subsequent preparation of a silicon-doped calcium phosphate cement for bone regeneration applications. For this purpose, silicon-doped a-tricalcium phosphate was synthesized by sintering a calcium-deficient hydroxyapatite at 1250ºC with different amounts of silicon oxide. The high temperature polymorph a-tricalcium phosphate was stabilized by the presence of silicon, which inhibited reversion of the b-a transformation, whereas in the Si-free a-tricalcium phosphate completely reverted to the b-polymorph. It was observed that the presence of Si did not alter the b-a transformation temperature. Both the Si-doped a-tricalcium phosphate and its Si-free counterpart were used as reactants in the formulation of calcium phosphate cements. While Si-doped a-tricalcium phosphate showed faster hydrolysis to calcium deficient hydroxyapatite, the composition, morphology and mechanical properties of both cements were similar upon completion of the reaction. When the samples were immersed in simulated body fluid, the Si-doped cement exhibited a faster deposition of an apatite layer on its surface than its Si-free counterpart, suggesting an enhanced bioactivity of the doped-cement. An in vitro cell culture study, in which osteoblast-like cells were exposed to a medium modified by the materials, showed a delay in cell proliferation and a stimulation of cell differentiation, the differentiation being more marked for the Si-containing cement. These results were attributed to the Ca depletion from the medium by both cements and to the continuous Si release detected for the Si-containing cement. The second part of this Thesis is focused on the development of a new family of inorganic phosphate-based cements for biomedical applications, namely magnesium phosphate cements. The magnesium phosphate cements have been extensively used in civil engineering due to their fast setting, early strength acquisition and adhesive properties, properties that can be also of use for biomedical applications. However, there are some aspects that should be improved before they can be used in the human body, namely their high exothermic setting reaction and the release of potentially harmful ammonium ions. Therefore, a new family of magnesium phosphate cements was explored as candidate biomaterials for hard tissue applications. These cements were prepared by mixing magnesium oxide with either sodium dihydrogen phosphate, ammonium dihydrogen phosphate or an equimolar mixture of both. The exothermia and the setting kinetics of the new cement formulations were tailored. The ammonium-containing magnesium phosphate cements resulted in struvite as the major reaction product, whereas the magnesium phosphate cement prepared with sodium dihydrogen phosphate resulted in an amorphous product. The magnesium phosphate cements studied showed an early compressive strength substantially higher than that of conventional apatitic calcium phosphate cements. Moreover, they showed antimicrobial properties against bacteria present in dental infections, which were attributed to the synergistic effect of a high osmolarity and high pH of the cement extracts. These properties make magnesium phosphate cements good candidates for endodontic applications. It is with this latter point in mind that some of the most relevant physico-chemical properties were further optimized and characterized. Particularly, their radiopacity was enhanced by the addition of bismuth oxide. The sealing efficiency of the magnesium phosphate cements and their adhesion to dentin were shown to be comparable or even higher than those presented by other inorganic cements used for endodontic treatments.Aquesta Tesi té com a objectiu el desenvolupament de dues noves famílies de ciments inorgànics de base fosfat amb propietats adequades per a aplicacions clíniques en regeneració o substitució de teixits durs. La Tesi està organitzada en dues parts. La primera part està centrada en el desenvolupament de fosfat tricàlcic a dopat amb silici i la subseqüent preparació de ciments de fosfat de calci dopats amb silici. Per a aquest objectiu, es va obtenir fosfat tricàlcic a dopat amb silici mitjançant la sinterització d’una hidroxiapatita deficient en calci amb diferents quantitats d’òxid de silici a 1250°C. La presència de silici va estabilitzar el polimorf d’alta temperatura (fosfat tricàlcic a), inhibint-se la reversió de la transformació b-a, mentre que el fosfat tricàlcic a sense silici va revertir completament a polimorf b. La presència de silici no va alterar la temperatura de la transformació b-a. Tant el fosfat tricàlcic a dopat amb silici com el seu homòleg sense silici van ser utilitzats com a reactius en la formulació de ciments de fosfat de calci. Si bé el fosfat tricàlcic a dopat amb silici va mostrar en les fases inicials una hidròlisi més ràpida a hidroxiapatita deficient en calci, un cop completada la reacció, la composició, morfologia i propietats mecàniques d’ambdós ciments van ser similars. L’estudi de bioactivitat mitjançant la immersió de les mostres en fluid corporal simulat va donar com a resultat la formació d’una capa d’apatita a la superfície del ciment dopat amb silici, més ràpida que al seu homòleg sense silici, fet que va suggerir una bioactivitat millorada del ciment dopat. L’estudi in vitro, en el qual cèl·lules osteoblàstiques es van exposar a un medi de cultiu que havia estat prèviament en contacte amb els ciments estudiats, va mostrar un retràs en la proliferació cel·lular i un estímul de la diferenciació cel·lular, aquest últim més marcat pel ciment que contenia silici. Aquests resultats es van atribuir a la reducció de calci en els medis en els quals estaven introduïts els ciments i a l’alliberament continu d’ions silici per part del ciment que en contenia.Postprint (published version

Texture and Colour in Image Analysis

Research in colour and texture has experienced major changes in the last few years. This book presents some recent advances in the field, specifically in the theory and applications of colour texture analysis. This volume also features benchmarks, comparative evaluations and reviews