FMD - Teses de Doutoramento
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- Computational fluid dynamics study on mesial roots of mandibular molarsPublication . Rito Pereira, Mário; Ginjeira, António Manuel Pinto; Faria, Paula Cristina Rodrigues PascoalObjectives: To evaluate the fluid dynamics of syringe irrigation in mesial root canals of mandibular molars. Material and methods: A computational fluid dynamics (CFD) model was experimentally validated using micro-particle image velocimetry (micro-PIV) measurements and subsequently employed to evaluate fluid dynamics in confluent canals acquired by micro-computed tomography (micro-CT) of natural teeth sequentially after mechanical preparation with three different instrument sizes. In addition to root canal enlargement, the influence of the type and depth of needle placement and the presence of anatomical features on the flow pattern, irrigant renewal and penetration, wall shear stress, and apical pressure generated during syringe irrigation were also evaluated. The same methodology and numerical model were applied to independent canals in order to compare the differences in fluid dynamics between the two canal configurations. Results: Root canal configuration and needle type had the greatest effect on the flow pattern, with the other variables having less influence. Irrigation velocity was limited within the isthmuses and accessory canals studied. Apical renewal and penetration of the irrigant were also mainly influenced by root canal configuration. In confluent canals, the depth of confluence relative to the working length (WL) had a direct proportional effect on irrigant penetration and apical renewal. Needle type mostly affected apical penetration in the merged portion of confluent canals, with the open-ended needle always allowing more apical penetration than the side-vented needle, as in independent canals. Although root canal enlargement improved apical renewal and penetration of the irrigant, it had a smaller effect than the previous ones. The depth of needle placement improved apical penetration, except for the side-vented needle in confluent canals, where the results depended on its position relative to the confluence zone. Apical pressure decreased with root canal enlargement, with needle placement further from the WL and with the sidevented needle. Conclusions: The type of root canal configuration affects the irrigant fluid dynamics during syringe irrigation. Confluent canals have a greater influence on irrigant velocity, apical renewal, and penetration compared to independent canals. These factors are mostly improved up to the confluence region. The results imply that when the confluence is closer to the WL, the irrigant's apical renewal and penetration increase during syringe irrigation.
- Development of peri-implant and oral mucosa model for preclinical assessment of new biomaterialsPublication . Fernandes, Beatriz; Marques, Joana Rita Oliveira Faria; Francisco, Helena Cristina de Oliveira; Murdoch, CraigThis doctoral thesis project involves a set of studies aiming to develop and characterise the 3D model of peri-implant mucosa, to compare the biological behaviour of the model in contact with implant surfaces with monolayer cultures, to develop and characterise a model with the presence of a bacterial stimulus, and to evaluate the biological response to surfaces with claimed antibacterial properties with bacterial stimuli. The first phase of this study involved the recruitment of volunteers to collect buccal mucosa and gingiva samples, used for comparison with the models. The peri-implant mucosa models were developed using keratinocytes, fibroblasts and monocytes. To compare the tissue response of the 3D model with the 2D culture, both cultures were placed in contact with Zr and Ti implant surfaces. The models were challenged with P. gingivalis LPS and Pam3CSK4 to evaluate their response and construct a peri-implant mucosa model under inflammation conditions. Finally, implant surfaces of Zirconia and Titanium were coated with MTA and chitosan to contribute to the development of an implant surface with an antibacterial effect and were placed in contact with 2D cultures and 3D models. It was observed that the peri-implant mucosa models developed may be a valid and clinically more relevant alternative to 2D culture. It was also observed that this 3D model responds to the bacterial stimuli used. The results of the study with antibacterial implant surfaces suggest that Chitosan-coated Titanium surfaces appear to be beneficial for peri-implant mucosal cells and MTA/chitosan coating did not show benefits to cellular behaviour in the presence of bacterial stimuli. As a global conclusion, the peri-implant mucosa model can be used for preclinical evaluation of implant surfaces in complement with in vivo analysis. Further in vitro studies with larger sample sizes and complementary study variables should be performed.
- Dental hygienists involvement in public oral health promotion activitiesPublication . Adomaitiene, Rima; Albuquerque, Teresa Maria Beatriz Ramos Esteves Gonçalves dos Santos; Andruskiene, JurgitaThe role of oral hygienists in promoting public oral health in Lithuania is crucial yet underutilized. Despite a high number of oral hygienists, the incidence of oral diseases in the population is increasing, highlighting the need for a comprehensive national prevention program. This study aimed to assess the involvement of oral hygienists in public oral health promotion activities through three research studies: Study I – Contributions of higher education institutions on training of oral hygienists for public oral health promotion activities; Study II – The view of health strategy experts about the profession of oral hygienist and the prospects for promoting public oral health; Study III – The participation of oral hygienists in public oral health educational activities. The findings revealed that while oral hygienists provide individualized oral health promotion, their involvement in broader health promotion activities is limited. However, they acknowledge the importance of public oral health promotion and express willingness to contribute further under certain conditions. These conditions include coordinated activities, provision of resources, and recognition through licensure renewal and remuneration. Health strategy experts recognize the pivotal role of oral hygienists in both personal and public oral care. They advocate for increased involvement of oral hygienists in multidisciplinary teams, integrating them into broader public health initiatives. Furthermore, oral hygienists receive comprehensive training in public health education during their education, engaging with diverse communities in various practice settings. This training equips them with the skills and knowledge necessary to contribute effectively to public oral health promotion. In conclusion, while oral hygienists in Lithuania have the potential to significantly impact public oral health, their involvement in broader health promotion activities requires systematic support and integration into multidisciplinary teams. Establishing a national prevention program and providing necessary resources and recognition can enhance their contribution and mitigate the escalating burden of oral diseases in the population.
- Regeneração periodontal com membrana de colagénio versus membrana de politetrafluoretileno (PTFE) de alta densidade em defeitos intraósseosPublication . Lopes Otão, Pedro; Lopes, Paulo Alexandre Mascarenhas; Almeida, Ricardo Manuel Casaleiro Lobo de Faria eObjetivo: Avaliar o ganho de inserção clínica e o preenchimento ósseo radiográfico em defeitos periodontais intraósseos contidos, recorrendo à abordagem de regeneração tecidular guiada com membranas de politetrafluoretileno de alta densidade (dPTFE) versus membranas de colagénio. Materiais e Métodos: Desde Setembro de 2021 a Outubro de 2023, houve a inclusão de participantes que tivessem indicação para regeneração periodontal e que cumprissem os critérios de inclusão e exclusão selecionados para esta investigação. Os participantes foram distribuídos de forma balanceada e aleatória entre o grupo teste (membranas de dPTFE) e grupo controlo (membranas de colagénio), 15 para o teste e 15 para o controlo. Ambos grupos receberam a mesma técnica cirúrgica, Single Flap Approach (SFA). Todos os participantes receberam o mesmo número de consultas e foram controlados sempre da mesma forma pelo mesmo investigador até ao período de seguimento de 12 meses, onde foram avaliadas as medidas de desfecho principais e secundárias. Resultados: 30 participantes cumpriram o cronograma desta investigação e foram consideradas para análise. O grupo teste e controlo apresentaram ganho de inserção significativo aos 12 meses (4,80±1,2mm vs 4,53±1,6mm, respetivamente), bem como um preenchimento ósseo radiográfico significativo (75,85±13,6% vs 72,04±14,9%, respetivamente), no entanto, sem diferenças estatisticamente significativas entre os grupos. De igual forma nas restantes medidas de desfecho clínicas e radiográficas, também não foram encontradas diferenças estatisticamente significativas entre os grupos de estudo. Conclusões: A regeneração tecidular guiada com membranas de dPTFE apresenta resultados clínicos e radiográficos semelhantes aos conseguidos com as membranas de colagénio para o tratamento de defeitos intraósseos de duas e/ou três paredes para o tempo de seguimento de 12 meses.
- Oral antimicrobial effects of cannabidiolPublication . Torabi, Jila; Luís, Henrique Soares; Hurlbutt, MichelleBackground: Cannabidiol (CBD) is known for its diverse benefits, encompassing analgesic, antioxidant, anti-inflammatory, antimicrobial, anti-pruritic, and anti-cancer properties. This thesis aimed to assess the antimicrobial effects of CBD against oral microorganisms leading to dental caries and periodontal diseases. Methods: Pilot clinical trials were conducted to investigate the effects of CBD on Streptococcus mutans, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans. The first pilot study aimed to compare the anticaries effect of 10mg CBD-infused chewing gum and xylitol gum using the CariScreenTM meter device utilizing adenosine triphosphate bioluminescent technology to measure cariogenic bacterial load in adults at high or extremely high risk for dental caries. In the second pilot clinical trial, the impact of 300 mg Nano CBD-infused lozenges and sugar-free candy on the relative abundance of salivary S. mutans was assessed via quantitative polymerase chain reaction (qPCR). The third clinical trial examined the subgingival antimicrobial effects of 10,000 mg CBD Isolate oil compared to povidone-iodine against Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in adults with periodontal diseases, also utilizing qPCR analysis. Results: Analysis of the clinical trials indicated that CBD-infused gum had no significant effect on salivary cariogenic bacteria. The second trial revealed CBD could potentially reduce the relative abundance of salivary S.mutans (p=0.0299). The results of the third trial revealed the subgingival application of 10,000 mg CBD Isolate oil or PI does not exhibit antimicrobial effects against Aa and Pg in adults with periodontal diseases. Conclusion: CBD has the potential oral antimicrobial properties and may impact the abundance of cariogenic bacteria such as S. mutans in saliva, a primary factor contributing to dental caries disease. These findings highlight the promising role of cannabidiol in dental care and warrant further exploration of its therapeutic potential in oral health. There is a need for further research to investigate the oral health benefits of cannabinoids.
- The role of matrix metalloproteinase (MMP-2 and MMP-9) on the bond strenght of dentine at different levels of the root following different endodontic irrigation protocolsPublication . Baruwa, Abayomi; Ginjeira, António Manuel Pinto; Mazzoni, AnnalisaAim: To identify matrix metalloproteinases (MMP) in root dentine, evaluate the effects of different root canal irrigating solutions on the activity of MMP, push-out bond strength (PBS) and nanoleakage expression (NL) in the root dentin. Methods: Seventy-two teeth were randomly distributed into 4 groups (n=6 for in-situ zymography, n=10 for PBS and n=2 for NL) according to the irrigating solutions used during instrumentation: I) Saline (S); II) 5.25% sodium hypochlorite (NaOCl); III) 5.25% NaOCl + 10% citric acid (CA); IV) 5.25% NaOCl + 10% CA + 0.2% chlorhexidine (CHX). After root canal obturation, post space was prepared with specific drills to receive glass fiber post. Dual-cure resin was used for luting and light-polymerization was performed. The root/fiber post assemblies were sectioned horizontally and subjected to the in-situ zymography, PBS and NL expression analysis tests. The enzymatic activity was quantified and expressed as a percentage of the green fluorescence while fractographic evaluation was performed after PBS with a stereomicroscope and data were statistically analysed at p<0.05. Results and conclusions: The in-situ zymography analysis showed high expression of MMPs in the middle third of the radicular dentine in all groups while the most activity of MMPs following the irrigating solutions was observed in groups I and III. Inversely, group IV recorded the highest PBS, and the statistical analysis of the groups were ranked as follows: IV > II > III > I (p<0.05). The combination of NaOCl, CA and CHX resulted in lower expression of MMP activities and higher push-out bond strength of fiber posts to root dentin, with no difference seen in the nanoleakage expression.
- Hipomineralização Incisivo-molar : estudo laboratorialPublication . Cardoso-Martins, Inês; Marques, Ana Paula Rosa Faria da Conceição; Oliveira, Sofia de Mello Lima Teixeira Santos Arantes eA elevada prevalência mundial da Hipomineralização Incisivo-Molar (HIM), torna-a um potencial problema de saúde pública com grande impacto na sociedade atual. Assim, é de crucial importância estabelecer estratégias terapêuticas preventivas para abordar adequadamente esta patologia. A remineralização do esmalte dentário pode ser conseguida através da aplicação de um complexo de fosfopéptidos de caseína e fosfato de cálcio amorfo (CPP-ACP). No entanto, existe ainda evidência científica limitada que suporte a sua eficácia em dentes afetados por HIM. Neste contexto, esta tese de Doutoramento resulta de um conjunto de estudos que tiveram como objetivo: avaliar a eficácia da ação remineralizante do CPP-ACP em diferentes tipos de opacidades - brancas e amarelas de primeiros molares permanentes com HIM, observar as diferentes características estruturais e mecânicas do esmalte de dentes afetados por esta patologia, e associar a presença de células inflamatórias pulpares ao grau de envolvimento coronário da lesão em dentes com HIM. A eficácia da acção remineralizante de um protocolo de 28 dias de aplicação de CPP-ACP em dentes com HIM in vitro foi avaliada recorrendo à análise da microdureza de Vickers, à espectroscopia Raman e à microscopia eletrónica de varrimento (SEM). Foi ainda realizado um estudo com recurso à microscopia ótica (MO) para observar a existência de células inflamatórias pulpares em dentes com HIM e estabelecer uma associação com a severidade da lesão. No estudo de microdureza foram realizadas comparações intra-grupo e entre grupos de dentes hipomineralizados com opacidades brancas e amarelas utilizando testes paramétricos (t de student emparelhado e t para amostras independentes) e não paramétricos (Wilcoxon Sign Rank e Mann-Whitney U). No estudo de Raman os resultados pré/pós tratamento com CPP-ACP dos três grupos (com opacidades brancas, amarelas e dentes hígidos) foram analisados recorrendo ao teste estatístico one-way ANOVA (LSD-Post-hoc). Em todos os estudos foi considerado um nível de significância (p) de 0.05. Procedeu-se também à análise dos resultados das características estruturais do esmalte observadas em SEM. Foi realizada ainda a análise observacional dos resultados do estudo das polpas dentárias em MO. Os resultados destes estudos revelam ter havido um aumento significativo da resistência mecânica e melhorias acentuadas na morfologia superficial e na xiv organização dos cristais de hidroxiapatite do esmalte hipomineralizado após a aplicação tópica de CPP-ACP. Assim sendo, estes resultados sugerem ter havido uma remineralização significativa do esmalte após uma aplicação diária consecutiva de uma pasta contendo CPP-ACP durante 28 dias. A análise das polpas revelou a presença de inflamação pulpar subclínica em dentes hipomineralizados, sugerindo que possa ocorrer penetração bacteriana através das porosidades do esmalte em dentes com HIM, que poderá contribuir para a eventual hipersensibilidade associada a esta patologia. Desta forma, o uso de estratégias terapêuticas preventivas com este nanoagregado, poderá por um lado, minimizar o risco de fratura de esmalte pós-eruptiva e de falha dos materiais restauradores, e por outro limitar a infiltração bacteriana e melhorar a hipersensibilidade em dentes hipomineralizados. As melhorias observadas nas características estruturais e mecânicas do esmalte hipomineralizado sustentam a realização de mais estudos in vitro e in vivo, de forma a desenvolver uma recomendação para o uso do CPP-ACP em dentes com HIM.
- Impacto do HIV-1/HIV-2 e terapia antirretroviral altamente ativa na qualidade de vida e saúde oral do doente portador de HIV/SIDAPublication . Rocha Trindade, Ruben; Mata, António Duarte Solo Pereira da; Marques, Duarte Nuno da SilvaCom a introdução da terapia antirretroviral, a taxa de mortalidade dos indivíduos com HIV/SIDA tem vindo a diminuir e a respetiva esperança média de vida a aproximar-se da população seronegativa. Atualmente, esta mudança de paradigma direcionou o foco de atuação dos serviços de saúde, nestes pacientes, para uma melhoria da qualidade de vida. Esta tese reúne três estudos cujos objetivos principais englobam a caracterização socioeconómica e do estado de saúde oral, a avaliação do impacto da infeção por HIV e da reabilitação oral (RO) na qualidade de vida relacionada com a saúde oral (OHRQoL), numa amostra da população portuguesa infetada/afetada pelo HIV. Inicialmente, foram realizados dois estudos seccionais cruzados, o primeiro, referente à caracterização, demonstrou que o estado de saúde oral das pessoas infetadas/afetadas pelo HIV no nosso estudo é bastante deficitário com evidentes carências e elevadas necessidades de RO. No segundo, referente ao impacto do HIV na OHRQoL, obteve-se um modelo preditivo da OHRQoL, com as pontuações totais ajustadas do OHIP-49 a apresentarem valores significativamente mais elevados (p<0,001) no grupo HIV1 (119,8 ± 3,31) que no HIV- (61,6 ± 6,26), com um tamanho de efeito grande (0,94). Por último, foi realizado um estudo prospetivo, para avaliar o impacto da RO na OHRQoL, onde foram detetadas melhorias significativas (p<0,001) em todas as perguntas do OHIP-49 em ambos os grupos e após RO, porém, com o grupo HIV1 a continuar a apresentar pior OHRQoL que o HIV- (p<0,001). Estes estudos constituem a primeira demonstração do impacto diferencial dos tratamentos dentários na melhoria da OHRQoL em pacientes com HIV. Os resultados também sugerem que, independentemente do estabelecimento de um plano de reabilitação oral, a infeção pelo HIV representa, per se, uma variável com um efeito negativo independente e significativo na OHRQoL.
- Effects of different clinical protocols in tooth bleaching efficacy, tooth colour assessment and oral health-related quality of lifePublication . Pereira, Ruben Miguel; Marques, Duarte Nuno da Silva; Silveira, João Miguel LourençoObjectives: To compare efficacy, long-term stability, and impact on oral health related quality of life of different tooth bleaching techniques and clinical protocols while evaluating different tooth colour assessment methods and their colour perception. Materials and methods: Three clinical studies were individually designed. The first evaluated the effect of dental prophylaxis on tooth colour perception and the visual assessment’s reliability when compared to spectrophotometry. In the second the application of an in-office paint-on varnish with different soft-tissues protecting materials and its bleaching efficacy was evaluated. The last study evaluated tooth colour/whiteness and OHIP-14-PT scores at different stages with three different bleaching systems. CIELAB formulas were used to quantify colour space differences (ΔE00/ΔWID) and were applied in all studies while considering its respective perceptibility/acceptability thresholds. For statistical analyses was set a 5% significance level. Results: Tooth colour differences higher than the perceptibility threshold were systematically detected post-prophylaxis by both visual and spectrophotometric methods. An in-office paint-on varnish presented significantly higher (P0.05). Conclusions: The influence of dental prophylaxis in tooth colour perception and of different soft-tissues protecting materials in in-office bleaching efficacy were determined for the first time. The proposed modification for an in-office paint-on varnish technique attained both bleaching efficacy and oral health-related quality of life improvement while presenting a lesser application time when compared with equal concentration systems.
- Digital Technology for the Production of Removable Partial Denture Metal FrameworksPublication . Conceição, Pedro Rodrigues; Neves, Maria Cristina Bettencourt; Portugal, Jaime Pereira Fontes de AlmeidaObjectives: To review the fit accuracy results of removable partial dentures (RPDs) metal frameworks produced by different digital protocols. To evaluate methods for the fit accuracy assessment of RPD metal frameworks to the supporting structures. To clinically evaluate RPD metal frameworks produced by digital technology. Materials and methods: A systematic review was elaborated to identify the digital protocols of framework production and the corresponding fit accuracy assessment previously described. In vitro study of direct (digital superimposition and inspection) and indirect (mold thickness measure by micro-computed tomography) assessment of the gap between the occlusal rests (n= 34) and their respective rest seats. For twenty-six dental arches (n= 26) two RPD Co-Cr frameworks production protocol (experimental digital vs conventional lost-wax) were compared for production repetition, components adjusted until correct insertion, clinical acceptability, components maladjustment and thickness and volume of occlusal rest silicone molds determined by micro-computed tomography. Data were analyzed using adequate parametric or non-parametric tests (α= 0.05). Results: The most described protocol was the direct additive manufacturing using conventional impression, which showed better outcomes. A strong positive correlation (ρ= 0.612) between quantitative methods was verified and no difference (p = 0.595) was found between the qualitative data. Digital production protocol presented similar results than control, with the exception of lower production repetitions (p= 0.046), higher components adjusted (p= 0.011) and lower reciprocal arms maladjustment (p= 0.044). Conclusions: The results of this thesis suggest that the direct additive manufacturing using conventional impression is a feasible method to produce RPD metal frameworks, considering the applyed assessment methods.