Evaluation of Candida species biofilm formation on acrylic resin and denture liners used in prosthodontics

Orientador: Altair Antoninha Del Bel CuryTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A candidose é a infecção oral fúngica mais comum diagnosticada em humanos, com prevalência de até 77,5% em usuários de próteses removíveis. Embora tenha sido inicialmente associada apenas à Candida albicans, outras espécies de Candida podem ser responsáveis por mais de 50% dos casos de infecção. Ainda, fatores como presença de saliva, bactérias e características de materiais utilizados para confecção de próteses removíveis parecem desempenhar importante papel na adesão, colonização e formação de biofilme por Candida. Assim, este trabalho objetivou (i) discutir os fatores que controlam a adesão inicial, colonização e formação de biofilme de Candida em um artigo de revisão, no intuito de apontar diretrizes para estudos futuros e ainda, mostrar de que forma estes fatores podem ser controlados, ajudando na prevenção da doença; (ii) verificar a influência in vitro de alguns dos fatores supracitados na formação de biofilme de C. albicans sobre a superfície de hidroxiapatita, resina acrílica e reembasador temporário e; (iii) avaliar in situ a formação de biofilme sobre espécimes de resina acrílica e reembasadores de próteses inseridos nas próteses totais de 21 voluntários. Para avaliação da formação de biofilme de C. OBS.: O resumo na integra poderá ser visualizado no link ou texto completo da tese digital.Abstract: Candida-associated stomatitis is the most common fungal oral infection in humans, with a prevalence reported in up to 77.5% of a population wearing dentures. Disease-associated Candida species have shifted from C. albicans to non-albicans species, these latter being responsible for more than 50% of the infections. Additionally, several factors as the presence of saliva, bacteria and dental prostheses materials¿ characteristics seem to be related to the adhesion, colonization and biofilm formation of Candida. This study aimed (i) to discuss the factors that govern initial adherence, colonization and biofilm formation of Candida by means of a review article, in order to suggest future research and show how these factors may be controlled, therefore helping to prevent the disease; (ii) to verify the influence of several of these factors in the biofilm formation of C. albicans in vitro, on hydroxyapatite, acrylic resin and soft denture liner; (iii) to evaluate in situ biofilm formed on acrylic resin and denture liner specimens inserted in the lower dentures of 21 volunteers. For C. Note: the complete abstract is avaiable with the link or full eletronic digital theses or dissertations.DoutoradoProtese DentalDoutor em Clínica Odontológic

Influence of thermal stress on marginal integrity of restorative materials

The aim of this study was to evaluate the influence of thermal stress on the marginal integrity of restorative materials with different adhesive and thermal properties. Three hundred and sixty Class V cavities were prepared in buccal and lingual surfaces of 180 bovine incisors. Cervical and incisal walls were located in dentin and enamel, respectively. Specimens were restored with resin composite (RC); glass ionomer (GI) or amalgam (AM), and randomly assigned to 18 groups (n=20) according to the material, number of cycles (500 or 1,000 cycles) and dwell time (30 s or 60 s). Dry and wet specimens served as controls Specimens were immersed in 1% basic fuchsine solution (24 h), sectioned, and microleakage was evaluated under x40 magnification. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests: Thermal cycling regimens increased leakage in all AM restorations (

Fracture resistance of premolars restored with inlay and onlay ceramic restorations and luted with two different agents

AbstractPurposeThe purpose of this study was to evaluate the fracture resistance of human maxillary premolars restored with 2 ceramic systems (Vitadur Alpha and In Ceram) comparing 3 preparation designs and 2 luting agents.MethodsSeventy sound teeth were prepared to receive ceramic restorations (Vitadur Alpha; n=14) as follows: (1) control, sound premolars, with no preparation, (2) inlays, (3) partial onlays (palatal cuspid coverage), (4) total onlays (both cuspids coverage), and (5) total onlays with an In Ceram core. The ceramic restorations were cemented using Enforce or RelyX ARC (half restorations with each cement), placed into the cavity and held under pressure, except for the control group. The teeth were subjected to compressive axial loading at 0.5mmmin−1 using a 9mm steel ball until fracture. Data were analyzed by 3-way ANOVA and post hoc Tukey's test (α=.05).ResultsThere was a significant difference between cements and among preparation designs (P<.05). All restorations cemented with Enforce exhibited significantly higher fracture resistance (P<.05). Inlay restorations showed similar fracture resistance when compared to control group (P>.05). Partial and total onlays did not statistically differ and showed the weakest performance. The use of an In Ceram core did not produce higher fracture resistance.ConclusionsWithin the limitations of this study, the cements tested had different mechanical properties, while cuspid coverage did not result in improved fracture resistance of the restored teeth

The Effect of Luting Agents and Ceramic Thickness on the Color Variation of Different Ceramics against a Chromatic Background

Objectives: The aim of this study was to assess the influence of various ceramic thicknesses and luting agents on color variation in five ceramic systems. Methods: Fifteen disc-shaped ceramic specimens (11 mm diameter; shade A3) were fabricated with each of the six veneering ceramics tested, with 1, 1.5, or 2 mm thickness (n=5). Resin composite discs (Z-250, shade C4) were used as bases to simulate a chromatic background. The cementation of the veneers was carried out with an opaque resin-based cement (Enforce, shade C4), a resin-based cement (Enforce, shade A3), or without cement (C4, control group). Color differences (??E*) were determined using a colorimeter. Three-way ANOVA was used to analyze the data, followed by a Tukey post-hoc test (??=.05). Results: The L*a*b* values of the ceramic systems were affected by both the luting agent and the ceramic thickness (P<.05). In general, there was no difference between the control group and the group using the resin-based cement. The use of an opaque luting agent resulted in an increase of the color coordinates a*, b*, L*, producing differences in ??E* values for all ceramics tested, regardless of the thickness (P<.05). For the 2-mm thick veneers, higher values in the color parameters were obtained for all ceramics and were independent of the luting agent used. Conclusions: The association of 2-mm thickness with opaque cement presented the strongest masking ability of a dark colored background when compared to a non- opaque luting agent and the other thicknesses tested. (Eur J Dent 2011;5:245-252

Characteristics of systematic reviews published in dentistry by Brazilian corresponding authors

OBJECTIVE: This study aimed to analyze the reporting and conduct characteristics of systematic reviews (SRs) published in dentistry by Brazilian corresponding authors and compare reporting characteristics of Brazilian SRs with the rest of the world. METHODS: A search in PubMed was performed to identify SRs published in dentistry in 2017 assessing different aspects of oral heath irrespective of the design of included studies. From this dataset, a subgroup analysis was performed considering only SRs published by Brazilian corresponding authors. Study screening was performed by two researchers independently, while for data extraction, one of three reviewers extracted details related to reporting and conduct of SRs. The completeness of reporting of 24 characteristics, included in the PRISMA Statement of the SRs classified as treatment/therapeutic, was evaluated comparing Brazilian SR to SRs from all other countries. RESULTS: We included 117 SRs with Brazilian corresponding authors. The majority focused on dental treatments (39.3%), with oral surgery (n=19, 16.2%) as the most commonly published. Included SRs presented varying reporting/conduct characteristics. Items such as use of reporting guidelines and screening method used were well reported. However, most SRs did not assess the risk of publication bias and did not use the GRADE assessment. Four (of 24) reporting characteristics of Brazilian SRs compared to SRs from the rest of world were reported statistically significantly more frequently: mention of a SR protocol, trial registry searched, screening method reported, and assessment of risk of bias/quality of studies. CONCLUSION: Reporting and conduct characteristics of Brazilian SRs are highly variable.

Padrões estéticos dentais em pessoas com e sem sorriso gengival Dental aesthetic patterns in persons with and without gingival smile

Introdução e Objetivo: O presente estudo avaliou o comprimento e a proporção dentária em dentes anterossuperiores de pacientes com e sem sorriso gengival. Material e métodos: Selecionaram-se 38 indivíduos para cada um dos grupos: caso (sorriso gengival) e controle. Modelos de gesso foram obtidos mediante moldagem das arcadas, para então serem realizadas as mensurações. Também se submeteram os pacientes a um breve questionário. Resultados: Os dados foram tabulados e analisados por meio de análise de variância sob um nível de significância de 5%. Em ambos os grupos, a maioria foram mulheres (68,4%), brancos (98,7%), com idade variando de 18 a 28 anos. A maior altura encontrada foi para o dente 21 do grupo controle (9,88 mm), e a maior proporção para o dente 11 do grupo caso (87,43%). Analisando a classe dentária, somente a proporção dos incisivos centrais dos casos foram estatisticamente diferentes (p = 0,041), com uma proporção maior. Conclusão: Indivíduos com sorriso gengival possuem proporção dentária maior do que aqueles que não apresentam, entretanto nem todos os dentes podem ter tal diferença.Introdução e Objetivo: O presente estudo avaliou o comprimento e a proporção dentária em dentes anterossuperiores de pacientes com e sem sorriso gengival. Material e métodos: Selecionaram-se 38 indivíduos para cada um dos grupos: caso (sorriso gengival) e controle. Modelos de gesso foram obtidos mediante moldagem das arcadas, para então serem realizadas as mensurações. Também se submeteram os pacientes a um breve questionário. Resultados: Os dados foram tabulados e analisados por meio de análise de variância sob um nível de significância de 5%. Em ambos os grupos, a maioria foram mulheres (68,4%), brancos (98,7%), com idade variando de 18 a 28 anos. A maior altura encontrada foi para o dente 21 do grupo controle (9,88 mm), e a maior proporção para o dente 11 do grupo caso (87,43%). Analisando a classe dentária, somente a proporção dos incisivos centrais dos casos foram estatisticamente diferentes (p = 0,041), com uma proporção maior. Conclusão: Indivíduos com sorriso gengival possuem proporção dentária maior do que aqueles que não apresentam, entretanto nem todos os dentes podem ter tal diferença

In vitro Candida spp adhesion on acrylic resins and denture liners

Orientadores: Altair Antoninha Del Bel Cury, Renata Cunha Matheus Rodrigues-GarciaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A candidose é a infecção oral fúngica mais comum diagnosticada em humanos, com prevalência de até 67% em usuários de prótese. Embora tenha sido inicialmente associada apenas a Candida albicans, outras espécies podem ser responsáveis por mais de 50% dos casos de infecção. Ainda, fatores como presença de saliva e bactérias parecem desempenhar importante papel na colonização por Candida. Assim, este estudo objetivou verificar a influência destes fatores na a:fesão de duas espécies de Candida (Candida albicans e Candida glabrata) sobre a superfície de resinas acrílicas e reembasadores. Corpos de prova (2,5x1 ,2xO,2 cm) confeccionados com duas resinas acrílicas (convencional e de microondas) e dois reembasadores (temporário e permanente) tiveram sua rugosidade (Ra) e energia livre de superfície (ELS) mensuradas, sendo aleatoriamente divididos de acordo com a exposição aos fatores: presença ou ausência de saliva, presença ou ausência de bactérias e espécie de Candida. Os espécimes foram levados a uma câmara de fluxo utilizando-se uma bomba peristáltica para perfusão de cultura de bactérias seguida por uma das espécies de Candida, ou apenas a cultura de uma das espécies de Candida. A contagem das células de Candida aderidas foi realizada em microscópio óptico (400x). Os dados foram submetidos à análise de variância para Ra e adesão, e ao teste de Kruskal-Wallis para ELS (a=0,05). O reembasador temporário apresentou a maior Ra, seguido do permanente, enquanto as resinas acrílicas exibiram as menores rugosidades (p<0,0001). Os valores de ELS foram similares para os materiais, mas diferentes do reembasador temporário (p<0,0001). A adesão de C. albicans e C. glabrata variou de 3,2 a 564,4 e 3,2 a 1400,4 cel/mm2 respectivamente, com diferenças estatísticas (p<0,05) em alguns grupos. O reembasador temporário mostrou maiores níveis de adesão. A colonização foi diminuída pela saliva, enquanto na presença de bactérias e saliva houve aumento da adesão (p<0,05). Estes resultados sugerem que a adesão inicial das duas espécies de Candida foi fortemente afetada pela rugosidade, presença de saliva e bactérias, mas não pela energia livre de superfícieAbstract: Candida-associated stomatitis is reported in up to 67% of a population wearing dentures. Recently, disease-associated Candida species have shifted from C. albicans to norralbicans species. Since factors such as presence of saliva and oral bacteria appear to play a major role in the initial phases of yeasts adhesion, this study aimed to determine whether these factors produced differences in acrylic resins and denture liners C. albicans and C. glabrata adherence. Samples (2.5x1.2xO.2 em) of two acrylic resins (heat and microwavecured) and two denture liners (soft and hard) were prepared and had their surface free energy (SFE) and surface roughness (Ra) measured and were randomly divided according to their exposure to the following factors: saliva coating or uncoating, presence or absence of bacteria and Candida species. Specimens were assayed in a flow chamber connected to a peristaltic pump for perfusion of bacteria culture plus one of the Candida species culture or only the Candida culture (control). Adhesion was determined by count on a light microscope (400 x). Statistical analyses was performed by ANOVA (Ra and Candida species adhesion) and Kruskal-Wallis (SFE) (a=.05). Soft liner presented the roughest surface, followed by the hard liner, whereas acrylic resins exhibited the smoothest surfaces (p<.0001). The SFE values of ali materiais were similar but different from the soft liner (p<.0001). C. albicans and C. glabrata adhesion on the materiais ranged fr0m 3.2 to 564.4, and 3.2 to 1400.4 cells mm-2 respectively, with statistically signific,ant differences (p<.05) in some cases. The soft liner exhibited the highest levels of adhesion. The overall colonization was significantly decreased by saliva (p<.Oq), while bacteria increased the adhesion in the presence of saliva. These results taken together suggest that initial adhesion of Candida species was strongly affected by the surface roughness, presence of saliva and bacteria, but not by surface free energyMestradoProtese DentalMestre em Clínica Odontológic