Introduction: Tooth bleaching has been an increasing demand [1] since tooth discolorations can ha... more Introduction: Tooth bleaching has been an increasing demand [1] since tooth discolorations can have a negative impact on the social and psychological behaviour of patients. Internal bleaching (IB) can be used to treat teeth with endodontic treatment that are quite susceptible to pigmentation. The success of this technique depends on the ability to diffuse the active bleaching agent through pigments [2]. Thus, prior acid etching (PAE) of the pulp chamber has been proposed in order to remove the smear layer and to open the dentinal tubules, allowing a greater penetration of the bleaching agent S48 ABSTRACTS
Introduction: Dental bleaching is regarded as a safe medical treatment for those who want to achi... more Introduction: Dental bleaching is regarded as a safe medical treatment for those who want to achieve a brighter smile. Bleaching is a chemical process in which oxidation occurs, affecting the way teeth absorb or reflect light [1]. Oxidative ability of bleaching agents and the presence of free hydroxyl radicals in the apatite modifies the mineral and protein composition of the enamel increasing its solubility. This renders the enamel surface adverse to the best bonding conditions [2,3]. Some strategies, including antioxidants such as sodium ascorbate, are capable of re-establishing the bond strength to nearest normal values, showing to be an effective method when used immediately after dental bleaching treatment [4,5]. The purpose of this study is to evaluate the effect of an antioxidant on the microtensile bond strength of bleached teeth that were subsequently restored, comparing different waiting times for the procedure. Materials and methods: Thirty human permanent molars were sectioned into halves (n ¼ 60), and randomly distributed between three groups: control (CG), bleaching (G1) and bleaching þ sodium ascorbate (G2). Groups G1 and G2 were bleached 2 h/day for a 7-day period. After bleaching, G2 received a 10% sodium ascorbate gel for 50 min. In each group, samples were divided in equal parts where one part (n ¼ 5) was immediately restored with an adhesive system and a resin composite (T0) and the other half (n ¼ 5) was stored, in artificial saliva at 37 C, and restored after 7 days (T1). After 24 h, samples were sectioned into microspecimens ($1mm 2) and tested at a crosshead head-speed of 0.5 mm/min. Data analysis was performed using a factorial ANOVA, at a significance level of 5%. Results: Groups in which sodium ascorbate was applied presented mean mTBS values (G2T0: 22.1 ± 3.3 MPa; G2T1: 24.5 ± 2.9 MPa) significantly higher than the bleaching only and immediately restored group (G1T0, 10.9 ± 3.3 MPa) (p < .001). The group in which teeth were beached and restored after 7 days (G1T1, 19.4 ± 2.6 MPa) showed significantly higher values than the group immediately restored after bleaching (G1T0) (p ¼ .006). No significant differences were found between the groups in which sodium ascorbate was applied (G2) and the group in which teeth were bleached and restored after 7 days (G1T1) (p > .05). Discussion and conclusions: Sodium ascorbate is capable of capturing free oxygen radicals retained on the enamel. These promote decomposition of hydrogen peroxide, which in turn prevents the complete polymerisation of the adhesive system thus affecting bond strength [2,5]. The application of sodium ascorbate is an effective alternative to improve bond strength when compared to a waiting period before the restorative procedure.
Collagen cleavage by matrix metalloproteinase (MMP) is considered a major cause of dental resins ... more Collagen cleavage by matrix metalloproteinase (MMP) is considered a major cause of dental resins long term failure. Most MMP inhibitors display significant toxicity and are unsuitable for dental resins’ applications. Here we report a study of a new class of inhibitors that display the unique property of being co-polymerizable with other vinyl compounds present in commercial dental resins, limiting their release and potential toxicity. Computational affinity towards the active site of different MMP-1; -2; -8; -9 and -13 of several compounds showed interesting properties and were synthesized. These free compounds were tested concerning their toxicity upon contact with two different cell types, with no substantial decrease in cell viability at high concentrations. Even so, compound’s safety can be further improved upon copolymerization with commercial dental resins, limiting their release.
Xerostomia (dry mouth perception) is a condition that affects mastication, swallowing and speech ... more Xerostomia (dry mouth perception) is a condition that affects mastication, swallowing and speech and increases with age or can be the result of medication or some systemic diseases. The purpose of this exploratory study was to evaluate the prevalence of xerostomia in a local elderly population and its relationship with medication. It was verified that most of the participants have xerostomia, and from these, the majority take medication. Additionally, the prevalence of xerostomia varies with the type of medication taken. The presence of xerostomia was found to be significantly related to the number of medications taken.
Matrix metalloproteinases are enzymes that degrade the extracellular matrix. They have different ... more Matrix metalloproteinases are enzymes that degrade the extracellular matrix. They have different substrates but similar structural organization. Matrix metalloproteinases are involved in many physiological and pathological processes and there is a need to develop inhibitors for these enzymes in order to modulate the degradation of the extracellular matrix (ECM). There exist two classes of inhibitors: endogenous and synthetics. The development of synthetic inhibitors remains a great challenge due to the low selectivity and specificity, side effects in clinical trials, and instability. An extensive review of currently reported synthetic inhibitors and description of their properties is presented.
Due to their polymerization characteristics, hyper-branched dendrimers have lately shown to be pr... more Due to their polymerization characteristics, hyper-branched dendrimers have lately shown to be promising candidates for use in dental materials. In this study, a new dental adhesive system was prepared, using a dendrimer derived from 2-isocyanatoethyl methacrylate (G-IEMA), and its adhesive properties were investigated. The exposed dentin was treated with four universal adhesives (UAs): SBU (Scotchbond Universal™), FUT (Futurabond M+™), AE1 (experimental adhesive with Bis-GMA) and AE2 (experimental adhesive with G-IEMA), using Etch & Rinse (ER) or Self Etch (SE) protocols. Composite build-ups were prepared and stored for 24 h at 37 °C in distilled water. Composite/dentin beams were prepared with cross-sectional areas of 1 ± 0.3 mm2 and µTBS (Micro-tensile bond strength) test was performed at 0.5 mm/min. Failures modes were evaluated by stereomicroscopy, and bonding interfaces were observed by scanning electron microscopy (SEM). Statistical analysis of µTBS data was performed using G...
Introduction: A removable intraoral device is often manufactured in hard acrylic that is placed o... more Introduction: A removable intraoral device is often manufactured in hard acrylic that is placed over the incisal and occlusal surfaces of the teeth [1]. Currently the state of competitive anxiety is mostly observed as a specific situation constructed multidimensionally with a component both somatic and cognitive being that this situation affects the motor and cognitive performance of the athletes during the competition [2]. This study aimed to analyze the changes in the state of anxiety with the use of intraoral devices in Golf athletes. Materials and methods: After study approval by the Ethic Commission of the Cooperativa de ensino Egas Moniz, athletes from the Centro Nacional de Formac¸ão de Golfe do Jamor (CNFGJ) were invited to participate in this study. Following the informed consent a Diagnostic Criteria for Temporomandibular Disorder was applied. Inclusion criteria: Athletes of both genders who have signed informed consent with handicap <20 or professional. Exclusion criteria: Patients With TMD; Kennedy-Applegate Class I or II. In order to ensure anonymization all data were coded. Individualized intraoral devices (IOD) were developed for each athlete. Athletes held a 9-hole tournament with two phases: one phase without and another with the use of the IOD. To analyze the stress levels, it was requested the completion of the Competitive State Anxiety Inventory-II. Linear mixed effect models were used to evaluate the effect of the use the intraoral device, evaluation moment and interaction between them and the anxiety levels. Significance of these effects was assessed through the analysis of variance of type III with Kenward-Roger approximation for degrees of freedom. Results: The sample was composed of 8 athletes, with an average age of 27.3 (±7,32) years. The model developed to evaluate the effect of the IOD, evaluation season and their interaction on the anxiety state showed not to be significantly different from the null model (v 2 (3) ¼ 7.5918, p < 0.055). Discussion and conclusion: Statistically the use of IOD did not change in the subjective levels of anxiety, however the results need to be supported by larger and more significant samples CONTACT Pedro Cebola
Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia Maxilofacial
as resinas compostas. Existiram diferenç as estatisticamente significativas entre os valores inic... more as resinas compostas. Existiram diferenç as estatisticamente significativas entre os valores iniciais de rugosidade após polimento entre resinas compostas. Existiram, igualmente, diferenç as estatisticamente significativas entre os valores de rugosidade pós-escovagem entre as resinas compostas.
Currently, there is lack of human in vitro full tooth models that hold the odontoblast layer with... more Currently, there is lack of human in vitro full tooth models that hold the odontoblast layer with pulp tissue in their native environment. The appearance of new in vitro and in vivo models has provided new understanding of the potential of tissue engineering in dental pulp regeneration. However, the development of new in vitro full tooth models will allow us to get closer to in vivo conditions. Thus, the aim of this study is to preserve a living dentin-pulp complex, in a novel in vitro full crown model, after tooth extraction. Twenty intact third molars, after preparation, were divided into four groups, with five samples each. We placed the negative control samples (C) in saline, and the tested groups were placed (T) in supplemented DMEM, at two different times: 1 and 7 days. The specimens were processed for light microscopy observation. Contrary to C-groups, T-groups showed a functional dentin-pulp complex. The treated dentin-pulp complex presents normal histological appearance. Th...
Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia Maxilofacial, 2015
Introdução Ao longo dos anos, um dos principais objectivos tem sido o fabrico de resinas composta... more Introdução Ao longo dos anos, um dos principais objectivos tem sido o fabrico de resinas compostas com baixa contracção de polimerização e consequentemente menor stress de polimerização. 1,2,3,4 Neste sentido, vários fabricantes desenvolveram as resinas compostas bulk fill, que podem ser aplicadas em camadas de 4 mm, com polimerização aumentada e contracção controlada. 5 Objectivo Avaliar in-vitro a microinfiltração marginal, em restaurações de Classe II, efectuadas pela técnica directa, com resinas compostas de profundidade de polimerização aumentada. Resultados Após a observação e medição com a lupa estereoscópica, da penetração do corante, associada a cada grupo, os valores foram registados como demonstra a Tabela 1 Conclusão Este estudo demonstrou que nenhuma das resinas compostas de polimerização aumentada foi capaz de promover um selamento eficaz.
Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia Maxilofacial, 2015
Vários são os estudos sobre materiais dentários que usam dentes humanos previamente extraídos, os... more Vários são os estudos sobre materiais dentários que usam dentes humanos previamente extraídos, os quais são colocados em soluções de armazenamento de forma a prevenir a sua desidratação 1,2,3. No entanto, os meios em que os dentes são armazenados podem interferir nas propriedades físicas e ópticas dos mesmos, levando a alterações nos resultados dos estudos experimentais 4,5,6,7 .
Introduction: Tooth bleaching has been an increasing demand [1] since tooth discolorations can ha... more Introduction: Tooth bleaching has been an increasing demand [1] since tooth discolorations can have a negative impact on the social and psychological behaviour of patients. Internal bleaching (IB) can be used to treat teeth with endodontic treatment that are quite susceptible to pigmentation. The success of this technique depends on the ability to diffuse the active bleaching agent through pigments [2]. Thus, prior acid etching (PAE) of the pulp chamber has been proposed in order to remove the smear layer and to open the dentinal tubules, allowing a greater penetration of the bleaching agent S48 ABSTRACTS
Introduction: Dental bleaching is regarded as a safe medical treatment for those who want to achi... more Introduction: Dental bleaching is regarded as a safe medical treatment for those who want to achieve a brighter smile. Bleaching is a chemical process in which oxidation occurs, affecting the way teeth absorb or reflect light [1]. Oxidative ability of bleaching agents and the presence of free hydroxyl radicals in the apatite modifies the mineral and protein composition of the enamel increasing its solubility. This renders the enamel surface adverse to the best bonding conditions [2,3]. Some strategies, including antioxidants such as sodium ascorbate, are capable of re-establishing the bond strength to nearest normal values, showing to be an effective method when used immediately after dental bleaching treatment [4,5]. The purpose of this study is to evaluate the effect of an antioxidant on the microtensile bond strength of bleached teeth that were subsequently restored, comparing different waiting times for the procedure. Materials and methods: Thirty human permanent molars were sectioned into halves (n ¼ 60), and randomly distributed between three groups: control (CG), bleaching (G1) and bleaching þ sodium ascorbate (G2). Groups G1 and G2 were bleached 2 h/day for a 7-day period. After bleaching, G2 received a 10% sodium ascorbate gel for 50 min. In each group, samples were divided in equal parts where one part (n ¼ 5) was immediately restored with an adhesive system and a resin composite (T0) and the other half (n ¼ 5) was stored, in artificial saliva at 37 C, and restored after 7 days (T1). After 24 h, samples were sectioned into microspecimens ($1mm 2) and tested at a crosshead head-speed of 0.5 mm/min. Data analysis was performed using a factorial ANOVA, at a significance level of 5%. Results: Groups in which sodium ascorbate was applied presented mean mTBS values (G2T0: 22.1 ± 3.3 MPa; G2T1: 24.5 ± 2.9 MPa) significantly higher than the bleaching only and immediately restored group (G1T0, 10.9 ± 3.3 MPa) (p < .001). The group in which teeth were beached and restored after 7 days (G1T1, 19.4 ± 2.6 MPa) showed significantly higher values than the group immediately restored after bleaching (G1T0) (p ¼ .006). No significant differences were found between the groups in which sodium ascorbate was applied (G2) and the group in which teeth were bleached and restored after 7 days (G1T1) (p > .05). Discussion and conclusions: Sodium ascorbate is capable of capturing free oxygen radicals retained on the enamel. These promote decomposition of hydrogen peroxide, which in turn prevents the complete polymerisation of the adhesive system thus affecting bond strength [2,5]. The application of sodium ascorbate is an effective alternative to improve bond strength when compared to a waiting period before the restorative procedure.
Collagen cleavage by matrix metalloproteinase (MMP) is considered a major cause of dental resins ... more Collagen cleavage by matrix metalloproteinase (MMP) is considered a major cause of dental resins long term failure. Most MMP inhibitors display significant toxicity and are unsuitable for dental resins’ applications. Here we report a study of a new class of inhibitors that display the unique property of being co-polymerizable with other vinyl compounds present in commercial dental resins, limiting their release and potential toxicity. Computational affinity towards the active site of different MMP-1; -2; -8; -9 and -13 of several compounds showed interesting properties and were synthesized. These free compounds were tested concerning their toxicity upon contact with two different cell types, with no substantial decrease in cell viability at high concentrations. Even so, compound’s safety can be further improved upon copolymerization with commercial dental resins, limiting their release.
Xerostomia (dry mouth perception) is a condition that affects mastication, swallowing and speech ... more Xerostomia (dry mouth perception) is a condition that affects mastication, swallowing and speech and increases with age or can be the result of medication or some systemic diseases. The purpose of this exploratory study was to evaluate the prevalence of xerostomia in a local elderly population and its relationship with medication. It was verified that most of the participants have xerostomia, and from these, the majority take medication. Additionally, the prevalence of xerostomia varies with the type of medication taken. The presence of xerostomia was found to be significantly related to the number of medications taken.
Matrix metalloproteinases are enzymes that degrade the extracellular matrix. They have different ... more Matrix metalloproteinases are enzymes that degrade the extracellular matrix. They have different substrates but similar structural organization. Matrix metalloproteinases are involved in many physiological and pathological processes and there is a need to develop inhibitors for these enzymes in order to modulate the degradation of the extracellular matrix (ECM). There exist two classes of inhibitors: endogenous and synthetics. The development of synthetic inhibitors remains a great challenge due to the low selectivity and specificity, side effects in clinical trials, and instability. An extensive review of currently reported synthetic inhibitors and description of their properties is presented.
Due to their polymerization characteristics, hyper-branched dendrimers have lately shown to be pr... more Due to their polymerization characteristics, hyper-branched dendrimers have lately shown to be promising candidates for use in dental materials. In this study, a new dental adhesive system was prepared, using a dendrimer derived from 2-isocyanatoethyl methacrylate (G-IEMA), and its adhesive properties were investigated. The exposed dentin was treated with four universal adhesives (UAs): SBU (Scotchbond Universal™), FUT (Futurabond M+™), AE1 (experimental adhesive with Bis-GMA) and AE2 (experimental adhesive with G-IEMA), using Etch & Rinse (ER) or Self Etch (SE) protocols. Composite build-ups were prepared and stored for 24 h at 37 °C in distilled water. Composite/dentin beams were prepared with cross-sectional areas of 1 ± 0.3 mm2 and µTBS (Micro-tensile bond strength) test was performed at 0.5 mm/min. Failures modes were evaluated by stereomicroscopy, and bonding interfaces were observed by scanning electron microscopy (SEM). Statistical analysis of µTBS data was performed using G...
Introduction: A removable intraoral device is often manufactured in hard acrylic that is placed o... more Introduction: A removable intraoral device is often manufactured in hard acrylic that is placed over the incisal and occlusal surfaces of the teeth [1]. Currently the state of competitive anxiety is mostly observed as a specific situation constructed multidimensionally with a component both somatic and cognitive being that this situation affects the motor and cognitive performance of the athletes during the competition [2]. This study aimed to analyze the changes in the state of anxiety with the use of intraoral devices in Golf athletes. Materials and methods: After study approval by the Ethic Commission of the Cooperativa de ensino Egas Moniz, athletes from the Centro Nacional de Formac¸ão de Golfe do Jamor (CNFGJ) were invited to participate in this study. Following the informed consent a Diagnostic Criteria for Temporomandibular Disorder was applied. Inclusion criteria: Athletes of both genders who have signed informed consent with handicap <20 or professional. Exclusion criteria: Patients With TMD; Kennedy-Applegate Class I or II. In order to ensure anonymization all data were coded. Individualized intraoral devices (IOD) were developed for each athlete. Athletes held a 9-hole tournament with two phases: one phase without and another with the use of the IOD. To analyze the stress levels, it was requested the completion of the Competitive State Anxiety Inventory-II. Linear mixed effect models were used to evaluate the effect of the use the intraoral device, evaluation moment and interaction between them and the anxiety levels. Significance of these effects was assessed through the analysis of variance of type III with Kenward-Roger approximation for degrees of freedom. Results: The sample was composed of 8 athletes, with an average age of 27.3 (±7,32) years. The model developed to evaluate the effect of the IOD, evaluation season and their interaction on the anxiety state showed not to be significantly different from the null model (v 2 (3) ¼ 7.5918, p < 0.055). Discussion and conclusion: Statistically the use of IOD did not change in the subjective levels of anxiety, however the results need to be supported by larger and more significant samples CONTACT Pedro Cebola
Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia Maxilofacial
as resinas compostas. Existiram diferenç as estatisticamente significativas entre os valores inic... more as resinas compostas. Existiram diferenç as estatisticamente significativas entre os valores iniciais de rugosidade após polimento entre resinas compostas. Existiram, igualmente, diferenç as estatisticamente significativas entre os valores de rugosidade pós-escovagem entre as resinas compostas.
Currently, there is lack of human in vitro full tooth models that hold the odontoblast layer with... more Currently, there is lack of human in vitro full tooth models that hold the odontoblast layer with pulp tissue in their native environment. The appearance of new in vitro and in vivo models has provided new understanding of the potential of tissue engineering in dental pulp regeneration. However, the development of new in vitro full tooth models will allow us to get closer to in vivo conditions. Thus, the aim of this study is to preserve a living dentin-pulp complex, in a novel in vitro full crown model, after tooth extraction. Twenty intact third molars, after preparation, were divided into four groups, with five samples each. We placed the negative control samples (C) in saline, and the tested groups were placed (T) in supplemented DMEM, at two different times: 1 and 7 days. The specimens were processed for light microscopy observation. Contrary to C-groups, T-groups showed a functional dentin-pulp complex. The treated dentin-pulp complex presents normal histological appearance. Th...
Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia Maxilofacial, 2015
Introdução Ao longo dos anos, um dos principais objectivos tem sido o fabrico de resinas composta... more Introdução Ao longo dos anos, um dos principais objectivos tem sido o fabrico de resinas compostas com baixa contracção de polimerização e consequentemente menor stress de polimerização. 1,2,3,4 Neste sentido, vários fabricantes desenvolveram as resinas compostas bulk fill, que podem ser aplicadas em camadas de 4 mm, com polimerização aumentada e contracção controlada. 5 Objectivo Avaliar in-vitro a microinfiltração marginal, em restaurações de Classe II, efectuadas pela técnica directa, com resinas compostas de profundidade de polimerização aumentada. Resultados Após a observação e medição com a lupa estereoscópica, da penetração do corante, associada a cada grupo, os valores foram registados como demonstra a Tabela 1 Conclusão Este estudo demonstrou que nenhuma das resinas compostas de polimerização aumentada foi capaz de promover um selamento eficaz.
Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia Maxilofacial, 2015
Vários são os estudos sobre materiais dentários que usam dentes humanos previamente extraídos, os... more Vários são os estudos sobre materiais dentários que usam dentes humanos previamente extraídos, os quais são colocados em soluções de armazenamento de forma a prevenir a sua desidratação 1,2,3. No entanto, os meios em que os dentes são armazenados podem interferir nas propriedades físicas e ópticas dos mesmos, levando a alterações nos resultados dos estudos experimentais 4,5,6,7 .
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