Correlation between the event of the COVID-19 pandemic and symptoms of anxiety, depression and temporomandibular disorder in university students: cross-sectional study / Correlação entre o evento da pandemia de COVID-19 e sintomas de ansiedade, depressão e de disfunção temporomandibular em estudantes universitários: estudo transversal

ABSTRACT BACKGROUND AND OBJECTIVES: The COVID-19 pandemic has been shown to be a probable aggravator of psychological responses such as anxiety and depression. This study aimed to assess the correlation between symptoms of anxiety and depression during the COVID-19 pandemic and the existence of symptoms associated with temporomandibular dysfunction (TMD) in a Brazilian university population. METHODS: This epidemiological, cross-sectional clinical study evaluated its variables of interest using the COVID-19 Fear Scale, Hospital Anxiety and Depression Scale (HADS-A and HADS-D), Diagnostic Criteria for Temporomandibular Dysfunction (DC/TMD) and Oral Behavior Checklist (OBC) questionnaires. RESULTS: A total of 373 participants (females = 273) with a mean age of 23.8±5.45 years were included in this study. In addition, 78.2% of participants with anxiety symptoms and 54.5% of participants with depression symptoms reported a high level of TMD-related parafunction (p<0.01). The presence of anxiety symptoms increased the odds of developing intense fear of COVID-19 by 14.9 times (p<0.001) and the odds of developing moderate fear of COVID-19 by 3.5 times (p<0.001). The presence of an intense fear of COVID-19 increased the chances of developing anxiety symptoms by 17.15 times (p<0.001), while the presence of a moderate fear increased these chances by 3.12 times (p<0.001). In addition, the presence of intense (p=0.01) or moderate (p=0.018) COVID-19 fears increased the odds of developing TMD-related pain symptoms by 2.47 and 1.84 times, respectively, in this population. CONCLUSION: The presence of painful TMD symptoms was possibly influenced by fear of COVID-19. This, in turn, was related to the presence of anxiety and depression symptoms reported by the target population of this study.

RESUMO JUSTIFICATIVA E OBJETIVOS: A pandemia de COVID-19 mostrou-se um provável agravante de respostas psicológicas como ansiedade e depressão. Este estudo teve como objetivo avaliar a correlação entre sintomas de ansiedade e depressão durante o período da pandemia de COVID-19 e a existência de sintomas associados à disfunção temporomandibular (DTM) em uma população universitária brasileira. MÉTODOS: Este estudo clínico epidemiológico e transversal avaliou as suas variáveis de interesse por meio dos questionários Escala de Medo do COVID-19, Escala Hospitalar de Ansiedade e Depressão (HADS-A e HADS-D), Critérios Diagnósticos para Disfunção Temporomandibular (DC/DTM) e Checklist de Comportamentos Orais (OBC). RESULTADOS: Ao todo, 373 participantes (sexo feminino = 273), com média de idade de 23,8±5,45 anos foram incluídos neste estudo. Ademais, 78,2% dos participantes com sintomas de ansiedade e 54,5% dos participantes com sintomas de depressão reportaram alto nível de parafunção relacionada à DTM (p<0,01). A presença de sintomas de ansiedade aumentou em 14,9 vezes as chances de desenvolvimento de um quadro de medo intenso do COVID-19 (p<0,001) e de um quadro de 3,5 vezes nas chances de desenvolvimento de medo moderado do COVID-19 (p<0,001). A presença de um medo intenso do COVID-19 aumentou em 17,15 vezes as chances de desenvolvimento de sintomas de ansiedade (p<0,001), enquanto a presença de um medo moderado aumentou essas chances em 3,12 vezes (p<0,001). Ademais, a presença de medos intensos (p=0,01) ou moderados (p=0,018) do COVID-19 aumentou 2,47 e 1,84 vezes, respectivamente, as chances de desenvolvimento de sintomatologias dolorosas relacionadas à DTM nessa população. CONCLUSÃO: A presença dos sintomas dolorosos da DTM foi possivelmente influenciada pelo medo do COVID-19. Isso, por sua vez, esteve relacionado à presença de sintomas de ansiedade e de depressão, reportados pela população-alvo deste estudo.

Impact of chronic orofacial pain of temporomandibular disorder and anxiety on the academic performance of dental students / Impacto da dor orofacial crônica da disfunção temporomandibular e ansiedade no desempenho acadêmico de estudantes de odontologia

Introduction: The presence of chronic pain and mood disorders can be related to the performance of intellectual and technical tasks. Objective: This study evaluated the correlation between anxiety level, chronic orofacial pain of temporomandibular disorders (TMD), and academic performance in dental students. Methods: One hundred ninety-five students (74 men and 121 women) answered the Spielberger's trait­state anxiety inventory to evaluate the level of anxiety; the Research Diagnostic Criteria for TMD (RDC/TMD) was used to analyze chronic orofacial pain of TMD, and the academic performance was evaluated through the average grade of all college subjects concluded by the students. Correlations between the presence of chronic orofacial pain of TMD, trait, and state anxiety levels, chronic pain grade (CPG), chronic pain intensity (CPI), and academic performance were tested using Pearson's correlation test. Results: The mean age of the students was 21.8 years (SD=2.3). Chronic TMD was observed in 37.5% of the students. The majority of students had moderate trait and state anxiety. A significant correlation was observed between traitanxiety level and CPG (r=0.148, p=0.044), and CPI (r=0.187, p=0.009). No significant correlation was found between academic grade and presence of chronic pain of TMD (r=0.041, p=0.571), trait (r=0.079, p=0.273) and state-anxiety (r=0.107, p=0.136). Conclusion: The CPG and CPI increase in participants with higher trait-anxiety levels, however, no significant correlation was found between academic performance and trait/state anxiety or chronic orofacial pain of TMD.

Tratamento reabilitador de deformidade ocular: relato de caso / Treatment of eye deformity: a case report

O olho, responsável por um dos nossos cinco sentidos, é considerado a janela das nossas vidas, por onde observamos as paisagens, vivenciamos experiências e registramos as imagens. A ausência parcial ou total desse orgão pode acarretar problemas funcionais, estéticos, pessoais e sociais ao seu portador. Por se encontar na região da face, aréa considerada nobre para a identidade do indivíduo, a deformidade ocular acaba sendo muito constrangedora ao mesmo, dificultando sua interação com o próximo e afetando diretamente seus aspectos psicológicos. O objetivo deste trabalho é apresentar um relato de caso clínico de reabilitação com prótese ocular. Dessa forma foi realizado a seguinte sequência clínica: Moldagem da cavidade ocular, prova e ajustes da esclera artificial, pintura da íris artificial e instalação da prótese finalizada. O tratamento reabilitador possibilitou a restauração da harmonia facial e, com isso, devolveu a autoestima perdida do indivíduo, reinserindo-o à sociedade(AU)

The eye, responsible for one of our five senses, is considered the window of our lives, through which we observe the landscapes, experience and record the images. The partial or total absence of this organ can cause functional, aesthetic, personal and social problems to its bearer. Because it is found in the region of the face, which is considered noble for the identity of the individual, the eye deformity ends up being very embarrassing to it, making it difficult to interact with others and directly affecting their psychological aspects. The aim of this paper is to present a case report of rehabilitation with ocular prosthesis. Thus, the following clinical sequence was performed: Ocular cavity molding, testing and adjustments of the artificial sclera, painting of the artificial iris and installation of the finished prosthesis. The rehabilitative treatment enabled the restoration of facial harmony and, thus, returned the lost selfesteem of the individual, reinserting him to society(AU)

Anxiety and depression associated with pain and discomfort of temporomandibular disorders / Ansiedade e depressão associados à dor e desconforto das desordens temporomandibulares

ABSTRACT BACKGROUND AND OBJECTIVES: The etiology of temporomandibular disorders includes local and systemic factors, with an emphasis on the occlusal condition, trauma, parafunctional activities, and emotional stress, deriving signs of anxiety and depression. These, in turn, are more likely to develop in the university population, due to the changes required when entering university and the demand for good performance. This study aimed to evaluate the correlation between anxiety and depression symptoms and the existence of symptoms associated with temporomandibular disorders in university students. METHODS: An epidemiological, randomized, and cross-sectional clinical study conducted with 100 university students. The Research Diagnostic Criteria for Temporomandibular Disorders: Axis II and the Hospital Anxiety and Depression Scale questionnaires were applied. For the statistical analysis, the Chi-square tests and the Logistic regression model were used. RESULTS: The results of the present study consisted of responses from 79 women and 21 men, with a mean age of 19 years. The following associations were observed: general health status and depression; anxiety and pain in the face/ clicking; habit of grinding/clenching teeth when sleeping, and a "yes" answer to anxiety; discomfort with your teeth and depression; state of anguished/worried about all anxiety issues; depression and thoughts about death, difficulty in breathing and feeling discouraged about the future. CONCLUSION: From the data obtained, it was possible to conclude that the presence of symptoms related to anxiety and depression interfere with the painful symptoms of temporomandibular disorders in the addressed population.

RESUMO JUSTIFICATIVA E OBJETIVOS: A etiologia das disfunções temporomandibulares engloba fatores locais e sistêmicos, destacando-se a condição oclusal, trauma, atividades parafuncionais e estresse emocional, derivando-se os sinais de ansiedade e de depressão. Esses, por sua vez, apresentam maior propensão em se desenvolver na população universitária devido às mudanças exigidas ao ingressar na universidade e a cobrança por um bom desempenho. O objetivo deste estudo foi avaliar a correlação de sintomas de ansiedade e de depressão e a existência de sintomas associados às disfunções temporomandibulares em estudantes universitários. MÉTODOS: Realizou-se um estudo clínico epidemiológico, aleatório e transversal, cuja amostra foi constituída por 100 estudantes universitários, aos quais foram aplicados os questionários Research Diagnostic Criteria for Temporomandibular Disorders: Eixo II e o Hospital Anxiety and Depression Scale. Para a análise estatística foram utilizados os testes Qui-quadrado e o Modelo de regressão logística. RESULTADOS: Os resultados do presente estudo foram constituídos pelas respostas de 79 mulheres e 21 homens, com média de idade de 19 anos. Foram observadas as seguintes associações: estado de saúde geral e depressão, ansiedade e dor na face/estalos, hábito de ranger/apertar os dentes ao dormir, e resposta "sim" para ansiedade, desconforto com seus dentes e depressão; estado de angustiado/preocupado com todas as questões de ansiedade; depressão e pensamentos sobre morte, dificuldade em respirar e sentir-se desanimado sobre o futuro. CONCLUSÃO: A partir dos dados obtidos foi possível concluir que a presença de sintomas relativos à ansiedade e depressão interferem nos sintomas dolorosos das disfunções temporomandibulares da população abordada.

Reabilitação de paciente maxilectomizado por meio de prótese parcial removível obturadora palatina / Maxilectomized patient rehabilitation with removable partial palatal obturator prosthesis

Este trabalho tem como objetivo apresentar o protocolo de reabilitação por meio de prótese obturadora palatina, preconizado pela Universidade Federal de Alfenas (UNIFAL-MG), através do relato de um caso clínico de paciente maxilectomizada. A paciente apresentava comunicação buco-sinu-nasal e ausência parcial de dentes maxilares e mandibulares. Foi realizada moldagem de estudo, obtenção do modelo de trabalho, delineamento, planejamento das armações metálicas, preparos específicos, moldagem de trabalho e obtenção das armações; que foram provadas, os registros intermaxilares tomados, modelos montados em articulador e selecionados os dentes artificiais. Foi realizada prova estética e funcional com ênfase na pronúncia em função da existência de comunicação. Foi selecionada a cor da base e as próteses foram instaladas. Conclui-se que a prótese obturadora constitui um método satisfatório para a reabilitação de defeitos palatinos, pois proporcionou o vedamento da comunicação, proteção aos tecidos da área afetada, melhoras funcionais e estéticas, favorecendo a reintegração da paciente ao convívio social(AU)

The purpose of this study was the proposal of the clinical therapy and treatment of prosthetic patient under the Federal University of Alfenas (UNIFAL-MG), using a clinical report of a maxilectomized patient. The patient presented buco-sinu-nasal communication and partial absence of maxillary and mandibular teeth. It was made the study impression, obtaining the working model, designing, planning of metal frames, specific preparation, working impression and obtaining frames were carried out; which were tested, taken intermaxillary records, articulator mounted models and selected artificial teeth. Aesthetic and functional tests were performed with emphasis on pronunciation as a function of the existence of communication. The color of the base was selected and the prostheses were installed. It was concluded that the obturator prosthesis is a satisfactory method for the rehabilitation of palatal defects, since it provided the seal of communication, protection to the tissues of the affected area, functional and aesthetic improvements, favoring the reintegration of the patient to social interaction(AU)

Effect of different methods of hygiene on the color stability of extrinsically pigmented facial silicone

Evaluate the color stability of facial silicone pigmented extrinsically under the influence of the hygiene process. Methods: 160 samples were prepared and divided into 8 groups (n = 20) according to the pigmentation technique used: Group 1: Colorless silicone; Group 2: Pigmented exclusively with oil ink; Group 3: Pigmented with oil ink + opacifier; Group 4: Colorless, applying Prime; Group 5: Pigmented with oil ink covered with Prime; Group 6: Pigmented with oil ink + opacifier and covered with Prime; Group 7: Pigmented with oil ink diluted in Prime; Group 8: Pigmented with oil ink + opacifier diluted in Prime. Then the samples were distributed into two subgropus (n=10): 1: neutral soap and 2: 1% hypochlorite solution. The color readings occurred in the initial period and 60 days after the hygiene procedures. For this, it was used a spectrophotometer reflection and CIE-Lab program. The data was tabulated and submitted to analysis of variance (ANOVA) followed by Tukey test (p <0.05). Results: The groups of samples disinfected with soap showed significantly lower color change values than those presented by the samples disinfected with hypochlorite. The best results were presented by the group of samples pigmented with oil ink diluted in prime and sanitized with neutral soap (ΔE=1.21, without opacifier and ΔE=0.82, with opacifier). Conclusions: The association of oil ink diluted in prime and hygiene technique with soap promotes the lower color change of facial silicone pigmented extrinsically

Influência da pigmentação, técnica de união e envelhecimento acelerado sobre a resistência de união entre resina acrílica e silicone facial / Influence of nanoparticles pigments, adhesive system and accelerated aging on the bond strength between the acrylic resin and facial silicone

Próteses maxilofaciais retidas por implantes necessitam de uma infraestrutura acrílica, na qual ficam contidos os sistemas de retenção; contudo, a união resina acrílica-silicone facial não é estável. Assim, este estudo teve como objetivo avaliar a influência da pigmentação com nanopartículas, técnica de união e envelhecimento acelerado sobre a resistência de união entre resina acrílica e silicone facial. Para tal, foram confeccionadas 960 amostras que consistiam em uma barra de resina acrílica de ativação química aderida ao silicone facial Silastic MDX 4-4210 incolor ou pigmentado com nanopartículas (tinta a óleo e/ou opacificador a base de sulfato de bário). A adesão entre os dois materiais foi feita pela simples deposição do silicone sobre a resina acrílica (N); por retenções mecânicas, representadas por ranhuras (R); aplicação do primer de uso médico (DC 1205 Prime - DC); primer para material reembasador (Sofreliner Primer MS- SF) ou adesivo de uso médico (Silatic Medical Adhesive Type A - A) isolados ou associados. Desta maneira, as amostras foram divididas em 4 grupos (n=240), de acordo com a nanopartícula adicionada ou não, sendo Grupo 1: Incolor; Grupo 2: Tinta a óleo; Grupo 3: Opacificador; e Grupo 4: Tinta a óleo e opacificador. Estes grupos foram divididos em 12 subgrupos (n=20), de acordo com o meio utilizado para unir a resina acrílica ao silicone, sendo: Subgrupo I: N; Subgrupo II: A; Subgrupo III: DC; Subgrupo IV: DC+A; Subgrupo V: SF; Subgrupo VI: SF+A; Subgrupo VII: R; Subgrupo VIII: R+A; Subgrupo IX: R+DC; Subgrupo X: R+DC+A; Subgrupo XI: R+SF; Subgrupo XII: R+SF+A. Metade das amostras de cada subgrupo (n=10) foi submetida ao ensaio de resistência de união no período inicial, em uma Máquina de Ensaios Universal, com velocidade de tração constante de 10mm/min, até que ocorresse a falha. As amostras restantes foram expostas ao envelhecimento acelerado por 1008 horas e, em seguida, submetidas ao teste de tração. Após a realização do teste, os...

Maxillofacial prosthesis retained by implants use an acrylic framework to fit the attachment systems. However, the bond between acrylic resin and facial silicone is instable. Therefore, this study investigated the influence of nanoparticles pigments, adhesive system and accelerated aging on the bond strength between the acrylic resin and facial silicone. A total of 960 specimens made of selfpolymerized acrylic resin bar adhered to Silastic MDX 4-4210 facial silicone either colorless or pigmented with nanoparticles (oil tint and/or barium sulfate opacifier) were fabricated. The union between the two materials was performed in different ways: no treatment on the acrylic bar (N), mechanical retentions represented by scratches (R), application of prime for medical use (DC 1205 Prime - DC), primer for soft liner material (Sofreliner Primer MS - SF), and adhesive for medical use (Silastic Medical Adhesive Type A - A) alone or in combinations. The specimens were divided into 4 groups (n=240) according to the nanoparticle presence: Group 1: colorless; Group 2: oil tint; Group 3: opacifier; and Group 4: oil tint and opacifier. These groups were divided into 12 subgroups (n=20) according to the surface treatment used to bond the facial silicone to the acrylic resin: Subgroup I: N; Subgroup II: A; Subgroup III: DC; Subgroup IV: DC+A; Subgroup V: SF; Subgroup VI: SF+A; Subgroup VII: R; Subgroup VIII: R+A; Subgroup IX: R+DC; Subgroup X: R+DC+A; Subgroup XI: R+SF; Subgroup XII: R+SF+A. Half of the specimens of each subgroup (n=10) were subjected to bond strength test at the baseline period in a universal testing machine at a crosshead speed of 10 mm/min until failure. The other specimens were exposed to the accelerated aging during 1008 hours and then subjected to the bond test. The force values to failure the bond between acrylic resin and facial silicone were recorded and the bond interface was characterized according to the failure type: adhesive, cohesive or mixed...

Influência da pigmentação, técnica de união e envelhecimento acelerado sobre a resistência de união entre resina acrílica e silicone facial / Influence of nanoparticles pigments, adhesive system and accelerated aging on the bond strength between the acrylic resin and facial silicone

Próteses maxilofaciais retidas por implantes necessitam de uma infraestrutura acrílica, na qual ficam contidos os sistemas de retenção; contudo, a união resina acrílica-silicone facial não é estável. Assim, este estudo teve como objetivo avaliar a influência da pigmentação com nanopartículas, técnica de união e envelhecimento acelerado sobre a resistência de união entre resina acrílica e silicone facial. Para tal, foram confeccionadas 960 amostras que consistiam em uma barra de resina acrílica de ativação química aderida ao silicone facial Silastic MDX 4-4210 incolor ou pigmentado com nanopartículas (tinta a óleo e/ou opacificador a base de sulfato de bário). A adesão entre os dois materiais foi feita pela simples deposição do silicone sobre a resina acrílica (N); por retenções mecânicas, representadas por ranhuras (R); aplicação do primer de uso médico (DC 1205 Prime - DC); primer para material reembasador (Sofreliner Primer MS- SF) ou adesivo de uso médico (Silatic Medical Adhesive Type A - A) isolados ou associados. Desta maneira, as amostras foram divididas em 4 grupos (n=240), de acordo com a nanopartícula adicionada ou não, sendo Grupo 1: Incolor; Grupo 2: Tinta a óleo; Grupo 3: Opacificador; e Grupo 4: Tinta a óleo e opacificador. Estes grupos foram divididos em 12 subgrupos (n=20), de acordo com o meio utilizado para unir a resina acrílica ao silicone, sendo: Subgrupo I: N; Subgrupo II: A; Subgrupo III: DC; Subgrupo IV: DC+A; Subgrupo V: SF; Subgrupo VI: SF+A; Subgrupo VII: R; Subgrupo VIII: R+A; Subgrupo IX: R+DC; Subgrupo X: R+DC+A; Subgrupo XI: R+SF; Subgrupo XII: R+SF+A. Metade das amostras de cada subgrupo (n=10) foi submetida ao ensaio de resistência de união no período inicial, em uma Máquina de Ensaios Universal, com velocidade de tração constante de 10mm/min, até que ocorresse a falha. As amostras restantes foram expostas ao envelhecimento acelerado por 1008 horas e, em seguida, submetidas ao teste de tração. Após a realização do teste, os...

Maxillofacial prosthesis retained by implants use an acrylic framework to fit the attachment systems. However, the bond between acrylic resin and facial silicone is instable. Therefore, this study investigated the influence of nanoparticles pigments, adhesive system and accelerated aging on the bond strength between the acrylic resin and facial silicone. A total of 960 specimens made of selfpolymerized acrylic resin bar adhered to Silastic MDX 4-4210 facial silicone either colorless or pigmented with nanoparticles (oil tint and/or barium sulfate opacifier) were fabricated. The union between the two materials was performed in different ways: no treatment on the acrylic bar (N), mechanical retentions represented by scratches (R), application of prime for medical use (DC 1205 Prime - DC), primer for soft liner material (Sofreliner Primer MS - SF), and adhesive for medical use (Silastic Medical Adhesive Type A - A) alone or in combinations. The specimens were divided into 4 groups (n=240) according to the nanoparticle presence: Group 1: colorless; Group 2: oil tint; Group 3: opacifier; and Group 4: oil tint and opacifier. These groups were divided into 12 subgroups (n=20) according to the surface treatment used to bond the facial silicone to the acrylic resin: Subgroup I: N; Subgroup II: A; Subgroup III: DC; Subgroup IV: DC+A; Subgroup V: SF; Subgroup VI: SF+A; Subgroup VII: R; Subgroup VIII: R+A; Subgroup IX: R+DC; Subgroup X: R+DC+A; Subgroup XI: R+SF; Subgroup XII: R+SF+A. Half of the specimens of each subgroup (n=10) were subjected to bond strength test at the baseline period in a universal testing machine at a crosshead speed of 10 mm/min until failure. The other specimens were exposed to the accelerated aging during 1008 hours and then subjected to the bond test. The force values to failure the bond between acrylic resin and facial silicone were recorded and the bond interface was characterized according to the failure type: adhesive, cohesive or mixed...

Bond strength between acrylic resin and maxillofacial silicone

The development of implant dentistry improved the possibilities of rehabilitation with maxillofacial prosthesis. However, clinically it is difficult to bond the silicone to the attachment system. OBJECTIVES: This study aimed to evaluate the effect of an adhesive system on the bond strength between acrylic resin and facial silicone. MATERIAL AND METHODS: A total of 120 samples were fabricated with auto-polymerized acrylic resin and MDX 4-4210 facial silicone. Both materials were bonded through mechanical retentions and/or application of primers (DC 1205 primer and Sofreliner primer S) and adhesive (Silastic Medical Adhesive Type A) or not (control group). Samples were divided into 12 groups according to the method used to attach the silicone to the acrylic resin. All samples were subjected to a T-peel test in a universal testing machine. Failures were classified as adhesive, cohesive or mixed. The data were evaluated by the analysis of variance (ANOVA) and the Tukey's HSD test (α=.05). RESULTS: The highest bond strength values (5.95 N/mm; 3.07 N/mm; 4.75 N/mm) were recorded for the samples that received a Sofreliner primer application. These values were significantly higher when the samples had no scratches and did not receive the application of Silastic Medical Adhesive Type A. CONCLUSIONS: The most common type of failure was adhesive. The use of Sofreliner primer increased the bond strength between the auto-polymerized acrylic resin and the Silastic MDX 4-4210 facial silicone.

Hardness evaluation of prosthetic silicones containing opacifiers following chemical disinfection and accelerated aging

We evaluated the effects of disinfection and aging on the hardness of silicones containing opacifiers and intended for use in facial prosthetics. A total of 90 samples were produced using a cylindrical metal mold 3 mm in height and 30 mm in diameter. The samples were fabricated from Silastic MDX 4-4210 silicone in three groups: GI contained no opacifier, GII contained barium sulfate (Ba), and GIII contained titanium dioxide (Ti). The samples were disinfected using effervescent tablets (Ef), neutral soap (Ns), or 4 percent chlorhexidine (Cl) 3 times a week for 60 days. After this period the samples underwent 1,008 hours of accelerated aging. The hardness was measured using a durometer immediately following the disinfection period and after 252, 504, and 1,008 hours of aging. The data were statistically analyzed using 3-way ANOVA and the Tukey test (p < .05). The GIII group exhibited the greatest variation in hardness regardless of elapsed time. All groups displayed greater hardness after 1,008 hours of accelerated aging independent of disinfectant type. All of the hardness values were within the clinically acceptable range.

Effect of accelerated aging on the microhardness and color stability of flexible resins for dentures

Acrylic resins have been widely used due to their acceptable esthetics and desirable characteristics such as easy handling, good thermal conductivity, low permeability to oral fluids and color stability. Flexible resins were introduced on the market as an alternative to the use of conventional acrylic resins in the construction of complete and partial removable dentures. Although these resins present advantages in terms of esthetics and comfort, studies assessing chromatic and microhardness alterations of these materials are still scarce in the related literature. The aim of this study was to evaluate the chromatic and microhardness alterations of two commercial brands of flexible resins in comparison to the conventional resin Triplex when submitted to accelerated aging. The resins were manipulated according to manufacturers' instructions and inserted into a silicone matrix to obtain 21 specimens divided into 3 groups: Triplex, Ppflex and Valplast. Triplex presented the highest microhardness value (p < 0.05) for all the aging periods, which was significantly different from that of the other resins, followed by the values of Valplast and Ppflex. Comparison between the flexible resins (Ppflex and Valplast) revealed a statistically significant difference (p < 0.05) as regards color. The flexible resin Ppflex and the conventional resin Triplex presented no statistically significant difference (p < 0.05) as regards aging. The accelerated aging significantly increased the microhardness values of the resins, with the highest values being observed for Triplex. Valplast presented the greatest chromatic alteration after accelerated aging.

Efeito da desinfecção química e do envelhecimento acelerado sobre a estabilidade dimensional, reprodução e manutenção de detalhes e estabilidade de cor do silicone facial Silastic MDX 4-4210 com opacificador / Effect of chemical disinfection and accelerated aging, on the dimensional stability, details reproduction and color stability of Silastic MDX 4-4210 facial prosthesis silicon with opacifier

Este estudo teve como objetivo avaliar a estabilidade dimensional, reprodução de detalhes e estabilidade de cor de silicone facial, com adição ou não de pigmento e opacificador; sob influência da desinfecção química e do envelhecimento acelerado. Para isso, foram obtidas 120 amostras, utilizando o silicone Silastic MDX 4-4210, divididas em 4 grupos contendo 30 amostras cada, sendo GI - incolor, GII - pigmentado com pó de cerâmica, GIII – com adição de sulfato de bário (opacificador) e GIV- pigmentado com pó de cerâmica e sulfato de bário. Dez amostras de cada grupo foram desinfetadas com uma das três substâncias a seguir: pastilhas efervescentes a base de peróxido alcalino, sabão neutro ou clorexidina. O processo de desinfecção química foi realizado três vezes por semana, durante 60 dias. Após esse período, todas as amostras foram submetidas ao envelhecimento acelerado. Os testes de estabilidade dimensional, reprodução de detalhes e estabilidade de cor foram realizados no período inicial, após 60 dias de desinfecção e, nos intervalos de 252, 504 e 1008 horas de envelhecimento acelerado. As amostras foram analisadas em computador pelo sistema AutoCAD para verificação da alteração dimensional linear; e observadas em lupa estereoscópica para a análise da reprodução de detalhes. A estabilidade de cor foi verificada por meio de espectrofotometria de reflexão. Os valores obtidos nos testes de estabilidade dimensional e estabilidade cromática foram submetidos à análise de variância e teste de Tukey (p<0,05). Para a análise da reprodução e manutenção de detalhes foi utilizado escore de 0 a 2. O fator desinfecção não influenciou estatisticamente nos valores de estabilidade dimensional, reprodução de detalhes e estabilidade de cor do silicone, independente da pigmentação. O envelhecimento acelerado provocou redução significativa nos valores de estabilidade dimensional após o período de 1008 horas, independente do desinfetante e da pigmentação. Quanto à reprodução de...

The aim of this study was to evaluate the dimensional stability, reproduction and maintenance of details and color stability of facial silicone, with different pigmentation, on the influence of the disinfection and accelerated aging. 120 samples were obtained, using Silastic MDX 4-4210 elastomer, divided in 4 groups with 30 samples: GI - colorless, GII - pigmented with ceramics, GIII - pigmented with barium sulfate opacifier, and GIV - pigmented with ceramics and barium sulfate opacifier. Ten samples of each group was submitted to the disinfection with effervescent tablets, with neutral soap or 4% chlorhexidine, three times a week during 60 days. After this period all samples were taken to a chamber of accelerated aging for not metallic bodies. The tests of dimensional stability, maintenance of the details, and color stability were realized after the confection, disinfection and in the intervals of each cycle of accelerated aging (252, 504 e 1008 hours). Samples were analyzed, in computer by the AutoCAD system to verification of the linear dimensional alteration and observed, in stereoscopic magnifying glass for analysis of the reproduction of details. The color stability was analyzed by means of spectrophotometer. The dimensional alteration and color stability values had been submitted to the analysis of variance and Tukey test (p<0.05). For the analysis of detail reproduction, the 0 -2 scores were used It can be observed that the factor: chemical disinfection had no influenced statistically on dimensional stability, detail reproduction and color stability values. Accelerated aging had influenced statistically on dimensional stability values after 1008 hours. About detail reproduction, all samples exhibited score 2 for all analyzed periods. Pigment and opacifier association was more stable for chromatic stability test in all analyzed periods. GIV group presented the best results for all disinfectant and accelerated aging periods. All values obtained are...

Avaliação da microdureza superficial de quatro diferentes resinas acrílicas para base de dentaduras / Evaluation of superficial microhardness of four different acrylic resins for dentadure bases

O objetivo deste trabalho foi avaliar a microdureza superficial de quatro tipos de resinas acrílicas (Onda Cryl, Vipi Wave, Vipi Cril e QC-20 com polimerização convencional e com polimerização por energia de microondas) para base de dentaduras, em função do período de armazenagem, em água, de seis meses. Foram confeccionadas vinte e cinco amostras, as quais foram fixadas em discos acrílicos incolores, devidamente identificados, que foram então polidas em uma politriz e foram submetidas ao teste de microdureza superficial Knoop em um microdurômetro digital (modelo HMV-2T) e posteriormente armazenados em água destilada a 35 ± 2°C por seis meses, após o qual um segundo teste de microdureza superficial das amostras foi realizado. Os resultados obtidos foram submetidos à análise de variância e ao teste de Tukeyao nível de significância de 5%. Observou-se que o fator tempo de armazenagem promoveu um decréscimo dos valores médios de microdureza superficial Knoop para todos os grupos estudados, sendo que apenas para os grupos Vipi Cril e QC-20 polimerizado por energia de microondas esta diminuição dos valores foi estatisticamente significativa.