Insertion methods and gap/void formation in atraumatic restorative technique: A micro-CT analysis

Abstract Wetting the dentin is critical to atraumatic restorative treatment. The conventional insertion can be challenging when using high-viscosity glass-ionomer cement. This study evaluated the formation of gaps and voids after three insertion methods using micro-CT. Teeth underwent removal of occlusal and proximal caries through the atraumatic restorative treatment technique. Then, they were fixed in an artificial dental arch to simulate the clinical condition and were restored using three insertion methods: conventional, Centrix injection, and double-filling. Previous dentin conditioning procedures, steel matrix and wooden wedge application, and post-insertion procedures (digital compression and surface protection) were the same. The material was inserted using a manual instrument in the conventional technique and was inserted with a syringe in the Centrix injection group. In the double-filling technique, the tooth received a first layer of a flowable ionomer (through modifying the powder/liquid ratio), and a second layer (with standard ratio) was applied before the final set of the first one. A micro-CT unit scanned each tooth before and after restoration. Each cavity was defined as the volume of interest, and the volumes of gaps and voids were calculated. Data were analyzed using one-way ANOVA and Tukey posthoc test (p < .05). Double-filling had improved filling volume with lower values for gap volume, followed by Centrix injection. The conventional technique had the highest gap volume. No statistically significant difference was observed for void volume. Double-filling demonstrated fewer gaps, followed by Centrix injection, which is critical to obtain better adhesive, remineralizing, and antibacterial activities.

Resumo O molhamento da dentina parcialmente desmineralizada no fundo da cavidade dentária é fundamental para o sucesso do tratamento restaurador atraumático. No entanto, o método de inserção convencional pode ser desafiador ao usar cimento de ionômero de vidro de alta viscosidade. Este estudo avaliou a formação de gaps e vazios internos após três métodos de inserção de cimento de ionômero de vidro de alta viscosidade usando micro-CT. Dez terceiros molares foram submetidos à remoção de cárie oclusal através da técnica de tratamento restaurador atraumático e complementação proximal (com ou sem lesão pré-existente). Em seguida, foram fixados em uma arcada dentária artificial para simular a condição clínica. Os dentes foram restaurados usando a técnica de tratamento restaurador atraumático com três métodos de inserção: convencional, injeção Centrix e dupla inserção. Os procedimentos anteriores de condicionamento dentinário, inserção de matriz de aço, aplicação de cunha de madeira e procedimentos pós-inserção do material (como compressão digital e proteção de superfície) foram os mesmos para os três grupos testados. O material foi inserido com instrumento manual na técnica convencional, seguindo a metodologia clássica do tratamento restaurador atraumático. O material foi inserido com um dispositivo desenvolvido especificamente para esse fim na técnica de inserção com seringa tipo Centrix. Na técnica de dupla obturação, o dente recebeu uma primeira camada do cimento de ionômero de vidro mais fluido (obtido através da modificação da relação pó/líquido), e uma segunda camada (com relação pó/líquido padrão) foi aplicada antes da presa final da primeira. Um micro-CT escaneou cada dente antes e depois da restauração. Cada cavidade foi definida como o volume de interesse, e os volumes de gaps e vazios foram calculados. Os dados foram analisados por ANOVA one-way e teste post-hoc de Tukey com nível de significância de 5%. A dupla inserção melhorou significativamente o volume de preenchimento com valores percentuais mais baixos para o volume do gap, seguido pela injeção com seringa tipo Centrix. A técnica convencional apresentou o maior percentual de volume de gap. Nenhuma diferença estatisticamente significativa foi observada para o volume de vazios internos. O grupo de dupla inserção demonstrou menor formação de gaps, seguido pelo grupo de injeção com seringa tipo Centrix, que é fundamental para obter melhores atividades adesivas, remineralizantes e antibacterianas.

X-Ray Microtomography Analysis of Gaps and Voids in the Restoration of Non-Carious Cervical Lesions with Different Composite Resins

Context (Background): Resin composites are the most widely used material for restoring cervical defects. However, the high failure rate of these restorations is still a concern. Aims: The aim of this in vitro study was to evaluate, using microtomography (?CT), the interfacial gap and voids formation in Class V cavities in premolars restored with materials with lower polymerization shrinkage combined with different restorative techniques. Settings and Design: Cervical defects were created in 30 intact premolar and were randomly distributed to be restored by one of the following techniques (n = 6): Composite resin with two increments (CR), organic modified polymer (ORMOCER) with single (OR1) or two increments (OR2, or low viscosity bulk?fill composite resin with single (BF1) or two increments (BF2). Methods and Material: Each tooth was scanned before filling to determine the volume of interest (VOI) to be applied in the second ?CT after restoration and to control the cavity volume among the groups. In the ?CT after filling, the volume of interfacial gaps and voids was calculated for each group. Statistical Analysis: The groups were compared using one?way and Tukey HSD post hoc test (? = 0.05). Results: It was possible to identify higher gap formation in the OR1 group and higher void formation in CR group (P < 0.05). OR2 group showed better results than the group with one increment. BF2 showed the best filling capacity. Conclusions: It was possible to conclude that the material and the number of increments directly influenced the internal adaptation and voids formation of Class V restorations.

Cytotoxicity, and antimicrobial and physicochemical properties of sealers incorporated with Uncaria tomentosa

Abstract This study evaluated the cytotoxicity, the antimicrobial and physicochemical properties of root canal sealers incorporated with phytotherapic Uncaria tomentosa (UT). Unmodified AH Plus (Dentsply, DeTrey, Germany) and MTA Fillapex (Angelus, Londrina, Brazil) were used as controls. UT was incorporated into AH Plus and MTA Fillapex, at concentrations of 2% and 5% of the total weight of these sealers (w/w). Flowability, setting time, and solubility were evaluated following ISO requirements. The pH values were measured at periods of 12, 24, 48 hours, and 7 days. The antimicrobial activity of the sealers against Enterococcus faecalis was analyzed by both direct contact tests in freshly prepared sealers, and after 7 days. The cytotoxicity of the samples was evaluated by the MTT assay, to check Balb/c 3T3 cell viability. The statistical analysis was performed by one-way ANOVA and Tukey's test (p < 0.05). The incorporation of UT was associated with a decrease in flow, for both sealers, an increase in AH Plus setting time, increase in MTA Fillapex pH values, and solubility (after 14 days), for both sealers (p < 0.05). Regarding the antibacterial evaluation, bacterial reduction was reported after incorporation of UT into both AH Plus and MTA Fillapex, up to 7 days after handling of the material (P<0.05). UT incorporation decreased the cytotoxic effects of both AH Plus and MTA Fillapex sealers in a way directly proportional to their respective concentrations (p < 0.05). In conclusion, UT can be added to both sealers to reduce their cytotoxicity, and improve their antibacterial effects, without compromising their original physicochemical properties.

Resistência de união à dentina de um material fotopolimerizável à base de silicato de cálcio e modificado por resina / Dentin bond strength of resin-modified light-curable calcium-silicate-based material

Objetivo: este estudo teve como objetivo comparar a resistência de união à dentina de um material à base de silicato de cálcio fotopolimerizável modificado por resina (TheraCal LC®; Bisco, Schaumburg, IL, EUA) com MTA branco (WMTA®; Angelus, Londrina, PR, Brasil). Materiais e Métodos: dezesseis incisivos superiores e caninos humanos foram selecionados e três discos de 1 mm foram obtidos a partir do terço médio de cada raiz. Na superfície coronal de cada disco, dois furos de 1,2 mm de largura foram perfurados na dentina. Em seguida, os buracos artificiais foram preenchidos com um dos materiais testados: WMTA® e TheraCal LC®. As fatias dentárias preenchidas foram armazenadas em uma solução salina tamponada com fosfato (PBS) (pH 7,2) por 7 dias a 37°C. Depois disso, a avaliação do push-out foi realizada com uma ponta do êmbolo de 1,0 mm. A carga foi aplicada a uma velocidade de 0,5 mm / min até o deslocamento do selador. Os resultados foram expressos em MPa. O teste U de Mann-Whitney foi aplicado para classificar os materiais quanto à resistência adesiva à dentina. O nível de significância foi estabelecido em = 5%. Resultados: todas as amostras apresentaram resultados de resistência de união à dentina mensuráveis e não ocorreram falhas prematuras. O TheraCal LC® demonstrou valores superiores de resistência de união à dentina quando comparado ao WMTA® (P<0,0001). Conclusões: existe uma vantagem do TheraCal LC® sobre o WMTA® no que diz respeito à resistência da união ao empurrar e, portanto, pode ser considerado um material reparador promissor e inovador

Objective: this study aimed to compare the dentin bond strength of a resin-modified light-curable calcium-silicate-based material (TheraCal LC®; Bisco, Schaumburg, IL, USA) with White MTA (WMTA®; Angelus, Londrina, PR, Brazil). Materials and Methods: sixteen human maxillary incisors and canines were selected and three 1-mm-discs were obtained from the middle third of each root. On the coronal surface of each disc, two 1.2-mm-wide-holes were drilled through the dentin. Then, artificial holes were filled with one of the tested materials: WMTA® and TheraCal LC®. The filled dental slices were stored in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days at 37°C. After that, push-out assessment was performed with a 1.0-mm-plunger-tip. Load was applied at a crosshead speed of 0.5 mm/min until sealer displacement. The results were expressed in MPa. Mann-Whitney U test was applied to rank materials regarding dentin push-out bond strength. Significance level was set at a = 5%. Results: All specimens showed measurable results and no premature failure occurred. TheraCal LC® demonstrated superior push-out bond strength values to dentin when compared to WMTA® (P<0.0001). Conclusions: there is advantage of TheraCal LC® over WMTA® as regards to the push-out bond strength and, therefore it may be taken as a promising and innovative reparative material

Implantes, componentes e os honorários profissionais: o que agrega mais no custo final da Implantodontia? Análise de custos entre seis marcas comercialmente disponíveis no Brasil / Dental implants, components, and professional fees: what is most signifi cant factor in the overall cost of Brazilian implant dentistry? A cost analysis among six different commercially available brands

Objetivo: sistematizar e organizar o conjunto de informações relacionadas ao planejamento e manejo de custos na área de Implantodontia. Material e métodos: uma reabilitação mandibular (prótese total implantorretida com carregamento imediato e ancorada por cinco implantes) foi utilizada como referência para custos. Para determinação do valor total, foram somados os honorários e os custos do profissional com o consultório, com componentes cirúrgicos e protéticos para execução do caso, além dos custos laboratoriais. O custo total foi acrescido em 20% devido à taxa de risco do tratamento. Seis marcas comerciais foram selecionadas para realização dos orçamentos. Os valores de todos os componentes em moda corrente (Reais) foram expostos baseados em um denominador comum (X). Ainda, as porcentagens de custo de cada componente segundo o tipo de cilindro selecionado também foram descritas. Resultados: o valor do tratamento conforme o sistema de implantes variou entre 64,4 X e 209,6 X. No custo fi nal, a variação ficou entre 243,1 X e 441,4 X. Conclusão: embora este trabalho não tenha englobado no custo as sessões de retorno para acompanhamento e higienização, fratura de pilares protéticos e parafusos, perda de implantes e a fratura de dentes artificiais, a maior variação nos valores do tratamento refere-se aos sistemas de implantes selecionados. Entretanto, o uso de cilindros calcináveis ou de cilindros com base metálica não interferiu significativamente no custo total, o que favorece a postura clínica de utilizar componentes com partes pré-fabricadas para aliviar os problemas biológicos na interface implante/prótese.

Objective: to organize the information related to treatment and cost management for Implant Dentistry. Material and methods: a mandibular restoration (a five implant-retained prosthesis under immediate loading) was used as reference for cost analysis. To determine the overall value, professional, surgical, prosthetic component, and laboratory costs were added. The overall cost was increased in 20% due to the treatment risk. Six different commercial manufacturers were selected to present the costs. The values in the real currency (BRL) were converted to a common denominator (X). Also, the cost percentages associated to each prosthetic cylinder were also described. Results: the overall treatment value according to each implant system ranged from 64.4 X to 209.6 X. For the overall cost, the variation was between 243.1 and 44.1 X. Conclusion: although recall sessions have not been included in this paper (e.g. hygiene maintenance, abutment screw fracture/ loosening, implant loss, and artifi cial tooth fracture events), the great cost variation relates to the choice of the dental implant system. However, the use of pre-fabricated or plastic burnout cylinders did not signifi cantly interfere in the overall cost, which favors the use of pre-fabricated parts to alleviate the biological issues at the implant-prosthesis interface.

Push-out bond strength of MTA HP, a new high-plasticity calcium silicate-based cement

Abstract This study was designed to investigate the resistance to dislodgment provided by MTA HP, a new high-plasticity calcium silicate-based cement. Biodentine and White MTA Angelus were used as reference materials for comparison. Three discs 1 ± 0.1 mm thick were obtained from the middle third of the roots of 5 maxillary canines. Three 0.8-mm-wide holes were drilled on the axial surface of each root disc. Standardized irrigation was performed. Then the holes were dried with paper points and filled with one of the three tested cements. The filled dental slices were immersed in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days before the push-out assessment. The Kruskal-Wallis test was applied to assess the effect of each endodontic cement on the push-out bond strength. Mann-Whitney with Bonferroni correction was used to isolate the differences. The alpha-type error was set at 0.05. All specimens had measurable push-out values and no premature failure occurred. There were significant differences among the materials (p <0.05). The Biodentine specimens had the highest push-out bond strength values (p < 0.05). MTA HP had significantly higher bond strength than White MTA (p < 0.05). MTA HP showed better push-out bond strength than its predecessor, White MTA; however, Biodentine had higher dislodgment resistance than both MTA formulations.

Endodontic treatment of a mandibular hypertaurodontic second molar / Tratamento endodôntico de segundo molar inferior com hipertaurodontia

Taurodontism is the consequence of a developmental disorder in which the invagination of Hertwig's epithelial root sheath doesn't occur at a proper level. As a result, the pulp body and the chamber of a multi-root tooth, usually permanent molar teeth, are enlarged by the apical displacement of the pulp floor. Despite its clinically normal appearance, the morphological variation of this tooth can be diagnosed by a routine radiographic exam that shows enlarged apico-occlusal pulp chamber and short roots. Due to these anatomical variations, endodontic treatment of a taurodontic element is a clinical challenge given the complexity of localization and instrumentation of the root canal system. According to the degree of displacement of the pulp floor, taurodontism can be classified as: hypotaurodontism, mesotaurodontism and hypertaurodontism. This study objective is to report a clinical case of a patient who was submitted to endodontic treatment of the second inferior molar affected by hypertaurodontism.

A taurodontia é consequência de um distúrbio de desenvolvimento em que a bainha epitelial de Hertwig não invagina corretamente em um nível normal, repercutindo em um aumento do corpo e da câmara pulpar de um dente multiradicular, predominantemente molares permanentes, pelo deslocamento do assoalho pulpar no sentido apical. Apesar de clinicamente aparentar-se como um dente normal, esta variação morfológica pode ser diagnosticada por exame radiográfico de rotina evidenciando câmara pulpar aumentadas em tamanho no sentido ápico-oclusal e raízes curtas. Devido a estas alterações anatômicas, o tratamento endodôntico de um elemento com taurodontia se torna um desafio clínico, já que é necessário um cuidado especial na localização e manejo do sistema de canais radiculares. De acordo com o grau de deslocamento apical do assoalho pulpar, a taurodontia pode ser classificada em: hipotaurodontia, mesotaurodontia e hipertaurodontia. O objetivo deste trabalho é relatar o caso clínico de um paciente que necessitou de tratamento endodôntico em um segundo molar inferior com hipertaurodontia.

Superfícies biomiméticas: novo paradigma da osseointegração / Biomimetic surfaces: new paradigm of osseointegration

O sucesso dos implantes está, frequentemente, associado ao processo de osseointegração. Isso leva a uma busca por tratamentos de superfície para que o titânio se torne cada vez mais bioativo e induza a neoformação óssea. O conceito da superfície biomimética surge com o intuito de gerar uma superfície que module positivamente a osseointegração, de modo que o implante apresente capacidade de osteoindução por meio do reconhecimento biomolecular da superfície. A hidroxiapatita e os fosfatos de cálcio foram os primeiro agentes propostos para o biomimetismo da superfície com o tecido ósseo; no entanto, hoje é proposta a utilização de proteínas da matriz extracelular óssea e fatores de crescimento para mimetizar a fisiologia do tecido e aumentar ainda mais a previsibilidade dos implantes. Quando os resultados das pesquisas puderem ser traduzidos em projetos industriais, novas superfícies podem surgir no mercado, garantindo maior segurança para a instalação de implantes em sítios ósseos desfavoráveis e o carregamento oclusal precoce.

Dental implants success is often associated with the osseointegration process. To induce the bone formation, there is a search for surface treatments to create a more bioactive titanium. The concept of biomimetic surface arises in order to generate a surface that positively modulates the implant osseointegration, presenting osteoinductive capacity through the biomolecular recognition of the surface. Hydroxyapatite and calcium phosphates were the first agents proposed for surface coating to mimic the bone tissue; however. the use of bone extracellular matrix proteins and growth factors have been proposed to mimic the physiology of the tissue and further increase its predictability. When the research results become translated into industrial projects, new surfaces may emerge in the market providing greater security for implants installation in unfavorable bone sites and early occlusal loading.

Influence of immersion time of denture cleansers on the surface roughness of resilient denture liners / Influência do tempo de imersão de limpadores químicos sobre a rugosidade de superfície de reembasadores resilientes para próteses removíveis

PURPOSE: The objective of this study was to evaluate the effect of different immersion times in denture cleansers on surface roughness (SR) of two resilient denture liners (RDL) after the cleanliness of Candida albicans biofilm. METHODS: Poly(methyl methacrylate) (PMMA) resin discs (10x1.5 mm) were relined with a 1.5 mm layer of RDL (PMMA or silicone-based). The initial SR of each specimen was measured and C. albicans biofilm was developed for 48 h. Subsequently, the discs were randomly assigned for one of four cleansing treatments (n=8): two alkaline peroxide (soaking for 3 or 15 min), 0.5 percent sodium hypochlorite (10 min) or distilled water as control (15 min). After the treatments, the SR was measured again. Data were analyzed by ANOVA and the Tukey post-hoc test (α=0.05) RESULTS: No differences were found between the cleansing treatments evaluated (P>0.05). The PMMA-based liner exhibited higher SR than silicon-based (P<0.001); however, both liners showed higher SR after the reatments compared with the baseline values (P<0.001). CONCLUSION: Within limitations of this study, it can be concluded that the surface roughness of RDL increased after the immersion in denture cleansers, independently of the time of immersion.

OBJETIVO: O objetivo deste estudo foi avaliar o efeito de diferentes tempos de imersão em limpadores químicos sobre a rugosidade de superfície ( RS)de reembasadores resilientes após a simulação da limpeza de biofilmes de Candida albicans. METODOLOGIA: Discos (10x1,5 mm) de poli(metilmetacrilato) (PMMA) foram cobertos com uma camada de 1,5 mm de reembasador resiliente (a base de PMMA ou silicone). A RS inicial de cada espécime foi mensurada e biofilmes de C. albicans desenvolvidos por 48 h. Em seguida, os espécimes foram submetidos aleatoriamente a um dos tratamentos (n=8): duas soluções alcalinas a base de peróxido (imersão por 3 ou 15 min), hipoclorito de sódio a 0.5 por cento (10 min) ou água destilada como grupo controle (15 min). Após o tratamento, a RS foi mensurada novamente. Os resultados foram analisados por ANOVA e teste Tukey (α=0,05). RESULTADOS: Não houve diferença estatística entre os tratamentos (P>0,05). O reembasador a base de PMMA apresentou maior RS que os de silicone (P<0,001); entretanto, ambos apresentaram um aumento da RS após os tratamentos (P<0,001). CONCLUSÃO: Dentro das limitações deste estudo, conclui-se que a RS dos reembasadores resilientes aumenta após a imersão em limpadores químicos, independentemente do tempo de imersão.

Effect of bovine hydroxyapatite on early stages of bone formation / Efeito da hidroxiapatita bovina no período inicial de formação óssea

PURPOSE: This study aimed to characterize the effect of bovine hydroxyapatite particles (HA) on the early stages of bone repairing in a rat femur defect model. METHODS: A non-critical 2 mm diameter bone defect was made in both femurs of 25 male albino Wistar rats. The left femurs defects were filled with HA and the right femurs defects were just let to fill with blood. Five animals were sacrificed at the 1st, 3rd, 5th, 7th or 14th post-surgery day and bone tissue sections were stained with hematoxylin and eosin for comparison of inflammatory response by light microscopy. Histomorphometrical analysis of the newly formed bone was evaluated at the three last periods, using independent t-student test to compare both groups at each period (a=0.05). RESULTS: Histological analyses showed same standard of bone repair on first and third day; however, from the fifth post-surgery day there was a higher deposit of collagen fibers surrounding the hydroxyapatite particles and a greater thickness of the opposite side periosteum. There was no significant histomorphometrical difference between groups at all periods. CONCLUSION: It can be concluded that hydroxyapatite does not accelerate the early-stage of bone repairing, despite of induction of a higher deposit of collagen fibers.

OBJETIVO: O objetivo deste estudo foi caracterizar o efeito das partículas de hidroxiapatita bovina (HA) nos estágios iniciais da reparação óssea em modelo de defeito ósseo em fêmur de ratos. METDOLOGIA: Defeito ósseo não crítico de 2 mm de diâmetro foi feito em cada fêmur de 25 ratos Wistar albinos. O defeito do fêmur esquerdo foi preenchido com HA enquanto a cavidade direita foi preenchida apenas com sangue. Cinco animais foram sacrificados no 1º, 3º, 5º, 7º e 14º dia pós-cirúrgico. Os cortes histológicos do tecido ósseo foram corados com hematoxicilina e eosina para comparação da resposta inflamatória por microscopia óptica. Análise histomorfométrica do tecido ósseo neoformado foi avaliado nos três últimos períodos utilizando o teste t de Student para comparação de ambos os grupos em cada período de avaliação (a=0,05). RESULTADOS: A análise histológica mostrou o mesmo padrão de reparação óssea no 1º e 3º dia; entretanto, no 5º dia pós-cirúrgico houve um maior depósito de fibras de colágeno ao redor dos cristais de hidroxiapatita e uma maior espessura do perióstio oposto. Não houve diferença histomorfométrica significativa entre os grupos em todos os períodos avaliados. CONCLUSÃO: Pode ser concluído que a hidroxiapatita não acelera os estágios inicias da reparação óssea, apesar de induzir a um maior depósito de fibras de colágeno.

Rapid denture fabrication for institutionalized patients / Confecção rápida de prótese total para pacientes institucionalizados

PURPOSE: Edentulism is a common condition among the elderly population. However, it is difficult for elderly subjects who are institutionalized, hospitalized, or bedridden to visit dental offices for the repair or replacement of broken dentures. This paper describes a fast technique with minimum clinical sessions to fabricate a new maxillary denture. CASE DESCRIPTION: An institutionalized 78-year-old man with an extremely damage broken maxillary denture complained about repairing his denture. With the impossibility of repairing, the technique described was proposed so as to offer a treatment that would maximize the comfort of the patient. The maxilla-mandibular relationship was done at the first clinical session, after fabricating the maxillary resin baseplate in mouth, by fixing the old complete mandibular denture with the maxillary wax plane. At the second clinical session, the esthetics and function of artificial teeth was checked and final impression was made to the denture installation at next session. CONCLUSION: The reduced number of clinical sessions is a convenient option for clinicians to provide a more comfortable treatment for institutionalized or bedridden patients. This technique is also particularly useful when a replacement denture is urgently required, allowing its installation within few hours.

OBJETIVO: O edentulismo é uma condição comum dentre a população idosa. Entretanto, quando estes indivíduos encontram-se institucionalizados, hospitalizados ou acamados, consultar um cirurgião-dentista para reparo ou substituição de próteses totais pode ser uma situação difícil. Neste caso, é relatada uma técnica mais rápida para confecção de uma prótese total superior em um número mínimo de sessões clínicas. DESCRIÇÃO DO CASO: Indivíduo institucionalizado de 78 anos de idade, apresentando uma prótese extremamente danificada após deixá-la cair sobre o chão, queixava de necessidade de reparo na mesma. Na impossibilidade de reparo, foi proposta esta técnica descrita para oferecer um tratamento com maior conforto para o paciente. O relacionamento maxilo-mandibular foi feito na primeira sessão clínica, após confeccionar a base de prova diretamente em boca, fixando a própria prótese inferior do paciente com o plano de cera. Na segunda sessão clínica, a prova estética e funcional é feita e a moldagem final realizada para instalação da prótese na sessão seguinte. CONCLUSÃO: O número reduzido de sessões clínicas é uma opção conveniente para os clínicos e gera um tratamento mais confortável para indivíduos institucionalizados ou acamados. Esta técnica também pode ser útil para substituição de prótese total em caráter de urgência, onde a prótese pode ser instalada no mesmo dia ou no dia seguinte.

Relationship among malocclusion, number of occlusal pairs and mastication

This study evaluated the relationship among malocclusion, number of occlusal pairs, masticatory performance, masticatory time and masticatory ability in completely dentate subjects. Eighty healthy subjects (mean age = 19.40 ± 4.14 years) were grouped according to malocclusion diagnosis (n = 16): Class I, Class Class II-2, Class III and Normocclusion (control). Number of occlusal pairs was determined clinically. Masticatory performance was evaluated by the sieving method, and the time used for the comminute test food was registered as the masticatory time. Masticatory ability was measured by a dichotomic self-perception questionnaire. Statistical analysis was done by one-way ANOVA, ANOVA on ranks, Chi-Square and Spearman tests. Class II-1 and III malocclusion groups presented a smaller number of occlusal pairs than Normocclusion (p < 0.0001), Class I (p < 0.001) and II-2 (p < 0.0001) malocclusion groups. Class I, and III malocclusion groups showed lower masticatory performance values compared to Normocclusion (p < 0.05) and Class II-2 (p < 0.05) malocclusion groups. There were no differences in masticatory time (p = 0.156) and ability (χ2 = 3.58/p= 0.465) among groups. Occlusal pairs were associated with malocclusion (rho = 0.444/p < 0.0001) and masticatory performance (rho = 0.393/p < 0.0001), but malocclusion was not correlated with masticatory performance (rho = 0.116/p= 0.306). In conclusion, masticatory performance and ability were not related to malocclusion, and subjects with Class I, II-1 and III malocclusions presented lower masticatory performance because of their smaller number of occlusal pairs.

Long-term efficacy of denture cleansers in preventing Candida spp. biofilm recolonization on liner surface

This study evaluated the long-term efficacy of denture cleansers against Candida spp. biofilm recolonization on liner surface. Specimens were fabricated of a poly(methyl methacrylate)-based denture liner and had their surface roughness evaluated at baseline and after cleansing treatments. C. albicans or C. glabrata biofilms were formed on liner surface for 48 h, and then the specimens were randomly assigned to one of cleaning treatments: two alkaline peroxides (soaking for 3 or 15 min), 0.5 percent sodium hypochlorite (10 min) or distilled water (control; 15 min). After the treatments, the specimens were sonicated to disrupt the biofilm, and residual cells were counted (cell/mL). Long-term effectiveness of the cleaning processes was determined by submitting a set of cleaned specimens to biofilm growth conditions for 48 h followed by estimation of cell counts. The topography of specimens after cleaning treatments was analyzed by SEM. Data were analyzed by ANOVA and Tukey's test (α; = 0.05). Results of cell count estimation showed significant differences in cleanliness among the treatments (p < 0.001), and it could be observed by SEM. However, no significant difference (p > 0.05) was observed among the Candida species regarding the recolonization condition. Alkaline denture cleansers showed similar cleaning performance and both differed from the control (p < 0.001). Sodium hypochlorite was the only treatment that removed biofilm efficiently, since no viable cells were found after its use. In conclusion, alkaline peroxide denture cleansers were not effective in removing Candida spp. biofilm from denture liner surfaces and preventing biofilm recolonization.