Effects of the Finishing Protocols and Oral Hygiene Procedures in the Microhardness and Surface Roughness of CAD/CAM Ceramics

ABSTRACT: The objective of this in vitro study was to evaluate the effects of finishing protocols and oral hygiene procedures on the surface and mechanical properties of CAD/CAM ceramics. Specimens (n = 96, (15x10x2mm) of the leucite glass-ceramic (LGC) and feldspathic ceramic (FP) received mechanical polishing or glazing. Surface roughness (Ra) and microhardness (VHN) were obtained with a profilometer and a hardness tester, respectively, before and after each oral hygiene procedure (TB: toothbrushing; PB: prophylaxis with paste and rubber cup; and BJ: prophylaxis with bicarbonate jet). ANOVA, paired t and Tukey's tests were applied (a=0.05). For both materials, only BJ affected Ra's values when mechanical polishing was performed. Moreover, no significant variations in VHN were observed only for LGC glazed with TB. Significant Ra and VHN changes in both materials were observed with BJ. Besides, BJ exhibited similar effects to TB on VHN, regardless of the material and finishing protocol used. Changes in mechanical and surface properties varied with the finishing protocol and the oral hygiene method. In general, prophylaxis with bicarbonate jet was the most harmful method for both materials and the type of finishing protocol did not have a protective effect against changes produced by oral hygiene methods.

RESUMEN: El objetivo de este estudio in vitro fue evaluar los efectos de los protocolos de acabado y los procedimientos de higiene oral sobre la superficie y las propiedades mecánicas de las cerámicas CAD/CAM. Los especímenes (n = 96, (15x10x2mm) de vitrocerámica de leucita (LGC) y cerámica feldespática (FP) recibieron pulido mecánico o glaseado. La rugosidad de la superficie (Ra) y la microdureza (VHN) se obtuvieron con un perfilómetro y un probador de dureza, respectivamente, antes y después de cada procedimiento de higiene oral (TB: cepillado dental; PB: profilaxis con pasta y vaso de hule; y BJ: profilaxis con chorro de bicarbonato). Se aplicaron ANOVA, t pareada y prueba de Tukey (a=0.05). Para ambos materiales, solo BJ afectó los valores de Ra cuando se realizó el pulido mecánico. Además, no se observaron variaciones significativas en VHN solo para LGC vidriado con TB. Se observaron cambios significativos de Ra y VHN en ambos materiales con BJ. Además, BJ exhibió efectos similares a TB en VHN, independientemente del material y protocolo de acabado utilizado Los cambios en las propiedades mecánicas y superficiales variaron con el protocolo de acabado y el método de higiene oral. En general, la profilaxis con chorro de bicarbonato fue el método más perjudicial, tanto los materiales como el tipo de protocolo de acabado no tuvieron un efecto protector frente a los cambios producidos por los métodos de higiene oral.

Reabilitação oral de paciente com redução de dimensão vertical de oclusão utilizando prótese parcial removível overlay: relato de caso / Oral rehabilitation of patient with reduced vertical dimension of occlusion using overlay removable partial denture: case report

A reabilitação oclusal de pacientes parcialmente desdentados com redução da dimensão vertical de oclusão (DVO) representa um grande desafio para o cirurgião-dentista. Normalmente envolve procedimentos complexos, demorados e de elevado custo. A prótese parcial removível (PPR) do tipo overlay representa uma alternativa reabilitadora que pode ser utilizada para esta finalidade. Por meio do relato de um caso clínico, este trabalho teve por objetivo descrever a técnica de utilização da PPR overlay, bem como discutir a viabilidade clínica e efetividade desta modalidade de tratamento. No caso em questão, diagnosticada a redução da DVO, inicialmente a reabilitação oral foi feita de forma provisória, utilizando PPR overlay provisória no arco superior e PPR provisória convencional no arco inferior. O restabelecimento das posições mandibulares possibilitou a reconstrução dos dentes anteriores desgastados com resina composta e a confecção de PPR overlay com recobrimento metálico como tratamento "definitivo". As PPRs de recobrimento (overlays) representam uma excelente e eficiente alternativa no restabelecimento das relações maxilomandibulares. São procedimentos menos onerosos que os procedimentos fixos convencionais, normalmente utilizados na reabilitação de pacientes com diminuição da DVO, mais conservadores e bem indicados para pacientes que tiveram desgastes em função de hábitos parafuncionais.

The occlusal rehabilitation of partially edentulous patients with reduced vertical dimension of occlusion (VDO) represents a great challenge for the dentist. Normally, involving complex, time-consuming and expensive procedures. The removable partial denture (RPD) overlay type represents a rehabilitative alternative that can be used for this purpose. Through the report of a case, this study aimed to describe the use of the RPD overlay technique as well as discuss the clinical feasibility and effectiveness of this treatment modality. In this case, diagnosed the VDO reduction, initially, the oral rehabilitation was made provisionally, using provisory overlay RPD on the upper arch and conventional provisory RPD in the lower arch. The restoration of mandibular positions made possible the reconstruction of the worn anterior teeth with composite resin and the production of the overlay RPD with metallic covering as the "definitive" treatment. The covering RPDs (overlays) are an excellent and efficient alternative on the restoration of the maxillomandibular relations. They are less costly procedures than conventional fixed procedures, normally used in the rehabilitation of patients with decreased VDO, more conservative and well suited for patients who had wear due parafunctions habits.

Effects of bleaching agents and adhesive systems in dental pulp: a literature review

The dental pulp may be exposed to several irritants that are potentially noxious to the health and functions of this tissue. Each type of irritant or injury has different effects on the pulp, which are generally characterized by acute inflammation, chronic inflammation or necrosis. Common examples of irritants are dental caries, cavity preparation procedures, traumatic injuries, and chemical substances like bleaching agents and adhesive systems. The present study aimed to review the current knowledge about the effect of bleaching agents and adhesive systems in the human dental pulp. The review covered literature from 2004 to 2009, and only relevant manuscripts were included. Hand search of the references completed the review. Based on literature review, it may be concluded that all dental procedures associated with bleaching agents or adhesive systems involve risks to cause pulp damage. However, these risks can be minimized if the causal factors were known and avoided.

Permeability, roughness and topography of enamel after bleaching: tracking channels of penetration with silver nitrate

Aim: This study evaluated the surface roughness, topography and permeability of bovine enamel by profilometry and scanning electron microscopy (SEM) with and without silver nitrate solution, after exposure to different bleaching agents. Methods: Fifty-two enamel samples were randomly divided into four groups (n=13): CP16% –16% carbamide peroxide - Whiteness Perfect; HP6% - 6% hydrogen peroxide - White Class; HP35% - 35% hydrogen peroxide Whiteness HP Maxx; and Control - not bleached and kept in artificial saliva. For roughness analysis, average surface roughness (Ra) and flatness coefficient (Rku) parameters were used. The topography and permeability were examined by SEM. For permeability evaluation, the samples were immersed in a 50% silver nitrate solution and analyzed using a backscattered electron and secondary electron mode. Results: For the roughness (Ra) evaluation, Kruskal-Wallis and Wilcoxon Signed Ranks Test were used, showing an increase on the surface roughness in all bleached groups. The Rku parameter suggested changes on enamel integrity. The SEM micrographs indicated changes on enamel topography and different levels of silver nitrate penetration in the samples of the bleached groups. In the overall analysis, the bleaching agents promoted surface changes and higher silver nitrate penetration when compared to the control group. Conclusions: It may be concluded that different bleaching agents might alter the topography and roughness of enamel surface. Moreover, the higher infiltration of silver nitrate suggests an easier penetration path for the oxygen molecules into the dentin substrate.

Para reconstruções de dentes tratados endodonticamente, utilizo pino intrarradicular de fibra de vidro ou metálico?

Mostra o ponto de vista de dois profissionais da área de Odontologia, sobre a utilização de pino intrarradicular de fibra de vidro ou metálico para reconstruções de dentes tratados endodonticamente. Para os dois profissionais não existe o pior, ou o melhor método, pois deve-se analisar cuidadosamente a técnica que melhor se adequa à situação do paciente.

Influence of powder/liquid ratio on the radiodensity and diametral tensile strength of glass ionomer cements

Clinicians tend to make reductions in glass ionomer power/liquid (P/L) ratios since some materials are difficult to mix and flow into small cavities, grooves or pits. In general, changing the P/L ratio decreases the physical and mechanical properties of conventional glass ionomer cements (GICs) and resin modified glass ionomer cements (RMGICs), but alterations seem to depend on their composition. OBJECTIVE: To determine the influence of P/L ratio on the radiodensity and diametral tensile strength (DTS) of glass ionomer cements. MATERIAL AND METHODS: There were 2 factors under study: P/L ratio (manufacturer's recommended P/L ratio and a 50 percent reduced P/L ratio), and materials (Vitro Molar, Vitro Fil, Vitro Cem conventional GICs and Vitro Fil LC, Ortho Glass LC RMGICs. Five 1-mm-thick samples of each material-P/L ratio were produced for radiodensity evaluation. Samples were x-ray exposed onto Digora phosphor plate and radiodensity was obtained using the software Digora for Windows 2.5 Rev 0. For DTS, five (4.0x8.0 mm) cylinder samples of each material were tested (0.5 mm/min). Data were subjected to one- and two-way ANOVA (5x2) followed by Tukey's HSD test, or Kruskal-Wallis and Dunn's method. For paired comparisons, t-test or Mann-Whitney test were used (α=0.05). RESULTS: There was a significant interaction (P=0.001) for the studied factors (materials vs. P/L ratio). Reduced P/L ratio resulted in significantly lower DTS for the RMGICs, but radiodensity was affected for all materials (P<0.05). CONCLUSIONS: Reduced P/L ratio affected properties of the tested glass ionomer cements. RMGICs were more susceptible to lower values of DTS, but radiodensity decreased for all materials following P/L ratio reduction.

Avaliação clínica de clareamento caseiro com gel de peróxido de carbamida industrializado e manipulado em farmácia / Tooth bleaching clinical evaluation with industrialized and drugstore manipulated carbamide peroxide gel

Este trabalho objetivou avaliar clinicamente o uso de clareamento dental caseiro com peróxido de carbamida 10% industrializado e manipulado. Quarenta pacientes foram selecionados com indicação de receber clareamento caseiro e divididos em dois grupos: G1- peróxido de carbamida 10% com Carbopol manipulado em drogaria e G2- peróxido de carbamida 10% com Carbopol industrializado (Whiteness-FGM-Joinvile-SC-Brasil). A análise se baseou nos parâmetros: variação do grau de escurecimento dental por meio de escala de cores (Vita Classic); satisfação pessoal do paciente; sensibilidade pós-operatória, irritação gengival e vitalidade pulpar. Os dados obtidos foram analisados qualitativamente mediante distribuição por freqüência. Os resultados foram: alteração de cor após uma semana de uso do gel clareador: G1- redução de um nível de saturação e G2- redução de dois níveis de saturação e após duas semanas de uso do gel clareador; satisfação do paciente: G1- 68,0% e G2- 82,7%; sensibilidade pós-operatória: G1- 40,0% e G2- 10,0%; irritação gengival: G1-10,0% e G2- 5,0%. Não houve alteração na vitalidade pulpar com o uso dos dois produtos analisados. Pôde-se concluir que os dois materiais apresentaram desempenhos diferenciados, sendo o produto industrializado o mais eficiente para o uso clínico.

The aim of this study was to realize the clinical follow-up of vital tooth bleaching realized with manipulated and industrialized 10% carbamide peroxide gel. Forty patients were selected with indication to receive tooth bleaching and divided in two groups: G1-Twenty patients received drugstore manipulated 10% carbamide peroxide with carbopol, and G2- twenty patients received industrialized 10% carbamide peroxide (Whiteness-FGM-Joinvile-SC-Brasil). The analysis if based on the parameters: degree of tooth discoloration before and after treatment, using Vita shade guide; personal satisfaction of patients; post-operative tooth sensibility; gingival irritation and pulp vitality. The data were analyzed qualitatively by frequency distribution. The results showed: color alteration after one week of use of the gel: G1- reduction of a level of saturation and G2- reduction of two levels of saturation; e after two weeks of use of the gel: satisfaction of the patient: G1- 68.0% and G2- 82,7%; post-operative tooth sensibility: G1- 40.0% and G2- 10,0%; gingival irritation: G1-10,0% and G2- 5,0%. It did not have alteration in the pulp vitality with the use of the two analyzed products. It can conclude that the manipulated and industrialized 10% carbamide peroxide showed different results, been industrialized gel more efficient to clinical usage.

Influence of time elapsed between application and adhesive polymerization on the bond strength to dentin

The aim of this study was to evaluate the influence of time elapsed between dentin adhesive application and its polymerization on the bond strength to dentin. Superficial bovine dentin received the following treatments: Single Bond (3M/ESPE Dental Products Division, St.Paul, MN, USA), Excite (Ivoclar/Vivadent, Schaan, Liechtenstein), Prime&Bond 2.1 (Dentsply/Caulk, Milford, DE, USA) and One-Up Bond F (Tokuyama Corp.,Tokyo, Japan) being polymerized immediately after its application, 10 and 20 seconds after application. After, indirect composite restoration was fixed with resinous cement RelyX Arc (3M/ESPE). The restoration/tooth interface was observed on Scanning Electron Microscopy (SEM). Bond strength was accessed through a shear bond test on a testing machine at 0.5 mm/min. Data were compared by ANOVA followed by Tukey test (á=0.05). The failure modes was observed by means of stereo-microscope (40X magnification), being classified as adhesive, dentin cohesive, resin cohesive and mixed failure. There was no significant difference on the bond strength between the 10s and 20s groups for the majority of the materials. However, both the failure modes and the SEM showed better interaction between dentin and adhesive systems after elapsed 20s its application. It was concluded that longer periods of adhesive system application resulted on better interaction between dentin and adhesive systems evaluated.

Procedimentos adesivos empregados na transformação de dentes conóides e fechamento de diastemas / Direct adhesive procedures employed on peg-shaped teeth transformation and closing diastemata

A demanda estética na Odontologia é gerada pela preocupação da sociedade moderna com a beleza. Os autores apresentam caso clínico que envolve a presença de incisivos laterais superiores conóides, diastemas entre elementos dentais e inversão do sorriso devido ao comprimento inferior dos incisivos centrais em relação aos lateriais. Foi proposta a transformação dental empregando procedimentos adesivos diretos com a associação de hibridização da estrutura dental com resina composta híbrida e micropartícula. Após o planejamento, feito por meio de enceramento em modelo de estudo, foi realizado a transformação dos incisivos laterais conóides, acréscimo na porção incisal dos incisivos centrais e fechamento de diastemas proporcionando harmonia e estética e oclusal do sistema estomatognático

Clareamento caseiro associado a procedimentos restauradores diretos na reabilitação estética do sorriso / Nightguard vital bleaching associated with direct restoration on esthetic rehabilitation of smile

Os autores apresentam caso clínico que envolve escurecimento dental com presença de incisivos conóides e restaurações anteriores insatisfatórias. O objetivo deste trabalho é demonstrar, passo a passo, a técnica de clareamento dental caseiro com peróxido de carbamida 10 por cento (Whiteness FGM) associado ao emprego de resina composta na tranformação dental. Serão abordados a interferência e os cuidados a serem observados nas restaurações adesivas de dentes submetidos ao clareamento dental, objetivando a obtenção de resultado estético e funcional com longevidade. A satisfação do paciente, com reflexo direto no sucesso profissional, demonstra que a realização de procedimentos estéticos pouco invasivos é importante aliada do Clínico na prática da Odontologia Estética

Aplicaçäo tópica de flúor - efeito sobre a porcelana dental / Topic fluoride aplication - effect on dental porcelain

Este trabalho se propôs a avaliar o efeito do flúor neutro e flúor fosfato acidulado sobre a porcelana dental através da análise da rugosidade superficial e variaçäo da massa. 70 amostras foram confeccionadas com as porcelanas Vita VMK-68 e Ivoclar IPS Classic. Essas amostras foram pesadas em balança analítica e analisadas em rugosímetro. Posteriormente foram imersas em grupos de 5 no flúor neutro e acidulado nos períodos de 4 minutos, 60 minutos e 24 horas. Em seguida foram lavadas, secas em estufa e reavaliadas. Os resultados demonstraram que o flúor fosfato acidulado produziu efeito estatisticamente significante na reduçäo da massa e aumento da rugosidade em ambas as porcelanas; o fator tempo produziu efeito cumulativo para o flúor acidulado. O flúor neutro näo produziu efeito sobre a porcelana dental sendo portanto uma alternativa viável na aplicaçäo tópica de flúor como método preventivo da cárie dental em pacientes portadores de prótese metalocerâmica

Removível com grampos estéticos: nova soluçäo estética para próteses parciais removíveis (Próteses "Metal-Free" -Tipo Dental D©) / Partial dentures with sthetical clamps: a new solution fos sthetics in partial denture

Relato de um caso clínico no qual paciente de 65 anos, possuindo prótese total na arcada superior e prótese parcial removível na arcada inferior (Classe I), necessitando confecçäo de nova prótese parcial removível