Effect of 0.2% peracetic acid disinfection on the horizontal dimension of implant framework indexed with two autopolymerized acrylic resins.

BACKGROUND: To minimize misfit between prosthesis and implant, the welding of the implant fixed partial denture (IFPD) framework is recommended and autopolymerized acrylic resin (AR) is the material of choice for the indexing process. As for any prosthetic device that comes into contact with saliva and blood in the oral cavity, IFPD indexed with AR must be disinfected before sending to the laboratory. However, disinfection procedures are often neglected for fear of shrinkage or distortion caused by a dimensional change of the acrylic resin. Peracetic acid is a high-level disinfectant agent at low concentrations and immersion time, with no reported toxic residues, and it is not inactivated in the presence of organic matter when compared to other disinfectants. This study aimed to evaluate the influence of 0.2% peracetic acid disinfectant solution after different storage media and times on the horizontal dimension of IFPD frameworks indexed with AR. MATERIAL AND METHODS: IFPD frameworks were indexed with two AR: group 1 Duralay and group 2 Pattern Resin LS. Each group was further divided into five subgroups according to disinfection procedure and storage medium: no disinfection and dry storage, no disinfection and water storage, 0.2% peracetic acid disinfection and water storage, 0.2% peracetic acid disinfection and peracetic acid storage, and 0.2% peracetic acid disinfection and dry storage. The horizontal dimension of the specimens and an average was established for analysis. Measurements were performed at four different storage times (hours): T0, T24, T48, T168. RESULTS: No statistical differences were found when T0 was compared to T168 for Pattern resin groups submitted to disinfection and storage in water (group 2b, p = 1.000) or peracetic acid solution (group 2c, p = 0.352). For Duralay groups, the use of peracetic acid solution did not affect the horizontal dimension of the specimens when T0 was compared to T168 only with water as a storage medium (group 1b, p = 1.000). Additionally, T0 did not differ from T24 for groups 1c (p = 0.553), 2b (p = 1.000), 2d (p = 0.234), and 2e (p = 1.000) and from T48 for groups 1d (p = 0.118) and 2b (p = 1.000). CONCLUSION: Within the studied conditions, the use of 0.2% peracetic acid can be safely used as a disinfectant solution regarding dimensional stability of AR-indexed IFPD until 7 days of storage. Horizontal discrepancies are dependent on acrylic resin type, time, and medium of storage.

Influence of polishing systems on roughness and color change of two dental ceramics.

PURPOSE: To evaluate the polishing effect on roughness and color change of pressed and layering ceramics after immersion in coffee solution. MATERIALS AND METHODS: 88 ceramic discs (1.0 mm × 10.0 mm) were manufactured - 44 nano-fluorapatite layering ceramics (IPS e.max Ceram. Group C) and 44 pressed lithium disilicate ceramic discs (IPS e. max Press - Group P). Each group was divided into 4 subgroups according to surface treatments: (G) Glaze, (S) Shofu polishing system (Shofu Inc.), (E) Edenta AG polishing System, (KG) 30-µm diamond granulation tip. Surface roughness (Ra) and color change (ΔE) measurings after the surface treatments were performed, before and 12 days after the immersion in coffee solution. A samples' qualitative analysis was conducted with a scanning electron microscopy (SEM). Data were statistically-treated with one-way-ANOVA and Duncan's tests, apart from paired t-test and Pearson's correlation test (α=5%). RESULTS: The decrescent order, both for surface roughness (Ra) and ΔE for both ceramics were: KG > E > S > G (P<.05). With exception for PG and CG subgroups, which did not present statistical difference between them, all other pressed ceramics subgroups presented smaller Ra values and greater ΔE values than the layering ceramics subgroups (P<.05). CONCLUSION: Although mechanical polishing systems presented intermediate Ra values, their colors were considered clinically acceptable. There is a strong correlation between the surface roughness and the color change of tested ceramics.

Role of additional retention on marginal adaptation and sealing of large resin composite Class II restorations.

PURPOSE: To compare marginal leakage and gap formation in large resin composite Class II cavities with their gingival margins in cementum, using three different additional retentions in the proximal box. METHODS: Standardized large Class II MOD cavities with gingival margins in cementum were prepared in 40 recently extracted molars and divided into four groups according to their retention in the proximal box: (G1) no retention; (G2) vertical grooves in the buccal and lingual walls; (G3) "pot holes" in the gingival wall and (G4) horizontal grooves in the gingival wall. All groups were restored with the incremental technique using the same resin composite (QuiXfil, Dentsply) and a bonding agent (Prime Bond NT, Dentsply). After polishing, all of the restored teeth were immersed in dye solution and submitted to simultaneous cyclic loading. Impressions of the gingival margins were made before and after loading, and epoxy resin replicas were evaluated for gap formation using a scanning electron microscope. The microleakage and gap extension data were evaluated by ANOVA and Tukey's test (p < 0.05). Gap extension before and after mechanical loading was compared by Student's t-test. A correlation analysis was made between the gap extension and microleakage (Pearson's correlation test). RESULTS: All groups with additional retention (G2 = 0.565, G3 = 0.346 and G4 = 0.078) showed fewer gap formations than the control group (G1 = 2.076). Similar results were found for microleakage tests. All groups presented an increase in gap extension after loading, with the exception of the group with gingival retention grooves (G4). G4 showed the best results in relation to both parameters. There was a low correlation between gap extension and microleakage.

Use of base metal casting alloys for implant framework: marginal accuracy analysis.

The original protocol for implant prosthesis recommends the use of a gold framework for acrylic and ceramic prosthesis. However, due to its high cost, the use of alternative alloys is desired. This study compares the marginal accuracy of pre-made cylinders versus plastic cylinders cast with two different base metal casting alloys. Five samples each of (1) plastic cylinder cast in cobalt-chromium alloy, (2) plastic cylinder cast in nickel-chromium alloy, and (3) silver-palladium pre-made cylinder (control) were examined for marginal accuracy according to: (A) vertical gap; (B) horizontal gap and (C) horizontal gap depth at the abutment/cylinder interface. Data were submitted to statistical analysis (ANOVA and Student-Newman Keuls, p<0.05). Mean values for vertical, horizontal and gap depth were 4.13µm, 14.5µm and 6.93µm for pre-made cylinder, 23.18µm, 33.2µm and 88µm for Ni-Cr cast cylinder and 25.6µm, 51.8µm and 114.54µm for Co-Cr cast cylinder. No statistically significant differences were found between cast groups (1 and 2), but significant better fit was obtained with pre-made metal cylinders when compared to cast cylinders with Ni-Cr and Co-Cr alloys, for all analyses.

Use of base metal casting alloys for implant framework: marginal accuracy analysis

O protocolo para prótese sobre implantes recomenda o uso de uma infra-estrutura em ouro para próteses metalo-plásticas e metalo-cerâmicas. No entanto, devido ao seu alto custo, o uso de ligas alternativas é desejado. OBJETIVO: Este estudo compara a adaptação marginal de cilindros protéticos pré-fabricados e cilindros protéticos plásticos fundidos com dois tipos de ligas metálicas básicas. MATERIAL E MÉTODOS: 05 amostras de (1) cilindros plásticos fundidos em liga de cobalto cromo; (2) cilindros plásticos fundidos em liga de níquel cromo e (3) cilindros pré-fabricados com cinta metálica em paládio, foram examinados na interface intermediário/cilindro protético na análise de desajuste marginal, considerando-se (A) desajuste vertical, (B) desajuste horizontal e (C) profundidade de fenda. RESULTADOS: os valores médios para o desajuste vertical, horizontal e profundidade foram, respectivamente, 4,13µm, 14,5µm e 6,93µm para o cilindro pré-fabricado em paládio, 23,18µm, 33,2µm e 88µm para os cilindros plásticos fundidos em Níquel cromo e 25,6µm, 51,8µm e 114,54 µm para os cilindros fundidos em cobalto-cromo. CONCLUSAO: não foram encontradas diferenças estatísticas entre os grupos fundidos (grupo 1 e 2), mas uma adaptação marginal significantemente superior foi observada com os cilindros pré-fabricados quando comparado aos cilindros plásticos fundidos com níquel-cromo e cobalto-cromo para todas as análises

Avaliação da prevalência das dores de cabeça primárias e seu relacionamento com sintomas de desordens temporomandibulares no campus da USP, na cidade de Bauru/SP / Primary headache prevalence and its relationship to temporomandibular disorders symptoms at USP campus, Bauru/SP

A prevalência das Cefaléias Primárias, das Desordens Temporomandibulares e da ocorrência simultânea destas patologias numa população adulta do campus da FOB/USP, na cidade de Bauru, SP foi investigada através de questionários para auto-entrevista, com perguntas e opções de resposta acerca das patologias citadas. Os resultados referentes à DTM e à Cefaléia Primária estiveram em concordância com a literatura, sendo de, aproximadamente 34 por cento a prevalência para as cefaléias e 60 por cento para a DTM. O relacionamento dessas informações foi o grande objetivo do trabalho. Encontrou-se que a ocorrência conjunta das duas patologias é freqüente, cerca de 54 por cento dos portadores de DTM têm também Cefaléia Primária, relacionamento este, estatisticamente significante quando aplicado o teste do qui-quadrado (p<0.01). O sexo feminino e a tensão emocional também se mostraram estatisticamente associados com tais patologias (p<0.01). Ainda se conseguiu detectar que a cefaléia do tipo tensional foi a mais freqüente, seguida das enxaquecas com aura e sem aura, com 61,61 por cento, 20,2 por cento e 18,2 por cento, respectivamente. As duas patologias embora com etiologias distintas são moduladas pelo mesmo sistema trigeminal, e portanto, necessitam de um diagnóstico preciso antes de qualquer procedimento irreversível

Avaliação do desajuste e do destorque em pilares protéticos com conexão tipo hexágono externo e interno / Evaluation of misfit and of the prothetic detorque internal and external hexagonal machined abutments

Objetivou-se com este trabalho avaliar o desajuste marginal e o efeito da aplicação de carga ciclica no destorque dos parafusos de retençao de pilares proteticos usinados, sobrefundidos e fundidos com conexao tipo hexagono externo (HE) e interno (HI). Foram avaliados 12 pilares proteticos para cada grupo com HE: (Al) usinados em titanio: (A2) com cinta metalica em paladio-prata, sobrefundidos com paladio-prata; (A3) plasticos fundidos em NiCr e (A4) plasticos fundidos em CoCr; e 12 pilares proteticos para cada grupo com HI: (Bl) usinados em titanic) e (B2) com cinta metalica em paladio-prata. sobrefundidos com paladio-prata. Foram reaiizadas analises de desajuste marginal (profundidade de fenda, desajuste vertical e horizontal) e de desajuste rotacional na interface implante/pilar protetico. Os valores de destorque foram registrados antes e depois da aplicagao de cargas ciclicas. As medias de cada grupo, para cada analise, foram calculadas e comparadas com ANOVA, Student-Newman Keuls (p < 0,05). Os resultados obtidos foram: profundidade de fenda (pm): (Al) 54.1 '+OU-' 127,75, (A2) 49,4'+OU-'36,56, (A3) 21,2'+OU-'21.36; (A4) 33.1'+OU-'23,81.. (Bl) 8.4'+OU-'13,74 e (B2) 34,9'+OU-'20,49: desajuste horizontal (pm): (Al) 89,1 '+OU-' 14,15, (A2) 39.2 '+OU-' 16.87, (A3) 13,5 '+OU-' 9,48, (A4) 23,0 '+OU-' 21,42, (B1) 10,9 '+OU-" 5.68 e (B2) 18.2 '+OU-' 10,31; desajuste vertical (pm): (Al) 5,6 '+OU-' 6,46, (A2) 11,1 '+OU-' 8,22, (A3) 8,0 9,35, (A4) 6,9 = 3,78, (B1) 2,1 T 3,21 e (B2) 12,1 '+OU-' 4,75; desajuste rotacional (em graus): (Al) 1.2 T 0,57. (A2) 1,8 '+OU-' 1,31, (A3) 2,0 = 0,73, (A4) 2,8 '+OU-' 1,14, (B1) 2.8 '+OU-' 1,08 e (B2) 2,0 1,03; destorque inicial (%): (Al) 92,3 '+OU-'3,0, (A2) 81,6 '+OU-' 5,0. (A3) 86,4 '+OU-' 4,6. (A4) 84,0 '+OU-' 7.7, (Bl) 88,8 '+OU-' 6,8 e (B2) 84,9 '+OU-' 2,4 e destorque final (%): 41,1 '+OU-' 19.3, (A2) 19,8 '+OU-' 13,0, (A3) 27,9 '+OU-' 6,5, (A4) 7,5 '+OU-' 16,2. (B1) 17,1 '+OU-' 16,2 e (B2) 23,3 '+OU-' 10.9...