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.

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.

Uso racional de técnicas cirúrgicas implantares e periodontais para reabilitação na zona estética com coroas cerâmicas e metalocerâmicas / Rational use of periodontal and implant surgical techniques to rehabilitate the esthetic zone with all-ceramic and metalloceramic crowns ­ a case report

O objetivo deste trabalho foi relatar um caso clínico onde o planejamento reverso e o uso racional das cirurgias implantares e periodontais mostraram-se fundamentais no preparo para reabilitação da zona estética com coroas cerâmicas e metalocerâmicas. Uma paciente de 32 anos apresentava estética pobre, como ausências dentárias isoladas e perda de tecido mole/duro na região dos caninos superiores. O tratamento foi dividido em cinco etapas: 1) coroas provisórias e correção do plano oclusal e corredor bucal; 2) expansão da crista do rebordo e implantes conexão cone-morse/platform-switching (em dois estágios); 3) gengivoplastia; 4) reabertura e cirurgias gengivais (gengivectomia, enxerto ósseo/de tecido conjuntivo, divisão de papilas); e 5) condicionamento e colocação das coroas cerâmicas defi nitivas nos dentes (cimento resinoso) e metalocerâmicas (cimento fosfato de zinco) sobre os implantes. O desenvolvimento deste caso está baseado no uso da biomecânica de interface implante/pilar que confere os menores valores de reabsorção óssea ao longo do tempo, fornecendo restaurações definitivas com aspecto natural, e ainda apoiado por uma revisão sistemática demonstrando a eficácia do tecido conjuntivo subepitelial no aumento da largura queratinizada ao redor dos implantes. A finalização obtida é esteticamente aceitável e durável, muito desejável na região anterior da maxila.

The objective of this study was to report a case where the reverse planning and the rational use of implant and periodontal surgical protocols were fundamental to prepare the rehabilitation in the esthetic zone with all-ceramic and metalloceramic crowns. A 32 years-old patient had poor aesthetics, single-tooth defi cits, and soft/hard tissue losses in the region of the upper canines. After a concise planning, the treatment was divided into fi ve steps: 1) temporary crowns, correction of occlusal plane and buccal corridor; 2) ridge expansion, morse cone/platform-switching dental implants (two-stage procedure); 3) gingivoplasty; 4) implant exposure and gingival surgeries (gingivectomy, bone graft/connective tissue grafts, pedicle flaps); and 5) tissue conditioning and cementation of all-ceramic (resin cement) over teeth and metalloceramic (zinc phosphate cement) over the implant abutments. The development of this case is based on the use of a biomechanical implant interface/abutment which gives lower values of bone resorption over time, providing final restorations with a natural aspect, and still supported by a systematic review demonstrating the effectiveness of subepithelial connective tissue grafts to increase the width of the keratinized peri-implant mucosa. The outcome is esthetically acceptable and has long-term quality, a very desirable condition in the anterior maxilla.

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.

The effect of casting procedures on rotational misfit in castable abutments.

PURPOSE: Misfit of implant components has been linked to restorative complications such as screw loosening. Although previous studies have shown a correlation between rotational misfit and screw loosening, the impact of casting procedures on rotational misfit is lacking. The aim of this in vitro study was to evaluate the effect of casting procedures on rotational misfit of cast abutments when compared to machined titanium abutments. MATERIALS AND METHODS: Forty-eight external hexagonal implants and 48 abutments were placed in 4 groups of 12 samples each: (1) machined titanium abutments, (2) premachined palladium abutments cast-on with palladium, (3) plastic burnout abutments cast with nickel chromium, and (4) plastic burnout abutments cast with cobalt chromium. Rotational misfit between the external hexagon of the implant and the internal hexagon of the abutment was measured using standardized techniques and recorded in degrees. Mean values for each group were analyzed with analysis of variance and Tukey test. RESULTS: The mean rotational misfit was 1.21 +/- 0.57 degrees for machined titanium abutments, 1.77 +/- 130 degrees for cast-on abutments, 1.98 +/- 0.72 degrees for cast NiCr abutments, and 2.79 +/- 1.13 degrees for cast CoCr abutments. Significantly greater rotational misfit was recorded with cast CoCr abutments when compared to machined titanium abutments (P < .05). CONCLUSION: Rotational misfit was less than 2 degrees for all groups except for cast CoCr abutments, which demonstrated a significantly greater rotational misfit.

A classification system to measure the implant-abutment microgap.

PURPOSE: A large microgap at the implant-abutment interface has been reported to result in adverse effects, including screw loosening, abutment rotation, and abutment fracture. However, a standardized classification of the implant-abutment interface has not been established. The purposes of this investigation were (1) to propose a classification system based on the horizontal and vertical microgap of the implant-abutment interface and (2) to compare the implant-abutment interface in 4 groups of abutments. MATERIALS AND METHODS: Forty-eight randomly selected external hexagonal implants were paired with (1) machined titanium abutments, (2) premachined palladium abutments cast-on with palladium alloy, (3) plastic burnout abutments cast with nickel chromium alloy, and (4) plastic burnout abutments cast with cobalt chromium alloy. A comparison of the horizontal and vertical microgaps at the implant-abutment interface was completed at 8 locations on each specimen to the nearest micrometer using an optical microscope with a magnification of 150x. Group means and significant differences between groups were determined by analysis of variance and Tukey multiple-comparisons post-hoc analysis. P < .05 was the threshold for statistical significance. RESULTS: There was no significant difference between groups with respect to vertical misfit. For horizontal misfit, machined titanium abutments presented significantly higher horizontal misfit compared to other groups (P < .001). Premachined cast-on abutments had significantly higher horizontal misfit than cast NiCr abutments (P < .001). In the proposed classification system, 23% of all sites measured at the implant-abutment interface had an ideal relationship, 34% had a horizontal discrepancy only, 4% had a vertical discrepancy only, and 39% had both vertical and horizontal discrepancies. CONCLUSION: The proposed implant-abutment classification system demonstrated a way to characterize and compare the microgap at the implant-abutment interface.

Effect of casting procedures on screw loosening in UCLA-type abutments.

BACKGROUND: Screw loosening of implant restorations continues to be a complication in implant prosthodontics. Screw joints are subjected to a loss of initially applied torque because of friction and component misfit. It has been suggested that the loss of applied torque is less in machined metal abutments than in cast plastic abutments. PURPOSE: This study compared the loss of applied torque (detorque) values in machined titanium and in cast UCLA-type abutments for external hex abutment/implant interface. MATERIALS AND METHODS: Four groups of 12 samples each were evaluated: (1) machined titanium abutments, (2) premachined palladium abutments cast with palladium, (3) plastic abutments cast with nickel-chromium, and (4) plastic abutments cast with cobalt-chromium. Each abutment was torqued to 30 Ncm according to the manufacturer's instructions and detorqued three times. The mean loss of applied torque (detorque) was recorded as a percentage of the torque applied. Group means were calculated and compared using ANOVA and Tukey's LSD test. RESULTS: Mean detorque values were (1) 92.3 +/- 2.9%, (2) 81.6 +/- 5.0%, (3) 86.4 +/- 4.6%, and (4) 84.0 +/- 7.0%. Machined abutments demonstrated significantly greater detorque values compared with all cast groups (p < 0.05). No significant differences were found among cast groups. CONCLUSION: Machined abutments retained a significantly greater percentage of torque compared with cast abutments. Casting procedures decrease the percentage of applied torque, which may influence final screw joint stability.

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

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.

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...

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

Ortodontia aplicada à implantologia - um tratamento multidisciplinar / Implants and orthodontics - a multidisciplinary treatment

Na atuação multidiscplinar, a intervenção ortodôntica mais comum é a Ortodontia pré-protética, quando se realiza a movimentação dentária para viabilizar a colocação de próteses convencionais ou próteses sobre implantes, pela redistribuição dos espaços protéticos. Nesse sentido, a Ortodontia trouxe grandes contribuições às demais áreas da odontologia, destacando-se a Prótese, Periodontia e Implantologia. Com a popularização dos implantes, a procura deste tipo de tratamento tornou-se bastante comum. Entretanto, o caso nem sempre está pronto para a fase cirúrgica do implante, necessitando de um planejamento integrado. No presente caso a abordagem multidisciplinar incluindo as áreas de Cirurgia, Ortodontia, Implante e Prótese possibilitaram a harmonia oclusal e estética do paciente

Programa de prevençäo do câncer bucal no município de Bauru, através do auto-exame / Oral cancer prevention through self-examination programme in Bauru - Säo Paulo

No município de Bauru, realizou-se um trabalho sobre prevençäo de câncer bucal, o qual constou de palestras e apresentaçäo de "posters" sobre câncer bucal e de como fazer o auto-exame da boca para detecçäo precoce de lesöes bucais. Após as palestras, os pacientes foram examinados nos Postos de Saúde de cada bairro visitado; ao final do estudo, observou-se que várias lesöes da mucosa bucal foram detectadas nos pacientes examinados, o que evidenciou a necessidade de o paciente fazer periodicamente um auto-exame da boca e que todo programa de saúde bucal deva incluir o diagnóstico precoce do câncer bucal