“In vitro” wear behavior of extracoronal precision attachments

The objective of this study was to evaluate the retentive ability and weight change of two extracoronal attachments after repeated insertion/removal cycles. Material and methods: Two extracoronal attachments were used, one with plastic inserts and the other one with conventional metal-alloy. Initial retentive ability was checked under a 20kgf load cell at 5mm/min. The weight of the fixed/removable pairs was verified with an electronic mass comparator. Fixed/removable pairs were tested with an insertion/removal cycling machine, for 5800 cycles (corresponding to 5 years) at a speed of 32 rpm speed. Insertion/ removal cycles were performed under artificial saliva. Weight change and retentive ability of attachments were verified at baseline, six-month, one-year, two-year, three-year, four-year and five-year time intervals. The two-way ANOVA for repeated measurements test was used to verify possible interactions between precision attachment type and retentive ability/weight change over time. Statistically significant associations were found between attachment type and retentive ability over time (P=0.006). Metal-alloy group showed significant differences between baseline and first year (P=0.005), baseline and second year (P=0.001), and between baseline and five years (P=0.035) of insertion/removal cycles. In the plastic insert group, no significant differences were found over time. No statistically significant associations were found between precision attachment types and weight change over time (P=0.643). Initial retentive ability can not be standardized for both attachments; the metal-alloy showed better performance than the plastic insert after five years. Both attachments did not show weight change after five years of simulated use

Influência do tipo de parafuso, liga e da posição do cilindro na adaptação marginal das infra-estruturas sob implantes antes e após a soldagem a laser

Misfit at the abutment-prosthetic cylinder interface can cause loss of preload, leading to loosening or fracture of gold and titanium screws. OBJECTIVES: To evaluate the influence of screw type, alloy, and cylinder position on marginal fit of implant frameworks before and after laser welding. METHODS: After Estheticone-like abutments were screwed to the implants, thirty plastic prosthetic cylinders were mounted and waxed-up to fifteen cylindrical bars. Each specimen had three interconnected prosthetic components. Five specimens were one-piece cast in titanium and five in cobalt-chromium alloy. On each specimen, tests were conducted with hexagonal titanium and slotted gold screws separately, performing a total of thirty tested screws. Measurements at the interfaces were performed using an optical microscope with 5mm accuracy. After sectioning, specimens were laser welded and new measurements were obtained. Data were submitted to a four-way ANOVA and Tukey's multiple comparisons test (alpha=0.05). RESULTS: Slotted and hexagonal screws did not present significant differences regarding to the fit of cylinders cast in titanium, either in one-piece casting framework or after laser welding. When slotted and hexagonal screws were tested on the cobalt-chromium specimens, statistically significant differences were found for the one-piece casting condition, with the slotted screws presenting better fit (24.13µm) than the hexagonal screws (27.93 µm). Besides, no statistically significant differences were found after laser welding. CONCLUSIONS: 1) The use of different metal alloys do exert influence on the marginal fit, 2) The slotted and hexagonal screws play the exclusive role of fixing the prosthesis, and did not improve the fit of cylinders, and 3) cylinder position did not affect marginal fit values.A desadaptação na interface abutment-cilindro protético pode causar perda da pré-carga, levando ao afrouxamento ou fratura dos parafusos de ouro e titânio. OBJETIVOS: Avaliar a influência do tipo de parafuso, liga e posição do cilindro na adaptação marginal de infra-estruturas sobre implante antes e após a soldagem a laser. MÉTODOS: Após os abutments do tipo Estheticone serem aparafusados nos implantes, trinta cilindros protéticos de plástico foram montados e encerados com 15 barras cilíndricas. Cada espécime possuía três componentes protéticos interconectados. Cinco espécimes foram fundidos em monobloco com liga de titânio e liga de cobalto-crômio. Em cada espécime, os testes foram conduzidos com parafusos hexagonais de titânio e com parafusos de ouro com fenda, separadamente, num total de 30 parafusos testados. As medidas nas interfaces foram feitas com microscópio óptico com 5mm de precisão. Após o seccionamento, os espécimes foram soldados a laser e novas medidas obtidas. Os dados foram submetidos para análise com os testes ANOVA a quatro critérios e Tukey para comparações múltiplas (alfa=0,05). RESULTADOS: Os parafusos com fenda e hexágono não apresentaram diferenças significantes independente da adaptação dos cilindros fundidos em titânio, tanto em monobloco como após a soldagem a laser. Quando os parafusos com hexágono e fenda foram testados nos espécimes de cobalto-crômio, diferenças estatisticamente significantes foram encontradas na condição monobloco, com os parafusos fendidos apresentando melhor adaptação (24,13µm) do que os com hexágono (27,93 µm). Além disso, nenhuma diferença significante foi encontrada após a soldagem a laser. CONCLUSÕES: 1) O uso de diferentes ligas metálicas exerce influência nos resultados, 2) Os parafusos com hexágono e fenda somente possuem o papel de fixar a prótese, e não melhoram a adaptação dos cilindros e 3) a posição do cilindro não afetou os valores de adaptação marginal

Correlation between margin fit and microleakage in complete crowns cemented with three luting agents

Microleakage can be related to margin misfit. Also, traditional microleakage techniques are time-consuming. This study evaluated the existence of correlation between in vitro margin fit and a new microleakage technique for complete crowns cemented with 3 different luting agents. Thirty human premolars were prepared for full-coverage crowns with a convergence angle of 6 degrees, chamfer margin of 1.2 mm circumferentially, and occlusal reduction of 1.5 mm. Ni-Cr cast crowns were cemented with either zinc phosphate (ZP) (S.S. White), resin-modified glass-ionomer (RMGI) (Rely X Luting Cement) or a resin-based luting agent (RC) (Enforce). Margin fit (seating discrepancy and margin gap) was evaluated according to criteria in the literature under microscope with 0.001 mm accuracy. After thermal cycling, crowns were longitudinally sectioned and microleakage scores at tooth-cement interface were obtained and recorded at ×100 magnification. Margin fit parameters were compared with the one-way ANOVA test and microleakage scores with Kruskal-Wallis and Dunn's tests (alpha=0.05). Correlation between margin fit and microleakage was analyzed with the Spearman's test (alpha=0.05). Seating discrepancy and marginal gap values ranged from 81.82 µm to 137.22 µm (p=0.117), and from 75.42 µm to 78.49 µm (p=0.940), respectively. Marginal microleakage scores were ZP=3.02, RMGI=0.35 and RC=0.12 (p;0.05). Conclusion: Margin fit parameters and microleakage showed no strong correlations; cast crowns cemented with RMGI and RC had lower microleakage scores than ZP cement

Adaptação marginal na interface intermediário-cilindro antes e após as sobrefundições

The aim of this study was to measure marginal fit at cylinder-abutment interface, before and after overcasting procedure. A hexagonal implant was fixed to a stainless steel base and a Estheticone-like abutment used during all the experiment. Before casting procedure, gold (Group I) and Ni-Cr-Be (Group II) premachined cylinders were tightened to the abutment with gold and titanium screws (in both groups), with 10Ncm and 20Ncm torque values for the same screw type. Vertical measures were taken at the light microscope (Mitutoyo 5050, Tokyo, Japan) three times in six different parts along the abutment-cylinder interface for each torque value. Cylinders were overcast with Ag-Pd (Group I) or Ni-Cr-Be (Group II) alloy. After casting, the same measures and torque values were repeated. Intragroup differences (10 or 20Ncm torque values, before and after casting) and intergroup differences (10 and 20Ncm torque values, before or after casting) were analyzed by the Paired t Test; (pO objetivo deste estudo foi medir a adaptação marginal na interface intermediário-cilindro, antes e após a sobrefundição. Um implante do tipo hexágono externo afixado numa base de aço inoxidável e um intermediário do tipo Estheticone foram usados durante todo o experimento. Antes das fundições, cilindros pré-usinados de ouro (Grupo I) e de Ni-Cr-Be (Grupo II) foram aparafusados ao intermediário com parafusos de ouro e titânio em ambos os grupos, com torques de 10Ncm e 20Ncm para o mesmo tipo de parafuso. As medidas verticais foram feitas num microscópio óptico (Mitutoyo 5050, Tóquio, Japão) três vezes em seis locais diferentes ao longo da interface intermediário-cilindro para cada valor de torque. Os cilindros foram encerados e fundidos tanto em liga de Ag-Pd (Grupo I) ou liga de Ni-Cr-Be (Grupo II). Após as fundições, as mesmas medidas e os mesmos valores de torque foram repetidos. As diferenças intra-grupo (torques de 10 ou 20Ncm, antes e após as fundições) e as diferenças inter-grupos (torques de 10 e 20Ncm, antes ou após as fundições) foram analisadas pelo teste t pareado (

Influência da ciclagem com cargas dinâmicas na microinfiltração de coroas metalocerâmicas cimentadas com três tipos de cimento

O propósito deste estudo foi avaliar "in vitro" as mensurações e possíveis correlações entre discrepância de assentamento, abertura marginal e padrão de microinfiltração, em coroais metalocerâmicas cimentadas com três tipos de agentes cimentantes: fosfato, ionômero e cimento resinoso dual. Trinta dentes pré-molares humanos extraídos foram preparados para coroas metalocerâmicas e as fundições foram realizadas com liga de Ni-Cr. As amostras foram divididas em três grupos, de acordo com o agente cimentante e a cimentação foi realizada sob uma carga de 5Kg por 10 minutos e as amostras armazenadas em água por 24hs. A discrepância de assentamento foi registrada antes e após a cimentação em um microscópio óptico com precisão de 0,001micrometro. Metade dos espécimes dentro de cada grupo foi submetida ao teste de fadiga cíclica (50.000 ciclos, 2,5Hz). As coroas foram seccionadas longitudinalmente no sentido vestíbulo-lingual e na interface coroadente-cimento foi aplicado um corante (rodamina B) por 15 segundos. A penetração do corante foi quantificada ao longo da interface sob um microscópio óptico (80 vezes de aumento) e, posteriormente, as amostras foram preparadas para microscopia eletrônica de varredura a fim de quantificar a abertura marginal e a qualidade da interface. Os resultados de discrepância de assentamento foram maiores para o cimento fosfato de zinco, seguido do ionômero de vidro e resinoso, sem diferença estatística. Foram encontradas diferenças estatisticamente significantes entre a discrepância de assentamento e a abertura marginal para os três cimentos. Os resultados de infiltração foram maiores para o cimento fosfato de zinco, seguido do ionômero de vidro e resinoso, com diferenças estatisticamente significantes. A ciclagem mecânica aumentou a infiltração marginal para o cimento fosfato de zinco, com diferença estatisticamente significativa em relação ao cimento ionomérico e resinoso. A análise ao microscópio eletrônico de varredura detectou melhor qualidade de união na interface dente-cimento para o sistema resinoso, seguido pelo cimento ionomérico e resinoso.The purpose of this study was to verify "in vitro" measures and possible correlations between seating discrepancy, marginal opening and microleakage pattern under total metallic crowns cemented with three types of luting agents: phosphate, glass-ionomer and resin dual cement. Thrirty extracted human premolars teeth were prepared for total metalloceramic crowns and castings obtained with a Ni-Cr alloy. Samples were ramdomly assigned for three groups in according to each luting agent: zinc phosphate (S.S.White), resin-modified glass-ionomer (Vitremer-3M) or a dual resin cement (Enforce-Dentsply). Cementation was done under a 49N load for 10 minutes and water stored for 24hs. Vertical discrepancy was registered before and after cementation in an optical microscopy with the accuracy of 0,001mm). Half of the specimens within each group was submitted to a cyclic loading test (50000 cycles, 2,5Hz). Crowns were longitudinally seccionated in a bucco- lingual plane at the tooth-cement-crown interface and dye solution (rodhamine B) was apllied to tooth-cement- interface for 15 seconds The linear stain penetration along tooth-cement was quantified. under a light microscope (80X magnification) and then samples were prepared for scanning electronic microscope in order to quantify marginal opening and the quality of interface. The results for seating discrepancy were higher for zinc phosphate, followed by glass-ionomer and resin cement, with no statistical difference. Statistically significant differences were found between seating discrepancy and marginal opening for the three cements. Microleakage results were higher for zinc phosphate, followed by glass-ionomer and resin cement, with statiscally significant differences. Fatigue loading rinsed marginal leakage for zinc pohsphate, with statiscally significant difference in respect to glassionomer and resin cement. Scanning electron microscope analysis showed better marginal quality at the tooth-cement-restoration interface for resinous cement,followed by glass-ionomer and zinc phosphate cement

Influence of microleakage technique, simulated pulpal pressure, water storage, and cyclic fatigue on marginal integrity and microleakage of In-Ceram alumina crowns

Objetivos: verificar a influência da técnica de microinfiltração, pressão pulpar simulada, armazenamento e fadiga cíclica na microinfiltração e integridade marginal das coroas In-Ceram alumina. Material e métodos: Dentes pré-molares superiores humanos de dimensões semelhantes receberam preparos para coroa total com 4mm de altura, 6 graus de convergência e 2mm de desgaste axial e oclusal. Coroas de In-Ceram alumina com 0,5mm de espessura foram obtidas e cimentadas com Panavia F/Clearfil SE Bond (PAN-SE) e/ou Rely XARC/Adper Single Bond 2 (REL-SB). Quatro hipóteses foram testadas: 1) Ausência de diferença na microinfiltração entre uma nova técnica sugerida para verificar a microinfiltração, quando comparada à técnica convencional, 1.1) Verificar se a nova técnica é adequada para estudos laboratoriais de microinfiltração, 2) A pressão pulpar simulada (15cmH2O) não altera a microinfiltração; 3) O armazenamento (90 dias) / fadiga cíclica (500.000 ciclos, 2Hz, 5kg) não têm influência na microinfiltração marginal e 4) O armazenamento/fadiga cíclica não influenciam a integridade marginal das coroas. Grupos controle foram constituídos em todos os experimentos. Resultados: 1) Nenhuma diferença estatisticamente significante foi detectada entre as duas técnicas testadas para analisar a microinfiltração dentro de cada conjunto cimento/adesivo (p>0,05); 2) A pressão pulpar simulada alterou significativamente a microinfiltração nos conjuntos PAN-SE (Mann-Whitney, p=0,025) e REL-SB (Mann-Whitney, p=0,014); 3) O armazenamento em água (Mann-Whitney, p=0,032) e armazenamento/fadiga cíclica (Mann-Whitney, p=0,008) aumentaram significativamente a microinfiltração no conjunto PAN-SE; 4) A perda de integridade marginal foi de 4% e 10% nos conjuntos REL-SB e PAN-SE, respectivamente. Conclusões: 1) não houve diferença na microinfiltração entre uma nova técnica sugerida para verificar a microinfiltração, quando comparada à técnica convencional, 1.1) A nova técnica parece adequada para estudos laboratoriais de microinfiltração; 2) O uso da pressão pulpar alterou significativamente os valores de microinfiltração para os dois cimentos/adesivos; 3) O armazenamento/fadiga cíclica mostrou influência na microinfiltração para o cimento Panavia F; 4) O armazenamento/fadiga cíclica não tiveram influência estatisticamente significante na integridade marginal dos cimentos/adesivos testados.Objectives: To verify the influence of microleakage technique, simulated pulpal pressure, water storage and cyclic fatigue on marginal integrity and microleakage of In-Ceram alumina crowns. Material and methods: Human premolar teeth of similar dimensions received complete crown preparation with a 6 convergence degree, 4mm-height and 2mm of axial and occlusal reduction. In-Ceram alumina copings 0.5mm-thick were obtained and cemented either with Panavia F/Clearfil SE Bond (PAN-SE) or Rely XARC/Adper Single Bond 2 (REL-SB). Four hypotheses were made: 1) No difference between a new technique and a standard one to verify microleakage, 1.1) To verify if a new microleakage technique is adequate for laboratorial studies; 2) Simulated pulpal pressure (15cmH2O) does not alter microleakage; 3) Water storage (90 days) / cyclic fatigue (500.000 cycles, 2Hz, 5kg) does not have influence on microleakage and 4) Water storage/cyclic fatigue does not influence marginal integrity of crowns. Control groups were established for all experiments. Results: 1) No statistically significant difference was detected between the two techniques to assess microleakage in each cement/adhesive combination; 2) Simulated pulpal pressure significantly altered microleakage for PAN-SE (Mann-Whitney, p=0.025) and REL-SB (Mann-Whitney, p=0.014); 3) Water storage (Mann-Whitney, p=0.032) and water storage/cyclic fatigue (Mann-Whitney, p=0.008) significantly increased microleakage only in PAN-SE groups. These parameters were not decisive in REL-SB groups even with higher microleakage values, and 4) Loss of marginal integrity was of 4% and 10% in REL-SB and PAN-SE groups, respectively. Conclusions: 1) No differences on microleakage were observed when a new technique suggest to assess microleakage was compared to a standard one. 1.1) This new technique seems adequate for laboratorial microleakage studies; 2) Simulated pulpal pressure significantly altered microleakage values for both adhesives/cements; 3) Water storage/cyclic fatigue influenced on microleakage of Panavia F and 4) Water storage/cyclic fatigue did not have influence on marginal integrity of both adhesives/cements tested

Microbiologic and Clinical Findings of Implants in Healthy Condition and with Peri-Implantitis

To compare implants in healthy conditions and implants with peri-implantitis with regard to their clinical parameters and the microbiologic composition at the peri-implant sulcus, inside the implant connection, and the gingival sulcus of neighboring teeth. Materials and Methods: A cross-sectional study was performed including consecutive patients with implants in healthy conditions and with peri-implantitis. Clinical parameters for which patients were screened included bleeding on probing, pocket depth, and plaque index at six sites. Samples for microbiologic analysis were obtained from three locations: the peri-implant sulcus, inside the implant connection, and the gingival sulcus of neighboring teeth. Quantitative real-time polymerase chain reaction (PCR) was carried out for total counts of 10 microorganisms: Aggregatibacter actinomycetemcomitans, Porphyromona gingivalis, Tanerella forsythia, Tanerella denticola, Prevotela intermedia, Peptostreptococcus micros, Fusobacterium nucleatum, Campylobacter rectus, Eikenella corrodens, and Candida albicans. The response variables were the percentage of positive sites and total bacterial counts. Results: One hundred twenty-two implants in 57 patients were analyzed in the healthy group and 113 implants in 53 patients in the peri-implantitis group. Differences between the groups were statistically significant for bruxism, probing pocket depth, bleeding on probing, and radiographic bone level. Orange complex species (P intermedia, P micros, F nucleatum) were the most prevalent in the three types of sites for both groups, and prevalence values were higher in the peri-implantitis group. Differences in prevalence between groups were more marked inside the connection than in the peri-implant sulcus. Absolute loads of most microbes and total bacterial counts were higher for the peri-implantitis group in the three locations. Again, differences were bigger inside the connection than at the peri-implant sulcus. Significant interactions were found for prevalence and absolute microbial loads between groups and locations, and for the interaction of group x location. Conclusion: Clinical and microbiologic differences were observed between healthy subjects and those with peri-implantitis. Microbiologic differences between groups were more marked inside the connection than in the peri-implant sulcus. The potential role of the implant connection as a microbial reservoir for peri-implant diseases and in the outcome of their treatment should be confirmed with further studies

Association between sleep bruxism and temporomandibular disorders: A polysomnographic pilot study

The aim of this study was to verify the association between sleep bruxism (SB) and temporomandibular disorders (TMD) in a sample of 14 TMD patients and 12 healthy control subjects. All participants were evaluated using a clinical questionnaire, visual analog scale (VAS) for TMJ/muscle palpation, and by functional examination. The experimental group was divided into three TMD subgroups: joint sounds and pain, muscular tenderness, and mixed diagnosis. All participants underwent polysomnographic recording (PSG). A second clinical examination was then carried out to verify the relationship between rhythmic masticatory muscle activity and pain/tenderness on the following morning. e experimental and control groups presented VAS mean scores of 36.85 +/- 23.73 mm and 0 mm, respectively. The presence of SB was neither associated with TMD (p>0.05) nor with pain on palpation (p>0.05). Further research with a more representative sample of each TMD subgroup is necessary to elucidate its interaction with SB

Association between rhythmic masticatory muscle activity during sleep and masticatory myofascial pain: A polysomnographic study

Aims: To test for an association between rhythmic masticatory muscle activity during sleep, as assessed according to polysomnographic criteria for sleep bruxism (RMMA-SB), and myofascial pain (MFP), as well as the chance of occurrence of MFP in patients with RMMA-SB. Methods: Thirty MFP patients (diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders) and 30 age- and gender-matcbed asymptomatic controls underwent a polysomnographic examination. Also, any self-reporting of daytime clenching (DC) was registered in 58 of these subjects. Results: Most MFP patients reported mild or moderate pain (46.67% and 43.33%, respectively), and only 3 (10%) reported severe pain. Pain duration ranged from 2 to 120 months (mean 34.67 +/- 36.96 months). Significant associations were observed between RMMA-SB and MFP as well as between DC and MFP. Conclusions: (1) RMMA-SB is significantly associated with MFP; (2) although RMMA-SB represents a risk factor for MFP, this risk is low; and (3) DC probably constitutes a stronger risk factor for MFP than RMMA-SB