RESUMEN
OBJECTIVE: The aim was to evaluate the internal adaptation of composite restorations in cusp-weakened Class I preparations restored by incremental, bi-layered, and bulk-fill techniques using a microcomputed tomography analysis (micro-CT). METHODS: Sixty sound extracted human third molars were prepared with standardized cusp-weakened Class I cavity preparations and divided into six groups (n=10). Two groups were restored using an incremental oblique technique with a nanofilled (Filtek Supreme XT, 3M Oral Care, St Paul, MN, USA) and a nanohybrid composite (GrandioSO, VOCO, Cuxhaven, Germany). The other two groups were restored using a bi-layered technique with a bulk-fill flowable composite base (Filtek Bulk Fill Flowable, 3M Oral Care; X-tra Base bulk-fill flowable, VOCO) covered with the conventional composite of the same type. In the remaining groups, teeth were restored with a single-increment technique using bulk-fill full-body composites (Filtek Bulk Fill Posterior, 3M Oral Care; Admira Fusion, VOCO). All teeth were subjected to thermocycling (20,000 cycles, 5°C and 55°C) and mechanical loading (250,000 cycles, 2.5 Hz, 50 N) before analysis of internal adaptation by micro-CT. One-way analysis of variance (ANOVA) and the Games-Howell test were used to analyze the percentage and volume of internal gaps (p<0.05). RESULTS: There was found to be significantly higher internal adaptation for the nanofilled composite used incrementally or associated with a flowable base compared with the nanohybrid composite used incrementally (p=0.002). CONCLUSIONS: Bulk-fill and bi-layered techniques performed similarly in terms of internal adaptation for both types of composites. The incremental technique with the nanofilled composite demonstrated a higher internal adaptation than with the nanohybrid composite.
Asunto(s)
Materiales Dentales , Restauración Dental Permanente , Resinas Compuestas/uso terapéutico , Preparación de la Cavidad Dental/métodos , Restauración Dental Permanente/métodos , Humanos , Ensayo de Materiales , Microtomografía por Rayos XRESUMEN
PURPOSE: The aim of this study was to evaluate the effect of adhesive strategy and time on the microtensile bond strength of a computer-aided design/computer-aided manufacturing (CAD/CAM) composite to dentin. METHODS AND MATERIALS: Sixty CAD/CAM composite blocks were bonded to human dentin with simplified bonding agents using etch-and-rinse and self-etching approaches and amine-based and amine-free resin cements, with and without the application of a dual-cure activator (DCA; n=10): SBP-ARC (Adper Single Bond Plus + RelyX ARC), SBP-RXU (Adper Single Bond Plus + RelyX Ultimate), SBP-DCA-RXU (Adper Single Bond Plus + DCA + RelyX Ultimate), SBU-ARC (Scotchbond Universal + RelyX ARC), SBU-RXU (Scotchbond Universal + RelyX Ultimate), and SBU-DCA-ARC (Scotchbond Universal + DCA + RelyX ARC). Each specimen was light cured for 40 seconds under load and stored in distilled water at 37°C for seven days. Stick-shaped specimens (1.0 mm2) were obtained. Half of the specimens underwent microtensile bond strength testing, and the other half were subjected to the same tests after six months of storage. Failure mode was determined using an optical microscope (40×). The data were analyzed by a two-way analysis of variance followed by the Games-Howell test and Student t-test (preset alpha of 0.05). RESULTS: After seven days, SBU-RXU presented the highest mean bond strength, statistically different from only SBU-ARC (p<0.05). Most of the groups exhibited a statistically significant reduction in bond strength after 6 months (p<0.05), except SBP-RXU and SBU-ARC (p>0.05). CONCLUSION: The adhesive strategy, with different associations between adhesive systems and resin cements, as well as the use of a DCA, affected the bond strength of both amine-free and amine-based resin cements to a CAD/CAM composite.
Asunto(s)
Recubrimiento Dental Adhesivo , Resinas Compuestas , Diseño Asistido por Computadora , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Humanos , Ensayo de Materiales , Cementos de Resina , Resistencia a la TracciónRESUMEN
PURPOSE: To evaluate the cement line thickness and the interface quality in milled or injected lithium disilicate ceramic restorations and their influence on marginal adaptation using different cement types and different adhesive cementation techniques. METHODS AND MATERIALS: Sixty-four bovine teeth were prepared for full crown restoration (7.0±0.5 mm in height, 8.0 mm in cervical diameter, and 4.2 mm in incisal diameter) and were divided into two groups: CAD/CAM automation technology, IPS e.max CAD (CAD), and isostatic injection by heat technology, IPS e.max Press (PRESS). RelyX ARC (ARC) and RelyX U200 resin cements were used as luting agents in two activation methods: initial self-activation and light pre-activation for one second (tack-cure). Next, the specimens were stored in distilled water at 23°C ± 2°C for 72 hours. The cement line thickness was measured in micrometers, and the interface quality received scores according to the characteristics and sealing aspects. The evaluations were performed with an optical microscope, and scanning electron microscope images were presented to demonstrate the various features found in the cement line. For the cement line thickness, data were analyzed with three-way analysis of variance (ANOVA) and the Games-Howell test (α=0.05). For the variable interface quality, the data were analyzed with the Mann-Whitney U-test, the Kruskal-Wallis test, and multiple comparisons nonparametric Dunn test (α=0.05). RESULTS: The ANOVA presented statistical differences among the ceramic restoration manufacturing methods as well as a significant interaction between the manufacturing methods and types of cement (p<0.05). The U200 presented lower cement line thickness values when compared to the ARC with both cementation techniques (p<0.05). With regard to the interface quality, the Mann-Whitney U-test and the Kruskal-Wallis test demonstrated statistical differences between the ceramic restoration manufacturing methods and cementation techniques. The PRESS ceramics obtained lower scores than did the CAD ceramics when using ARC cement (p<0.05). CONCLUSIONS: Milled restorations cemented with self-adhesive resin cement resulted in a thinner cement line that is statistically different from that of CAD or pressed ceramics cemented with resin cement with adhesive application. No difference between one-second tack-cure and self-activation was noted.
Asunto(s)
Diseño Asistido por Computadora , Coronas , Adaptación Marginal Dental , Porcelana Dental/química , Diseño de Prótesis Dental , Cementos de Resina/química , Animales , Bisfenol A Glicidil Metacrilato , Bovinos , Microscopía Electrónica de Rastreo , Polietilenglicoles , Ácidos PolimetacrílicosRESUMEN
OBJECTIVES: To assess total Streptococci (TS) counts and biofilm mass over tooth-tissue-borne palatal expander (TTBPE), as well as the effect of chlorhexidine (CHX) mouth rinse on these variables. DESIGN: A cross-sectional study design employed clinical procedures and laboratorial techniques. SETTING AND SAMPLE POPULATION: Patients who had TTBPE removal indicated were divided into two groups: a CHX group (n = 26) in which three times a day of 0.2% CHX digluconate mouth rinses were prescribed 7 days before TTBPE removal; and a control (CON) group (n = 25) in which no antimicrobial treatment was applied. EXPERIMENTAL VARIABLE: 'Gender', 'Age', and 'TTBPE wear time' were recorded. After TTBPE removal, biofilm mass was determined by the difference between (TTBPE + biofilm) and (TTBPE only) masses. TS counts were determined by biofilm suspension followed by progressive dilutions and culture on Mitis Salivarius agar with incubation at 37 degrees C for 72 h. OUTCOME MEASURE: Biofilm mass (mg) and Colony Forming Units of TS / mg of biofilm (CFU-TS / mg) were calculated. Results - Total Streptococci mean values in CHX (6.77 x 10(6)CFU-TS / mg) were statistically lower (p < 0.01) than those in CON (3.82 x 10(7)CFU-TS / mg), but there was no statistical difference (p > 0.05) between CHX (168.88 mg) and CON (182.04 mg) masses nor statistical correlation (p > 0.05) between biofilm mass and CFU-TS / mg in the two groups. CONCLUSION: Chlorhexidine reduces the TS counts in TTBPE, but has no effect on biofilm mass.
Asunto(s)
Antiinfecciosos Locales/farmacología , Biopelículas/efectos de los fármacos , Clorhexidina/análogos & derivados , Antisépticos Bucales/farmacología , Aparatos Ortodóncicos/microbiología , Técnica de Expansión Palatina/instrumentación , Streptococcus/efectos de los fármacos , Adolescente , Niño , Clorhexidina/farmacología , Recuento de Colonia Microbiana , Estudios Transversales , Femenino , Humanos , MasculinoRESUMEN
BACKGROUND AND OBJECTIVE: Chronic kidney disease (CKD) is a complex disorder, which results in several complications involving disturbance of mineral metabolism. Periodontal disease is an infectious disease that appears to be an important cause of systemic inflammation in CKD patients. Periodontal disease is characterized by clinical attachment loss (CAL) caused by alveolar bone resorption around teeth, which may lead to tooth loss. Osteoprotegerin (OPG) is a key regulator of osteoclastogenesis. Polymorphisms are the main source of genetic variation, and single nucleotide polymorphisms (SNPs) have been reported as major modulators of disease susceptibility. The aim of this study was to investigate the association of a polymorphism located at position -223 in the untranslated region of the OPG gene, previously known as -950, with susceptibility to CKD and periodontal disease. MATERIAL AND METHODS: A sample of 224 subjects without and with CKD (in hemodialysis) was divided into groups with and without periodontal disease. The OPG polymorphism was analyzed by polymerase chain reaction and restriction fragment length polymorphism. RESULTS: No association was found between the studied OPG polymorphism and susceptibility to CKD or periodontal disease. CONCLUSION: It was concluded that polymorphism OPG-223 (C/T) was not associated with CKD and periodontal disease in a Brazilian population. Studies on other polymorphisms in this and other genes of the host response could help to clarify the involvement of bone metabolism mediators in the susceptibility to CKD and periodontal disease.