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Bone Healing Around Dental Implants: Simplified vs Conventional Drilling Protocols at Speed of 400 rpm
Gil, Luiz Fernando; Sarendranath, Alvin; Neiva, Rodrigo; Marao, Heloisa F; Tovar, Nick; Bonfante, Estevam A; Janal, Malvin N; Castellano, Arthur; Coelho, Paulo G
PURPOSE: This study evaluated whether simplified drilling protocols would provide comparable histologic and histomorphometric results to conventional drilling protocols at a low rotational speed. MATERIALS AND METHODS: A total of 48 alumina-blasted and acid-etched Ti-6Al-4V implants with two diameters (3.75 and 4.2 mm, n = 24 per group) were bilaterally placed in the tibiae of 12 dogs, under a low-speed protocol (400 rpm). Within the same diameter group, half of the implants were inserted after a simplified drilling procedure (pilot drill + final diameter drill), and the other half were placed using the conventional drilling procedure. After 3 and 5 weeks, the animals were euthanized, and the retrieved bone-implant samples were subjected to nondecalcified histologic sectioning. Histomorphology, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) analysis were performed. RESULTS: Histology showed that new bone was formed around implants, and inflammation or bone resorption was not evident for both groups. Histomorphometrically, when all independent variables were collapsed over drilling technique, no differences were detected for BIC and BAFO; when drilling technique was analyzed as a function of time, the conventional groups reached statistically higher BIC and BAFO at 3 weeks, but comparable values between techniques were observed at 5 weeks; 4.2-mm implants obtained statistically higher BAFO relative to 3.75-mm implants. CONCLUSION: Based on the present methodology, the conventional technique improved bone formation at 3 weeks, and narrower implants were associated with less bone formation.
PMID: 28291851
ISSN: 1942-4434
CID: 2528702
Mg substituted apatite coating from alkali conversion of acidic calcium phosphate
Navarro da Rocha, Daniel; Cruz, Leila Rosa de Oliveira; de Campos, Jose Brant; Marcal, Rubens L Santana Blazutti; Mijares, Dindo Q; Coelho, Paulo G; Prado da Silva, Marcelo H
In this work, two solutions were developed: the first, rich in Ca2+, PO43- ions and the second, rich in Ca2+, PO43- and Mg2+, defined as Mg-modified precursor solution. For each Mg-modified precursor solution, the concentrations of Mg2+ ions were progressively increased by 5%, 10% and 15%wt. The aims of this research were to investigate the influence of magnesium ions substitution in calcium phosphate coatings on titanium surface and to evaluate these coatings by bioactivity assay in McCoy culture medium. The obtained coatings were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis, and the presence of Mg ions was confirmed by the inductively coupled plasma atomic emission spectroscopy (ICP) analysis. In vitro bioactivity assay in McCoy culture medium showed bioactivity after 14days in incubation for the HA and 10% Mg-monetite coatings. The high chemical stability of Mg-HA coatings was verified by the bioactivity assays, and no bone-like apatite deposition, characteristic of bioactivity, was observed for Mg-HA coatings, for the time period used in this study.
PMID: 27770910
ISSN: 1873-0191
CID: 2288502
Microcomputed Tomography Evaluation of Polymerization Shrinkage of Class I Flowable Resin Composite Restorations
Sampaio, C S; Chiu, K-J; Farrokhmanesh, E; Janal, M; Puppin-Rontani, R M; Giannini, M; Bonfante, E A; Coelho, P G; Hirata, R
The present study aimed to characterize the pattern and volume of polymerization shrinkage of flowable resin composites, including one conventional, two bulk fill, and one self-adhesive. Standardized class I preparations (2.5 mm depth x 4 mm length x 4 mm wide) were performed in 24 caries-free human third molars that were randomly divided in four groups, according to the resin composite and adhesive system used: group 1 = Permaflo + Peak Universal Bond (PP); group 2 = Filtek Bulk Fill + Scotchbond Universal (FS); group 3 = Surefil SDR + XP Bond (SX); and group 4 = Vertise flow self-adhering (VE) (n=6). Each tooth was scanned three times using a microcomputed tomography (muCT) apparatus. The first scan was done after the cavity preparation, the second after cavity filling with the flowable resin composite before curing, and the third after it was cured. The muCT images were imported into three-dimensional rendering software, and volumetric polymerization shrinkage percentage was calculated for each sample. Data were submitted to one-way analysis of variance and post hoc comparisons. No significant difference was observed among PP, FS, and VE. SX bulk fill resin composite presented the lowest values of volumetric shrinkage. Shrinkage was mostly observed along the occlusal surface and part of the pulpal floor. In conclusion, polymerization shrinkage outcomes in a 2.5-mm deep class I cavity were material dependent, although most materials did not differ. The location of shrinkage was mainly at the occlusal surface.
PMID: 27689769
ISSN: 1559-2863
CID: 2451912
Revisiting the role of implant design and surgical instrumentation on osseointegration
Chapter by: Coelho, PG; Bonfante, EA; Jimbo, R
in: Implant Aesthetics: Keys to Diagnosis and Treatment by
pp. 43-56
ISBN: 9783319507064
CID: 3410002
Reliability and failure modes of anterior monolithic CAD/CAM veneers
Romanini-Junior, J.C.; Bordin, D.; Reis, A.F.; Fardin, V.P.; Bonfante, E.A.; Hirata, R.; Coelho, P.C.
DOSS:125255004
ISSN: 0109-5641
CID: 2735972
Bioactivity assessment of calcium phosphate coatings
Navarro Da Rocha, D; De Oliveira Cruz, LR; Mijares, DQ; Blazutti Març, RLS; De Campos, JB; Coelho, PG; Prado Da Silva, MH
Nowadays, bioactive coatings or modifications on titanium surface have been tested in vitro and in vivo. In this study, two types of calcium phosphate coatings were produced by a chemical deposition method and their bioactivity assay in cell culture medium were investigated. The calcium phosphate coatings were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy with field emission gun (FEG-SEM) analyses. Titanium substrate was successfully coated with brushite using chemical deposition method and, after a second step of conversion, the hydroxyapatite coating was obtained. The hydroxyapatite coating showed a bioactivity property after 14 days' incubation in McCoy medium culture
SCOPUS:85000962021
ISSN: 1013-9826
CID: 2402922
Temperature influence on the calcium phosphate coatings by chemical method
Navarro Da Rocha, D; De Oliveira Cruz, LR; Mijares, DQ; Blazutti Març, RLS; De Campos, JB; Coelho, PG; Prado Da Silva, MH
The increasing interest in the use of brushite and monetite as resorbable calcium phosphate cements or graft materials is related to the fact of these phases being metastable under physiological environment, with higher solubility than hydroxyapatite phase. In this study, X-ray diffraction (XRD) and scanning electron microscopy with field emission gun (FEG-SEM) analyses were performed in order to assess the temperature influence on the production of calcium phosphate coatings by a chemical deposition method. Titanium substrates were successfully coated with brushite and monetite by a chemical deposition method and a brushite-monetite transformation was assessed with the increasing temperature. Brushite deposition was kinetically favored at low temperatures, whereas monetite was the major phase at higher temperatures
SCOPUS:85000978414
ISSN: 1013-9826
CID: 2402912
Effect of Mechanical Fatigue on the Bond Between Zirconia and Composite Cement
Vidotti, Hugo A; Carvalho, Ricardo M; Coelho, Paulo G; Zambuzzi, Willian F; Bonfante, Gerson; do Valle, Accácio L; Bonfante, Estevam A
PURPOSE:To examine the effect of mechanical fatigue on the bond strength of resin composite cemented to silica-coated yttria-tetragonal zirconia polycrystal ceramic (Y-TZP). MATERIALS AND METHODS:Ten Y-TZP blocks were polished down to 600-grit silicon carbide paper. Specimens were silica coated by airborne-particle abrasion with 30-μm silica-modified Al2O3 particles. Blocks were cleaned in an ultrasonic bath, and a dental adhesive was applied and light cured for 20 s. Pre-cured composite blocks were luted to treated Y-TZP surfaces with a dual-curing resin cement. Half of the samples (n = 5) were subjected to mechanical fatigue before trimming (fatigue group) and the other half tested 24 h after bonding procedures (control group). Forty-five beam-shaped samples with an approximately 1 mm2 cross-sectional area were prepared for each group and tested in microtensile mode at 0.5 mm/min. Fractographic analysis was performed by optical and scanning electron microscopy. Only specimens that failed at the interface area were considered for statistical analysis. Weibull distribution (95% confidence bounds) was used to determine the characteristic strength (σ0 in MPa) and Weibull modulus (m) for each group. Probability of survival was calculated over the range of loads until specimens failed. RESULTS:The control group showed σ0 = 45.91 MPa and m = 7.98, and the fatigue group σ0 = 43.94 MPa and m = 6.44 (p > 0.05). The probability of survival did not differ significantly between groups. CONCLUSIONS:Fatigue did not affect the bond strength between silica-treated Y-TZP intaglio surfaces and composite cement under these experimental conditions.
PMID: 29152618
ISSN: 1461-5185
CID: 3859362
Platelet-Rich Plasma (PRP): The Whole or Sum of Parts by Proteomics and Molecular Assays [Meeting Abstract]
He, L; Shen, Y; Liu, J; Zhong, J; Gong, Q; Zheng, J; Latridis, J; Lee, FY; Thomopoulos, S; Rodeo, S; Chen, M; Ahn, JA; Pei, JJ; Coelho, PG; Ling, J; Mao, JJ
ISI:000390569200146
ISSN: 1937-335x
CID: 2782382
Physicochemical characterization of three fiber-reinforced epoxide-based composites for dental applications
Bonon, Anderson J; Weck, Marcus; Bonfante, Estevam A; Coelho, Paulo G
Fiber-reinforced composite (FRC) biomedical materials are in contact with living tissues arising biocompatibility questions regarding their chemical composition. The hazards of materials such as Bisphenol A (BPA), phthalate and other monomers and composites present in FRC have been rationalized due to its potential toxicity since its detection in food, blood, and saliva. This study characterized the physicochemical properties and degradation profiles of three different epoxide-based materials intended for restorative dental applications. Characterization was accomplished by several methods including FTIR, Raman, Brunauer-Emmett-Teller (BET) Analysis, X-ray fluorescence spectroscopy, and degradation experiments. Physicochemical characterization revealed that although materials presented similar chemical composition, variations between them were more largely accounted by the different phase distribution than chemical composition.
PMID: 27612785
ISSN: 1873-0191
CID: 2238452