The Effect of Coating Patterns with Spinel-Based Investment on the Castability and Porosity of Titanium Cast into Three Phosphate-Bonded Investments

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diametral tensile strength and film thickness of an experimental dental luting agent derived from castor oil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparison of the Accuracy of Plastic and Metal Stock Trays for Implant Impressions

Purpose: This in vitro study evaluated the dimensional accuracy of two impression techniques (tapered and splinted) with two stock trays (plastic and metal) for implant-supported prostheses. Materials and Methods: A master cast with four parallel abutment analogs and a passive framework were fabricated. Polyvinyl siloxane impression material was used for all impressions with two metal stock trays and two plastic stock trays (closed and open trays). Four groups (tapered plastic, splinted plastic, tapered metal, and splinted metal) and a control group (master cast) were tested (n = 5 for each group). After the framework was seated on each of the casts, one abutment screw was tightened, and the marginal gap between the abutment and framework on the other side was measured with a stereomicroscope. The measurements were analyzed with the Kruskal-Wallis one-way analysis of variance on ranks test followed by the Dunn method. Results: The mean values (+/- standard deviations) for the abutment/framework interface gaps were: master cast, 32 +/- 2 mu m; tapered metal, 44 +/- 10 mu m; splinted metal, 69 +/- 28 mu m; tapered plastic, 164 +/- 58 mu m; splinted plastic, 128 +/- 47 mu m. No significant difference was detected between the master cast, tapered metal, and splinted metal groups or between the tapered and splinted plastic groups. Conclusions: In this study, the rigidity of the metal stock tray ensured better results than the plastic stock tray for implant impressions with a high-viscosity impression material (putty). Statistically similar results were obtained using tapered impression copings and splinted squared impression copings. The tapered impression copings technique and splinted squared impression copings technique with a metal stock tray produced precise casts with no statistically significant difference in interface gaps compared to the master cast. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:544-550.

Flexural Strength of Four Adhesive Fixed Dental Prostheses of Composite Resin Reinforced with Glass Fiber

Purpose: To evaluate the flexural strength of two fixed dental prosthesis (FDP) designs simulating frameworks of adhesive fixed partial prostheses, reinforced or not by glass fiber.Materials and Methods: Forty specimens, made with composite resin, were divided into 4 groups according to the framework design and the presence of fiber reinforcement: A1 - occlusal support; A2: occlusal support + glass fiber; B1: occlusal and proximal supports; B2: occlusal and proximal supports + glass fiber. The specimens were subjected to the three-point bending test, and the data were submitted to two-way ANOVA and Tukey's test (5%).Results: Group A2 (97.9 +/- 38 N) was statistically significantly different from all other experimental groups, presenting a significantly lower mean flexural strength.Conclusion: The use of glass fibers did not improve the flexural strength of composite resin, and designs with occlusal and proximal supports presented better results than designs simulating only occlusal support.

External Hexagon and Internal Hexagon in Straight and Offset Implant Placement: Strain Gauge Analysis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sobredentadura inmediata y con carga tardía: Revisión de la literatura

The oral rehabilitation of the patients toothless totals presents large difficulties, because diverse factors act limiting the treatment with complete dentures conventional, as severe reabsorption of the alveolar process, generating for the phonetic patient difficulties and of mastication, annoyance, retention lack and stability of the prosthesis. With the emergence of you implant them osseointegratin idealized by Prof o Branemark, these aspects were improved by means of the possibility of new treatment options, as the overdentures tissue-implant-supported. However, the protocol of Branemark demanded a period of scaring from three to six months, owing the patients to await this time for the placement of the final prosthesis. This way, the surgical technique of immediate load was proposed to abbreviate this period, improving the transition phase, at the same time that it reduces the problems psychological associates. This way, the objective of the present study is to carry out a literature revision about the works that used overdentures comparing immediate and late load, the best alternative and factors wrapped in the success of the procedure discussing. © 2008 1995, Editorial Ciencias médicas.

Accuracy of impression techniques for implants. Part 1 - Influence of transfer copings surface abrasion

Purpose: This study evaluated the influence of surface abrasion of transfer copings to obtain a precise master cast for a partially edentulous restoration with different inclinations. Materials and Methods: Replicas (N = 30) of a metal matrix (control group) containing two implants at 90° and 65° in relation to the benchtop were obtained using a polyether impression material and three impression techniques: square impression copings splint with dental floss and autopolymerizing acrylic resin (TRS), square impression copings abraded with aluminum oxide (TA), and square impression copings abraded with aluminum oxide and adhesive-coated (TAA). The replicas obtained in type V stone were digitalized, and the images were exported to AutoCAD software to perform the readings of possible degree alterations in implant inclinations. The results were submitted to analysis of variance (ANOVA) and Tukey test (α < 0.05). Results: Comparing the techniques with regard to the 90° implant inclination, no statistical difference was observed between the three techniques and the control group. Analyzing the three techniques with regard to the 65° implant inclination, no significant difference was seen between technique TA and the control group. Conclusions: Technique TA presented more accurate master casts than TRS and TAA techniques. The angulated implant (65°) tended to generate more imprecise master casts than implants perpendicular to the surface. © 2008 by The American College of Prosthodontists.

Evaluation of titanium implants with surface modification by laser beam. Biomechanical study in rabbit tibias

The purpose of the present study was to evaluate, using a biomechanical test, the force needed to remove implants with surface modification by laser (Nd:YAG) in comparison with implants with machined surfaces. Twenty-four rabbits received one implant with each surface treatment in the tibia, machined surface (MS) and laser-modified surface (LMS). After 4, 8 and 12 weeks of healing, the removal torque was measured by a torque gauge. The surfaces studied were analyzed according to their topography, chemical composition and roughness. The average removal torque in each period was 23.28, 24.0 and 33.85 Ncm for MS, and 33.0, 39.87 and 54.57 Ncm for LMS, respectively. The difference between the surfaces in all periods of evaluation was statistically significant (p < 0.05). Surface characterization showed that a deep and regular topography was provided by the laser conditioning, with a great quantity of oxygen ions when compared to the MS. The surface micro-topography analysis showed a statistical difference (p < 0.01) between the roughness of the LMS (R a = 1.38 ± 0.23 μm) when compared to that of the MS (R a = 0.33 ± 0.06 μm). Based on these results, it was possible to conclude that the LMS implants' physical-chemical properties increased bone-implant interaction when compared to the MS implants. © 2009 Sociedade Brasileira de Pesquisa Odontológica.

Rehabilitation with zygomatic implants: a treatment option for the atrophic edentulous maxilla--9-year follow-up.

This article reports the 9-year clinical outcome of the two-stage surgical rehabilitation of a severely atrophic edentulous maxilla with a metal-resin fixed denture supported by implants anchored in the zygomatic bone and the maxilla. After clinical and radiographic examination, zygomatic implants were inserted bilaterally and four standard implants were placed in the anterior region of the maxilla. Six months later, the implants were loaded with a provisional acrylic resin denture, and the definitive implant-supported metal-resin fixed denture was provided 1 year after implant placement. After 9 years of follow-up, no painful symptoms, peri-implant inflammation or infection, implant instability, or bone resorption was observed. In the present case, the rehabilitation of severe maxillary atrophy using the zygomatic bone as a site for implant anchorage provided good long-term functional and esthetic results. Therefore, with proper case selection, correct indication, and knowledge of the surgical technique, the use of zygomatic implants associated with standard implants offers advantages in the rehabilitation of severely resorbed maxillae, especially in areas with inadequate bone quality and volume, without needing an additional bone grafting surgery, thereby shortening or avoiding hospital stay and reducing surgical morbidity.

Retention and processing methods of nasal prosthesis

Patients with congenital malformations, traumatic or pathological mutilation and maxillofacial developmental disorders can be restored aesthetically and emotionally by the production and use of facial prostheses. The aim of this study was to review the literature about the retention and processing methods of facial prostheses, and discuss their characteristics. A literature review on Medline (PubMed) database was performed by using the keywords maxillofacial prosthesis, silicone, resin, pigment, cosmetic, prosthetic nose, based on articles published from 1956 to 2010. Several methods of retention, from adhesives to the placement of implants, and different processing methods such as laser, CAD/CAM and rapid prototyping technologies have been reported. There are advantages and disadvantages of each procedure, and none can be classified as better compared to others.

Prosthetic approaches for immediate implants in esthetic areas: Aliterature review and clinical cases

The placement of implants in fresh extraction sockets followed for provisionalization allows soft tissues preservation and alveolar ridge, however for this some requisites are necessary. This article describe the factors involved in immediate implants and the prosthetic approachs for this type of therapy. Addtionaly two clinicals case were presented showing diferents approachs for in prosthetic stage for maintenance the aesthetic aperance of soft tissues of the immediate implants.

Disinfection protocols to prevent cross-contamination between dental offices and prosthetic laboratories

Control of cross-contamination between dental offices and prosthetic laboratories is of utmost importance to maintain the health of patients and dental office staff. The purpose of this study was to evaluate disinfection protocols, considering antimicrobial effectiveness and damage to the structures of prostheses. Solutions of 1% sodium hypochlorite, 2% chlorhexidine digluconate, 50% vinegar and sodium perborate were evaluated. Specimens were contaminated in vitro with standardized suspensions of Candida albicans, Streptococcus mutans, Escherichia coli, Staphylococcus aureus and Bacillus subtilis spores. Disinfection by immersion for 10. min was performed. Final counts of microorganisms were obtained using the plating method. Results were statistically compared by Kruskal-Wallis ANOVA and Dunn's test. The surface roughness of 40 specimens was analyzed before and after 10 disinfection cycles, and results were compared statistically using Student's t test. The solution of 50% vinegar was as effective as 1% sodium hypochlorite and 2% chlorhexidine against C. albicans, E. coli and S. mutans. The sodium perborate solution showed the lowest antimicrobial effectiveness. Superficial roughness increased after cycles in 1% sodium hypochlorite (p=0.02). Solutions of 1% sodium hypochlorite, 2% chlorhexidine and 50% vinegar were effective for the disinfection of heat-polymerized acrylic specimens. Sodium hypochlorite increased the superficial roughness. © 2013 King Saud Bin Abdulaziz University for Health Sciences.

Análise estrutural dos efeitos da desadaptação em componentes de próteses odontológicas utilizando o método dos elementos finitos com elemento de contato e pré-carga

Pós-graduação em Engenharia Mecânica - FEB

Efeito da altura do pilar de diferentes cimentos e das ciclagens térmica e mecânica sobre a resistência máxima á tração de infraestruturas metálicas cimentadas

Pós-graduação em Reabilitação Oral - FOAR

Efeito de tratamento de superfície do titânio comercialmente puro na resistência de união com cimentos ionomérico e resinosos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)