Photoelastic analysis of fixed partial prosthesis crown height and implant length on distribution of stress in two dental implant systems.

The aim of this study was to evaluate by photoelastic analysis stress distribution on short and long implants of two dental implant systems with 2-unit implant-supported fixed partial prostheses of 8 mm and 13 mm heights. Sixteen photoelastic models were divided into 4 groups: I: long implant (5 × 11 mm) (Neodent), II: long implant (5 × 11 mm) (Bicon), III: short implant (5 × 6 mm) (Neodent), and IV: short implants (5 × 6 mm) (Bicon). The models were positioned in a circular polariscope associated with a cell load and static axial (0.

Photoelastic stress analysis of mandibular fixed prostheses supported by 3 dental implants.

Purpose: To observe the photoelastic stress patterns generated around implants in relation to variations in the diameter and total number of implants supporting fixed complete-arch mandibular frameworks.

Materials And Methods: Three different implant configurations were analyzed (n = 3): 5 standard implants with diameters of 3.75 mm (C), 3 standard implants with diameters of 3.

Photoelastic analysis of all-on-four concept using different implants angulations for maxilla.

Conventional tilted implants are used in oral rehabilitation for heavily absorbed maxilla to avoid bone grafts; however, few research studies evaluate the biomechanical behavior when different angulations of the implants are used. The aim of this study was evaluate, trough photoelastic method, two different angulations and length of the cantilever in fixed implant-supported maxillary complete dentures. Two groups were evaluated: G15 (distal tilted implants 15°) and G35 (distal tilted implants 35°) n = 6.

Influence of crown-to-implant ratio on stress around single short-wide implants: a photoelastic stress analysis.

Purpose: The aim of this study was to evaluate the photoelastic fringe patterns around two short-wide implants supporting single crowns with different crown-to-implant (C/I) ratios.

Materials And Methods: External hexagon (EH) cylindrical implants (5 × 7 mm) or Morse Taper (MT) conical implants (5 × 6 mm) were embedded individually into photoelastic resin blocks. Each implant received a single metal-ceramic crown, with a C/I ratio of 1:1 or 2:1 (n = 10).

Prosthetic improvement of pronounced buccally positioned zygomatic implants: a clinical report.

This report presents a prosthetic technique for the improvement of surgically positioned, buccally placed zygomatic implants with the use of custom abutments for improved retention screw position and an esthetic implant reconstruction. The patient presented four zygomatic implants with pronounced buccal inclination. The anterior implants were inclined toward the location where the anterior artificial teeth should be placed during rehabilitation.

Tensile and flexural strength of commercially pure titanium submitted to laser and tungsten inert gas welds.

This study evaluated the tensile and flexural strength of tungsten inert gas (TIG) welds in specimens made of commercially pure titanium (CP Ti) compared with laser welds. Sixty cylindrical specimens (2 mm diameter x 55 mm thick) were randomly assigned to 3 groups for each test (n=10): no welding (control), TIG welding (10 V, 36 A, 8 s) and Nd:YAG laser welding (380 V, 8 ms). The specimens were radiographed and subjected to tensile and flexural strength tests at a crosshead speed of 1.

Stress distribution in Co-Cr implant frameworks after laser or TIG welding.

Lack of passivity has been associated with biomechanical problems in implant-supported prosthesis. The aim of this study was to evaluate the passivity of three techniques to fabricate an implant framework from a Co-Cr alloy by photoelasticity. The model was obtained from a steel die simulating an edentulous mandible with 4 external hexagon analog implants with a standard platform.

Stress evaluation of implant-abutment connections under different loading conditions: a 3D finite element study.

This study evaluated the effects of axial and oblique occlusal loading on implant-supported partial dentures with different connection systems (external hexagon, internal hexagon, and Morse taper). Upon axial loading, all systems presented similar stress values. Stress values increased under oblique loading.

Micro-leakage at the implant-abutment interface with different tightening torques in vitro.

Objectives: This study evaluated the microleakage at the implant/abutment interface of external hexagon (eH) implants and abutments with different amounts of bacteria and tightening torques.

Material And Methods: A bacterial suspension was prepared to inoculate the implants. The first phase of this study used nine EH implants and abutments that were divided into three groups with different amounts of bacterial suspension (n=3): V0.

Influence of methodologic aspects on the results of implant-abutment interface microleakage tests: a critical review of in vitro studies.

Purpose: This study sought to evaluate the influence of methodologic aspects on variations in the findings of in vitro microleakage studies of the implant-abutment interface.

Materials And Methods: The MEDLINE, EMBASE, and Cochrane Library databases were consulted for in vitro studies published between 1990 and August 2011. Date from the studies that met the inclusion and exclusion criteria were arranged in tables and subjected to descriptive analysis.

Photoelastic analysis of the distribution of stress in different systems of overdentures on osseous-integrated implants.

Objective: The aim of this study was to evaluate the distribution of generated stress around implants and adjacent bone tissue using different implant-retained overdenture designs through photoelastic analysis.

Methods: Over an edentulous human mandible, achieved from a human model, 2 or 4 microunit analog abutments were embedded (Master; Conexao Systems Prosthodontics, São Paulo, Brazil), settled in the interforaminal region. Three models of photoelastic resin (Araltec Chemicals Ltda, Hunstman, Guarulhos, São Paulo, Brazil), with 2 or 4 incorporated implants and microunit abutments, were obtained from molds using silicone for duplication.

Fatigue performance of joints executed in pure titanium structures with several diameters.

This study evaluated fatigue strength of CP-Ti laser-welded joints. Sixty (20/diameter) CP-Ti casted dumbbell rods with diameters of 1.5, 2.

Evaluation of anodic behavior of commercially pure titanium in tungsten inert gas and laser welds.

Purpose: This study evaluated the resistance to corrosion in welds made with Tungsten Inert Gas (TIG) in specimens made of commercially pure titanium (cp Ti) in comparison with laser welds.

Materials And Methods: A total of 15 circular specimens (10-mm diameter, 2-mm thick) were fabricated and divided into two groups: control group-cp Ti specimens (n = 5); experimental group-cp Ti specimens welded with TIG (n = 5) and with laser (n = 5). They were polished mechanically, washed with isopropyl alcohol, and dried with a drier.

Radiographic inspection of porosity in Ti-6Al-4V laser-welded joints.

Widely used in dentistry, Ti-6Al-4V alloy is difficult to cast and solder, as it frequently exhibits pores inside the structure. This study was conducted to evaluate the effect of joint openings and diameters of laser-welded joints executed in Ti-6Al-4V structures on the presence of pores as checked by radiographic procedures. Sixty dumbbell rods with central diameters of 1.

Effect of accelerated aging on permanent deformation and tensile bond strength of autopolymerizing soft denture liners.

Purpose: The aim of this study was to evaluate the effect of different accelerated aging times on permanent deformation and tensile bond strength of two soft chairside liners, acrylic resin (T) and silicone (MS) based.

Materials And Methods: Different specimens were made for each test of each reliner. The specimens (n = 10) were submitted to accelerated aging for 2, 4, 8, 16, 32, and 64 cycles.

Radiographic inspection of porosity in pure titanium dumbbell castings.

Background:   Titanium frameworks are frequently indicated for implant supported prostheses; however, voids are usually encountered inside cast titanium.

Objective:   This study aimed to confirm the efficacy of a radiographic technique for inspection of porosity in commercially pure titanium castings with different diameter.

Materials And Methods:   Sixty dumbbell rods (n=20) with a central 1.

Effect of retorque on loosening torque of prosthetic screws under two levels of fit of implant-supported dentures.

This study evaluated the influence of retorque on loosening torque (Lt) of prosthetic screws in implant-supported dentures with different fit levels. Ten mandibular implant-supported dentures were fabricated and then 20 cast models were then prepared using prosthetic structures to create 2 fit levels: passive fit (Pf) and misfit (Mf). Two tightening techniques were also evaluated: initial torque only (T1); and initial torque and retorque after 10 min (T2).

Influence of prosthetic screw material on joint stability in passive and non-passive implant-supported dentures.

Objectives: This study evaluated the influence of prosthetic screw material on joint stability in implantsupported dentures at two levels of fit.

Methods: Ten mandibular implant-supported dentures were fabricated. Twenty cast models were fabricated using these dentures.

Influence of laser-welding and electroerosion on passive fit of implant-supported prosthesis.

This study investigated the influence of laser welding and electroerosion procedure on the passive fit of interim fixed implant-supported titanium frameworks. Twenty frameworks were made from a master model, with five parallel placed implants in the inter foramen region, and cast in commercially pure titanium. The frameworks were divided into 4 groups: 10 samples were tested before (G1) and after (G2) electroerosion application; and another 10 were sectioned into five pieces and laser welded before (G3) and after (G4) electroerosion application.

Influence of simulated microwave disinfection on complete denture base adaptation using different flask closure methods.

Statement Of Problem: Denture microwave disinfection may result in dimensional changes that may distort the acrylic resin base, causing discomfort to the patient.

Purpose: The purpose of this study was to determine the effect of simulated microwave disinfection on maxillary denture base adaptation using 2 different flask closure methods.

Material And Methods: Forty stone cast-wax base sets were prepared for flasking by the traditional flask closure (TFC) and Restriction System flask closure (RSFC) methods (n=20).

Vickers hardness of cast commercially pure titanium and Ti-6Al-4V alloy submitted to heat treatments.

The purpose of this study was to evaluate the effect of heat treatments on the Vickers hardness of commercially pure titanium and Ti-6Al-4V cast alloys. Six-millimeter-diameter cylindrical specimens were cast in a Rematitan System. Commercially pure titanium and Ti-6Al-4V alloy specimens were randomly assigned to 3 groups (n=10) that received the following heat treatments: control (no heat treatment); treatment 1 (T1): heating at 750 degrees C for 2 h; and treatment 2 (T2): annealing at 955 degrees C for 1 h and aging at 620 degrees C for 2 h.

Immediate function in the edentulous mandible: replacement of a lost implant using prefabricated guides.

This article describes a technique for replacement of a lost implant. The procedure involves the use of templates, drill guides, and drills of the system to replace a 4.5-mm-wide lost implant with a 5.

Evaluation of varying amounts of thermal cycling on bond strength and permanent deformation of two resilient denture liners.

Statement Of Problem: Two problems found in prostheses with resilient liners are bond failure to the acrylic resin base and increased permanent deformation due to material aging.

Purpose: This in vitro study evaluated the effect of varying amounts of thermal cycling on bond strength and permanent deformation of 2 resilient denture liners bonded to an acrylic resin base.

Material And Methods: Plasticized acrylic resin (PermaSoft) or silicone (Softliner) resilient lining materials were processed to a heat-polymerized acrylic resin (QC-20).