Prostheses may be attached to implants or implant abutments using screw retention or cementation. With the increased use of cement-retained, implant-supported restorations for the replacement of missing teeth, clinicians may choose to use a definitive cement to lute the definitive restoration. Loosening of an abutment ...

The goal of this prospective clinical study is to evaluate a new all-ceramic implant abutment made from zirconium oxide during the immediate load of dental implants placed in the block grafted anterior maxilla. This new zirconia abutment gives the clinician the opportunity to provide the patient with an all-ceramic restorative system ...

Maintenance of the integrity of the abutment/implant interface is essential and is dependent on the abutment screw retaining a preload. Evaluation of this joint is usually done by manual assessment. The purpose of the current study was to determine whether the Periotest instrument could be used to evaluate abutment ...

The aim of this in vitro study using implants and abutments was to examine traces left by various cleaning instruments and to determine the quantity of substance removal. The implants and relevant abutments were Screw-Vent implants (Dentsply), titanium plasma-coated full-screw implants ...

Abstract Dental implants can be rendered useless due to complications related to implant components such as the fracture of abutment screw and prosthetic retaining screw. Removal of such fractured fragments is therefore deemed necessary for the sake of prosthetic restoration. This case report presents a rare incident of healing ...

A technique to create an individually modified implant prosthetic abutment is described. An overcasting is waxed onto a machined titanium abutment, cast in titanium, and joined to it with laser welding. With the proposed technique, a custom-made titanium implant prosthetic abutment is created with adequate volume and contour of metal ...

Abstract The aim of this technique report was to present a procedure for removal of a fractured implant abutment screw. Whatever the cause, when an abutment fracture has occurred, the fractured screw segment inside the implant must be removed. The methods used by the clinicians may include the use of an ...

This study investigated whether there is a direct correlation between the level of vertical misfit at the abutment/implant interface and torque losses (detorque) in abutment screws. A work model was obtained from a metal matrix with five 3.75 x 9 mm external hex implants with standard platform (4.1 mm). Four frameworks were waxed using ...

Objectives: The aim of this study was to evaluate the variation in removal torque of implant prosthetic abutment screws after successive tightening and loosening cycles, in addition to evaluating the influence of the hexagon at the abutment base on screw removal torque. Material and methods: Twenty hexagonal ...

Concerns have been raised about the degradation of hydroxyapatite (HA) coatings on dental implants over time. It has been speculated that the resorption of HA could produce a space between implant and bone, resulting in mechanical instability and implant failure. A screw-shaped HA-coated implant was retrieved after the ...

S>Metal jacketed metallic bodies of the type used as feel elements fer nuclear reactors are presented. The fuel element is comprised of a plurality of jacketed cylindrical bodies joined in end to end abutting relationship. The abutting ends of the internal fissionable bodies are provided with a mating screw and thread ...

A device for manufacturing containers for storing nuclear materials. The purpose of the device is to maintain angular sheet metals in the precise position required during the welding operation which is performed along the outer edges of their flange portions. The device includes a core, a thrust bearing and a counter-pressure bearing. The core is sub-divided into two separate core portions. Spring ...

Purpose: Conical implant-abutment connections for platform switching have been recently introduced in implant systems. This study investigated the load fatigue performance of three conical abutment systems and their corresponding titanium and zirconia abutments. Materials and Methods: Regular-diameter implants of the Ankylos (AK), ...

Abstract Statement of problem: When a cylinder is connected to an abutment it is expected that abutment and cylinder will be subjected to compression forces throughout their periphery because of the clamping force exerted by the screw. The deformation resultant of this compression should be measurable and uniform along the periphery of ...

In the plant for collecting and briquetting domestic waste the housing has loading and discharge openings and coaxially accommodates therein a chamber for forming domestic waste into briquettes and a conveyer screw for compacting the domestic waste , operatively connected to a reversible drive. The chamber adjoins the screw and has mounted therein an ...

Computer-aided design/computer-aided manufacturing (CAD/CAM) custom abutments have been attracting more and more attention due to their advantages of accuracy fit and esthetic emergence profile. However, the CAD key technology for custom abutments has been seldom studied as well as their biomechanical behavior. This paper explored a novel method to design ...

Aim: Settling (embedment relaxation), which is the main cause for screw loosening, is developed by microroughness between implant and abutment metal surface. The objective of this study was to evaluate and compare the relationship between the level of applied torque and the settling of abutments into implants in external and internal ...

The purpose of this study was to develop a technique to evaluate the implant-abutment gap of an external hexagon implant system as a function of radius. Six implants of 3.75 mm in diameter (Conexao Sistema de Protese Ltda, Sao Paulo, Brazil) and their respective abutments were screw connected and torqued to 20 N cm(-1). The implants ...

The aim of this study was to compare and evaluate strain distribution on dental implant, abutment, screw and crown virtual models in the posterior region. The analysis was performed by means of a 3D virtual model developed by the PRO-ENGINEER System (PRO-ENGINEER, PTC, Needham, MA, USA ) with an external butt joint (3i Implant Innovations, Palm Beach, ...

This document discloses an optical element support capable of pivoting an optical element on its horizontal and vertical axes. The pivoting adjustments are facilitated by spaced threaded rods screwed into a support element and abutting a surface element e...

Screw retention for single-tooth restorations on dental implants is often advantageous, as it facilitates crown removal should an adverse event occur, or if modifications to the prosthesis design are anticipated. Prosthetic alterations can be problematic, however, if the screw access hole is not optimally placed to allow clinical access without ...

We describe a case of percutaneous placement of a thoracic aortic stent-graft for safe removal of a malpositioned pedicle screw in a 52-year-old man. The patient had undergone posterior thoracic spinal instrumentation for pyogenic spondylitis and spinal deformity 8 months previously. Follow-up CT images showed a malpositioned pedicle screw which was ...

We describe a case of percutaneous placement of a thoracic aortic stent-graft for safe removal of a malpositioned pedicle screw in a 52-year-old man. The patient had undergone posterior thoracic spinal instrumentation for pyogenic spondylitis and spinal deformity 8 months previously. Follow-up CT images showed a malpositioned pedicle screw which was ...

The strength and mode of failure of three different designs of custom-made all-ceramic implant abutments fabricated by milling of In-Ceram sintered ceramic blocks were compared with the conventional CeraOne system under static load. Four test groups were formed with different locations of abutment screws. In three test groups, In-Ceram ...

The passive fit between prosthesis and implant is a relevant factor for screw joint stability and treatment success. The aim of this study was to evaluate the influence of vertical misfit in abutment-implant interface on preload maintenance of retention screw of implant-supported crowns. The crowns were fabricated with different ...

The passive fit between prosthesis and implant is a relevant factor for screw joint stability and treatment success. The aim of this study was to evaluate the influence of vertical misfit in abutment-implant interface on preload maintenance of retention screw of implant-supported crowns. The crowns were fabricated with different ...

Functional rehabilitation of edentulous jaws using a CAD/CAM-guided implant protocol is commonly recommended as a definitive treatment modality. A patient with an edentulous maxilla received 7 endosseous implants using a CAD/CAM surgical template. A provisional maxillary acrylic resin fixed complete denture was connected immediately after implant placement using a combination of ...

Abstract Statement of problem: Excessive heat generated at the implant-bone surface may result in bone damage and consequently compromise osseointegration. Autopolymerizing acrylic resins are commonly used intraorally to fabricate restorations. The purpose of this in-vitro study was to evaluate the effects of heat generation at implant surface due to exothermic setting reaction of autopolymerizing ...

STATEMENT OF PROBLEMUnlike screw-retention type, fixture-abutment retention in Locking taper connection depends on frictional force so it has possibility of abutment to sink.PURPOSEIn this study, Bicon� Implant System, one of the conical internal connection implant system, was used with applying loading force to the ...

... Case-hardened worms and worm mechanisms do not ... 1) as on the steel ball screws ... elastic and homogeneous bodies, isotropic materials, smooth ...

The electrodeposited cadmium coating used to prevent corrosion of screws can cause hydrogen embrittlement type failures. Protective coatings applied to screws by processes other than electrodeposition were tested for corrosion resistance (5% salt spray te...

BackgroundMost dental implant systems are presently made of two pieces: the implant itself and the abutment. The connection tightness between those two pieces is a key point to prevent bacterial proliferation, tissue inflammation and bone loss. The leak has been previously estimated by microbial, color tracer and endotoxin percolation.MethodsA new nitrogen flow technique was ...

Background: Polyetheretherketone (PEEK) temporary abutments have been recently introduced for making implant-supported provisional single crowns. Little information is available in the dental literature on the durability of provisional implant-supported restorations. Purpose: The objectives of this study were to evaluate the fracture strength of implant-supported composite ...

The formation of bacterial biofilm on the surface of implanted metal objects is a major clinical problem. The antibacterial and antifungal effect of silver ions has been long known, and seems to give silver the capability to inhibit biofilm formation. To test the effect of silver ions, 20 New Zealand rabbits had bacteria applied to a screw insertion site at the iliac crest, ...

Abstract The aim of the present research is an in vitro evaluation of the preload distribution in screw retained implant system under cyclic load. Materials and method. Cyclic loading. In the present research two implant systems with internal connection have been tested: fifteen 4.5x10 mm implants with internal hexagon and fifteen 4.5x10 mm implants with internal octagon. ...

Abstract Passive fit of a long span screw-retained implant prosthesis is an important criteria for the success of the restoration. This article describes a technique for the fabrication of a ceramo-metal implant fixed dental prosthesis (FDP) for a long span partially edentulous situation by alteration of the conventional screw-retained design. The ...

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 ...

Freitas AC Jr, Bonfante EA, Rocha EP, Silva NRFA, Marotta L, Coelho PG. Effect of implant connection and restoration design (screwed vs. cemented) in reliability and failure modes of anterior crowns. Eur J Oral Sci 2011; 119: 323-330. � 2011 Eur J Oral Sci The mechanical performance of cemented or screw-retained implant-supported crowns with an internal ...

This study evaluated the loss of the torque applied after use of new screws and after successive tightening. Four infrastructures (IE), using UCLA castable abutment type, were cast in cobalt-chromium alloy and new abutment screws (G1) were used in a first moment. Subsequently, the same abutment ...

... Protective coatings applied to screws by processes other than electrodeposition were tested for corrosion resistance (5% salt spray test). ...

Abutment manipulation, namely repeated screwing and unscrewing may have an affect on the final marginal bone level, consequently, soft tissue position around endosseous implants. In order to maintain the crestal bone level constant and avoid the apical recession of gingiva final abutment (Direct Abutment, Astra ...

Background:The aim of research was to study spiral family implant by finite element analysis (FEA) inserted in different bone qualities connected with abutments of different angulations.Methods:The biomechanical behaviour of 4.2 � 13 mm dental implants, connecting screw, straight and 15� and 25� angulated abutments subjected to ...

Abstract Purpose: The stability of the bone-implant interface is required for the long-term favorable clinical outcome of the implant supported prosthetic rehabilitation. The implant failures that occur after the functional loading are mainly related to biomechanical factors. Micro movements and vibrations due to occlusal forces can lead to mechanical complications such as loosening of the ...

Cases demonstrating complications in osseointegrated implant supported prostheses are described. These complications occurred in the prostheses framework or veneer, in the fixation screw, in the abutment post or screw as well as in the implant body. The two main reasons for the complications were lack of passive fitting between the ...

Screw-retained implant crowns may be clinically demanding, especially managing the esthetic and occlusal challenges of screw access channel closure. Many clinicians have moved away from using screw retention as a means of fixing a crown to an implant in favor of cementation to an underlying abutment. A link has ...

Preload loss can favor the occurrence of implant-abutment interface misfit, and bacterial colonization at this interface may lead to implant failure. The aim of this study was to evaluate the preload loss and bacterial penetration through the implant-abutment interface of conical and external hexagon connection systems subjected to thermal cycling and ...

Objective:To investigate microbiological biofilm contamination of retrieved bone-anchored hearing aids.Materials and methods:Nine failed, retrieved bone-anchored hearing aids and 16 internal screws were examined by scanning electron microscopy. A fixture from a failing implant, which had been removed and disassembled under aseptic conditions, was cultured. Finally, an internal ...

The purpose of this in vitro study was to evaluate the fracture resistance of single-tooth implant-supported all-ceramic restorations, composed of zirconium dioxide all ceramic restorations on different implant abutments, and to identify the weakest component of the restorative system. Forty-eight standardized maxillary central incisor zirconia crowns (Procera) were fabricated ...

Background: Two-piece implants present gaps and cavities between the implant and the abutment, and these hollow spaces can act as a trap for bacteria. Aim of the present in vitro study was to evaluate the migration of two different microbial species from the inside to the outside of the implant-abutment assembly in three different types of connection. ...

Although many improvements have been made to implant dentistry during the last quarter of a century, clinical challenges still remain. For the surgeon, achieving implant stability in low-density bone can be difficult. For the restorative dentist, incompatibility between implant systems and the increasing complexity of esthetic restorative options frequently require special training in the ...

We measured the insertion and extraction torque forces in a randomised study of 76 external fixation screws in 19 patients treated by hemicallotasis for osteoarthritis of the medial side of the knee. The patients were randomised to have either standard tapered screws (Orthofix 6/5 mm) or the same screws with hydroxyapatite (HA) ...

Stainless steel screws and other internal fixation devices are used routinely to stabilize bacteria-contaminated bone fractures from multiple injury mechanisms. In this preliminary study, we hypothesize that a chitosan coating either unloaded or loaded with an antibiotic, gentamicin, could lessen or prevent these devices from becoming an initial nidus for ...

Titanium and its alloys are widely used in prosthetic dentistry, due to their biocompatibility, excellent mechanical and anti-corrosion behavior. However, delayed fracture of dental prosthetics is frequently encountered. Mechanisms leading to fracture are not generic but are strongly related to the particular environmental (quality of biological fluids) and mechanical loading conditions ...

Purpose: To investigate the effects of internally connected engaging component position in screw-retained fixed cantilevered prostheses. Materials and Methods: Twenty-one three-unit fixed dental prostheses (FDPs) were cast in high-palladium alloy in three groups. In group A, engaging components were incorporated into the units away from the cantilevered segment; proximal units ...

Background: Although increase of misfit has been reported when associating implant and abutment from different manufacturers, Procera custom abutment has been universally used in clinical practice. Purpose: The purpose of this investigation was to compare the vertical gap of zirconia Procera� abutment associated with implants from ...

Background: Although increase of misfit has been reported when associating implant and abutment from different manufacturers, Procera� (Nobel Biocare�, G�teborg, Sweden) custom abutment has been universally used in clinical practice. Purpose: The purpose of this investigation was to compare the vertical gap of zirconia Procera ...

In the ceramic industry, the materials and additives used in the extrusion process result in heavy wear on the screws and barrels. To counteract this effect, it is crucial that the processing units are designed to provide an economically acceptable working life. The screws should also be able to be re-coated i.e. used several times to ...

The paper reports on results of technological research on the coating of standard screw taps with TiN layers deposited by means of arc-plasma discharges, which were carried out within a BULAT-type device equipped with three identical metal-plasma sources. Particular attention is paid to morphology of the coated surfaces. Some data ...

A method of using osseointegrated implants as an alternative treatment modality for transverse root fractures near the osseous crest is presented. A 15-mm Branemark implant was placed immediately after extraction of a maxillary central incisor with transverse root fracture. Five months after stage I surgery, the implant was uncovered. Custom fabrication of a substructure core cast directly to the ...

This clinical report describes 2 patient situations in which fractures related to occlusal overload occurred with a single posterior implants. The initial clinical presentation of both patients appeared to be screw loosening, but upon further examination, implant and abutment fractures were identified. Several factors are described that have been ...

Surgical guides have evolved to the point that they can be created with the aid of computer-assisted tomography (CT) technology. Surgical guides also are used in construction of the prosthesis prior to implant surgery. With existing guide techniques, the prosthesis is screw retained, or cone-shaped temporary abutments may be used to overcome the lack of ...

Using computed tomography, the volume, location, and number of osteolytic lesions were determined adjacent to 38 Harris-Galante 1 (HG-1) acetabular components fixed with screws and 19 porous-coated anatomic (PCA) acetabular components press-fitted without screws. The median implantation times were 16 and 15 years, respectively. The ...

2. Electrode construction showing the nichrome coating, placement of the copper wires, conducting and polished to optical flatness. On one side (the back) of one blank, which will be the bottom electrode the nichrome coating, placement of the copper wires, conducting paint, and one of the three screw clamp holes

The durability of screw and cylinder of thermoplastic machines processing glass reinforced resins such as polyamides at temperatures of the order of 300C is studied. The behavior of protective coatings including metallic coatings such as treated superallo...

Abstract Implant-supported restorations can be secured to implants with screws (screw-retained) or can be cemented to abutments which are attached to implants with screws (cement-retained). This literature review discusses the advantages and disadvantages of each method of retention from different aspects. These ...

The aim of this study was to evaluate the stress distribution of platform switching implants using a photoelastic method. Three models were constructed of the photoelastic resin PL-2, with a single implant and a screw-retained implant-supported prosthesis. These models were Model A, platform 5.0 mm/abutment 4.1 mm; Model B, platform 4.1 ...

Purpose: The aim of this study was to evaluate the effect of mechanical cycling and different misfit levels on Vicker's microhardness of retention screws for single implant-supported prostheses. Materials and Methods: Premachined UCLA abutments were cast with cobalt-chromium alloy to obtain 48 crowns divided into four groups (n = 12). The crowns presented ...

The use of fiber composite technology in the creation of metal-free implant prostheses may solve many of the problems associated with a metal alloy substructure such as corrosion, toxicity, complexity of fabrication, high cost, and esthetic limitations. Laboratory and clinical research evaluating glass fiber-reinforced composite prostheses used to restore and replace teeth has shown that these ...

Biologic and technical complications are widely reported in the dental literature and often compromise the functional and/or aesthetic features of fixed, implant-supported prostheses. Managing complications without damaging or destroying a restoration is an obvious advantage of implant-based dentistry where the option of prosthetic retrievability is almost always available. The technique of ...

We investigate the anchorage of pedicle screws with different surface treatments in osteoporotic bone. Eight ewes were divided into two groups of four animals each: four sheep underwent bilateral ovariectomy (OVX Group), whereas the operation was simulated in the remaining group (SHAM Group). Eighteen months after the first operation, the Dynesys(�) System was fitted to the ...

When stabilising a fracture the contact between the screw and the surrounding bone is crucial for mechanical strength. Through development of screws with new thread designs, as well as optimisation of other properties, improved screw purchase has been gained. Other alternatives to improve screw fixation in ...

The design and retentive properties of implant-abutment connectors affect the mechanical resistance of implants. A number of studies have been carried out to compare the efficacy of connecting mechanisms between abutment and fixture. OBJECTIVES: The aims of this study were: 1) to compare 3 implant-abutment interfaces (external hexagon, ...

This in vitro study investigated the fracture behaviour of implant-implant-supported and implant-tooth-supported all-ceramic fixed dental prostheses (FDP) using zirconium dioxide implant abutments (FRIADENT� CERCON� abutments, DENTSPLY Friadent). Six different test groups (n?=?8) were prepared. Groups 1, 2, 4, and 5 represented an ...

Applying bioactive coatings on orthopedic implants can increase the fixation and long-term implant survival. In our study, we compared a resorbable electrochemically deposited calcium phosphate coating (Bonit(�) ) to a thin (40 ?m) plasma-sprayed hydroxyapatite (HA) coating, applied on grit-blasted screw-shaped ...