ABSTRACT
The primary stability of implants should be high on insertion into fresh extraction sockets. Torque-fitting and resonance frequency analyses (RFA) are used to assess primary implant anchorage and stability. The torque-fitting and RFA of implants placed in conventional surgical sockets and sockets with controlled coronal bone defects was compared. The possible relation between torque-fitting and RFA was explored. Ø 3.3 mm x 12 mm implants were placed in 16 sockets finalized with Ø 2.8mm surgical pilot drills in the right iliac crests of two fresh cadavers (control). In the test group, implants were placed into sockets prepared by Ø 2.8mm drill followed by Ø 4.2mm twist drills to a depth of 6mm to create circumferential controlled coronal bone defects (50% bone loss). Primary implant stability was assessed using insertion torque values (ITV) followed by RFA. Mean ITV and RFA measurements for test groups (7.83+/-0.91 N cm and 40.88+/-3.57) were significantly lower than controls (14.80+/-1 N cm and 66.31+/-0.9) (P<0.05). Reductions of ITV and RFA measurements in relation to bone defect were 47% and 38%. The existence of controlled bone defects eliminating contact coronally leads to decrease in torque-fitting and primary stability of implants. No relationship was observed between torque-fitting and RFA.
Subject(s)
Bone Resorption/surgery , Bone and Bones/surgery , Dental Implantation, Endosseous/methods , Dental Implants , Dental Prosthesis Retention , Aged , Bone Density/physiology , Bone Resorption/pathology , Bone and Bones/pathology , Cadaver , Dental Implantation, Endosseous/instrumentation , Humans , Ilium , Male , Osteotomy/instrumentation , Surface Properties , Torque , VibrationABSTRACT
Prudent control of the biomechanical load on dental implants is imperative to achieve long-term clinical success. The design of the final prosthesis and location of force transmission have a definitive influence on the quantification of induced strains and load partitioning among implants. While axial loading of implants generate an even distribution of stresses in the bone around implants, off-set loading, which is particularly observed in screw retained prosthesis increases the stresses at the bone-implant interface. This study evaluated the cervical strains on dental implants supporting four unit cement retained fixed prostheses under 50 N static axial and off-set loading conditions. As the type of strains are also dependent on the point of load transfer, design of the prosthesis and implant positioning, the study comprised the evaluation of induced strains through a simulation of five cement retained prosthetic options. The results revealed that off-set loading increases the magnitude of strains. However, it was not significant for all configurations (P < 0.05). This finding emphasizes the accompanying effect of implant location, angulation and macrogeometry of the prosthesis and, that the biomechanical evaluation of affecting factors is a multifaceted phenomenon.
Subject(s)
Dental Implants , Dental Prosthesis, Implant-Supported , Dental Stress Analysis , Denture, Partial, Fixed , Analysis of Variance , Cementation , Compressive Strength , Dental Prosthesis Retention/methods , Statistics, NonparametricABSTRACT
The clinical and laboratory procedures employed for framework fabrication are inadequate to provide an absolute passive fit for implant-supported fixed superstructures. Although some prosthetic complications are attributed to the lack of passive fit, its effect on implant success is questionable. Nevertheless, the clinical results of increasing applications of advanced technology to improve framework fit seem promising. This article reviews the clinical significance of passive fit and the factors that affect the final fit of implant-supported frameworks.
Subject(s)
Dental Prosthesis Design , Dental Prosthesis Retention , Dental Prosthesis, Implant-Supported , Dental Stress Analysis , Humans , Prosthesis FittingSubject(s)
Aluminum Oxide , Dental Porcelain , Dental Restoration, Permanent , Adult , Dental Restoration, Permanent/methods , Esthetics, Dental , Female , Follow-Up Studies , Humans , Incisor , Maxilla , Time FactorsABSTRACT
Proper placement of implants in the posterior maxillary region with poor bone density is essential to obtain long-term success. In this article, the fabrication of a bilaminar dual-purpose stent that facilitates ease in implant placement with improved verification of implant positioning is described. The outer lamina is designed for use in the computed tomography evaluation, using radiopaque markers. The verification of implant alignment and positioning, according to the determined prosthesis, is also performed with this template after modifying it for surgery. The inner lamina is designed to accept 2 removable surgical acrylic resin stents with different guide channels that avoids the risk of surgical malpractice.
Subject(s)
Dental Implantation, Endosseous/instrumentation , Stents , Technology, Dental , Acrylic Resins , Alginates , Alveolar Bone Loss/diagnostic imaging , Dental Impression Technique , Equipment Design , Humans , Jaw, Edentulous/diagnostic imaging , Patient Care Planning , Tomography, X-Ray ComputedABSTRACT
An implant-supported prosthesis can potentially provide a functional and esthetic reconstruction, provided that the implants are precisely placed in the predetermined location and angulation. Since the accurate placement of osseointegrated implants in the anterior maxilla with questionable bone support is often a clinical challenge, the use of computed tomography and surgical guides is crucial. This article describes a technique to fabricate a template that served as a guide for radiographic evaluation and was then modified for use in the surgical phase of the treatment.
