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Results for “Prosthesis Retention”

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At least 199 records · Page 11Linked to original sources

PubMed2002

One-step implant index verification and maxillomandibular relationship.

Before definitive fabrication of an implant-supported prosthesis, the accurate positioning of the fixtures or abutment replicas on the working master cast must be verified. In addition, the implant master cast must be accurately mounted against the opposing cast. The purpose of this paper is to demonstrate a technique that combines the verification index and a maxillomandibular relationship into one step, with an accurate technique to record the relationship.

Dental Abutments↗

PubMed2002

The three-dimensional finite element analysis of fixed bridge restoration supported by the combination of teeth and osseointegrated implants.

This study investigated the designs of osseointegrated prostheses in cases of free-end partial edentulism using comparative stress interpreted with the three-dimensional finite element method. Three free-end fixed osseointegrated prostheses models with various connection designs (i.e., rigidly connected to an abutment tooth and an implant, rigidly connected to an implant and two abutment teeth, and rigidly connected to an implant and three abutment teeth) were studied. The stress values of the three models loaded with vertical, buccolingual, and linguobuccal directions at 30 degrees angled to vertical axis forces were analyzed. When the fixed partial denture was connected to the three natural abutment teeth and an implant, the lowest levels of stress in the bone were noted.

Alveolar Process↗

PubMed2003

Prosthodontic complications of Spline dental implants.

Access to accurate clinical data on the frequency of prosthodontic complications encountered in dental implant restorations can provide dentists with important information for evaluating dental implant systems. The complication of prosthetic screw loosening, for example, has often been ignored or under-reported. Only limited published clinical data exists on the use of the Spline connections for dental implant restorations. This paper reports on an in-vitro investigation of prosthodontic complications encountered with the Spline dental implant system restored by students and residents at The Ohio State University's School of Dentistry. From a comprehensive list of implant patients generated from the University's computer records, an extensive chart review was conducted, and all patients who were treated with Spline dental implants were entered into the study. During a second chart review, data on all prosthodontic complications with Spline implant restorations were gathered on reporting forms then entered into a computer database and subjected to statistical analysis. The results showed that 95.75% of the prostheses were free of any complications. Iatrogenic factors that resulted in screw loosening were identified. Based on the findings of this relatively short-term study ranging from 29 to 59 months of post-restoration clinical follow-up, Spline dental implants provided a stable implant prosthetic connection.

Adolescent↗

PubMed2004

Screw loosening for standard and wide diameter implants in partially edentulous cases: 3- to 7-year longitudinal data.

Screw loosening is considered to be a common problem with both screw-retained and cemented implant restorations. A wider abutment platform, as well as using a torque driver to tighten specifically designed screws may help prevent this loosening. However, there has been no clinical study evaluating either of these. To longitudinally compare the frequency of screw loosening in standard diameter, (3.75 and 4.0 mm) implant supported prostheses to that of wide diameter, (5.0 and 6.0 mm) implant supported prostheses that were hand tightened, and to evaluate whether using a torque driver would minimize or prevent this problem, if screw loosening occurred. A total of 213 dental implants in 106 patients were included in this prospective longitudinal study. Of the implants 68 were wide diameter and 145 were standard diameter implants. Wide diameter implants showed 5.8% screw loosening, while standard diameter implants showed 14.5% screw loosening after insertion with only hand torquing. When these loose screws were tightened with a torque driver, there was no more loosening of screws. Within the limitations of this study, the wide diameter implants tested showed less screw loosening than the standard diameter implants when hand torqued. Additionally, within the scope of our study, using a torque driver to tighten the screws with the recommended force prevented this loosening from reoccurring in all cases.

Adult↗

PubMed2004

Rationale for the application of immediate load in implant dentistry: Part I.

Immediate loading in implant dentistry is increasing in popularity as a clinical procedure. A scientific rationale of immediate occlusal loading of the implant support system should emphasize methods to decrease surgical trauma during implant placement and to decrease bone loading trauma during the early loading period. The surgical trauma may be reduced by decreasing heat generation and pressure necrosis. The early loading trauma may be decreased by decreasing the bone strain adjacent to the implant interface. Greater microstrain conditions in bone increase the remodeling rate of bone. The higher the remodeling rate, the weaker the bone and the more risk of occlusal overload. Occlusal overload may lead to implant failure. Since strain is directly related to stress, methods to decrease stress are beneficial. In the present report, the stress-reducing influences include increasing the number of implants.

Dental Implantation, Endosseous↗

PubMed2004

Cementable implant-supported prosthesis, serial extraction, and serial implant installation: case report.

Cement-retained implant-supported prostheses are particularly indicated where access for screw placement is limited or impossible like in posterior locations or where there is limited jaw opening. The patient in this case report suffered from limited jaw opening as a result of a long history of temporomandibular joint ankylosis related to hemophilia. Cement-retained implant-supported prostheses coupled with serial extraction, serial implant installations, and chairside provisional restorations made uneventful treatment possible.

Ankylosis↗

PubMed2004

Private practice results of dental implants. Part I: survival and evaluation of risk factors--Part II: surgical and prosthetic complications.

The aim of this study is to present the clinical data from the use of implants that were placed and restored in four independent private dental offices. In part I, the survival rate was calculated and the failure causes were associated with some potential risk factors. In part II, the surgical and prosthetic complications were also recorded and associated both with failures and clinical factors. During 1990-2002 (mean observation 4.6 years), 1692 dental implants were placed and restored in 405 patients in 4 private clinics following the same treatment protocol. The prosthetic restorations included fixed partial dentures, single crowns, and overdentures. The results were statistically analyzed and survival rate probability curves were calculated according to Kaplan-Meier analysis. Part I: Seventy-four implants (4.4%) in a total of 1692 implants failed. The mean of time elapsed before removal of the failed implants was 40 months. The failure rate was higher in the maxilla in patients with metabolic diseases, in D4 bone quality, in smokers, and in patients with insufficient oral hygiene. Part II: Surgical complications happened to 65 implants (3.8%). Prosthetic complications appeared in 152 implants (9%). The overall survival rate (95.6%) in a period of 1 to 12 years is comparable to other studies. The early failures represented a high percentage of failures. Peri-implantitis was the main cause of late failures. The results of this study indicate that the use of implants in private clinics is a safe and predictable method for the treatment of partially or completely edentulous patients, if the proper clinical protocol is followed. The need of a severe recall program must also be emphasized.

Adolescent↗

PubMed2006

Passive definitive fit of bar-supported implant overdentures.

A passive fit is an important prerequisite for implant-supported prostheses. It limits the amount of stress transferred to the bone-implant interface and ensures long-term osseointegration. A simplified technique is proposed for the fabrication of passive bar-supported implant overdentures. The use of titanium industrial components enhances the precision of fit, and the passivity is achieved with an intraoral luting sequence and laser welding. The method is quick and standardized, and does not require sophisticated steps. This article shows the results of 7 cases 18-24 months (mean 21.4) after the loading of cases.

Aged↗

PubMed1995

Cross-sectional design and fatigue durability of cantilevered sections of fixed implant-supported prostheses.

PURPOSE: Characterizing the fatigue behavior of cantilevered implant-supported prostheses requires an understanding of both the material and its intended application. The relationships between applied load, component geometry, and the fatigue characteristics of a specific material often can be difficult to establish. Four different cross-sectional designs of cantilevered frameworks used clinically were tested for fatigue durability, and the results were compared with theoretical tip deflections and stresses. MATERIALS AND METHODS: Fatigue tests were conducted on specimens with I-, U-, and L-shaped and elliptical cross-sections after static stress analysis. Specimens with uniform cantilevered length were sprued, invested and cast from the same high-palladium alloy. Statistical results, SEM evaluation of fracture surfaces, and theoretical predictions provided further insight into the framework design. RESULTS: Based on intraoral space restrictions, corrections for dimensional changes inherent in casting, the mean number of cycles to failure for each cross-sectional geometry, and the performance of design groups as predicted by static analysis can be ranked in order from best to worst as I, L, U, and then elliptical. SEM evaluation showed varying degrees of porosity and shrinkage cavities specific to the specimen cross-sections. CONCLUSIONS: Four designs for the cantilevered sections of implant-supported frameworks were evaluated for fatigue durability and were compared with the results of the theoretical analysis. As tested, fatigue durability was predictable when compared with theoretical calculations of tip deflection and normal stress. Although all four shapes have considerable merit for rigidity, in limited intermaxillary conditions, the I- and L-shaped cross-sections may optimize performance and use of space.

Chi-Square Distribution↗

PubMed1995

Comparison of strains transferred to a bone simulant among implant overdenture bars with various levels of misfit.

PURPOSE: To measure and compare strains transferred to a bone simulant by screw-fastening implant overdenture bars with various levels of fit or misfit. MATERIALS AND METHODS: Photoelastic resin was cast directly to two 3.75 X 13-mm Branemark fixtures (Nobelpharma USA Inc, Chicago, IL) situated 20 mm apart in a silicone mold of an edentulous mandible. Two strain-gauge rosettes were also incorporated in the resin to allow precise determination of principal stresses at two locations. Four groups of three overdenture bars with 0-, 180-, 360-, and 500-micrometer vertical gaps were fabricated. These bars were sequentially secured to the abutments with gold slot screws tightened to 10 N-cm. Strain indicator readings were recorded at a standardized time following the initial fastening of each bar. The test was repeated three times for each overdenture bar. RESULTS: Mean principal stresses and strains at the location of the rosettes were determined. The magnitude of these stresses and strains increased significantly with each increase in gap size. Strains were several times larger mesial to the fixture than they were distal. CONCLUSIONS: Strains are transferred to the bone when misfitting prostheses were secured. Some of the strains mesial to the fixture appeared to be unfavorable for regions of lower bone density when the groups with designed gaps were secured. These data will be compared with those in ongoing animal studies regarding the cellular response to prosthesis misfit.

Alveolar Process↗

PubMed1996

Prosthodontic management of a combination transosteal/endosteal implant reconstruction: a clinical report.

This is a clinical report of a patient who was not referred for prosthodontic evaluation and treatment until after undergoing Bränemark endosseous implant placement to supplement the previously existing mandibular staple bone plate implant. This supplemental treatment was the surgeon's attempt to resolve the patient's complaint of loose dentures. Creativity with implant biomechanics and prosthodontic design were necessary to restore the patient, in a predictable manner, to normal function. A fixed, detachable cast overdenture bar rigidly connected to all the implants was constructed utilizing resilient attachments to retain the tissue-supported mandibular overdenture. A presurgical prosthodontic evaluation could have averted many of the problems encountered with treatment. More effective conventional prosthodontic treatment may have resolved the patient's complaints and eliminated the need for additional implant placement.

Bone Plates↗

PubMed1996

Multiple implants for first molar prosthodontics.

Problems that can occur when single implants are utilized to restore first molar teeth include the frequent loosening of screws, as well as screws and/or implant breakage. These may result from torquing and rotational movements of the prosthesis during masticatory and parafunctional mandibular movements. When sufficient bone and mesio-distal restorative space is present, the placement of two implants should be considered.

Dental Abutments↗

PubMed1996

Comparison of strains transferred to a bone simulant between as-cast and postsoldered implant frameworks for a five-implant-supported fixed prosthesis.

PURPOSE: To measure and compare the strains transferred by screw-fastening one-piece full-arch prostheses as cast and after sectioning and soldering. MATERIALS AND METHODS: Photoelastic resin was applied directly to five 3.75 x 13-mm Brånemark implants, situated 7 mm apart, in a silicone mold of an edentulous mandible. Four strain gauge rosettes were also incorporated in the resin to allow strain measurements at four locations. Three frameworks were made from a single master cast produced from an impression of the five-implant model with 4-mm abutments. These frameworks were sequentially secured to the master model with five gold slot screws tightened to 10 N cm. Strain indicator readings were recorded at a standardized time following the initial fastening of each prosthesis. The test was repeated three times. Each of the three castings were subsequently sectioned and soldered in two locations, mesial to the two terminal fixtures. After soldering, the three superstructures were returned to the master model for measurement of postsolder strains three times each. A one-way repeated-measures ANOVA was performed to determine differences between mean principal strains between the as-cast and postsoldered groups. RESULTS: A statistically significant difference was found in the principal strains between the as-cast and soldered frameworks. Overall, there was a decrease in the magnitude of strain for the soldered frameworks. CONCLUSIONS: Sectioning and soldering improved the as-cast accuracy as far as the amount of strain transferred to the bone simulant.

Alveolar Process↗

PubMed1996

The Periotest method: implant-supported framework precision of fit evaluation.

PURPOSE: In this study, the Periotest instrument was used to measure the precision of fit between cast high noble-metal frameworks and the supporting implants in a patient-simulation model. Three framework conditions and three implant-location variables were used to evaluate the rigidity of the assembly as measured by the Periotest method. The framework variables were (1) one-piece castings (OPC); (2) sectioned-soldered inaccurate castings (SSIC); and (3) sectioned-soldered accurate castings (SSAC). The implant-location variables were right anterior (RA), center (C), and left anterior (LA). MATERIALS AND METHODS: The patient simulation model used consisted of three self-tapping Branemark implants in a reasonable arch curvature in bovine bone. Three working casts were fabricated from the patient-simulation model using polyvinyl siloxane and tapered impression copings. From the working casts, three sets of three frameworks were fabricated as OPCs, SSICs, and SSACs using type 3 high noble alloy. The SSICs were fabricated with a quantitative misfit of 101.6 microns at the facial surface, between the abutment-to-gold cylinder interface at the C implant location. Periotest value (PTV) measurements were made at the midfacial surface of the frameworks directly above each abutment-to-gold cylinder interface. Three measurements were made for each test condition. The data were analyzed to compare framework condition(s) and implant location(s) using ANOVA and Fisher's Protected Least Significant Difference Comparison Test. RESULTS: The ANOVA showed that significant differences exist between the mean PTV data for framework condition and for implant location (p < .01). Significant differences were shown between the mean PTV data for the SSAC assemblies and the OPC and SSIC assemblies. The SSICs displayed a more positive (+) mean PTV than the OPCs. The OPC assemblies had a more positive mean PTV than the SSAC assemblies. The mean PTV data for the SSAC assemblies had a significantly different PTV (p < .01) than the other two framework condition assemblies. The OPC and the SSIC assemblies had PTVs that were not significantly different. The C implant location was significantly different from the RA and the LA implant locations (p < .01). The RA and the LA implant locations were not significantly different from each other. The C implant location always demonstrated the most positive mean PTV regardless of the framework condition being tested. CONCLUSIONS: The Periotest instrument quantified differences in the precision of fit between three framework conditions. The SSAC assemblies were significantly more rigid than the OPC and SSIC assemblies. The OPC and SSIC assemblies' mean PTVs were not significantly different. The mean PTVs for the C implant location and the RA and LA implant locations were significantly different (p < .01). The mean PTVs of the RA and LA implant locations were not significantly different. The implant-location PTVs followed the same rank order for all three framework conditions. The procedures used to fabricate a more precise fit between the framework and the supporting implants is influenced by the skill of the clinician and technician.

Analysis of Variance↗

PubMed1996

Controlled retainer-screw access placement for screw-retained implant prosthesis.

An implant-supported prosthesis is often secured to the underlying gold cylinders by retaining screws. There must be access to these screws from the oral surface of the prosthesis. Conventional preparation of this access is from the oral surface. This approach is difficult because the underlying gold cylinder is obscured. It may be damaged by a rotary cutting instrument as the access is prepared above it, because the cylinder cannot be seen during the preparation. Alternatively, the access hole may be unnecessarily enlarged in an attempt to find the cylinder. This loss of structure may weaken the prosthesis. A new approach, using 18-gauge stainless steel wire as a rotary cutting instrument, permits preparation of the access chamber from the intaglio surface of the prosthesis. This reduces risk of damage to the gold cylinder and is less destructive to the overlying material.

Bone Screws↗

PubMed1998

An alternative to splinting multiple implants: use of the ITI system.

The restoration of patients with dental implants presents many challenges. Some of the common concerns and problems are difficulty in achieving a passive-fitting cast framework and loosening of prosthesis-retraining screws or abutment screws when using external hex prosthesis connection systems. The ITI system uses a unique connection of the abutment to the prosthesis-anchoring component. Because of this unique connection, many problems encountered with external hex designs have been greatly reduced or eliminated by the ability to more easily restore individual teeth with individual implants. This article will present the rationale for restoration of a patient with implants using individual implant-supported restorations.

Dental Abutments↗

PubMed1999

A soldering index for cement-retained implant restorations.

Recent advances in implant abutment interface design purport to offer more repeatable, accurate abutment connection. Improved circumferential indexing of the abutments along with a decrease in micromovement may result in a more predictable fit of cement-retained implant prostheses through a simple variation of soldering technique. A technique for developing a more accurate soldering relationship is described.

Cementation↗

PubMedDate not supplied

Immediate occlusal loading of Osseotite implants in mandibular edentulous patients: a prospective observational report with 18-month data.

PURPOSE: To evaluate the efficacy of treatment consisting of placement and immediate occlusal loading of implants in 27 patients with edentulous mandibles. MATERIALS AND METHODS: Twenty-seven patients were treated in two private practice settings. One hundred fifty-one implants were placed and immediately occlusally loaded with fixed implant prostheses (15 cement-retained, 12 screw-retained) on the day of implant placement. The implant-retained prostheses were inserted within 5 hours of implant placement. Patients were followed for at least 18 months. The required criteria for immediate occlusal loading was primary implant stability of at least 30 Ncm of insertion torque. The implant prostheses were removed at least 12 months post-placement and the implants were evaluated for primary clinical stability and radiographic bone apposition to implants. RESULTS: At the 12-month follow-up appointments, cumulative survival rates of 98.0% and 100% were recorded for implants and prostheses, respectively. Three implants failed within 3 months. All other implants were clinically successful. CONCLUSIONS: Immediate occlusal loading of multiple, splinted mandibular implants is an effective treatment when implants are stable at insertion and are rigidly splinted with implant-retained prostheses.

Adult↗