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Results for “Prosthesis Retention”

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At least 1,225 records · Page 68Linked to original sources
PubMed2003

[The measurement and comparison of shear fracture strength and shear bond strength between carbon fiber post and some other posts].

OBJECTIVE: The shear fracture strengths of carbon fiber post, IPS-Empress 2 all-ceramic post (without ZrO2 post), cast Ni-Cr alloy post, prefabricated zirconia ceramic post, human dentin and the shear bonding strengths of the first three kinds of post bonded in the human root canals were measured and compared, which are as the reference for dental clinic. METHODS: Standard cylindrical samples were made respectively in each group of carbon fiber post, IPS-Empress 2 all-ceramic post, cast Ni-Cr alloy post, prefabricated zirconia ceramic post, human dentin, three for each group. The shear fracture strengths of these samples were measured by universal testing machine (AUTOGRAPH DCS5000). Standard cylindrical samples were made respectively in each group of carbon fiber post, IPS-Empress 2 all-ceramic post (without ZrO2 post), cast Ni-Cr alloy post, five for each group. They were bonded in extracted human root canals that had been prepared to 3.0 mm length and 2.0 mm diameter with Glass ionomer cement (Japan Shofu). The shear bond strengths were measured by the same universal testing machine. RESULTS: The shear fracture strengths of the carbon fiber post (199MPa), cast Ni-Cr alloy post (210MPa, shear bend strength) and prefabricated zirconia ceramic post (193MPa) were statistically higher than those of IPS-Empress 2 all-ceramic post (109MPa) and human dentin (100MPa). The shear fracture strength of the carbon fiber post was statistically similar to that of cast Ni-Cr alloy post and prefabricated zirconia ceramic post. There were no statistical differences between the shear bond strengths of carbon fiber post (2.4MPa) and cast Ni-Cr alloy post (3.8MPa). IPS-Empress 2 all-ceramic post broke before debonding (2.7, break value). CONCLUSIONS: Carbon fiber post, as well as cast Ni-Cr alloy post and prefabricated zirconia ceramic post, has a comparatively high shear fracture strength. The shear bond strengths of carbon fiber post is similar to cast Ni-Cr alloy post.

Carbon↗
PubMed2003

[The apply of Cosmopost ceramic posts in clinic].

OBJECTIVE: To investigate the manufacture method and the effects of Cosmopost ceramic posts, to summarize the indications of Cosmopost ceramic post in clinic. METHODS: 228 pieces Cosmopost ceramic posts and cores were made for 96 patients. 2l7 pieces full ceramic crowns and 8 pieces full ceramic bridgs for Cosmopost ceramic posts and cores were made. The fitness of Cosmopost ceramic post were checked, and the color of all full ceramic crowns and full ceramic bridgs were checked in clinic. The amount of loosening and broken in all restorations were checked every year in clinic. follow up 2 - 3 years. RESULTS: 1 Cosmopost ceramic post was fracture about 1.5 mm before the full ceramic crown was worn. 227 pieces Cosmopost ceramic posts were perfect. All of the full ceramic crowns and bridgs for full ceramic posts were excellent in color. No loosening and broken cases were checked in 0.5 - 3 years. But the indications of Cosmopost ceramic posts were strict in clinic. CONCLUSION: Cosmopost ceramic post has natural aesthetic effect and good strength. it can be used in clinic.

Adolescent↗
PubMed2003

The single-unit crown: factors for clinical success.

Application of the crown preparation guidelines obtained through theoretical models, laboratory testing and clinical studies provide an evidence-based rationale for clinical practice procedures. The evidence-based rationale has been presented to support basic day-to-day techniques in clinical practice. As new techniques and materials are developed, each should be evaluated carefully prior to clinical use and acceptance.

Crowns↗
PubMed2003

[The research of using TiN nanometer film to improve the anticorrosive property of FeCrMo alloy].

OBJECTIVE: The aim of the study is to improve the anticorrosive property of the dental FeCrMo soft magnetic alloy covered with TiN film obtained by ion beam assisted deposition (IBAD) technology in oral environment. METHODS: The magnetic force of the FECrMo soft magnetic alloy after TiN film treated were measured by Instron test machine. An advanced electro-chemical method was used to measure the electric potential of corrosion (Ecorr), passive potential (Ep), passive current density (Ip), current density of corrosion (Icorr), polarization resistance (Rp), of FeCrMo soft magnetic alloy in simulated oral environment before and after surface modification. RESULTS: There were no statistic changes of the magnetic force in 4 groups after alloy with TiN film treated. Comparing with the alloy without surface modified, the Ecorr, Rp of FeCrMo soft magnetic alloy was obviously higher, and the Icorr, Ip and Ep were obviously lower. CONCLUSIONS: The anticorrosive property of the dental FeCrMo soft magnetic alloy with TiN film is better than that without modified.

Chromium Alloys↗
PubMedDate not supplied

Preload loss in gold prosthesis-retaining screws as a function of time.

PURPOSE: Screwed joints are widely used in implant dentistry, and their failure is a significant problem that may be related to loss of preload. Preload is the compressive force generated across a joint when a screw is tightened and is responsible for keeping a joint closed. For a given torque, preload is limited by the frictional resistance of the contacting screw threads, flange, and opposing joint surfaces. This study tested the hypothesis that following correct placement, prosthetic gold screws lose preload over time. MATERIALS AND METHODS: The study used standard Nobel Biocare components. Strain gauges mounted on a standard abutment formed a transducer to measure preload. Five sets of new prosthetic gold screws, gold cylinders, and standard abutment screws were assembled in turn on the top of an implant body, using the transducer abutment. The gold screws were tightened with a Nobel Biocare Torque Controller set to 10 Ncm, when it had an output of 12.06 +/- 0.8 Ncm with 95% repeatability. Preload was monitored for 15 hours; then the screws were removed and examined under a scanning electron microscope. RESULTS: Preload ranged from 157.5 to 488.9 N (mean 319.6 N), with a mean reduction over 15 hours of 24.9%, with 40.2% of this occurring within 10 seconds of tightening. DISCUSSION: Torsional relaxation of the screw shaft, embedment relaxation, and localized plastic deformation of the gold alloy and opposing titanium threads were the most likely explanation for this phenomenon. CONCLUSIONS: New prosthetic gold screws suffer significant loss of preload following placement.

Compressive Strength↗
PubMedDate not supplied

Salvaging a porcelain/metal bridge with a bonded porcelain-fused-to-metal overcasting.

Porcelain fractures from ceramo-metal fixed bridges often are troublesome for both dentist and patient, especially when problems occur in the anterior region. Repairing these fractures can be a challenge because the repair must be not only durable but also pleasing esthetically. While repair can be achieved with a composite resin material, matching the color and texture with the surrounding intact porcelain often is difficult and the bonding between the resin and porcelain is susceptible to marginal leakage, which may result in esthetic failure. This article reviews a technique designed to salvage a fractured porcelain-fused-to-metal bridge and return it to form and function by utilizing a porcelain-fused-to-metal overcasting.

Acid Etching, Dental↗
PubMed2004

Development of dental implant movement (IM) checker for dental implant mobility assessment.

This study aimed at developing a dental implant movement (IM) checker for assessing quantitative dental implant mobility. The design of the instrument was based on the tooth mobility (TM) tester, which was previously developed by our group. The IM checker consists of a newly developed measuring probe which has the size of a typical dental drill so that it would be easy to measure at all regions of dental implants. The probe has a bimorph ceramics transducer for actuating an implant at constant frequency and force amplitude and for detecting acceleration response. A set of strain gauges were attached to the bimorph ceramics for detecting preload during measurement. A new digital data acquisition system was used to eliminate measurement artifacts mainly due to probe handling. The IM checker could discriminate the artificial dental implant models in the range of clinical tooth mobility M0 with variation less than 6%. The measuring time needed by five operators was less than 15 s. Accordingly, the IM checker has sufficient measuring reliability and therefore it could be introduced in dental clinics.

Dental Implants↗
PubMedDate not supplied

Retrospective evaluation of the success of oral rehabilitation using the Frialit-2 implant system. Part 1: Influence of topographic and surgical parameters.

PURPOSE: This retrospective longitudinal study evaluated the success of implant-prosthetic rehabilitation with the Frialit-2 implant system. MATERIALS AND METHODS: The study was performed with 504 patients, from two treatment centers, who had received a total of 1,554 implants between May 1990 and May 2001. The data of these patients, who received the implants in various regions and for various indications, were analyzed with respect to clinical, topographic, and radiographic parameters. The mean observation period was 6.2 years, with a maximum of 134 months. RESULTS: A survival rate of 94.8% was found for all implants. The implant survival rate of 92.6% in the maxilla remained constant after 68 months of observation. In the mandible, the implant survival rate of 96.7% showed no changes after 76 months. Kaplan-Meier analysis identified jaw, occurrence of postoperative complications, and region as statistically significant factors influencing implant survival. Multivariate Cox regression showed that gender, occurrence of postoperative complications, and jaw were factors that increased the risk of implant loss. Statistically significant correlations were found between the incidence of implant loss and vertical bone loss adjacent to the implant at the time of second-stage surgery. CONCLUSION: Implant survival rate is influenced by implant site, gender, and occurrence of complications. On the whole, the Frialit-2 system proved successful in all areas of indication after long-term observation.

Alveolar Bone Loss↗
PubMed2004

Simulating periodontal effects in dental osseointegrated implants: effect of an intramobile damping element on the fatigue strength of dental implants--an in vitro test method.

OBJECTIVE: The purpose of this study was to develop and adapt a new method for testing dental implant systems and to apply it to existing systems with and without dampers. The parameters examined were the fatigue strength of the superstructure-retaining titanium screw, the deformation of the damper, and the effect on the supporting, bone-stimulating, and embedding material. METHOD AND MATERIALS: Ten pairs of implant specimens were prepared according to standard laboratory procedure and embedded in transparent polymethylmethacrylate (PMMA). Five pairs were provided with polyoxymethylene dampers and five with nondamping titanium connectors. Each pair was connected with a metal beam, and cyclic loads were applied with a pneumatic-driven machine at a frequency of 2 Hz. Chewing forces of 150 to 450 N were transmitted by springs individual to each specimen. For each of the 2 x 10(5) cycles, there was a control of the retaining screw and bonding between the fixture and embedding material by registration of gap propagation in the implant-PMMA interface. RESULTS: A significant damping effect was noticed on the implant--embedding material interface. Damping did affect the superstructure, since the retaining screws were plastically deformed. The screws were unscrewed when the applied load exceeded 300 N, while the undamped system was seemingly unaffected. CONCLUSION: The study method made it possible to evaluate damping effects on different levels of implant systems, while satisfying the requirements for testing in a "clinical-like" way. PMMA was comparable to bone in supporting implants during fatigue testing.

Alveolar Process↗
PubMedDate not supplied

Retrospective analysis of implant survival and the influence of periodontal disease and immediate placement on long-term results.

PURPOSE: The purpose of this study was to investigate the cumulative survival rates of dental implants placed in a private periodontal practice and the effects of periodontal disease and immediate placement on implant survival. MATERIALS AND METHODS: A retrospective chart review was conducted on 149 consecutive patients. Each patient had a single implant placed. For the purpose of analysis, patients were divided into 2 groups: those who were periodontally healthy and those who had periodontal disease. Implants were placed into available bone either immediately or after a healing period. All failed implants were removed and recorded. The effects of periodontal status and placement time on implant survival were evaluated using Cox proportional hazards regression and log-rank tests. RESULTS: Of the 149 implants in the study, 22 failed during the observation period. The 127 censored cases (i.e., implants that had not failed at the end of the observational period) were observed for a mean of 943 days (SD 932, range 35 to 4,030). Failed implants were observed for a mean of 722 days (SD 1,026, range 18 to 3,548). The presence of periodontal disease appeared to be associated with a greater failure rate, but there was no observed effect associated with time of placement. The percentages of censored immediate placement cases and delayed placement cases were nearly identical. Among the 77 implants associated with periodontal disease, placement time was not strongly associated with percentage censored. Forty-three of the 55 immediately placed implants (78.18%) and 18 of the 22 implants (81.18%) whose placement was delayed were censored. Both Cox proportional hazards regression and log-rank tests established that survival was adversely affected by periodontal disease (P < .05) but unaffected by time of placement (P > .50). The lower 1-sided 95% confidence limit for median survival time was 3,548 days for patients without periodontal disease and 1,799 days for patients with disease. DISCUSSION AND CONCLUSION: Implant survival was compromised by a history of periodontitis but not affected by immediate or delayed placement.

Dental Implantation, Endosseous↗
PubMedDate not supplied

Osseointegration of mobile posterior single-tooth implants with SLA surface: report of 2 cases.

The conditions for achieving osseointegration of endosseous implants have been well established. The criteria that validate this result concern the physical properties of the implant (e.g., material, surface properties), its controlled loading, and its primary stability. Theory regarding primary stability has evolved in recent years. Two clinical cases of totally mobile yet eventually successful sandblasted, large-grit, acid-etched implants serve as illustrations of the possible success of implants deprived of primary stability. In certain circumstances, and if certain recommendations are enforced, it may be possible to consider the preservation, with success, of implants that are completely mobile.

Bicuspid↗
PubMedDate not supplied

Alternative bone expansion technique for immediate placement of implants in the edentulous posterior mandibular ridge: a clinical report.

PURPOSE: The aim of this study was to evaluate the effectiveness of a split-crest bone augmentation technique performed for immediate implant placement in thin edentulous posterior mandibular ridges. MATERIALS AND METHODS: In the present study, 125 implants were placed in posterior mandibular ridges of 30 patients. The mandibular buccal walls were split, expanded, and grafted with a combination of platelet-rich plasma and Cerasorb. The split segments were held in place by cortical bone screws. Before loading, periodontal status was checked, implant stability was evaluated with the Periotest, and panoramic radiographs and computerized tomography scans were obtained. Second-stage surgery (cover screw removal and healing abutment placement) was performed after 3 to 4 months. RESULTS: All implants osseointegrated successfully and underwent loading after 4 months. Optimal healing occurred 3 to 4 months earlier than the usual 6 to 9 months required, and no lip paresthesia was noted. DISCUSSION: Although onlay-inlay grafts, sandwich osteotomies, guided bone regeneration, piezoelectricity, and alveolar distraction have been indicated for augmentation in the posterior mandibular region, each of these techniques involves risks and complications. The crest-splitting bone expansion technique enables single-stage immediate implant placement and lateral ridge augmentation in thin crests and may prevent neurosensorial deficiencies. CONCLUSIONS: The split-crest surgical technique is a valid reconstructive procedure for sharp posterior mandibular ridges. If performed using platelet-rich plasma and Cerasorb, it can shorten the osseointegration period.

Alveolar Ridge Augmentation↗
PubMedDate not supplied

A comparison between cutting torque and resonance frequency in the assessment of primary stability and final torque capacity of standard and TiUnite single-tooth implants under immediate loading.

PURPOSE: In this study, standard Brånemark System implants and Brånemark TiUnite implants were evaluated regarding primary stability and placement torque. The correlation between placement torque and primary stability as well as the influence of implant design on placement torque and primary stability were examined. MATERIALS AND METHODS: Twelve patients who presented bilateral loss of either maxillary lateral incisors or premolars were treated with 24 immediately loaded dental implants. Each patient received 1 standard 3.75 x 13-mm Brånemark System implant and one 3.75 x 13-mm TiUnite Mk III implant. One at a time, each implant was connected by a transducer to an Osstell machine that automatically translated a resonance frequency value for the implant into an implant stability quotient value. Osseocare equipment was used to measure the placement torque for both types of implants. RESULTS: Statistical analysis showed higher mean values for standard implants in relation to placement torque and resonance frequency values. DISCUSSION: There was no overall correlation between placement torque and resonance frequency values; this finding supported previous studies. CONCLUSION: Stability was shown to be higher for the standard implants. Mean values of torque resistance were higher for the standard implants than for the TiUnite implants. Implant design appeared to influence primary stability and placement torque.

Adult↗
PubMedDate not supplied

A split-mouth randomized clinical trial of single crowns retained with resin-modified glass-ionomer and zinc phosphate luting cements.

PURPOSE: This study compared the influence of two luting cements on the clinical performance of single crowns. MATERIALS AND METHODS: Twenty patients received 39 pairs of metal-ceramic and Procera crowns cemented with zinc phosphate and resin-modified glass-ionomer luting cement (Vitremer) in a split-mouth randomized pattern blinded to the recipient. The crowns were examined immediately after cementation, after 2 weeks, after 6 months, and then yearly. Clinical performance was scored according to CDA criteria, Silness and Loe criteria, patient satisfaction, and operator-appraised general clinical criteria. Three clinicians in private general practice carried out all procedures. RESULTS: During the observation period, which varied between 80 and 104 months, seven clinical events were recorded. Two abutments fractured vertically, two underwent retrograde endodontic surgery, and one developed pulp necrosis. Two crowns were recemented. Estimated survival, defined as no negative events observed, was 89% at 102 months (85% for crowns cemented with zinc phosphate and 93% for crowns cemented with resin-modified glass-ionomer). Estimated survival, defined as no recementation or loss of pulp vitality, was 96% at 102 months (95% with zinc phosphate and 97% with resin-modified glass-ionomer). The differences between cements were not statistically significant. CONCLUSION: A resin-modified glass-ionomer luting cement was at least as good as zinc phosphate cement to retain single crowns over a 102-month observation period.

Cariostatic Agents↗
PubMed2004

[Risk factors for dental implant inflammation--a literature review].

Replacing missing teeth with osseointegrated dental implants is a predictable technique as evidanced by overall 5-years survival rate that range between 93% to 97%. Few studies, however have adressed the history and frequency of inflammatory complication associated with dental implant. Inflammatory complications are the main cause of failure of dental implants. In this review we classified the inflammatory complications to acute and chronic and to those limited to the hard tissue, to the soft tissue or both. The incidence of the complications is discussed with an emphasis on their risk factors.

Dental Implantation, Endosseous↗
PubMedDate not supplied

Experimental peri-implant tissue breakdown around different dental implant surfaces: clinical and radiographic evaluation in dogs.

PURPOSE: Tissue reactions to 4 different implant surfaces were evaluated in regard to the development and progression of ligature-induced peri-implantitis. MATERIALS AND METHODS: In 6 male mongrel dogs, a total of 36 dental implants with different surfaces (9 titanium plasma-sprayed, 9 hydroxyapatite-coated, 9 acid-etched, and 9 commercially pure titanium) were placed 3 months after mandibular premolar extraction. After 3 months with optimal plaque control, abutment connection was performed. Forty-five days later, cotton ligatures were placed around the implants to induce peri-implantitis. At baseline and 20, 40, and 60 days after placement, the presence of plaque, peri-implant mucosal redness, bleeding on probing, probing depth, clinical attachment loss, mobility, vertical bone loss, and horizontal bone loss were assessed. RESULTS: The results did not show significant differences among the surfaces for any parameter during the study (P > .05). All surfaces were equally susceptible to ligature-induced peri-implantitis over time (P < .001). Correlation analysis revealed a statistically significant relationship between width of keratinized tissue and vertical bone loss (r2 = 0.81; P = .014) and between mobility and vertical bone loss (r2 = 0.66; P = .04), both for the titanium plasma-sprayed surface. DISCUSSION AND CONCLUSIONS: The present data suggest that all surfaces were equally susceptible to experimental peri-implantitis after a 60-day period.

Alveolar Bone Loss↗