ABSTRACT
In a randomized clinical study 47 titanium and gold-alloy fixed partial dentures (FPDs) were placed during a 1-year period. In the titanium group (n = 22) all metal substructures were made of unalloyed titanium. The titanium substructures were fabricated by copy milling, spark erosion and laser welding (Procera, Nobelpharma). Ceramic veneering was carried out with Duceratin titanium ceramics (Ducera, Germany). In the control group (n = 25) the high-gold alloy Degudent U (Degussa, Germany) and Vita VMK 68 ceramics (Vita, Germany) were used. The longest observation time was 6 years. Only one FPD had to be removed due to metal-ceramic failure (titanium group). The clinical performance of all 125 porcelain-fused-to-metal (PFM) veneers with respect to the longevity of the metal-ceramic compound was described by Kaplan-Meyer survivor analyses. Relating survival to a completely intact ceramic veneer, the 5-year survivor rate was 84% for titanium and 98% for the high-gold alloy. PFM titanium restorations exhibited a significantly increased risk of metal-ceramic failure. However, concerning defects requiring removal, no significant differences in titanium versus high-gold alloy occurred. There were no significant differences in the survival distributions between crowns and pontics within the two groups.
Subject(s)
Dental Porcelain , Denture, Partial, Fixed , Gold Alloys , Metal Ceramic Alloys , Titanium , Adult , Aged , Crowns , Dental Alloys/chemistry , Dental Casting Technique , Dental Porcelain/chemistry , Dental Restoration Failure , Dental Soldering , Dental Veneers , Denture Design , Electrochemistry , Female , Follow-Up Studies , Gold Alloys/chemistry , Humans , Lasers , Male , Metal Ceramic Alloys/chemistry , Middle Aged , Risk Factors , Survival Analysis , Titanium/chemistryABSTRACT
In 37 patients 88 titanium restorations were placed during a 1-year period 1990-91. The 69 crowns and 19 fixed partial dentures comprised 147 prosthodontic units. All restorations were fabricated by duplication milling and electrical discharge machining of pure titanium (Procera Technology, Nobelpharma, Gothenburg, Sweden). Based on the results of clinical follow-up, Kaplan-Meier survivor functions were calculated. The survivor rate of 40 metal crowns and pontics was 100%. In 107 porcelain-fused-to-metal units the 3-year survivor rate concerning removal was 95%. When relating the survival to an intact ceramic veneer, the 3-year survivor rate of porcelain-fused-to-metal units was 84%. The quality of the restorations evaluated by the rating system of the California Dental Association was found to be satisfactory in the vast majority of cases. It can be concluded that machined titanium restorations are suitable for clinical use, although not all problems, especially in the field of metal-ceramics have yet been completely solved.
Subject(s)
Crowns/standards , Denture, Partial, Fixed/standards , Titanium , Dental Porcelain , Evaluation Studies as Topic , HumansABSTRACT
The problems encountered in casting titanium in dentistry have not been completely resolved. The Procera system forms crowns by means of a combination of spark-erosion and milling. The accuracy of fit was examined before and after ceramic veneering both in vitro and in vivo. Before veneering, on conical surfaces space widths were approximately 53 microns in vitro and 69 microns in vivo. At shoulders and occlusal surfaces, spaces of about 430 microns were measured in vitro and of about 500 microns were measured in vivo. After ceramic veneering, slight increases in space widths could be observed. The metal-ceramic compound was tested by the 3-point bending test (DIN) and the bending test (ISO). The DIN test was satisfactory, but not the ISO test. It is concluded that titanium crowns processed by the Procera System are suitable for clinical usage, if the space widths at shoulders and the occlusal surface and the special requirements of tooth preparation are taken into account.
Subject(s)
Crowns , Denture Design , Denture, Partial, Fixed , Titanium/chemistry , Ceramics/chemistry , Dental Bonding , Dental Casting Technique , Dental Soldering , Dental Veneers , Elasticity , Electrochemistry , Humans , In Vitro Techniques , Lasers , Metallurgy , Stress, Mechanical , Surface PropertiesABSTRACT
In a clinical study the accuracy of fit of 82 crowns manufactured with the Procera-system (duplication milling/spark erosion) was investigated. The average marginal space width was 71 microns. Roughness of eroded surfaces was found to be similar to that of coarsely ground metal. Below the eroded areas a zone of increased hardness with a width of approximately 20 microns was demonstrated.
Subject(s)
Crowns , Dental Polishing/methods , Metal Ceramic Alloys , Titanium , Surface PropertiesSubject(s)
Dental Casting Technique , Dental Enamel Hypoplasia/rehabilitation , Adult , Dental Polishing , Electrolysis , Female , Humans , Malocclusion/therapy , TitaniumABSTRACT
In a study of 703 resin-bonded fixed partial dentures, the success rates of two groups were analyzed where rebonding or renewals were necessary. Results revealed that rebonding often leads to repeated failures whereas renewals showed a failure rate similar to the whole of the investigated material.
Subject(s)
Dental Bonding , Denture Repair/methods , Denture Retention/statistics & numerical data , Denture, Partial, Fixed/statistics & numerical data , Bias , Dental Cements , Humans , Prosthesis FailureABSTRACT
This second report establishes that the success of treatment with resin-bonded bridges was dependent upon many factors. Factors controlled by the clinician, such as case selection and treatment planning greatly influence the clinical success. It was possible to show that framework preparation and the amount of available enamel were significant factors, whereas isolation technique, type of retention mechanism and type of adhesive used were of less importance. Longitudinal studies are needed to confirm these observations. Seventeen clinicians placed 496 resin-bonded bridges and splints with different retention mechanisms and bonding agents. These reconstructions were examined in regard to the failure rate and in regard to reattachment problems. Ninety-seven per cent of the bridges and 90% of the splints were still in place after 1 year. For bridges and splints a 90% success rate was ascertained after 2 years.
Subject(s)
Dental Bonding , Denture, Partial, Fixed , Splints , Adhesives , Adult , Cross-Sectional Studies , Dental Abutments , Dental Bonding/methods , Denture Design , Denture Retention , Female , Humans , Male , Prosthesis Failure , Retrospective Studies , Risk FactorsSubject(s)
Dental Bonding , Denture, Partial, Fixed , Denture Design , Humans , Patient Care PlanningABSTRACT
In a joint evaluation of 496 resin-bonded bridges and splints anchored by various retention principles and composites, the initial experiences of seventeen clinicians were compiled. The main indications for treatment were congenital anodontia and loss of teeth due to caries and trauma. After 3 months, 95% of the bridges were still in place without need of reattachment procedure. After 6 months the figure was 91%, after 1 year 81.5% and after 1 1/2 years 73%. Seventy-five per cent of the loosened bridges were attached successfully a second time. The success rate for splints was significantly lower.
