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Biomedical subjects

L Pröbster

Publications and source records attributed to L Pröbster.

33 records · Page 2Linked to original sources
PubMed1990

[SEM study of failures in acid etched cast prosthodontics].

Eight bonded prosthodontic units (mean wearing time 14 months), with 7 retainers spontaneously debonded during clinical use and 9 retainers removed by the dentist, have been studied by SEM. Since only bond fractures at the acrylic/metal interface and mixed fractures could be detected, it may be concluded that late failure is governed by processes at the interface between metal and acrylic. The lost retainers showed overgrowth of mainly rod-shaped bacteria, although one of the artificially removed retainers that was clinically stable beforehand, also exhibited bacterial overgrowth. This suggests that sequential debonding is possible; hence bonded retainers impart a longterm caries risk to abutment teeth.

Acrylic Resins↗
PubMed1990

[Comparison of two computer-aided recording systems: MT 1602 and Compugnath].

Two computer-aided jaw movement recording systems were compared with each other. The results showed that both systems work satisfactorily for use in reconstructive dentistry and TMJ diagnosis. It is, however, emphasized, that there are a number of shortcomings which may have a negative effect on the recordings.

Dental Articulators↗
PubMed1990

[Special ceramic hard substances as separating agents in cast-on procedures for the construction of precision attachments].

A new direct cast-on technology for the construction of telescopic crowns and precision attachments using non-precious alloys is described. Special ceramic hard substances, such as silicides and borides, are used as separating agents for the casting of the secondary structure. The application of the ceramic layers to the primary crown is accomplished with a chemical vapor deposition method. The layer thickness can be controlled and may range between some hundred nanometres and up to a few micrometres. The attainable gaps between primary and secondary casting range between 1 and 8 microns after separating and finishing.

Crowns↗
PubMedDate not supplied

Are ABH antigenic determinants on human outer ear canal epithelium responsible for Pseudomonas aeruginosa infections?

The outer ear canal expression of ABH human blood group antigens has been analyzed with a standardized routine histological procedure by monoclonal antibodies in the case of blood groups A and B, and a corresponding lectin in the case of blood group 0, respectively. In all 20 cases the blood groups were histochemically confirmed. Furthermore, Pseudomonas aeruginosa-specific inhibition experiments were performed with different sugar solutions as well as A-like substance incubating outer ear canal tissue sections with P. aeruginosa strain (No. 60) presenting lectin specificity for N-acetyl-galactosamine (GalNAc). P. aeruginosa lectins with GalNAc specificity apparently adhere to GalNAc as terminal blood group A determinant and indicate that patients presenting with blood group A may have a genetic predisposition to this form of otitis externa.

ABO Blood-Group System↗
PubMedDate not supplied

Compressive strength of two modern all-ceramic crowns.

This study investigated the compressive strength of all-ceramic crowns manufactured using two recently introduced systems. The mean forces of fracture were 964 N for In-Ceram crowns, 814 N for paint-on IPS Empress crowns, and 750 N for layered IPS Empress crowns, compared with 1,494 N for metal ceramic crowns veneered on a nickel-chromium coping. The results indicate that clinical testing of these all-ceramic crowns is reasonable. Controlled, clinical, long-term evaluation is necessary to assess the safe application of these new crown systems.

Aluminum Oxide↗
PubMedDate not supplied

Survival rate of In-Ceram restorations.

This paper reports on 76 consecutively placed In-Ceram restorations (61 complete-coverage crowns and 15 fixed partial dentures). Their survival rates were determined using the Kaplan-Meier method. During the 35-month observation period no crown failures occurred, a five-unit fixed partial denture fractured, and another fixed partial denture was removed because of periodontal complications. Thus, In-Ceram complete-coverage ceramic crowns are apparently indicated for anterior and posterior teeth. A larger number of subjects must be studied to assess the indication for all-ceramic fixed partial dentures.

Adult↗
PubMedDate not supplied

Clinical follow-up study of ceramic veneered titanium restorations--three-year results.

Eighty-four titanium restorations having 125 ceramic veneers were placed for 32 patients. One hundred sixteen (93%) of the veneers could be reexamined after 21 to 41 months. Two of the restorations required removal because of a partial veneer loss. A Kaplan-Meier survival analysis was performed, giving a survival probability of .85 for single crowns and .59 for fixed partial dentures after a time interval of 30 months, regarding the veneer cracking or chipping. There was a significantly higher survival probability for single crowns than for fixed partial dentures (P=.001, logrank test). It was concluded that ceramic veneered titanium restorations should be limited to single crowns.

Chi-Square Distribution↗
PubMedDate not supplied

Copy-milled all-ceramic Celay-InCeram crowns for modified CeraOne abutments: a technical report.

With single-tooth implant restorations, a divergence between implant and crown axes, a lack of interocclusal space, and supracrestal implant placement may result in fabrication problems for the prosthetic crown. It was found that the CeraOne abutment can be modified in three ways: (1) height reduction is possible; (2) a 15-degree taper can be applied; and (3) the cervical shoulder can be reduced in height with a chamfer remaining. For these modified abutments, the Celay-InCeram system was used to create individual, all-ceramic crowns for these modified abutments with improved esthetics.

Aluminum Oxide↗
PubMedDate not supplied

The influence of different cementation modes on the fracture resistance of feldspathic ceramic crowns.

One hundred twenty pressed feldspathic ceramic crowns were luted to 20 steel dies using six different cementation modes. Fracture resistance was tested under an angle of 45 degrees and was determined as the maximal fracture load. Crowns were tested with luting agent only (groups A and C) and after etching with hydrofluoric acid, silanating, and the application of a bonding agent (groups B, D, E, and F). The resulting means were: phosphate cement 294.3 (A) and 282.2 (B); glass-ionomer cement 217.2 (C) and 255.4 (D); resin composite 382.2 (E) and 687.6 (F). Statistical analysis revealed significantly greater fracture resistance (P < .01) of resin luted crowns. Bonding to the die almost doubled the fracture resistance. Conditioning of the inner surfaces of the crowns did not improve the fracture resistance of crowns luted using zinc phosphate or glass-ionomer cements.

Acrylates↗