Biomedical subjects

M C van Putten

Publications and source records attributed to M C van Putten.

6 recordsLinked to original sources

PubMed2000

Adhesion testing of a denture base resin with 5 casting alloys.

PURPOSE: This study compared denture base resin shear bond strengths to silicoated Au-Pd, Au-Pd-Ag, Au-Ag-Pd-Cu, high-Pd, and Ni-Cr-Be alloys used to fabricate frameworks for hybrid implant prostheses. Microleakage between alloy and resin was also compared among groups after specimen fracture. MATERIALS AND METHODS: Twelve cylindrical specimens were cast for each alloy. Each specimen was made from a ring-shaped pattern (diameter [d] = 12 mm and height = 4 mm) and machined to achieve uniform hollow centers (d = 6.5 mm). Castings were abraded with 250-micron aluminum oxide and ultrasonically cleaned in distilled water before silicoating. Denture base resin was processed to the internal surfaces of the silicoated specimens. All specimens were thermocycled (1,000 cycles) between 4 degrees C and 50 degrees C, and placed in basic fuchsin dye for a week. A punch (d = 3.8 mm) driven at a cross-head speed of 0.5 mm/min was used to push out the resin specimens. The force required to cause failure was converted to the nominal shear bond strength for each specimen, and mean shear bond strengths for the 5 groups of specimens (N = 12) were compared using one-way analysis of variance and the Tukey-Kramer HSD multiple range test (alpha = 0.05). Six of the 12 debonded resin samples for each alloy were selected at random and evaluated for dye penetration. Using an 80-square grid, the percentage of dye penetration was evaluated with an optical microscope (x25) to determine the percentage of grid area penetrated by the dye. One-way analysis of variance was used to compare the degree of microleakage among groups. RESULTS: The mean resin-alloy shear bond strengths for the Au-Pd (9.6 +/- 3.7 MPa) and Au-Ag-Pd-Cu (9.2 +/- 1.5 MPa) alloys were significantly greater than mean resin-alloy shear bond strength for the Au-Pd-Ag alloy (5.6 +/- 1.9 MPa). No other significant differences in resin-alloy shear bond strengths were noted among the alloy groups. No significant differences were noted for dye penetration into the resin specimens bonded to any of the 5 alloys. The mean grid area penetrated by the dye was 25% when results for the alloys were pooled. CONCLUSIONS: Alloy type influences the shear bond strength of a denture base resin to silicoated alloys, but no difference in bond strength was found between Au-Pd, Au-Ag-Pd-Cu, high-Pd, and Ni-Cr-Be alloys. In addition, under the conditions of this study, all groups showed a similar degree of microleakage, which penetrated approximately 25% of the bonded specimen surface area.

Air Abrasion, Dental↗

PubMed1996

Use of the Internet for educational applications in prosthodontics.

Internet is the common term for the information superhighway. The Internet has become a major information resource for educational, governmental, and business institutions. This article reviews the current operation of the Internet as a background for discussing educational opportunities for instruction in prosthodontics. Electronic mail, news groups, file transfer protocol, Gopher, and network navigators are discussed. The use of the World Wide Web for educational purposes by The Ohio State University College of Dentistry Department of Restorative and Prosthetic Dentistry is described.

Computer Communication Networks↗

PubMed1995

The use of clinical computer workstations as an educational adjunct in prosthodontics.

Current computer systems improve the health professional's ability to store, retrieve, and present visual data in a way never before possible. Health professionals in general are beginning to use computer-based digital imaging to improve the diagnosis and treatment planning of disease processes. The use of computer-based networks to transmit medical and dental data is in its infancy but promises to be the main form of data transmission of the future. This article outlines a few applications presently being used and developed at the Ohio State University College of Dentistry in the preclinical and clinical courses in prosthodontics.

Computer Communication Networks↗

PubMed1994

Adhesion promotion between metadent and a high palladium alloy with a pyrolytically fused porcelain opaque layer.

PURPOSE: Several authors have reported a preference for the use of high palladium alloys in the construction of implant-fixed partial denture (IFPD) substructures. Heat-polymerized polymethyl methacrylate resins (PMMR) are used to secure denture teeth to IFPD substructures. Metadent (Sun Medical Co, Kyoto, Japan), a heat-polymerized PMMR containing 5% 4-methacryloxyethyl trimellitate anhydride (4-META), could possibly improve the overall design of the prosthesis because this resin adheres to resin and ceramic denture teeth and noble metals. However, adhesive bonding between Metadent and elemental palladium has been shown to be poor. The purpose of this study was to evaluate the potential for adhesive bonding between Metadent, titanate primers, and a ceramic layer pyrolytically fused to a high palladium alloy. MATERIALS AND METHODS: Five groups of 10 specimens were prepared. A layer of opaque porcelain was baked on all of the specimens under vacuum at 1760 degrees F. The specimens were grouped as follows: (1) Metadent resin processed on ceramic with no primer, (2) Metadent resin with 10% ethyl acetoacetate titanate (DC) processed on ceramic with no primer, (3) Metadent resin with 10% DC processed to ceramic with a 2% tetraisopropyl (TPT) surface primer, (4) 4-Metadent resin with 10% DC processed to ceramic with a 2% isopropyl dimethacryloyl isostearoyl titanate (KR-7) surface primer, and (5) Metadent resin with 10% DC processed to ceramic with a titanium dioxide layer on the opaque and a KR-7 surface primer. The primers were in a methyl methacrylate (MMA) solution. All of the specimens were heat-polymerized under pressure at 212 degrees F for 1 hour. One-half (25) of the specimens (5 from each group) were hydro-thermocycled at 4 degrees C to 55 degrees C, 0.5 minute dwell per bath for 3,000 cycles. All specimens were tested in shear on an MTS Universal machine at cross head speeds of 0.5/mm/min. RESULTS: The results showed adhesion between the resin-ceramic layer in virtually all groups regardless of thermocycling effects. The control (heat cure without 10% DC and no primer) and the 10% DC with KR-7 and TPT primer groups had an average MPa of 7.5, 7.7, and 7.0, respectively. The failure mode of the specimens was adhesive, with the site of failure being the porcelain-metal interface. CONCLUSION: It was concluded that adhesion between palladium alloy and Metadent was possible when a ceramic layer was used as an intermediary interface. The limitation seemed to be the adhesion of the ceramic to the metal.

Acrylic Resins↗

PubMed1992

Alloplastic cranial implants made from computed tomographic scan-generated casts.

The complexity of cranioplasty increases with increased defect size. It is difficult to produce a symmetric, accurate implant presurgically or at the time of surgery when the defect is greater than 50 cm2. The procedure is also more difficult to perform when the defect is located in the temporal, infratemporal, or frontal areas. A new procedure generates a three-dimensional cast of the skull through computed tomography and computer-aided design reformation. This article describes the process of model generation and the production of a preprocessed cranial implant. To date, six cranial implants have been made with this technique. The whole head models are accurate and help the neurosurgeon-prosthodontist team in the creation of a symmetric, anatomically correct restoration. It is the technique of choice for large implants or where the cranial bones are thin. It is not necessary to augment or alter the implant during surgery. The technique reduces surgical time, and postsurgical complications have been minimal.

Artificial Intelligence↗

PubMedDate not supplied

Comparison of strains produced in a bone simulant between conventional cast and resin-luted implant frameworks.

Complete-arch implant prostheses continue to exhibit horizontal and vertical misfit between frameworks and abutments. It has been suggested that these gaps may be eliminated and that restoration-induced stresses may be reduced by luting frameworks to screw-retained abutments intraorally. This study measured and compared the strains generated by clinically acceptable, conventional frameworks were made from a single master cast representing a bone simulant model of an edentulous mandible with five Nobel Biocare implants and 4-mm abutments. Two strain gauges were also embedded in the bone simulant model to measure strains at two locations. Resin-luted frameworks were made by securing abutments to the clinical model with five gold slot screws tightened to 10 Ncm. Strain-indicator readings were recorded at a standardized time following the initial fastening of each prosthesis (n = 3). Mean principal strains were determined and compared using a one-way repeated measures analysis of variance. A statistically significant difference was found in the principal strains between the conventional cast and the resin-luted frameworks. Overall, there was a decrease in the magnitude of strain for the resin-luted frameworks. Intraoral luting of frameworks may decrease the strains produced in the bone around implants.

Analysis of Variance↗