Taking your practice to a new level. Part II.

There is a new game in the dental profession with new rules of competition. The new game has to do with creating patient value. With this game, good no longer is good enough.     

Silicoating: evaluation of a new method of bonding composite resin to metal

Abstract — Silicoating is a new type of pretreatment of the metal in the resin-bonded bridge technique. The size of bond strength between resin cement and silicoated metal was investigated. Different resin cements, types of metal, and grain sizes of sand used for roughening the metal surface were tested. Furthermore, the effect on the bond strength of contamination with saliva and of thermocycling was measured. There was no difference of importance between the two resin cements tested. Bond strengths obtained with Wirobond were the highest and insensible to changes in resin cement, grain size of sand, and to thermocycling. It was found that sand of the smallest grain size used brought about the highest bond strengths. Contamination with saliva did not significantly reduce the size of the bond strengths. Rinsing the metal surfaces with water or ethanol after contamination restored the bond strengths to their original magnitude. By silicoating, a greater resistance to thermocycling was obtained. Nevertheless, except for Wirobond, a fall in bond strength was measured after thermocycling. Bond strengths of the size of those between etched enamel and composite resin were measured, and the Silicoater method seems a reliable pretreatment of the metal.     

Silicoating: evaluation of a new method of bonding composite resin to metal

Silicoating is a new type of pretreatment of the metal in the resin-bonded bridge technique. The size of bond strength between resin cement and silicoated metal was investigated. Different resin cements, types of metal, and grain sizes of sand used for roughening the metal surface were tested. Furthermore, the effect on the bond strength of contamination with saliva and of thermocycling was measured. There was no difference of importance between the two resin cements tested. Bond strengths obtained with Wirobond were the highest and insensible to changes in resin cement, grain size of sand, and to thermocycling. It was found that sand of the smallest grain size used brought about the highest bond strengths. Contamination with saliva did not significantly reduce the size of the bond strengths. Rinsing the metal surfaces with water or ethanol after contamination restored the bond strengths to their original magnitude. By silicoating, a greater resistance to thermocycling was obtained. Nevertheless, except for Wirobond, a fall in bond strength was measured after thermocycling. Bond strengths of the size of those between etched enamel and composite resin were measured, and the Silicoater method seems a reliable pretreatment of the metal.     

Innovations in bonding to zirconia-based materials. Part II: Focusing on chemical interactions

ObjectivesThe zirconia–resin bond strength was enhanced using novel engineered zirconia primers in combination with selective infiltration etching as a surface pre-treatment. The aim of this study was to evaluate the effect of artificial aging on the chemical stability of the established bond and to understand the activation mechanism of the used primers.MethodsSelective infiltration etched zirconia discs (Procera; NobelBiocare) were coated with one of four novel engineered zirconia primers containing reactive monomers and were bonded to resin-composite discs (Panavia F2.0). Fourier transform infrared spectroscopy (FT-IR) was carried out to examine the chemical activation of zirconia primers from mixing time and up to 60 min. The bilayered specimens were cut into microbars (1 mm² in cross-section area) and zirconia–resin microtensile bond strength (MTBS) was evaluated immediately and after 90 days of water storage at 37 °C. Scanning electron microscopy (SEM) was used to analyze the fracture surface.ResultsThere was a significant drop in MTBS values after 90 days of water storage for all tested zirconia primers from ca. 28–41 MPa to ca. 15–18 MPa after completion of artificial aging. SEM revealed increase in percentage of interfacial failure after water storage. FTIR spectra suggested adequate activation of the experimental zirconia primers within 1 h of mixing time.SignificanceThe novel engineered zirconia primers produced initially high bond strength values which were significantly reduced after water storage. Long-term bond stability requires developing more stable primers.     

Adhesion of adhesive resin to dental precious metal alloys. Part I. New precious metal alloys with base metals for resin bonding

New dental precious metal alloys for resin bonding without alloy surface modification were developed by adding base metals (In, Zn, or Sn). Before this, binary alloys of Au, Ag, Cu, or Pd containing In, Zn, or Sn were studied for water durability and bonding strength with 4-META resin. The adhesion ability of the binary alloys was improved by adding In equivalent to 15% of Au content, Zn equivalent to 20% of Ag content, and In, Zn, or Sn equivalent to 5% of Cu content. There was no addition effect of the base metals on Pd, however 15% of In addition improved adhesion with Pd-based alloys containing equi-atomic % of Cu and Pd. The alloy surfaces were analyzed by XPS and showed that oxides such as In2O3, ZnO, or SnO play an important role in improving the adhesive ability of the alloys.     

Patient response to variations in denture technique. Part II: five-year cephalometric evaluation.

This study was designed to determine if differences in rates of residual alveolar bone loss could be found in patients wearing dentures made by a complex technique and a standard technique. Cephalometric radiographs were made for each of 64 patients at initial placement of the dentures and for all active patients at five yearly recall visits. These radiographs were measured to determine rates of mandibular bone loss, maxillary bone loss, loss of total face height, rotation of the mandible, and migration of the denture bases over the 5-year period. At the end of the study no statistically significant differences between the two groups of patients could be found. Examination of all participants in this study revealed rates of bone loss that were very similar to those reported by other investigators.     

Development of a new endosseous dental implant. Part II: Human studies

The development of an endosseous implant has followed a logical and formal plan.

1. Extensive experiments with animals provided preliminary statistics of successful function, extensive histologic studies, evaluation of biocompatibility, and a preliminary assessment of contraindications.

2. Carefully developed and controlled clinical study of human subjects with frequent examinations and detailed records of both successes and failures again provided new bases for contraindications.

The statistics on the clinical study are satisfactory in their results, although they should be regarded as having a somewhat conservative slant. This is because implant failures became a learning base for improved procedures.The program so far has been limited to a single implant design that, with size variants, will serve most applications. However, it is not feasible to modify the design in terms of dimensions for application in the anterior portion of the mouth. A design for this purpose is established on paper and will become a future additional development.