Wear Of Restorations Research Articles

Four-year in vivo evaluation of the composite/bonding resin-tooth interface

The objective of this study was to evaluate the color match, marginal discoloration, recurrent caries, anatomic form, and marginal adaptation of 41 paired Class III and Class V preparations restored with a conventional chemically cured resin composite with and without a low-viscosity bonding resin (LVBR). In addition, the wear of the restorations was evaluated from scanning electron micrographs of epoxy replicas of the restorations. The subjects were re-called 48 months after placement of the restorations. The marginal discoloration and wear of the composite restorations placed without a LVBR were significantly greater than in restorations placed with a LVBR. The results of this clinical study suggest that a LVBR should be applied prior to the placement of a conventional chemical-activated resin composite.

Wear of prosthodontic materials—an in vivo study

The aim of this investigation was to study quantitative and qualitative aspects of the wear process of some prosthodontic materials in three different persons in vivo. The in vivo models combined two methods: removable double crowns and a replica technique. The wear resistance of gold (types III and IV), porcelain and a microfilled resin was studied opposing metal ceramic crowns and in one person when opposing all four materials. All three persons had earlier histories of occlusal wear of teeth and/or restorations. The wear rate of gold and porcelain showed equal values antagonizing metal ceramic crowns in all three persons. The microfilled resin had a wear rate three or four times higher in the same situations. No significant difference in wear resistance could be found between type III and type IV gold alloys. The wear mechanism seemed to be a fatigue type in porcelain, and in gold a combined fatigue and abrasive type of wear. The microfilled resin showed mainly a fatigue type of wear but some observations indicating a tribochemical reaction were also made.

Wear behavior of a composite restorative and various styli in sliding contact.

Using a pin-on-disc sliding-wear test apparatus, the wear behavior of a typical composite restorative vs. styli fashioned from human enamel, sintered alumina, and magnesium fluoride was examined. The rates of restorative wear were found to be identical, within the experimental error of the measurements, for tests using either human enamel pins or styli fabricated from sintered alumina. Moreover, these two pin materials generated morphologically similar wear-tracks in the restorative disc. Thus, styli of sintered alumina produce restorative wear that is both qualitatively and quantitatively analogous to that observed in tests using human enamel pins.

Studies on the occlusal wear of posterior composite resin restorations. Part 2. Clinical evaluation

Resistance to the occlusal wear of the composite resins for posterior use was investigated by using the new measuring method described in the previous paper. Sixty-seven Class I molar cavities were restored with Clearfil Bond System-F (CF) as anterior resin, with Clearfil Posterior (CP), K-G Composite Resin (KG) and GC Microrest Jar Type (MJ) as posterior resin and with Shof u Spherical-D (SD) as amalgam.The degree of the occlusal wear of the restorations was mainly estimated at 6-month intervals after the insertion up to the two-year period. The wear surface was also observed by the SEM images on the replicas.The findings obtained were follows:1. The amount of the occlusal wear of the various restorations was 2 μm/year with the SD, 4 μm/year with the MJ, 13 μm/year with the KG, 16 μm/year with the CP and 40 μm/year with the CF.2. The MFR resorations were the severest, when they were in close occlusal contact.3. The worn surface was the roughest with the CF, followed in order by KG, CP, MJ and SD.4. Correlation between the cavity width and the amount of wear of the composite resins was not observed.5. The restorations are generally considered to be subjected to the repeated abrading stress by the food fibril during the chewing process.