Thomas J. Bloem

Microbial colonization of dental implants in partially edentulous subjects

This study assessed the colonization of Brånemark dental implants by periodontopathic bacteria in four partially edentulous patients with a total of 10 implants. Marginal and subgingival plaque on the implants was sampled 14 days and 28 days after second-stage surgery and compared with plaque from three teeth closest to the implant sites sampled before second-stage surgery (baseline) and at 14 and 28 days. Slot immunoblot assay was used to determine the presence or absence of bacterial antigen to six different periodontopathic microorganisms. In general, colonization of marginal implant plaque occurred within 14 days, whereas subgingival colonization took longer and occurred within 28 days. It appears that Brånemark dental implants placed in partially edentulous patients may be colonized by disease-associated bacteria within 14 days of second-stage surgery.

In vivo wear. Part I: The Michigan computer-graphic measuring system

Three-dimensional coordinate measuring machines for examining the quality of industrial castings were reviewed. The concept was modified and successfully converted to examine the minute geometric configurations of the surfaces of dental materials. The wear of composites has undoubtedly precipitated this perceptive, thorough study.

The effects of two air-powder abrasive prophylaxis systems on the surface of machined titanium: a pilot study.

This in vitro pilot project compared the effect of two air-abrasive prophylaxis systems on the surface of machined titanium. Single Brånemark titanium abutment cylinders were exposed to the Prophy-Jet and Microprophy systems for 90 seconds each. Both of the test cylinders were compared with an untreated control cylinder by scanning electron microscopy. Machining marks were completely removed by the Prophy-Jet and only partially removed by the Microprophy. Both of the resultant surfaces appeared to be smoother and thus may be more resistant to plaque formation. A rationale for the removal of machining marks is presented, although the reason for the difference in removal by the two systems is unclear. The prophylaxis cleaning powders were also examined by scanning electron microscopy and exhibited similar particle dimensions and morphology. A noncrystalline deposit was observed on the surface of the abutment cylinder exposed to the Microprophy. Energy dispersive spectroscopy analysis revealed that the deposit consisted almost entirely of sodium. Further investigation of the deposit is needed. (Implant Dent 1992;1:259–265)

Determination of the accuracy of three die systems

This article reports the findings of two interrelated projects that measured the accuracy of electroplated, epoxy resin, and polyurethane die materials against a master tooth, using the Michigan Computer Graphics Coordinate Measuring System (MCGCMS). In the first phase, on occlusal die morphology, replications of a master tooth were used to validate the MCGCMS reliability. Eighteen total data sets derived from three silver-plated dies and three epoxy resin dies were then compared with a representative data set of the master tooth. The mean differences for all silver-plated die and epoxy die measurements against the master ranged from -42 to -49 and -46 to -230 microns/mm2, respectively. In the second phase, two epoxy die materials and a polyurethane system were compared with a master tooth in an identical manner. In paired comparisons to the master tooth, mean differences for Epoxydent material, epoxy resin, and polyurethane dies ranged from -147 to -153, -149 to -230, and -56 to -168 microns/mm2, respectively. A Student t test using a CLR ANOVA was performed between the master tooth and the five die systems. A significant difference was revealed between the enamel-silver difference and the enamel-Epoxydent difference data at the 95% confidence level. A significant difference also occurred between enamel-silver and enamel-epoxy resin. It was concluded that silver-plated dies are acceptable replicas of a master tooth. Epoxydent and epoxy resin dies did not provide reliable replications when compared with the silver-plated dies. Epoxy and polyurethane replications, although reported as accurate, were inconclusive.

Denture plaque control and inflammation in the edentulous patient

The relationship between denture base plaque and mucosal inflammation under complete dentures was tested by clinical comparison with the PTI and a comparable plaque-scoring technique. Two treatment groups, one of which practiced tissue-brushing only and the other denture-brushing only, were compared with a control group with regard to mucosal inflammation and denture plaque score. Significant reduction in inflammation occurred, although no reduction in denture base plaque score was found. The effect of denture plaque on denture stomatitis and the efficacy of denture-brushing as a plaque removal technique is challenged.