Advances in restorative materials.

This article has presented basic up-to-date information concerning the selection, properties, and clinical uses of current restoratives that are tooth colored and adhesive. This area in dentistry is advancing at an exponential rate, and it is essential that all practitioners pay constant attention to the information about all materials as they appear on the market. Coupled with a thorough knowledge of treatment planning and case design, results such as seen in Figure 4 make restorative practice a rewarding endeavor for clinicians and patients. Interest in the scientific background, development, and performance of restorative materials must be at a high level to avoid being snared by advertising promises.

Aluminum oxide air abrasion particles: a bacteriologic and SEM study.

OBJECTIVE: The objective is to determine if aerobic and anaerobic sampling yields viable biologic contaminants in the aluminum oxide air abrasion powder as delivered by the manufacturer and to determine mean particle size for comparison with the published size from manufacturers and the range of sizes in the powders. METHOD AND MATERIALS: Samples from 15 unopened aluminum oxide powder containers from 9 different manufacturers were plated on aerobic and anaerobic culture media. The cultures were incubated at 35 degrees C and observed at 24-hour intervals. Samples of each of the 15 groups were subjected to scanning electron microscope (SEM) examination. Photomicrographs were obtained and a range and mean particle size determined. RESULTS: Aerobic and anaerobic cultures demonstrated no growth in any of the samples. Mean particle size determined by SEM for 25- to 27.5-micron particles ranged from 27.3 microns to 32.0 microns with standard deviations from 1.06 microns to 7.70 microns. Mean particle size for 50 microns particles ranged from 51.6 microns to 59.7 microns with standard deviations of 5.48 microns to 14.80 microns. CONCLUSION: Aluminum oxide powders as delivered by manufacturers appeared to be free from viable microorganisms. The powder mean particle sizes approximate the labeled sizes closely enough such that they should perform properly in air abrasion tooth preparation.

The effect of autoclaving and polishing techniques on energy transmission of light-curing tips.

OBJECTIVE: The purpose of this study was to investigate if autoclaving light-curing tips in sterilization packages using a properly maintained autoclave filled with distilled water reduced the buildup of boiler scale and allowed the tips to maintain their ability to transmit energy. METHOD AND MATERIALS: Thirty light-curing tips were divided into groups: control, never autoclaved; group 1, no light-curing tip treatment, autoclaved only; group 2, autoclaved and treated with the Demetron/Kerr Optics Maintenance Kit; group 3, autoclaved and treated with the EFOS Fiberoptic Cleaning Kit; group 4, autoclaved and treated with Shofu Brownie and Greenie polishing points; and group 5, autoclaved and treated with a standard rubber prophylaxis cup. The curing tips were packaged and subjected to 30 autoclave cycles in a clinical autoclave with standard loads of clinical instruments. The light transmission was measured with a curing radiometer. RESULTS: Results showed a 7% decrease in energy transmission for the untreated tips compared to the control. Both polishing system groups demonstrated a 4% decrease. There was no significant difference between the control and the first three groups. The polishing point and prophylaxis cup groups showed significantly decreased energy transmission (decreases of 11% and 25%, respectively). CONCLUSION: Light-curing tips can be autoclaved with routine packaged loads of clinical instruments and retain their ability to transmit light energy, provided that the tips are packaged and the autoclave is properly maintained and filled with distilled water. Commercially available optics maintenance kits are effective in removing deposits and restoring light energy transmission.

Shear bond strengths of six bonding systems using the pushout method of in vitro testing.

The newest generation of bonding systems consolidates multiple components into fewer containers in order to simplify clinical procedures and save clinicians time. Six newer adhesive systems (Scotchbond Multi-Purpose Plus, PROBOND, OptiBond FL, Prime & Bond, One Step, and Tenure Quik) were tested for in vitro shear bond strength (SBS) of a hybrid composite to both superficial and deep dentin at 24 hours and 6 months employing a pushout test method. Results showed significant differences in SBS between superficial and deep dentin for both 1-day and 6-month values for all adhesive systems except Tenure Quik. The SBS of OptiBond FL increased significantly for both superficial and deep dentin after 6 months' storage in 37 degrees C water. None of the other adhesive systems showed a significant change in SBS at 6 months. There appear to be several advantages to the testing method.

Composite bonding to dentin and enamel: effect of humidity.

The effect of oral ambient air on shear strength to etched enamel and dentin was determined for OptiBond FL (Kerr Corp., Orange, CA) and Prodigy resin composite (Kerr Corp.). Enamel and dentin specimens of extracted human teeth were treated both in a dry environment and after exposure to oral humidity according to manufacturer's instructions. Shear strengths of this system are 22.6 MPa for etched, dry enamel; 22.2 MPa for etched, wet enamel; and 18.4 MPa for etched, dry or wet dentin. Differences in shear strengths between the wet and dry enamel or the wet and dry dentin were not significant. Multiple Student's t-tests were used for statistical analysis. Fracture modes for all specimens were examined under a stereomicroscope. Within the parameters of this in vitro study, OptiBond FL was not affected by oral humidity.

Effects of uncontrolled outdoor storage on the polymerization, manipulation, and appearance of visible light-cured composite resin and resin-modified glass ionomer materials.

Four light-cured composite resins (Z100, Heliomolar RO, Herculite XRV, and Prisma APH) and two resin-modified glass ionomer restorative materials (Fuji II LC and VariGlas VLC) were placed in an uncooled, unheated outdoor storage shed for 12 months. Maximum and minimum ambient temperatures were recorded every 24 hours. Each month, samples were polymerized with a visible light source and alterations in polymerization were assessed using a scratch test. Problems with manipulation or changes in appearance were also monitored. Samples stored outdoors were compared to control samples maintained at room temperature [68-74 degrees F (20-23.3 degrees C)]. Results showed that polymerization of all materials tested was apparently unaffected to any significant clinical degree by outdoor storage at temperatures ranging from 20 to 112 degrees F (-6.6-44.4 degrees C) over 12 months. Eight months into the study, the VariGlas VLC liquid had separated into a viscous gel and watery component. None of the other remaining materials demonstrated any changes in manipulation or appearance. All materials tested except VariGlas VLC appear suitable for use during military deployment or field training exercises under similar environmental conditions.

Liver transplantation: dentistry is an essential part of the team.

Liver transplantation has become a commonplace procedure, with more than 3,000 livers being transplanted annually. Patient demand remains much greater than availability of donor organs, resulting in many deaths per year. Due to the nature of hepatic function, unique concern exists regarding susceptibility to infection and rejection during the post-transplant period, placing great importance on vigilant oral health maintenance. Patients are severely immunocompromised and must be well educated and treated pretransplant and for the rest of their post-transplant lives; however, even though patients are on waiting lists for matching donor livers for an adequate amount of time to provide definitive dental treatment, this is not a major priority on the protocols of some transplant centers. This paper addresses these concerns and illustrates a patient who presented shortly post-transplant with severe dental problems requiring immediate definitive treatment. As these patients may present in any office, general dentists should be aware of the unique concerns involving their assessment, education, treatment and maintenance.

Shear bond strength of composite resin to microetched metal with five newer-generation bonding agents.

The purpose of this study was to determine the shear bond strength of a hybrid composite resin to a nickel-chrome-beryllium (Ni-Cr-Be) alloy, using five of the newer-generation bonding agents: Optibond, All-Bond 2, Prisma Universal Bond 3, Restobond 4, and Amalgambond Plus with HPA. For each bonding system 10 samples of metal were microetched with 50-micron aluminum oxide prior to the placement of the bonding agent and resin. The shear bond strength was tested, and the results showed that Amalgambond Plus with HPA developed the strongest bond at 18.81 +/- 3.924 MPa, followed by All-Bond 2 at 14.33 +/- 3.408, Optibond at 13.97 +/- 1.508, Prisma Universal Bond 3 at 12.51 +/- 1.845, and Restobond 4 at 10.29 +/- 1.407.

In vitro comparison of filled and unfilled universal bonding agents of amalgam to dentin.

In this study, four different adhesive amalgam systems were compared(Amalgambond Plus, Amalgambond Plus with HPA, All-Bond 2, and All-Bond 2 with Liner-F) regarding their ability to bond amalgam to freshly prepared dentinal surfaces. The two groups that yielded the highest mean bond strengths, Amalgambond Plus with HPA and All-Bond 2 with Liner-F, were the only two groups in comparison that were not statistically different (P > 0.05). The use of the filled resin bonding agents created significantly higher bond strengths between tooth and freshly triturated amalgam than the unfilled resin bonding agents. Further study is required to determine: a) the exact nature and mechanism of the bonds, and b) clinical in vivo presence and longevity of the bonds.

Practical infection control in dental laboratories.

Regardless of the dental laboratory infection control methods that are used, excellent communication and cooperation between laboratory staff members and clients must be maintained. The safety of patients is assured only through confidence that dentists and dental technicians use the proper procedures correctly. Whenever a question exists about possible contamination of an item that is brought into the laboratory, the item should be treated as contaminated until processed by prescribed methods.

Laboratory contamination of dental prostheses.

Potential pathogenic microbiologic cross-contamination from various sources by way of the dental laboratory has been documented, and guidelines to reduce it have been published. Ten sterile, complete dentures were fractured and sent to different dental laboratories for repair. Upon return, nine were found to be contaminated with potentially pathogenic microorganisms, possibly from other patients. Dentists must ensure that the possibility of infection to patients from prosthodontic treatment does not exist.