Effect of an 8.0% arginine and calcium carbonate desensitizing toothpaste on shear dentin bond strength.

OBJECTIVE: The objective of this study was to determine the effect of an 8.0% arginine and calcium carbonate desensitizing toothpaste (Colgate Sensitive Pro-Relief) on shear bond strength of composites to bovine incisor dentin. METHODS: Bovine incisors were sectioned and prepared into 27 dentin specimens. The experimental group had 13 specimens treated for 10 sessions of two-minute brushing with an 8.0% arginine and calcium carbonate desensitizing toothpaste, followed by a 30-second agitated water wash. The control group had 14 specimens treated with flour of pumice only. Each specimen was dried, etched with 35% phosphoric acid for 15 seconds, and washed clean. A bonding agent was applied and polymerized. A 2.38 mm diameter column of Filtek Supreme A2 was bonded to the surface and polymerized as per manufacturer's instructions. Specimens were stored in water for at least 48 hours, subjected to a shear force at a crosshead speed of 0.5 mm/minute on an Instron mechanical testing device, and force at failure was recorded. A one-sided t-test was used to evaluate significant differences among the groups as measured by mean shear strength. RESULTS: Mean shear force was 19.6 +/- 9.4 (SD) for the experimental group and 15.4 +/- 6.0 for the control group with p = 0.0291. CONCLUSION: No significant differences were found for bond strength to dentin treated with an 8.0% arginine and calcium carbonate desensitizing toothpaste or pumice. Dentists can still achieve optimal dentin bonding results if a patient is using Colgate Sensitive Pro-Relief to manage dentin hypersensitivity.

Microleakage of Class V restorations using two different compomer systems: an in vitro study.

This study compared the marginal microleakage of Class V cavities restored with Dyract-AP and F2000. Forty Class V cavity preparations were performed on extracted human teeth. As a negative control, twenty teeth were used without Class V preparations. The apical foramina of the teeth were sealed with a layer of varnish and amalgam restorations. Class V cavity preparations with occlusal margins in enamel, and gingival margins in cementum or dentin that measured approximately three millimeters in width (gingival-occlusal) and length (mesial-distal), were prepared on the buccal surface of the teeth. Samples were divided randomly into 2 groups of 15, and restored per manufacturer's instructions using experimental primer/conditioner (PCC, D/C) and Single Bond Adhesive (3M). All restorations were polished with an abrasive finishing kit. After storage in 37 degrees C water for 24 hours, all specimens were thermocycled between 5 degrees C and 55 degrees C for 500 cycles with a 30-second dwell time, followed by immersion in 0.2% basic fucsine for 24 hours. Teeth were then embedded in cold cure acrylic resin, sectioned longitudinally, and the dye penetration at the enamel and cementum margins were scored at 30x magnification. Evaluations were rated from 0 to 3 (0 = no leakage; 1 = dye penetration up to one-half of the preparation depth; 2 = dye penetration more than one-half preparation depth, but less than the axial wall; 3 = dye penetration along the axial wall). Both F-2000 and Dyract-AP indicated no leakage in the enamel margins. Dyract-AP showed no leakage at either the enamel or dentin margins. Fisher's Exact Test revealed that this difference in dentin margins was statistically significant (p < 0.05). Under the given conditions, Dyract-AP and F-2000 demonstrated resistance to microleakage in enamel, and showed Dyract-AP to be more resistant to microleakage in dentin than F-2000.

A stress-releasing intracoronal attachment for extension base removable partial dentures.

Intracoronal retainer systems incorporated into splinted abutment restorations help force distribution. The additional torque introduced by the extension-based removable partial denture is applied over multiple abutments rather than to single abutment teeth. A fixed-removable prosthesis is proposed as a solution to this situation. The Thompson dowel nonlocking semiprecision attachment system is the intracoronal retainer of choice for distal extension denture bases. It allows controlled rotation or stress relief of the removable component by minimizing detrimental transfer of traumatic forces to the abutment teeth. The design and fabrication of the manufactured version of this retainer system is described.

Provisional and definitive prostheses following sinus lift and augmentation procedures.

Sinus lift and augmentation procedures with simultaneous insertion of cylindrical root form implants can be used to treat the atrophic posterior maxilla. The long-term use of a second stage provisional prosthesis is emphasized. The recommended metal-reinforced acrylic resin provisional restoration allows treatment and/or removal of a failing implant and progressive loading before fabrication of the definitive prosthesis. Modifications in prosthesis fabrication after sinus lift surgery and augmentation procedures are discussed.

First-stage fixed provisional restorations for implant prosthodontics.

Combination metal-and-acrylic-resin fixed provisional prostheses can be used in implant dentistry as an alternative to a removable provisional prosthesis. They may be fabricated in the laboratory and inserted on the day of fixture placement to ensure that the patients may return to their normal lifestyles with minimal discomfort or interruption in function and esthetics. These interim restorations may be used in free-standing as well as hybrid types of implant supported prostheses. The materials used and techniques of fabrication are described.

Characterization of wear of tungsten carbide burs.

On the basis of this study, the following conclusions can be made:--Although the primary cause of the diminution of cutting efficiency when composite restorations are cut is due to abrasion, a secondary cause is the adhesion of the melted resin to the flutes.--Amalgams and tooth structures cause significantly less wear to burs than composite restorations.--The design of burs currently used is probably a poor choice to remove composite restorations.