The Influence of Nitrile Gloves on the Setting Behavior of Polyvinyl Siloxane Putty Impression Materials.

OBJECTIVE: The purpose of this study was to assess the gelation and polymerization time of three polyvinyl siloxane (PVS) putty materials and to determine if those times were affected by nitrile gloves under different conditions. MATERIALS AND METHODS: Ten specimens (n=10) were obtained for each PVS putty material (Express STD, 3M ESPE; Extrude Xtra, Kerr and Exafast, GC) and tested under different conditions (gloves washed, gloves unwashed and hands contaminated). The gelation and polymerization time were measured using an oscillating rheometer and recorded for 400 s at 37°C to simulate the oral environment. RESULTS: The mean gelation time of hand contaminated specimens was 157.50 minutes and was significantly slower than that by using nitrile washed gloves (mean=117.94, p=.004) and by using unwashed gloves (mean=99.46, p⟨0.001). Unwashed gloves had significantly quicker gelation times compared to washed gloves (p=.046). The gelation time was significantly delayed with Exafast compared to Extrude Xtra and Express STD across all the different types of glove conditions (p⟨0.043). No significant differences were observed between polymerization time with Exafast and Extrude Xtra Putty. CONCLUSIONS: Extrude Xtra putty material had significantly better performance than GC Exafast and Express. Hand contaminated specimens were affected by the gelation/polymerization time.

In Vitro Wear of Glass-Ionomer Containing Restorative Materials.

STATEMENT OF PROBLEM: Advertisements of glass-ionomer-containing restorative materials recommend suitability as load-bearing permanent or semi-permanent restorations. Historically, unacceptably high wear rates limit clinical indications of glass-ionomer-containing restorations in this regard. OBJECTIVE: To compare the in vitro wear of contemporary glass-ionomer-containing dental materials commercially advertised for use in permanent dentition as load-bearing restorations in a chewing simulator. Resin composite was tested as a control. METHODS AND MATERIALS: A resin-modified glass ionomer (Ionolux, VOCO gmbH), a high viscosity glass-ionomer hybrid system (Equia Forte HT with Equia Coat, GC America), and a bioactive ionic resin with reactive glass filler (Activa Bioactive Restorative, Pulpdent) were evaluated. Filtek Supreme Ultra (3M ESPE) is a visible light-activated resin composite that served as a control. Standardized flat disk-shaped specimens (n=12/group) were submitted to 500,000 cycles with continuous thermal cycling against steatite antagonists. Volumetric wear was measured at 1000, 10,000, 200,000, and 500,000 cycles. RESULTS: There was a statistically significant difference in mean volumetric wear for Activa Bioactive Restorative (p=0.0081, 95% CI: 0.3973, 0.4982) and Equia Forte HT (p<0.001, 95% CI: 1.2495, 1.8493), but no statistically significant difference in mean volumetric wear for Ionolux (p=0.6653) compared to control. Activa Bioactive Restorative wore approximately 60% less than, and Equia Forte HT twice more than Filtek Supreme Ultra on average, respectively. CONCLUSIONS: Compared to a resin composite, contemporary glass-ionomer-containing restorative materials advertised for use as load-bearing restorations display measurably variable in vitro wear rates.

Effect of Preheating and Fatiguing on Mechanical Properties of Bulk-fill and Conventional Composite Resin.

CLINICAL RELEVANCE: Bulk-fill composite resins may have comparable mechanical properties to conventional composite resin. Preheating does not reduce the mechanical properties of composite resins.

Effect of Resin-modified Glass Ionomer Cement Dispensing/Mixing Methods on Mechanical Properties.

STATEMENT OF THE PROBLEM: Resin-modified glass ionomer cements (RMGIs) are often used for luting indirect restorations. Hand-mixing traditional cements demands significant time and may be technique sensitive. Efforts have been made by manufacturers to introduce the same cement using different dispensing/mixing methods. It is not known what effects these changes may have on the mechanical properties of the dental cement. PURPOSE: The purpose of this study was to evaluate the mechanical properties (diametral tensile strength [DTS], compressive strength [CS], and fracture toughness [FT]) of RMGIs with different dispensing/mixing systems. METHODS AND MATERIALS: The RMGI specimens (n=14)-RelyX Luting (hand mix), RelyX Luting Plus (clicker-hand mix), RelyX Luting Plus (automix) (3M ESPE), GC Fuji PLUS (capsule-automix), and GC FujiCEM 2 (automix) (GC)-were prepared for each mechanical test and examined after thermocycling (n=7/subgroup) for 20,000 cycles to the following: DTS, CS (ISO 9917-1) and FT (ISO standard 6872; Single-edge V-notched beam method). Specimens were mounted and loaded with a universal testing machine until failure occurred. Two-/one-way analysis of variance followed by Tukey honestly significantly different post hoc test was used to analyze data for statistical significance ( p<0.05). RESULTS: The interaction effect of both dispensing/mixing method and thermocycling was significant only for the CS test of the GC group ( p<0.05). The different dispensing/mixing methods had no effect on the DTS of the tested cements. The CS of GC Fuji PLUS was significantly higher than that of the automix version ( p<0.05). The FT decreased significantly when switching from RelyX (hand mix) to RelyX Luting Plus (clicker-hand mix) and to RelyX Luting Plus (automix) ( p<0.05). Except in the case of the DTS of the GC group and the CS of GC Fuji PLUS, thermocycling had a significant effect reducing the mechanical properties of the RMGI cements ( p<0.05). CONCLUSIONS: Introducing alternative dispensing/mixing methods for mixing RMGIs to reduce time and technique sensitivity may affect mechanical properties and is brand dependent.

Conservative indirect restorations for posterior teeth. Cast versus bonded ceramic.

The practitioner today has a number of alternative restorative modalities from which to chose when faced with the necessity of restoring posterior teeth. The primary options with extensively broken down posterior teeth are cast gold and bonded ceramic inlays, onlays, and partial veneer restorations. The dentist and informed patient should make the choice of which modality is appropriate based on a number of criteria. Certainly, based on the criteria of basic physical properties, potential for marginal integrity and stability of that integrity, cast gold is the material of choice. In terms of conservation of tooth structure and systemic biocompatibility, both restoration types are excellent. With regard to effects on long-term pulpal health, much remains unknown with many of the materials used with bonded restorations at the present time. Conservative cast gold restorations have proved to be very successful in this regard over the long term. The potential for tooth strengthening with bonded restorations is certainly an exciting, but as yet, unproven, clinical reality. Thus, until those clinical data are available, the most predictable means of restoration of extensively broken down posterior teeth is with partial-coverage cast gold, protecting cusps at risk as required (Fig. 9). As mentioned previously, cast gold inlays are also a very conservative and predictable restoration (Fig. 10). Both cast gold and bonded ceramic restorations are technically demanding, but the details required to produce excellent gold castings are well defined, and can be learned readily. Much remains to be learned regarding the materials and the techniques used to fabricate bonded ceramic restorations. Priority issues would seem to be reaching a consensus regarding the details of tooth preparation and the development of improved luting resins with improved wear resistance. Simplified techniques to improve the quality of the fit of these types of restoration also are of paramount importance. The requirement for an esthetic, or, more properly, use of a tooth-colored restoration in a posterior tooth, should be evaluated carefully for each individual restoration. Often it is possible to restore a tooth with cast gold with minimal or no display of metal. The patient will then receive the long-term benefit of cast gold and not compromise on esthetics. It is our obligation as diagnosticians to educate our patients so that they are in a position to choose, when indicated, this most cost effective of restorative options.

Treatment planning and soft tissue management for optimal implant aesthetics.

Aesthetic restoration of single anterior teeth is one of the most difficult procedures to execute. This article discusses patient selection criteria, implant position and its relationship to the aesthetic outcome. The importance of soft tissue management in all phases of surgical and restorative phases is emphasized. Guidelines are given for the successful delivery of this service for the patient that will preserve adjacent teeth and fulfill functional and aesthetic needs.

Indirect inhibition of polymerization of a polyvinyl siloxane impression material: a case report.

The inhibition of polymerization of polyvinyl siloxane impression materials by direct contact with latex gloves has been well documented. Indirect intraoral inhibition of polymerization that results from contact of oral tissues with latex gloves during tooth preparation and gingival retraction procedures has been reported. This case report illustrates the problems that can occur when the dentist used polyvinyl siloxane impression materials while wearing latex gloves. In the reported case, the inhibition is severe and obvious; in most situations the inhibition of polymerization is more subtle and is frequently undetected. Clinicians must be aware of this potential problem and the solution to it.

Contemporary evaluation of dental cements.

Today, the clinician has numerous dental cements available for luting of restorations to prepared teeth. Compared to traditional cements, many of the newer cements have improved physical properties. In this article, we analyze available cements in terms of these physical properties based on scientific data and attempts to determine their effect on long-term clinical performance. We conclude that these improved physical properties do not necessarily result in improved clinical performance. We also conclude that although these newer cements have specific clinical applications, they should not be routinely used for the cementation of metal castings because they are clearly more technique-sensitive than traditional luting agents. Zinc-phosphate cement remains the cement of choice for cementing cast gold and metal-ceramic restorations.

Use of radicular attachments with endodontically treated teeth.

An extension of conventional overdenture philosophy with the use of radicular attachments in endodontically treated teeth can be used to improve stability, reduce bony resorption and proprioception and augment retention. However, radicular attachments are not appropriate in all cases. Indications, requirements, advantages and disadvantages of this type of prosthesis are provided.

Endodontically treated teeth: a summary of restorative concerns.

Endodontically treated teeth can be successfully used as abutments to support prostheses, both fixed and removable, if they are properly selected and restored. Selection and restoration criteria are presented.

Soft tissue management with metal-ceramic and all-ceramic restorations.

Many advances have been made in recent years to the science and the art of metal-ceramic and all-ceramic restorations. However, no matter how natural and lifelike such restorations may be, the final esthetic result is most dependent upon the health and level of the surrounding gingival tissues. The key to success is effective soft tissue management, and the goal of this soft tissue management has been to provide healthy gingival tissues covering sound, smooth restorative margins.

The versatile and esthetic metal-ceramic crown.

The predictability, many advantages and remarkable adaptability of metal-ceramic crowns account for their frequent use. Metal-ceramic crowns will continue to be one of the most widely used dental restorations.

Materials for conservative posterior restorations.

Advantages and disadvantages of amalgam and cast gold restorations are compared to those of new tooth-colored restorations. Success can be achieved using many different types, but the benefits of traditional restorations should not be forgotten.

Restoration of an anterior edentulous space.

Removable partial dentures are often overlooked as a restorative option for an anterior edentulous space. This article will focus on the advantages and disadvantages of removable prostheses for the restoration of the anterior edentulous space in specific clinical situations.

Rational use of contemporary all-ceramic crown systems.

There are a host of contemporary all-ceramic systems available today, as well as improved techniques for metal-ceramic restorations. Perhaps the most important factor in achieving predictable success with these restorations is excellent soft tissue management. Metal-ceramic restorations provide the most predictable service in terms of clinical longevity, versatility and prevention of wear to the opposing dentition.

Clinical experiences with bonded porcelain laminate veneers.

Bonded porcelain veneers can provide successful esthetic and functional long-term service for patients. The purpose of this article is to describe the authors' clinical experiences with veneers over the past decade and to outline the procedures required to achieve predictable success with this conservative esthetic restorative modality. It is hoped that the authors' experiences and those of others will encourage practitioners to consider more routine use of this type of restoration in many of their more complex reconstructive cases.