Quintessence International, 09/1994

A case is described in which delayed implants were inserted after the creation of a suitable volume of maxillary crest bone. The procedure used osseointegrated implants, expanded polytetrafluoroethylene membranes, and demineralized bone.

Polymerization of three composite resins was evaluated after they were light cured through one of four different reflective wedges. Other experimental variables were activation times and light units used. The same conditions were used for a control group, in which photoactivation was performed directly on the test specimens. Complete polymerization was never achieved when the curing light was directed through reflective wedges.

Fluoride release from three glass-ionomer cements and one cermet was measured over 1 year and compared. All the materials released fluoride in a similar pattern for the study's duration. The fluoride release was greatest on the fir st day, decreased sharply the second day, and gradually diminished. After 1 year, all specimens released daily fluoride concentrations above 0.5 ppm, reaching as much as 7 ppm. Low powder-liquid ratios always lead to more fluoride release than high ratios.

The outcome of the prosthodontic phase of implant tratment is affected by the position of implant fixtures within the dental supporting tissues; therefore, surgical guides are often used to facilitate ideal fixture placement. This article describes the fabrication and modification of a wax replica of the patient's existing prosthesis, which is converted into a surgical guide. This approach permits accurate fixture placement relative to planned tooth positions in the implant-supported prosthesis, without the need to fabricate a new conventional denture prior to surger

This study evaluated the accuracy of occlusal contacts relative to the mode in which casts are mounted. Specifically, the direct effect on occlusal contacts was assessed with respect to: (a) the type of mounting stone used; (b) the amount of material used realtive to the distance between the mounting plate and the cast base; and (c) the prsence or absence of a restriction of the articulator's vertical opening. A 3 x 2 x 2 factorial analysis of variance and a Dunn's Multiple Comparison Procedure (P .05) showed that one of the three mounting stones was statistically significantly less accurate in reproducing occlusal contacts when a distance of 19 mm existed between the cast and the articulator, regardless of the existance of articulator restriction.

Recently several new bonding agents that show promising in vitro performance have been marketed. Frequently there is inconsistency between in vitro test results and in vivo performance of new adhesive materials. This investigation was designed to evaluate the micromorphologic relationship between in vivo and in vitro dentin after application of two new dentinal bonding systems. V-shaped cavities were restored in vitro and in vivo with Gluma 2000 bonding system a nd Pekafill composite resin and Scotchbond Multi-Purpose bonding system and Z100 composite resin. After dissolution of dental structures, the restorations were observed with scanning electron microscope. No morphologic differences were found between in vivo and in vitro specimens of eithe rdentinal adhesive system. Intertubular and peritubular dentin was reproduced accurately in every specimen.

Recently many researchers have become interested in the adhesion of composite resin to the dentinal surface. Because it is easier to obtain good composite resin adhesion when a surface is free from smear plug, several chemical agents (acids or linking agents) have been suggested for surface preparation. Nevertheless, the pretreatment of dentin leads to an increase of pulpal outflow, which can interfere with the bonding agent's adhesion. Thus, new-generation deninal bonding agents appeared on the market. They use a pool of highly absorbent primers to facilitate the scattering of the agent in the dentin substratum under humid conditions. The present study shows the results, obtained with the help of scanning electron microscopy, of resinous penetration into the tubular structures of dentin using a latest-generation bonding system. The in vivo and in vitro tests showed a deep scattering of intermediate fluid resin into tubules, even in the presence of physiologic outlfow of dentinal flui

The technique of using a light-hardening glass-ionomer-resin cement restorative material and a stainless steel round wire as a long-term retentive space maintainer following the uprighting of mandibular molars is introduced through the report of a clinical case. The technique is modified for incorporation into provisional crylic resin restorations as a short-term retentive space maintainer in the time interval between the impression and the cementation of the fixed partial denture.

A questionnaire was mailed to 3,000 practicing dentists to inquire about their physical and psychological responses to the task of administering local anesthesia. Surprisingly, 18.8% of the 711 responding dentists reported that the administration of injections causes them enough distress to have (at least at some time) reconsidered dentistry as a career. Six percent of respondents considered their thoughts and feelings to be a serious problem, whereas only 2% reported no negative reaction s to this aspect of clinical practice. Self-reported reactions to various anesthetic procedures were compared, and the various respones are discussed. It is concluded that the administration of anesthetic injections is ararely discussed but significant contributor to the overall professional stress and difficulty for many, but not all, dentists

This study was made to assess whether the physical structure or the commercial make of a glove has any influence on the penetration of liquid through perforations in the glove during work. A comparison was made between three types of gloves (10 for each brand name and type): vinyl (Peha Fit, Paul Hartmann), latex (without ASTM certification), and Biogel D (Regent Dental Division) for a total of 30 gloves. Of the 10 gloves for each type, five were worn tightly adhering to the operator's hand and five were worn relatively loosely. Holes of a predetermined size (.040 mm) were made in each glove on the index, middle, and ring fingers, for a total of 90 holes. A randomized preprogrammed list ensured a perfect balance of the three variables: type of glove, adherence to the hand, and fingers having holes. The amount of liquid that penetrated the gloves through the holes was determined by placing the gloved hand in a tank containing a colored substance for 3 minutes and then analyzing the colored substance that had penetrated the glove with an ultraviolet (UV) spectophotometer. The results clearly showed that the amount of liquid that penetrated through the holes varied significantly (p 0.001) according to the type of glove tested. The mean quantity of liquid penetrating the vinyl gloves (6.24 uL) was approximately five times higher than that of the latex gloves (1.20 uL), and 100 times higher than that of the Biogel D gloves (0.05 uL). The statistical differences between the three types of gloves were even more significant in the cases in which the glove adhered closely to the hand (12.44 uL in vinyl, 2.37 uL in latex, and 0.09 uL in Biogel D), whereas no significant difference was found when the gloves were loose (0.03 uL in vinyl, 0.04 in latex, and 0.00 uL in Biogel D).