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Using double-poured alginate impressions to fabricate bleaching trays.

Esthetic and diagnostic treatment often requires two casts of one arch, one for baseline and one for alterations (diagnostic wax-up, bleaching tray, occlusal analysis). The purpose of this study was to compare the accuracy of stone casts generated from a second pour of a properly handled alginate impression with first-poured casts. A maxillary dentoform was indexed with six reference spaces (#8-15, 9-2, 2-15, and incisal-to-gingival of #3, 9, 14). Irreversible hydrocolloid (Jeltrate) impressions were made in perforated steel trays by a single investigator. Impression material was spatulated for 1 minute. The seated impression and dentoform were wrapped in a damp paper towel to simulate intraoral conditions, and allowed to set for 2 minutes. Upon separation, the impression was stored in a damp towel for 5 minutes. The impression was poured in cast stone (Microstone) according to the manufacturer's instructions. The stone-filled impression was immediately rewrapped in a damp paper towel and allowed to set for 45 minutes at room temperature. Upon removal of the stone, the impression was rinsed with cold water, shaken dry, and repoured in the same manner. Ten impressions were made: the first five impressions were poured to make casts for Group A, then repoured as described above for casts for Group B. The remaining five impressions were poured once to make casts for Group C. The six spaces of each cast were measured three times in random order using a dial caliper and the space average calculated for the cast. At each space, analysis of variance showed no significant difference among Groups A, B, or C (P < 0.05). When alginate impressions that have been poured with cast stone are kept moist during stone setting and repoured within 45 minutes, two casts can be generated from one impression with the same degree of accuracy as two casts made from taking two separate impressions, providing the alginate does not tear during first cast removal.

Alginates↗

Simplified guide for precise implant placement: a technical note.

Ideal implant placement is ultimately determined by the requirements of the final restoration. For the surgeon placing implants, proper angulation, parallelism, and spacing are critical to the final restoration. The use of a stainless-steel drill guide sleeve in an acrylic resin surgical template can make it possible to achieve optimal placement. Communication between the restoring dentist, surgeon, and laboratory technician is enhanced by this system since dowel pins fit precisely into the sleeves and determine sleeve and, ultimately, implant position. This system allows the surgeon to negotiate bony irregularities and ramping defects with ease while preparing a more concentric implant site.

Dental Equipment↗

Human experimental caries models: intra-oral environmental variability.

In situ caries models serve purposes other than just being a simpler way to obtain data than running a clinical trial. However, variation in information obtained not only among individuals but also, in particular, depending on different locations of the models within the oral cavity have so far been given little attention. In the present review, the aim has been to characterize the different designs of in situ caries models and to describe some important factors which may vary within the oral cavity and thus influence the outcome of the way the different in situ models are used. Advantages and disadvantages of in vivo models vs. in situ models are discussed. In the latter case, the distinction is made between dental appliance models and so-called "single tooth" models. The review concludes that in situ models differ distinctly with regard to their "biological potential". Because of regional differences in salivary film velocity, pH, and composition of the microflora, results obtained by the various models are not likely to be immediately comparable. Moreover, local factors in relation to specimen environment, such as degree of "protection" and plaque thickness, may further add to the differences. It is suggested that these observations are important in considerations of the relevance of substituting clinical trials with in situ studies. Because of the pronounced intra-oral variation in certain parameters thought to be important for caries lesion development, we conclude that no in situ model can, by itself, fulfill the role as the "model of choice". Finally, although in situ models are useful adjuncts in attempts to estimate the relative effects of new anticaries methods or compounds on caries initiation, the selection of in situ study model design will strongly depend on the aim and purpose of the study.

Dental Caries↗

An evaluation of in vivo desensitization and video modeling to increase compliance with dental procedures in persons with mental retardation.

Fear of dental procedures deters many individuals with mental retardation from accepting dental treatment. This study was conducted to assess the effectiveness of two procedures, in vivo desensitization and video modeling, for increasing compliance with dental procedures in participants with severe or profound mental retardation. Desensitization increased compliance for all 5 participants, whereas video modeling increased compliance for only 1 of 3 participants.

Adult↗

The use of a modelling technique to investigate the root canal morphology of mandibular incisors.

The prime objective of this study was to develop and test a method of modelling the dental root canal system using a vinyl resin, type UCAR-VYHD. It also aimed to verify if the resin models allow a three-dimensional evaluation of those features of the pulpal morphology of human permanent mandibular incisor teeth, which might be associated with periodontal disease. One hundred and eleven freshly extracted teeth were studied. Pre-extraction clinical records and periapical radiographs were used to deduce the presence or absence of periodontal disease. Each extracted tooth was radiographed in two perpendicular planes before being opened by conventional orthograde endodontic technique, and photographed in a scanning electron microscope. The patent pulp space was then obturated with the vinyl resin. Scanning electron photomicrographs of the resin replicas and of the teeth were compared with the earlier radiographic images to correlate the morphological findings. The numbers of root canals and apical foramina were recorded. This study showed that in mandibular incisors with periodontal disease there was a relatively low incidence of lateral canals (7.2%). The modelling technique was found to be reliable, reproducible, and provided sufficient detail to allow three-dimensional analysis of root canal morphology.

Adult↗

Pretreatment modeling. A technique for reducing children's fear in the dental operatory.

Research on modeling indicates that this technique offers dentists a means of reducing fear in child patients of all ages. As a preventive measure used with children who have had no prior exposure to dental treatment, it can be particularly efficacious. Based on the assumption that much of adult dental avoidance is based on dental fears acquired in childhood treatment, the reduction of children's dental fear would have a positive effect on the individual's tendency to seek out dental health care throughout his or her lifespan. For the dentist, there are also short- and long-term benefits. Dental management of the child is prerequisite to providing good dental care. Pedodontics as a specialty recognizes behavioral management of the child cannot be separated from the quality of the dentist's work. Fear has been identified as an important factor in disruptive behavior of school age children in the dental office. Practicing dentists consider the fearful, disruptive child to be among the most troublesome of problems in their clinical work. The child must cooperate or at least passively comply with the dentist's procedures in order to have the technical work completed. By reducing disruptive patient behavior (crying, screaming children whose peripheral and gross motor movements often make direct contact with the dentist or his equipment) the most unpalatable aspect of pediatric dentistry is minimized. Further, the actual time for treatment becomes shorter rather than longer. Although modeling is not restricted to videotape media, the emergence of current videotape technology provides the practitioner with the means for incorporating patient viewing of prerecorded modeling tapes as part of the usual waiting period. Such a procedure would mean that in the long run, the dentist will spend more time doing dentistry and less in behavioral management tasks.

Anxiety↗