Experimental impression tray fabricated with a NiTi shape memory alloy plate.
A small experimental impression tray was fabricated with a NiTi shape memory alloy plate. After recovery of the shape memory effect, the upper rims of the tray holding the impression were opened to some extent, the resistance during removal of the model from the impression was significantly decreased compared to a commercially available tray and the tray before recovery of the shape memory effect. The pull-out force of the model from the impression was 23.5(0.2)N for the commercially available tray, 23.5(3.9)N for the experimental tray before recovery of the shape memory effect and 14.7(4.0)N after recovery of the shape memory effect (heated for 15 min at 70 degrees C). Therefore the tray should be useful in teeth fracture free modeling. (+info)
A survey of the delegation of orthodontic tasks and the training of chairside support staff in 22 European countries.
This paper reports on a survey which was undertaken to investigate the delegation of orthodontic tasks and the training of chairside support staff in Europe. Two questionnaires were posted to all members of the EURO-QUAL BIOMED II project together with an explanatory letter. The first dealt with the delegation of nine clinical tasks during orthodontic treatment. The second with the types of chairside assistant employed in each country and the training that they are given. Completed questionnaires, which were subsequently validated, were returned by orthodontists from 22 countries. They indicated that there was no delegation of clinical tasks in six of the 22 countries and delegation of all nine tasks in five countries. The most commonly delegated tasks were taking radiographs (in 14 of the 22 countries) and taking impressions (in 13 of the 22 countries). The least commonly delegated tasks were cementing bands (in five of the 22 countries) and trying on bands (in six of the 22 countries). Seven of the 22 countries provided chairside assistants with training in some clinical orthodontic tasks. Eighteen of the 22 countries provided general training for chairside assistants and offered a qualification for chairside assistants. Four of these 18 countries reported that they only employed qualified chairside assistants. Of the four countries which reported that they did not provide a qualification for chairside assistants, two indicated that they employed chairside assistants with no formal training and two that they did not employ chairside assistants. It was concluded that there were wide variations within Europe as far as the training and employment of chairside assistants, with or without formal qualifications, and in the delegation of clinical orthodontic tasks to auxiliaries was concerned. (+info)
The use of specific dental school-taught restorative techniques by practicing clinicians.
In 1995, a survey requesting information about the utilization of certain prosthodontic techniques was mailed to 3,544 graduates of a midwestern dental school. Responses were received from 1,455 alumni, representing a 41 percent return rate. In general, the results are consistent with international and national trends and show significant disparity in the utilization rates of certain procedures between general dentists and prosthodontists, as well as a disconnect between what is taught in the undergraduate dental educational program and what is applied in practice. For example, while prosthodontists typically apply what was taught in their educational program, utilization rates of general dentists for the facebow was 29.64 percent; the custom tray 68.48 percent; border molding 58.67 percent; altered casts 24.10 percent; custom posts 49.29 percent; prefabricated posts 67.54 percent; and semi-adjustable articulators 50.64 percent. While no solutions to this disconnect are offered the authors do pose important questions that must be addressed by the dental educational community. (+info)
The relationship between odontogenic bacteraemia and orthodontic treatment procedures.
The purpose of this research was to estimate the prevalence and intensity of bacteraemia associated with orthodontic treatment procedures. The four procedures investigated were: an upper alginate impression, separator placement, band placement, and adjustment of an archwire on a fixed appliance. Eighty-one children undergoing general anaesthesia (GA) for dento-alveolar surgery related to their orthodontic treatment were randomly allocated to the impression or separator group. A further 61 children, receiving treatment in the Outpatient Department, were included and randomly allocated to the banding or archwire adjustment groups. A cannula was inserted into either the left or right antecubital fossa using an aseptic technique. A baseline 6 ml sample of blood was taken before treatment and a second 6 ml sample was taken 30 seconds after the procedure. There was no significant difference in the number of positive blood cultures between baseline (nine, 23 per cent), and following an upper alginate impression (twelve, 31 per cent); between baseline (twelve, 27 per cent), and placement of a separator (fifteen, 36 per cent); between baseline (nine, 36 per cent), and fitting or placement of a band (eleven, 44 per cent); or between baseline (twelve, 33 per cent), and archwire adjustment (seven, 19.4 per cent). For the separator group only the mean total number of aerobic and anaerobic bacteria combined, isolated from the blood samples (cfu of bacteria per ml of blood), was significantly greater following the placement of a separator (2.2, SD 9.1), compared with baseline (0.9, SD 0.2; P < 0.02). This investigation demonstrates that the only orthodontic treatment procedure that causes a significant bacteraemia is the placement of a separator. (+info)
Crowns and other extra-coronal restorations: resin-bonded metal restorations.
Resin-bonded metal restorations is the final part of the series. Cast metal restorations which rely on adhesion for attachment to teeth are attractive because of their potential to be much more conservative of tooth structure than conventional crowns which rely on preparation features providing macromechanical resistance and retention. (+info)
Two-implant mandibular overdentures: simple to fabricate and easy to wear.
Success rates for titanium dental implants in the anterior mandible are very high. Because of these success rates, as well as lower costs, it is common to treat edentulous patients with just 2 implants and ball anchors for retention of the overdenture, instead of 4 implants and a bar. In this paper the fabrication of 2-implant overdentures is described. In a controlled clinical trial (to be reported elsewhere), 30 subjects received a 2-implant overdenture for the mandible and a conventional prosthesis for the maxilla. The 30 control patients received conventional complete dentures for both jaws. The stability of the overdentures was excellent, and the lingual dimensions of the denture could be reduced to the level of the mylohyoid line to provide more space for the tongue. In patients with tense labial musculature or a limited amount of attached gingiva, it was important to elevate the shoulder of the implant and ball abutment above the gingival level to avoid peri-implant problems. Significantly fewer visits for adjustment related to post-placement pressure spots were required for mandibular overdentures than for conventional mandibular prostheses. (+info)
A modified impression technique for accurate registration of peri-implant soft tissues.
Replacement of single missing teeth with an implant-supported restoration is recognized as a highly successful treatment. An impression technique for peri-implant soft-tissue replication in an anterior zone is described. The technique involves use of an interim restoration as an abutment for the final impression. This allows accurate duplication of the soft tissues and fabrication of a final restoration with the correct emergence profile. (+info)
The aim of this paper is to familiarize the readers with some of the clinical considerations necessary to ensure successful use of mid-palatal implants. Both surgical and technical aspects will be discussed along with a description of impression techniques used. (+info)