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At least 1,081 records · Page 60Linked to original sources
PubMed1975

The effect of preparation procedures on original canal shape and on apical foramen shape.

With the use of clear casting resin, simulated curved canals were created so that canal preparation procedures could be directly visualized and compared. Regardless of the type of enlarging instrument or the technique used, undesirable characteristics were produced in all preparations that would make canal filling difficult. To modify the typical preparations, alteration of the enlarging flutes, use of rasping rather than rotation of the instruments, and a flaring technique are recommended.

Dental Pulp Cavity↗
PubMed1975

The use of transparent teeth in the teaching of preclinical endodontics.

Demineralized teeth, which were cleared and hardened in xylene, were used in the teaching of preclinical endodontics. The teeth appeared well suited for the purpose. Of 39 students attending the course, 30 students thought that the use of transparent teeth had facilitated the learning of endodontic techniques.

Decalcification Technique↗
PubMed2002

Porosities and voids in Class I restorations placed by six operators using a packable or syringable composite.

OBJECTIVES: The aim of the study was to investigate the influence of two resin composites with different handling properties and application techniques on the homogeneity of a restoration placed in small and large cavities. Furthermore, the operator-effect on the restorative procedure was studied. METHODS: Standardized Class I cavities of two sizes were prepared in artificial lower first molars. The cavities were restored with two resin composites (Surefil and Ecusit) using either a packing or an injection technique. Six operators were involved in the study, five general practitioners and one final-year dental student. Each operator restored 40 preparations, ten in each group. After finishing, the restorations were sectioned and inspected for the presence of voids and porosities. RESULTS: 240 restorations were placed and 480 sections were available for evaluation. Only 143 sections were totally free of porosities. For both the small and large preparation design the Ecusit composite used with the injection technique resulted in significantly less porosities in the restoration. Differences between operators were evident, but none of the operators achieved significantly better results with the packing technique than with the injection technique. SIGNIFICANCE: The use of a syringable resin composite results in a better adaptation of the restoration compared to a packable resin composite.

Composite Resins↗
PubMed1997

A new approach to indirect bonding using light-cure composites.

Indirect bonding offers many advantages over direct bonding. The ability to better visualize teeth for proper bracket placement and reduced chair time leads to a less stressful bonding experience for the orthodontist. Conventional approaches to indirect bonding have relied on transfer trays made of materials that are not transparent. After these trays are placed on teeth, one cannot ensure proper seating of the tray and, because of their opaque nature, the orthodontist must use self-cure composites that are very difficult to remove around the brackets after the tray is removed. A new approach has been proposed in this article, which significantly modifies the fabrication of the indirect bonding transfer tray and provides direct visualization and access to the brackets during both the laboratory and clinical stages of the procedure. Furthermore, the orthodontist may use light-cure composite resins, clean off excess composite around the brackets, and apply light curing when fully satisfied with bracket position and hygiene.

Acrylic Resins↗
PubMed2003

A new removable implant analog.

A new implant analog system that improves the efficiency of the implant restoration's fabrication process is described. This 2-piece analog contains an outer plastic sleeve that is retained within the stone cast. The inner portion, a metal analog, can be easily removed and replaced within the plastic sleeve. Because the metal analog is removable, the time-consuming process of screwing and unscrewing the prosthesis- or abutment-retaining screws during laboratory procedures can be minimized. The prosthesis can remain secured to the analog during waxing, metal finishing, and porcelain buildup, yet is easily removed from the cast for inspection.

Crowns↗
PubMed2000

Predetermined implant positioning by means of a novel guide template technique.

This paper presents a novel guide template technique for implant placement. In esthetic implant dentistry with its restoration-driven implant placement as well as in complete-arch cases with multiple implants, the precise positioning and angulation of dental implants is crucial for achieving the desired prosthetic results. Difficulties in implant positioning may arise especially with grafted jaws resulting from communication problems between surgeon and prosthodontist. This method may alleviate some of the problems common to conventional template techniques, where the drill is usually directly guided by the template. The key idea is to fixate the implant position and angulation by the help of Kirschner wires which are inserted in the alveolar ridge right through the mucosa before elevation of a mucoperiosteal flap. Thanks to this sequence, the template for guiding the wires may be positioned precisely, even on grafted edentulous ridges. After the insertion of the wires, the bone is exposed and the implant cavities prepared with a trephine drill guided over the wires alone or over wires combined with a special guidance cylinder fitting the trephine drill. The method may be combined with different planning and radiological techniques. Since the use of the template is detached from the actual drilling process, the danger of introducing debris of plastic or metal into the preparation site may be avoided. The present technique might be helpful for difficult cases by improving communication between prosthodontist and surgeon and also render additional security to the surgeon with less routine in dental implant insertion.

Dental Implantation, Endosseous↗
PubMed1999

Removable prostheses.

Reconstruction of the dentition extensively damaged through tooth surface loss may require the use of removable prostheses. This can be the most appropriate type of treatment when either the teeth are very severely worn or the patient wishes a simpler and more economical approach than a fixed reconstruction.

Adult↗
PubMed2002

The accuracy of 4 panoramic units in the projection of mesiodistal tooth angulations.

The purpose of this study was to compare the mesiodistal tooth angulations determined with a typodont/skull testing device with the images of mesiodistal tooth angulations from 4 contemporary panoramic units (OP 100, Cranex 3+, Orthophos, PM 2002 EC). A typodont testing device was constructed, and the true mesiodistal tooth angulations relative to an orthodontic archwire were determined with a 3-dimensional coordinate-measuring machine and custom-designed software. A human skull served as the matrix into which the typodont was fixed for imaging. The skull was repeatedly imaged and repositioned 5 times for each panoramic unit. The images were scanned and digitized with custom software to determine the image mesiodistal angulations. Results revealed that the majority of image angles from the 4 panoramic units were statistically significantly different from the true angle measurements. However, definite trends were noted among the panoramic units. For the maxillary teeth, the images projected the anterior roots more mesially and the posterior roots more distally, creating the appearance of exaggerated root divergence between the canine and the first premolar. For the mandibular teeth, the images projected almost all roots more mesially than they really were, with the canine and the first premolar the most severely affected. The largest angular difference for adjacent teeth occurred between the mandibular lateral incisor and the canine, with relative root parallelism projected as root convergence. It was concluded that the clinical assessment of mesiodistal tooth angulation with panoramic radiography should be approached with extreme caution and with an understanding of the inherent image distortions.

Analysis of Variance↗
PubMed2001

Alternative uses of a visible light-polymerized material.

Three different procedures that involve the use of Triad gel are described. This light-polymerized resin material is versatile and easy to use in the dental clinic and laboratory. The procedures described include the transfer of ridge topography for ovate pontic sites, implant lab analog fixation, and solid/soft tissue cast fabrication.

Acrylic Resins↗
PubMed2002

A clinical pilot study of the dimensional accuracy of double-arch and complete-arch impressions.

STATEMENT OF PROBLEM: It has been suggested that articulated casts fabricated with the double-arch impression technique may have superior occlusal accuracy than those fabricated with a single complete-arch impression. However, lack of tray rigidity may lead to flexure of the impression/tray complex, resulting in inaccurate dies in the bucco-lingual dimension. PURPOSE: This clinical pilot study compared the dimensions of dies fabricated with 3 types of double-arch impressions to dies fabricated with the conventional complete-arch, custom tray method. MATERIAL AND METHODS: Thirty-five addition silicone impressions were made of cast metal copings cemented onto natural teeth prepared as complete-crown abutments. Four combinations of tray types and impression material viscosity were used: (1) complete-arch, custom acrylic trays loaded with heavy-bodied material; (2) double-arch, disposable plastic trays loaded with heavy-bodied material; (3) double-arch, disposable plastic trays loaded with putty material; and (4) double-arch, reusable brass metal trays loaded with heavy-bodied material. Immediately prior to tray insertion, light-bodied impression material was syringed over all copings as a wash. The 4 copings were fabricated from cast gold and simulated metal-ceramic complete-crown thimbles with polished collars and had "projections" on the occlusal surfaces. The impressions were poured in type IV die-stone. Bucco-lingual and inter-abutment dimensions were measured. The differences between the stone dimensions and cast metal control dimensions were calculated and converted to percent dimensional change. The data were analyzed with 1-way analysis of variance, Student t tests, and Mann-Whitney tests (P<.05). RESULTS: The plastic double-arch tray loaded with heavy-viscosity addition silicone and a low-viscosity wash produced the least accurate combination inter- and intra-abutment dimensions. For this protocol, 1.17% mean dimensional change was recorded. This result was significantly different than that obtained for the other 3 impression methods tested. No significant differences were found between the complete-arch method and protocols in which putty was loaded in a plastic or metal tray. CONCLUSION: Within the limitations of this pilot study, the more rigid tray/impression material combinations more accurately replicated stone dies.

Analysis of Variance↗