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Converting the patient's clinical information into the virtual world is a prerequisite for the computer-aided design and computer-aided manufacturing (CAD-CAM) of dental restorations. This article describes a modified facebow which facilitates the radiation-free registration of the maxillary teeth to a 3-dimensional face image for transfer to a virtual articulator. This facebow can be easily fabricated with minimal materials and adjusted to fit different patients; its error in tooth registration was demonstrated to be less than 1 mm., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Fluorophlogopite glass ceramic (FGC) is a biocompatible, etchable, and millable ceramic with fluoride releasing property. However, its mechanical properties and reliability compared with other machinable ceramics remain undetermined., Purpose: The purpose of this in vitro study was to compare the mechanical properties of 3 commercially available millable ceramic materials, IPS e.max CAD, Vitablocs Mark II, and Vita Enamic, with an experimental FGC., Material and Methods: Each type of ceramic block was sectioned into beams (n=15) of standard dimensions of 2×2×15 mm. Before mechanical testing, specimens of the IPS e.max CAD group were further fired for final crystallization. Flexural strength was determined by the 3-point bend test with a universal loading machine at a cross head speed of 1 mm/min. Hardness was determined with a hardness tester with 5 Vickers hardness indentations (n=5) using a 1.96 N load and a dwell time of 15 seconds. Selected surfaces were examined by scanning electron microscopy and energy-dispersive x-ray spectroscopy. Data were analyzed by the 1-way ANOVA test and Weibull analysis (α=.05). Weibull parameters, including the Weibull modulus (m) as well as the characteristic strength at 63.2% (η) and 10.0% (B10), were obtained., Results: A significant difference in flexural strength (P<.001) was found among groups, with IPS e.max CAD (341.88 ±40.25 MPa)>Vita Enamic (145.95 ±12.65 MPa)>Vitablocs Mark II (106.67 ±18.50 MPa), and FGC (117.61 ±7.62 MPa). The Weibull modulus ranged from 6.93 to 18.34, with FGC showing the highest Weibull modulus among the 4 materials. The Weibull plot revealed that IPS e.max CAD>Vita Enamic>FGC>Vitablocs Mark II for the characteristic strength at both 63.2% (η) and 10.0% (B10). Significant difference in Vickers hardness among groups (P<.001) was found with IPS e.max CAD (731.63 ±30.64 H(V))>Vitablocs Mark II (594.74 ±25.22 H(V))>Vita Enamic (372.29 ±51.23 H(V))>FGC (153.74 ±23.62 H(V))., Conclusions: The flexural strength and Vickers hardness of IPS e.max CAD were significantly higher than those of the 3 materials tested. The FGC's flexural strength was comparable with Vitablocs Mark II. The FGC's Weibull modulus was the highest, while its Vickers hardness was the lowest among the materials tested., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Excessive movable tissue is a challenge in complete denture prosthetics. A modified impression technique is presented with polyvinyl siloxane impression material and a custom tray with relief areas and perforations in the area of the excessive movable tissue., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Oral rehabilitation after a mandibulectomy is a challenge for prosthodontists. This clinical report describes the management of a 54-year-old man, who, after a mandibulectomy, had rotation of the mandible, with a revascularized flap, followed by an implant-supported prosthesis and ceramic restorations., (Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

There is limited knowledge about the changes that proximal contacts between implant-supported prostheses and adjacent teeth undergo over time. This report describes the management of a clinical situation with the loss of proximal contact between implant-supported prostheses and adjacent natural teeth in a partially edentulous patient., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Prosthodontic rehabilitation of a surgically resected/reconstructed jaw with a conventional tissue-borne dental prosthesis is often challenging, if not impossible, because of the suboptimal conditions of the soft and hard tissue topography/architecture of the reconstructed site. Placing dental implants in grafted bone to provide appropriate support, stability, and retention for prosthodontic rehabilitation offers the potential for improved oral function. There are, however, some clinical conditions for which an implant-supported removable prosthesis may be preferred to a fixed implant prosthesis. This clinical report describes the design and fabrication of a milled bar and a tooth- and implant-supported removable dental prosthesis for oral rehabilitation of a reconstructed mandible, which considers patient factors associated with oral and financial conditions, ease of oral hygiene procedures, and long-term maintenance., (Copyright 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Early loss of magnetic keepers in cast gold posts is seen in clinical practice., Purpose: The purpose of this vitro study was to investigate the effect of burn-out temperature on the retention of magnetic keepers in cast gold alloy and on the thickness of the oxide layer at the keeper-alloy interface., Material and Methods: One hundred and five keepers (Magfit EX) were cast with gold alloy (Protor 3) at 3 different burn-out temperatures: 500 degrees C, 600 degrees C, or 700 degrees C (n=35). To test for retention of keepers, 60 specimens (n=20) were tested to failure in tension mode in a universal testing machine (UTM); 45 specimens (n=15) were sectioned, and the interface was evaluated under a scanning electron microscope (SEM). Tensile force data were analyzed with 1-way ANOVA, and SEM data were analyzed with 1-way repeated measures ANOVA. Bonferroni multiple comparisons were performed for post hoc analysis (alpha=.05)., Results: Retention of the keepers was significantly higher at lower burn-out temperatures (P<.001). The retention of the keepers became unpredictable and immediate failures were observed at a burn-out temperature of 700 degrees C. Oxide formation at the keeper-alloy interface was significantly less at lower burn-out temperatures (P<.001)., Conclusions: A burn-out temperature of 500 degrees C for casting the Magfit EX keeper with type IV high-strength gold alloy is recommended.

The casting of extensive implant superstructures that have a good passive fit may be technically demanding. A simple, 2-stage casting technique is presented that avoids common problems associated with the casting of large superstructures. The fabrication of a 7-unit metal-ceramic screw-retained fixed partial denture supported by 5 implants is used to illustrate this technique.

Statement of Problem: Relining and rebasing of complete dentures are common procedures to improve the fit of the prostheses. After relining or rebasing, adjustments may be required because of dimensional change that occurs during reprocessing of the denture when new denture base material is polymerized., Purpose: This study analyzed the linear dimensional change of heat cured acrylic resin that occurs during reline and rebase procedures for complete dentures., Material and Methods: Twenty-two maxillary and mandibular complete denture bases with artificial teeth were saturated by immersion in distilled water at 37 degrees C +/- 1 degree C. Fine crosses were marked on the incisal edges of the central incisors and the supporting cusps of the second molar teeth. Distances between the marks were measured with a high resolution traveling microscope. Heat-cured acrylic resin was processed by a long curing cycle of 72 degrees C for 6.5 hours, then heated to 100 degrees C for over 30 minutes and kept at 100 degrees C for 1 hour. The relined or rebased denture was allowed to cool slowly in the water bath for 48 hours to reach ambient temperature. The reference-crosses were measured immediately after careful deflasking., Results: In the relining procedure, all incisor-molar and intermolar distances exhibited shrinkage of 0.3%, despite different shapes of maxillary and mandibular dentures. Results of the rebasing procedure were similar to that of the reline expect that only 0.1% intermolar shrinkage was found on the maxillary denture., Conclusion: Shrinkage was approximately 0.15 mm for an interarch distance of 50 mm. This degree of change is both clinically undetectable and insignificant. Using this processing cycle for acrylic resin in reline or rebase procedures did not cause clinically significant dimensional changes to complete dentures.