Abstract: Purpose This study compared weave patterns and glass compositions of five glass fiber materials found in commercial fiber-reinforced dental composites. Materials and Methods A scanning electron microscope (SEM) was used to investigate the woven structure of five glass fiber products, and an energy-dispersive x-ray spectrometer (SEM/EDS) was used to determine the elemental composition of these glass fibers in the bulk and at the surface of the fiber. Five fibers of each product were analyzed. Results The fiber products were either unidirectional rovings or bidirectional weaves. More precisely, the woven structures were linen weave, twill weave, or twill weave ribbon. SEM/EDS analysis revealed that the composition of the glass fibers was typical for E (electrical)-glass fibers with one exception. One product intended for use in fixed prosthodontics included unidirectional fibers with a composition consistent with a modified high-tensile-strength R-glass. Boron oxide found on the surface of glass fibers would likely contribute to an increased potential for corrosion of fiber-reinforced composite. Conclusions The predominant fiber composition in these products is E-glass. Because the degree of hydrolytic stability of polymer-fiber composites over time may lead to material failure in permanent restorations, this property should be investigated further.

Abstract: The restoration of patients with dental implants presents many challenges. Some of the common concerns and problems are difficulty in achieving a passive-fitting cast framework and loosening of prosthesis-retraining screws or abutment screws when using external hex prosthesis connection systems. The ITI system uses a unique connection of the abutment to the prosthesis-anchoring component. Because of this unique connection, many problems encountered with external hex designs have been greatly reduced or eliminated by the ability to more easily restore individual teeth with individual implants. This article will present the rationale for restoration of a patient with implants using individual implant-supported restorations.

Abstract: PURPOSE: Previous research has shown that dental gypsum casts may be effectively disinfected by the substitution of 10% of the gauging water with 5.25% solution of sodium hypochlorite. The purpose of this investigation was to determine the properties of gypsum produced from such a solution as opposed to tap water alone. MATERIALS AND METHODS: Tests included setting time, compressive strength, rigidity, diametral tensile strength, setting expansion, hardness, and detail reproduction. RESULTS: The addition of sodium hypochlorite to the gauging water resulted in a statistically significant increase in the compressive strength and rigidity, and a decrease in setting time (p < or = .5). All other properties remained unchanged. CONCLUSIONS: This substitution may be an effective and convenient method of disinfecting gypsum casts in the laboratory without adversely effecting physical and mechanical properties.

Abstract: Purpose Materials used to fabricate the most dimensionally accurate implant casts have not been identified experimentally. The purpose of this investigation was to examine the dimensional accuracy of implant casts fabricated with different materials. Measurements of linear horizontal dimensional change and strain produced on a master framework were evaluated and correlated. Materials and Methods A master framework was fabricated to fit an aluminum five-implant model. Forty polyether implant impressions of the aluminum model were randomly grouped and poured in either Vel-mix, Die Keen, Resin Rock, or Low Fusing Alloy. A digital veneer caliper was used to measure linear distance between the most distal abutments on each of the experimental implant casts and the master model. In addition, strain values were recorded from strain gauges bonded in the mesiodistal axis of the framework, which was secured by prosthetic retaining screws torqued to 10 Ncm. Results A one-way ANOVA showed a significant difference among the four die materials in dimensional change of the experimental casts (p= .0001). A post-hoc Duncan's multiple-range test (p < .05) showed that casts fabricated with Low Fusing Alloy had the least linear dimensional change from the master cast, but the material exhibited the greatest dimensional variability. A MANOVA (Wilks' Lambda) showed significant differences in strain on the framework based upon die material (p= .015). A post-hoc Duncan's multiple-range test (p < .05) showed that Resin Rock casts induced significantly less strain on the framework than the other materials. Negligible correlation was found between the linear horizontal dimensional change and the total absolute strain on the framework. Conclusion Experimental implant casts made of Resin Rock minimized strain on the master framework and decreased the amount of framework distortion on casts of this material. Low Fusing Alloy yielded accurate casts, but highly variable linear dimensional changes in the horizontal dimension may preclude its clinical benefit.

Abstract: Purpose To determine if using CIE L*a*b* color measurements of white facial skin could be correlated to those of silicone shade samples that visually matched the skin. Secondly, to see if a correlation in color measurements could be achieved between the silicone shade samples and duplicated silicone samples made using a shade-guide color formula. Materials and Methods A color booth was designed according to ASTM specifications, and painted using a Munsell Value 8 gray. A Minolta colorimeter was used to make facial skin measurements on 15 white adults. The skin color was duplicated using custom-shaded silicone samples. A 7-step wedge silicone shade guide was then fabricated, representing the commonly encountered thicknesses when fabricating facial prostheses. The silicone samples were then measured with the Minolta colorimeter. The readings were compared with the previous L*a*b* readings from the corresponding patient's skin measurements, and the relative color difference was then calculated. Silicone samples were fabricated and analyzed for three of the patients to determine if duplication of the visually matched silicone specimen was possible using the silicone color formula, and if the duplicates were visually and colorimetrically equivalent to each other. The color difference Delta E and chromaticity was calculated, and the data were analyzed using a coefficient-of-variation formula expressed by percent. A Pearson Product Moment Correlation Coefficient was performed to determine if a correlation existed between the skin and the silicone samples at the p .05 level. Results The highest correlation was found in the b* dimension for silicone thicknesses of 1 to 4 mm. For silicone thicknesses of 6 to 10 mm, the highest correlation was found in the L* dimension. All three dimensions had positive correlations (R2 > 0), but only the 1-mm and 4-mm b* readings were very strong. Patient and silicone L*a*b* measurement results showed very little change in the a* axis, while the L* and b* measurements showed more change in their numbers, with changes in depth for all patient silicone samples. Delta E numbers indicated the lowest Delta E at the 1-mm depth and the highest Delta E at the 10-mm depth. All duplicated samples matched their original silicone samples to a degree that visual evaluation could not distinguish any color differences. Using volumetric measurements, a shade guide was developed for all 15 patients. Conclusions There was good correlation between the patient's colorimeter measurements and the silicone samples, with the b* color dimension the most reproducible, followed by the L* and the a*. Silicone samples at 6, 8, and 10 mm matched the patient the best, and this study showed that silicone samples can be duplicated successfully if a good patient-silicone match is obtained. Rayon flocking fibers and liquid makeup are effective at matching facial prostheses and can be used to develop a simple shade guide for patient application.

Abstract: Purpose The purpose of this study was to examine the effect of resin adhesive/cement system primer and cement polymerization mode (auto- vs dual-polymerized) on the shear bond strength to dentin. Materials and Methods Dentin surfaces of 90 bovine teeth were polished to 600 grit. The dentin was etched for 15 seconds with phosphoric acid, rinsed, and blotted. Three adhesive systems, All-Bond 2, Prime & Bond 2.1 Dual-Cure, or Scotchbond Multi-Purpose Plus, were applied. Three primer polymerization methods were used with each system: dual-polymerized, autopolymerized, or strictly following manufacturers' recommendations. Resin cements, which were also either auto- or dual-polymerized, were applied to dentin using gelatin capsules. Shear bond strengths were determined using an Instron universal testing machine. Results The greatest bond strength, 15.4 MPa, was found with the Scotchbond system when the primer was dual-polymerized and the cement was autopolymerized. The lowest bond strength, 7.5 MPa, was found with All-Bond 2/Duo-Link, when the primer and cement were dual-polymerized. The autopolymerization mode produced the highest mean bond strength for All-Bond 2, while dual-polymerization of primer and cement resulted in the highest mean bond strength for Prime & Bond 2.1. Scotchbond Multi-Purpose Plus was least affected by the polymerization method. Two-way ANOVA showed that the interaction between the type of adhesive system and the method of polymerization significantly influenced bond strength (p= .0001). Conclusions The effect of the primer polymerization method on ultimate bond strength was different for each adhesive system evaluated. More research is needed to elucidate the interaction between adhesive system and method of polymerization on bonding of resin cements to dentin.

Abstract: Purpose This study was performed to investigate the effect of a carbonated beverage on the wear of human enamel and three dental ceramics: a conventional porcelain (Vitadur Alpha), a hydrothermal low-fusing ceramic (Duceram-LFC), and a machinable ceramic (Vita Mark II). Materials and Methods Tooth-against-ceramic specimens (10 per group) were tested in a wear machine under a load of 40N, at a rate of 80 cycles per minute, and for a total of 25,000 cycles. The test was performed in distilled water or with intermittent exposure to a carbonated beverage (Coca-Cola). Wear was determined by measuring the height reduction of the tooth specimens and the depth of wear track in the ceramic specimens. Results ANOVA revealed a significant difference among the groups for both enamel and ceramic wear (p < .001). When tested in water. Alpha porcelain caused significantly more enamel wear and also exhibited greater wear than Duceram-LFC and Vita Mark II. However, with exposure to the carbonated beverage, the enamel wear produced by Duceram-LFC did not differ significantly from that produced by Alpha porcelain, and Vita Mark II produced the least amount of enamel wear. Overall, exposure to the carbonated beverage significantly increased the enamel wear. The wear of Duceram-LFC and Vita Mark II increased with exposure to the carbonated beverage. Conclusions It was concluded that exposure to the carbonated beverage accelerated the enamel wear and decreased the wear resistance of Duceram-LFC and Vita Mark II ceramics. Overall, Vita Mark II was shown to be the most resistant to wear and also significantly less abrasive than conventional Alpha porcelain.

Abstract: Scleroderma is a multisystem connective tissue disease of unknown etiology, which is characterized by inflammation, vascular, and fibrotic changes of the skin as well as various internal organs. This article will review the systemic form of scleroderma known as CREST syndrome, its clinical manifestations including the dentofacial complications, as well as provide information to assist the prosthodontist in managing the dental treatment for patients with this disease.

Abstract: This article describes a technique for the easy fabrication of a template to facilitate surgical lengthening of the clinical crown to enhance esthetics and/or increase retention of a fixed prosthesis. The use of this surgical guide should result in more predictable clinical results.

Abstract: Osseointegration is defined as a direct interaction of bone to an implant surface. As a result, the implant fixture is immobilized in the bone and lends itself to function as an anchor for orthodontic tooth movements. When properly treatment-planned, these implants can also be used as prosthodontic abutments for single crowns, or removable or fixed partial dentures. This article describes how implant fixtures were surgically placed within the maxillary and mandibular arches of a partially edentulous patient, and used for orthodontic anchorage to reposition the remaining teeth into a more favorable arch position, creating increased posterior interocclusal space. The fixtures were then restored with fixed partial dentures to rehabilitate the patient into a mutually protected occlusion.

Abstract: Purpose In vitro bond strengths of traditional denture base acrylic resin (Lucitone 199) to a cobalt-chromium partial denture alloy (J.D. Partial Denture Alloy) were tested using two surface pretreatments (sandblast, sandblast and electrochemical etch) with three adhesive primers: Lee Metal Primer, Acrylic Solder, and CR Inlay cement. A sandblasted group with no primer served as the control. Materials and Methods The alloy specimens (8.0-mm bonding diameter) were cast and invested to receive a traditional denture base resin after surface treatments (sandblasted, and sandblasted-electrochemically etched) and application of adhesive primers. The bonded specimens were stored in distilled water at 37°C for 24 hours and divided into two groups. The first group was debonded in tension on a testing machine at a cross-head speed of 0.05 cm/min. The second group was subjected to thermocycling of 1,000 cycles and then tested for tensile bond strength. The force at which the bond failed was recorded, and the bond strength was calculated in megapascals (MPa). The sites of bond failure were examined, quantified under (20x) magnification, and recorded. Ten specimens were evaluated for each experimental condition for a total of 160 specimens. Data were analyzed by ANOVA with a factorial design. Means were compared by Tukey intervals at the 0.05 significance level. Results Significant differences in bond strength were observed, with primers being the most important factor, followed by pretreatment and storage and thermocycling with significant interactions. Sandblasted-electrochemically etched alloy with primers more effectively enhanced bond strength of the denture base resin to the treated alloy than sandblasted alloy with primers. Thermocycling had a greater effect on bond strength of the specimens with Acrylic Solder when compared with Lee and CR Inlay primers. The highest bond strengths (>18.0 MPa) were observed for the conditions involving electrochemical etching and the priming with CR Inlay cement (both after 24 hours and thermocycling of 1,000 cycles). For primed specimens, the bond failures occurred cohesively within the primers or the denture resin and adhesively between the primers and the denture base resin, or between primers and alloy. For nonprimed, the bond failures occurred adhesively at the denture base resin-metal interface. Conclusions Nonprimed specimens (both sandblasted and electrochemically etched) had lowest bond strength (0.4 ± 0.1 MPa; 0.3 ± 0.4 MPa). The bond strengths of the primed treated specimens were improved significantly. The CR Inlay-treated specimens exhibited the highest bond strength (20.6 ± 6.3 MPa). After thermocycling for 1,000 cycles, the bond strengths of the specimens were significantly lower than the bond strengths of the specimens after 24 hours.

Abstract: Purpose In 1996, a survey of American dental schools was conducted. The purpose of the survey was to determine the curricular structure, techniques taught, and materials used in predoctoral fixed prosthodontics courses. Materials and Methods The survey was mailed to the course directors of predoctoral fixed prosthodontic programs at 53 American dental schools. Of these, 42 schools returned the completed survey, resulting in a response rate of 79%. The mean, median, and the range of responses were computed where applicable. Results The results from this survey show that the mean student-to-faculty ratio in the preclinical course was 11:1, with a median of 10:1 and a range of 5:1 to 25:1. The mean number of laboratory clock hours was 164, with a median of 148 and a range of 81 to 288. The mean number of lecture hours reported was 42, with a median of 35 and a range of 20 to 80. Fifty-five percent of the schools used the Hanau semiadjustable articulator. The most commonly used provisional technique was the thermoplastic custom external surface form (44%). The finish line of choice for the full metal restoration was the chamfer placed circumferentially (74%). The finish line of choice for the porcelain-fused-to-metal restoration was the shoulder placed facially and the chamfer placed lingually (38%). Conclusions Predoctoral fixed prosthodontics education and technical experience varies from school to school, yet a large percentage of schools agree on certain topics.

Abstract: Prosthodontic educators participated in a workshop held at The American College of Prosthodontists annual session in Kansas City, MO, in October 1996. Their goal was to review elements of the predoctoral prosthodontic curriculum to establish a consensus on the levels of expected skill and knowledge. Skill components were designated at the competency and exposure levels, while knowledge components were designated at the understanding and familiarity levels. The workshop recommendations were distributed to American and Canadian dental schools and the communities of interest for comments in January 1997. The workshop recommendations were reviewed and finalized at the American Association of Dental Schools annual meeting in Orlando, FL, in March 1997. The recommendations may be used by dental educators to prioritize curricular elements in relation to limited time dedicated to the prosthodontic curriculum. Outcomes assessment methods will be needed to ensure competency in the new dentist.

Abstract: Purpose Using the one-step polyvinyl siloxane impression technique, this study compared the effect of putty material working time on the dimensional accuracy of recovered improved stone casts. Materials and Methods An acrylic resin master cast was fabricated with embedded reference points to enable both horizontal and vertical measurements. Four commercially available polyvinyl siloxane impression putties with light body washes were evaluated: 1) Extrude (Kerr), 2) Cutter (Coltere), 3) Express (3M), and 4) Reprosil (Caulk). Each putty was mixed by hand for 30 seconds, placed in a plastic stock tray, and seated on the master cast at 0, 30, 60, 90, and 120 seconds after mixing (N = 100, n = 5). The impressions were poured in improved stone, and vertical and horizontal measurements were made to 0.001 mm between reference points on recovered casts using an optical traveling microscope. ANOVA (p .05) was used to compare vertical and horizontal measurements to master cast dimensions. Results No statistically significant difference was found among casts for all materials and time periods tested. When horizontal measurement ranges were evaluated, Extrude casts exhibited the widest range of measurement, especially when the trays were seated at 90 and 120 seconds. When vertical measurement ranges were evaluated, Express casts at 120 seconds exhibited the widest range. Conclusions A high range of variability in vertical and horizontal dimensions occurred at the later time periods, especially for Extrude and Express casts. As a result of rapid polymerization and poor flow properties of putty materials, the impression tray should be seated within 60 seconds after putty mixing to reduce dimensional variability of recovered casts.

Abstract: Purpose The accuracy of master cast reproduction by a polyvinylsiloxane impression material using two visible-light-curing resin and an autopolymerizing polymethyl methacrylate resin custom tray materials was investigated. Materials and Methods Custom trays were fabricated from a master cast that had three index points marked on both the inner and outer vestibules. Impressions were made of the master cast using Extrude and then poured in Die Keen Green stone. The distances between the reproduced index points were measured to ±0.01 mm with a traveling microscope and the algebraic norms calculated for each tray material. Results No differences (p > .05) were found in the dimensions of the inner index points, while the separations of the outer index points indicated that there were differences in the accuracy of reproduction (p > .01) by the three tray materials. The index points reproduced on the casts, compared with the master cast, were closer together for the Triad Blue trays than for the TruTray and Ontray impression trays. Conclusions All three tray materials produced acceptable casts, but the greatest accuracy was achieved with TruTray, followed by Ontray. Triad Blue produced casts that were slightly smaller than the master. In practice, the small measured differences in cast dimensions may not have clinical significance.

Abstract: Purpose The purpose of this investigation was to examine the tear strength of four irreversible hydrocolloid (alginate) impression materials (Tare-Free Alg, Jeltrate, Identic, and Kromopan). Materials and Methods Eighty specimens, 20 for each alginate tested, were according to the manufacturers' instructions. A cutting die described in American Standard Test and Material document D-1004-94a was used to prepare test specimens. Immediately after removal from the cutting die, test specimens were measured at five points with an electronic caliper. Test specimens were placed into a specialized jig, and a Shimpo force gauge was used to measure tear strength. The tear test was performed no more than 10 minutes after mixing the alginate material with water. The tear strength was then calculated. One-way ANOVA was used to compare the mean force required to induce tearing for each of the four groups, followed by the Newman-Keuls pairwise multiple comparisons test. Results Results were considered statistically significant at p < .05. There was a statistically significant difference between alginate materials (p < .0001). The Newman-Keuls multiple comparisons procedure showed that Tare-Free Alg (514.5 g/cm) had a significantly higher tear strength value (p < .0001) than Jeltrate (259.0 g/cm), Identic (289.9 g/cm), and Kromopan (323.9 g/cm). Conclusions Tara-Free Alg had the highest tear strength value, followed by Jeltrate, Identic, and Kromopan.

Abstract: One of the conservative and successful modalities of treatment for obstructive sleep apnea is the mandibular advancement prosthesis. This prosthesis engages teeth on both dental arches for retention and stability. This article describes a technique that allows that fabrication of such a prosthesis in one piece and in a single laboratory step. This may be beneficial in reducing the laboratory time required for fabrication of such a prosthesis.

Abstract: The selection of appropriate implant treatment modalities for the edentulous maxillary arch is complex. Although many patients are candidates for an implant-supported removable prosthesis, two major considerations affecting choice of treatment type are the amount of residual alveolar bone and soft tissue, and cost. A technique is described that employs a cast milled primary bar and a secondary casting constructed using a vacuum-formed 0.040-in plastic matrix. The secondary casting is intimately adapted to the primary bar and incorporates the retentive elements within it. The resulting prosthesis is less expensive than comparable designs, and retentive elements are easily replaceable. The technique is adaptable to most implant systems. The matrix-assisted secondary casting technique provides a design that is esthetic and hygienic. The prosthesis may also be easier to insert and remove than implant-supported removable prostheses that use plunger- or latch-type retention.

Abstract: Implant impression copings reduce access to prepared teeth during the impression-making process. If the impression copings and teeth are in close proximity, it may be difficult to extrude impression material circumferentially around the margins of the tooth preparations. A technique is described that allows the impressions of the prepared teeth to be made without the implant impression copings interfering. The advantages and disadvantages of the technique are discussed.

Abstract: A rationale for the use of Twin-Flex clasps is presented. Twin-Flex clasps may provide improved esthetics, an increased number of clasping sites, and enhanced patient comfort when compared with conventional clasping systems. Two fabrication methods are described, and departures from conventional clasping techniques are explained.

Abstract: PURPOSE The purpose of this investigation was to determine the mean marginal discrepancy of metal-ceramic crowns fabricated with gold cylinders and cemented on implant abutments. These discrepancies were then compared with those measured previously for implant-supported ceramic crowns. MATERIALS AND METHODS Fifteen Nobel BioCare CeraOne abutments were connected to implant fixtures embedded in acrylic resin blocks. Marginal discrepancies were determined for gold cylinders, gold cylinders plus ceramic alloy (metal frameworks), completed metal-ceramic crowns, and cemented metal-ceramic crowns using a stereomicroscope equipped with a video camera linked to a computer. A Hotelling's T2 test (p < or = .05) was used to evaluate potential differences in mean marginal discrepancies among groups. RESULTS The mean marginal discrepancies were: 1) gold cylinders, 7.56 +/- 2.73 microns; 2) metal frameworks, 6.21 +/- 1.34 microns; 3) metal-ceramic crowns, 11.06 +/- 3.21 microns; and 4) zinc-phosphate cemented crowns, 31.47 +/- 6.65 microns. No significant difference between gold cylinders and metal frameworks was found. Mean marginal discrepancies for metal-ceramic crowns were significantly greater than discrepancies for cast gold cylinders. Cemented-crown mean marginal discrepancy was significantly greater than all other means. CONCLUSIONS Cemented metal-ceramic crowns fabricated using proprietary gold cylinders exhibited well-fitting margins (31.47 microns).

Abstract: Clinicians have long expressed concern about the accuracy of the Gothic arch tracing for recording centric relation in edentulous patients. With the use of dental implants to assist in retaining complete dentures, the problem of inaccurate recordings, made for patients without natural teeth, can be significantly reduced. This article presents a technique that uses healing abutments to stabilize the record bases so that an accurate Gothic arch tracing can be made.

Abstract: The dental computed tomographic (CT) scan is useful in presurgical planning for implant prosthodontics. To provide accurate information, the patient must be positioned properly during the scan procedure. This article describes a method for fabricating a template that provides guidance to the CT technologist for desired head orientation of the patient.

Abstract: Purpose A survey of prosthodontists who have not achieved diplomate status from the American Board of Prosthodontics was conducted to identify the reasons why they have or have not pursued and/or achieved board certification in prosthodontics. Materials and Methods A survey was sent to 500 educationally qualified or board-eligible prosthodontists in the summer of 1997. A total of 364 responses were received, for a response rate of 73%. The responses and comments were analyzed. Results The majority of respondents listed private practice as their primary area of professional activity. Personal accomplishment was cited by 80% of the respondents as a major motivational factor. Three major impediments to taking the examination included: time away from practice (65%), time away from family (59%), and financial sacrifice (57%). More than one third of the respondents believed there was no advantage to attempting the board examination. Less than half of the respondents have attended The American College of Prosthodontists (ACP)-sponsored Board Preparation Course, and half have used the ACP Study Guide. The respondents have perceived these to be useful in their preparation efforts. The survey presented four potential changes in the exam format that might encourage greater participation in the board-certification process. Respondents showed the greatest support (64%) for the concept of a written examination only (ie, elimination of Parts 2, 3, and 4). Conclusions Personal accomplishment was the most important motivational factor in starting the examination process. The greatest impediments to pursuing board certification were the time involved and financial resources expended. The greatest interest in a potential change in the examination format was the use of a written examination only.

Abstract: Purpose This study compared the quantity of preweighed, packaged die stone use to bulk die stone use by dental students. Materials and Methods Starting in September 1994, all the bulk die stone was removed from the dental clinic, and only preweighed packages of die stone (Silky-Rock, Whip Mix) were available to students. At the end of August 1995 and August 1997, the amount of preweighed die stone used by the students was determined and compared with the amount of bulk die stone (DieKeen, Modern Materials) used during the period of September 1993 to August 1994. Results Between September 1994 and August 1997, the students used 42% less per annum of the preweighed, packaged die stone than the previous annual use of bulk die stone. The laboratories were much cleaner when the preweighed packages were used, and fewer cleaning staff were required. The environment was also cleaner for the laboratory staff, who used to fill the bulk containers with gypsum products. Conclusions Students used 42% less die stone per annum when using the preweighed packages.

Abstract: Pneumatic vessels used in dentistry provide a pressurized environment to enhance the outcome of many laboratory procedures. A pressurized environment directs volume loss associated with polymerization shrinkage, minimizes air inclusions in powder/liquid mixtures, raises the boiling point of liquids, and facilitates flow of impression and replication materials, improving surface detail. The following report illustrates the usefulness of a reliable pneumatic vessel during denture base repair resin processing and replication of pattern details.

Abstract: The record base for a multiple, implant-supported, fixed prosthesis may be attached to the implants by screws. The screw attachment provides a stable record base for recording maxillo-mandibular relationships. Extraoral adjustment of the occlusion rim requires that it be unscrewed to allow removal from the mouth. The rim must be reattached with screws for the next intraoral evaluation. Although this cycle of removal and replacement provides stability, retention, and accuracy, it is time-consuming and inefficient. To resolve this problem, a two-piece record base/occlusion rim can be used. The screw-retained record base remains intraoral for the duration of the clinical appointment. The occlusion rim is designed to fit over the record base, with retention and stability, without screw retention. Use of the two-piece record base/occlusion rim facilitates convenient removal, adjustment, and replacement of the occlusion rim.

Abstract: A technique using a custom-made cast alloy attachment housing for an implant-retained overdenture prosthesis is presented. Common problems encountered in implant-tissue bar-retained overdentures are discussed. Details of the modified laboratory procedure are described. This technique provides the clinician with an alternative for predictably treating patients with implant-retained overdentures.