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Biomedical subjects

Ariel J Raigrodski

Publications and source records attributed to Ariel J Raigrodski.

17 recordsLinked to original sources
PubMed2006

A technique for locating implant abutment screws of posterior cement-retained metal-ceramic restorations with ceramic occlusal surfaces.

With the increased use of cement-retained implant-supported restorations for the replacement of missing teeth, clinicians may choose to use a definitive cement to lute the definitive restoration. A complication that may occur, especially for a single-tooth replacement, is loosening of the abutment screw. In those situations, it may be difficult to locate the abutment-screw access to remove the restoration. The purpose of this article is to describe a technique that may facilitate the clinician's ability to locate the abutment-screw access in the event of abutment-screw loosening, thus reducing the need for refabricating the restoration.

Cementation↗
PubMed2006

Retention of zirconium oxide ceramic crowns with three types of cement.

STATEMENT OF PROBLEM: Information about the retentive strength of luting agents for zirconium oxide-based crowns is limited. It is unknown if this type of high-strength ceramic restoration requires adhesive cementation to enhance retention. PURPOSE: The purpose of this in vitro study was to determine the ability of selected luting agents to retain a representative zirconium oxide ceramic crown under clinically simulated conditions. MATERIAL AND METHODS: Recently extracted human molars were prepared with a flat occlusal surface, 20-degree taper, and approximately 4-mm axial length. The axial and occlusal surface areas were determined, and specimens were distributed equally by total surface area into 3 cementation groups (n=12). Zirconium oxide ceramic copings (Procera AllZirkon) with an occlusal bar to facilitate removal were fabricated using computer-aided design/computer-assisted manufacturing (CAD/CAM) technology. All copings were airborne-particle abraded with 50-mum Al(2)O(3) and then cleaned in an ultrasonic bath with isopropyl alcohol. Provisional cement was removed from the prepared teeth, followed by a pumice prophy. After trial insertion, the copings were cleaned with phosphoric acid, rinsed, dried, and dehydrated with isopropyl alcohol. They were then cemented with a seating force of 10 kg per tooth, using either a composite resin cement with adhesive agent (Panavia F 2.0 and ED Primer A & B [PAN]), a resin-modified glass ionomer cement (Rely X Luting [RXL]), or a self-adhesive modified composite resin (Rely X Unicem [RXU]). The cemented copings were thermal cycled at 5 degrees C and 55 degrees C for 5000 cycles with a 15 second dwell time, and then removed along the path of insertion using a universal testing machine at 0.5 mm/min. The removal force was recorded, and the stress of dislodgement was calculated using the surface area of each preparation. A 1-way analysis of variance was used to analyze the data (alpha=.05). The nature of failure was also recorded. RESULTS: Mean dislodgement stresses were 5.1, 6.1, and 5.0 MPa for PAN, RXL, and RXU, respectively. The 1-way analysis of variance revealed no differences in mean crown removal stress among the 3 cementation groups. The predominant mode of failure was cement remaining principally on the zirconium oxide copings in 46% of the specimens, followed by cement found on the tooth in 25.7% of the specimens. CONCLUSIONS: Within the limitations of this study, the 3 luting agents, with mean removal stresses ranging from 5.0 to 6.1 MPa were not significantly different. The use of a composite resin cement with a bonding agent did not yield higher coping retention compared to the other 2 cements tested.

Adhesiveness↗
PubMed2006

The efficacy of posterior three-unit zirconium-oxide-based ceramic fixed partial dental prostheses: a prospective clinical pilot study.

STATEMENT OF PROBLEM: Although zirconium-oxide-based restorations for fixed partial denture prostheses (FPDPs) are available for use, clinical studies evaluating their longevity and related complications have not been published. PURPOSE: The aim of this pilot clinical study was to assess the efficacy of zirconia-based posterior 3-unit FPDPs. MATERIAL AND METHODS: Twenty 3-unit posterior FPDPs (Lava) were placed in 16 subjects who were missing a second premolar or a first molar, met specific inclusion and exclusion criteria, and provided informed consent. All teeth were prepared in a standardized manner: occlusal reduction of 1.5 to 2 mm; axial reduction of 1 to 1.5 mm; a 1.0-mm, 360-degree rounded shoulder placed 0.5 mm subgingivally on the facial aspect and supragingivally on the lingual aspect on sound tooth structure; and rounded internal line angles. Impressions were made with vinyl polysiloxane (Express) impression material. Frameworks were fabricated using a computer-aided design/computer-assisted manufacturing technique with a retainer thickness of 0.6 mm, and a minimal connector surface area of 9 mm(2). Restorations were luted with resin-modified glass-ionomer cement (Rely X luting). Recall appointments were made after 2 weeks and 6, 12, 18, 24, and 36 months. Clinical fracture resistance, marginal discoloration, marginal adaptation, radiographic proximal recurrent decay, and periapical pathoses were assessed over time using modified Ryge criteria. The probability distributions of these variables were calculated for the baseline data as well as for recall data. RESULTS: Mean follow-up was 31.2 months. Fifteen restorations were rated Alpha in all measured parameters. Minor chipping of veneering porcelain was detected in 5 restorations rated Bravo for clinical fracture resistance and Alpha for all other assessed parameters. One restoration was rated Bravo in terms of marginal integrity at 36 months. CONCLUSIONS: Zirconia-based posterior 3-unit FPDPs performed well after short-term service.

Adult↗
PubMed2006

A survey of edentulous patient preference among different denture esthetic concepts.

STATEMENT OF PROBLEM: Despite the fact that solutions to functional problems are available, successfully restoring the appearance of an edentulous patient remains a challenge. PURPOSE: The aim of this survey was to determine if edentulous respondents could differentiate among three denture esthetic concepts and if there was an overall preference among the three. MATERIALS AND METHODS: Six edentulous test subjects were selected based on age and smile criteria. One wax tooth arrangement was completed according to each of the three esthetic concepts for a total of three wax tooth arrangements per test subject. The three esthetic concepts followed were natural, supernormal, and denture look. Standardized full-face digital photographs were made of each arrangement (three) during maximum smile for each subject (six). These 18 photographs were included in a questionnaire. Respondents were asked questions about their preference among the three randomly ordered concept photographs for each of the six subjects. A total of 147 completed questionnaires were analyzed. RESULTS: Ninety-six percent of respondents were able to differentiate among the three esthetic denture concepts. Natural tooth arrangements were preferred by 55% of the respondents, supernormal tooth arrangements were preferred by 19%, and the denture look arrangements were preferred by 26%. CONCLUSION: Within the limitations of this survey, the questionnaire respondents differentiated between the three esthetic denture concepts. The tooth arrangement most closely resembling the anatomical average was selected by 55% of the respondents. Preference for a particular concept changed when responses to each test subject set were considered individually. Demographic factors do not significantly affect patient preference. CLINICAL SIGNIFICANCE: Three esthetic concepts for complete denture construction have been differentiated. Questionnaire respondents preferred appearances that are far from the anatomical average 45% of the time.

Adult↗
PubMed2005

Accuracy of newly formulated fast-setting elastomeric impression materials.

STATEMENT OF PROBLEM: Elastomeric impression materials have been reformulated to achieve a faster set. The accuracy of fast-setting elastomeric impression materials should be confirmed, particularly with respect to disinfection. PURPOSE: The purpose of this study was to assess the accuracy of 2 types of fast-setting impression materials when disinfected with acid glutaraldehyde. MATERIAL AND METHODS: Impressions of the mandibular arch of a modified dentoform master model were made, from which gypsum working casts and dies were formed. Measurements of the master model and working casts included anteroposterior (AP) and cross-arch (CA) dimensions. A stainless steel circular crown preparation incorporated within the master model was measured in buccolingual (BL), mesiodistal (MD), and occlusogingival (OG) dimensions and compared to measurements from recovered gypsum dies. The impression materials examined were a fast-set vinyl polysiloxane (VPS-FS, Aquasil Ultra Fast Set), a fast-set polyether (PE-FS, Impregum Penta Soft Quick Step), and a regular-setting polyether as a control (PE, Impregum Penta). Disinfection involved immersion in 3.5% acid glutaraldehyde (Banicide Advanced) for 20 minutes, and nondisinfected impressions served as a control. Linear measurements were made with a measuring microscope. Statistical analysis utilized a 2-way and single-factor analysis of variance with pair-wise comparison of mean values when appropriate. Hypothesis testing was conducted at alpha = .05 RESULTS: No differences were shown between the disinfected and nondisinfected conditions for all locations. However, there were statistical differences among the 3 materials for AP, CA, MD, and OG dimensions. AP and CA dimensions of all working casts were larger than the master model. Impressions produced oval-shaped working dies for all impression materials. PE and PE-FS working dies were larger in all dimensions compared to the stainless steel preparation, whereas VPS-FS-generated working dies were reduced in OG and MD dimensions. Differences detected were small and may not be of clinical significance. CONCLUSIONS: Impression material accuracy was unaffected by immersion disinfection. The working casts and dies were similar for PE and PE-FS. VPS-FS generated gypsum dies that were smaller in 2 of the 3 dimensions measured and may require additional die relief. Overall accuracy was acceptable for all 3 impression materials.

Analysis of Variance↗
PubMed2005

All-ceramic full-coverage restorations: concepts and guidelines for material selection.

UNLABELLED: High-strength, all-ceramic systems for full-coverage restorations use all-ceramic core materials for the fabrication and processing of infrastructures (eg, crown copings, fixed partial denture frameworks) that are then veneered with porcelain. Not all of these all-ceramic core materials are alike, and as such, they present with different properties that may affect their indications and limitations, the laboratory procedures used for their processing, and their clinical handling. This article reviews their clinically relevant properties and discusses the effect of these characteristics on their indications and recommended clinical procedures. LEARNING OBJECTIVES: This article provides an overview of the clinically relevant properties of high-strength, all-ceramic systems used for aesthetic restorative dentistry. Upon reading this article, the reader should: Be able to differentiate among the principal all-ceramic material systems. Understand the clinical indications for contemporary, high-strength ceramics.

Aluminum Oxide↗
PubMed2004

Contemporary all-ceramic fixed partial dentures: a review.

High-strength all-ceramic systems for fixed partial dentures (FPDs)have become available for replacing missing teeth. New core materials have been developed and have evolved in the last decade,with yttrium tetragonal zirconia polycrystals (Y-TZP)-based materials being the most contemporary. With the emphasis on the use of computer-assisted design/computer assisted-manufacturing technology, various production techniques have been developed for enhancing the fabrication of consistent and predictable restorations in terms of strength, marginal fit, and esthetics. Although initial results are limited, results reported in scientific abstracts of ongoing clinical studies assessing the long-term success of three unit all-ceramic FPDs and anecdotal evidence published in peer reviewed articles on the use of Y-TZP-based restorative systems are encouraging. This article reviews the evolution and development of materials and technologies for all-ceramic FPDs.

Ceramics↗
PubMed2004

Contemporary materials and technologies for all-ceramic fixed partial dentures: a review of the literature.

High-strength all-ceramic systems for fixed partial dentures (FPDs) are available for replacing a missing tooth. New core/framework materials have been developed and have evolved in the last decade. With the advancement of CAD/CAM technology, various fabrication techniques have been developed for fabricating improved, consistent, and predictable restorations in terms of strength, marginal fit, and esthetics and for managing core/framework materials that could not otherwise be managed. This article reviews the evolution and development of materials and technologies for all-ceramic FPDs through data published between 1966 and 2004 in the English language. Peer-reviewed articles were identified through a MEDLINE search and a hand search of relevant textbooks and annual publications. The available information suggests that clinical data on the success of these restorations are limited, and that the results of long-term clinical studies are critical to the assessment of these restorations to provide more specific guidelines for usage.

Aluminum Oxide↗
PubMed2003

Esthetic techniques and restorative systems used in the second-year undergraduate dental curriculum.

Metal-free tooth-colored restorative systems for fabricating indirect intracoronal and extracoronal restorations have been developed because of patients' demand for superior esthetics. During the past decade, long-term clinical studies have demonstrated the success of many of these types of restorations in terms of function and esthetics. Ceramic veneers, all-ceramic crowns, ceramic onlays, and composite-resin inlays are becoming an integral part of contemporary clinical practice. The constant evolution in bonding techniques, adhesive systems, and cements plays a major role in the success of these metal-free restorations. In addition, home-bleaching procedures have become an integral part of the esthetically oriented dental practice. This article discusses the rationale, scientific basis, and implementation of a new undergraduate preclinical esthetics course for second-year dental students at the Louisiana State University Health Sciences Center School of Dentistry.

Crowns↗
PubMed2003

Clinical and laboratory considerations for the use of CAD/CAM Y-TZP-based restorations.

Prospective clinical studies are evaluating the long-term success of Y-TZP-based all-ceramic FPDs. Y-TZP-based infrastructures for crowns and FPDs present favorable physical, mechanical, and optical properties. Some Y-TZP-based restorative systems use CAD/CAM technology. Nevertheless, technicians should be able to employ traditional concepts of infrastructure design for both crowns and FPDs when using such materials. The purpose of this article is to review the properties of Y-TZP-based materials as a restorative infrastructure and to review the application of traditional concepts of framework design with CAD/CAM technology.

Computer-Aided Design↗
PubMedDate not supplied

Clinical considerations for enhancing the success of implant-supported restorations in the aesthetic zone with delayed implant placement.

Several factors (e.g., root configuration, periapical pathoses, periodontal disease, severe bone loss, patient accessibility) determine the timing of the implant placement. When delayed implant placement is the only feasible option for implant restoration, achieving a functional and aesthetic restoration is more complex and challenging. This article will discuss the surgical and prosthetic methods for enhancing the success of an implant-supported crown in the aesthetic zone in cases where delayed implant placement is the only available treatment option for patients missing single teeth.

Adult↗
PubMedDate not supplied

Clinical considerations in case selection for all-ceramic fixed partial dentures.

All-ceramic systems have been utilized for fixed partial dentures (FPDs) to replace a missing tooth since the early 1990s. Clinical studies that assess the long-term outcome of both anterior and posterior three-unit all-ceramic FPDs are required to determine whether they can serve as a viable treatment option for functional and aesthetic tooth replacement. This article discusses the evolution and development of all-ceramic systems for FPDs as well as the clinical and laboratory considerations for treating patients using these restorations.

Adult↗
PubMedDate not supplied

Efficacy of a computerized shade selection system in matching the shade of anterior metal-ceramic crowns--a pilot study.

OBJECTIVE: The purpose of this study was to determine whether anterior crowns fabricated using a computerized shade selection system (ShadeScan, Cynovad) (experimental procedure) match adjacent teeth better than anterior crowns fabricated using conventional shade prescription and clinical slides (control). METHOD AND MATERIALS: Five subjects who required a crown to restore a maxillary central incisor were selected. Two metal-ceramic crowns were fabricated for each incisor, 1 using the experimental procedure and 1 using the control method. The shade selection method to be used for the first and second crowns was randomly assigned. The duration of each procedure was recorded. Each restoration was tried-in in a double-blind manner and evaluated for its level of match to adjacent teeth using modified Ryge criteria. Data were analyzed within each subject using descriptive statistics and paired t test (alpha = .05). RESULTS: In 40% of the cases, both procedures did equally well. In the remaining 60% of the cases the control procedure (two-thirds of the cases) performed better than the experimental procedure (one-third of the cases). Duration of the control procedure was 14.4 +/- 5 minutes, and the experimental procedure was 5.2 +/- 3.3 minutes. A paired t test showed the difference was significant (P = .0045). CONCLUSION: The level of matching of crowns fabricated with the ShadeScan system was not different from crowns fabricated using the control. However, it took significantly less time to record the shade with the ShadeScan system.

Color↗