Full-arch restoration with the NEXUS IOS® system: A retrospective clinical evaluation of 37 restorations after a one year of follow-up.

OBJECTIVES: Report the results with a novel workflow of digital restoration for completely edentulous patients with implant supported full arch fixed dental prostheses (ISFDP). METHODS: This multicenter retrospective clinical study was based on the evaluation from a cohort of 29 patients restored with 37 ISFDP designed and manufactured from the data captured by a direct intraoral scan, using a novel full digital system (NEXUS IOS®, Osteon Medical, a Keystone Dental Group company, Melbourne, Australia). Data was collected over a 3-year period, in six different dental centers. This study reported on the clinical parameters including: precision of marginal fit, functional and aesthetic integration of Nexus ISFDP. All patients were followed for a period of one year post delivery. Implant survival, biologic and prosthetic complications were assessed, at one year. A statistical analysis was conducted. RESULTS: All 37 ISFDP were deemed clinically acceptable on insertion. Implant survival at one year was 100 %. The biologic and prosthetic complications were minimal during the follow-up period. CONCLUSIONS: ISFDP, designed and manufactured using the NEXUS IOS® system, are clinically acceptable, with a low incidence of complications at one year. Long-term clinical studies are needed. STATEMENT OF CLINICAL RELEVANCE: Within the limitations of this study (retrospective design, small patient sample, limited follow-up) the NEXUS IOS® system seems to represent a viable solution for the restoration of completely edentulous patients with ISFDP, in a full digital workflow.

Evaluation of human periimplant soft tissues around nonsubmerged machined standard and platform-switched abutments.

PURPOSE: This study evaluated the effect of the platform-switching phenomenon, the use of a smaller diameter abutment on a larger diameter implant platform. Clinical and histological outcomes of the periimplant mucosa around titanium abutments in a nonsubmerged implant were evaluated. MATERIALS AND METHODS: Ten healthy adult patients, ranging from 27 to 65 years, participated in the study. A minimum of 2 endosseous implants with immediate abutment connection was placed per patient, 1 conventional and 1 platform-switched abutment. All sites for implant placement had an adequate zone of keratinized mucosa before surgical intervention. RESULTS: No clinical signs of inflammation were observed in the periimplant soft tissue mucosa, and healing was uneventful throughout the study period. Histological findings showed abnormally thick stratified squamous epithelium for both groups with few inflammatory cells in the connective tissue and none on the surface of the epithelium. CONCLUSION: Histological findings for both conventional and platform-switched implant-abutment configurations showed a similar composition of the soft tissue. These findings were in direct agreement with previous studies.

A complete denture impression technique survey of postdoctoral prosthodontic programs in the United States.

PURPOSE: The purpose of the study was to survey program directors of postdoctoral prosthodontic programs in the United States regarding their programs' complete denture impression techniques. The key objectives of the survey were to identify the current trends in complete denture impression making and to determine which techniques and materials are taught in US postdoctoral prosthodontic programs. MATERIALS AND METHODS: An online survey was sent to all program directors of US postdoctoral prosthodontic programs. The survey comprised two sections: preliminary impressions and final impressions. The survey contained 22 questions that would take approximately 5 minutes to complete. All responses remained anonymous throughout the survey. RESULTS: The response rate for the survey was 87%. A majority of the programs did not separately border mold the tray prior to making the preliminary impressions (82%). The impression material of choice for the preliminary impression was irreversible hydrocolloid (88%). Selective pressure was the predominantly used impression philosophy (80%). All programs border molded the custom tray, and 95% recorded the borders in sections. The material of choice for border molding the custom tray was modeling plastic impression compound (71%). The most commonly used impression material for the final impressions was polyvinylsiloxane (PVS) (42%), and the second most commonly used impression material was polysulphide (32%). The most common technique for locating the posterior palatal seal was marking intraorally and transferring onto the final impression (65%). Most programs routinely advised their patients not to wear their existing dentures for at least 24 hours before the final impressions were made (83%). CONCLUSIONS: Based on the results of this study, the following conclusions can be drawn: (1) The most commonly used material for the preliminary impression was irreversible hydrocolloid and for the final impression was PVS. (2) Modeling plastic impression compound was used by most programs to border mold the custom trays. (3) Selective pressure was the predominantly used impression philosophy. (4) A majority of the programs made a special consideration for excessive movable (flabby) tissue. (5) Most programs routinely advised their patients to not wear their existing dentures for at least 24 hours before the final impressions were made.

Resinous denture base fracture resistance: effects of thickness and teeth.

PURPOSE: Fracture is a frequent complication of resinous prostheses. The purpose of this study was to evaluate the effect of thickness on flexural strength of a resinous prosthesis containing a prosthetic tooth. MATERIALS AND METHODS: Beam-shaped specimens 65-mm long, 12-mm wide, and 1, 2, 3, 4, or 6 mm in thickness were made from high-impact strength polymethyl methacrylate denture base material, each containing a resin-based molar prosthetic tooth at the center of the beam. A group of 3-mm-thick specimens without a prosthetic tooth (n = 7) were also made. Specimens were aged artificially, loaded in three-point flexure, examined fractographically, and analyzed. RESULTS: The 1- and 2-mm-thick beams underwent considerable deformation at low loads. Maximum loads varied considerably from 0.6 kg (1-mm beams) to 38 kg (6-mm beams). The 3-, 4-, and 6-mm beam groups all underwent brittle fracture, with mean relative flexural strengths of approximately 73 MPa. Denture teeth reduced the relative flexural strength of resin beams by 0.7 x. Fracture initiation sites were generally at tiny surface defects, but did not directly involve denture teeth. Denture resin fracture toughness was 3.2 MPa m1/2, and modulus of rupture was 104 MPa. CONCLUSION: Denture teeth substantially decreased the strength of resinous beams. Increased thickness markedly increased the load-bearing capacity of resinous beams containing denture teeth. Beams less than 2 mm in thickness with denture teeth were weakened substantially more than comparable beams of 2 mm or more in thickness. Surface finish was of critical importance. Fracture toughness was calculated fractographically, facilitating future forensic examination of clinically failed resinous prostheses.

Interim prosthetic phase of multidisciplinary management of cleidocranial dysplasia: "the Bronx Approach".

This case report presents treatment of two patients with the usual characteristics of Cleidocranial Dysostosis. A multidisciplinary approach using the disciplines of prosthodontics, orthodontics, and oral surgery was effected. Exfoliation of the patient's deciduous teeth and failure of permanent anterior tooth eruption led to emotional, social, and self-esteem issues in both patients. Due to the psychosocial issues confronting these two patients, esthetics was addressed prior to active intervention with orthodontics and after some surgical intervention. The use of two interim overdenture prostheses with magnetic retention is described.

A technique for retrieval of cement-retained implant-supported prostheses.

Predictable retrievability of cement-retained prostheses has been a clinical concern. This article presents a technique that describes an implant restoration design which will allow predictable removal of cement-retained implant-supported prostheses.

Fatigue testing of laser treated endosseous implants with an internal trilobe connection.

This study investigated the effect of laser treatment on the fatigue resistance of a 3.5-mm diameter implant with an internal trilobe connection. Twenty two implants were embedded into acrylic resin blocks. Half the specimens were used as control group, and the other half were laser treated circumferentially around the 1.5-mm polished collar with argon shielding. Implants were fatigue tested using a step-stress accelerated lifetime test in a servo-hydraulic test machine. Despite the trend pointing towards higher fatigue resistance of laser treated specimens versus controls, step-stress analysis did not determine significant differences in the fatigue lifetimes.

A digital radiographic artifact: A clinical report.

Digital dental radiographic imaging is considered to be as diagnostically accurate as conventional film-based radiography. In addition, many digital radiographic systems offer various image enhancements that may aid in image interpretation. However, neither type of radiographic imaging technique perfectly correlates radiographic diagnoses with clinical findings. Moreover, visual digital enhancements may provide information that is diagnostically misleading. This report presents a completed patient treatment evaluation with both enhanced and unenhanced digital radiography. The outcome suggests that clinicians should be careful with the interpretation of digital radiographic images, as this can potentially result in false-positive diagnoses.

Prosthodontic management of sulcoplasty and sialodochoplasty with a conforming surgical stent.

This clinical report describes the management of chronic, proliferative inflammatory epithelial and fibrous hyperplasia following loss of a mandibular implant-retained prosthesis. A classic surgical technique was used. The patient was referred to the oral surgeon for sialodochoplasty and sulcoplasty. With a combination of surgery and prosthodontic management with a conforming surgical stent, a satisfactory denture foundation was created, allowing for fabrication of an implant-retained definitive prosthesis.

Inactivation of soybean trypsin inhibitors and lipoxygenase by high-pressure processing.

Trypsin inhibitors (TIA), one of the antinutritional factors of soy milk, are usually inactivated by heat treatment. In the current study, high-pressure processing (HPP) was evaluated as an alternative for the inactivation of TIA in soy milk. Moreover, the effect of HPP on lipoxygenase (LOX) in whole soybeans and soy milk was studied. For complete LOX inactivation either very high pressures (800 MPa) or a combined temperature/pressure treatment (60 degrees C/600 MPa) was needed. Pressure inactivation of TIA was possible only in combination with elevated temperatures. For TIA inactivation, three process parameters, temperature, time, and pressure, were optimized using experimental design and response surface methodology. A 90% TIA inactivation with treatment times of <2 min can be reached at temperatures between 77 and 90 degrees C and pressures between 750 and 525 MPa.