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Purpose: The aim of this study was to evaluate plaque accumulation and peri-implant tissue response adjacent to machined and dual acid-etched (DAE) titanium implant surfaces. Materials and Methods: Two types of implants were used-control implants with a DAE surface in their apical portion and a machined coronal part, and test implants with a DAE surface throughout their entire length. A total of 10 sets of implants were placed in the posterior quadrants of eight patients, with at least 2 implants (1 control and 1 test implant) placed in each site. Machined healing abutments were placed on the control implants and DAE-surfaced healing abutments on the test implants. Plaque Index and bleeding on probing (BOP) were recorded together with histologic and microbiologic analyses of the peri-implant tissues. The healing abutments underwent a scanning electron microscope scan at 5 months postsurgery. Standardized radiographs were also taken at the time of implant placement and 3, 6, and 12 months postsurgery. Results: DAE surfaces accumulated more plaque than machined surfaces (P < .0006) and the plaque was assessed as more difficult to remove (P < .0143). No histologic abnormalities were seen and the test implants showed significantly lower crestal bone resorption than the control (P < .0174). Conclusion: DAE healing abutments showed an increased plaque accumulation, but no significant BOP differences or histologic analyses were found between test and control sites. The test implants showed less interproximal bone resorption than the control ones at the end of a 1-year follow-up evaluation. [ABSTRACT FROM AUTHOR]

Many clinical studies have reported high survival rates for tilted implants. However, tilted implants transmit increased stress to bone when compared to vertically placed implants. Theoretical (computer-based), laboratory, and clinical studies are warranted to effectively address this issue. In this study, a 3-dimensional finite element analysis was performed to analyze the stress values surrounding tilted versus vertical implants. The results revealed laboratory and biomechanical evidence that distal tilting of implants, splinted in full fixed prostheses without cantilevers, reduced the amount of stress generated around the peri-implant bone when compared to the levels of stress seen in peri-implant bone with vertical implants and cantilevered segments in similar full fixed prostheses. [ABSTRACT FROM AUTHOR]

Purpose: This study describes a mechanical chewing simulator that is able to reproduce mandibular movements in 3 dimensions and the forces exerted during mastication. The aim of this work was to validate the described device, which can be used to test the ability of different restorative materials to withstand stress. Materials and Methods: To validate the masticatory robot, 5 identical samples for each of 3 different restorative materials (an acrylic resin, a composite resin, and a glass ceramic) were created. Each sample underwent 5 minutes of chewing in the robot. The forces transmitted to the simulated peri-implant bone were collected. Two-way analysis of variance was used to evaluate the results. Results: There were significant differences between the materials, and internal comparisons also showed significant differences (P < .0001). Conclusion: The different elastic moduli of the restorative materials significantly affected stress transmission at the simulated bone-implant interface, and the masticatory robot was able to identify this difference. The very low levels of variation confirm the precision of the machine during data collection and validate the reliability of the method, showing effective repeatability of the tests. [ABSTRACT FROM AUTHOR]

Purpose: This study was conducted to measure, in vitro, the chewing load forces transmitted through crowns made of different prosthetic restorative materials onto dental implants. Materials and Methods: A masticatory robot capable of reproducing the mandibular movements and the forces exerted during chewing was used. The forces transmitted to the simulated peri-implant bone during the robot mastication were analyzed using four different occlusal materials three resin composites and one glass ceramic crown. Results: The ceramic crowns transmitted significantly greater forces (up to +63.06%, P < .0001) than the composite crowns tested. Conclusion: Composite crowns are better able to absorb shock from occlusal forces than crowns made of ceramic material. [ABSTRACT FROM AUTHOR]

Frameworks made of carbon fibre-reinforced composites (CFRC) seem to be a viable alternative to traditional metal frameworks in implant prosthodontics. CFRC provide stiffness, rigidity and optimal biocompatibility. The aim of the present prospective study was to compare carbon fibre frameworks versus metal frameworks used to rigidly splint implants in full-arch immediate loading rehabilitations. Forty-two patients ( test group) were rehabilitated with full-arch immediate loading rehabilitations of the upper jaw (total: 170 implants) following the Columbus Bridge Protocol with four to six implants with distal tilted implants. All patients were treated with resin screw-retained full-arch prostheses endowed with carbon fibre frameworks. The mean follow-up was 22 months (range: 18-24). Differences in the absolute change of bone resorption over time between the two implant sides (mesial and distal) were assessed performing a Mann-Whitney U-test. The outcomes were statistically compared with those of patients rehabilitated following the same protocol but using metal frameworks ( control group: 34 patients with 163 implants - data reported in Tealdo, Menini, Bevilacqua, Pera, Pesce, Signori, Pera, Int J Prosthodont, 27, 2014, 207). Ten implants failed in the control group (6·1%); none failed in the test group ( P = 0·002). A statistically significant difference in the absolute change of bone resorption around the implants was found between the two groups ( P = 0·004), with greater mean peri-implant bone resorption in the control group (1 mm) compared to the test group (0·8 mm). Carbon fibre frameworks may be considered as a viable alternative to the metal ones and showed less marginal bone loss around implants and a greater implant survival rate during the observation period. [ABSTRACT FROM AUTHOR]

This work evaluates whether isolation and toxicity of subgingival Staphylococcus aureus strains correlate with progression of periodontal lesions and whether isolates are characterized by a specific genomic background. The study involved 165 subjects affected by generalized aggressive periodontitis. Three sets of samples of supragingival and subgingival plaque were obtained at 45-day intervals from active and non-active sites, to detect S. aureus. Susceptibility to antibiotics, the presence of 17 genes, genomic restriction profiles and multilocus sequence typing (MLST) were performed to characterize all isolates. S. aureus was detected in 37.6% of the subjects. Subgingival colonization rates were 66.1% and 12.9% for active and non-active sites, respectively (P<0.01). Supragingival and subgingival isolates were shown to be distinct by molecular genotyping and DNA fingerprint analysis. MLST showed that isolates were not genetically related and no sequence type was predominant in any of the two locations. These data demonstrate that S. aureus is associated with the progression of aggressive periodontitis and that a specific set of characters is necessary for the bacterium to colonize subgingival sites. Comparative analysis of genomic structure and genetic-related data suggest that the periodontal environment could promote genetic evolution of strains. [ABSTRACT FROM AUTHOR]

Tilted implants have been proposed as an alternative to traditional protocols in the rehabilitation of edentulous maxillae. The aim of this meta-analysis was to evaluate the outcomes of upright and tilted implants supporting full-arch fixed dentures for the immediate rehabilitation of edentulous maxillae, after at least 1 year of function. An electronic search of databases and a hand search of relevant journals in oral implantology were performed according to PRISMA guidelines through August, 2011. The literature search yielded 1,069 articles. Eleven articles were available for analysis. A total of 1,623 implants (778 tilted, 845 upright) were inserted into the maxillae of 324 patients. Seventeen tilted (2.19%) and 16 upright implants (1.89%) failed during the first year. No significant difference in failure rate was found between tilted and upright implants (p value = 0.52). Marginal bone level results were obtained from 6 studies. A non-significant mean difference between tilted and upright implants was found with regard to bone loss. Tilted implants demonstrated a favorable short-term prognosis in full-arch immediate loading rehabilitations of the maxillae. Randomized long-term trials are needed to better elucidate long-term success of tilted vs. upright-positioned implants. [ABSTRACT FROM PUBLISHER]

Abstract: The aim of this paper is to describe a technique for sinus floor augmentation with a 1-step crestal approach where the residual bone is ≤7.5mm. 36 implants were installed in 25 patients in the atrophic posterior maxilla immediately after sinus floor elevation. Sinus floor elevation was performed with a crestal approach using either osteotomes and burs or piezosurgery. Standardized intraoral radiographs were taken prior to surgery and 1 year after surgery. The mean residual bone height was 5.61mm (range 3–7.5mm). The mean gain of sinus elevation was 6.78mm (range 3.5–10mm) at 1 year after surgery. Two patients dropped out of the study. Of the 23 patients completing the study, one implant failed, whilst the remaining 33 implants were stable 12 months after surgery (cumulative survival rate 97%). A statistically significantly higher bone height was achieved with tapered implants compared with cylindrical implants (P <0.05). No statistically significant differences were found in bone level using osteotomes or piezosurgery. Piezosurgery was considered to provide less discomfort for the patient and greater convenience for the surgeon. [Copyright &y& Elsevier]

STATEMENT OF PROBLEM: Immediate occlusal loading of dental implants in the edentulous mandible has proven to be an effective, reliable, and predictable procedure. There is little long-term data available on similar treatments in the edentulous maxilla. PURPOSE: The purpose of this study was to evaluate the 12-month implant survival after immediate loading of 4 to 6 implants with fixed screw-retained prostheses in edentulous maxillae. MATERIAL AND METHODS: Twenty-one patients, edentulous or with remaining teeth to be extracted in the maxilla, received 4 to 6 implants (n=111). The patients were restored with screw-retained fixed provisional prostheses supported by palladium-alloy frameworks within 24 hours after surgery. Insertion torques for implants were at least 40 Ncm. Implants, grouped as tapered or cylindrical screws, were placed in healed bone or extraction sockets. Implants were also classified as either vertical or off-angle. Definitive prostheses were placed after a mean healing time of 18 weeks. Radiographic examinations were made at the time of placement of provisional prostheses and 12 months later. Between-groups bone resorption was compared using 2-way ANOVA (alpha=.05). RESULTS: The mean follow-up time for all of the patients was 20 months (range, 13 to 28 months). The cumulative implant survival rate at the 12-month follow-up visits (after surgery) was 92.8%; the prostheses survival rate was 100%. No significant differences were found between the survival of tapered or cylindrical screw-type implants placed in postextraction sockets versus those in healed edentulous sites or between vertical and off-angle placed implants. Eight implants failed during the first 3 months, 5 of which were the most distal implants. The mean reduction in marginal bone height over the 12-month observation period was 0.84 mm (CI 95%; 0.68-0.99 mm). CONCLUSIONS: In this study with 12-month follow-up, 4 to 6 implants were sufficient to successfully support fixed implant screw-retained prostheses in the edentulous maxillae of 21 patients. (J Prosthet Dent 2008;99:351-360). [ABSTRACT FROM AUTHOR]

Scalable models for both active and passive components are essential for the design of highly integrated fiber-optic physical layer ICs. This paper focuses on the various technology options available for 10 Gb/s and 40 Gb/s applications, on how their constituent components are modeled and what the characteristics and requirements are for the basic building blocks. As part of the technology comparison, an overview of the performance of leading edge Si CMOS, SiGe BiCMOS and III-V technologies is presented. Scalable models for SiGe HBTs and GaAs p-HEMTs are then compared with measured data for various device sizes. Inductors, varactors, transmission lines and isolation techniques on Si and III-V substrates are discussed next followed by technology-specific implementations of VCO and digital building blocks. Finally, Transimpedance Limiting Amplifier (TIALA) as well as laser and modulator driver designs in SiGe BiCMOS, InP HBT and GaAs pHEMT processes using scalable device models are illustrated for 10 and 40 Gb/s fiber-optics applications. [ABSTRACT FROM AUTHOR]

The aim of the present research was to measure in vitro the chewing load forces transmitted through crowns made of different prosthetic restorative materials onto the dental implant. A masticatory robot that is able to reproduce the mandibular movements and the forces exerted during mastication was used. The forces transmitted to the simulated periimplant bone during the robot mastication were analyzed, using different occlusal materials. Two-way analysis of variance (ANOVA) was used. The zirconia and the ceramic crowns transmitted significantly greater forces (p-value < 0.0001) than the other crowns tested. Dental materials with lower elastic modulus were better able to absorb shock from occlusal forces than more rigid materials. [ABSTRACT FROM AUTHOR]

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