Dimensional changes of buccal bone in the edentulous maxilla with telescopic-retained implant-supported fixed dental prostheses.

STATEMENT OF PROBLEM: The buccal bone in an edentulous maxilla loses thickness over time because of physiological changes. However, the dimensional changes of the buccal bone in an edentulous maxilla with an implant-supported fixed dental prosthesis are unknown. PURPOSE: The purpose of this retrospective clinical study was to evaluate cone beam computed tomography (CBCT) images of the dimensional changes of the buccal bone in edentulous maxillae with complete arch telescopic-retained implant-supported fixed dental prostheses (CTI-FDPs) after 6 years by using a professional retrieval system. MATERIAL AND METHODS: This study included 17 participants with edentulous maxillae who had been provided with CTI-FDP with 121 taper joint implants. A three-dimensional radiographic analysis by using CBCT was performed at implant insertion (0 years) and after 6 years. Vertical and horizontal bone measurement values were evaluated. During horizontal bone thickness measurement, 4 different levels, 0, 2, 4, and 6 mm apical to the implant shoulder, were evaluated as bone value (BV)0mm, BV2mm, BV4mm, and BV6mm, respectively. The BVs were compared with the Wilcoxon signed-rank test and Kruskal-Wallis test (α=.05). In addition, the Spearman rank correlation coefficient was used to identify 0yBV factors that influence the 6yBVs. A nonlinear regression analysis was used to clarify the slopes of 0yBVs and 6yBV0mm. RESULTS: Significant decreases in vertical and horizontal BVs were found between 0 years and 6 years (P<.05). However, no significant difference was observed in bone loss at 6 years at any of the vertical and horizontal measurement points (P≥.05). When 0yBVs related to 6yBV0mm were analyzed, 0yBV0mm and 0yBV2mm showed strong correlations with 6yBV0mm (|r|≥.7). In the regression analysis, a 0yBV0mm of 0.58 mm and 0yBV2mm of 0.78 mm could be critical factors associated with a 6yBV0mm of 0 mm. A 6yBV0mm of 0yBV0mm more than 0.58 mm was significantly higher than a 6yBV0mm of 0yBV0mm less than 0.58 mm (P<.001). Moreover, a 6yBV0mm of 0yBV2mm more than 0.78 mm was significantly higher than a 6yBV0mm of 0yBV2mm less than 0.78 mm (P<.001). CONCLUSIONS: The buccal bone in an edentulous maxilla with fixed implant-supported prostheses lost significant vertical and horizontal bone thicknesses after 6 years. At implant insertion, both a 0.58-mm buccal bone on the platform and a 0.78-mm buccal bone at 2 mm apical to the implant shoulder are necessary for longer term maintenance of bone on the platform of implants specifically supporting CTI-FDPs.

Overcoming Complications with Implants in the Esthetic Zone: An Innovative Approach.

Owing to the satisfactory esthetic and functional outcomes of implant surgery for the anterior teeth, some dentists consider it the gold standard treatment. However, the risk of developing peri-implantitis is positively associated with the long-term use of the implant. This necessitates the development of an implant design that reduces the risk of peri-implantitis, especially considering the long-term use of implants in young patients. This case report describes a new approach for an implant surgery using a two-stage implant in a 28-year-old woman. Her clinical course was satisfactory during the 4-year postoperative follow-up period; no inflammation was noted in the surrounding tissues. The two-stage implants allow for the removal of an implant body from an infected area and its replacement with a new abutment if peri-implantitis develops in the future.

Implant Treatment in Patient with Periodontitis: A Case Report with 13-year Follow-up.

This report describes long-term implant treatment in a patient with chronic periodontitis. The patient was a 59-year-old man who attended our facility requesting a dental implant. An initial examination revealed generalized gingival inflammation and subgingival calculus. Clinical examination revealed 55.3% of sites with a probing depth (PD) of >4 mm and 41.3% of sites with bleeding on probing. Radiographic examination revealed vertical bone resorption in #23, #33, #33, #35, and #47. Initial periodontal therapy consisting of plaque control, scaling and root planing, and tooth extraction was subsequently performed based on a clinical diagnosis of severe chronic periodontitis. Open flap debridement was performed for teeth with a PD >5 mm (#21, #22, #23, 333, #34, #35 and #47). After confirming the stability of the periodontal tissue, 3 implants were first placed in the maxilla (#25, #26, and #27). Final prostheses comprising a screw retaining-type implant superstructure were then placed (#25, #26, and 327). Following reevaluation, the patient was placed on supportive periodontal therapy. At 15 years after the first visit, the periodontal and implant conditions have remained stable. These results indicate that periodontal treatment before implantation and subsequent maintenance yield a clinically favorable and long-lasting outcome.

Marginal bone loss and the risk indicators of fixed screw-retained implant-supported prostheses and fixed telescopic-retained implant-supported prostheses in full arch: A retrospective case-control study.

OBJECTIVES: This study compared full-arch screw-retained implant-supported fixed dental prostheses (FSI-FDPs) and full-arch telescopic-retained implant-supported fixed dental prostheses with a professional retrieval system (FTI-FDPs) on marginal bone loss (MBL), the risk indicators and peri-implantitis rate after 7-13 years. MATERIAL AND METHODS: Sixty five edentulous patients were treated with 86 prostheses and 592 implants. The FSI-FDP group comprised 26 patients (32 prostheses, 202 implants), and the FTI-FDP group comprised 39 patients (54 prostheses, 390 implants). MBL and the risk indicators of MBL ≥1 mm were assessed. Peri-implantitis rates at 13 years were also calculated. RESULTS: Full-arch screw-retained implant-supported fixed dental prostheses and FTI-FDP implants exhibited comparable mean MBLs of 0.60 ± 0.51 and 0.41 ± 1.03 mm, respectively. MBL ≥1 mm was noted for 25% of FSI-FDP implants and 6.9% of FTI-FDP implants. Superstructure-abutment connection (screw retention:FSI-FDPs >telescopic retention:FTI-FDPs) and implant-abutment connection (External butt joint, Internal butt joint >Morse taper joint) were associated with MBL ≥1 mm. Peri-implantitis rates at the implant level were 3.99% (95%CI = 3.93-20.5) in FSI-FDP group and 3.85% (95%CI = 3.85-34.3) in FTI-FDP group with no significance. CONCLUSIONS: It was concluded that FSI-FDP and FTI-FDP implants exhibited comparable MBL; however, the risk of MBL ≥1 mm in FTI-FDPs was lower than in FSI-FDPs. Besides, implant-abutment connection was the risk indicator of MBL ≥1 mm. In peri-implantitis rate, FSI-FDPs and FTI-FDPs behave similarly.

Clinical evaluation of full-arch screw-retained implant-supported fixed prostheses and full-arch telescopic-retained implant-supported fixed prostheses: A 5-12 year follow-up retrospective study.

OBJECTIVE: To assess the prostheses and implants survival rate and peri-implantitis rate in edentulous patients treated with full-arch screw-retained implant-supported fixed dental prostheses (FSIFDPs) and full-arch telescopic-retained implant-supported fixed dental prostheses (FTIFDPs) over an observation period of at least 5 years. MATERIALS AND METHODS: From 2004 to 2012, 696 implants were inserted into 78 patients with 102 prostheses. The FSIFDP group comprised 31 patients (37 prostheses, 232 implants), whereas the FTIFDP group comprised 47 patients (65 prostheses, 464 implants). Prosthesis and implant estimated cumulative survival rates (ECSR) and estimated cumulative peri-implantitis rates (ECPR) were assessed. The follow-up period was 5-12 years. Kaplan-Meier survival curves with the log-rank test were used to evaluate outcomes. RESULTS: The 12-year prosthesis ECSR was 96.8% (95% CI: 79.2-99.5, 36/37 prostheses) in the FSIFDP group and 96.4% (95% CI: 86.3-99.1, 63/65 prostheses) in the FTIFDP group, whereas the 12-year implant ECSR was 99.5% (95% CI: 96.4-99.9, 231/232 implants) in the FSIFDP group and 98.7% (95% CI: 96.9-99.5, 459/464 implants) in the FTIFDP group. The 12-year ECPR at the prosthesis level was 12.8% (95% CI: 12.7-47.6, 4/37 prostheses) in the FSIFDP group and 12.8% (95% CI: 11.4-24.1, 6/65 prostheses) in the FTIFDP group. The 12-year ECPR at the implant level was 4.4% (95% CI: 4.3-23.0, 6/232 implants) in the FSIFDP group and 2.2% (95% CI: 2.0-12.3, 7/464 implants) in the FTIFDP group. CONCLUSION: FTIFDPs have clinical results comparable to those of FSIFDPs. Therefore, FTIFDPs can be useful.

Full-Arch Implant-Supported Fixed Dental Prosthesis Retained by a Combination of Galvano-Telescopic Copings and Screws: A Clinical Report.

Full-arch screw-retained implant-supported fixed dental prostheses have a high long-term success rate and are considered the gold standard by many clinicians. However, accurate fabrication of a passive fit long-span prosthesis can be challenging. A novel intraoral adhesion method using galvano-telescopic copings was proposed as a way of improving prosthetic fit for edentulous patients. This report describes the treatment of a 74-year-old female with a full-arch implant-supported dental prosthesis, supported by a combination of galvano-telescopic copings and screws to prevent retention loss. Four years have passed since this superstructure was placed, during this time she exhibited a good clinical course with no inflammation noted in surrounding tissues. Treatment with an implant-supported fixed dental prosthesis, retained by a combination of galvano-telescopic copings and screws, can be a useful alternative treatment for edentulous patients.

Effect of side-chain carbonyl groups on the interface of vinyl polymers with water.

The nature of the polymer-water interface in the poly(methyl 2-propenyl ether) (PMPE)-water model system is investigated by sum-frequency generation spectroscopy, which at the moment gives the best depth resolution among available techniques. PMPE, synthesized via living cationic polymerization, is structurally similar to poly(methyl methacrylate) (PMMA) except for lacking a carbonyl group. We here probe the polymer local conformation as well as the aggregation states of water at the interface. Comparing the results of our measurements to the PMMA-water system, the effect of a carbonyl group on the water structure at the interface is discussed. This knowledge should be crucial to the design and construction of highly functionalized polymer interfaces for bioapplications.

Block versus random amphiphilic copolymers as antibacterial agents.

We examined the antibacterial and hemolytic activities in a series of amphiphilic block and random copolymers of poly(vinyl ether) derivatives prepared by base-assisting living cationic polymerization. Block and random amphiphilic copolymers with similar monomer compositions showed the same level of activity against Escherichia coli . However, the block copolymers are much less hemolytic compared to the highly hemolytic random copolymers. These results indicate that the amphiphilic copolymer structure is a key determinant of activity. Furthermore, the block copolymers induced dye leakage from lipid vesicles consisting of E. coli -type lipids, but not mammalian lipids, while the random copolymers disrupted both types of vesicles. In addition, both copolymers displayed bactericidal and hemolytic activities at concentrations 1 or 2 orders of magnitude lower than their critical (intermolecular) aggregation concentrations (CACs), as determined by light scattering measurements. This suggests that polymer aggregation or macromolecular assembly is not a requisite for the antibacterial activity and selectivity against bacteria over human red blood cells (RBCs). We speculate that different single-chain conformations between the block and random copolymers play an important role in the antibacterial action and underlying antibacterial mechanisms.

Effects of 2% sodium fluoride solution on the prevention of streptococcal adhesion to titanium and zirconia surfaces.

Streptococci are associated with dental plaque formation as the early-colonizing bacteria that adhere to titanium (CpTi) and zirconia (TZP) implant abutment surfaces. Effective prevention of peri-implantitis may be possible by removing streptococci as target. This study aimed to evaluate the effects of 2% NaF on the prevention of streptococcal adhesion to CpTi and TZP. After immersion in 2% NaF for 90 min, surface characterization of mirror-polished CpTi and TZP disks were assesed using XPS, EPMA, and SEM. S. sanguinis, S. gordonii, and S. oralis were used as the streptococcal bacterial strains. After 24 h culture, bacterial adhesion was evaluated using an ATP-bioluminescent assay and SEM. In XPS, EPMA, and SEM analyses, fluoride was detected on the CpTi and TZP surfaces after 2% NaF immersion with no signs of localization, and no corrosion on the CpTi disks. Based on the adhesion assay, the adherences of S. sanguinis, S. gordonii, and S. oralis were significantly lower with NaF than without NaF in CpTi (p = 0.005, 0.001, and 0.001, respectively) and TZP (p = 0.003, 0.002, and 0.001). This was also confirmed by SEM. In conclusion, 2% NaF reduced the adhesion of streptococci to the CpTi and TZP surfaces.

Clinical evaluation of periodontal pathogen levels by real-time polymerase chain reaction in peri-implantitis patients.

OBJECTIVE: The mechanisms underlying the onset and progression of peri-implantitis are similar to those of periodontitis, and the causative bacteria are believed to similar. Previous studies support an association between peri-implantitis and periodontal pathogen. Thus, we investigated the bacterial flora of peri-implantitis patients in comparison to those of healthy implant and periodontitis patients. MATERIALS AND METHODS: In total, 70 patients visiting Tokyo Dental College Chiba Hospital were divided into four groups: healthy, periodontitis, healthy implant, and peri-implantitis. For each group, the following five periodontal pathogens were detected using real-time polymerase chain reaction: Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, and Prevotella intermedia. RESULTS: The average copy number of total bacteria was significantly higher in the periodontitis group than in the other groups. P. gingivalis was detected in the periodontitis and peri-implantitis groups at levels as high as 18.92% and 12.29%, respectively, and P. intermedia was found in the peri-implantitis group at a rate of 2.06%. Nevertheless, periodontal pathogens were generally detected at lower levels in the peri-implantitis group than in the periodontitis group. CONCLUSION: We found lower bacterial counts in the peri-implantitis group relative to the periodontitis group. Our results suggest that the peri-implant tissue is less resistant to bacteria, so even a small number of bacteria can be a risk factor for peri-implantitis and the causative agent of peri-implantitis can be bacteria other than periodontal pathogen.