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.

Rat peri-implant soft tissue specifically expressed CXCL2 on titanium implant during wound healing.

Many of genes specifically expressed in peri-implant soft tissue (PIST) selected by microarray analysis are involved in the inflammatory response. This study investigated the gene expression and localization of PIST-specific inflammatory markers in PIST during wound healing. Pure titanium implants were implanted into the rat upper mandibular socket to create PIST. Samples were harvested from PIST as an experimental group, and tooth extracted area of oral mucosa tissue (OMT) and healthy periodontal tissue (PT) as control groups. The gene expressions of four standard inflammatory markers and nine PIST-specific inflammatory markers including chemokine (C-X-C motif) ligand 2 (CXCL2) during wound healing were examined. Immunoreactions of CXCL2 and immune cells in PIST and control tissues were compared. During wound healing, gene expression of PIST-specific inflammatory markers was higher in PIST than in OMT (p < .05), but there were no significant differences in the expression of standard inflammatory markers. The molecule CXCL2 was expressed locally at the implant-connective tissue interface, and localization of immune cells closely matched the CXCL2 expression pattern. In PIST, seven of PIST-specific inflammatory markers were expressed specifically and strongly during wound healing and their expression was maintained until the end of healing. Furthermore, CXCL2 expression was due to the creation of the implant-connective tissue interface, and it established a unique defense mechanism in PIST that was not apparent in OMT or PT.

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.

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.

Adhesion of streptococci to titanium and zirconia.

The purpose of this study was to evaluate the adherence of streptococci to disks of titanium (commercially pure titanium: CpTi) and zirconia (tetragonal zirconia polycrystals: TZP). CpTi and yttria-stabilized TZP disks with a mirror-polished surface were used as specimens. The arithmetic mean surface roughness (Ra and Sa) and the surface wettability of the experimental specimens were measured. For analyzing the outermost layer of the experimental specimens, X-ray photoelectron spectroscopy (XPS) analysis was performed. Streptococcus sanguinis, S. gordonii, S. oralis, and S. mutans were used as streptococcal bacterial strains. These bacterial cultures were grown for 24 h on CpTi and TZP. The number of bacterial adhesions was estimated using an ATP-bioluminescent assay, and scanning electron microscope (SEM) observation of the adhered bacterial specimens was performed. No significant differences in surface roughness or wettability were found between CpTi and TZP. In XPS analyses, outermost layer of CpTi included Ti0 and Ti4+, and outermost layer of TZP included Zr4+. In the cell adhesion assay, the adherences of S. sanguinis, S. gordonii, and S. oralis to TZP were significantly lower than those to CpTi (p < 0.05); however, significant difference was not observed for S. mutans among the specimens. The adherence to CpTi and TZP of S. mutans was significantly lower than that of S. sanguinis, S. gordonii, and S. oralis. These results were confirmed by SEM. S. sanguinis, S. gordonii, and S. oralis adhered less to TZP than to CpTi, but the adherence of S. mutans was similar to both surfaces. S. mutans was less adherent compare with the other streptococci tested in those specimens.

The characteristic regulation of gene expression Lbp and Sod3 in peri-implant connective tissue of rats.

The aim of this study was to investigate the characteristic gene expression profile and localization of peri-implant connective tissue (PICT) compared with those of periodontal connective tissue (PCT) and oral mucosal connective tissue (OMCT). Upper first molar of 5-week-old rats were extracted and titanium implant were placed for PICT group. PCT and OMCT were used as control. Laser microdissected connective tissue at 4 weeks used for microarray analysis. The expression and localization of selected genes were confirmed by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. Approximately, 1000 genes of upregulated and downregulated in PICT compared with PCT and OMCT were recognized. Based on the results of microarray analysis and qRT-PCR were demonstrated lipopolysaccharide binding protein (Lbp) as a specific upregulated gene and superoxide dismutase 3 (Sod3) as a specific downregulated gene in PICT. Immunoreaction of LBP and F4/80 as macrophage marker localized to subepithelial and implant facing connective tissue in PICT. SOD3 expression was not observed in PICT, reactive oxygen species, a target of superoxide dismutase, was strongly and locally expressed in all three tissues. Our data suggested that the upregulation of Lbp and downregulation of Sod3 are as characteristic gene expression pattern in PICT.

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.

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.

Implant-supported Prostheses in Patient with Sjögren's Syndrome: Clinical Report with 3-year Follow-up.

Sjögren's syndrome (SS), an autoimmune disorder, affects the exocrine glands, including the lacrimal and salivary glands. It is characterized by symptoms of dry eye and dry mouth. As secretion of saliva decreases, patients with SS experience rampant caries, pain in the oral mucosa, inflammation and hardening of the salivary glands, abnormal taste, dysphagia, and loss of teeth earlier than healthy individuals. A removable partial denture is often used as a prosthesis after tooth loss. Compromised salivary lubrication, however, can produce traumatic ulceration of the mucosa, making use of a removable prosthesis in SS patients painful. In such cases, a dental implant is likely to be requested as an alternative. This report describes dental implant treatment in an SS patient, a 50-year-old woman who presented with the chief complaint of masticatory dysfunction and pain due to a removable partial denture. Eight implants were placed in the maxillary and mandibular first molar tooth and second molar tooth regions. Following a 4-month non-loading period, second-stage surgery and provisional restoration with a screwretained implant temporary crown were performed. Screw-retained superstructures were fitted by means of a customized titanium abutment and zirconia crown as the final restoration. No complications, including inflammation of peri-implant soft tissue or resorption of peri-implant bone, were observed at 3 years following placement of the superstructures.

The genes Scgb1a1, Lpo and Gbp2 characteristically expressed in peri-implant epithelium of rats.

OBJECTIVES: The peri-implant epithelium (PIE) plays an important role in the prevention against initial stage of inflammation. To minimize the risk of peri-implantitis, it is necessary to understand the biological characteristics of the PIE. The aim of this study was to investigate the characteristic gene expression profile of PIE as compared to junctional epithelium (JE) using laser microdissection and microarray analysis. METHODS: Left upper first molars of 4-week-old rat were extracted, and titanium alloy implants were placed. Four weeks after surgery, samples were harvested by laser microdissection, and total RNA samples were isolated. Comprehensive analyses of genes expressed in the JE and PIE were performed using microarray analysis. Confirmation of the differential expression of selected genes was performed by quantitative real-time polymerase chain reaction and immunohistochemistry. RESULTS: The microarray analysis showed that 712 genes were more than twofold change upregulated in the PIE compared with the JE. Genes Scgb1a1 were significantly upregulated more than 19.1-fold, Lpo more than 19.0-fold, and Gbp2 more than 8.9-fold, in the PIE (P < 0.01). Immunohistochemical localization of SCGB1A1, LPO, and GBP2 was observed in PIE. CONCLUSION: The present results suggested that genes Scgb1a1, Lpo, and Gbp2 are characteristically expressed in the PIE.

Comparison of Gene Expression in Peri-implant Soft Tissue and Oral Mucosal Tissue by Microarray Analysis.

PURPOSE: Implant placement entails disruption of the epithelial continuity, which can lead to various complications. Therefore, the area of mucosal penetration is of particular interest clinically. The goal of the present study was to compare gene expression in peri-implant soft tissue (PIST) with that in oral mucosal tissue (OMT) using microarray analysis, and to investigate which genes were specifically expressed in PIST. MATERIALS AND METHODS: The bilateral upper first molars were extracted from 4-week-old rats and titanium alloy implants placed only in the left-side extraction sockets. Four weeks after surgery, samples were harvested from the left-side PIST and right-side OMT and total RNA samples isolated. Microarray analysis was used to compare gene expression in PIST and OMT, which was then confirmed using quantitative real-time polymerase chain reaction. Immunohistochemical staining was also performed to confirm protein level expression. RESULTS: The number of genes expressed with more than a twofold change in PIST compared with OMT was 1,102, of which 750 genes were upregulated and 352 genes were downregulated. The messenger RNA (mRNA) expression of three selected genes-Ceacam1, Ifitm1, and MUC4-were more significantly expressed in PIST than in OMT(P < .01). Immunohistochemical localization of CEACAM1, IFITM1, and MUC4 was observed in PIST, but no immunoreaction was recognized in OMT. CONCLUSION: The result of microarray analysis showed that, because of implant placement, 750 genes were upregulated in PIST compared with OMT. CEACAM1, IFITM1, and MUC4 were specifically upregulated in PIST.