Effects of the application of low-temperature atmospheric plasma on titanium implants on wound healing in peri-implant connective tissue in rats

PURPOSE

This study aimed to clarify the effects of surface modification of titanium (Ti) implants by low-temperature atmospheric pressure plasma treatment on wound healing and cell attachment for biological sealing in peri-implant soft tissue.

METHODS

Hydrophilization to a Ti disk using a handheld low-temperature atmospheric pressure plasma device was evaluated by a contact angle test and compared with an untreated group. In in vivo experiments, plasma-treated pure Ti implants using a handheld plasma device (experimental group: PL) and untreated implants (control group: Cont) were placed into the rat upper molar socket, and samples were harvested at 3, 7 and 14 days after surgery. Histological evaluation was performed to assess biological sealing, collagen- and cell adhesion-related gene expression by reverse transcription quantitative polymerase chain reaction, collagen fiber detection by Picrosirius Red staining, and immunohistochemistry for integrins.

RESULTS

In in vivo experiments, increased width of the peri-implant connective tissue (PICT) and suppression of epithelial down growth was observed in PL compared with Cont. In addition, high gene expression of types I and XII collagen at 7 days and acceleration of collagen maturation was recognized in PL. Strong immunoreaction of integrin α2, α5, and β1 was observed at the implant contact area of PICT in PL.

CONCLUSIONS

The handheld low-temperature atmospheric pressure plasma device provided hydrophilicity on the Ti surface and maintained the width of the contact area of PICT to the implant surface as a result of accelerated collagen maturation and fibroblast adhesion, compared to no plasma application.

Two Cases of Idiopathic Condylar Resorption Due to Temporomandibular Joint (TMJ) Osteoarthritis Remodeled by Different Treatment Modalities

Condylar resorption is a condition of progressive and significant mandibular head resorption. We treated two patients with condylar resorption caused by temporomandibular joint (TMJ) osteoarthritis. The first patient was a 22-year-old female at the time of the initial examination. She had a history of orthodontic treatment and came to the clinic with a number of symptoms, including difficulty opening the mouth. Idiopathic condylar resorption was diagnosed, an occlusal splint was placed for approximately one year, and the patient was followed up for 12 years. The second patient was a 20-year-old female who had completed non-extraction orthodontic treatment by the age of 17 years. She came to the clinic with esthetic issues, such as an anterior open bite. Implant anchor screws were placed in the alveolar bone of the anterior teeth and intermaxillary fixation was performed. Case 1 had 12 years of follow-up, with CT scan results showing remodeling of the condylar. Case 2 is expected to shorten treatment time. However, the CT scan showed remodeling and improvement in the chief complaint.

Subgingival titanium wire implantation induces weak inflammatory responses but does not promote substantial T cell activation

Titanium is a biocompatible material commonly used for dental treatments. However, the detailed mechanism underlying the weak biological activity of titanium has not been elucidated. We investigated both the inflammatory responses and T cell activation induced by solid titanium in the gingiva in mice. Both titanium and nickel wire implantation promoted neutrophil infiltration into the gingiva on day 2. Nickel, but not titanium, wire implantation enhanced proinflammatory cytokine expression and dendritic cell activity in gingival tissue by day 2. Nickel wire implantation enhanced the activity of T cells in draining lymph nodes on day 5. Moreover, T cell and neutrophil infiltration and elevated proinflammatory cytokine expression in the gingival tissue were still observed on day 5. However, no such augmented biological responses were observed after titanium wire implantation. These findings suggest that, unlike nickel, solid titanium does not induce sufficient inflammatory responses leading to T cell activation in gingival tissue.

The effect of scanning pathways on trueness and precision in full-arch optical impression

BACKGROUND

In this study, we investigated the effects of differences in scanning pathways during optical impression on the trueness and precision of full-arch impressions.

METHODS

Reference data were obtained using a laboratory scanner. All optical impressions were measured across the dental arch using TRIOS® 3 in four different pathways. The reference and optical impression data were superimposed using the best-fit method. The criteria for superimposition were based on the starting side of the dental arch (partial arch best-fit method, PB) and based on the full arch (full arch best-fit method, FB). The data were compared between the left and right molars (starting and ending sides). The scan deviations for trueness (n = 5) and precision (n = 10) were obtained for each group by calculating the root mean square (RMS) of the deviation at each measurement point. Visual observations using superimposed color map images revealed variations in trueness.

RESULTS

There were no significant differences in scanning time or amount of scan data between the four scanning pathways. Trueness did not differ significantly among the four pathways with respect to the starting and ending sides, regardless of the superimposition criteria. Precision with PB was significantly different between scanning pathways A and B, and pathways B and C for the starting sides, and between scanning pathways A and B, and pathways A and D for the ending sides. In contrast, there was no significant difference between the starting and ending side in pathways for FB. Regarding PB, color map images showed a large error range in the direction toward the molar radius for the occlusal surface and cervical regions on the ending sides.

CONCLUSION

Differences in the scanning pathways did not affect trueness, regardless of the superimposition criteria. On the other hand, differences in the scanning pathways affected the precision of the starting and ending sides with PB. Scanning pathways B and D were more precise on the starting and ending sides, respectively.

Regeneration of sensory nerve branches in extraction socket and surrounding alveolar bone in rat: immunohistochemical observation of the axon and myelin sheath changes

The purpose of this study was to investigate the process and derivation of the distribution of the sensory nerves that appear in the extraction socket and surrounding alveolar bone following tooth extraction. The right mandibular first molar of rats and periodontal ligament were extracted as a single mass, and the mandible was harvested after days 1, 3, 5, and 7 after extraction. Serial sections of 7 µm thickness were prepared for the proximal root (Section A), buccolingual root (Section B), and centrifugal root (Section C) of the first molar. H–E staining and immunohistochemical staining with anti-S100 antibody and anti-NF-L antibody were carried out. The presence of nerve fiber bundles in the blood clot was already evident on post-extraction day 3, and on post-extraction day 7. On day 3, the number of axons in Sections B and C had greatly decreased, indicating that, after extraction, the connection between peripheral nerve tissue and the trigeminal ganglion was temporarily markedly reduced in the region of the alveolar branch. Although the myelin sheaths were regenerating on day 5, the majority of the axons of the alveolar branches extending from the inferior alveolar nerve were seen to be extremely thin and scattered, despite their further regeneration. The above results suggest that the newly myelinated nerves are actually derived from the bone marrow to the extraction socket, so few nerves, rather than being derived from the alveolar branches that had innervated the extracted tooth.

Sintering distortion of monolithic zirconia in 4-unit fixed partial denture: Effect of layered structure and vertical milling area

Layered-type zirconia disks, which offer color gradation from enamel to cervical shade, have been employed in recent years to replicate the shades of natural teeth. The layered structure is effective at replicating colors and has helped popularize monolithic zirconia restorations. However, the sintering shrinkage of zirconia is very large; thus, controlling the sintering distortion is very important. Thus, the objective of this study was to determine the influence exerted by the layered structure of the zirconia disk and the vertical milling area on the sintering distortion. An experimental fixed partial denture (FPD) was designed based on a 4-unit monolithic zirconia FPD. A single-composition (SC)-type disk with no shade and a single-composition-layered (SCL)-type disk with shade gradation were selected for this study. In particular, three milling areas, the top end of the disk (area I), vertical center (area II), and bottom end of the disk (area III), were investigated. Moreover, the sintering distortions generated by the experimental FPDs were measured. Results showed that sintering distortion in 4-unit monolithic zirconia FPDs occurred in all SC and SCL areas. Additionally, the sintering distortions were affected by the layered structure of the zirconia disks, the degree of which depended on the milling area (area I > area II > area III). Thus, when fabricating dental prosthesis using SCL zirconia disks, the milling area must be selected considering both the color adjustment and sintering distortion.

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, BV_2mm, BV_4mm, and BV_6mm, 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 6yBV_0mm.

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 6yBV_0mm were analyzed, 0yBV_0mm and 0yBV_2mm showed strong correlations with 6yBV_0mm (|r|≥.7). In the regression analysis, a 0yBV_0mm of 0.58 mm and 0yBV_2mm of 0.78 mm could be critical factors associated with a 6yBV_0mm of 0 mm. A 6yBV_0mm of 0yBV_0mm more than 0.58 mm was significantly higher than a 6yBV_0mm of 0yBV_0mm less than 0.58 mm (P<.001). Moreover, a 6yBV_0mm of 0yBV_2mm more than 0.78 mm was significantly higher than a 6yBV_0mm of 0yBV_2mm 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.

Patient with Poor Esthetic Anterior Tooth Position Treated with Lithium Disilicate Mesial Cantilever Single-retainer Fixed Partial Denture: A Case Report

We report a case of fixed prosthetic treatment for poor esthetics due to the position of the maxillary left lateral incisor in a 43-year-old woman. Initial examination revealed no carious lesions, but the tooth axis of the maxillary right canine showed mesial inclination of approximately 15°. Orthodontic treatment was first proposed but was declined by the patient as they did not wish to undergo a prolonged period of therapy. Therefore, recovery by extraction of the maxillary right lateral incisor and prosthetic treatment was proposed as an alternative. The method to be used for application of a 3-unit fixed partial denture and implant treatment was explained to the patient. She refused to give consent to this plan as well, however, due to concerns regarding the need to cut a lot from a non-problematic tooth and the length of time such treatment would require. Therefore, the problem was finally treated by application of a cantilever single-retainer fixed partial denture while giving sufficient consideration to extraction and occlusal contact. Lithium disilicate was used for the material of the prothesis. At 1 year after completion of treatment, no problem was observed with either the prosthetic appliance or the abutment teeth.

Influence of Tooth Mold Materials in Composite Resin CAD/CAM Crown Destructive Test

A range of experimental designs have been used in destructive testing of composite resin CAD/CAM crowns. Various materials have been adopted for the abutment in such tests, including human or bovine dentin, stainless steel, PMMA, and composite resin, the selection of which is made in accordance with study objective or preference of the researcher. The purpose of this study was to determine how the material selected for the abutment material affected fracture load and maximum displacement. Destructive tests were conducted on composite resin crowns of the same design. Three types of material were used for the abutments together with 2 types of adhesive material. Images of each sample were acquired before destruction using a microfocus X-ray CT scanner to confirm the feasibility of a non-destructive test.The load required to fracture the composite CAD/CAM resin crowns depended on the abutment material used, with a decrease being observed in the order of composite resin, stainless steel, and PMMA. Maximum displacement decreased in the order of PMMA, composite resin, and stainless steel. Differences in the material used for setting (adhesive resin or polycarboxylate cement) showed no effect on fracture load. These results indicate that the load required to achieve destruction of resin CAD/CAM crowns varies according to the abutment material used.

Low-temperature degradation of high-strength Y-TZP (yttria-stabilized tetragonal zirconia polycrystal)

The objective of this study was to investigate the low temperature degradation characteristics of 2 types of high strength yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in order to evaluate its suitability for implant body, implant superstructure or abutment. Disk-shaped conventional Y-TZP (0.25 mass% alumina) subjected to hot isostatic press treatment (HIP-Y-TZP) and Y-TZP/4Al₂O₃ with additional alumina (4.0 mass%) were mirror-polished. Accelerated aging tests with 134°C for 5 h at 0.2 MPa and 180°C for 5 h at 1.0 MPa were performed using an autoclave. Biaxial flexural strength and crystal phases were evaluated. Strength decreased as the proportion of monoclinic phase increased after accelerated aging treatment for both types of high-strength Y-TZPs. Despite the low alumina content, HIP-Y-TZP showed higher static strength and strength after accelerated aging treatment compared to Y-TZP/4Al₂O₃. However, both types of Y-TZP had adequate strength to be used as dental restorations even after accelerated aging treatment, therefore, its clinical suitability was considered high.

Usefulness of chemoradiotherapy for inoperable gastric cancer

Introduction Radiotherapy is not commonly used for the treatment of gastric cancer in Japan, where surgery is the standard local treatment. We report the results of chemoradiotherapy in patients with advanced or recurrent gastric cancer which was deemed difficult to treat surgically. Methods Twenty-one patients with gastric cancer (including sixteen with advanced/recurrent gastric cancer and five with poor general condition) underwent chemo-radiotherapy, for whom the therapeutic efficacy, toxicity and survival period were analysed. Results The tumour response to chemoradiotherapy was categorised as complete, partial, stable or progressive in 5, 9, 3, and 4 patients, respectively, with an overall response rate of 67%. No serious complications such as gastrointestinal perforation or bleeding occurred, and no cardiac, hepatic or renal dysfunction developed during the follow-up period. The mean survival time was 19.8 months (range, 3-51 months). One patient died of another disease, 18 died of primary cancer and the cause of death was unknown in 2 patients. Conclusions Chemoradiotherapy appears to be an effective treatment for localised gastric cancer without distant metastases, but further studies are needed to determine the indications for chemoradiotherapy and late adverse effects, as well as the chemotherapy regimens to be used.

Harvesting epithelial keratinocyte sheets from temperature-responsive dishes preserves basement membrane proteins and improves cell survival in a skin defect model

Cultured epithelial autograft (CEA) therapy has been used in clinical applications since the 1980s. However, there are some issues related to this treatment that still remain unsolved. Enzymatic treatment is typically used in the collection of epithelial keratinocyte sheets, but it tends to break the adhesion and basement membrane proteins. It is thought that the loss of proteins after enzymatic treatment is responsible for the poor survival of transplanted cell sheets. Our laboratory has developed a temperature-responsive culture dish that does not require enzymatic treatment to harvest the cells. In this study, we compare morphological and survival results from rat epithelial keratinocyte cell sheets harvested by temperature-reducing treatment (TT sheets) against cell sheets harvested by enzymatic (dispase) treatment (DT sheets). TT sheets preserve keratin structure in better conditions and express higher levels of collagen IV and laminin 5 than DT sheets. In order to evaluate cell sheet survival after transplantation, we created an in vivo transplant model. Keratinocyte sheets obtained from GFP-positive animals were transplanted into athymic rats. The survival rate 7 days after transplantation of TT sheet was higher than that of DT sheets. Collagen IV and Laminin 5 expression was observed in the TT sheet transplantation group. These results indicate that the remaining basement membrane proteins are important for initial attachment and cell survival. We believe that the cell sheet harvesting method using temperature-responsive culture dishes provides superior cell survival and can solve one of the roadblocks in CEA therapy. Copyright © 2016 John Wiley & Sons, Ltd.

A randomized, 12-month controlled trial to evaluate non-inferiority of early compared to conventional loading of modSLA implants in single tooth gaps

Background

The aim of the study was to evaluate whether early loading of implants with a chemically modified sandblasted, large-grit, acid-etched (SLA) (SLActive®) surface was non-inferior to conventional loading in terms of change in crestal bone level.

Methods

This was a randomized, controlled, multicenter study. Patients requiring single-tooth rehabilitation in the posterior maxilla or mandible received implants and were randomized to receive a provisional restoration in occlusal load after 25 ± 3 days (early loading) or after 13 ± 1 weeks (conventional loading). The primary endpoint was change in crestal bone level between implant placement (baseline) and 6 months. Secondary endpoints included change in crestal bone level between baseline and 12 months, implant survival and success rates, and patient satisfaction.

Results

Of the 84 patients enrolled, 78 received implants and were randomized onto the early loading (41 patients) and conventional loading (37 patients) groups. The mean change in crestal bone level between baseline and 6 months was 0.56 ± 0.58 and 0.51 ± 0.62 mm for early and conventional loading, respectively; at 12 months, the mean change was 0.76 ± 0.60 and 0.73 ± 0.77 mm, respectively. Implant survival and success at 12 months were 100 % for both groups. Patient satisfaction was similar between the groups, except that more patients in the early loading group were satisfied or highly satisfied with the time taken for fitting.

Conclusion

The study demonstrated that early implant loading was non-inferior to conventional implant loading in terms of crestal bone level change in a Japanese patient population in short follow-up period and single tooth gaps in molar regions.

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.

Influence of titanium ions on cytokine levels of murine splenocytes stimulated with periodontopathic bacterial lipopolysaccharide

PURPOSE

Titanium (Ti) is frequently used in dental implants because of its excellent corrosion resistance, mechanical properties, and biocompatibility. However, Ti ions may be slowly released as a result of corrosion, contributing to peri-implantitis, a major cause of dental implant failure. This study examined the influence of Ti ions on cytokine levels in murine splenocytes, an immunocompetent cell type, stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide (LPS) and the influence of Ti ions on splenocyte viability.

MATERIALS AND METHODS

Splenocytes were prepared from 5- to 10-week-old male C57BL/6 mice and BALB/c mice. Cytokine levels in culture supernatants from murine splenocytes stimulated with A actinomycetemcomitans LPS were determined with enzyme-linked immunosorbent assay. A tetrazolium salt assay was carried out to evaluate the cytotoxicity of Ti ions against murine splenocytes.

RESULTS

The present study demonstrated that Ti ions influence cytokine levels in LPS-stimulated splenocytes. Significantly higher values (P < .05) were observed for interleukins 1β, 6, and 10; interferon-γ; tumor necrosis factor alpha; and granulocyte macrophage colony-stimulating factor in the culture supernatants of LPS-stimulated splenocytes of both mouse strains in the presence of Ti ions, as compared to the absence of Ti ions. Tetrazolium salt assay confirmed that the Ti ions used in this study did not affect the viability of murine splenocytes.

CONCLUSION

This study suggests that Ti ions enhanced cytokine production induced by periodontopathic bacterial LPS.

Wear behavior between zirconia and titanium as an antagonist on fixed dental prostheses

The aim of this in vitro study was to investigate the wear behavior of the abrader when tetragonal zirconia polycrystal (TZP), cp-titanium (CpTi) and Ti-6Al-4V alloy (TiAlV) were used as the antagonist on fixed dental prostheses (FDPs). Both hemisphere abrader and flat substrate specimens were prepared using TZP, CpTi and TiAlV. Two-body wear tests were performed in distilled water, and the wear volume of the abrader specimen was measured to evaluate the wear behavior. In addition, scanning microscopic observation and an electron probe micro-analysis were performed to elucidate the underlying mechanism of the wear. The wear volume of CpTi and TiAlV abrader specimens was approximately 20 times larger than that of TZP abrader specimen against all substrate specimens. This is due to the differences in hardness between the ultra-hardness of TZP and the comparatively low hardness of CpTi and TiAlV. The wear volume of CpTi and TiAlV abrader specimens against the TZP substrate was significantly smaller than for the CpTi and TiAlV substrates despite the hardness of TZP being much larger than those of CpTi and TiAlV. This phenomenon may be based on the adhesive wear mechanism. Elements of Ti, Al and V originating in the TiAlV substrate were detected adhering to the abrader CpTi specimen. These results suggest that FDPs of CpTi and TiAlV are susceptible to wear against not only TZP but also CpTi and TiAlV in contrast to TZP FDPs.

Dental implant treatment after improvement of oral environment by orthodontic therapy

A 57-year-old man presented with mesial inclination of the lower right first molar caused by untreated loss of the second premolar. The occlusal relationship was restored by dental implant treatment following improvement of the intraoral environment by orthodontic therapy. At his initial visit, the interdental spacing in the molar-premolar region was inadequate, as the first molar had mesially inclined into the extraction space of the second premolar. The patient had also lost the second molar and complained of masticatory problems on the right side. It was considered necessary to restore the second molar and improve the occlusal relationship with the first molar to recover occlusal function on the right side. After orthodontic therapy to correct the position of the mesially inclined tooth, occlusal restoration was carried out by dental implant treatment. The patient's clinical condition has remained excellent at over 5 years 2 months post-surgically and the patient is satisfied with the treatment outcome. The combination of dental implant treatment and orthodontic therapy were effective in improving the intraoral environment in this patient, indicating the efficacy of interdisciplinary treatment planning and practice.

Intravenous sedation and hemodynamic changes during dental implant surgery

PURPOSE

The purpose of the present study was to determine whether intravenous sedation during dental implant surgery contributed to stabilization of hemodynamics.

MATERIALS AND METHODS

Two hundred fifty-five consecutive patients treated with dental implants were randomly assigned to receive either intravenous sedation with local anesthesia (sedation group, n = 123) or local anesthesia only (nonsedation group, n = 132). Midazolam and propofol were used synergistically as sedative agents. Systolic blood pressure, diastolic blood pressure, and pulse rate were measured every 2.5 minutes during dental implant surgery. On the basis of these data, the coefficient of variation, percentage of change, maximum values, and incidences of a larger increase were analyzed and expressed as cardiovascular changes.

RESULTS

A comparison of percentages of change, maximum values, and incidences of a greater increase showed that systolic and/or diastolic blood pressure were significantly higher in the nonsedation group than in the sedation group. The combination of midazolam and propofol sedation prevented excessive increases in blood pressure. The circulatory suppression induced by the intravenous sedation regimen not only reduced mental stress arising from the state of sedation but also exerted a pharmacologic effect. The application of this intravenous sedation regimen stabilized hemodynamics and contributed to the safety of the patient in dental implant surgery.

CONCLUSION

The application of intravenous sedation had a beneficial effect for hemodynamic changes during dental implant surgery.

Immediate implant placement in the maxillary central incisor region: a case report

PATIENT

A 67-year-old female with root fracture of the maxillary central incisor underwent implant placement immediately after extraction, with the goal of shortening the treatment period. The superstructure was placed on the implant after a 4-month healing period. Review 5 years after implant loading revealed no clinical problems.

DISCUSSION AND CONCLUSION

The treatment time was shortened effectively by the flapless immediate post-extraction placement procedure. Immediate post-extraction implant placement based on proper examination and diagnosis would reduce the patient burden.

Dental implant treatment with different techniques for sinus floor elevation--a case report

A 60-year-old man with missing maxillary molar teeth received dental implant therapy for reconstruction of occlusion. Sinus floor elevation with autogenous bone graft consisting of iliac bone block and particulate cancellous bone and marrow (PCBM) was performed in the bilateral maxillary sinuses for implant placement. On the right side, bone height in the molar region was less than 2mm. Therefore, a delayed protocol was applied, and 2 implants were placed 4 months after bone grafting. Bone graft resorption occurred during the healing period of 4 months. On the left side, 3 implants were placed simultaneously with sinus floor elevation, as bone height in the molar region was more than 4-5mm. The bone graft was carried out at the same time as implant placement. After implant placement, resorption of the bone graft stopped, and the superstructures were delivered on both sides. The tissues around the implants were clinically healthy at one year after examination. Sinus floor elevation with autogenous bone graft is an acceptable option for implant treatment in the maxillary molar region where there is adequate height of existing bone. In postoperative care, it is important to undertake adequate follow-up to ascertain occurrence of bone graft resorption.

The polymorphism interleukin 8 -251 A/T influences the susceptibility of Helicobacter pylori related gastric diseases in the Japanese population

BACKGROUND

Helicobacter pylori infection is associated with variable clinical outcomes, including gastroduodenal diseases, and genetic factors may be relevant in this process.

AIMS

We investigated the effects of an interleukin 8 (IL-8) gene polymorphism on the risk of gastroduodenal diseases, the degree of H pylori induced gastritis, and IL-8 gene transcription.

SUBJECTS

The study was performed in 244 healthy control subjects and 690 H pylori positive patients with non-cardia gastric cancer, gastric ulcer, duodenal ulcer, or gastritis.

METHODS

We identified the IL-8 -251 A/T polymorphism by direct sequence analysis, and measured the gastritis score and serum pepsinogen (PG). The transcriptional promoter activity of the IL-8 gene was assessed by luciferase assay.

RESULTS

IL-8 -251A was associated with a higher risk of gastric cancer and gastric ulcer. Patients carrying IL-8 -251A showed an increased risk of gastric cancer (odds ratios (OR) 2.01 (95% confidence interval (CI) 1.38-2.92)) and gastric ulcer (OR 2.07 (95% CI 1.37-3.12)). Compared with patients younger than 49 years, atrophy and metaplasia scores in the antrum were significantly higher and the PG I/II ratio significantly lower in -251A carriers than in T/T carriers. In the in vitro assay, IL-8 -251A showed enhanced promoter activity in response to IL-1beta or tumour necrosis factor alpha.

CONCLUSIONS

The IL-8 -251A allele may be associated with progression of gastric atrophy in patients with H pylori infection, and may increase the risk of gastric cancer and gastric ulcer in Japanese people.

Gastric acid secretion of normal Japanese subjects in relation to Helicobacter pylori infection, aging, and gender

BACKGROUND

In Japan, where the incidence of gastric cancer is high, Helicobacter pylori infection could affect gastric acid secretion differently from that in Western countries. The aim of this study was to investigate the relationship between H. pylori infection, acid secretion, aging, and gender in normal Japanese subjects.

METHODS

The study comprised 193 Japanese subjects who had undergone routine endoscopy. Gastrin-stimulated acid output was performed during the routine endoscopic examination using the endoscopic method of gastric acid secretory testing (EGT: endoscopic gastrin test), which has been reported previously. H. pylori status was determined by histology, rapid urease test, and serology.

RESULTS

Mean EGT values were 3.9 +/- 1.5 mEq/10 min in H. pylori-negative men, 1.6 +/- 2.5 in H. pylori-positive men, 2.2 +/- 0.9 in H. pylori-negative women, and 1.5 +/- 1.2 in H. pylori-positive women. Although acid secretion was lower in H. pylori-positive subjects compared with H. pylori-negative subjects in both men and women, the decrease was more marked in men with H. pylori infection. Multiple linear regression analysis showed that aging is positively associated with gastric acid secretion in the H. pylori-negative subjects, whereas a negative association was found between them in the H. pylori-positive subjects.

CONCLUSIONS

In Japanese subjects, aging affects gastric acid secretion differently depending on the status of H. pylori infection. H. pylori infection showed a stronger inhibitory effect on the acid secretion in men than in women. This gender-related difference in the susceptibility of acid secretion to H. pylori infection may explain the higher rates of gastric cancer in men in Japan.

Long-term effect of Helicobacter pylori eradication on the reversibility of acid secretion in profound hypochlorhydria

BACKGROUND

Although profound hypochlorhydria is considered to be an important risk factor for development of gastric cancer, long-term effect of Helicobacter pylori eradication on its reversibility remains uncertain.

AIM

To clarify the change in acid secretion after eradication in a long-term follow-up over 5 years in patients with profound hypochlorhydria.

METHODS

Twenty-three H. pylori-positive patients with hypochlorhydria (<0.6 mmol/10 min) were enrolled prospectively. Assessment of gastrin-stimulated acid output and histologic evaluation of biopsy specimens were performed prior to, and 1, 7 months after eradication. Subsequently, gastric acid secretion was assessed for long-term period over 5 years after eradication in 12 patients.

RESULTS

Gastric acid secretion was reversed to normal range in nine of 23 patients (39%) at 7 months after eradication. In the long-term follow-up, gradual and significant recovery in gastric acid secretion was observed up to 2 years post-therapy. However, there was no additional increase during the last 3 years of 5-year follow-up period, leaving the acid secretory levels subnormal in the majority of the patients.

CONCLUSIONS

This long-term follow-up study suggests that the pathologic process has already progressed to an irreversible stage in the majority of H. pylori-positive patients with marked body atrophy and profound hypochlorhydria.

Fluorescein angiography-guided indocyanine green angiography for the detection of feeder vessels in subfoveal choroidal neovascularization

AIMS

To compare the newly devised fluorescein angiography (FA) - guided indocyanine green angiography (ICGA) with conventional ICGA for detecting feeder vessels in subfoveal choroidal neovascularization (CNV).

METHODS

The detection of feeder vessels was attempted in 86 AMD patients with subfoveal CNV: 44 (age 70.4+/-4.5 years) underwent conventional ICGA (control group) and 42 (age 70.9+/-4.0 years) underwent an FA-guided ICGA (FA-guided group) using a double-detector scanning laser ophthalmoscope (SLO). In the control group, indocyanine green (ICG) was injected simultaneously with fluorescein. The patients were instructed to gaze forward localizing the fovea at the centre. In the FA-guided group, fluorescein sodium was injected a few minutes prior to ICG, and the patients were instructed to fixate in the appropriate direction by referring to the ongoing FA on the monitoring screen. In both groups, a 20 degrees visual angle was used to capture good images of feeder vessels in ICGA and, in case ICGA missed the first images of the entire CNV filling, an additional injection of ICG was given in the late phase to record the choroidal filling again. The overall detection rate, single-injection detection rate, double-injection rate and examination time were analysed using Fisher's direct exact probability test or Mann-Whitney's U-test.

RESULTS

There was no significant difference in the overall detection of feeder vessels between the two groups (50% in the control group and 52.3% in the FA-guided group; P=0.49 with Fisher's direct exact probability test). However, in the FA-guided group, the single injection detection rate was significantly higher (45.1 and 15.9%, respectively; P<0.001 with Fisher's direct exact probability test); significantly less double injections were required (7.1 and 50%, respectively; P=0.003 with Fisher's direct exact probability test); and significantly shorter examination times were needed (9.6+/-3.7 and 14.1+/-6.8 min, respectively; P=0.02 with Mann-Whitney's U-test).

CONCLUSION

FA-guided ICGA is effective for detecting feeder vessels of subfoveal CNV, minimizing the amount of ICG injected and the examination time compared to conventional ICGA.

Sensitivity of biopsy site in evaluating regression of gastric atrophy after Helicobacter pylori eradication treatment

BACKGROUND

Helicobacter pylori infection is a major cause of the progress of gastric glandular atrophy, a high-risk background factor in the development of gastric cancer. Regression of gastric atrophy is critical to prevention of cancer by H. pylori eradication treatment. However, it is controversial whether gastric atrophy regresses after H. pylori eradication.

AIM

To determine the most sensitive and appropriate biopsy site for evaluation of regression of atrophy after treatment.

SUBJECTS AND METHODS

Thirty-eight patients who showed regression of gastric atrophy in histology after treatment were investigated. Four biopsy specimens from the lesser and greater curvatures in the antrum and corpus were evaluated before and after treatment according to the Updated Sydney System.

RESULTS

Regression of atrophy after treatment was seen in 30 of 38 biopsy specimens from the lesser curvature of the corpus (79%), and this site was most sensitive. Odds ratio of this site to the others was 8.28. Regression of atrophy in this site was observed at 12.2 months in the younger patients and 15.9 months in the elder patients.

CONCLUSION

Biopsy sampling from the lesser curvature of the corpus is the most sensitive and appropriate for evaluation of regression of gastric atrophy after H. pylori eradication treatment.

17 beta-Hydroxysteroid dehydrogenase type 2 expression and enzyme activity in the human gastrointestinal tract

The 17 beta-hydroxysteroid dehydrogenases (17 beta HSDs) play an important role in the regulation of intracellular levels of biologically active sex steroid hormones in various human tissues. To date, eight distinctive 17 beta HSD enzymes have been cloned and characterized in humans. Among these isoenzymes, 17 beta HSD type 2 (17 beta HSD2) catalyses the conversion of testosterone into androstenedione and/or oestradiol into oestrone in various tissues, and it has thus been suggested to be involved in the biological inactivation of these sex steroids. The human gastrointestinal tract and liver are considered as the principle sites of inactivation and metabolism of various forms of orally administered sex steroids. We therefore examined 17 beta HSD2 expression and activity in human adult non-pathological gastrointestinal tract in order to clarify further the biological significance of this enzyme. A total of 80 specimens (40 from males and 40 from females) of normal oesophageal, stomach, duodenal, ileal, colonic and rectal tissues were examined for immunohistochemistry. Altogether, 17 tissue specimens were used for enzyme assay, and eight for RNA analysis. 17 beta HSD2 activity was detected in the stomach, duodenum, ileum, colon and rectum. 17 beta HSD2 mRNA was most abundant in the small intestine. 17 beta HSD2 immunoreactivity was localized almost exclusively to the absorptive epithelium, which may be involved in the inactivation of excessive endogenous and exogenous active sex steroids. Results from the present study thus suggest that the human gastrointestinal tract is an important sex steroid metabolizing organ in humans.

H+-ATPase defect in Corynebacterium glutamicum abolishes glutamic acid production with enhancement of glucose consumption rate

A mutant of Corynebacterim glutamicum ('Brevibacterium flayum') ATCC14067 with a reduced H+-ATPase activity, F172-8, was obtained as a spontaneous neomycin-resistant mutant. The ATPase activity of strain F172-8 was reduced to about 25% of that of the parental strain. Strain F172-8 was cultured in a glutamic-acid fermentation medium containing 100 g/l of glucose using ajar fermentor. It was found that glucose consumption per cell during the exponential phase was higher by 70% in the mutant than in the parent. The respiration rate per cell of the mutant also increased to twice as much as that of the parent. However, the growth rate of the mutant was lower than that of the parent. Under those conditions, the parent produced more than 40 g/l glutamic acid, while the mutant hardly produced any glutamic acid. Instead the mutant produced 24.6 g/l lactic acid as the main metabolite of glucose. Remarkably, the accumulation of pyruvate and pyruvate-family amino acids, i.e., alanine and valine, was detected in the mutant. On the other hand, the parent accumulated alpha-ketoglutaric acid and a glutamate-family amino acid, proline, as major by-products. It was concluded that the decrease in the H+-ATPase activity caused the above-mentioned metabolic changes in strain F172-8, because a revertant of strain F172-8, R2-1, with a H+-ATPase activity of 70% of that of strain ATCC14067, showed a fermentation profile similar to that of the parent. Sequence analyses of the atp operon genes of these strains identified one point mutation in the gamma subunit in strain F172-8.

An ancient lectin-dependent complement system in an ascidian: novel lectin isolated from the plasma of the solitary ascidian, Halocynthia roretzi

Mannose-binding lectin (MBL) is a C-type lectin involved in the first line of host defense against pathogens and it requires MBL-associated serine protease (MASP) for activation of the complement lectin pathway. To elucidate the origin and evolution of MBL, MBL-like lectin was isolated from the plasma of a urochordate, the solitary ascidian Halocynthia roretzi, using affinity chromatography on a yeast mannan-Sepharose. SDS-PAGE of the eluted proteins revealed a major band of approximately 36 kDa (p36). p36 cDNA was cloned from an ascidian hepatopancreas cDNA library. Sequence analysis revealed that the carboxy-terminal half of the ascidian lectin contains a carbohydrate recognition domain (CRD) that is homologous to C-type lectin, but it lacks a collagen-like domain that is present in mammalian MBLs. Purified p36 binds specifically to glucose but not to mannose or N-acetylglucosamine, and it was designated glucose-binding lectin (GBL). The two ascidian MASPs associated with GBL activate ascidian C3, which had been reported to act as an opsonin. The removal of GBL-MASPs complex from ascidian plasma using Ab against GBL inhibits C3-dependent phagocytosis. These observations strongly suggest that GBL acts as a recognition molecule and that the primitive complement system, consisting of the lectin-proteases complex and C3, played a major role in innate immunity before the evolution of an adaptive immune system in vertebrates.

Helicobacter pylori infection prevents erosive reflux oesophagitis by decreasing gastric acid secretion

BACKGROUND

Helicobacter pylori infection is less prevalent and atrophic gastritis is less extensive in patients with reflux oesophagitis than those without it, but few studies have examined this relationship directly.

AIMS

We investigated the relationship between H pylori infection, acid secretion, and reflux oesophagitis in Japanese subjects.

SUBJECTS

A total of 105 patients with erosive reflux oesophagitis were compared with 105 sex and age matched patients without reflux oesophagitis.

METHODS

The diagnosis of H pylori infection was made by histological examination of gastric mucosal biopsy specimens, rapid urease test, and detection of serum IgG antibodies. Acid secretion was assessed by the endoscopic gastrin test.

RESULTS

H pylori infection was present in 36 patients with erosive reflux oesophagitis (34.3%) and in 80 control subjects (76.2%) (odds ratio 0.163, 95% confidence interval 0.09-0.29). Overall acid secretion was significantly greater in patients with reflux oesophagitis. Among H pylori positive patients, acid secretion was greater in patients with reflux oesophagitis than those without oesophagitis.

CONCLUSION

In Japan, erosive reflux oesophagitis occurs most often in the absence of H pylori infection and gastric hyposecretion. Even in the presence of H pylori infection, reflux oesophagitis is more likely to develop in patients without gastric hyposecretion. H pylori infection may inhibit reflux oesophagitis by inducing hypoacidity.

Equivalent efficacy of mitomycin C plus doxorubicin instillation to bacillus Calmette-Guerin therapy for carcinoma in situ of the bladder

BACKGROUND

To elucidate the most efficient topical therapy for carcinoma in situ of the bladder, the efficacy of intravesical mitomycin C plus doxorubicin therapy was compared with bacillus Calmette-Guerin (BCG) therapy. The clinical behavior of the tumor was analysed according to the histological grade.

METHODS

Forty-two patients with carcinoma in situ of the bladder were randomized to intravesical BCG (21 patients) or mitomycin C plus doxorubicin sequential therapy (21 patients) as first line treatment. The non-responders underwent the subsequent instillation of the other intravesical therapy alternately. Of the patients, 27 had grade 2 and 15 had grade 3 cancer.

RESULTS

Both topical therapies were equally effective with initial response rates of 86% (18/21) for BCG and 81% (17/21) for mitomycin C plus doxorubicin, irrespective of the tumor grade. Of seven initial non-responders, five patients achieved a complete response by subsequent instillation, resulting in a total response rate of 95%. After a mean follow-up of 47 months, five patients (12%) developed disease progression. The progression rates were not different between the topical therapies, but were significantly higher in grade 3 than in grade 2 cases.

CONCLUSION

It appears likely that mitomycin C plus doxorubicin instillation has an equivalent efficacy to BCG as the initial therapy of carcinoma in situ and the combination of them would be the most efficient treatment for the disease. Moreover, histological grading would be clinically useful in defining the tumor characteristics and behavior of carcinoma in situ of the bladder.

Skin reactions after breast-conserving therapy and prediction of late complications using physiological functions

BACKGROUND

The temperature of the skin remains elevated long after breast-conserving treatment with irradiation, perhaps because evaporative cooling is impaired. We investigated physiological changes of the irradiated skin and reevaluated the radiosensitivity of sweat glands on a functional basis to determine whether severe complications can be predicted.

METHODS

Breast and axillary skin temperatures were measured with thermography and sweat production in response to local thermal stimuli was measured on the basis of changes in electrical skin resistance with a bridge circuit in 45 women before, during, and after breast irradiation for breast cancer.

RESULTS

Breast and axillary skin temperatures were significantly increased after irradiation. In response to cutaneous thermal stimuli, the electric skin resistance of nonirradiated areas decreased significantly because of sweating, but that of irradiated areas was unchanged.

CONCLUSION

Impairment of sweating may play an important role in skin damage after irradiation. Although glandular tissue is not usually radiosensitive, the results of our functional assessment suggest that sweat glands are more radiosensitive than expected.

Increased gastric acid secretion after Helicobacter pylori eradication may be a factor for developing reflux oesophagitis

BACKGROUND

The role of acid secretion in reflux oesophagitis which may develop after H. pylori eradication is not well known.

AIM

To investigate the participation of altered gastric acid secretion and the presence of hiatal hernia in the development of reflux oesophagitis after eradication therapy for H. pylori.

SUBJECTS AND METHODS

A total of 105 patients with H. pylori infection, but without reflux oesophagitis at the time of eradication therapy, were followed prospectively for 7 months after the clearance of this microorganism. Gastric acid secretion was assessed by endoscopic gastrin test, and the presence of hiatal hernia by endoscopy.

RESULTS

Reflux oesophagitis developed in 11 out of 105 (10.5%) patients when examined at 7 months after the eradication therapy. The incidence was correlated significantly with the increase in gastric acid secretion after the eradication of H. pylori, and was significantly higher in the patients with hiatal hernia (20%) than in those without it (0%).

CONCLUSIONS

Increased acid secretion after H. pylori eradication is an important risk factor of reflux oesophagitis, especially in patients with hiatal hernia.

Complement component C3 is not required for full expression of immune complex glomerulonephritis in MRL/lpr mice

Complement activation and tissue deposition of complement fragments occur during disease progression in lupus nephritis. Genetic deficiency of some complement components (e.g., Factor B) and infusion of complement inhibitors (e.g., Crry, anti-C5 Ab) protect against inflammatory renal disease. Paradoxically, genetic deficiencies of early components of the classical complement pathway (e.g., C1q, C4, and C2) are associated with an increased incidence of lupus in humans and lupus-like disease in murine knockout strains. Complement protein C3 is the converging point for activation of all three complement pathways and thus plays a critical role in biologic processes mediated by complement activation. To define the role of C3 in lupus nephritis, mice rendered C3 deficient by targeted deletion were backcrossed for eight generations to MRL/lpr mice, a mouse strain that spontaneously develops lupus-like disease. We derived homozygous knockout (C3(-/-)), heterozygous (C3(+/-)), and C3 wild-type (C3(+/+)) MRL/lpr mice. Serum levels of autoantibodies and circulating immune complexes were similar among the three groups. However, there was earlier and significantly greater albuminuria in the C3(-/-) mice compared with the other two groups. Glomerular IgG deposition was also significantly greater in the C3(-/-) mice than in the other two groups, although overall pathologic renal scores were similar. These results indicate that C3 and/or activation of C3 is not required for full expression of immune complex renal disease in MRL/lpr mice and may in fact play a beneficial role via clearance of immune complexes.

Immobilization of cycloisomaltooligosaccharide glucanotransferase for the production of cycloisomaltooligosaccharides from dextran

Immobilization of cycloisomaltooligosaccharide glucanotransferase (CITase) and its application in the production of cycloisomaltooligosaccharides (CIs) from dextran were studied. Among various carrier materials examined, the enzyme adsorbed physically on Chitopearl BCW-3505 showed the highest activity (1.75 U/ml carrier). The activity remaining was 35%. The maximum CI yield in batch reactions at 0.2, 2 and 10% dextran was 28, 24 and 12%, respectively. The maximum CI yield at 2% dextran (24%) was slightly less than that with the free enzyme under the same conditions (26%). The concentration of linear oligosaccharides, the byproducts in the reaction mixture, was greater with the immobilized CITase than the free enzyme. The immobilized CITase was less thermostable than the free enzyme by about 10 degrees C. The pattern of influence of Ca(2+) concentration on the thermostability differed between the free and immobilized CITase. A Ca(2+) concentration of 50-100 mM was optimum for the thermostability of the immobilized CITase, 10-50 mM for the free enzyme. CIs were produced continuously by a column system packed with the immobilized enzyme at 40 degrees C with a space velocity (SV) of 6 h(-1). The three quarters life time was 4 weeks. We think that relatively long life time at fast SV was accomplished and CI production cost by this method should be lower than the batch reaction. This is the first report on immobilization of CITase.

Solitary fibrous tumor of the prostate

An extremely rare case of solitary fibrous tumor of the prostate is presented. The patient underwent a radical retropubic prostatectomy and has remained well with no evidence of recurrence during the last 18 months. This is the fifth reported case of such a lesion arising in the prostate.

Brain metastasis as a sole recurrence of prostate cancer after total prostatectomy

Brain metastasis from prostate cancer is a rare clinical event. We present a case of prostate cancer with a solitary brain metastasis as a sole site of recurrence after total prostatectomy. To our knowledge, this is the third reported case of an isolated brain metastasis from prostate cancer.

The relationship between persistent secretion of RANTES and residual infiltration of eosinophils and memory T lymphocytes after Helicobacter pylori eradication

Helicobacter pylori (HP)-infected gastric mucosa displays a conspicuous infiltration of mononuclear cells as well as neutrophils. RANTES is a potent chemoattractant peptide for memory T lymphocytes and eosinophils. RANTES protein concentration and the numbers of RANTES-, CD45RO-, and major basic protein (MBP)-positive cells were therefore evaluated in the gastric mucosa from 51 patients with HP-positive chronic gastritis before and after HP eradication and from 22 HP-negative healthy volunteers. RANTES protein concentration was significantly elevated in HP-positive cases and remained high after HP eradication. The numbers of RANTES-, CD45RO-, and MBP-positive cells were significantly increased in HP-positive cases and were well correlated with RANTES protein levels. All tended to decrease after HP eradication, but did not reach the level of HP-negative cases, even at 24 months after HP eradication. It was concluded that persistent expression and secretion of RANTES were closely related to residual infiltration of memory T lymphocytes and eosinophils, for a prolonged period after HP eradication. This seems to be an important mechanism of prolonged gastric mucosal immune response against HP infection, even after HP eradication, and of persistent mucosal damage and atrophy.

Eosinophilic cystitis masquerading as invasive bladder cancer

We report the case of a 33-year-old woman with eosinophilic cystitis, which masqueraded as invasive bladder cancer. The patient remained well with no recurrence or progression after vigorous transurethral resection of the lesion.

Acute disseminated encephalomyelitis associated with poliomyelitis vaccine

A 6-year-old female patient with acute disseminated encephalomyelitis associated with poliomyelitis vaccine virus is reported. She had a history of high fever, headache, and gait disturbance. Neurologic examination confirmed spastic triparesis, urinary incontinence, diminution of tactile sensation, and vision deterioration. Hemography, serum laboratory findings, and urinalysis were normal. The cerebrospinal fluid was clear, with normal pressure, 9 leukocytes/mm(3), and 27 mg/dL protein, but the myelin basic protein was elevated to 10.7 ng/mL. T(2)-weighted magnetic resonance imaging disclosed multifocal high-intensity lesions of the spinal cord. The serum polio virus type 2 antibody titer was raised in the acute phase, and polio vaccine virus type 2 was detected in viral cultures of the cerebrospinal fluid and pharynx swab and had undergone an A-G neurovirulence mutation at nucleotide 481. Finally, she had human leukocyte antigen (HLA)-Cw3 and HLA-DR2, to which multiple sclerosis is related in Japan. Thus the cause of ADEM may have been related to her HLA type.