NRIP1 regulates cell proliferation in lung adenocarcinoma cells.

Nuclear receptor interacting protein 1 (NRIP1) is a transcription cofactor that regulates the activity of nuclear receptors and transcription factors. Functional expression of NRIP1 has been identified in multiple cancers. However, the expression and function of NRIP1 in lung adenocarcinoma have remained unclear. Thus, we aimed to clarify the NRIP1 expression and its functions in lung adenocarcinoma cells. NRIP1 and Ki-67 were immunostained in the tissue microarray section consisting of 64 lung adenocarcinoma cases, and the association of NRIP1 immunoreactivity with clinical phenotypes was examined. Survival analysis was performed in lung adenocarcinoma data from The Cancer Genome Atlas (TCGA). Human A549 lung adenocarcinoma cell line with an NRIP1-silencing technique was used in vitro study. Forty-three of 64 cases were immunostained with NRIP1. Ki-67-positive cases were more frequent in NRIP1-positive cases as opposed to NRIP1-negative cases. Higher NRIP1 mRNA expression was associated with poor prognosis in the TCGA lung adenocarcinoma data. NRIP1 was mainly located in the nucleus of A549 cells. NRIP1 silencing significantly reduced the number of living cells, suppressed cell proliferation, and induced apoptosis. These results suggest that NRIP1 participates in the progression and development of lung adenocarcinoma. Targeting NRIP1 may be a possible therapeutic strategy against lung adenocarcinoma.

Maintenance issues of elderly patients requiring nursing care with implant treatments in dental visiting: position paper.

PURPOSE: Japan, with an increasing number of elderly people needing long-term care in a super-aged society, urgent needs to develop the clinical guidelines on implant maintenance for elderly people with declining independence. The purpose is to categorize the troubles encountered in the care of patients with dental implants and to indicate actual practices and points of note. METHODS: From the members of the Japanese Society of Oral Implantology, 12 expert panelists who were experienced with many problems of implant maintenance during dental visits and were familiar with their solutions were selected. Through repeated discussions in the many panel meetings, the problems of implant maintenance during dental visits were distilled. RESULTS: During a dental visit, the oral cavity, general conditions, and background of elderly patients who cannot orally care for themselves must be grasped, and medical staff, care managers, and patients should understand the changes in these factors as time goes by. The solutions and responses that can be made differ greatly depending on the medical care facilities, the environment, differences in the experience of medical staff, and the patient's background. Thus, it is necessary to select safe treatments appropriate to each situation. CONCLUSIONS: This paper features many opinions based on clinical experiences. However, clinical guidelines on implant management during dental visits should be formulated in the future based on the accumulation of evidence through the implementation of clinical research.

(Pro)renin receptor and insulin signalling regulate cell proliferation in MCF-7 breast cancer cells.

(Pro)renin receptor [(P)RR] is related to both the renin-angiotensin system and V-ATPase with various functions including stimulation of cell proliferation. (P)RR is implicated in the pathophysiology of diabetes mellitus and cancer. Hyperinsulinemia is observed in obesity-related breast cancer. However, the relationship between (P)RR and insulin has not been clarified. We have therefore studied the effect of insulin on (P)RR expression, cell viability and AKT phosphorylation under the conditions with and without (P)RR knockdown. Effects of insulin were studied in a human breast cancer cell line, MCF-7. Cell proliferation assay was performed by WST-8 assay. (P)RR expression was suppressed by (P)RR-specific siRNAs. The treated cells were analysed by western blotting and reverse transcriptase-quantitative polymerase chain reaction analysis. Insulin stimulated proliferation of MCF-7 cells and increased (P)RR protein expression, but not (P)RR mRNA levels. Moreover, autophagy flux was suppressed by insulin. Suppression of (P)RR expression reduced cell number of MCF-7 cells and AKT phosphorylation significantly in both the presence and the absence of insulin, indicating that (P)RR is important for cell viability and AKT phosphorylation. In conclusion, insulin upregulates the level of (P)RR protein, which is important for cell viability, proliferation, AKT phosphorylation and autophagy in breast cancer cells.

Effect of firing temperature on the interface between 3Y-TZP zirconia and porcelain.

PURPOSE: The purpose of this study is to clarify the porcelain firing temperature conditions that give strongest bonding strength of porcelain to zirconia to manufacture all-ceramic fixed dental prostheses (FDPs) with excellent long-term stability. METHODS: Opaque porcelain samples (8.0 × 3.0 × 1.2 mm) were placed in the center of zirconia plates (25.0 × 3.0 × 0.5 mm) and fired at temperatures of 950°C, 1,050°C, 1,100°C, and 1,150°C. Schwickerath crack initiation tests, elemental analyses, and morphological changes of the samples were compared. RESULTS: There was no difference in the bonding strength among all the groups of porcelain fired at different temperatures. Elemental analysis of Si and O2 at the interface between the zirconia and porcelain were observed in the 950°C, 1,050°C, and 1,100°C groups. No silicon was found in the 1,150°C group by elemental analysis, and the zirconia plate where the porcelain sample was placed had irregular shape changes. CONCLUSION: It is suggested that silicon is also involved in chemical bonds due to firing at high temperatures.

Peri-implant tissue augmentation by volume-stable collagen matrix transplantation: a study of dog mandibles.

The aim of this study was to investigate histologically the amount of peri-implant tissue augmentation after volume-stable porcine collagen matrix transplantation. Six male beagle dogs were used in the experiment. P2, P4, and M1 distal roots were extracted under general anesthesia. After 6 months, implants were placed in the same sites, and volume-stable porcine collagen matrix transplantation was performed. Impressions were taken at 1 and 2 weeks and at 1, 2, and 3 months after transplantation. The dogs were euthanized at 3 months, and their mandibles were removed and scanned using micro-computed tomography. Standard Triangulated Language data were also obtained. Using preoperative models as a reference, the data for all time points were compared, and changes in the thickness of the cross-section of the implant sites were measured. The model created at 3 months was then compared with the mandible data, and the thickness of collected peri-implant soft tissue was measured under optical microscopy. Increased thickness was found at some of the sites on the buccal side. Regarding the peri-implant soft tissue, the thickness of the measured sites on the buccal side was significantly increased at 3 months in the experimental group. Histological observations of the internal structures of the tissue in the experimental group revealed irregular collagen fibers and a remnant collagen matrix. Endogenous tissue was observed within the collagen matrix, indicating good fusion with the surrounding autologous tissue. These results suggest that volume-stable porcine collagen matrix transplantation promotes peri-implant tissue augmentation on the buccal side.

Elevated (Pro)renin Receptor Expression by Anti-Cancer Drugs, Carboplatin and Paclitaxel, in Cultured Cancer Cells: Possible Involvement of Apoptosis and Autophagy.

(Pro)renin receptor [(P)RR] is a component of the renin-angiotensin system and plays an essential role in the activity of vacuolar H+-ATPase and autophagy. (P)RR is expressed in cancer cells. However, the relationship among (P)RR, apoptosis and autophagy in the treatment of anti-cancer drugs has not been clarified. The aim of this study was to clarify the effects of anti-cancer drugs with autophagy-promoting activity on (P)RR expression in cancer cells. MCF-7 breast cancer cells and A549 lung cancer cells were treated with carboplatin or paclitaxel, and the expression of (P)RR, apoptosis markers and autophagy markers were assessed by RT-qPCR, western blot analysis and immunocytochemistry. Expression levels of (P)RR mRNA and soluble (P)RR protein were increased by carboplatin or paclitaxel in a dose-dependent manner. Immunofluorescence staining of (P)RR was increased in both MCF-7 and A549 cells treated by carboplatin or paclitaxel. Apoptosis induction was shown by elevated BAX/BCL2 mRNA levels and increased active caspase3-positive cells. Moreover, autophagy induction was confirmed by increased levels of autophagy-associated mRNAs and LC3B-II proteins. (P)RR knockdown by (P)RR-specific siRNA suppressed the cell viability in MCF-7 cells and A549 cells under the treatment of carboplatin or paclitaxel, suggesting that (P)RR deficiency inhibits the proliferation of cancer cells in a pathway different from carboplatin or paclitaxel. The present study showed that the expression of (P)RR mRNA and soluble (P)RR was increased by anti-cancer drugs with autophagy-promoting activity. Upregulated (P)RR and autophagy may constitute a stress adaptation that protects cancer cells from apoptosis.

Effects of toothbrush abrasion on surface and antibacterial properties of hydroxyapatite-tryptophan complex with gray titania.

Photocatalysts have attracted attention in the medical field for their antibacterial effects. However, typical photocatalysts are activated by ultraviolet rays, which may have adverse effects. Therefore, we focused on a new photocatalyst that is activated by visible light, hydroxyapatite (HAp), and amino acid complex with gray titania, and evaluated its antibacterial effects against Porphyromonas gingivalis and effect by toothbrushing. The test sample was a titanium alloy substrate, and four surface treatments were applied: (1) substrate only, (2) substrate with HAp complex, (3) substrate with HAp complex with gray titania, and (4) HAp-tryptophan complex with gray titania (TR). These surface treatments were evaluated with or without toothbrushing (8 total groups). Surface roughness (Sa), fluorescent X-ray analysis (XRF), and scanning electron microscopy (SEM) were used to evaluate surface properties. To investigate antibacterial effects, each sample was seeded with P. gingivalis, irradiated with red light, and total viable bacterial count was determined. For Sa measurement, TR showed no significant difference after toothbrushing. However, in XRF and SEM observation, TR exhibited peeling of the applied coating after toothbrushing. In the antibacterial test, TR showed a decrease in P. gingivalis under no toothbrushing condition. Conversely, with toothbrushing, the TR coating appeared to peel. However, no significant difference in P. gingivalis count was observed among all groups. HAp-tryptophan complex with gray titania coating showed an antibacterial effect against P. gingivalis when irradiated with visible light. However, toothbrushing can result in coat peeling and consequently reduce the antibacterial effect.

Effects of porcelain veneering methods on conformity of the marginal and internal fit of three-unit zirconia framework.

The purpose of this study is to investigate the effects of porcelain veneering methods on the marginal and internal fit of a three-unit zirconia framework. A zirconia master model, in which the lower-left second premolar and the second left molar were used as the abutment, was obtained using an intraoral scanner. Based on the data, three-unit zirconia frameworks for fabricating all-ceramic bridges were designed and milled (FW group). Two types of all-ceramic bridge were fabricated by veneering porcelain onto these frameworks using the press-over technique (P group) and the layering technique (L group). The replica technique was used to measure the gap size between the abutments and the bridges. Measurements were taken in the marginal opening area (MO), chamfer area (CH), axial area (AX), and occlusal area (OC). Statistical analysis was performed using the Mann-Whitney U-test. There was no significant difference in MO and CH between the P and L groups. However, in AX, the L group had a significantly larger gap size than that of the P group (p = 0.003). In addition, compared with the FW group, the P group showed a significantly larger gap size in MO (p < 0.000), CH (p = 0.008), and OC (p < 0.000). These results indicate that the gap size increased after porcelain veneering using the press-over and layering techniques. In addition, the all-ceramic bridges fabricated using the press-over and layering techniques had approximately equal gap sizes in MO.

Effect of impression holding time and tray removal speed on the dimensional accuracy of impressions for artificial abutment tooth inclined.

Oral scanners allow dental impressions to be taken in a short time without the use of an impression material. However, it has been noted that high impression accuracy cannot be obtained in cases where the abutment is inclined or in cases where the span is long. Consequently, in daily clinical practice, impressions are often created using silicone impression material. When taking an impression using silicone impression material, the curing time or the removal time of the impression material are often based on the intuition of the dental staff. This study investigated the effects of impression holding time and impression tray removal speed on the dimensional accuracy of impressions. A specimen with an abutment inclined 30° to the removal direction of an impression was prepared. Four types of silicone rubber impression materials were used. Impressions were taken with two levels of holding time and two levels of removal speed using an autograph. The diameter of stone models was measured at 3, 6, and 9 mm from the baseline of each. The height of the inclined and opposite sides was also measured. Two-way analysis of variance was used to analyze data regarding the assessment of the effects of holding time and tray removal speed. The reproducibility of the impressions was affected by the volume of undercut caused by the inclined abutment. For a large undercut, longer holding times and faster tray removal speeds are recommended to reduce the deformation of silicone rubber impressions.

Marginal and internal fit of three-unit fixed dental prostheses fabricated from translucent multicolored zirconia: Framework versus complete contour design.

STATEMENT OF PROBLEM: Translucent multicolored zirconia materials enable more esthetic complete contour zirconia fixed dental prostheses (FDPs) than conventional zirconia, which exhibits low translucency and high opacity and is monochromatic. However, how the marginal and internal fit of translucent multicolored zirconia FDPs compare with those of traditional frameworks that require veneering is unclear. PURPOSE: The purpose of this in vitro study was to compare the marginal and internal fit of frameworks and complete contour 3-unit FDPs fabricated from translucent multicolored zirconia. MATERIAL AND METHODS: Frameworks with a thickness of 0.5 mm and complete contour FDPs with a thickness of 0.8 to 1.5 mm were manufactured by using a workflow similar to one from a zirconia master model (mandibular left second premolar-mandibular left second molar). Two polyvinyl siloxane replicas were made for each specimen to measure the marginal and internal fit. Measurement locations were mesial, lingual, buccal, and distal for each abutment. In these locations, the marginal opening (MO), chamfer area (CA), axial wall (AW), and occlusal area (OC) were measured. The data were analyzed with 2-way ANOVA and the Bonferroni post hoc test (α=.05). RESULTS: Frameworks showed significantly better mean ±standard deviation fit values than complete contour 3-unit FDPs at measurement areas MO (frameworks: 112 ±22 µm, complete contour FDPs: 144 ±37 µm) (P=.013), CA (frameworks: 89 ±12 µm, complete contour FDPs: 110 ±22 µm) (P=.006), and OC (frameworks: 182 ±36 µm, complete contour FDPs: 244 ±64 µm) (P=.008). At the measurement area AW (frameworks: 47 ±7 µm, complete contour FDPs: 50 ±9 µm of each location, no significant difference was observed between frameworks and complete contour FDPs (P=.361). CONCLUSIONS: Design differences in 3-unit FDPs fabricated from translucent multicolored zirconia influenced the marginal and internal fit. Frameworks had smaller marginal fit than complete contour FDPs for translucent multicolored zirconia.

Dental implant care and trouble among dependent patients based on the questionnaire survey among Japanese dental practitioners.

BACKGROUND: Self-care and professional care of implants may prove difficult for elderly people who require nursing care. However, the actual state of care and problems remains unknown. In this study, we investigated the actual state of implant problems in elderly people living in their own home or in a nursing home who received visiting dental treatment. METHODS: We mailed questionnaire survey forms to 2339 representatives or specialists who were members of the Japanese Society of Oral Implantology, the Japanese Society of Gerodontology or the Japan Prosthodontic Society. We narrowed down the respondents to those who provided visiting dental treatment, and analyzed the actual state of implants observed during visiting dental treatment (type, care, problems, countermeasures, etc.). RESULTS: Of the 924 dentists who responded to the questionnaire survey, 291 (22%) provided visiting dental treatment. While the majority of implant types encountered in the previous 12 months were root-form implants, there were still a certain number of blade and subperiosteal implants. Daily implant care involved mostly cleaning with a toothbrush + auxiliary tools. The most frequent implant problems encountered in the past were difficulty in cleaning and peri-implantitis. Medication and antiphlogistic treatment were most frequently adopted as countermeasures to implant problems, followed by observation. When we classified the results into those for the dentists who provided implant treatment and those for the dentists who did not, we found that many of the dentists who did not provide implant treatment opted for observation or medication, while those who provided implant treatment also implemented removal of superstructure, retightening of screws, repair and so forth. CONCLUSIONS: We found that many of the implant troubles encountered by dentists who provided visiting dental care were difficulty in cleaning or peri-implantitis, and that the actions taken against these troubles varied depending on the experience of the dentist performing the implant treatment. Our study also revealed that dentists who provide visiting dental care need to acquire knowledge and skills of implant treatment, to have actions prepared in case they encounter such cases, or to closely coordinate with dentists who specialize in implants.

Antibacterial activity of blue high-power light-emitting diode-activated flavin mononucleotide against Staphylococcus aureus biofilm on a sandblasted and etched surface.

BACKGROUND: Because of high affinity to the titanium implant surface, Staphylococcus aureus (S. aureus) has been reported as key microorganism that cause the peri-implantitis, even though it is not the typical periodontal pathogenic bacterial strain. The aim of this study was to evaluate the antibacterial property of the aPDT device, using blue high-power LED light activated flavin mononucleotide, comparing to the previously proven aPDT method using methylene blue and red laser on S. aureus biofilm. METHODS: Commercial pure titanium grade 4 modified surface with SLA were used to form S. aureus biofilm for 48 h. Two aPDT systems were used in this study; 1) HELBO®Blue Photosensitizer (Bredent medical), which is methylene blue (MB) activated by 670-nm red diode laser and 2) FotoSan® Blue agent Gel (CMS Dental), which contains flavin mononucleotide (FMN) activated by FotoSan® BLUE LAD (Light Activated Disinfection) light. The antibacterial tests were performed by total viable count, crystal violet assay, and direct observation methods. RESULTS: Using the light activated-PS, the log reduction in CFU/mL compared to non-treatment was 1.23 ±â€¯0.19 log10 and 1.23 ±â€¯0.12 log10 (about 93 % of reduction) for MB and FMN, respectively. The significant difference in the reduction could be determined when comparing with using only light (p < 0.01). Regarding two aPDT systems, the decrease in amount of bacteria after treatment was not significantly different (p > 0.05). CONCLUSION: The antibacterial activities of aPDT using blue high-power LED light activated flavin mononucleotide on S. aureus biofilm was comparable to those of previous research supporting aPDT using photoactivated MB.

Marginal and internal fit of three-unit zirconia fixed dental prostheses: Effects of prosthesis design, cement space, and zirconia type.

PURPOSE: The purpose of this study was to compare the marginal and internal fit of three-unit fixed dental prostheses (FDPs) fabricated using CAD/CAM with two designs, two cement space (CS), and two zirconia types. METHODS: A master model with two zirconia abutments and a missing tooth was scanned with an intraoral scanner. FDPs were fabricated with two designs (Full contour: FC, Framework: FW), two zirconia types (multi-layer: L, single-layer: W), and two CS values (30 and 45 µm for L and 30 µm for W). There were six experimental groups. The fit of the FDPs was evaluated using the replica method. The space between an abutment and the FDPs in the marginal (MO), chamfer (CH), axial (AX), and occlusal (OC) areas was measured under an optical microscope and the data was statistically analyzed using three-way ANOVA and Bonferroni test (p < 0.05). RESULTS: FW-l-45 µm showed a significantly smaller space than those for the FC in MO (p = 0.011), CH (p = 0.001) and AXE (p = 0.003). FW-l-30 µm showed a significantly smaller space than that for the 45 µm in AXE (p = 0.000) and OC (p = 0.016). FW-W-30 µm showed a significantly smaller space than that for the L in MO (p = 0.000), CH (p = 0.000), AXE (p = 0.000), and OC (p = 0.002). CONCLUSIONS: The design and CS of the FDPs affected the fit. FDPs with single-layer zirconia showed better fit than that obtained with multi-layer zirconia.

The Antibacterial Activity of Hydroxyapatite-Tryptophan Complex with Gray Titania by Photocatalysis Using LED Diodes.

PURPOSE: Peri-implantitis is an important biologic complication that can lead to implant failure. Proper treatment should effectively kill bacteria, not harm the implant surface, and promote regeneration. Recently, photocatalytic coating without antibiotics or external agents was proposed to be an alternative to antibiotic therapy. The aim of this study was to evaluate the photocatalytic antibacterial effect of a new titanium implant coating made from hydroxyapatite-tryptophan complex and gray titania, which was activated by two visible lights. MATERIALS AND METHODS: Titanium alloy substrate was plasma sprayed with hydroxyapatite (80 wt%) and dititanium trioxide (20 wt%) and then pressed with tryptophan. Three bacteria related to peri-implantitis, Porphyromonas gingivalis, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans, were used in this study. Six conditions were tested: (1) control group (only bacteria), (2) photocatalytic sample in darkness (bacteria and coated sample in darkness), (3) red laser for 15 minutes (bacteria irradiated with photoactivated disinfection [PAD] light, 650-nm wavelength), (4) broadband light-emitting diode (LED) for 15 minutes (bacteria irradiated with broadband LED, peak wavelength at 470 nm), (5) photocatalysis by red laser for 15 minutes (bacteria and coated sample irradiated with PAD light), and (6) photocatalysis by broadband LED for 15 minutes (bacteria and coated sample irradiated with broadband LED). After 15 minutes of irradiation, photocatalytic antibacterial effects were evaluated by total viable bacterial count, adenosine triphosphate (ATP) assay, and LIVE/DEAD assay. RESULTS: The number of all bacteria tested was significantly decreased by the photocatalytic effect of both visible light sources (P < .05). For P gingivalis, viable bacteria of lethal photosensitization groups were also significantly decreased (P < .05), especially when using the broadband LED. However, the coating material itself did not have antibacterial properties without light activation. There was no significant difference in ATP among groups (P > .05). LIVE/DEAD staining showed that red fluorescent bacterial cells were present in photocatalytic groups from the two light sources. CONCLUSION: Photoactivated hydroxyapatite-tryptophan complex and gray titania as a photocatalytic coating has antibacterial effects on bacteria associated with peri-implantitis.

Effects of heat conduction of implant surface at thermal stimulation on implant placement.

The purpose of this study is to investigate, in vitro, how two different implant placement methods (one and two-stage implant placement) affect implant surface temperature after thermal stimulation. Two titanium screw implants were used and three thermocouples were attached to the implant surface at 0.5 mm (ch1), 5.5 mm (ch2) and 9.0 mm (ch3) under each platform. Experimental devices were fabricated pouring polymerization resin under a condition that imitated the two embedded technique with the one-stage implant placement model (1-stage) and the two-stage implant placement model (2-stage). A hot water storage device was installed in each model and hot water at three temperatures (60 °C, 70 °C and 100 °C) was flowed. The temperature change over time at the implant surface by the thermocouple was recorded. From the measurement data, the maximum temperature (Max-temp) at the implant surface, the time to reach 47 °C (47 °C r-time), and the duration of 47 °C or more (47 °C c-time) were calculated, and the test was repeated 26 times using the same method. The mean of repeated measurements was determined and statistical analysis was performed. Max-temp showed significant differences between each implant placement method, each channel and each thermal stimulation (p < 0.01). In this study suggested that the implant surface could reach 47 °C with 60 °C thermal stimulation in a 1-stage. In addition, it rose over 47 °C at 70 °C. The 2-stage implant surface did not rise to 47 °C.

Cytotoxicity of hydroxyapatite-tyrosine complex with gray titania coating on titanium alloy surface to L929 mouse fibroblasts.

Hydroxyapatite particles (HAp) have been widely used by many dental implant systems as an implant coating material because of their osteoconductive properties. This study aimed at improving the antibacterial effect of HAp as a substitute for antibiotic agents which can increase drug resistance. HAp/gray titania was selected as the coating material for on the titanium alloy substrate due to its antibacterial properties after photocatalytic reaction. When combined with amino acids, HAp can form a fluorescent complex which enhances this property. Before clinical application, this new coating should be examined for cytotoxic effects against biological cells or tissues. Therefore, L929 mouse fibroblasts were used to represent fibrous tissue surrounding dental implant. After performing a 6-day alamarBlue assay, the new coating method using hydroxyapatite-tyrosine complex with gray titania on titanium alloy surface can be said to have no influence on the growth of fibroblasts.

Influence of the difference between implant body and screw materials on abutment screw loosening.

The purpose of this study was to investigate how differences in dental implant and screw materials affected screw loosening. Screws (pure titanium; Ti4S, titanium alloy; TiAS), blocks (Y-TZP; ZrB, pure titanium; Ti4B) and plates (Y-TZP; ZrP), representing abutment screws, implant bodies and superstructures, respectably, were used. Plates were fastened to blocks by screws using a torque of 20 N•cm, and the loosening torque was measured after cyclic loading. Tests was performed on 13 specimens per group, with four groups for loading at the eccentric point (9 mm from screw center) and one group at the centric point (3 mm from screw center). In eccentric point tests, Ti4S screws led to significantly more loosening than TiAS screws (p<0.01). The block material had no effect. For ZrBTi4S, there was no difference in loosening before and after the centric point tests. More loosening occurred for eccentric point than for centric point tests (p<0.05).

Hard and soft tissue responses to implant made of three different materials with microgrooved collar in a dog model.

The objective of the present study was to assess hard and soft tissue around dental implants made of three different materials with microgrooves on the collar surface. Microgrooved implants were inserted in the mandibles of five male beagles. Implants were made of three kinds of material; titanium (Ti), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria partially stabilized zirconia/alumina nanocomposite (Ce-TZP/Al2O3). The animals were euthanatized at three months after implantation, and harvested tissue was analyzed by means of histology. All kinds of implant were osseointegrated, and there were no significant differences in any histomorphometric parameters among the three groups of microgrooved implants made of different materials. Within the limitations of this study, implants with microgrooves integrated into the surrounding bone tissue, without statistically significant differences among the three tested materials, Ti, Y-TZP, and Ce-TZP/Al2O3.

A preliminary report on dental implant condition among dependent elderly based on the survey among Japanese dental practitioners.

BACKGROUND: The objective of this study was to ascertain the situation relevant to implants, the status of oral self-care, the status of aftercare provided by the dentist who placed the implant, and the usage status of the implant card, in homebound or institutionalized older adults who are receiving home-visit dental care due to the inability to visit a dental clinic on their own. METHODS: A survey questionnaire was sent by post mail to 2339 people who are representative members or dental specialists belonging to any of the following three academic societies: Japanese Society of Oral Implantology, Japanese Society of Gerodontology, and Japan Prosthodontic Society. The survey questions asked were about provision/no provision of implant treatment, provision/no provision of home-visit dental care, the situation of patients after implant treatment, the situation of implants in the context of home-visit dental care, and the usage status and recognition of the implant card. RESULTS: No less than 30% of the dentists had patients who were admitted to the hospital or became homebound after receiving implant treatment at their clinic. Twenty-two percent of the dentists had been consulted about the implants. Dentists who continued to provide post-operative implant care through home-visit dental care accounted for approximately 80%. On the other hand, however, 40% of the dentists did not know the post-implantation status of their implant patients. Of the patients receiving home-visit dental care, approximately 3% had implants (identified mainly by visual inspection). It was found that more than 50% of the dentists offering implant treatment did not use the implant card, and even in cases where it was used, most of the cards were not in the standardized format. CONCLUSIONS: Within the limitation of low response rate to the questionnaire in this preliminary study, we concluded that many of practitioners including specialists indicated the need of universal record of implant for dependent elderly cares.

Fracture force for veneered materials on restorations measured by torsion testing.

The torsional fracture strength at the interface between a base plate and veneering material was evaluated for three kinds of veneered restoration: porcelain fused to zirconia (PFZ), porcelain fused to metal (PFM), and composite resin veneered metal (CRVM). The metal and zirconia base plate (30×4×0.4 mm) were prepared and these plates were veneered as test specimens using each material to a total thickness of 1.2 mm. Torsional force was applied to each specimen using a rotational speed of 1.0 deg/min until the veneering material underwent fracture or exfoliation. The torsional fracture values were measured and the data were statistically analyzed using one-way ANOVA. The torsional fracture strength for PFZ, PFM, and CRVM was 3.0, 3.1, and 11.1 N•cm, respectively.