Effect of photofunctionalization on titanium bone-implant integration in ovariectomized rats.

Osteoporosis is considered a risk factor for osseointegration during implant treatment. Photofunctionalization of titanium has been shown to improve bone-based cell adhesion, proliferation, and functional expression, increasing the bone-implant contact rate and bone-implant integration strength. This study aimed to test the hypothesis that photofunctionalization is effective for implant fixation using an osteoporosis rat model. In the biomechanical push-in test, the bone-implant integration strength of the photofunctionalization treatment group was 1.53 times that of the control group (p<0.05). These values implied that photofunctionalization restored the ovariectomy-induced low bone-implant integration strength to normal states. In the micro-CT analysis, the BV/TV of the photofunctionalization treatment group was 1.32 times that of the control group (p<0.05). These values implied that photofunctionalization restored the ovariectomy-induced low peri-implant bone formation to normal states. These results indicate that photofunctionalization treatment increased peri-implant bone formation and bone-implant integration strength in ovariectomized rats.

Frictional Forces of Three Types of Lingual Appliance with Self-ligating Mechanisms.

AIM AND OBJECTIVE: The present study compared the frictional forces of three types of self-ligating lingual appliances. MATERIALS AND METHODS: The lingual appliances (2D, Forestadent; Alias, Ormco; and Clippy L, Tomy International) consisted of a self-ligating bracket (second premolar) and two self-ligating tubes (first and second molars) bonded to a stainless steel jig and attached to a "drawing-friction tester." Full-size and non-full-size stainless steel archwires were tested, and the static and kinetic friction acting on six lingual appliance/wire combinations was estimated (n = 5). Three-dimensional micro-computed tomography (micro-CT) analysis of each premolar bracket was performed. The frictional forces were compared between the bracket/wire combinations using the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The Alias and Clippy L bracket/wire combinations had greater contact between the wire surfaces and bracket slots compared to the 2D bracket/wire combination. For all lingual appliances, the static and kinetic frictional forces were significantly higher for the full-size than non-full-size archwire. The 2D bracket, which had a wider outer wing, had less frictional force than the other appliances. The Alias, which had a narrower outer wing, had a significantly lower frictional force than the Clippy L. CONCLUSIONS: Frictional force was significantly higher for heavier full-size bracket/archwire combinations than for non-full-size archwires. The 2D bracket had lower frictional force due to its archwire-holding mechanism. The outer wing width may influence the frictional resistance. CLINICAL SIGNIFICANCE: The frictional forces of self-ligating lingual appliances vary, and bracket design and archwire size may influence the frictional performance.

Esthetics of Orthodontic Appliances: Objective Evaluation by Spectrophotometry vs Subjective Evaluation Using the Visual Analog Scale Method.

AIM AND OBJECTIVE: In this study, we quantified the color of brackets and archwire appliances for an objective evaluation and investigated its relationship with subjective esthetic evaluation. MATERIALS AND METHODS: Five types of commercially available brackets (ceramic brackets C1, C2, and C3; plastic brackets P1 and P2) and three types of archwires (coated nickel-titanium archwires W1, W2, and W3) were used. The reflectance (%) and color (lightness: L*, hue: a*, b*) of each sample were quantified using a spectrophotometer (n = 5). Fifteen combinations of brackets and archwires were used. The esthetic evaluation was performed using the visual analog scale (VAS) method, and responses were obtained from 30 laypersons and 15 orthodontists. The mean VAS score was calculated, and the relationship between the reflectance and color of the bracket and archwire was discussed. RESULTS: The reflectance and L* of the brackets showed significantly higher values for C3 and C1 than for the others and lower values for P1 and P2. The reflectance and L* of the archwire showed significant differences among all samples. There was a high positive correlation between the reflectance and L*. There were statistically significant positive correlations between the layperson and orthodontist groups, between the VAS score and reflectivity, and between VAS score and L*. CONCLUSION: Our results showed that as the lightness and reflectance of the brackets and archwires increased, the subjective evaluation concerning their esthetic value was higher. CLINICAL SIGNIFICANCE: It is extremely difficult to evaluate esthetics despite the fact that patients' demands for esthetics have been increasing in recent years. If a method for evaluating esthetics is established, it should help in the development and selection of esthetic devices. The results of this study will facilitate the development of future study designs.

Degradation and Biocompatibility of AZ31 Magnesium Alloy Implants In Vitro and In Vivo: A Micro-Computed Tomography Study in Rats.

In current orthodontic practice, miniscrew implants (MSIs) for anchorage and bone fixation plates (BFPs) for surgical orthodontic treatment are commonly used. MSIs and BFPs that are made of bioabsorbable material would avoid the need for removal surgery. We investigated the mechanical, degradation and osseointegration properties and the bone-implant interface strength of the AZ31 bioabsorbable magnesium alloy to assess its suitability for MSIs and BFPs. The mechanical properties of a Ti alloy (TiA), AZ31 Mg alloy (MgA), pure Mg and poly-L-lactic acid (PLA) were investigated using a nanoindentation test. Also, pH changes in the solution and degradation rates were determined using immersion tests. Three-dimensional, high-resolution, micro-computed tomography (CT) of implants in the rat femur was performed. Biomechanical push-out testing was conducted to calculate the maximum shear strength of the bone-implant interface. Scanning electron microscopy (SEM), histological analysis and an evaluation of systemic inflammation were performed. MgA has mechanical properties similar to those of bone, and is suitable for implants. The degradation rate of MgA was significantly lower than that of Mg. MgA achieved a significantly higher bone-implant bond strength than TiA. Micro-CT revealed no significant differences in bone density or bone-implant contact between TiA and MgA. In conclusion, the AZ31 Mg alloy is suitable for both MSIs and BFPs.

The effects of single application of pastes containing ion-releasing particles on enamel demineralization.

We investigated single application of pastes containing a surface reaction-type pre-reacted glass-ionomer (S-PRG) filler on enamel demineralization. Human enamel blocks were polished using pastes containing S-PRG filler (0, 5, and 30%) and immersed in demineralizing solution for 5 days with daily change of solutions. The pH measurement and nanoindentation testing was carried out during the immersion period, and the enamel surfaces were examined using scanning electron microscopy and atomic force microscopy. A non-fluoride paste and a hydroxyapatite-containing paste were used for comparison. The specimens polished with the S-PRG filler-containing paste exhibited acid-neutralizing properties, which became stronger with an increasing S-PRG filler content. Following immersion in the demineralizing solution, specimens polished with the S-PRG filler-containing paste exhibited significantly greater hardness and elastic modulus values than those polished with the other pastes and exhibited a smoother surface than did the other specimens. Pastes containing S-PRG filler inhibits the demineralization of enamel.

Wear characteristics and inhibition of enamel demineralization by resin-based coating materials.

In this study, wear and inhibition of enamel demineralization by resin-based coating materials were investigated. Seven commercially available coating materials, with and without fillers, were used. A mechanical wear test was performed, and the specimens were then examined with a scanning electron microscope. Hardness and elastic modulus measurements for each material were obtained by nanoindentation testing. Thin layers of each material were applied on human enamel surfaces, which were subjected to alternating immersion in demineralizing and remineralizing solutions. The inhibition ability of enamel demineralization adjacent to the coating was estimated with depth-dependent mechanical properties using the nanoindentation test. The non-filled coating material showed significantly lower hardness, lower elastic modulus, and higher weight loss. There were no significant differences in weight loss among the six filled coating materials. After the alternating immersion protocol, the enamel specimens having application of coating materials with ion-releasing ability were harder than those in the other groups in some locations 1-11 µm from the enamel surface and within 300 µm from the edge of the coating materials. In conclusion, clinical use of the resin-based coating materials with ion-releasing ability may prevent demineralization of exposed enamel adjacent to the coating during treatment.

Low-dose aspirin-associated upper gastric and duodenal ulcers in Japanese patients with no previous history of peptic ulcers.

BACKGROUND: Long-term administration of low-dose aspirin (LDA) is associated with a greater risk of adverse events, including gastroduodenal ulcers. The purpose of this study was to identify the risk factors for and assess the role of medication use in the development of peptic ulcer disease in Japanese patients with no history of peptic ulcers. METHODS: Consecutive outpatients receiving LDA (75 mg/day) who underwent esophagogastroduodenoscopy between January and December 2010 were enrolled. Clinical parameters, peptic ulcer history, concomitant drugs, the presence of Helicobacter pylori infection, reason for endoscopy, and endoscopic findings were analysed. RESULTS: Of 226 total patients, 14 (6.2%) were endoscopically diagnosed with peptic ulcer. Age, sex, current smoking status, current alcohol consumption, endoscopic gastric mucosal atrophy, and abdominal symptoms were not significantly associated with peptic ulcers. Diabetes mellitus was more frequent (42.9% vs. 16.5%; P = 0.024) in patients with peptic ulcers than in those without peptic ulcers. Using multiple logistic regression analysis, co-treatment with anticoagulants or proton pump inhibitors (PPIs) was significantly associated with increased and decreased risk for peptic ulcer, respectively (odds ratio [OR], 5.88; 95% confidence interval [CI], 1.19 - 28.99; P = 0.03 and OR, 0.13; 95% CI, 0.02 - 0.73; P = 0.02, respectively). Co-treatment with additional antiplatelet agents, H2-receptor antagonists, angiotensin II Type 1 receptor blockers, angiotensin-converting enzyme inhibitor, 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, or nonsteroidal anti-inflammatory drugs was not associated with peptic ulcer development. CONCLUSION: The use of PPIs reduces the risk of developing gastric or duodenal ulcers in Japanese patients taking LDA without pre-existing gastroduodenal ulcers. However, this risk is significantly increased in both patients ingesting anticoagulants and patients with diabetes. These results may help identify patients who require intensive prophylaxis against aspirin-induced peptic ulcers.

Gossypiboma mimicking gastrointestinal stromal tumor causing intestinal obstruction: a case report.

A 41-year-old woman was admitted to our hospital with abdominal pain that developed about 1 year after a Cesarean section. Pelvic computed tomography (CT) revealed diffuse dilation of the small intestine with fluid shadows and a pelvic tumor 55 mm in diameter. The density of the tumor, which was not enhanced by intravenous contrast medium, was diffuse and similar to that of muscular tissue, whereas the density of a capsule surrounding the mass was relatively high. T1- and T2-weighted pelvic magnetic resonance imaging (MRI) of the tumor revealed the same diffuse low-intensity signals as muscular tissue, and diffuse high-intensity signals, respectively. The CT and MRI findings were consistent with those of a gastrointestinal stromal tumor (GIST) causing ileus of the small intestine. As inserting an ileus tube did not improve her symptoms, the patient was scheduled for tumor resection. The operative findings revealed a hard, solid tumor adhering to the surrounding small intestine. The macroscopic findings revealed that the tumor consisted of layers of stratified gauze surrounded by a thick granulomatous wall. The gossypiboma was considered to have originated from gauze that had been left behind after the Cesarean section. If a patient has a history of surgery, the possibility of gossypiboma should be considered when CT or MRI findings indicate features of GIST.

Long-term survival and improved quality of life after chemoradiotherapy to treat esophageal small cell carcinoma: a report of two cases.

In case 1, endoscopy revealed a submucosal tumor with central ulceration in the esophagus of a 54- year-old man. A biopsy specimen revealed small cell carcinoma without metastasis and the stage of the cancer was stage I (T2N0M0). Two cycles of concurrent cisplatin, etoposide and radiotherapy resulted in an incomplete response/stable disease. The tumor recurred and had metastasized to the brain, lung, liver, lymph nodes of the mediastinum, abdomen and bones after six cycles. Two cycles of irinotecan and cisplatin then elicited a complete response in the primary esophageal lesion. However, progressive disease was identified in the metastatic bone tumors. Despite two further cycles of therapy, he died 447 days after the initial course. In case 2, a biopsy specimen of a tumor with central ulceration in the esophagus of a 77-year old man with swallowing difficulty indicated small cell carcinoma. The stage of the cancer was diagnosed as stage II (T3N0M0). Two cycles of irinotecan, cisplatin and concurrent radiotherapy elicited a complete response. However, the tumor metastasized to the brain and the liver 644 days after starting treatment. Two cycles of carboplastin plus irinotecan elicited a partial response in the metastatic tumors, but he died 988 days after starting chemotherapy.

Changes in 12-Year First-Line Eradication Rate of Helicobacter pylori Based on Triple Therapy with Proton Pump Inhibitor, Amoxicillin and Clarithromycin.

A triple therapy based on a proton pump inhibitor (PPI), amoxicillin (AMPC), and clarithromycin (CAM) is recommended as a first-line therapy for Helicobacter pylori (H. pylori) eradication and is widely used in Japan. However, a decline in eradication rate associated with an increase in prevalence of CAM resistance is viewed as a problem. We investigated CAM resistance and eradication rates over time retrospectively in 750 patients who had undergone the triple therapy as first-line eradication therapy at Nagoya City University Hospital from 1995 to 2008, divided into four terms (Term 1: 1997-2000, Term 2: 2001-2003, Term 3: 2004-2006, Term 4: 2007-2008). Primary resistance to CAM rose significantly over time from 8.7% to 23.5%, 26.7% and 34.5% while the eradication rate decreased significantly from 90.6% to 80.2%, 76.0% and 74.8%. Based on the PPI type, significant declines in eradication rates were observed with omeprazole or lansoprazole, but not with rabeprazole. A decrease in the H. pylori eradication rate after triple therapy using a PPI + AMPC + CAM has been acknowledged, and an increase in CAM resistance is considered to be a factor. From now on, a first-line eradication regimen that results in a higher eradication rate ought to be investigated.