Fluoride release from newly developed dental adhesives

This study compared fluoride release from three fluoride-releasing dental adhesives (Trial KBF Bond, One-up Bond F, Reactmer Bond) and one conventional dental adhesive (Clearfil SE Bond) for 70 days in vitro. From each material, five disk-shaped specimens (diameter: 9.0 mm, height: 1.5 mm) were prepared and immersed in 5 ml of 10 mM phosphate buffered solution (pH 7.0). After 1, 3, 7, 14, 21, 28, 35, 42, 49, 56, 63 and 70 days, the samples were transferred into new solutions. The fluoride content was determined with a combined fluoride sensitive electrode attached to an ion analyzer. Data were statistically analyzed with ANOVA, followed by Scheffé's test. Reactmer Bond showed the greatest fluoride release over 70 days (280.2 +/- 10.1 micrograms/cm2) among the materials tested. The values for One-up Bond F and Trial KBF Bond were 83.4 +/- 5.3 micrograms/cm2 and 58.6 +/- 1.5 micrograms/cm2, respectively. The values were significantly different among the four groups (p < 0.0001). Clearfil SE Bond showed almost no fluoride release over 70 days.     

Gingival tissue-produced inhibition of platelet aggregation and the loss of inhibition in streptozotocin-induced diabetic rats

Addition of medium incubated with normal rat gingival tissue to platelet-rich plasma inhibited ADP-induced platelet aggregation. The ability of rat gingiva to produce activity inhibiting platelet aggregation was enhanced by the addition of arachidonic acid. Diabetic rat gingiva failed to inhibit platelet aggregation but did produce the anti-platelet aggregating activity in the presence of arachidonic acid. Indomethacin blocked the production of anti-platelet aggregating activity. There was no difference in conversion of [1-¹⁴C]arachidonic acid to prostaglandins by normal and diabetic rat gingiva. These results suggest that an arachidonic acid metabolite released from gingiva during incubation inhibits platelet aggregation, and the synthesis of the metabolite is impaired in diabetic rat gingiva. A decrease in availability of arachidonic acid may be a causal factor of the defect in diabetic rat gingiva.     

Development of a multi-layered virtual tooth model for the haptic dental training system

A virtual reality (VR) haptic dental training system could be a promising tool for future dental education. One major challenge is to develop a virtual tooth model which similarly reflected a real tooth having multiple layers with different mechanical hardness in each layer. The multi-layered virtual tooth model was successfully constructed in our virtual system. The constructed model allows us to feel tooth cutting which is similar to that with a real tooth. Through a cutting experiment by using the real tooth, a spring coefficient and a damping coefficient of a dental hard tissue were determined 0.8 N/mm and 1.79 Nsec/mm respectively. The feedback force smoothly altered when crossing the border of regions having different mechanical hardnesses. The constructed model introduced in this study could be a promising tool for acquiring dental hand skills in a virtual learning system.     

牙龈卟啉单胞菌对脐静脉血管内皮细胞产生sICAM-1的影响

目的：观察牙龈卟啉单胞菌（Porphyromonas gingivalis,P.gingivalis)对人类脐静脉血管内皮细胞（human umbilical vein endothelial cells,HUVECs)产生可溶性细胞间粘附分子－1（soluble intercellular adhesion molecule-1,sICAM-1)的影响。方法：应用厌氧袋法培养P.gingivalis，并用其感染HUVECs，采和酶联免疫吸附实验（enzyme-linked immunosorbent assay,ELISA)测定培养上清中sICAM-1的含量，结果：HUVECs基础表达少量的sICAM-1;P.gingivalis剂量依赖性增强HUVECs产生sICAM-1蛋白的水平；紫外线、超声波和65℃的热处理都不能抑制P.gingivalis的作用；sICAM-1蛋白水平在P.gingivalis刺激后的4h未见改变，增高的作用从刺激后的8h开始，在12h,16h和20h继续增加。结论：活的和灭活的P.gingivalis都剂量依赖性和时间依赖性地增强HUVECs产生sICAM-1,P.gingivalis可能同样诱导牙龈血管内皮细胞表达sICAM-1，升高的sICAM-1可能参与调节牙周病炎症反应和免疫反应过程。     

The effect of supragingival plaque control on the subgingival microbiota in subjects with periodontal disease

The present investigation was performed to study the effect on the subgingival microbiota, of a plaque control program which included meticulous oral hygiene instruction, supragingival scaling and professional monitoring during a 2 year period. 300 subjects were examined for periodontal disease and monitored for 2 years without treatment. After the 2 year examination, 80 subjects were invited to participate in a treatment program intended to improve the standard of their self-performed plaque control. 40 of the invitees had a gingivitis and only minor attachment loss, while 40 subjects had moderate signs of periodontitis. 62 subjects volunteered for this treatment. 23 of the volunteers (Group AB) had several sites with deep pockets (> 4 mm). 39 of the volunteers had gingivitis but shallow pockets only (Group C). Group AB contributed 31 shallow pocket sites (A-sites) and 40 deep pocket sites (B-sites), while Group C contributed 63 shallow sites (C-sites). After the clinical examination, samples of the subgingival microbiota were harvested from the 134 A, B and C sites. The 62 subjects were enrolled in a supervised oral hygiene program. Supragingival scaling was carried out. Oral hygiene instruction was provided and repeated on an individual need basis so that all subjects reached and maintained a supragingival plaque score which was < 20%. 24 months after the year 2 examination, the 62 subjects were examined again using both clinical and microbiological examination procedures. The findings demonstrated that carefully performed supragingival plaque control changed the quantity and the composition of the supragingival microbiota.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical site infection in spinal surgery: a comparative study between 2-octyl-cyanoacrylate and staples for wound closure

Background

Surgical site infection (SSI) after spinal surgery is a devastating complication. Various methods of skin closure are used in spinal surgery, but the optimal skin-closure method remains unclear. A recent report recommended against the use of metal staples for skin closure in orthopedic surgery. 2-Octyl-cyanoacrylate (Dermabond; Ethicon, NJ, USA) has been widely applied for wound closure in various surgeries. In this cohort study, we assessed the rate of SSI in spinal surgery using metal staples and 2-octyl-cyanoacrylate for wound closure.

Methods

This study enrolled 609 consecutive patients undergoing spinal surgery in our hospital. From April 2007 to March 2010 surgical wounds were closed with metal staples (group 1, n = 294). From April 2010 to February 2012 skin closure was performed using 2-octyl-cyanoacrylate (group 2, n = 315). We assessed the rate of SSI using these two different methods of wound closure. Prospective study of the time and cost evaluation of wound closure was performed between two groups.

Results

Patients in the 2-octyl-cyanoacrylate group had more risk factors for SSI than those in the metal-staple group. Nonetheless, eight patients in the metal-staple group compared with none in the 2-octyl-cyanoacrylate group acquired SSIs (p < 0.01). The closure of the wound in length of 10 cm with 2-octyl-cyanoacrylate could save 28 s and $13.5.

Conclusions

This study reveals that in spinal surgery, wound closure using 2-octyl-cyanoacrylate was associated with a lower rate of SSI than wound closure with staples. Moreover, the use of 2-octyl-cyanoacrylate has a more time saving effect and cost-effectiveness than the use of staples in wound closure of 10 cm in length.     

Gender differences in prognosis after esophagectomy for esophageal cancer

Purpose

The purpose of this study was to clarify the gender differences in the prognosis, as well as mortality and morbidity, of patients who have undergone esophagectomy for esophageal cancer.

Methods

The clinical results of esophagectomy were compared between 975 male and 156 female patients with esophageal cancer.

Results

The male to female ratios of cervical and thoracic esophageal cancer were 1.87 and 7.38, respectively (P < 0.01). The incidence of preoperative comorbidities was 32.4 and 17.4 %, respectively, and the rates of both tobacco and alcohol abuse were significantly lower in the females than in the males. The mortality rate was lower in the females (3.8 %) than in the males (5.7 %), although the differences were not significant. The overall survival was significantly better in the female than in the male patients (P = 0.039). The 5- and 10-year overall survival rates were 32.6 and 20.5 % in the males and 39.5 and 32.5 % in the females, respectively. A multivariate analysis revealed gender to be an independent prognostic factor. However, no significant differences were recognized in disease-specific survival.

Conclusions

These results suggest that the prognosis of females with esophageal cancer is better than that of males after esophagectomy, most likely due to multiple clinical factors, such as a more favorable lifestyle and general status.     

Randomized controlled trial of the LigaSure vessel sealing system versus conventional open gastrectomy for gastric cancer

Purpose

LigaSure, a bipolar electronic vessel sealing system, has become popular in abdominal surgery but few clinical studies have been conducted to evaluate its effectiveness in radical gastrectomy for gastric cancer.

Methods

In this multicenter, prospective, randomized controlled trial, patients with curative gastric cancer were randomly assigned to undergo gastrectomy either with LigaSure or a conventional technique.

Results

Of the 160 patients enrolled, 80 were randomized to the LigaSure group and 78 to the conventional group. Patient characteristics were well balanced in the two groups. There were no significant differences between the LigaSure and conventional groups in blood loss (288 vs. 260 ml, respectively; P = 0.748) or operative time (223 and 225 min, respectively; P = 0.368); nor in the incidence of surgical complications or duration of postoperative hospital stay. In a subgroup analysis of patients who underwent gastrectomy that preserved the distal part of the greater omentum, the use of LigaSure significantly reduced blood loss (179 vs. 245 ml; P = 0.033), and the duration of the operation (195 vs. 221 min; P = 0.039).

Conclusions

LigaSure did not contribute to reducing intraoperative blood loss, operative time, or other adverse surgical outcomes. The usefulness of the device may be limited to a specific part of the surgical procedure in open gastrectomy.     

Intraluminal exfoliated cancer cells and effectiveness of bowel ligatures during sigmoidectomy for sigmoid colon cancer

Purposes

To establish the efficiency of bowel ligatures in colon cancer surgery, focusing on the extent to which exfoliated cancer cells are shed in the colonic lumen during sigmoidectomy.

Methods

Twenty consecutive patients who underwent sigmoidectomy for sigmoid colon cancer were prospectively randomized into two groups: the “ligatures group”, in which bowel ligatures were placed, 3, 5, 10 cm from the tumor proximally and distally before dissection; and the “no ligatures group”, in which the corresponding sites were ligated only immediately before taking the specimen out. Each colonic segment ligated was irrigated with saline and samples were sent for blind cytological examination.

Results

Cancer cells were found in the colonic segment where the tumor was located, in 18 of 20 samples. The frequency of free cancer cells decreased from 50 to 0 % (p < 0.04) in the distal 3–5 cm colonic segment and from 80 to 20 % (p < 0.03) in the proximal colonic segment after performing bowel ligatures. Free cancer cells were confirmed in 1 of 10 samples at both colonic segments 5–10 cm from the tumor, even after bowel ligatures.

Conclusions

Intraluminal exfoliated cancer cells could be eliminated by placing bowel ligatures during sigmoidectomy. Measures should be considered to eliminate exfoliated cancer cells during colectomy, even after placing bowel ligatures.     

Risk factors for incisional surgical site infections in elective surgery for colorectal cancer: focus on intraoperative meticulous wound management

Purpose

An incisional surgical site infection (I-SSI) is a frequently observed complication following colorectal surgery. Intraoperative wound management is one of the most important factors that determine the incidence of postoperative I-SSI. The purpose of this study was to assess the impact of the methods used for intraoperative wound management on the incidence of I-SSI following elective surgery for colorectal cancer.

Methods

Between November 2009 and February 2011, the data of 1,980 consecutive patients who underwent elective colorectal resection for colorectal cancer were prospectively collected from 19 affiliated hospitals. The incidence of and risk factors for I-SSI were investigated.

Results

Overall, 233 I-SSIs were identified (11.7 %). Forty-two possible risk factors were analyzed. Using a multivariate analysis, the independent risk factors for I-SSI were identified to be a high body mass index, previous laparotomy, chronic liver disease, wound length, contaminated wound class, creation or closure of an ostomy, right hemicolectomy procedure, the suture material used for fascial closure and the incidence of organ/space SSI.

Conclusion

To prevent I-SSI following elective colorectal surgery, it is crucial to avoid making large incisions and reduce fecal contamination whenever possible. A high quality randomized control trial is necessary to confirm the definitive intraoperative procedure(s) that can minimize the incidence of I-SSI.