Impact of Direct Observation on Hand Hygiene Compliance in a Dental University Hospital: A Retrospective Cohort Study.

Introduction Hand hygiene is crucial for preventing healthcare-associated infections in dental settings. Despite its importance, the hand hygiene compliance rates remain unclear, particularly in dental university hospitals where teaching, research, and clinical practice intersect. This study aimed to establish a baseline of hand hygiene compliance rates in a dental university hospital, evaluate the effectiveness of direct observation in improving compliance, and compare practices among different categories of healthcare workers. Materials and methods This retrospective cohort study was conducted at Kanagawa Dental University Hospital from April 2022 to March 2023. The design included four blinded direct observations to establish baseline compliance rates, followed by educational training and four unannounced explicit observations. Compliance was assessed based on the World Health Organization's "Your 5 Moments for Hand Hygiene: Dental Care," adapted for dental outpatient services. The study focused on hand hygiene using alcohol-based hand sanitizers, and compliance rates were calculated for dentists, dental hygienists, dental assistants, and trainee dentists. Monthly consumption of hand sanitizer per patient was tracked from January 2019 as a secondary measure. Statistical analysis included Fisher's exact test, unpaired t-tests, and analysis of variance (ANOVA). Results The baseline hand hygiene compliance rate was low at 15.6%, with the highest compliance (25.0%) for "After touching patient surroundings." Post-intervention, the overall compliance rate increased significantly to 36.0% (p < 0.001). Significant improvements were observed in moments "After body fluid exposure risk" (11.1% to 31.3%, p = 0.004), "After touching a patient" (12.0% to 52.9%, p = 0.006), and "After touching patient surroundings" (25.0% to 73.3%, p = 0.001). Dental hygienists, assistants, and trainee dentists showed significant increases in hand hygiene compliance, while dentists did not. Hand sanitizer consumption increased significantly from 2019 (2.38 ± 0.29 mL per patient) to 2020 (3.47 ± 0.49 mL, p < 0.001) and remained elevated through 2023. Conclusions This study revealed low baseline hand hygiene compliance in a dental university hospital setting. While direct observation and education led to significant short-term improvements, especially among allied health professionals, the disconnect between observed compliance rates and hand sanitizer consumption suggests these changes may not represent sustainable behavioral shifts. The varying improvement rates among different healthcare workers and the challenges in maintaining long-term adherence highlight the need for tailored, continuous interventions in dental education and practice settings to enhance hand hygiene compliance.

The essential role of intestinal microbiota in cytomegalovirus reactivation.

Human cytomegalovirus (HCMV) is a member of Herpesviridae. It has been reported that HCMV is reactivated in the breast milk of HCMV-seropositive lactating women. As we have reported various aspects of the roles of indigenous microbiota, its role in the murine CMV (MCMV) reactivation was examined in this study. MCMV was latently infected in the salivary gland, mammary tissues, and colon in the pregnant mice. When the salivary gland, mammary tissues, and colon were removed 5 days after delivery, MCMV reactivation of latent infection in each organ was confirmed by the detection of MCMV IE1 mRNA using reverse transcription-quantitative PCR. MCMV reactivation was observed in 100% of the mice during pregnancy. Next, for the elimination of intestinal microbiota, the pregnant mice were treated with low-dose or high-dose non-absorbable antibiotics. Although the numbers of aerobe/anaerobe in cecal content in low-dose antibiotic-treated mice were comparable to those in untreated controls, high-dose antibiotic treatment decreased the number of aerobe/anaerobe microbes from ca.9.0 Log10 to ca.3.0 Log10 (cfu/g). However, it could not be confirmed in 16S rRNA analysis that specific bacterial phylum or genus was eliminated by this high-dose treatment. Interestingly, MCMV reactivation was also observed in 100% of low-dose antibiotic-treated mice, whereas, in high-dose antibiotic-treated mice, MCMV reactivation was not observed in the salivary gland or colon. MCMV IE1 mRNA was detected only in 33% of the mammary tissues of those high-dose-treated mice. These results suggest that the indigenous microbiota played a crucial role in the reactivation of latent infection. IMPORTANCE Human cytomegalovirus (HCMV) infection via breast milk is a serious problem for very preterm infants such as developing a sepsis-like syndrome, cholestasis, or bronchopulmonary dysplasia, among others. It has been reported that HCMV is reactivated in the breast milk of HCMV-seropositive lactating women. In this study, the roles of indigenous microbiota in the murine CMV (MCMV) reactivation were examined using a mouse model. In MCMV latently infected mice, MCMV reactivation was observed in 100% of the mice during pregnancy. For the elimination of intestinal microbiota, MCMV-latent mice were treated with non-absorbable antibiotics. After delivery, MCMV reactivation was not observed in antibiotic-treated mice. This result suggested that the indigenous microbiota played a crucial role in the reactivation of latent infection.

The stain resistant effect of an ultraviolet curable coating material on denture base resin.

This study aimed to evaluate the effects of an ultraviolet (UV) curable coating material on denture base resin. The results of the three-point bending test showed no significant difference between treated and untreated specimens, suggesting that the UV curable coating material did not compromise the physical strength of denture base resin. The surface free energy measurement and the surface analysis with atomic force microscopy revealed superhydrophilicity and a regularly arranged structure on the coating surface, improving wettability. Moreover, untreated specimens were significantly discolored in the staining test. However, specimens treated with the UV curable coating material showed no significant difference in color with slight staining, suggesting excellent antifouling ability. Therefore, the UV curable coating material used in this study could contribute to simplifying hygiene without altering the physical properties of denture base resins.

Detection of cross-reactive immunoglobulin A against the severe acute respiratory syndrome-coronavirus-2 spike 1 subunit in saliva.

Abundant secretory immunoglobulin A (SIgA) in the mucus, breast milk, and saliva provides immunity against infection of mucosal surfaces. Pre-pandemic breast milk samples containing SIgA have been reported to cross-react with SARS-CoV-2; however, it remains unknown whether SIgA showing the cross-reaction with SARS-CoV-2 exists in saliva. We aimed to clarify whether SIgA in saliva cross-reacts with SARS-CoV-2 spike 1 subunit in individuals who have not been infected with this virus. The study involved 137 (men, n = 101; women, n = 36; mean age, 38.7; age range, 24-65 years) dentists and doctors from Kanagawa Dental University Hospital. Saliva and blood samples were analyzed by polymerase chain reaction (PCR) and immunochromatography for IgG and IgM, respectively. We then identified patients with saliva samples that were confirmed to be PCR-negative and IgM-negative for SARS-CoV-2. The cross-reactivity of IgA-positive saliva samples with SARS-CoV-2 was determined by enzyme-linked immunosorbent assay using a biotin-labeled spike recombinant protein (S1-mFc) covering the receptor-binding domain of SARS-CoV-2. The proportion of SARS-CoV-2 cross-reactive IgA-positive individuals was 46.7%, which correlated negatively with age (r = -0.218, p = 0.01). The proportion of IgA-positive individuals aged ≥50 years was significantly lower than that of patients aged ≤49 years (p = 0.008). SIgA was purified from the saliva of patients, which could partially suppress the binding of SARS-CoV-2 spike protein to the angiotensin converting enzyme-2 receptor. This study demonstrates the presence of SARS-CoV-2 cross-reactive SIgA in the saliva of individuals who had never been infected with the virus, suggesting that SIgA may help prevent SARS-CoV-2 infection.

Oral administration of trehangelin-A alleviates metabolic disorders caused by a high-fat diet through improvement of lipid metabolism and restored beneficial microbiota.

The present study investigated whether or not the oral administration of trehangelin-A (THG-A) is effective for metabolic disorders caused by a high-fat diet, as we previously showed that the intraperitoneal administration of THG-A improved metabolic disorders caused by a high-fat diet. Mice received a control diet or high-fat diet for eight weeks. Concurrently, mice were orally administered 0.2 ml/mouse phosphate-buffered saline (PBS) or 1 or 10 mg/0.2 ml/mouse of THG-A once daily during the experiment. The weight gain caused by a high-fat diet was significantly suppressed by oral THG-A compared to a high-fat diet without THG-A. In addition, at eight weeks after starting the diet, the increased plasma total-cholesterol (T-CHO) and low-density lipoprotein-cholesterol (LDL-C) levels caused by a high-fat diet were significantly reduced by 10 mg/mouse THG-A and tended to attenuated by 1 mg/mouse THG-A. The LDL receptor and CYP7A1 mRNA expression in liver associated with lipid metabolism for reducing plasma LDL-C levels was significantly enhanced by oral THG-A. In contrast, oral THG-A exerted no marked effects on mice fed the control diet. The dysbiosis of a high-fat diet fed mice, which is in the form of an increased Firmicutes-to-Bacteroidetes ratio, also recovered, and the high-fat diet induced decreased levels of Bacteroides and Akkermansia genera, which are beneficial microbiota against metabolic disorders, were also restored by oral THG-A. These results indicate that oral THG-A administration acts on metabolic disorders by improving the lipid metabolism and restoring beneficial microbiota to resolve high-fat diet induced dysbiosis.

Efficacy and safety of PERIOdontal treatment versus usual care for Nonalcoholic liver disease: protocol of the PERION multicenter, two-arm, open-label, randomized trial.

BACKGROUND: We report the first protocol for a multicenter, randomized comparison study to compare the efficacies of periodontal scaling and root-planing treatment against that of tooth-brushing treatment for nonalcoholic fatty liver disease (NAFLD) (PERION: PERIOdontal treatment for NAFLD). Nonalcoholic steatohepatitis (NASH) is an advanced form of NAFLD, which can progress to cirrhosis and hepatocellular carcinoma. Increased endotoxemia is associated with the progression of NAFLD. Periodontal bacteria possess endotoxins; Porphyromonas gingivalis is well-known as a major pathogenic bacterium in periodontitis, and serum antibody levels for P. gingivalis are high in patients with periodontitis. Several reports have indicated that P. gingivalis is related to NAFLD. This study aims to investigate the effect of periodontal treatment for liver damage, P. gingivalis infection, and endotoxemia on patients with NAFLD. METHODS: We will include adult patients (20-85 years old) with NAFLD, alanine aminotransferase (ALT) ≥ 40 IU/L, and equivalent steatosis grade ≥ 1 (target sample size, n = 40 patients; planned number of patients with outcome data, n = 32). Participants will be randomly assigned to one of two groups: a scaling and root-planing group or tooth-brushing as the usual group. The primary outcome will be the change in ALT levels from baseline to 12 weeks; the key secondary outcome will be the change in the serum immunoglobulin G (IgG) antibody titer for P. gingivalis at 12 weeks. DISCUSSION: This study should determine whether periodontal treatment decreases liver damage, P. gingivalis infection, and endotoxemia in patients with NAFLD. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN) Clinical Trials Registry, ID: UMIN000022079.

NKT cells are responsible for the clearance of murine norovirus through the virus-specific secretory IgA pathway.

Norovirus infection cause epidemic nonbacterial gastroenteritis in patients. The immune mechanisms responsible for the clearance of virus are not completely understood. We examined whether NKT cells are effective against norovirus infection using CD1d KO mice. The body weights of 4-weeks-old CD1d KO mice that were infected with murine norovirus-S7 (MNV-S7) were significantly lower than those of non-infected CD1d KO mice. On the other hand, the body weights of infected WT mice were comparable to those of non-infected WT mice. Correspondingly, CD1d KO mice had an almost 1000-fold higher MNV-S7 burden in the intestine after infection in comparison to WT mice. The mechanism responsible for the insufficient MNV-S7 clearance in CD1d KO mice was attributed to reduced IFN-γ production early during MNV-S7 infection. In addition, the markedly impaired IL-4 production in CD1d KO mice resulted in an impaired MNV-S7-specific secretory IgA production after MNV-S7 infection which is associated with mucosal immunity. Thus, the present results provide evidence that NKT cells play an essential role in MNV-S7 clearance.

Improvement Effects of Trehangelin A on High-Fat Diet Causing Metabolic Clinical Conditions.

The purpose of this study is to determine whether or not trehangelin A (THG-A) is effective in treating the metabolic clinical condition caused by a high-fat diet. The body weight, epididymal adipose volume, alanine transaminase (ALT), total-cholesterol (T-CHO), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and glucose concentrations in serum increased in mice fed a high-fat diet compared to mice fed a control diet. On the other hand, adiponectin level in serum of mice fed a high-fat diet decreased compared to that of control mice. When mice fed a high-fat diet were intraperitoneally administered THG-A of 20 mg/kg three times per week, the levels of TG and glucose in serum were significantly reduced compared to those fed high-fat without THG-A. Interestingly, the levels of high-density lipoprotein cholesterol (HDL-C) in serum were increased by THG-A administration in both mice fed a control diet and those fed high-fat diet. The decreased level of adiponectin by a high-fat diet was also recovered by THG-A treatment. The liver expression of mRNA from pro-inflammatory cytokines, including interleukin (IL)-6 and tumor necrosis factor (TNF)-α, were significantly increased in mice fed a high-fat diet compared to those fed a control diet. However, the increased IL-6 levels in mice fed a high-fat diet were significantly suppressed by THG-A treatment. Furthermore, the increased expression of TNF-α mRNA or COL1A2 mRNA by a high-fat diets tended to be decreased in mice treated with THG-A. These results show that THG-A treatment attenuates the progression of metabolic clinical conditions, suggesting its potential efficacy against obesity-related metabolic disorders.

Influenza virus infection causes neutrophil dysfunction through reduced G-CSF production and an increased risk of secondary bacteria infection in the lung.

The immunological mechanisms of secondary bacterial infection followed by influenza virus infection were examined. When mice were intranasally infected with influenza virus A and then infected with P. aeruginosa at 4 days after viral infection, bacterial clearance in the lung significantly decreased compared to that of non-viral infected mice. Neutrophils from viral infected mice showed impaired digestion and/or killing of phagocytized bacteria due to reduced myeloperoxidase (MPO) activity. G-CSF production in the lungs of viral infected mice was lower than that of non-viral infected mice after secondary bacterial infection. When viral infected mice were injected with G-CSF before secondary bacterial infection, the MPO activity of viral infected mice restored to the same level as that of non-infected mice. Bacteria clearance in viral infected mice was also recovered by G-CSF administration. Thus, neutrophil dysfunction caused by influenza virus is attributed to insufficient G-CSF production, which induces a secondary bacterial infection.

Oral tolerance is inducible during active dextran sulfate sodium-induced colitis.

AIM: To investigate whether oral tolerance is inducible during the active phase of dextran sulfate sodium (DSS)-induced colitis. METHODS: Colitis was induced in 6- to 8-wk-old female BALB/c mice by the administration of 2% DSS. To induce oral tolerance, mice that received water with DSS [DSS (+)] and mice that received autoclaved water [DSS (-)] were intragastrically (i.g.) administered ovalbumin (OVA) as a tolerogen before systemic challenge with OVA. Following this, serum levels of OVA-specific IgE antibodies were measured. In mice with active colitis, CD4(+)CD25(+)Foxp3(+) cell and B10 cell frequencies were evaluated using flow cytometry. Cytokine mRNA expression profiles were evaluated by reverse transcription real-time polymerase chain reaction. RESULTS: Regardless of the presence of DSS colitis, OVA-specific immunoglobulin E concentrations were significantly reduced in mice that were i.g. administered OVA compared to mice that were i.g. administered PBS [DSS (+): 4.4 (4.2-9.5) ng/mL vs 83.9 (66.1-123.2) ng/mL, P < 0.01; DSS (-): 27.7 (0.1-54.5) ng/mL vs 116.5 (80.6-213.6) ng/mL, P < 0.01]. These results demonstrated that oral tolerance was induced in both the presence and absence of colitis. In the spleen and mesenteric lymph nodes (MLN), the frequencies of CD4(+)CD25(+)Foxp3(+) cells and B10 cells, both of which are associated with oral tolerance, did not significantly change. In the spleen, interferon-γ mRNA expression significantly decreased in mice with colitis [DSS (+): 0.42 (0.31-0.53) vs DSS (-): 1.00 (0.84-1.39), P < 0.01]. The expression levels of other cytokines did not significantly change. CONCLUSION: Oral tolerance is inducible during active DSS colitis. The stability of regulatory cell populations in the spleen and MLN in colitis might correlate with these results.

Effects of silica-coating on surface topography and bond strength of porcelain fused to CAD/CAM pure titanium.

The aim of this study was to evaluate the shear bond strength of porcelain fusing to titanium and the effects of surface treatment on surface structure of titanium. In the shear bond strength test, titanium surface treatments were: conventional, silica-coating without bonding agent, and silica-coating with bonding agent. Titanium surface treatments for analysis by the atomic force microscope (AFM) were: polishing, alumina sandblasting and silica-coating. The shear bond strength value of silica-coating with bonding agent group showed significantly higher than that of other groups. In AFM observation results, regular foamy structure which is effective for wetting was only observed in silica-coating. Therefore, this structure might indicate silicon. Silica-coating renders forms a nanoscopic regular foamy structure, involved in superhydrophilicity, to titanium surface, which is markedly different from the irregular surface generated by alumina sandblasting.

The protective effects of intranasal administration of IL-12 given before influenza virus infection and the negative effects of IL-12 treatment given after viral infection.

To investigate whether the administration of IL-12 is effective against influenza virus infection, mice were intranasally administered IL-12 for three consecutive days and then infected with a non-lethal dose of the influenza virus. The IL-12-treated mice were more resistant to the virus than control mice with respect to the remission of body weight loss, virus burden, pro-inflammatory cytokine production, and inflammatory cell infiltration in the lungs. The number of NK cells and the level of NK cell cytotoxicity significantly increased in the lungs of the mice treated with IL-12 before infection compared to that observed in control mice, leading to promptly eliminate the viral-infected cells. Unexpectedly, all of mice that received IL-12 treatment after being infected with a non-lethal dose of the virus died as a result of their high virus burden and pro-inflammatory cytokine production in the lungs. One possibility of the mechanisms was considered to be activation of myeloid-derived suppressor cell (MDSC), which has immune suppressive function, in the lungs. Thus, IL-12 treatment has opposite effects depending on whether it is administered before or after infection. These results demonstrate the potential risks of immune modulating therapies such as administration of exogenous cytokine or neutralization of cytokine. J. Med. Virol. 88:1487-1496, 2016. © 2016 Wiley Periodicals, Inc.

Severe refractory Clostridium difficile infection with good response to fecal microbiota transplantation: a case report.

A 49-year-old woman diagnosed with pseudomembranous enterocolitis was transferred to our hospital for medical treatment. She responded poorly to treatment with vancomycin hydrochloride and metronidazole, so she underwent fecal microbiota transplantation. Treatment effects were observed the next day, and the diarrhea disappeared within 3 days. Colonoscopy 4 days later revealed the resolution of pseudomembranes, and no recurrences were reported within the first year after discharge.

Successful conservative treatment of emphysematous gastritis.

Emphysematous gastritis is an extremely rare disease with an unfavorable prognosis. To date, very few studies have been conducted regarding the intragastric recovery process based on endoscopic findings. We herein report a case of emphysematous gastritis that improved with long-term (five months) conservative treatment in which we were able to observe the intragastric recovery process endoscopically. In cases in which emphysematous gastritis is suspected, it is important to provide prompt diagnostic imaging (including CT) and early appropriate treatment in order to improve the prognosis.

Clinical application of removable partial dentures using thermoplastic resin. Part II: Material properties and clinical features of non-metal clasp dentures.

This position paper reviews physical and mechanical properties of thermoplastic resin used for non-metal clasp dentures, and describes feature of each thermoplastic resin in clinical application of non-metal clasp dentures and complications based on clinical experience of expert panels. Since products of thermoplastic resin have great variability in physical and mechanical properties, clinicians should utilize them with careful consideration of the specific properties of each product. In general, thermoplastic resin has lower color-stability and higher risk for fracture than polymethyl methacrylate. Additionally, the surface of thermoplastic resin becomes roughened more easily than polymethyl methacrylate. Studies related to material properties of thermoplastic resin, treatment efficacy and follow-up are insufficient to provide definitive conclusions at this time. Therefore, this position paper should be revised based on future studies and a clinical guideline should be provided.

Clinical application of removable partial dentures using thermoplastic resin-part I: definition and indication of non-metal clasp dentures.

This position paper proposes a definition and naming standard for removable partial dentures (RPDs) using thermoplastic resin, and presents a guideline for clinical application. A panel of 14 experts having broad experience with clinical application of RPDs using thermoplastic resin was selected from members of the Japan Prosthodontic Society. At a meeting of the panel, "non-metal clasp denture" was referred as the generic name of RPDs with retentive elements (resin clasps) made of thermoplastic resin. The panel classified non-metal clasp dentures into two types: one with a flexible structure that lacks a metal framework and the other having a rigid structure that includes a metal framework. According to current prosthetic principles, flexible non-metal clasp dentures are not recommended as definitive dentures, except for limited cases such as patients with a metal allergy. Rigid non-metal clasp dentures are recommended in cases where patients will not accept metal clasps for esthetic reasons. Non-metal clasp dentures should follow the same design principles as conventional RPDs using metal clasps.

Repair of silorane-based composites: microtensile bond strength of silorane-based composites repaired with methacrylate-based composites.

The purpose of our study was to evaluate the effects of surface treatment on the microtensile bond strength (MTBS) of silorane-based composites (Filtek Silorane, 3M ESPE) repaired with methacrylate-based composites (Ceram X, Dentsply). The MTBS were measured before or after thermo-mechanical fatigue simulation (FS). The surface conditioning regimes were: no treatment, bonding agent, silane, and silane+bonding agent. Before and after FS, no significant differences could be observed among the different pretreatment groups. FS did not change the MTBS although FS increased the repair strength of Silorane in our previous study under the same conditions, and after FS all of the failure modes showed adhesive failure, which means that the repair bond strengths between silorane-based composite and methacrylate-based composite were not durable. In conclusion, within the limitations of this study, with this composite neither bonding agent nor silane contributed to an increase in the tensile strength.

Small intestinal obstruction caused by anisakiasis.

Small intestinal anisakiasis is a rare disease that is very difficult to diagnose, and its initial diagnosis is often surgical. However, it is typically a benign disease that resolves with conservative treatment, and unnecessary surgery can be avoided if it is appropriately diagnosed. This case report is an example of small intestinal obstruction caused by anisakiasis that resolved with conservative treatment. A 63-year-old man admitted to our department with acute abdominal pain. A history of raw fish (sushi) ingestion was recorded. Abdominal CT demonstrated small intestinal dilatation with wall thickening and contrast enhancement. Ascitic fluid was found on the liver surface and in the Douglas pouch. His IgE (RIST) was elevated, and he tested positive for the anti-Anisakis antibodies IgG and IgA. Small intestinal obstruction by anisakiasis was highly suspected and conservative treatment was performed, ileus tube, fasting, and fluid replacement. Symptoms quickly resolved, and he was discharged on the seventh day of admission. Small intestinal anisakiasis is a relatively uncommon disease, the diagnosis of which may be difficult. Because it is a self-limiting disease that usually resolves in 1-2 weeks, a conservative approach is advisable to avoid unnecessary surgery.

Examination of bond strength and mechanical properties of Y-TZP zirconia ceramics with different surface modifications.

The purpose of our study was to evaluate the effects of surface modifications on the bond strength between veneering porcelains and Yttria-stabilized tetragonal zirconia (Y-TZP). In a bond strength tests, the effect of control, 70 µm alumina-sandblasting, 30 µm and 110 µm silica-coating of the Y-TZP surface on bonding were evaluated with veneering porcelains. In addition, the effect of surface modification on the flexural strength of Y-TZP was also evaluated. The data was analyzed using one-way ANOVA and Tukey test. All specimens showed bond strength values in excess of 25 MPa, the minimum allowed by ISO9693. In addition, significantly differences were found between the control and the 30 µm silica-coated. On the other hand the flexural strength of Y-TZP does not significantly difference for any surface modification. These results indicate that silica-coating may provide an effective pre-treatment for this enhancement of the bond strength while maintaining the strength of Y-TZP.

Repair of silorane-based dental composites: influence of surface treatments.

OBJECTIVE: The purpose of our study was to evaluate the effects of surface treatment on the microtensile bond strength (MTBS) of repaired silorane-based composites (Filtek Silorane (Silorane), 3M ESPE). METHODS: The surfaces of the aged Silorane blocks (6 mm × 6 mm × 5 mm) were ground with 320-grit SiC paper. The subsequent surface treatments were: no treatment, bonding agent, acetone, acetone+bonding agent, ethanol, ethanol+bonding agent, silane and silane+bonding agent. Another group made from Silorane without repair served as positive control. New Silorane was bonded onto the treated samples. The MTBS test was performed (1mm/min) with beam-shaped sticks (1.0 mm × 1.0 mm × 10 mm) before and after fatigue simulation (FS). The Weibull moduli for the MTBS data were also calculated. The fracture modes were examined with an optical microscope. The aged specimens after grinding were observed in a SEM and the percentage of uncovered filler surface in relation to the whole surface was calculated. RESULTS: There were no significant differences between the no treatment group and the acetone only or ethanol only groups. Bonding agent improved the MTBS and the Weibull modulus. Although the SEM image revealed only 5.1% of uncovered filler surface, silane improved the MTBS. The groups with silane and bonding agent had the highest strength values except two groups and showed a fairly large number of cohesive failures. However, after FS, the differences between almost all groups were insignificant. FS increased the MTBS of almost all groups. SIGNIFICANCE: The application of silane and bonding agent enhanced the initial repair strength.