Effects of Red LED Irradiation in Enhancing the Mineralization of Human Dental Pulp Cells In Vitro.

Dentin regeneration is the preferred method used to preserve dental pulp vitality after pulp exposure due to caries. Red light-emitting diode irradiation (LEDI), which is based on photobiomodulation (PBM), has been used to promote hard-tissue regeneration. However, the underlying mechanism still needs elucidation. This study aimed to explore the mechanism involved in red LEDI affecting dentin regeneration. Alizarin red S (ARS) staining revealed that red LEDI induced mineralization of human dental pulp cells (HDPCs) in vitro. We further distinguished the cell proliferation (0-6 d), differentiation (6-12 d), and mineralization (12-18 d) of HDPCs in vitro and treated cells either with or without red LEDI in each stage. The results showed that red LEDI treatment in the mineralization stage, but not the proliferation or differentiation stages, increased mineralized nodule formation around HDPCs. Western blot also indicated that red LEDI treatment in the mineralization stage, but not the proliferation or differentiation stages, upregulated the expression of dentin matrix marker proteins (dentin sialophosphoprotein, DSPP; dentin matrix protein 1, DMP1; osteopontin, OPN) and an intracellular secretory vesicle marker protein (lysosomal-associated membrane protein 1, LAMP1). Therefore, the red LEDI might enhance the matrix vesicle secretion of HDPCs. On the molecular level, red LEDI enhanced mineralization by activating the mitogen-activated protein kinase (MAPK) signaling pathways (ERK and P38). ERK and P38 inhibition reduced mineralized nodule formation and the expression of relevant marker proteins. In summary, red LEDI enhanced the mineralization of HDPCs by functioning to produce a positive effect in the mineralization stage in vitro.

Pirfenidone Inhibits Alveolar Bone Loss in Ligature-Induced Periodontitis by Suppressing the NF-κB Signaling Pathway in Mice.

There has been increasing interest in adjunctive use of anti-inflammatory drugs to control periodontitis. This study was performed to examine the effects of pirfenidone (PFD) on alveolar bone loss in ligature-induced periodontitis in mice and identify the relevant mechanisms. Experimental periodontitis was established by ligating the unilateral maxillary second molar for 7 days in mice (n = 8 per group), and PFD was administered daily via intraperitoneal injection. The micro-computed tomography and histology analyses were performed to determine changes in the alveolar bone following the PFD administration. For in vitro analysis, bone marrow macrophages (BMMs) were isolated from mice and cultured with PFD in the presence of RANKL or LPS. The effectiveness of PFD on osteoclastogenesis, inflammatory cytokine expression, and NF-κB activation was determined with RT-PCR, Western blot, and immunofluorescence analyses. PFD treatment significantly inhibited the ligature-induced alveolar bone loss, with decreases in TRAP-positive osteoclasts and expression of inflammatory cytokines in mice. In cultured BMM cells, PFD also inhibited RANKL-induced osteoclast differentiation and LPS-induced proinflammatory cytokine (IL-1ß, IL-6, TNF-a) expression via suppressing the NF-κB signal pathway. These results suggest that PFD can suppress periodontitis progression by inhibiting osteoclastogenesis and inflammatory cytokine production via inhibiting the NF-κB signal pathway, and it may be a promising candidate for controlling periodontitis.

Body mass index and self-rated oral health in Korean adults in 2017.

OBJECTIVE: To investigate the association between obesity and self-rated oral health (SROH). This study examined the cross-sectional associations between body mass index (BMI) and SROH in Korean adults. MATERIALS AND METHODS: This study used data from 217 304 adults (100 110 men and 117 194 women aged > 19 years) from the 2017 Korean Community Health Survey. Participants were categorised into six ordinal groups based on BMI: underweight (<18.5 kg/m2 ), normal weight (18.5-22.9 kg/m2 ), overweight (23.0-24.9 kg/m2 ), obese-I (25.0-27.4 kg/m2 ), obese-II (27.5-29.9 kg/m2 ) or obese-III (≥30.0 kg/m2 ). SROH was assessed using responses to the question, "How do you rate your oral health, including your teeth and gums?" rated on a 5-point scale. SROH was categorised as "good" (reported as "fair," "good" or "very good") or "poor" or "very poor." Age- and sex-stratified associations between BMI categories and poor SROH were assessed using ordinal logistic regression analysis with sampling weights. RESULTS: The age-adjusted odds ratio (OR) for poor SROH according to BMI levels was lowest in the overweight group in both men and women. In men, the OR for poor SROH was 2.03 (99% confidence interval [CI], 1.72-2.39) in the underweight group, 1.17 (99% CI, 1.17-1.25) in the normal group, 1.05 (99% CI, 0.98-1.13) in the obese-I group, 1.08 (99% CI, 0.98-1.18) in the obese-II group and 1.36 (99% CI, 1.20-1.55) in the obese-III group. In women, the OR was 1.18 (99% CI, 1.07-1.31) in the underweight group, 1.01 (99% CI, 0.95-1.07) in the normal group, 1.07(99% CI, 0.99-1.16) in the obese-I group, 1.16 (99% CI, 1.04-1.30) in the obese-II group and 1.39 (99% CI, 1.20-1.62) in the obese-III group. From the restricted cubic spline models in both sexes, BMI showed a J-shaped association with poor and very poor SROH in men and women. In a stratified analysis by age group and sex, men and older women in the underweight group had poorer SROH than those in overweight group. CONCLUSION: In a nationally representative sample of Korean adults, there was a J-shaped association between BMI and poor SROH, with the highest risk in the underweight group amongst men and in the obese-III group amongst women. Furthermore, in men and women over 65 years of age, underweight and obesity were associated with poorer SROH.

Sclerostin in periodontal ligament: Homeostatic regulator in biophysical force-induced tooth movement.

AIM: To study the role of sclerostin in periodontal ligament (PDL) as a homeostatic regulator in biophysical-force-induced tooth movement (BFTM). MATERIALS AND METHODS: BFTM was performed in rats, followed by microarray, immunofluorescence, in situ hybridization, and real-time polymerase chain reaction for the detection and identification of the molecules. The periodontal space was analysed via micro-computed tomography. Effects on osteoclastogenesis and bone resorption were evaluated in the bone-marrow-derived cells in mice. In vitro human PDL cells were subjected to biophysical forces. RESULTS: In the absence of BFTM, sclerostin was hardly detected in the periodontium except in the PDL and alveolar bone in the furcation region and apex of the molar roots. However, sclerostin was up-regulated in the PDL in vivo by adaptable force, which induced typical transfiguration without changes in periodontal space as well as in vitro PDL cells under compression and tension. In contrast, the sclerostin level was unaffected by heavy force, which caused severe degeneration of the PDL and narrowed periodontal space. Sclerostin inhibited osteoclastogenesis and bone resorption, which corroborates the accelerated tooth movement by the heavy force. CONCLUSIONS: Sclerostin in PDL may be a key homeostatic molecule in the periodontium and a biological target for the therapeutic modulation of BFTM.

Activation and increased production of interleukin-17 and tumour necrosis factor-α of mucosal-associated invariant T cells in patients with periodontitis.

AIM: Mucosal-associated invariant T (MAIT) cells are known to be resident in oral mucosal tissue, but their roles in periodontitis are unknown. This study aimed to examine the level and function of MAIT cells in periodontitis patients. MATERIALS AND METHODS: Frequency, activation, and function of MAIT cells from 28 periodontitis patients and 28 healthy controls (HCs) were measured by flow cytometry. RESULTS: Circulating MAIT cells were numerically reduced in periodontitis patients. Moreover, they exhibited higher expression of CD69 and annexin V, together with more increased production of interleukin (IL)-17 and tumour necrosis factor (TNF)-α, in periodontitis patients than in HCs. Interestingly, periodontitis patients had higher frequencies of MAIT cells in gingival tissue than in peripheral blood. In addition, circulating MAIT cells had elevated expression of tissue-homing chemokine receptors such as CCR6 and CXCR6, and the corresponding chemokines (i.e., CCL20 and CXCL16) were more strongly expressed in inflamed gingiva than in healthy gingiva. CONCLUSIONS: This study demonstrates that circulating MAIT cells are numerically deficient with an activated profile toward the production of IL-17 and TNF-α in periodontitis patients. Furthermore, circulating MAIT cells have the potential to migrate to inflamed gingival tissues.

SLPI in periodontal Ligament is not sleepy during biophysical force-induced tooth movement.

AIM: We aimed to identify a key molecule that maintains periodontal tissue homeostasis during biophysical force-induced tooth movement (BTM) by orchestrating alveolar bone (AB) remodelling. MATERIALS AND METHODS: Differential display-PCR was performed to identify key molecules for BTM in rats. To investigate the localization and expression of the identified molecules, immunofluorescence, real-time RT-PCR and Western blotting were performed in rats and human periodontal ligament (PDL) cells. Functional test and micro-CT analysis were performed to examine the in vivo effects of the identified molecules on BTM. RESULTS: Secretory leucocyte peptidase inhibitor (SLPI) in the PDL was revealed as a key molecule for BTM-induced AB remodelling. SLPI was enhanced in the PDL under both compression and tension, and downregulated by an adenyl cyclases inhibitor. SLPI induced osteoblastogenic genes including runt-related transcription factor 2 (Runx2) and synergistically augmented tension-induced Runx2 expression. SLPI augmented mineralization in PDL cells. SLPI induced osteoclastogenic genes including receptor activator of nuclear factor kappa-Β ligand (RANKL) and synergistically augmented the compression-induced RANKL and macrophage colony-stimulating factor (MCSF) expression. Finally, the in vivo SLPI application into the AB significantly augmented BTM. CONCLUSIONS: SLPI or its inhibitors might serve as a biological target molecule for therapeutic interventions to modulate BTM.

Digital panoramic radiographs are useful for diagnosis of osteoporosis in Korean postmenopausal women.

OBJECTIVE: The purpose of this study was to determine whether digital panoramic radiographs could be used for the diagnosis of osteoporosis through evaluation of the radiographs based on the correlation with bone mineral density (BMD). METHODS: One hundred and ninety-four post-menopausal women were selected from participants who had participated in the Dong-gu study. Panoramic radiographic indices measured are mental index (MI), mandibular cortical index (MCI) and simple visual estimation (SVE). BMD at the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DXA). The Pearson's correlation test was performed to analyse the correlation between MI and age and BMD at the lumbar spine, femoral neck and total hip. Multiple linear regression analysis was performed to analyse the association of MI, MCI and SVE with BMD after adjusting for age, height and weight. To determine the optimal cut-off point of MI for the diagnosis of osteoporosis, the receiver operating characteristic analysis was performed. RESULTS: The MI was positively correlated with BMDs: lumbar spine: r = 0.36, femoral neck: r = 0.59 and total hip: r = 0.58 (p < 0.001). As age increased, MI decreased (r = -0.46). BMD at the lumbar spine and total hip were significantly lower in participants with reduction of mandibular width, thinning and resorption of mandibular cortex by the MI, SVE and MCI, respectively. The optimal cut-off value of MI for the diagnosis of spinal osteoporosis was 2.22 mm. CONCLUSION: Thickness and morphological changes of mandibular inferior cortical bone are associated with BMD, independent of age, height and weight. These results suggest that MI, MCI and SVE may be useful indices for the diagnosis of osteoporosis in a Korean population.

Periodontal disease associated with blood glucose levels in urban Koreans aged 50 years and older: the Dong-gu study.

OBJECTIVE: To investigate the association of periodontal disease and the number of teeth present with the risk of prediabetes and diabetes as well as with blood glucose and HbA1c levels in adult Koreans. BACKGROUND: The relationship between periodontal disease and diabetes has not been fully elucidated. MATERIALS AND METHODS: Cross-sectional data from 5535 participants aged ≥50 years were obtained from 2008 to 2010. Periodontal status was measured as pocket depth (PD), clinical attachment loss (CAL) and bleeding on probing (BOP) recorded. The percentage of sites with a PD ≥4 mm, CAL ≥4 mm (CAL4) and BOP (BOP%) were recorded. Participants were divided into three groups according to PD4, CAL4 and BOP% measurements. Number of teeth present was divided into four groups. Participants were classified as normoglycaemic, prediabetic or diabetic based on HbA1c and fasting glucose levels. RESULTS: After full adjustment, the highest tertile of CAL4 (OR: 1.47, 95% CI: 1.18-2.02, p < 0.001), PD4 (OR: 1.58, 95% CI: 1.26-1.97, p < 0.001) and BOP% (OR: 1.37, 95% CI: 1.07-1.75, p = 0.012) had significantly increased odds of diabetes. The number of teeth present was inversely related to diabetes (p < 0.001) and prediabetes (p = 0.032) risk. Periodontal disease severity was positively associated with HbA1c and glucose levels. The number of teeth present was positively associated with HbA1c, but not glucose, levels. CONCLUSION: Periodontal disease and the number of teeth present are associated with an increased risk of diabetes and increased blood glucose and HbA1c levels in Koreans aged ≥50 years.

The association between periodontal disease, tooth loss and bone mineral density in a Korean population.

OBJECTIVE: We aimed to evaluate whether clinical attachment loss (CAL), a measure of the severity of periodontal disease or number of teeth present is associated with bone mineral density (BMD). METHODS: The study population consisted of 5383 people aged 50 years and older who participated in the Dong-gu Study. BMD at the lumbar spine and femoral neck was measured by dual-energy X-ray absorptiometry. Oral examination included assessments of the number of teeth present and CAL. Number of teeth present was categorized into three equal categories. CAL values were divided into tertiles in terms of the percentage of sites with CAL ≥4 mm. Analysis of covariance was used to compare the adjusted means of BMD according to the tooth number and the tertiles of CAL. RESULTS: There was a significant association between the number of teeth present and BMD in men. Compared with men with 22 or more teeth, men with 10 and less teeth had lower BMD. CAL was significantly associated with lower BMD at the lumbar spine in women. CONCLUSION: Our data indicate that tooth loss and CAL were associated with low BMD. However, the magnitude of these associations was relatively small and the clinical significance was unclear.

Relationship between periodontal disease and subclinical atherosclerosis: the Dong-gu study.

AIM: We assessed the association of periodontal disease and number of missing teeth with subclinical atherosclerosis in an adult Korean population. MATERIALS AND METHODS: Cross-sectional data from 5404 individuals aged ≥50 years were obtained from the 2008-2010 Dong-gu study. Periodontal examinations were conducted to determine the number of missing teeth, pocket depth (PD), clinical attachment loss (CAL), and bleeding on probing (BOP). The percentages of sites with PD ≥ 4 mm (PD 4%), CAL ≥ 4 mm (CAL 4%), and BOP (BOP%) were recorded for each participant. B-mode ultrasound was performed to determine common carotid artery intima-media thickness (CCA IMT) and the presence of carotid plaques. Multivariate linear regression models were used to assess the associations between periodontal parameters and CCA IMT and carotid plaque. RESULTS: Number of missing teeth was associated with increased CCA IMT, and BOP% was associated with increased CCA IMT in females only. This association was robust in never smokers. CONCLUSIONS: The number of missing teeth was associated with CCA IMT, and BOP% was associated with CCA IMT in females only. These associations were robust in never smokers. Our results suggest that tooth loss due to oral disease may play a role in subclinical carotid atherosclerosis.

Effect of surface treatment on bond strength of Ti-10Ta-10Nb to low-fusing porcelain.

STATEMENT OF PROBLEM: Ti-10Ta-10Nb alloy is a promising alloy for metal ceramic crowns because of its good corrosion resistance and low cytotoxicity. However, more information is needed on the bond strength between this alloy and porcelain. PURPOSE: The purpose of this study was to compare the surface morphology, surface roughness, and bond strength of a Ti-10Ta-10Nb alloy, pure Ti, and a Ti-6Al-4V alloy. MATERIAL AND METHODS: Ti-10Ta-10Nb, pure Ti, and Ti-6Al-4V specimens (25 × 3 × 0.55 mm plate) were prepared and then divided into 6 groups (n=8) according to surface treatment. Group P (control group) was polished with SiC paper. Groups S50 and S250 were airborne-particle abraded with 50 µm and 250 µm aluminum oxide powder. Group HCl was immersed in 10% HCl aqueous solution, and Group HF was immersed in 17% HNO(3)/HF solution. Group TiN was coated with TiN. Atomic force microscopy was used to observe the surface roughness of the metal surface. Scanning electron microscopy was used to analyze the surface profile. A 3-point bending test was performed to evaluate the bond strength. Two-way analysis of variance (ANOVA) was performed to compare the roughness and bond strength and statistical differences were revealed by the Bonferroni post hoc test (α=.05). RESULTS: There were significant differences in the surface roughness, surface profile, and bond strength of the Ti alloys according to the surface treatments. The groups with the higher mean surface roughness showed higher bond strength, but surface profile had a larger effect on the bond strength than surface roughness. Moreover, the bond strength of the Ti-10Ta-10Nb alloy was high. CONCLUSIONS: Ti-10Ta-10Nb would be more suitable for a metal ceramic crown than pure Ti or Ti-6Al-4V, which have limited use because of their low bond strength to porcelain.

Autophagy upregulates inflammatory cytokines in gingival tissue of patients with periodontitis and lipopolysaccharide-stimulated human gingival fibroblasts.

BACKGROUND: Periodontitis is an inflammatory disease caused by multiple disease-associated bacterial species in periodontal tissues. Autophagy is known to modulate various inflammation-driven diseases and inflammatory responses, but the role of autophagy related to the pathogenesis of periodontitis is not fully established. We investigated whether autophagic flux regulated the expression of inflammatory cytokines in the gingiva of periodontitis patients and lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (HGFs) and the underlying mechanism. METHODS: The mRNA and protein expression of proinflammatory cytokines was assessed in human gingival tissues collected from patients with periodontitis and HGFs treated with LPS. The expression of signaling molecules related to autophagy was evaluated by immunofluorescence and Western blot analyses. RESULTS: The expression of interleukin (IL)-6, tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), and intercellular adhesion molecule-1 (ICAM-1) was increased in the gingival tissues of patients with periodontitis. LC3B-positive cells, a typical autophagic marker, were increased in the gingival tissues of periodontitis patients and LPS-treated HGFs. The conversion ratio of LC3-I to LC3-II was higher in the gingival tissues associated with periodontitis and LPS-treated HGFs compared to the controls. The autophagy inhibitor 3-methyladenine (3MA) significantly abrogated the LPS-sustained inflammatory effect by reducing the expression of IL-6, TNF-α, COX-2, and ICAM-1 in HGFs. The phosphorylation of protein kinase B (AKT) and protein S6K1 (S6), signals involved in the mTOR-dependent mechanism, was decreased in gingiva derived from periodontitis patients and LPS-treated HGFs. CONCLUSIONS: Autophagy augmented the production of inflammatory cytokines by mTOR inactivation via the AKT signaling pathway in the gingival tissues of patients with periodontitis and LPS-stimulated HGFs. These findings would provide a better understanding of the mechanism by which autophagy regulates the inflammatory response associated with periodontal pathogenesis.

Isolation of High Purity Mouse Mesenchymal Stem Cells through Depleting Macrophages Using Liposomal Clodronate.

BACKGROUND: The use of mouse bone marrow mesenchymal stem cells (mBMSCs) represents a promising strategy for performing preclinical studies in the field of cell-based regenerative medicine; however, mBMSCs obtained via conventional isolation methods have two drawbacks, i.e., (i) they are heterogeneous due to frequent macrophage contamination, and (ii) they require long-term culturing for expansion. METHODS: In the present study, we report a novel strategy to generate highly pure mBMSCs using liposomal clodronate. This approach is based on the properties of the two cell populations, i.e., BMSCs (to adhere to the plasticware in culture dishes) and macrophages (to phagocytose liposomes). RESULTS: Liposomal clodronate added during the first passage of whole bone marrow culture was selectively engulfed by macrophages in the heterogeneous cell population, resulting in their effective elimination without affecting the MSCs. This method allowed the generation of numerous high-purity Sca-1+CD44+F4/80- mBMSCs (> 95%) with just one passaging. Comparative studies with mBMSCs obtained using conventional methods revealed that the mBMSCs obtained in the present study had remarkably improved experimental utilities, as demonstrated by in vitro multilineage differentiation and in vivo ectopic bone formation assays. CONCLUSION: Our newly developed method, which enables the isolation of mBMSCs using simple and convenient protocol, will aid preclinical studies based on the use of MSCs.

Effect of a Er, Cr:YSGG laser and a Er:YAG laser treatment on oral biofilm-contaminated titanium.

OBJECTIVE: Implant surface decontamination is a challenging procedure for therapy of peri-implant disease. This study aimed to compare the effectiveness of decontamination on oral biofilm-contaminated titanium surfaces in Er:YAG laser, Er, Cr:YSGG laser, and plastic curette. METHODOLOGY: For oral biofilms formation, six participants wore an acrylic splint with eight titanium discs in the maxillary arch for 72 hours. A total of 48 contaminated discs were distributed among four groups: untreated control; decontamination with plastic curettes; Er, Cr:YSGG laser; and Er:YAG laser irradiation. Complete plaque removal was estimated using naked-eye and the time taken was recorded; the residual plaque area was measured and the morphological alteration of the specimen surface was observed by scanning electron microscopy. The total bacterial load and the viability of adherent bacteria were quantified by live or dead cell labeling with fluorescence microscopy. RESULTS: The mean treatment time significantly decreased based on the treatment used in the following order: Er:YAG, Er, Cr:YSGG laser, and plastic curettes (234.9±25.4 sec, 156.1±12.7 sec, and 126.4±18.6 sec, P=0.000). The mean RPA in the Er, Cr:YSGG laser group (7.0±2.5%) was lower than Er:YAG and plastic curettes groups (10.3±2.4%, 12.3±3.6%, p=0.023). The viable bacteria on the titanium surface after Er, Cr:YSGG laser irradiation was significantly lower compared to the decontamination with plastic curette (P=0.05) but it was not significantly different from the Er:YAG laser irradiation. CONCLUSION: We found that Er:YAG laser and Er, Cr:YSGG laser irradiation were effective methods for decontaminations without surface alterations.

Low serum 25-hydroxyvitamin D levels, tooth loss, and the prevalence of severe periodontitis in Koreans aged 50 years and older.

PURPOSE: Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss. METHODS: Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008-2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions. Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed. RESULTS: Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis. CONCLUSIONS: This population-based cross-sectional study indicates that low serum 25(OH)D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.

Antibacterial activity of pyrrolidine dithiocarbamate.

Pyrrolidine dithiocarbamate (PDTC), an antioxidant with a metal-chelating activity, has been used widely to inhibit the expression of inflammatory genes in vitro and in vivo. This study investigated whether PDTC has an antimicrobial activity against various bacteria. The antibacterial activity of PDTC and other compounds was evaluated in vitro by the broth microdilution method against Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Staphylococcus aureus, and Escherichia coli. Bacterial growth was inhibited by PDTC, where a wide range of sensitivity was demonstrated among the tested bacteria. The antibacterial activity of PDTC was reduced by the addition of copper chloride; in contrast, it was enhanced considerably by zinc chloride. Two different zinc chelators, Ca-saturated EDTA (Ca-EDTA) and N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine, blocked the antibacterial activity of PDTC, whereas Zn-EDTA failed to reduce the activity of PDTC. These results demonstrate for the first time that PDTC possesses an antibacterial activity, for which zinc is required, and suggest that PDTC, possessing a dual anti-inflammatory and antibacterial activity, may be considered for topical use for inflammatory diseases of bacterial origin.

Effect of a Er, Cr: YSGG laser and a Er: YAG laser treatment on oral biofilm-contaminated titanium

Abstract Implant surface decontamination is a challenging procedure for therapy of peri-implant disease. Objective: This study aimed to compare the effectiveness of decontamination on oral biofilm-contaminated titanium surfaces in Er:YAG laser, Er, Cr:YSGG laser, and plastic curette. Methodology: For oral biofilms formation, six participants wore an acrylic splint with eight titanium discs in the maxillary arch for 72 hours. A total of 48 contaminated discs were distributed among four groups: untreated control; decontamination with plastic curettes; Er, Cr:YSGG laser; and Er:YAG laser irradiation. Complete plaque removal was estimated using naked-eye and the time taken was recorded; the residual plaque area was measured and the morphological alteration of the specimen surface was observed by scanning electron microscopy. The total bacterial load and the viability of adherent bacteria were quantified by live or dead cell labeling with fluorescence microscopy. Results: The mean treatment time significantly decreased based on the treatment used in the following order: Er:YAG, Er, Cr:YSGG laser, and plastic curettes (234.9±25.4 sec, 156.1±12.7 sec, and 126.4±18.6 sec, P=0.000). The mean RPA in the Er, Cr:YSGG laser group (7.0±2.5%) was lower than Er:YAG and plastic curettes groups (10.3±2.4%, 12.3±3.6%, p=0.023). The viable bacteria on the titanium surface after Er, Cr:YSGG laser irradiation was significantly lower compared to the decontamination with plastic curette (P=0.05) but it was not significantly different from the Er:YAG laser irradiation. Conclusion: We found that Er:YAG laser and Er, Cr:YSGG laser irradiation were effective methods for decontaminations without surface alterations.

Humoral immune responses to periodontal pathogens in the elderly.

PURPOSE: Elderly people are thought to be more susceptible to periodontal disease due to reduced immune function associated with aging. However, little information is available on the nature of immune responses against putative periodontal pathogens in geriatric patients. The purpose of this study was to evaluate the serum IgG antibody responses to six periodontal pathogens in geriatric subjects. METHODS: The study population consisted of 85 geriatric patients and was divided into three groups: 29 mild (MCP), 27 moderate (MoCP) and 29 severe (SCP) chronic periodontitis patients. Serum levels of IgG antibody to Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Prevotella intermedia were measured by enzyme-linked immunosorbent assay (ELISA) and compared among the groups. RESULTS: All three groups showed levels of serum IgG in response to P. gingivalis, A. actinomycetemcomitans, and P. intermedia that were three to four times higher than levels of IgG to T. forsythia, T. denticola, and F. nucleatum. There were no significant differences among all three groups in IgG response to P. gingivalis (P=0.065), T. forsythia (P=0.057), T. denticola (P=0.1), and P. intermedia (P=0.167), although the IgG levels tended to be higher in patients with SCP than in those with MCP or MoCP (with the exception of those for P. intermedia). In contrast, there were significant differences among the groups in IgG levels in response to F. nucleatum (P=0.001) and A. actinomycetemcomitans (P=0.003). IgG levels to A. actinomycetemcomitans were higher in patients with MCP than in those with MoCP or SCP. CONCLUSIONS: When IgG levels were compared among three periodontal disease groups, only IgG levels to F. nucleatum significantly increased with the severity of disease. On the contrary, IgG levels to A. actinomycetemcomitans decreased significantly in patients with SCP compared to those with MCP. There were no significant differences in the IgG levels for P. gingivalis, T. forsythia, T. denticola, and P. intermedia among geriatric patients with chronic periodontitis.

The correlation of carotid artery calcification on panoramic radiographs and determination of carotid artery atherosclerosis with ultrasonography.

OBJECTIVES: To investigate the association of carotid artery calcification (CAC) on panoramic radiographs and determine carotid artery atherosclerosis with ultrasonography. STUDY DESIGN: The study included 4050 subjects aged 50 years and older. Panoramic radiographs for the presence of CAC were interpreted. Common carotid artery intima-media thickness (CCA-IMT), carotid bulb IMT (CB-IMT), carotid plaques, and the diameter of the common carotid artery (CCA-diameter) were measured by using ultrasonography. RESULTS: CB-IMT was significantly greater in male subjects with CAC than in those without CAC. CCA-diameter was significantly greater in subjects with CAC than in those without CAC in both genders. However, there was no significant difference in CCA-IMT. CAC was associated with carotid plaque (for men, odds ratio [OR] 2.14; 95% confidence interval [CI] 1.01-3.36; for women, OR 1.19; 95% CI 0.84-1.67). CONCLUSION: CAC on panoramic radiographs was positively associated with IMT and plaque in men and positively associated with carotid diameter in both sexes. CAC on panoramic radiographs was positively associated with carotid atherosclerosis.

Quantitative analysis of periodontal pathogens present in the saliva of geriatric subjects.

PURPOSE: At present, information regarding periodontal disease in geriatric patients is scarce. The purpose of this study was to quantify the periodontal pathogens present in the saliva of Korean geriatric patients and assess the relationship between the bacterial levels and the periodontal condition. METHODS: Six putative periodontal pathogens were quantified by using a real-time polymerase chain reaction assay in geriatric patient groups (>60 years) with mild chronic periodontitis (MCP), moderate chronic periodontitis (MoCP), and severe chronic periodontitis (SCP). The copy numbers of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Prevotella intermedia were measured. RESULTS: It was found that the bacterial copy numbers increased as the severity of the disease increased from MCP to SCP, except for P. intermedia. For P. intermedia, it was found that samples in the MCP group yielded the largest amount. It was also found that the quantities of P. gingivalis, T. forsythia, and T. denticola, the so-called "red complex" bacteria, were lower than those of F. nucleatum, A. actinomycetemcomitans, and P. intermedia in all of the samples. CONCLUSIONS: Collectively, the results of this study suggest that the levels of P. gingivalis, T. forsythia, F. nucleatum, and T. denticola present in saliva are associated with the severity of periodontal disease in geriatric patients.