Interaction between serum vitamin C levels and smoking on the periodontal condition in older adults.

BACKGROUND AND OBJECTIVES: Several epidemiological studies have reported that smokers have a higher prevalence and severity of periodontal disease than do nonsmokers, and that smoking negatively affects nutritional status and is associated with a reduced intake of antioxidants, particularly vitamin C. The present investigation aimed to examine the relationship between serum vitamin C levels and smoking and its influence on the periodontal condition in older adults. MATERIALS AND METHODS: A total of 353 respondents met the inclusion criteria and were enrolled in the present study. The periodontal status of the study participants was determined through examinations of one or more residual teeth, which included a measurement of the probing pocket depth (PPD) and clinical attachment level (CAL) at six regions of each tooth. Blood samples were collected during the dental examinations and then sent to a laboratory to evaluate serum vitamin C and cotinine levels. A serum cotinine concentration of 100 ng/ml was considered a relevant threshold for active smoking. After dividing the participants into two groups according to serum cotinine levels, Poisson regression analysis was carried out to compare vitamin C levels with the prevalence rate ratio (PRR) for periodontal condition markers for each group based on serum cotinine levels. RESULTS: We evaluated differences in the PRR of serum vitamin C tertiles between participants with high (≥100 ng/ml) or low (<100 ng/ml) serum cotinine levels after adjusting for sex, the use of interdental brushes or dental floss, and the number of teeth. A negative tendency between the PRR of vitamin C tertiles for the PPD or CAL was seen for both groups. Especially, a bigger difference was observed in the group with high serum cotinine levels. The PRR of the first tertiles in the high serum cotinine group was 5.03, compared with 2.69 in the low serum cotinine group (relative risk: 1.9). CONCLUSION: The results of this study suggest a potential association between vitamin C levels and the periodontal condition, which may be influenced by smoking status.

Sleep duration and severe periodontitis in middle-aged Japanese workers.

AIM: To evaluate the association between sleep duration and severe periodontitis in Japanese workers. MATERIALS AND METHODS: This cross-sectional study included 1130 workers (mean age 43.0 years) who underwent full-mouth periodontal examinations and health check-ups and completed a self-administered questionnaire that included questions on sleep duration. Logistic regression and a restricted cubic spline model were used to analyse the data. RESULTS: Severe periodontitis was identified in 6.3% of the study population. Those with <5, 5-5.9, 6-6.9, 7-7.9, and ≥8 hr of sleep were 6.7%, 17.4%, 40.3%, 26.3%, and 8.9%, respectively. After adjusting for potential confounders, study participants who slept <5 hr were more likely to have severe periodontitis (adjusted odds ratio = 2.64; 95% confidence interval = 1.06-6.60) than those who slept 7-7.9 hr. The spline model, with a reference value of 399 min (the median sleep duration), showed a non-linear association between sleep duration and severe periodontitis, where an increased prevalence of severe periodontitis was observed only among those with a shorter sleep duration. The prevalence of severe periodontitis did not increase with longer sleep duration. CONCLUSIONS: Short sleep duration was associated with severe periodontitis in this cohort of Japanese adults.

Interruption of regular dental visits during the COVID-19 pandemic due to concerns regarding dental visits was associated with periodontitis in Japanese office workers.

OBJECTIVE: To investigate the interrelationships among concerns regarding dental visits, the status of regular dental visits, and periodontal health during the coronavirus disease 2019 (COVID-19) pandemic. BACKGROUND: Continuous oral health care and regular dental visits are important for maintaining periodontal health. Due to the possibility of contracting COVID-19, individuals have been reluctant to visit medical institutions. It is unclear how the periodontal health of the Japanese population has been affected by the interruption of regular dental visits during the COVID-19 pandemic and how concerns regarding dental visits have affected attendance at regular dental visits. METHODS: This study included 199 Japanese office workers in one municipal office at Fukuoka Prefecture, Japan (average age = 42.6 years; age range = 19-77 years; 123 men and 76 women). Periodontitis was defined based on a full-mouth periodontal examination. The status of regular dental visits during the COVID-19 pandemic and concerns regarding dental visits were obtained via questionnaire. We tested the hypothesis that concerns regarding dental visits would indirectly affect periodontal health through the interruption of regular dental visits during the COVID-19 pandemic. We used mediation analysis, in which concerns regarding dental visits (present or absent) were set as the exposure, periodontitis (present or absent) was set as the outcome, and the status of regular dental visits (continued during the COVID-19 pandemic or not) was set as the mediator. RESULTS: Of the 199 study participants, 108 had a habit of attending regular dental visits. Of these, 31 (28.7%) discontinued regular dental visits during the COVID-19 pandemic. Compared to the individuals who continued regular dental visits, those who discontinued regular dental visits had a higher prevalence of periodontitis (49.4% vs 77.4%, p < 0.05) and concerns regarding dental visits (22.1% vs 64.5%, p < 0.05). Discontinuing regular dental visits significantly mediated the association between concerns regarding dental visits and periodontitis (natural indirect effect: odds ratio = 1.68, 95% confidence interval = 1.02-2.79, proportion mediated = 64.3%). CONCLUSION: The study results showed that individuals who discontinued regular dental visits during the COVID-19 pandemic due to concerns regarding dental visits had relatively poor periodontal health.

RNA-sequencing reveals positional memory of multipotent mesenchymal stromal cells from oral and maxillofacial tissue transcriptomes.

BACKGROUND: Multipotent mesenchymal stromal cells (MSCs) can be isolated from numerous tissues and are attractive candidates for therapeutic clinical applications due to their immunomodulatory and pro-regenerative capacity. Although the minimum criteria for defining MSCs have been defined, their characteristics are known to vary depending on their tissue of origin. RESULTS: We isolated and characterized human MSCs from three different bones (ilium (I-MSCs), maxilla (Mx-MSCs) and mandible (Md-MSCs)) and proceeded with next generation RNA-sequencing. Furthermore, to investigate the gene expression profiles among other cell types, we obtained RNA-seq data of human embryonic stem cells (ESCs) and several types of MSCs (periodontal ligament-derived MSCs, bone marrow-derived MSCs, and ESCs-derived MSCs) from the Sequence Reads Archive and analyzed the transcriptome profile. We found that MSCs derived from tissues of the maxillofacial region, such as the jaw bone and periodontal ligament, were HOX-negative, while those derived from other tissues were HOX-positive. We also identified that MSX1, LHX8, and BARX1, an essential regulator of craniofacial development, were strongly expressed in maxillofacial tissue-derived MSCs. Although MSCs may be divided into two distinct groups, the cells originated from over the neck or not, on the basis of differences in gene expression profile, the expression patterns of all CD antigen genes were similar among different type of MSCs, except for ESCs. CONCLUSIONS: Our findings suggest that MSCs from different anatomical locations, despite meeting general characterization criteria, have remarkable differences in gene expression and positional memory. Although stromal cells from different anatomical sources are generally categorized as MSCs, their differentiation potential and biological functions vary. We suggested that MSCs may retain an original tissue memory about the developmental process, including gene expression profiles. This could have an important impact when choosing an appropriate cell source for regenerative therapy using MSCs.

A natural anti-periodontitis agent, epimedokoreanin B, inhibits virulence activities of gingipains from Porphyromonas gingivalis.

Gingipains are potent virulence cysteine proteases secreted by Porphyromonas gingivalis, a major pathogen of periodontitis. We previously reported that epimedokoreanin B inhibits the activities of gingipains. In this report, we show that epimedokoreanin B inhibits the virulence of gingipains-containing P. gingivalis culture supernatants, indicating the potential use of this prenylated flavonoid as a new agent to combat against periodontal pathogens.

Fibroblast VEGF-receptor 1 expression as molecular target in periodontitis.

AIM: Degradation of extracellular matrices is an integral part in periodontitis. For antagonizing this pathophysiological mechanism, we aimed at identifying gene expression profiles in disease progression contributing periodontitis-associated fibroblasts (PAFs) versus normal gingival fibroblasts to determine their molecular repertoire, and exploit it for therapeutic intervention. MATERIALS AND METHODS: Applying an exploratory analysis using a small number of microarrays in combination with a three dimensional (3D) in vitro culture model that incorporates some aspects of periodontitis, PAFs were initially characterized by gene-expression analyses, followed by targeted gene down-regulation and pharmacological intervention in vitro. Further, immunohistochemistry was applied for phosphorylation analyses in tissue specimens. RESULTS: PAFs were characterized by 42 genes being commonly up-regulated >1.5-fold, and by five genes that were concordantly down-regulated (<0.7-fold). Expression of vascular endothelial growth factor (VEGF)-receptor 1 (Flt-1) was highly enhanced, and was thus further explored in in vitro culture models of periodontal fibroblasts without accounting for the microbiome. Phosphorylation of the VEGF-receptor 1 was enhanced in PAFs. Receptor inhibition by a specific VEGF-receptor inhibitor or intrinsic down-regulation by RNAi of the VEGF-receptor kinase in 3D gel cultures resulted in significant reduction in collagen degradation associated with increased tissue inhibitor of metalloproteinase expression, suggesting that Flt-1 may contribute to periodontitis. CONCLUSION: Based on the finding that VEGF-receptor kinase inhibition impaired collagen degradation pathways, Flt-1 may represent a candidate for therapeutic approaches in periodontitis.

The potential positive effect of periodontal treatment on brain function activity using functional magnetic resonance imaging analysis.

Background/purpose: There are reports on the relationship between periodontal treatment and the whole body. The purpose of the present study was to investigate the effect of periodontal initial treatment on brain function activity by improving periodontal tissue and the occlusal status of subjects with periodontitis. Materials and methods: The subjects were 13 patients with periodontitis. Following the patient's informed written consent, the periodontal initial treatment provided to the patient included tooth brushing instruction, scaling and root planning, however, occlusal adjustment was not performed at this stage. Periodontal examination, occlusal force examination and fMRI results were also evaluated at the initial and the reevaluation examinations. Results: After the periodontal initial treatment had been performed, periodontal tissue had significantly improved. In addition, cerebral blood flow in the insula and primary motor cortex was also improved, as confirmed by fMRI. Conclusion: This result suggests that the periodontal ligament has recovered and the periodontal ligament neuron have been further subjected to clenching in the insula.

The crystalline phase of cellulose changes under developmental control in a marine chordate.

The native form of cellulose is a fibrillar composite of two crystalline phases, the triclinic I(α) and monoclinic I(ß) allomorphs. Allomorph ratios are species-specific, and this gives rise to natural structural variations in cellulose crystals. However, the mechanisms contributing to crystal formation remain unknown. We show that the two crystalline phases of cellulose are tailored to distinct structures during different developmental stages of the tunicate chordate Oikopleura dioica. Larval cellulose consisting of I(α) allomorph constitutes the body cuticle fin, whereas adult cellulose consisting of I(ß) allomorph frames a mucous filter-feeding device, the "house." Both structures are secreted from the epidermis in accordance with the mutually exclusive expression patterns of two distinct putative cellulose synthase genes. We discuss a possible linkage between structural variations of the crystalline phases of cellulose and the underlying evolutionary genetics of cellulose biosynthesis.

The Ability of a Novel Trypsin-like Peptidase Activity Assay Kit to Detect Red-Complex Species.

The trypsin-like peptidase activity assay kit measures the trypsin-like protease produced by three red-complex species, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, causing periodontitis, and detects the presence of these bacteria in samples. The purpose of this study was to investigate the relationship between the detection of TLPs by a novel TLP-AA, ADCHECK and the detection of red-complex pathogens by real-time PCR using tongue swabs from patients with periodontitis. The detection limit of trypsin-like protease activity by ADCHECK was validated using the culture supernatants of two different Porphyromonas gingivalis bacterial strains. Real-time PCR was performed to determine the number of red-complex species in the tongue coatings of patients with periodontal disease. Trypsin-like protease activity in tongue-swab samples was scored using ADCHECK. ADCHECK successfully detected trypsin-like protease activity in 103 Porphyromonas gingivalis bacterial strains. The specificity, positive predictive value, negative predictive value, and accuracy of ADCHECK for the presence of red-complex pathogens determined by real-time PCR were 90%, 97%, 98%, and 92%, respectively. ADCHECK is an effective tool for the detection of red-complex pathogens.

The Alteration of Brain Function by the Improvement of Periodontal Tissues and Occlusal State.

Objective: In this study, we have introduced a case in which the effective blood oxygenation level-dependent signal on functional magnetic resonance imaging (fMRI) was altered by the improvement of periodontal tissue and occlusal function in a patient with periodontitis Stage II Grade B. Material and Methods. A 61-year-old female patient requiring periodontal treatment was diagnosed as having periodontitis Stage II Grade B via clinical and radiographic examinations. Her past medical history included type 2 diabetes, hypertension, and hyperlipidemia. Following the patient's informed written consent, the periodontal initial treatment provided to the patient included tooth brushing instruction and scaling and root planing; however, occlusal adjustment was not performed at this stage. Occlusal force and fMRI results were also evaluated at the initial and reevaluation examinations. Results: After the periodontal initial treatment had been performed, it was noted that the patient's periodontal tissue and occlusal force had improved. It was also evident from fMRI that cerebral blood flow had been activated in the insula, primary motor cortex, and premotor cortex. Conclusion: This result suggested that the periodontal ligament had recovered and the periodontal ligament neuron had been further subjected to clenching in the insula so that the muscle spindle sensation impacted the motor cortex.

Vignacyanidin Polyphenols Isolated from Vigna Angularis Bean Promote Osteoblast Differentiation.

BACKGROUND/AIM: An effective bone regenerative method needs to be established for the dental field. To identify a novel osteogenic factor for bone regeneration, we examined the effect of vignacyanidin (VIG) on osteoblastogenesis. MATERIALS AND METHODS: W20-17 cells, MC3T3-E1 cells, and primary cultured murine calvarial osteoblasts were used. Osteoblast differentiation was stimulated by ß-glycerophosphate, ascorbic acid, or bone morphogenetic protein (BMP)-4. Adipogenesis was induced using dexamethasone, 3-isobutyl-1-methylxanthine, insulin, and rosiglitazone. Differentiation or proliferation markers were determined using western blotting and/or the quantitative reverse transcription polymerase chain reaction. Adipogenic cells were visualized by Oil Red O staining. RESULTS: VIG treatment increased the expression of osteoblastic markers and alkaline phosphatase activity of osteoblast-lineage cells in a concentration-dependent manner. However, adipogenesis and cell proliferation were not affected by VIG. CONCLUSION: VIG treatment promoted osteoblast differentiation in osteoblast-lineage cells.

Evaluation of the ability of the trypsin-like peptidase activity assay to detect severe periodontitis.

OBJECTIVES: N-benzoyl-DL-arginine peptidase (trypsin-like peptidase) is specifically produced by certain strains of periodontitis-associated bacteria. We aimed to examine the effectiveness of an objectively quantified trypsin-like peptidase activity assay (TLP-AA) for detecting severe periodontitis. METHODS: The study population included 347 adults (108 men and 239 women; average age, 43.3 years) who underwent a full-mouth periodontal examination. Specimens for the TLP-AA were obtained using tongue swabs. Using a color reader, the TLP-AA results were obtained as a* values, with higher positive a* values indicating an increased intense enzymatic activity. The predictive validity of the TLP-AA results for severe periodontitis was assessed using receiver operating characteristic curve analysis and the periodontitis case definition provided by the Centers for Disease Control and Prevention/American Academy of Periodontology as the gold standard. Furthermore, multivariable logistic regression analyses were performed to predict severe periodontitis using the TLP-AA results and health characteristics, as the exposure variables. RESULTS: Severe periodontitis was observed in 5.2% of the participants. TLP-AA had high diagnostic accuracy for severe periodontitis, with an area under the curve of 0.83 (95% confidence interval [CI]: 0.75-0.92). The cut-off score for the a* value that best differentiated individuals with severe periodontitis was 0.09, with a sensitivity of 83% and specificity of 77%. Multivariable logistic regression analyses revealed that the TLP-AA results were significantly associated with severe periodontitis after adjusting for health characteristics (adjusted odds ratios: 1.90 [95% CI: 1.37-2.62] for the a* value). CONCLUSIONS: Objectively quantified TLP-AA results are potentially useful for detecting severe periodontitis in epidemiological surveillance.

Schizophyllum commune ß-glucan: Effect on interleukin-10 expression induced by lipopolysaccharide from periodontopathic bacteria.

ß-glucans are potent immunomodulators, with effects on innate and adaptive immune responses via dectin-1 as the main receptor. In this study, we investigated the biological effect of ß-glucan from Schizophyllum commune, called Schizophyllan (SPG) on Interleukin-10 (IL-10) expression induced by a lipopolysaccharide (LPS) from Aggregatibacter actinomycetemcomitans in murine macrophages (J774.1). SPG and dectin-1 interaction up-regulates LPS-induced IL-10 expression. The regulative effect of SPG on IL-10 expression is dependent on prolongation of nuclear translocation activity of nuclear factor-kappa B (NF-κBα) pathway induced by LPS. We also found that LPS-induced phosphorylation of mitogen- and stress-activated protein kinase 1 (MSK1) and cAMP-responsive-element-binding protein (CREB), followed by up-regulation of IL-10, was stimulated by SPG priming via activation of the spleen tyrosine kinase (Syk). Our data indicate that SPG augments the anti-inflammatory response in murine macrophages which can be useful to create an intervention for periodontal disease treatment.

Validation of a self-report questionnaire for periodontitis in a Japanese population.

We aimed to assess the validity of the self-report questionnaire for periodontitis in a Japanese population. A Japanese 9-item self-report questionnaire, developed by translating English-version questions that were used to detect periodontitis, was validated against full-mouth clinically-assessed periodontitis in 949 Japanese adults (average age = 43.2 years). Multivariable logistic regression modeling was used to calculate the area under the receiver operating characteristic curve (AUC), wherein the periodontitis case definition of the Centers for Disease Control and Prevention/American Academy of Periodontology was considered the gold standard. Severe, moderate, and mild periodontitis were identified in 6.2%, 30.0%, and 6.7% of the study population, respectively. Self-reported oral health questions combined with socio-demographic and health-related variables had an AUC > 0.70 (range, 0.71-0.87) for any periodontitis category. Four oral health questions ("have gum disease," "loose tooth," "lost bone," and "bleeding gums") were selected in the parsimonious model for severe periodontitis. The periodontitis screening score generated by the responses to these four questions had an AUC, sensitivity, and specificity of 0.82, 73.1%, and 74.3%, respectively, where the cut-off was set at 2 points. In conclusion, a locally adapted version of the self-report questionnaire had an acceptable diagnostic capacity for the detection of periodontitis in this study population.

3D spheroid culture models for chondrocytes using polyethylene glycol-coated microfabricated chip.

As chondrocytes fail to retain their chondrogenic potential in two-dimensional monolayer cultures, several three-dimensional culture systems have been employed for investigating the physiology and pathophysiology in articular cartilage tissues. In this study, we introduced a polyethylene glycol-coated microfabricated chip that enables spheroid formation from ATDC5 cell line, commonly used as a model for in vitro chondrocyte research. ATDC5 cells cultured in our devices aggregated immediately and generated a single spheroid per well within 24 h. Most cells in spheroids cultured in differentiation medium were viable and the circular shape and smooth surface of the spheroid were maintained up to 14 d in culture. We also detected potent hypoxia conditions, a key factor in chondrogenesis, in whole lesions of ATDC5 spheroids. Expression of chondrogenesis-related genes and type X collagen protein was significantly increased in ATDC5 spheroids grown in differentiation medium, compared with monolayer-cultured ATDC5 cells. We also demonstrated that the differentiation medium-induced Akt protein phosphorylation was upregulated in ATDC5 cells cultured in our spheroid device, suggesting that enhancement of chondrogenic potential in ATDC5 spheroids results from PI3/Akt signaling activation. These results indicated that our spheroid culture system could constitute a high-throughput strategy approach towards elucidating the molecular mechanisms that regulate chondrogenesis.

Associations of cytokine levels in gingival crevicular fluid of mobile teeth with clinical improvement after initial periodontal treatment.

Studies suggest that analysis of gingival crevicular fluid (GCF) is useful for evaluating periodontal status. In this study, clinical variables related to tooth mobility, and multiple cytokine levels in proximate GCF, were measured at four time points during initial periodontal treatment: before treatment (baseline), after supragingival scaling, after occlusal adjustment, and after scaling and root planing (SRP); 20 teeth from 13 patients with periodontitis were included. Baseline interleukin (IL)-10 level in GCF was significantly higher around teeth that showed substantial improvement in periodontal epithelial surface area (PESA) after SRP than around teeth without PESA improvement. IL-3 and IL-16 levels in GCF at baseline were significantly higher around teeth with a periodontal inflamed surface area (PISA) of 0 mm2 after SRP than around teeth without PISA improvement. In addition, baseline IL-7, IL-11, and IL-12p40 levels in GCF were significantly lower around teeth with decreased mobility after occlusal adjustment than around teeth without decreased mobility. These results suggest that pre-treatment cytokine levels in GCF are useful in predicting the effects of initial periodontal treatment.

A Preliminary Study on the Ability of the Trypsin-Like Peptidase Activity Assay Kit to Detect Periodontitis.

This study aimed to explore whether the Trypsin-Like Peptidase Activity Assay Kit (TLP-AA-Kit), which measures the activity of N-benzoyl-dl-arginine peptidase (trypsin-like peptidase), can be used as a reliable tool for periodontitis detection in population-based surveillance. In total, 105 individuals underwent a full-mouth periodontal examination and provided tongue swabs as specimens for further analyses. The results of the TLP-AA-Kit were scored between 1 and 5; higher scores indicated higher trypsin concentrations. Receiver operating characteristic analyses were used to evaluate the predictive validity of the TLP-AA-Kit, where the periodontitis case definition provided by the Centers for Disease Control/American Academy of Periodontology served as the reference. Severe and moderate periodontitis were identified in 4.8% and 16.2% of the study population, respectively. The TLP-AA-Kit showed high diagnostic accuracy for severe periodontitis, with an area under the curve of 0.93 (95% confidence interval = 0.88-0.99). However, the diagnostic accuracy of the TLP-AA-Kit for moderate/severe periodontitis was not reliable. While further studies are necessary to validate our results, the results provided herein highlight the potential of the TLP-AA-Kit as a useful tool for the detection of periodontitis, particularly in severe cases, for population-based surveillance.

Thymus-expressed chemokine enhances Porphyromonas gingivalis LPS-induced osteoclast formation via NFATc1 activation.

OBJECTIVE: P. gingivalis is a gram-negative anaerobic bacterium and a major periodontal pathogen. LPS produced by P. gingivalis promotes osteoclast formation. TECK is a CC chemokine whose expression is increased in gingival epithelial cells exposed to P. gingivalis LPS. In this study, we investigated the effect of TECK in osteoclastogenesis induced by P. gingivalis LPS. DESIGNS: Real time reverse transcriptase polymerase chain reaction (RTPCR) analysis and western blotting were performed to confirm TECK in MG63, human osteoblast cell line and primary murine osteoblasts and CCR9 in RAW 264.7 cells and murine bone marrow macrophages (BMMs) as osteoclast precursors. P. gingivalis LPS-treated BMMs and Raw 264.7 cells were cultured with or without TECK or TECK antibody to examine the effect of TECK on osteoclast formation. Cocultures with murine osteoblasts and bone marrow cells were also treated with or without TECK or TECK antibody. Luciferase assay and western blotting were used to determine whether TECK-CCR9 induced osteoclastogenesis was mediated through NFATc1 or NF-kB signaling. RESULTS: TECK was shown to be expressed by osteoblasts, and its receptor, CCR9, by osteoclast precursors. TECK increased P. gingivalis LPS-induced osteoclast numbers in an in vitro osteoclast formation assay using osteoclast precursors. The enhanced osteoclast formation by TECK was mediated by NFATc1, but not by NF-kB signaling. CONCLUSION: TECK may be a novel regulator of osteoclast formation induced by P. gingivalis LPS in periodontitis.

Diagnosis of Periodontal Disease from Saliva Samples Using Fourier Transform Infrared Microscopy Coupled with Partial Least Squares Discriminant Analysis.

Diagnosis of periodontal disease by Fourier transform infrared (FT-IR) microscopic technique was achieved for saliva samples. Twenty-two saliva samples, collected from 10 patients with periodontal disease and 12 normal volunteers, were pre-processed and analyzed by FT-IR microscopy. We found that the periodontal samples showed a larger raw IR spectrum than the control samples. In addition, the shape of the second derivative spectrum was clearly different between the periodontal and control samples. Furthermore, the amount of saliva content and the mixture ratio were different between the two samples. Partial least squares discriminant analysis was used for the discrimination of periodontal samples based on the second derivative spectrum. The leave-one-out cross-validation discrimination accuracy was 94.3%. Thus, these results show that periodontal disease may be diagnosed by analyzing saliva samples with FT-IR microscopy.

Periodontal conditions in an elderly Japanese population influenced by smoking status and serum immunoglobulin G2 levels.

BACKGROUND: A Japanese population residing in the same area may be suitable for evaluation of the association among IgG subclass levels, smoking status, and periodontal disease due to similar racial and environmental factors, as these factors can interact to influence serum IgG subclass levels. The present cross-sectional investigation attempted to examine the influence of serum IgG subclass levels and smoking status on periodontal condition in a population of elderly Japanese subjects. METHODS: Elderly individuals (N = 451, age, 71 years) residing in Niigata City, Japan participated in the present study. Clinical evaluations, which consisted of probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), and calculus, and serological determinations including serum IgG subclass levels and anti-Porphyromonas gingivalis fimbriae IgG subclass titers were conducted. All participants were asked to complete questionnaires regarding smoking status and were then divided into one of three groups: never smoker, former smoker, or current smoker. RESULTS: Distributions of the number of teeth did not differ significantly across the groups. The proportion of sites with CAL > or =4 mm (%CAL4) in current smokers was significantly higher in comparison with never smokers. Multiple linear regression analysis revealed that %CAL4 was influenced by number of teeth, serum IgG2 levels, gender, and smoking status (R(2) = 0.253, P < 0.001). The effect of IgG2 was greater than that of smoking status. Distribution of IgG2 was not significantly different across the three groups. CONCLUSION: These data indicate that serum IgG2 levels influences periodontal conditions in an elderly Japanese population independent of smoking status.