Levels Of Alveolar Bone Loss Research Articles

Metformin enhances the therapeutic effects of extracellular vesicles derived from human periodontal ligament stem cells on periodontitis

Metformin has shown outstanding anti-inflammatory and osteogenic abilities. Mesenchymal stem cell-derived extracellular vesicles (EVs) reveal promising therapeutic potency by carrying various biomolecules. This study explored the effects of metformin on the therapeutic potential of EVs derived from human periodontal ligament stem cells (PDLSCs) for periodontitis. PDLSCs were cultured in osteogenic medium with or without metformin, and the supernatant was then collected separately to extract EVs and metformin-treated EVs (M-EVs). After identifying the characteristics, we evaluated the anti-inflammatory and osteogenic effects of EVs and M-EVs in vivo and in vitro. Osteogenic differentiation of PDLSCs was markedly enhanced after metformin treatment, and the effect was dramatically inhibited by GW4896, an inhibitor of EVs’ secretion. Metformin significantly increased EVs’ yields and improved their effects on cell proliferation, migration, and osteogenic differentiation. Moreover, metformin significantly enhanced the osteogenic ability of EVs on inflammatory PDLSCs. Animal experiments revealed that alveolar bone resorption was dramatically reduced in the EVs and M-EVs groups when compared to the periodontitis group, while the M-EVs group showed the lowest levels of alveolar bone loss. Metformin promoted the osteogenic differentiation of PDLSCs partly through EVs pathway and significantly enhanced the secretion of PDLSCs-EVs with superior pro-osteogenic and anti-inflammatory potential, thus improving EVs’ therapeutic potential on periodontitis.

Effects of IL-34 and anti-IL-34 neutralizing mAb on alveolar bone loss in a ligature-induced model of periodontitis.

Macrophage colony-stimulating factor (M-CSF) and interleukin-34 (IL-34) are ligands for the colony-stimulating factor-1 receptor (CSF-1r) expressed on the surface of monocyte/macrophage lineage cells. The importance of coordinated signaling between M-CSF/receptor activator of the nuclear factor kappa-Β ligand (RANKL) in physiological and pathological bone remodeling and alveolar bone loss in response to oral bacterial colonization is well established. However, our knowledge about the IL-34/RANKL signaling in periodontal bone loss remains limited. Recently published cohort studies have demonstrated that the expression patterns of IL-34 are dramatically elevated in gingival crevicular fluid collected from patients with periodontitis. Therefore, the present study aims to evaluate the effects of IL-34 on osteoclastogenesis in vitro and in experimental ligature-mediated model of periodontitis using male mice. Our initial in vitro study demonstrated increased RANKL-induced osteoclastogenesis of IL-34-primed osteoclast precursors (OCPs) compared to M-CSF-primed OCPs. Using an experimental model of ligature-mediated periodontitis, we further demonstrated elevated expression of IL-34 in periodontal lesions. In contrast, M-CSF levels were dramatically reduced in these periodontal lesions. Furthermore, local injections of mouse recombinant IL-34 protein significantly elevated cathepsin K activity, increased the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts and promoted alveolar bone loss in periodontitis lesions. In contrast, anti-IL-34 neutralizing monoclonal antibody significantly reduced the level of alveolar bone loss and the number of TRAP-positive osteoclasts in periodontitis lesions. No beneficial effects of locally injected anti-M-CSF neutralizing antibody were observed in periodontal lesions. This study illustrates the role of IL-34 in promoting alveolar bone loss in periodontal lesions and proposes the potential of anti-IL34 monoclonal antibody (mAb)-based therapeutic regimens to suppress alveolar bone loss in periodontitis lesions.

Stresses Along the Root Surfaces of Maxillary Anterior Dentition During Retraction in Labial and Lingual Mechanics with Varying Level of Bone Support: A Finite Element Study

Objective The aim of this study was to evaluate and compare the stress along the root surfaces of anterior maxillary dentition during retraction in labial and lingual mechanics with varying level of bone support. Materials and methods Eight 3D finite element models (FEM) having 340,215 nodes and 211,543 elements were created with normal periodontium and different levels of alveolar bone loss; four with labial brackets and four with lingual brackets. Sliding mechanics were simulated as en masse retraction of the anterior dentition. The equivalent stresses along the roots of six anterior maxillary teeth were measured in all the models. Results Equivalent stresses in pascals (Pa) generated at the root surfaces of central incisors are always higher in labial technique (right: 4.6013 × 10−2; left: 7.1158 × 10−2) and of canines (right: 10.003 × 10−2; left: 16.789 × 10−2) are always higher in lingual technique. Conclusion In labial technique, central incisor roots are experiencing maximum stress, which might be the explanation of commonly seen higher incidence of root resorption in them during en masse retraction. In lingual technique, canine roots are experiencing higher stresses as compared to other anterior teeth during en masse retraction. Equivalent stresses generated at the root surfaces of canines are more irrespective of the alveolar bone loss in lingual technique.

Finite Element Analysis of Maxillary Anterior Dentition During Retraction With Varying Level of Bone Support

AbstractThis study is being carried out to evaluate and compare the stress along the root surfaces of anterior maxillary dentition during retraction in labial and lingual mechanics with varying level of bone support. Eight three-dimensional finite element models (FEM) were created with normal periodontium and different levels of alveolar bone loss; four with labial brackets and four with lingual brackets. Sliding mechanics were simulated as en-masse retraction of the anterior dentition. The equivalent stresses along the roots of six anterior maxillary teeth were measured in all the models. Equivalent stresses generated at the root surfaces of central incisors are always higher in labial technique and of canines are always higher in lingual technique, suggesting the increased vulnerability toward root resorption in both cases. Stresses at the root apices of all the teeth are increasing progressively when the bone loss is progressively more than 2 mm in labial technique. In labial technique, the stresses at the root apices of all the teeth are increasing progressively when the bone loss is progressively more than 2 mm. In Lingual technique, equivalent stresses generated at the root surfaces of canines are more than central and lateral incisors irrespective of the alveolar bone loss, suggesting increased susceptibility to root resorption.

The use of probiotics can reduce the severity of experimental periodontitis in rats with metabolic syndrome: An immunoenzymatic and microtomographic study.

This study evaluated the effects of Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019) in the development of periodontitis (PE), associated or not with metabolic syndrome, (MS) in rats. Ninety-six rats were grouped according to a food protocol: high-fat diet for induction of MS or standard diet for the control groups (C). They were subdivided into groups with (+) and without (-) PE, receiving (*) or not (**) probiotic (PROB): C-**, CP-*, PE+**, PEP+*, MS- MSP-*, MSPE+**, and MSPEP+*. PROB administration started on the eighth week of the study and PE was induced on the 14th week by placing ligature on the animals' lower first molars. Euthanasia occurred in the 16th week. Biomolecular analyzes, immunoenzymatic assays, and microtomographic analyses were performed. The data obtained were analyzed statistically (P<0.05). The PEP and MSPEP groups showed lower levels of alveolar bone loss when compared with the PE and MSPE groups, respectively (P<0.05). The immunoenzymatic analysis showed higher levels of interleukin (IL)-1β and a higher receptor activator of NF-kappaB ligand (RANKL)/osteoprotegerin (OPG) ratio in the MSPE group when compared with the MSPEP group (P<0.05). The PEP group showed lower levels of tumor necrosis factor (TNF)-α and IL-6 when compared with the PE group. The use of PROB attenuated dyslipidemia parameters in animals with MS, with or without PE. B. lactis HN019 reduced more significantly the severity of PE in rats with MS, modulating both systemic metabolic and immunoinflammatory parameters in periodontal tissues.

Effects of Limosilactobacillus fermentum CCFM1139 on experimental periodontitis in rats.

Periodontitis is a polymicrobial inflammatory disease often characterized by the excessive colonization of Porphyromonas gingivalis and Fusobacterium nucleatum, which causes alveolar bone resorption and advanced oral inflammation. This study aimed to evaluate the effect of Limosilactobacillus fermentum CCFM1139 on experimental periodontitis induced following ligature and infection with P. gingivalis and F. nucleatum in vivo. The results showed that L. fermentum CCFM1139 significantly reduced weight loss associated with periodontal inflammation (p < 0.05), while decreasing both the P. gingivalis and F. nucleatum populations within the oral cavity of rats (p < 0.05) and regulating the expression of tumor necrosis factor-alpha, interleukin (IL)-1 beta, and IL-8 in the periodontal tissue (p < 0.05). Microcomputed tomography (micro-CT) and histopathological examination revealed that L. fermentum CCFM1139 supplementation reduced the level of alveolar bone loss and bone porosity and increased bone volume (p < 0.05) in the experimental animals. Furthermore, L. fermentum CCFM1139 exhibited promising effects in preventing the deepening of the periodontal pocket and the increase in the gap between adjacent molars. Thus L. fermentum CCFM1139 was shown to have solid potential as an oral probiotic for protection against periodontitis suggesting that this may be a good candidate in the production of a new functional food for improving periodontitis.

Impaired salivary SIgA antibodies elicit oral dysbiosis and subsequent induction of alveolar bone loss.

Secreted IgA (SIgA) plays a central role in preventing bacterial and viral infections on mucosal surfaces by neutralizing toxins and viruses and inhibiting bacterial attachment to epithelial cells. However, the role of salivary SIgA antibodies (Abs) in regulating oral flora is still unknown. This study aimed to evaluate the association among oral bacteria, their metabolites and periodontitis in IgA-deficient (IgA KO) and wild-type (WT) control mice. Microcomputed tomography (micro-CT) analysis was used to assess alveolar bone resorption as a development of periodontitis. The bacterial profiles of saliva were determined using the next-generation sequencing assays. Furthermore, the metabolites in saliva were measured and compared using CE-TOFMS. Salivary microbiota of IgA KO mice revealed a remarkably decreased frequency of Streptococcus, and increased percentages of Aggregatibacer, Actinobacillus, and Prevotella at the genus level when compared with those of WT. Compared to WT control mice of the same age, the level of alveolar bone loss was significantly increased in IgA KO mice, and infiltration of osteoclasts was found on the surface of the alveolar bone. The metabolome profile indicated that the metabolites of IgA KO mice had greater variability in carbon metabolic, urea cycle, and lipid pathways than WT mice. These results suggest that salivary SIgA plays an important role in regulating and maintaining normal oral microflora to prevent the development of periodontal disease.

Periodontal status and bone metabolism in women in reproductive and postmenopausal periods.

Objectives Chronic periodontitis is one of the most common diseases in the world. Periodontitis occurs more frequently in postmenopausal women due to hormonal changes and in patients with osteoporosis. Thus, the aim of our study was to compare levels of alveolar bone loss of mandible and maxilla and bone tissue remodeling markers in women of reproductive and postmenopausal periods. Methods Fifty-nine women aged 25-68 years were enrolled in a cross-sectional study and divided into two groups. Group I consisted of 42 women of reproductive age and Group II included 17 women in their postmenopausal period. The level of alveolar bone loss of mandible and maxilla was assessed using dental panoramic radiography, and the level of bone remodeling markers (Beta C-terminal telopeptide of type I collagen [β-CTx] and osteocalcin) was obtained in both groups. Results Women in the postmenopausal period have higher level of alveolar bone loss in mandible and maxilla than women of reproductive age. The level of ß-CTx and osteocalcin was significantly higher in Group II, compared to Group I (p=0.002 and p=0.005, respectively). Conclusions In postmenopausal women, on the background of significantly higher bone remodeling, an increase of alveolar bone loss of mandible and maxilla was observed.

Temporal and dynamic changes in gingival blood flow during progression of ligature-induced periodontitis.

To evaluate temporal changes in gingival blood flow (GBF) during progression of periodontitis in rats using alaser Doppler flowmeter (LDF) approach and to characterize morphological and biochemical features inthe periodontium associated with GBF. Forty-two Wistar rats were divided into aligature-induced periodontitis group and acontrol group. To induce periodontitis, ligatures were tied around maxillary first molars bilaterally. GBF was measured in palatal gingiva at pretreatment and following ligature placement after 30min, 1, 3, 7, 14, 21, and 28days using LDFwith a non-contact probe. Bone loss and gene expression in gingival tissues were assessed using micro-computed tomography (μCT) and quantitative polymerase chain reaction (PCR), respectively. Immunostaining for vascular endothelial growth factor (VEGF) in themaxilla was also histologically evaluated. GBF in the ligature group increased significantly compared with the control group 30min after ligation. However, on days 3 and 7, GBF decreased in the ligature group. Also, after day 10, there was no difference in GBF between groups. The levels of alveolar bone loss, gene expression (interleukin-6, cluster of differentiation-31, VEGF-A, and lymphatic vessel endothelial hyaluronan receptor-1), and immunostained VEGF-positive vessels correlated well with changes in GBF. CONCLUSIONPROGRESSION OF PERIODONTITIS: In rats was associated with atriphasic pattern of GBF, consisting of ashort initial increase, followed by arapid decrease, and then agradual plateau phase.

Diagnosing periodontal and dental indicators with horizontal and vertical bitewing radiographs.

The aim of this study is to compare information provided by the 2 orientations of bitewing radiographs, horizontal (HBW) and vertical (VBW) taken in a dental school. Radiographic records were reviewed at Tufts University School of Dental Medicine (TUSDM) for patients showing posterior bone loss who had both HBW and VBW. 320 records were reviewed with 6 criteria: visibility of crestal bone from the distal of the cuspids to the distal of the most posterior tooth, visibility of horizontal or angular bone loss, the crestal density of bone, visibility of interproximal contact areas, visibility of the entire anatomical crown, and visibility of furcations. Significantly higher number of VBW compared with HBW (P<0.0001) showed the levels of alveolar bone loss (52.81% vs. 3.75%), the type of loss (angular or horizontal) (50.94% vs. 3.75%), the crestal bone density (28.75% vs. 0.63%), the contact areas (20.63% vs. 14.38%), and the furcations (43.44% vs. 1.25%). A greater number of HBW showed the entire anatomical crown compared with VBW. No significant difference was detected in the number of radiographs taken per HBW and VBW set. For patients with alveolar bone loss, VBW are superior to HBW when assessing bone levels, density, morphology, tooth furcations, and evaluating interproximal contact areas for caries. It is recommended that the vertical bitewing technique be taught as a standard in dental, dental hygiene, and dental assisting schools for adult patients showing evidence of posterior interdental bone loss.

Catechin ameliorates Porphyromonas gingivalis-induced inflammation via the regulation of TLR2/4 and inflammasome signaling.

Porphyromonas gingivalis is a major periodontopathogen found in patients with chronic periodontitis that can lead to alveolar bone or tooth loss. Interleukin-1β (IL-1β), a proinflammatory cytokine, is most relevant to the pathogenesis of periodontitis. Catechin is one of the main polyphenol compounds found in green tea and possesses a range of health benefits. This study examined the anti-inflammatory effects of catechin in THP-1-derived macrophages infected with P. gingivalis as well as its effects on P. gingivalis-induced periodontitis in a mouse model. The cytokine levels and relevant protein expression in THP-1 cells were measured using an enzyme-linked immunosorbent assay and Western blot analysis, respectively. An apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) pyroptosome formation was measured by confocal laser scanning microscopy. Micro-computed tomography was used to determine the level of bone loss induced by a P. gingivalis oral infection. Catechin attenuated the production of IL-1β by inhibiting pro-IL-1β expression via the downregulation of nuclear factor-κB, p38 mitogen-activated protein kinase, and Toll-like receptor signaling. In addition, catechin inhibited the activation of inflammasomes induced by P. gingivalis, but did not affect the growth of P. gingivalis. Catechin reduced the level of alveolar bone loss in a P. gingivalis-induced periodontitis mouse model. Catechin possesses anti-inflammatory properties by reducing the level of IL-1β production, suggesting that it can potentially be used for the prevention and treatment of periodontal inflammation caused by P. gingivalis.

The effects of morus nigra on the alveolar bone loss in experimentally-induced periodontitis.

The aim of this study is to evalute the anti-inflammatory effects of morus migra on experimentally-induced periodontitis in rats. Twenty-four Wistar-albino rats were randomly divided into three groups: control group (C, n=8), experimental periodontitis (PER, n=8), experimental periodontitis and treated with Morus nigra (MN+PER, n=8) (50 mg/kg per day for 21 days). After 21 days, the rats were sacrificed, and alveolar bones were evaluated histopathologically and histometrically analyzed to obtain level of alveolar bone loss. The detection of RANKL and OPG were immunohistochemically performed. Serum and tissue levels of MMP-8 and MMP-13 were also analyzed. Morus nigra treatment decreased tissue MMP-8 and MMP-13 levels and there were significant differences in the case of tissue levels of MMP-8 and MMP-13 between groups PER and MN+PER (p=0.035, p=0.041). There were no significant differences among all the groups serum levels of MMP-8 and MMP-13 (p=0.067, p=0.082). In the histometric evaluation, alveolar bone loss was greater in the PER group compared to C and MN groups (p=0.035). Immuno-histochemical staining of RANKL activities were found significantly lower (p=0.037) and OPG activities were found significantly higher in MN+PER group when compared to PER group (p=0.021). The present study reveals that systemic administration of Morus nigra significantly inhibited the regional alveolar bone resorption and contributes to periodontal healing in the rat experimental-periodontitis models.

Impact of systemic diseases and tooth-based factors on outcome of root canal treatment.

To investigate the impact of systemic health and tooth-based factors on the outcome of root canal treatment (RCT). The target population consisted of all patients receiving RCT at the Helsinki University Clinic in 2008-2011. The inclusion criteria were diagnosable pre- and postoperative (minimum 6months after root filling) radiographs and adequate patient records of RCT available. Teeth extracted for nonendodontic reasons were excluded. Patient documents including digital radiographs of 640 permanent teeth in 504 patients were scrutinized. The radiographs were assessed by two examiners under standardized conditions. The Periapical Index was used to define radiographically 'healthy' and 'healing' cases as successful. Data included systemic health, technical quality of root fillings, type of restoration and level of alveolar bone loss. Statistical evaluation of differences between groups included chi-squared tests and Fisher's exact tests. Logistic regression modelling utilizing robust standard errors to allow for clustering within patients was applied to analyse factors related to the outcome of RCT. The mean age of patients was 51.5years (standard deviation (SD) 15.0; range 10-83), and 49% were female. In 41 cases (6%), the patient had diabetes mellitus (DM), in 132 (21%) cardiovascular disease and in 284 (44%) no systemic disease. The follow-up period was 6-71months (mean 22.7). In the primary analyses, the success rate of RCT was 73.2% in DM patients and 85.6% in patients with no systemic disease (P=0.043); other systemic diseases had no impact on success. In the multifactorial analysis, the impact of DM became nonsignificant and RCTs were more likely to succeed in the absence of apical periodontitis (AP; odds ratio (OR)=4.4; P<0.001), in teeth with optimal root filling quality (OR=2.5; P<0.001), in teeth restored with indirect restorations (OR=3.7; P=0.002) and in teeth with none/mild alveolar bone loss (OR=2.4; P=0.003). DM diminished the success of RCT, especially in teeth with apical periodontitis. However, tooth-based factors had a more profound impact on the outcome of RCT. This should be considered in clinical decision-making and in assessment of RCT prognosis.

EVALUATION OF USING MINERALIZED PLASMATIC MATRIX IN OSSEOUS REGENERATION

INTRODUCTION: Diabetes Mellitus (DM) is a systemic disease that affects large part of the population and is considered a relative contraindication to implant therapy. However, there are studies showing that the survival rate of implants in type-2 diabetic patients is approximately 90%, approaching that of non-diabetic patients. It is also shown that these results are strictly correlated with the importance of glycemic control to provide predictability of success rates and improve osseointegration of the implants inserted. There is no evidence whether controlled type-1 diabetes is or is not a risk factor for implant failure. OBJECTIVES: The objective of this study was to clinically and radiographically evaluate the success of implant overdenture in controlled type-1 diabetic patients. MATERIALS AND METHODS: Ten completely edentulous well controlled type-1 and ten non-diabetic patients were selected and divided into group I and II respectively. All patients received three implant assisted mandibular overdentures through minimally invasive flapless technique. Clinical evaluation of implant stability was performed using Osstell ISQ immediately after implant placement (base line), four months and one year after prosthesis insertion. Level of alveolar bone loss around each abutment was also evaluated using Cone Beam Computed Tomography (CBCT) at the time of final prosthesis insertion (base line), four months and one year after insertion. RESULTS: Of the ten patients in the study group, two patients were lost yielding a success rate of 80 % in group I. Clinical results of implant stability test showed significant decrease in stability in the study group as compared to the control group, also radiographical results revealed significant increase in amount of average crestal bone loss in the diabetic patients. CONCLUSIONS: Within the limitations of this study, and based on the clinical level, the implant overdenture may be recognized as being predictable treatment option for controlled type-1 diabetic patients.

25-Hydroxyvitamin D3 -enhanced PTPN2 positively regulates periodontal inflammation through the JAK/STAT pathway in human oral keratinocytes and a mouse model of type 2 diabetes mellitus.

Periodontitis is an increasingly prevalent complication of diabetes mellitus (known as diabetes mellitus-associated periodontitis), and 25-hydroxyvitamin D3 (25VD3 ) was recently found to be a critical regulator of innate immunity in this disease, but the underlying mechanisms remain poorly understood. T-cell protein tyrosine phosphatase non-receptor type 2 (PTPN2) is a potential downstream protein of the 25VD3 /vitamin D receptor pathway. The aim of this study was to investigate the regulation of PTPN2 in periodontal inflammation in diabetes mellitus-associated periodontitis. Porphyromonas gingivalis-infected db/db mice were treated with 25VD3 . Their fasting blood glucose and body weight were monitored every other week, and the levels of alveolar bone loss and serum inflammatory cytokines (tumor necrosis factor-α, interferon-γ and interleukin-6) were determined at the time of killing. The effect of PTPN2 on human OKF6-TERT2 oral keratinocytes was examined through the knockout of PTPN2 using the CRISPR/Cas9 knockout plasmid. The expression levels of the PTPN2, vitamin D receptor and JAK1/STAT3 signaling proteins in the gingival epithelium and OKF6-TERT2 cells were determined through western blot and immunohistochemical analyses. After 25VD3 treatment, db/db mice exhibited alleviated serum inflammatory cytokines and alveolar bone loss, and 25VD3 -enhanced PTPN2 expression decreased the expression of the JAK1/STAT3 signaling proteins in the gingival epithelium. Analyses of human oral keratinocytes showed that 25VD3 increased the expression of PTPN2, which dephosphorylates protein substrates in the JAK1/STAT3 signaling pathway. PTPN2 contributed to a decrease in periodontal inflammation in type 2 diabetes mellitus via dephosphorylate protein substrates in the JAK1/STAT3 signaling pathway after 25VD3 treatment in human oral keratinocytes and a mouse model of type 2 diabetes mellitus. A thorough understanding of PTPN2 and its involvement in inhibiting inflammation might provide alternative therapeutic approaches for the pathogenesis and treatment of diabetes mellitus-associated periodontitis.

Patients with Chronic Obstructive Pulmonary Disease Suffer from Worse Periodontal Health-Evidence from a Meta-Analysis.

Background and Objective: It is widely accepted that there is an association between chronic obstructive pulmonary disease (COPD) and periodontitis. However, whether the periodontal status of the COPD patients is worse than that of the non-COPD subjects is seldom assessed. The findings currently available are inconsistent, some even contradictory. Therefore, we performed this meta-analysis to compare the periodontal health status of COPD patients and non-COPD subjects.Methods: PubMed and Embase were searched for all of the eligible studies which comparing the periodontal status between COPD patients and non-COPD subjects. The results of periodontal parameters in each study were extracted and the mean differences and 95% confidence intervals (CIs) for each parameter were calculated to determine their overall effects.Results: In total, 14 studies involving 3348 COPD patients and 20612 non-COPD controls were included and 9 periodontal indexes were analyzed. The mean differences (95% CIs) between COPD and non-COPD subjects for probing depth, clinical attachment loss, level of alveolar bone loss, plaque index, oral hygiene index, bleeding index, bleeding on probing, gingival index, and remaining teeth were 0.261 (0.020–0.501), 0.480 (0.280–0.681), 0.127 (0.000–0.254), 0.226 (0.043–0.408), 0.802 (0.326–1.279), 0.241 (−0.106 to 0.588), 6.878 (5.489–8.266), 0.364 (0.036–0.692), and −3.726 (−5.120 to −2.331), respectively.Conclusion: In summary, this meta-analysis demonstrates that the COPD patients suffer from worse periodontal health status, indicated by deeper periodontal pockets, high level of clinical attachment loss, worse oral hygiene, more inflammation and bleeding in the gingival tissue, and lower number of remaining teeth. Nevertheless, considering the limitations in our meta-analysis, more high-quality, and well-designed studies focusing on the periodontal health of the COPD patients are required to validate our conclusion.

Influence of experimental periodontitis on cardiac oxidative stress in rats: a biochemical and histomorphometric study.

The role of oxidative stress in the process of cardiac remodeling, hypertrophy and heart failure is a current topic. The purpose of this experimental study was to investigate the influences of periodontitis on levels of cardiac oxidative stress. Twenty rats were separated into two groups: control and experimental periodontitis (EP). Periodontitis was induced by placing a 3.0 silk suture in the cervix of the left and right mandibular first molar teeth for 5 wk. At the end of the experiment, the animals were killed and blood samples and mandibular and ventricular cardiac tissue samples were collected. Levels of alveolar bone loss were determined using measurements performed on histological slices and radiographies. Left ventricular tissue 8-hydroxy-2'-deoxyguanosine, malonylaldehyde, glutathione peroxidase, total oxidant status, total antioxidant status (TAS) levels and serum paraoxonase-1 activity were evaluated biochemically. Measurements performed on the histological slices and radiographies demonstrated that applying the ligature caused obvious alveolar bone loss. Oxidative damage markers (malonylaldehyde, 8-hydroxy-2'-deoxyguanosine, oxidative stress index: total oxidant status/TAS) were significantly higher, and antioxidant markers (glutathione peroxidase, TAS) were statistically insignificantly higher, in the hearts of rats with EP when compared to the controls. In addition, reduced serum paraoxonase-1 activity was also detected in the EP group. The pronounced increase in cardiac oxidative stress caused by periodontitis was due to an excessive increase in the production of reactive oxygen species, rather than due to decreased antioxidant capacity. The results indicate that periodontitis-related cardiac oxidative stress might be one of the mechanisms that contribute to the pathological process that leads to heart failure.

A novel method of sampling gingival crevicular fluid from a mouse model of periodontitis

Using a mouse model of silk ligature-induced periodontal disease (PD), we report a novel method of sampling mouse gingival crevicular fluid (GCF) to evaluate the time-dependent secretion patterns of bone resorption-related cytokines. GCF is a serum transudate containing host-derived biomarkers which can represent cellular response in the periodontium. As such, human clinical evaluations of PD status rely on sampling this critical secretion. At the same time, a method of sampling GCF from mice is absent, hindering the translational value of mouse models of PD. Therefore, we herein report a novel method of sampling GCF from a mouse model of periodontitis, involving a series of easy steps. First, the original ligature used for induction of PD was removed, and a fresh ligature for sampling GCF was placed in the gingival crevice for 10min. Immediately afterwards, the volume of GCF collected in the sampling ligature was measured using a high precision weighing balance. The sampling ligature containing GCF was then immersed in a solution of PBS-Tween 20 and subjected to ELISA. This enabled us to monitor the volume of GCF and detect time-dependent changes in the expression of such cytokines as IL-1b, TNF-α, IL-6, RANKL, and OPG associated with the levels of alveolar bone loss, as reflected in GCF collected from a mouse model of PD. Therefore, this novel GCF sampling method can be used to measure various cytokines in GCF relative to the dynamic changes in periodontal bone loss induced in a mouse model of PD.

Influences of Fucoxanthin on Alveolar Bone Resorption in Induced Periodontitis in Rat Molars.

The aim of this study was to evaluate the effects of systemic fucoxanthin treatment on alveolar bone resorption in rats with periodontitis. Thirty rats were divided into control, experimental periodontitis (EP), and experimental periodontitis-fucoxanthin (EP-FUCO) groups. Periodontitis was induced by ligature for four weeks. After removal of the ligature, the rats in the EP-FUCO group were treated with a single dose of fucoxanthin (200 mg/kg bw) per day for 28 consecutive days. At the end of the study, all of the rats were euthanized and intracardiac blood and mandible tissue samples were obtained for biochemical, immunohistochemical, and histometric analyses. Fucoxanthin treatment resulted in a slight decrease in tumor necrosis factor-α, interleukin-1β, and interleukin-6 levels and a significant decrease in oxidative stress index. It was observed that fucoxanthin caused a significant reduction in receptor activator of nuclear factor kappa-β ligand (RANKL) levels and a statistically non-significant elevation in osteoprotegerin and bone-alkaline phosphatase levels. There were no significant differences in alveolar bone loss levels between the EP and EP-FUCO groups. This experimental study revealed that fucoxanthin provides a limited reduction in alveolar bone resorption in rats with periodontitis. One of the mechanisms underlying the mentioned limited effect might be related to the ability of fucoxanthin to inhibit oxidative stress-related RANKL-mediated osteoclastogenesis.

Evaluation of the Stress Induced in Tooth, Periodontal Ligament & Alveolar Bone with Varying Degrees of Bone Loss During Various Types of Orthodontic Tooth Movements.

The force applied on to a tooth with periodontal bone loss may generate different magnitude and pattern of stresses in the periodontium when compared to a tooth with no bone loss & under the same force system. The intensity of the forces and moment to force ratios needed to be applied during an Orthodontic treatment must be adapted to obtain the same movement as in a tooth with a healthy periodontal support. Evaluation and assessment of the stress distribution during various types of Orthodontic tooth movement on application of Orthodontic force, at various levels of alveolar bone loss; & determination of the most ideal force system producing the Optimum Stress (i.e., stress within optimum range), uniformly (conducive to bodily movement of maxillary canine with varying degrees of bone loss). A human maxillary canine tooth of right side was simulated by means of Finite Element Method (FEM). Five different models were constructed with bone loss ranging from 0mm in model 1, to 8mm in model 5 (progressing at 2mm per model). Ten different loading conditions were applied on these models and the stress generated was charted at various occluso-gingival levels and surfaces around the tooth. The evaluation and assessment of the stress distribution during various types of Orthodontic tooth movement on application of Orthodontic force, at various levels of alveolar bone loss was done. The results showed that there was a high positive correlation between the increase in bone loss & the stress generated, suggesting an elevation in the stress with advancing bone loss. Additionally, the type of tooth movement was found to be changed with bone loss. During the determination of ideal force system it was found that the centre of resistance of the canine migrated apically with bone loss and an increase in the moment to force ratio (Mc:F) was required to control the root position in these cases. A high positive correlation exists between the increase in bone loss and the stress generated. Suitable modification should be done in the force system under bone loss conditions.