Influence of Adjacent Teeth Absence or Extraction on the Outcome of Non-Surgical Periodontal Therapy.

Background: Extraction of periodontally compromised or strategically non-important teeth is often an integral part of non-surgical periodontal treatment (NSPT). This study evaluated the association between the status of adjacent teeth and the outcome of NSPT on molars. Methods: Charting data of patients with generalized chronic periodontitis receiving NSPT in 2012-2014 were included. The association between initial clinical parameters and significant clinical improvement, including the reductions of probing pocket depth (PPD) and clinical attachment loss (CAL), in molar teeth with severe periodontitis after NSPT was assessed by a generalized linear model and logistic regression. Results: ≥7 mm PPD and <2 mm gingival recession (REC) at the tooth level, and ≥7 mm PPD, ≥7 mm CAL and <2 mm REC at the site level, were associated with significant clinical improvement. Absence or extraction of an adjacent tooth achieved an additional 0.22-0.23 mm and 0.60-0.83 mm clinical improvement. Among the interproximal sites, ≥7 mm PPD, <2 mm REC, ≥7 mm CAL,

Association of initial mucogingival status with clinical outcome of non-surgical periodontal therapy: A retrospective analysis of 204 patients.

BACKGROUND/PURPOSE: This study was conducted to evaluate the influence of mucogingival parameters, including keratinized mucosa (KM) and attached gingiva (AG), on the outcome of non-surgical periodontal therapy (NSPT). METHODS: A total of 204 non-smoking patients with generalized chronic periodontitis who received NSPT between 2012 and 2014 were included. The Mantel-Haenszel chi-square test was used to assess the associations between initial mucogingival parameters and initial clinical parameters on the buccal aspect, and the associations between initial mucogingival parameters and outcome clinical parameters on the buccal aspect of the sites with severe periodontal destruction. The generalized liner model was used to evaluate the contribution of initial clinical parameters to the outcome of NSPT. RESULTS: KM ≥ 3 mm was associated with greater probing pocket depth (PD), less gingival recession (REC), and less clinical attachment level (CAL), and AG < 1 mm was associated with greater PD, REC, and CAL before NSPT. At the sites with severe periodontal destruction, KM ≥ 3 mm was associated with greater PD reduction (0.25 ± 0.08 mm) and CAL gain (0.25 ± 0.09 mm), and AG < 1 mm was associated with greater CAL gain (0.15 ± 0.08 mm) after NSPT. Initial PD ≥ 7 mm and non-molar teeth showed greater contribution to the outcome of NSPT. CONCLUSION: Less AG (<1 mm) was associated with greater periodontal destruction at baseline. At the sites with severe periodontal destruction, greater KM (≥3 mm) and less AG (<1 mm) resulted in better outcomes of NSPT.

Sphingosine-1-phosphate stimulated connective tissue growth factor expression in human buccal fibroblasts: Inhibition by epigallocatechin-3-gallate.

BACKGROUND/PURPOSE: Connective tissue growth factor (CCN2) has been associated with the pathogenesis of various fibrotic diseases, including oral submucous fibrosis (OSF). The chemical constituents of areca nut along with the mechanical trauma cause OSF. The coarse fibers of areca nut injure the mucosa and hence sphingosine-1-phosphate (S1P) is released at the wounded sites. Recent studies have shown that S1P is involved in wound healing and the development of fibrosis. The aims of this study were to investigate the effects of S1P on CCN2 expression in human buccal fibroblasts (HBFs) and identify the potential targets for drug intervention or chemoprevention of OSF. METHODS: Western blot analyses were used to study the effects of S1P on CCN2 expression and its signaling pathways in HBFs and whether epigallocatechin-3-gallate (EGCG), the main and most significant polyphenol in green tea, could inhibit this pathway. RESULTS: S1P significantly enhanced CCN2 synthesis in HBFs. This effect can be inhibited by c-Jun NH2-terminal kinase (JNK) inhibitor and extracellular signal-regulated kinase inhibitor but not by P38 mitogen-activated protein kinase inhibitor. Interestingly, EGCG completely blocked S1P-induced CCN2 expression via suppressing S1P-induced JNK phosphorylation. CONCLUSION: S1P released by repetitive mechanical trauma during AN chewing may contribute to the pathogenesis of OSF through upregulating CCN2 expression in HBFs. EGCG could be an adjuvant to the current offered therapy options or the prevention of OSF through suppression of JNK activation.

Association of pocket epithelial cell proliferation in periodontitis with TLR9 expression and inflammatory response.

BACKGROUND/PURPOSE: Inflammatory response is triggered after recognition of microbial ligands by innate receptors such as Toll-like receptors (TLRs) and Nucleotide oligomerization domain (NOD)-like receptors (NLRs). In this study, we examined serial frozen sections of gingival biopsies from patients with gingivitis or periodontitis by immunohistochemical analysis for the topographic expression patterns of selected innate receptors and their association with cell proliferation in clinically healthy and diseased gingival tissues. METHODS: A total of 19 gingival biopsies were collected from patients at the School of Dentistry, National Taiwan University Medical Center according to approved protocol and with informed consent. The specimens were assigned to either the gingivitis group or periodontitis group after clinical evaluation using gingival index. Frozen sections of gingival biopsies were stained with hematoxylin and eosin for histological evaluation. Serial sections of the same samples were stained with a panel of antibodies for immunohistochemical analysis. Expression of each protein marker was compared in the oral versus the sulcular epithelium of the same section. RESULTS: Expression of cytokeratin 19 (CK19) was markedly increased in the basement membranes of the oral epithelium and in all layers of the pocket epithelium where it caused evident cell proliferation and migration of sulcular epithelial cells into the lamina propria of periodontitis tissue. TLR4 and the cytoplasmic NLRP3 were expressed in all sections examined regardless of disease state. However, expression of TLR9-, CK19- and collagenolytic matrix metalloproteinase-13 and activated NF-κB subunit p65 was more commonly found in periodontitis tissues than in gingivitis tissues. CONCLUSION: Activation of TLR9 signaling in the pocket epithelium was highly associated with periodontal inflammation and possibly with loss of tissue integrity. Further studies of mechanisms by which TLR9 signaling is activated in the periodontal epithelium may lead to new strategies for treating periodontitis.

Epigallocatechin-3-gallate inhibits lysophosphatidic acid-stimulated connective tissue growth factor via JNK and Smad3 suppression in human gingival fibroblasts.

BACKGROUND/PURPOSE: Connective tissue growth factor (CTGF/CCN2) is involved in the development and progression of fibrotic diseases, including gingival overgrowth (GO). Recent studies indicate that lysophosphatidic acid (LPA) is also significantly involved in wound healing and the development of fibrosis. This study investigated whether epigallocatechin-3-gallate (EGCG) can inhibit LPA-induced CCN2 expression in human gingival fibroblast (GF) and its mechanism. METHODS: Western blot analyses were used to study the signaling pathways of LPA-induced CCN2 expression in human GFs and the effects of EGCG on this pathway. RESULTS: LPA stimulated CCN2 synthesis in human GFs. This effect can be significantly inhibited bytransforming growth factor-ß type I receptor/ALK5, Smad3, and JNK inhibitors but not ERK, P38, and MAPK inhibitors. EGCG completely inhibited LPA-induced CCN2 expression through attenuating the LPA-induced JNK and Smad3 phosphorylation in human GFs. CONCLUSION: LPA produced at the surgical wound may contribute to the recurrence of GO by upregulating CCN2 expression in human GFs. This effect was mediated by Smad3 and JNK activation and ALK5 transactivation. EGCG could be a useful agent for reducing the recurrence of GO after surgery through suppression of JNK and Smad3 activations.

Epigallocatechin-3-gallate blocks triethylene glycol dimethacrylate-induced cyclooxygenase-2 expression by suppressing extracellular signal-regulated kinase in human dental pulp and embryonic palatal mesenchymal cells.

INTRODUCTION: Methacrylate resin-based materials could release components into adjacent environment even after polymerization. The major components leached include triethylene glycol dimethacrylate (TEGDMA). TEGDMA has been shown to induce the expression of cyclooxygenase-2 (COX-2). However, the mechanisms are not completely understood. The aims of this study were to investigate the molecular mechanism underlying TEGDMA-induced COX-2 in 2 oral cell types, the primary culture of human dental pulp (HDP) cells and the human embryonic palatal mesenchymal (HEPM) pre-osteoblasts, and to propose potential strategy to prevent or ameliorate the TEGDMA-induced inflammation in oral tissues. METHODS: TEGDMA-induced COX-2 expression and its signaling pathways were assessed by Western blot analyses in HDP and HEPM cells. The inhibition of TEGDMA-induced COX-2 protein expression using various dietary phytochemicals was investigated. RESULTS: COX-2 protein expression was increased after exposure to TEGDMA at concentrations as low as 5 µmol/L. TEGDMA-induced COX-2 expression was associated with reaction oxygen species, the extracellular signal-regulated kinase 1/2, and the p38 mitogen-activated protein kinase signaling pathways in HDP and HEPM cells. The activation of p38 mitogen-activated protein kinase was directly associated with reactive oxygen species. Epigallocatechin-3-gallate suppressed TEGDMA-induced COX-2 expression by inhibiting phosphorylation of extracellular signal-regulated kinase 1/2. CONCLUSIONS: Cells exposed to low concentrations of TEGDMA may induce inflammatory responses of the adjacent tissues, and this should be taken into consideration during common dental practice. Green tea, which has a long history of safe beverage consumption, may be a useful agent for the prevention or treatment of TEGDMA-induced inflammation in oral tissues.

5-aminolevulinic acid induce apoptosis via NF-κB/JNK pathway in human oral cancer Ca9-22 cells.

BACKGROUND: 5-aminolevulinic acid-based photodynamic therapy (5-ALA-PDT) is being used to treat oral pre-cancerous and cancerous lesions with some encouraging clinical outcomes. However, the exact mechanisms behind the photodynamic treatment are still not fully elucidated. METHOD: Flow cytometry, TdT-mediated dUTP nick end labeling assay and Western blot analysis were used to investigate the effects of 5-ALA-PDT on human oral cancer Ca9-22 cells. RESULTS: We found that 5-ALA-PDT induces apoptosis in Ca9-22 cells. Western blotting showed that 5-ALA-PDT activates both the caspase-8 and caspase-9 pathways, which differed from previous studies conducted in other cell types. Activation of JNK was evident as early as 30 min. The caspases activation was inhibited by JNK inhibitor SP600125. Treatment with NF-κB inhibitor Bay 11-7082 (Bay) completely abrogated ALA-PDT-induced JNK activation. In addition, Bay and SP600125 almost completely abolished ALA-PDT-induced apoptosis. CONCLUSION: These results demonstrate significant involvement of caspase-8 and -9 and their upstream NF-κB-JNK pathways in ALA-PDT-induced apoptosis. Future studies on how NF-κB and JNK activity regulate ALA-PDT response should provide a better strategy for the treatment of oral cancer.

Expression of Cyr61 (CCN1) in human oral squamous cell carcinoma: An independent marker for poor prognosis.

BACKGROUND: Cysteine-rich 61 (Cyr61 [CCN1]) has disparate functions in tumorigenesis that are dependent on the cell types. The aim of the study was to investigate its role in the growth of oral squamous cell carcinoma (SCC). METHODS: The study used immunohistochemistry to examine Cyr61 expression in 93 oral SCC specimens and assessed the effect of Cyr61 overexpression on proliferation and migration of oral SCC cells in vitro and xenograft growth in severe combined immunodeficient (SCID) mice. RESULTS: High expression of Cyr61 significantly correlated with large tumor size (p = .009) and advanced tumor stage (p = .036). Multivariate analysis revealed that high Cyr61 (relative risk [RR] 2.44, 95% confidence interval [CI] 1.209-4.95, p = .010) significantly correlated with mortality. Forced expression of Cyr61 stimulated the motility and growth of Ca9-22 cells in vitro and enhanced xenograft growth in SCID mice. CONCLUSIONS: Cyr61 is a positive growth modulator of oral SCC and Cyr61 overexpression is an independent prognostic indicator for patients with oral SCC.

Polymer-assisted regeneration therapy with Atrisorb barriers in human periodontal intrabony defects.

AIM: This study compared clinical results of 40 periodontal osseous defects treated by two types of absorbable barrier materials. MATERIAL AND METHODS: Thirty patients (23 males and seven females) suffering from moderate to advanced periodontitis (with comparable osseous defects) were randomly assigned to receive either Atrisorb barrier (n = 22; group A) or Resolut XT barrier (n = 18; group B) therapy. Periodontal phase I treatment and oral hygiene instruction were performed before periodontal surgery. Papillary preservation, partial thickness flap, citric acid root conditioning, and decortication procedures were applied during the operation. Bone defects were filled with demineralized freeze-dried bone allograft and minocycline mixture (4:1 ratio). Postoperative care included 0.10% chlorhexidine rinse daily and antibiotic medication for 2 weeks. Clinical assessments including probing depth (PD), clinical attachment level (CAL), gingival recession (GR), plaque index (PII), gingival index (GI), and radiographic examinations were taken at the baseline, preoperatively and at 3 and 6 months after regenerative surgery. RESULTS: Six months following therapy, both Atrisorb and Resolut XT groups had achieved comparable clinical improvement in pocket reduction (3.9 versus 4.4 mm), attachment tissue gain (clinical attachment gain; 3.5 versus 3.6 mm), and reduction in the GI and in the PII. Within-group comparisons showed significant attachment gain and pocket reduction between baseline data and those at both 3 and 6 months postoperatively (p < 0.01). There were no statistically significant differences in any measured data between groups A and B. CONCLUSIONS: The results of this study indicate that a comparable and favorable regeneration of periodontal defects can be achieved with both Atrisorb and Resolut XT barriers. Further long-term study and histologic observations of tissue healing are needed to evaluate whether Atrisorb is promising for clinical use.

Interleukin-1beta, clinical parameters and matched cellular-histopathologic changes of biopsied gingival tissue from periodontitis patients.

OBJECTIVE: The aim of the present study was to investigate whether interleukin (IL)-1beta in diseased tissues adjacent to periodontal pockets can reflect the degree of inflammation and destruction of these tissues pathologically. BACKGROUND: IL-1beta-dependent mechanisms have been strongly implicated in contributing to inflammation and destruction of bone and attachment loss, which are characteristic features of periodontal disease. This biochemical mediator released during pro-inflammatory processes has not been objectively integrated with clinical and histopathologic features of periodontal disease. METHODS: Periodontitis-affected inflamed tissue and clinically nonaffected healthy gingivae were harvested from 14 periodontal patients, respectively. The severity of tissue inflammation was illustrated by clinical parameters and cellular histologic changes and quantified by histometric assessments. IL-1beta in these extracted specimens was measured with an enzyme-linked immunosorbent assay (ELISA) technique. Pathogenic roles that IL-1beta plays in gingival inflammation and pathologic tissue changes in tissue sections were analyzed statistically. RESULTS: The overall total tissue IL-1beta, tissue concentration of IL-1beta, and percentage of inflammatory cell infiltration (PICI) determined from diseased gingivae were obviously higher than those of controls from both healthy sites of periodontitis and non-periodontitis subjects. With increasing gingival index (GI), plaque index (PlI), and probing depth (PD), there was a marked elevation in total tissue IL-1beta. Total tissue IL-1beta was significantly correlated with GI, PlI, the PICI, and tissue alterations. Polymorphonuclear leukocytes (PMNs) and monocyte-macrophage cells seemed to predominate in heavily infiltrated areas of diseased gingiva. These cell types were confirmed by immunocytochemical localization with either monoclonal mouse antihuman neutrophil elastase antibody or monoclonal mouse antihuman macrophage (CD68) antibody, respectively. Total tissue IL-1beta and the PICI were also elevated in diseased gingivae near deeper PD, while neither total IL-1beta nor tissue concentration was statistically correlated with PD. Thus, correlation analysis indicates that IL-1beta level in inflamed periodontal tissues correlates highly with clinical parameters (GI and PlI) and PICI (the degree of inflammation). CONCLUSIONS: These observations suggest that IL-1beta plays a significant role in the pathogenic mechanisms of periodontal tissue destruction, and that measurement of tissue IL-1beta would be a valuable aid and useful for diagnostic markers of periodontal diseases.

In vitro effect of laser irradiation on cementum-bound endotoxin isolated from periodontally diseased roots.

BACKGROUND: In a previous study, we evaluated the in vivo effects of an Nd:YAG laser on periodontal disease by measuring crevicular interleukin (IL)-1beta levels before and after laser application. It was found that laser therapy was less effective than traditional scaling and root planing. These results might be due to incomplete removal of microbial residues and cementum-bound endotoxin on root surfaces by the laser. In this study, we explored the in vitro effectiveness of an Nd:YAG laser for the elimination of cementum-bound endotoxin by measuring IL-1beta changes in stimulated monocytes. METHODS: Fresh human monocytes were harvested from adults without periodontitis and grown in RPMI 1640 medium. Diseased cementum particles were collected and prepared from teeth with untreated periodontitis and were irradiated with 5 levels of laser energy. Cementum particles were subjected to endotoxin testing by a limulus amebocyte lysate (LAL) assay and then were incubated with cultured monocytes. Production of IL-1beta in stimulated monocytes was measured by enzyme-linked immunosorbent assay and quantified by spectrophotometry. RESULTS: The endotoxin unit (EU) of diseased cementum was 18.4 EU/mg, which seemed to be remarkably lower than that of common periodontal pathogens including Porphyromonas gingivalis (381) at 15,300 EU/mg/ml, Prevotella intermedia (ATCC 25611) at 227 EU/mg/ml, and Fusobacterium nucleatum (ATCC 25586) at 1,987 EU/mg/ml. Monocytes subjected to stimulation by diseased cementum particles without laser irradiation produced 124 to 145 pg/ml IL-1beta, 9- to 18-fold higher than that of unstimulated monocytes (7.07 to 15.95 pg/ml). Diseased cementum particles after irradiation with various energy levels of the Nd:YAG laser could still stimulate monocytes to secrete 89 to 129 pg/ml IL-1beta. No statistically significant difference was found in the production of IL-1beta induced by diseased-bound cementum with or without laser irradiation. CONCLUSIONS: The Nd:YAG laser varying from 50 mJ, 10 pps to 150 mJ, 20 pps, for 2 minutes, did not seem to be effective in destroying diseased cementum endotoxin.