Is periodontitis a risk factor of benign or malignant colorectal tumor? A population-based cohort study.

OBJECTIVE: To examine the risk of developing benign or malignant colorectal tumors in patients with periodontitis within 15 years using Taiwan's National Health Insurance Database. BACKGROUND: Studies have shown that colorectal carcinoma often develops under inflammatory conditions and changes of microbiota in the gut. Recently, a link between Fusobacterium nucleatum, a periodontal pathogen, and colorectal carcinoma has been proposed. However, whether periodontitis is a risk of developing colorectal tumor remains uncertain. METHODS: In total, 35 124 participants were enrolled from 2000 to 2015 to examine the development risk of benign colorectal tumors, including 11 708 patients with periodontitis who received therapy (group 1), 11 708 patients with periodontitis not receiving periodontal treatment (group 2), and 11 708 non-periodontitis controls after matching for gender, age, and index year. To examine the risk of developing colorectal malignancy, 11 720 participants were assigned to each of the three groups. Cox proportional hazards model and Kaplan-Meier methods were used to compare the risks. Sensitivity analysis was performed, excluding the diagnoses during the first 1 or 5 years. RESULTS: After the follow-up, 177, 154, and 63 participants in group 1, group 2, and control group had benign colorectal tumors. Patients with periodontitis tended to be associated with a greater rate of having a benign colorectal tumor. The adjusted hazard ratios (aHRs) were 3.77 (95% confidence interval [CI] 2.01-4.82, p < .001) and 2.85 (95% CI 1.62-3.74, p < .001) for groups 1 and 2, respectively. Regarding the risk of malignant colorectal tumor, 20, 18, and 14 participants who developed malignant tumors were included in group 1, group 2, and control group; however, no significant increase in malignancy was observed in periodontitis groups (aHR1.92, 95% CI 0.74-2.36, p = .482; aHR 1.50, 95% CI 0.68-1.97, p = .529, for the two periodontitis groups, respectively). CONCLUSIONS: The results of this study suggest that patients with periodontitis may have an increased risk of developing benign, but not malignant, colorectal tumors.

Antioxidants protect against gingival overgrowth induced by cyclosporine A.

OBJECTIVE: We investigated the importance of reactive oxygen species (ROS) on developing gingival overgrowth (GO) and then introduced the antioxidant strategy to prevent, or even reduce GO. BACKGROUND: Gingival overgrowth is a common side effect of the patients receiving cyclosporine A (CsA), an immune suppressant. Although it has been broadly investigated, the exact pathogenesis of the induced GO is still uncertain. METHODS: We cultured human primary gingival fibroblasts and used animal model of GO to investigate the ameliorative effects of antioxidants on CsA-induced GO. To examine the CsA-induced oxidative stress, associated genes and protein expression, and the overgrown gingiva of rats by using immunocytochemistry, confocal laser scanning microscopy, real-time PCR, ELISA, gelatin zymography, gingival morphological, and immunohistochemical analysis. RESULTS: We found for the first time that ROS was responsible for the CsA-induced oxidative stress and TGF-ß1 expression in human primary gingival fibroblasts, as well as the GO of rats. The antioxidants (oxidative scavenger of vitamin E and an antioxidative enzyme inducer of hemin) ameliorated CsA-induced pathological and morphological alterations of GO without affected the CsA-suppressed il-2 expression in rats. CsA-induced oxidative stress, HO-1, TGF-ß1, and type II EMT were also rescued by antioxidants treatment. CONCLUSIONS: We concluded that CsA repetitively stimulating the production of ROS is the cause of CsA-GO which is ameliorated by treating antioxidants, including vitamin E and sulforaphane. Furthermore, the immunosuppressive effect of CsA is not interfered by antioxidant treatments in rats. This finding may thus help the clinician devise better prevention strategies in patients susceptible to GO.

Effectiveness of an oral function intervention for older Taiwanese people.

OBJECTIVE: Oral function disorders occur often in older people with increasing age. Oral function disorders affect bodily function and self-esteem, which are related to quality of life (QOL). The aim of this study was to evaluate the effectiveness of an oral function intervention programme on the oral function of older Taiwanese people. MATERIALS AND METHODS: A one-group pretest-post-test study design was used. A total of 529 older Taiwanese people (women, 68.2%; men, 31.8%; average age, 75.07 ± 5.95 years) participated in this study. The oral function intervention programme consisted of a brief oral health education programme and oral function exercises. The total test period was 8 months. The oral condition and function examination comprised two questionnaires (self-reported symptoms of oral function disturbance and the Geriatric/General Oral Health Assessment Index [GOHAI]) and three oral function assessments (Repetitive Saliva Swallowing Test [RSST], Oral Diadochokinesia Test [ODT] and Cheek Expanding Test [CET]). RESULTS: After the oral function intervention, the self-reported symptoms on the oral function questionnaire and GOHAI showed significant improvement (P < 0.05). Additionally, RSST, ODT and CET showed differences between pretest and post-test measurements (P < 0.05). CONCLUSION: The oral function intervention programme was effective in maintaining their feeding, swallowing and articulatory functions of older Taiwanese people. Significant improvements in self-reported symptoms of oral function and GOHAI scores indicated that the oral function intervention programme might improve the QOL of older Taiwanese people.

Role of Shh and TGF in cyclosporine-enhanced expression of collagen and α-SMA by gingival fibroblast.

OBJECTIVE: Cyclosporine-A (CsA)-induced gingival overgrowth may arise from an alteration in stoma matrix homeostasis. Sonic hedgehog (Shh) plays a key role during embryogenic development and fibrotic progression, and may be involved in CsA-altered gingival matrix homeostasis. METHODS: Using the reverse transcription-polymerase chain reaction and Western blot analysis, we investigated the mRNA and protein expressions of Shh, type 1 collagen (COL1), alpha-smooth muscle actin (α-SMA) and transforming growth factor-beta (TGF-ß) in human gingival fibroblasts after CsA treatments. The effect of Shh on CsA-induced alterations was further evaluated by the extra-supplement or inhibition of Shh or TGF-ß. RESULTS: Cyclosporine-A enhanced COL1, α-SMA, Shh and TGF-ß expressions in human gingival fibroblasts. The exogenous Shh/TGF-ß augmented the expression of COL1 and α-SMA, and the Shh/TGF-ß inhibition suppressed the CsA-enhanced COL1 and α-SMA expressions. Moreover, Shh mRNA and protein expressions increased if extra-supplementing the exogenous TGF-ß, whereas the CsA-upregulated Shh was mitigated by the TGF-ß pathway inhibitor. However, neither exogenous Shh nor the Shh pathway inhibitor alters TGF-ß expression or CsA-up-regulated TGF-ß expression. CONCLUSIONS: Shh, regulated by TGF-ß, mediates CsA-altered gingival matrix homeostasis.

Bifid mandibular canals and the factors associated with their presence: a medical computed tomography evaluation in a Taiwanese population.

OBJECTIVES: To examine distribution of bifid mandibular canals in a Taiwanese population and to evaluate factors contributing to the phenomenon. MATERIAL AND METHODS: Computed tomographic images from 173 subjects (97 females and 76 males) were obtained using a 64-slice multidetector computerized tomography system, and the presence of bifid mandibular canals, as well as their widths and lengths, was examined. Association of length of bifid canals with possible contributing factors, including gender, age, and side of presentation, as well as size of cross-sectional bony area of mandible along the long axis of mandibular canal, was evaluated. RESULTS: Bifid mandibular canals, with mean values of 10.1 and 0.9 mm in length and width, were found in 53 (30.6%) of 173 patients and 64 (18.5%) of 346 hemi-mandibles. Bifid canals appeared more frequently and tend to penetrate mandible with greater lengths in males if compared with those in females. When males were compared with females and when mandibles with bifid canals were compared with ones without, the former tend to present with larger bony area at corresponding levels of cross-sectional plane than the later, respectively. By regression analysis, significant association was found between length of bifid canals and gender, side of hemi-mandible, and bony area at mid-zone of mandibular canal. CONCLUSIONS: Bifid canals were observed in 30.6% of subjects and 18.5% of hemi-mandibles. Significant association between length of bifid canals and gender, side of hemi-mandible, and cross-sectional bony area of mandible was observed.

Effects of bone morphogenetic protein-6 on periodontal wound healing/regeneration in supraalveolar periodontal defects in dogs.

OBJECTIVE: Application of a synthetic BMP-6 polypeptide in a rat periodontal fenestration defect model enhanced periodontal wound healing/regeneration including new bone and cementum formation. The purpose of this study was to translate the relevance of these initial observations into a discriminating large animal model. METHODS: Critical-size (4-5 mm) supraalveolar periodontal defects were created at the 2(nd) and 3(rd) mandibular premolar teeth in 11 Beagle dogs. Experimental sites received BMP-6 at 0.25, 1.0 and 2.0 mg/ml soak-loaded onto an absorbable collagen sponge (ACS) carrier or ACS alone (control) each condition repeated in four jaw quadrants. The animals were euthanized at 8 weeks when block biopsies were collected and processed for histologic/histometric analysis. RESULTS: BMP-6 at 0.25, 1.0 and 2.0 mg/ml soak-loaded onto the ACS yielded significantly enhanced new bone (0.99 ± 0.07 versus 0.23 ± 0.13 mm/BMP-6 at 0.25 mg/ml) and cementum (2.45 ± 0.54 versus 0.73 ± 0.15 mm/BMP-6 at 0.25 mg/ml) formation including a functionally oriented periodontal ligament compared with control (p < 0.05). A significant inverse linear association between BMP-6 dose and new bone (ß = -0.21 ± 0.09 mm, p = 0.016) and cementum height (ß = -0.34 ± 0.15 mm, p = 0.023) was observed. Minimal root resorption was observed without significant differences between groups. Ankylosis was not observed for any of the experimental groups. CONCLUSIONS: Surgical application of BMP-6/ACS onto critical-size supraalveolar defects enhanced periodontal wound healing/regeneration, in particular cementogenesis including a functionally oriented periodontal ligament; the low BMP-6 0.25 mg/ml concentration apparently providing the most effective dose.

Can chlorhexidine mouthwash twice daily ameliorate cyclosporine-induced gingival overgrowth?

BACKGROUND/PURPOSE: Gingival overgrowth can be induced in patients treated with cyclosporine-A (CsA), an immunosuppressant often used following organ transplantation. A pre-existing rat model designed to mimic CsA-induced gingival overgrowth in humans was used to test the effectiveness of frequent application of a chlorhexidine antiplaque solution in reducing the overgrowth. METHODS: Four groups of rats were fed CsA. One group received chlorhexidine mouthwash twice a day, the second group received chlorhexidine mouthwash once a day, the third group received chlorhexidine mouthwash every other day, and the fourth group did not receive chlorhexidine mouthwash all. A fifth negative control group received only mineral oil. Overgrowth was determined by measuring the changes in the gingival probing depth and the keratinized gingival width on molars. A gingival histological examination was performed. RESULTS: Rats treated with mouthwash twice daily exhibited decreased probing depths and gingival widths without statistical significance. Histological examination revealed that CsA treatment caused gingival enlargement, whereas chlorhexidine treatment twice a day diminished the enlargement. CONCLUSION: These findings suggest that chlorhexidine mouthwash used twice daily may reduce the severity of CsA-induced gingival overgrowth. Further research is warranted to determine the optimal dose and treatment regimen.

Type 2 Diabetes Mellitus and Periodontitis: Bidirectional Association in Population-based 15-year Retrospective Cohorts.

OBJECTIVE: A two-way relationship between periodontitis and diabetes has been proposed. However, bidirectional epidemiological observation is limited and inconsistent. OBJECTIVE: Using the National Health Insurance Research Database of Taiwan (covering over 99% of the entire population), we aimed to estimate the development of diabetes in periodontitis patients or that of periodontitis in patients with type 2 diabetes mellitus (T2DM), respectively. METHODS: A total of 11 011 patients with severe periodontitis were recruited from 2000 to 2015. After matching by age, sex, and index date, 11 011 patients with mild periodontitis and 11 011 non-periodontitis controls were registered. Additionally, 157 798 patients with T2DM and 157 798 non-T2DM controls were enrolled, in whom the development of periodontitis was traced. Cox proportional hazards model was performed. RESULTS: Periodontitis patients tended to have a statistically high risk for T2DM. The adjusted hazard ratio was 1.94 (95% CI, 1.49-2.63, P < .01) and 1.72 (95% CI, 1.24-2.52, P < .01) for severe and mild periodontitis groups, respectively. The patients with severe periodontitis had a higher risk of having T2DM relative to those with mild periodontitis (1.17 [95% CI, 1.04-1.26, P < .001]). Conversely, the risk of periodontitis increased significantly in patients with T2DM (1.99 [95% CI, 1.42-2.48, P < .01]). However, high risk was observed for the outcome of severe periodontitis (2.08 [95% CI, 1.50-2.66, P < .001]), but not for mild periodontitis (0.97 [95% CI, 0.38-1.57, P = .462]). CONCLUSION: We suggest that the bidirectional association is between T2DM and severe but not mild periodontitis.

Prevalence and location of maxillary sinus septa in the Taiwanese population and relationship to the absence of molars.

OBJECTIVES: Understanding the septum structure of the sinus is necessary for correct implant placement in the maxilla if sinus encroachment is required. The exact mechanism that controls septum development is unclear, although a role for the irregular pneumatization of the sinus floor following tooth loss has been suggested. The aims of this study were to examine the prevalence and location of sinus septa in the Taiwanese population and to determine whether there is a relationship between the presence of septa and the absence of molars. MATERIALS AND METHODS: Using computed tomography (CT) scans of sinuses obtained from 423 subjects (216 women and 207 men, mean age 53.65 years), septum morphology and its correlation with the presence of molars was examined. RESULTS: About 30% of subjects (124/423) had sinus septa, corresponding to 20.45% of all sinus segments detected (173/846). Fifty-nine patients had multiple septa, giving a prevalence of septa of 22.93%. Septa were located most frequently in the regions of the first and second molars. The prevalence was not related to tooth loss (edentulous, partially edentulous, or dentate maxillary segments). Logistic regression analysis showed that men were significantly more likely to have septa than were women (OR=1.67; P=0.019). CONCLUSIONS: In the 423 Taiwanese subjects tested, the prevalence of septum was 29.31% according to the subjects and 22.93% according to the sinus segments. The most frequent location of septa was in the region of the first and secondary molars. No correlation was observed between the presence of septa and the absence of molars.

Cyanidin-3-O-glucoside downregulates ligation-activated endoplasmic reticulum stress and alleviates induced periodontal destruction in rats.

OBJECTIVE: Cyanidin-3-O-glucoside (C3G), a dietary anthocyanin, possesses various biological properties, including alleviating endoplasmic reticulum (ER) stress. This study examined the effect of C3G on periodontitis via ER stress in rats. DESIGN: Periodontitis was induced by placing silk sutures around maxillary second molars. C3G (0, 3, or 9 mg/kg) was fed on the day before ligation (10 rats/group). Further, 10 non-ligation control rats received deionized water. On day 8, gingivae were obtained to determine CCAAT/enhancer-binding protein homologous protein (CHOP), c-Jun N-terminal kinase (JNK), phospho-JNK (p-JNK), and nuclear factor-κB (NF-κB) by immunoblotting. Periodontal destruction was evaluated using micro-computed tomography (µCT) and histology. RESULTS: Gingival expression of CHOP, p-JNK/JNK, and NF-κB significantly increased in ligation rats (0 mg/kg C3G) than that in controls. However, protein expression in ligation groups presented a negative association with C3G concentration. By µCT, the distance of cemento-enamel junction to bone significantly increased in ligation groups; however, distances showed a negative association with C3G concentration. In the region of interest, bone volume and trabecular thickness and number significantly decreased in ligation groups but they were positively associated with C3G concentration. In terms of trabecular separation, opposite results were found. Histologically, infiltrated connective tissue (ICT) and periodontal destructions increased in ligation groups; however, they were negatively associated with C3G concentration. Moreover, ICT area is positively correlated with µCT- and histologically measured destructions and protein expression of CHOP, p-JNK/JNK, or NF-κB. CONCLUSION: C3G promotes favorable modulation of ER stress and alleviates destruction of periodontitis, which may imply a new strategy.

Immediate hyperbaric oxygen after tooth extraction ameliorates bisphosphonate-related osteonecrotic lesion in rats.

BACKGROUND: This study aims to assess whether hyperbaric oxygen (HBO) applied immediately after tooth extraction could ameliorate medication-related osteonecrosis of the jaw in rats. METHODS: To evaluate whether osteonecrosis could be successfully induced, healing of extraction maxillary molars was examined in 40 female Sprague Dawley rats received zoledronic acid (7.5 µg/kg) plus dexamethasone (1 mg/kg). Rats were divided into four groups, receiving zero, two, four, or seven injection(s) for 7 days, respectively. Effect of HBO, pressurized to 2.5 atmospheres absolute (ATA) at rate of 0.15 ATA/min with 100% oxygen for 90 minutes, applied immediately after tooth extraction, on the development of osteonecrosis was evaluated. Lesions among groups were compared by size of ulceration, exact area (mm2 ) or relative area (%), and by histology. RESULTS: Unhealed ridge was observed in all nine rats in four and seven injection groups, but none of 10 rats in the control (non-injection) group. Immediate HBO significantly reduced the lesions in rats that received four injections, regardless of the distribution and the total/relative areas of lesions (P <0.01). Histological findings showed the lesions were uncovered epithelium and severe tissue inflammation. CONCLUSION: This is the first in vivo study demonstrating the HBO applied immediately after tooth extraction effectively decreases the development of medication-related osteonecrosis.

Ameliorative effect of hesperidin on ligation-induced periodontitis in rats.

BACKGROUND: This study evaluated the ameliorative effect of hesperidin (HES), an anti-inflammatory flavanone, in rats with ligation (Lig)-induced periodontitis. METHODS: A total of 48 rats were randomly divided into non-ligation group (NL), Lig group, and two ligation-plus-HES groups (L+H). HES was administered immediately after ligature placement at a dose of 75 or 150 mg/kg by intragastric feeding. Destruction of the ligated maxillary second and mandibular first molars were evaluated by dental radiography, microcomputed tomography (micro-CT), and histometry performed after sacrificing the rats on the seventh day. The expression levels of interleukin (IL)-1ß, IL-6, and inducible nitric oxide synthase (iNOS) messenger (m)RNAs in the gingiva were determined by reverse-transcription polymerase chain reaction. The expression of iNOS was examined by immunohistochemistry. RESULTS: The dental radiography and micro-CT findings revealed significantly increased alveolar bone loss in the Lig group, which was significantly prevented by HES. The histometry results revealed less gingival inflammation and connective tissue loss in the L+H groups compared with that in the Lig group. The mRNA expression levels of IL-6, IL-1 ß, and iNOS were significantly increased in the Lig group but were reduced in the L+H groups. The immunostaining results showed that the ligation-induced iNOS expression was also decreased by HES. CONCLUSIONS: Oral administration of HES promotes an ameliorative effect against the ligation-induced alveolar bone loss and effectively inhibits the production of proinflammatory mediators in rats with experimentally induced periodontitis. Therefore, HES may be a good candidate for modulating oral inflammatory diseases.

Upregulation of heme oxygenase-1 expression in gingiva after cyclosporin A treatment.

BACKGROUND: Heme oxygenase (HO)-1 is a stress-inducible protein that confers cytoprotection, but its role in gingiva during cyclosporin A (CsA) therapy is unknown. We used in vivo and in vitro models to investigate the expression of mRNA and protein for HO-1 in gingiva upon CsA treatment. METHODS: Twenty-six male Sprague-Dawley rats were assigned to two groups after the establishment of edentulous ridges. Rats in the CsA group received CsA, 30 mg/kg/day for 4 weeks, whereas control rats received mineral oil only. All rats were killed after 4 weeks, and the edentulous gingivae were excised. mRNA and protein expression of HO-1 in gingivae were determined using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC), respectively. For the in vitro study, cultured human gingival fibroblasts were harvested after treatment with various concentrations of CsA, and HO-1 mRNA and protein expression were determined using RT-PCR and Western blotting, respectively. RESULTS: Mean gingival HO-1 mRNA expression was greater in the CsA group than in the control animals (P = 0.076). IHC staining for HO-1 protein was significantly greater in the gingivae of CsA-treated rats than in those of the control group. In fibroblast cultures, expression of HO-1 mRNA and protein also increased significantly after CsA treatment. CONCLUSION: CsA upregulates the gingival expression of HO-1, which may exert a cytoprotective effect.

Comparison of oral malodors before and after nonsurgical periodontal therapy in chronic periodontitis patients.

BACKGROUND/PURPOSE: Periodontal diseases have been considered as a source of oral malodor or halitosis. Improvement of oral malodor in chronic periodontitis patients has recently been observed after nonsurgical periodontal therapy in combination with tongue cleaning and/or chlorhexidine mouth rinsing. The present study, however, evaluated the impact of nonsurgical periodontal therapy alone on the oral malodor in chronic periodontitis patients by comparing the intraoral concentrations of volatile sulfur compounds (VSCs) before and after nonsurgical therapy. MATERIALS AND METHODS: Using a sulfide monitor, the total VSCs in exhaled breath were measured in 80 patients with chronic periodontitis prior to and 1 month after nonsurgical periodontal therapy (re-evaluation phase). Malodor was defined as a VSC score > 75 parts per billion (ppb) and > 110 ppb, respectively. RESULTS: Significantly lower level of VSCs was recorded at periodontal re-evaluation (55 ± 9.7 ppb) than before treatment (89 ± 16.3 ppb). Before treatment, 27 (34%) patients were considered to have malodor, defined as VSCs > 75 ppb. After treatment, 16 patients (20%) had VSC scores > 75 ppb, including 10 of 27 patients with baseline VSC scores > 75 ppb and six of 53 patients with baseline scores ≤ 75 ppb. The risk of malodor differed significantly before and after treatment (P = 0.035, McNemar's test). However, when malodor was defined as VSCs > 110 ppb, the difference in risk showed only borderline significance (P = 0.077). CONCLUSION: On the basis of our findings, we suggest that nonsurgical periodontal therapy has a mild impact on oral malodor.

Upregulation of the expression of epidermal growth factor and its receptor in gingiva upon cyclosporin A treatment.

BACKGROUND: To understand the roles of epidermal growth factor (EGF) and EGF receptor (EGF-R) in cyclosporin A (CsA)-induced gingival overgrowth, expression of EGF and EGF-R upon CsA treatment was examined in an oral epidermoid carcinoma cell line of humans (OECM-1) and in edentulous gingiva of rats. METHODS: In vitro study: after CsA treatment, OECM-1 cells were harvested to evaluate their mRNA and protein expression of EGF and EGF-R with reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and immunocytochemistry (ICC). In vivo study: 3 weeks after extraction of all maxillary molars, 20 male Sprague-Dawley rats were assigned to a CsA group (30 mg/kg, fed daily) and a control group. Five rats per group were sacrificed at weeks 1 and 4. Edentulous ridge specimens were obtained for evaluating their mRNAs and protein expression with RT-PCR, real-time RT-PCR, and immunohistochemistry (IHC). In both in vitro and in vivo experiments, the proliferating potential of epithelial cells was examined by the presence of proliferating cell nuclear antigen (PCNA). RESULTS: In vitro: dose-dependently increased mRNA expression of EGF and EGF-R in OECM-1 cells was noted after CsA treatment. Protein expressions of EGF and EGF-R were higher in OECM-1 with CsA treatment than without CsA. In vivo: higher mRNA and protein expressions of EGF and EGF-R were also observed in the gingival tissues of CsA-treated rats. In both in vitro and in vivo experiments, greater PCNA expression after CsA treatment was demonstrated. CONCLUSIONS: Higher expression of EGF and EGF-R upon CsA therapy was observed in OECM-1 epithelial cells of humans and in edentulous gingiva of rats. We suggest that CsA could upregulate gene and protein expression of EGF and EGF-R, and the upregulation may play a role in gingival overgrowth.

Cyclosporin-induced downregulation of the expression of E-cadherin during proliferation of edentulous gingival epithelium in rats.

BACKGROUND: To examine the role of E-cadherin in epithelial hyperplasia of cyclosporin A (CsA)-induced gingival enlargement, mRNA and protein levels of E-cadherin, beta-catenin, proliferating cell nuclear antigen (PCNA), and Cyclin D1 were examined in the edentulous gingiva of rats following CsA treatment. METHODS: Three weeks after the extraction of all maxillary molars, 20 male Sprague-Dawley rats were assigned to a CsA-fed group (30 mg/kg daily) or a control group. Five rats per group were sacrificed at weeks 1 and 4. Edentulous ridge specimens were taken, and the expression levels of E-cadherin, beta-catenin, Cyclin D1, and PCNA mRNAs were estimated by reverse transcription-polymerase chain reaction (RT-PCR). Tissue specimens of the week 4 groups were examined using immunohistochemical (IHC) staining for proteins. RESULTS: The mRNA expression of E-cadherin was significantly weaker in the CsA-treated group than the control group at both times. Using IHC staining, a weaker level of membrane-bonded E-cadherin was also observed in the gingival epithelial cells in the CsA group than in controls. By contrast, significantly stronger beta-catenin and Cyclin D1 mRNA expressions and protein levels were found in CsA-treated rats than controls by RT-PCR and immunohistochemistry at week 4, whereas PCNA production was stronger at both times. CONCLUSIONS: CsA treatment reduced the production of E-cadherin but increased the production of beta-catenin, Cyclin D1, and PCNA. Thus, CsA may downregulate E-cadherin gene expression, leading to the epithelial cell proliferation of gingival overgrowth.

Effects of Salvia miltiorrhiza ethanolic extract on lipopolysaccharide-induced dental alveolar bone resorption in rats.

BACKGROUND/PURPOSE: Salvia miltiorrhiza (SM) Bunge (Labiatae/Lamiaceae; common name danshen) is a Chinese medicine that improves blood circulation and inhibits inflammatory response. Thus, it is used for the treatment of cardiac diseases and inflammation. In this study, we aimed to evaluate the effect of an ethanolic extract of SM (SME) on the dental alveolar bone resorption induced by bacterial lipopolysaccharide (LPS) in rats. MATERIALS AND METHODS: An ethanolic extract was prepared from roots of SM. The major constituents of this extract were determined by high-performance liquid chromatography. The activity of the extract was evaluated in a rat model in which the dental alveolar bone resorption was induced by injection of bacterial LPS into the palatal gingiva around the maxillary molar teeth. The effect of SME on the bone resorption was studied by histologic and histomorphometric analysis. RESULTS: The number of osteoclasts and the percentage of osteoclasts covering the alveolar bone surfaces were significantly increased in the LPS group compared with those in the phosphate-buffered saline (PBS) group. The number and percentage of the osteoclasts on the bony surfaces were significantly reduced in the SME group in comparison with the LPS group, although it was still higher than the numbers observed in the PBS group. CONCLUSION: Because SME reduced bone resorption caused by the injections of bacterial LPS in rats, we suggest that SME might have a protective effect on dental alveolar bone resorption in periodontitis.

Bifid mandibular canals and their cortex thicknesses: A comparison study on images obtained from cone-beam and multislice computed tomography.

BACKGROUND/PURPOSE: High prevalence of bifid mandibular canals has been visualized with various types of computerized tomography (CT). Along the canals, a various ranged corticalization was recently reported. The depiction of the fine anatomic structures on multislice and cone-beam CT images was compared. MATERIAL AND METHODS: The presence or absence of the bifid canal was assessed on 327 images obtained by multislice CT (MSCT; n = 173) or by cone-beam CT (CBCT; n = 154), according to the configuration. The cortex thickness and distribution were also assessed. RESULTS: The prevalence of bifid canal detected by CBCT was significantly greater than that detected by MSCT (42.2% vs. 18.7% for hemi-mandibles and 58.4% vs. 30.6% for patients). Cortical thickness recorded by CBCT was significantly thinner than that recorded by MSCT (0.48 mm vs. 0.65 mm, P < 0.001); however, the distributions of corticalization detected by the two tomography methods were similar. There was a significant association of cortex thickness with CT type and corticalization degree (R 2 = 0.530, P < 0.001). CONCLUSION: Thinner cortices, but greater prevalence of bifid canals recorded by CBCT, compared to MSCT, suggests that clinicians should be cautious when using CT to interpret this fine anatomic structure.

Crosstalk Between Human Monocytic U937 Cells and Gingival Fibroblasts in Coculturally Enhanced Matrix Metalloproteinase-2 Expression.

BACKGROUND: Matrix metalloproteinases (MMPs) play a key role in inflammatory periodontal disease. Synergistically enhanced MMP-2 expression in a coculture of human gingival fibroblasts (HGFs) and human monocytic U937 cells was observed. Crosstalk between these two cells via the extracellular matrix metalloproteinase inducer (EMMPRIN) was demonstrated. METHODS: Enzyme levels of MMP-2 in HGFs and direct coculture with U937 were examined by zymography. MMP-2 and EMMPRIN expressions of HGFs and U937 were determined in coculture and conditioned cultures (using supernatants from HGF- or U937-conditioned medium). The crosstalk was evaluated by EMMPRIN extrasupplement and EMMPRIN inhibition, through pretreatment of U937 with cyclosporine-A. RESULTS: Direct coculturing of HGFs and U937 enhanced MMP-2 enzyme level and mRNA expression. Coculturing also increased membranous EMMPRIN expression of U937, but not from HGFs. In conditioned cultures, mRNA expression of MMP-2 increased in HGFs which received U937-conditioned medium. Increased MMP-2 was not observed in U937 with HGF-conditioned medium, although mRNA expression of EMMPRIN increased. Enhanced MMP-2 was observed after administration of exogenous EMMPRIN in HGFs; however, reduced MMP-2 enzyme level was noted if EMMPRIN of cocultured U937 was inhibited. CONCLUSIONS: In the coculture of HGFs and U937, upregulated EMMPRIN expression in U937, which may be triggered by HGFs, can enhance MMP-2 expression in HGFs. Crosstalk between HGFs and U937 involving MMP-2 from HGFs was proposed; EMMPRIN from U937 may play a particular role.

Upregulation of transforming growth factor-beta1 and vascular endothelial growth factor gene and protein expression in cyclosporin-induced overgrown edentulous gingiva in rats.

BACKGROUND: To examine the effects of cyclosporin A (CsA) on the expression of growth factors in induced gingival overgrowth with limited contributing factors arising from local inflammation caused by bacterial plaque, this study of gingival overgrowth was designed on the edentulous ridge of rats. METHODS: After a 3-week healing period following maxillary molar extractions, 16 five-week-old male Sprague-Dawley rats were assigned to CsA and control groups. Animals in the CsA group were fed 30 mg/kg CsA daily, whereas the control rats received a mineral oil vehicle instead. After 4 weeks, all animals were sacrificed, and the morphology of edentulous ridges was recorded by dental impression. The gingivae on the left-hand side were dissected and stored for mRNA analysis, whereas the gingivae on the right-hand side were fixed in 4% paraformaldehyde for immunohistochemistry (IHC) analysis of transforming growth factor-beta1 (TGF-beta1), platelet-derived growth factor beta (PDGF-beta), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF). RESULTS: The edentulous gingivae were enlarged and the body weights were reduced in the CsA-treated animals compared to controls. The mRNA expressions of TGF-beta1, IGF-1, and VEGF were higher in the gingivae of the CsA group than in the control group. In addition, a greater mRNA expression (7.21-fold) of VEGF was demonstrated in the CsA group than in the control group by real-time polymerase chain reaction (PCR). The percentages of cells staining positive for TGF-beta1 and VEGF were significantly greater in the CsA rats than in the control rats. CONCLUSIONS: Greater mRNA expression and positive staining for TGF-beta1 and VEGF were observed in the edentulous gingivae of rats that received CsA. Therefore, CsA may upregulate TGF-beta1 and VEGF gene expression and protein secretion in CsA-induced gingival overgrowth.