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Background Infection control is a major determinant of guided tissue regeneration (GTR). This study aims to develop an antibiotic-loaded membrane to assist periodontal repair. Methods Poly(D,L-lactic acid) (PDLLA) nanofibers encapsulating amoxicillin (PDLLA-AMX) were fabricated using the electrospinning technique, and their structures, drug encapsulation efficiency, and release characteristics were assessed. The viability and behaviors of periodontal ligament (PDL) cells on nanofibers, and antibacterial capabilities of nanofibers were evaluated in vitro. Early therapeutic efficiency of the antibiotic-loaded membranes was investigated in rats with ligature-induced experimental periodontitis, and the outcomes were evaluated by gene expression, microcomputed tomography imaging, and histology within 7 days of membrane placement. Results AMX was successfully encapsulated in the PDLLA nanofibers and released in a sustained manner. After initial attachment was achieved, cells stretched out along with the directions of nanofibers. The viability and expression of migration-associated gene of PDL cells were significantly improved, and the growth of Streptococcus sanguinis and Porphyromonas gingivalis was significantly reduced in the PDLLA-AMX group compared with the controls. On PDLLA-AMX-treated sites, wound dehiscence and sulcular inflammation were reduced. Collagen fiber matrix deposition was accelerated with upregulated type I collagen and interleukin-1β, and downregulated matrix metalloproteinase-8, whereas periodontal bone level and the expressions of vascular endothelial growth factor and core-binding factor subunit alpha-1 were equivalent to conventional membrane treatment. Conclusions PDLLA-AMX nanofibers inhibited bacterial growth and promoted the viability and mobility of PDL cells after initial cell attachment. Membranes with PDLLA-AMX nanofibers reduced inflammation and accelerated periodontal repair at an early stage, providing good prospects for the further development of GTR membranes.

This study aimed to evaluated the potential of core-shell poly(D, l -lactide-co-glycolide)-chitosan (PLGA-chitosan) nanospheres encapsulating simvastatin (SIM) and doxycycline (DOX) for promoting periodontal and large-sized osseous defects. SIM, and/or DOX were encapsulated in PLGA-chitosan nanospheres using double emulsion technique and were delivered to sites of experimental periodontitis and large-sized mandibular osseous defects of rats for 1–4 weeks. The resultant nanospheres were ~ 200 nm diameter with distinct core-shell structure and released SIM and DOX sustainably for 28 days. DOX and SIM-DOX nanospheres significantly inhibited P. gingivalis and S. sanguinis. In experimental periodontitis sites, SIM-DOX nanospheres significantly down-regulated IL-1b and MMP-8 and significantly reduced bone loss. In mandibular osseous defects, VEGF was up-regulated, and osteogenesis was significantly augmented with SIM nanospheres treatment. In conclusion, core-shell PLGA-chitosan nanospheres released SIM and DOX sustainably. SIM-DOX and SIM nanospheres could be considered to promote the repair of infected periodontal sites and non-infected osseous defects respectively.

The aims of this study were to identify the microbiological changes in the periodontal pockets following an Er:YAG laser (ERL) irradiation and mechanical debridement to compare the effectiveness of ERL irradiation to mechanical debridement for peri-implantitis treatment through randomized controlled trials. Twenty-three patients with peri-implantitis lesions were treated in either a test group, ERL set at energy level of 100 mJ/pulse, frequency of 10 Hz, pulse duration was 100 µs, and irradiated by three passages, or a control group, with mechanical debridement using an ultrasonic scaler. An examiner measured the following clinical parameters at different stages (a baseline and at 3- and 6-month post-treatment): probing depth (PD), bleeding on probing (BOP), marginal bone loss (MBL), and anaerobic bacteria counts. Linear regression, with generalized estimation equations, was used to compare the clinical parameters and anaerobic bacterial counts at different stages and between groups. The anaerobic bacterial counts significantly decreased within the control group during the follow-ups. At the 6-month follow-up, both groups showed a significant reduction in PD (test group: mean difference of 0.84 mm; control group: mean difference of 0.41 mm), and the test group showed a significantly higher PD reduction on the buccal site (1.31 mm) compared to that of the control group (0.25 mm). Both ERL and mechanical debridement treatments led to significant improvements in PD. When mechanical debridement therapy was used, significant anaerobic bacterial count reductions were observed. Future treatment of peri-implantitis should involve a combination of both of these therapies.

Purpose: To investigate the effect of Er:YAG laser treatment on lipopolysaccharide (LPS) clearance and fibroblast adhesion in an ex vivo peri-implantitis model. Methods: Grade IV titanium discs (n = 216) were used and allocated to 6 groups. Group 1 was the negative control without Porphyromonas gingivalis inoculation. Discs in Groups 2 to 6 were incubated with P. gingivalis to form a biofilm. Group 3 received 0.12% chlorhexidine irrigation and Group 4 received titanium curettage to remove the biofilm. Group 5 was treated with Er:YAG laser irradiation and Group 6 was treated with titanium curettage plus Er:YAG laser irradiation. The contact angle and surface roughness were measured after the various treatments. The surface microstructure and residual bacteria were examined using scanning electron microscopy and confocal laser scanning microscopy, respectively. Residual LPS was examined using a limulus amoebocyte lysate assay and human gingival fibroblast adhesion was quantified using fluorescent microscopy. Results: Curettage plus Er:YAG laser irradiation was the most effective method for removing bacteria and LPS. No significant difference in the amount of fibroblast adhesion was found between the control and Group 6. Conclusion: Combined use of Er:YAG laser irradiation and curettage is a promising therapy for managing peri-implantitis .

Background/purpose Streptococcus sanguinis is an early colonizer of biofilm and plays a key role in the process of adhesion to prosthetic surfaces by facilitating the adhesion of later colonizers. The main aim of this study was to determine if S. sanguinis is affected by the gold concentration dental prosthetic alloys. Materials and methods Five commonly used alloys with varying degrees of gold concentration were selected for this study. We evaluated the ability of S. sanguinis ATCC strain 10556 to adhere to each of these alloys by counting the number of cells that adhered to each of the tested alloys. Each alloy was also assessed for cell adherence using scanning electron microscopy. One-way analysis of variance and Student–Newman–Keuls comparison test were used for statistical analysis based on cell counts from each well for the test and control groups. Results The highest concentration of bacterial cells adhered best to pure gold alloy (458±8) followed by 88.4% gold Je alloy (382.33±2), 56% gold Wi alloy (269±4), 2% gold Es alloy (212.33±2), and nongold Re alloy (183±3). Based on the cell counts and scanning electron microscopy observations, there was a clear correlation between gold concentration and S. sanguinis adherence. Conclusion The findings of this study suggest that alloys with a lower gold concentration may result in lower bacterial colonization rates and may reduce the risk of invasive infections. When choosing an alloy, low gold concentrations may be a better clinical choice.

Currently used guided tissue regeneration (GTR) membranes are mainly used as a barrier to prevent epithelial cells growth into defects before new bone formation. The aim of this study was to develop a tri-layer functional chitosan (CS) membrane with epigallocatechin-3-gallate (EGCG) grafted on the outer layer for bactericidal activity, and lovastatin was included in the middle layer for controlled release. Successful EGCG grafting was demonstrated using Fourier transform infrared spectroscopy and EGCG grafting significantly enhanced adhesion and proliferation of human gingival fibroblasts. The release duration of lovastatin reached 21days. CS-Lovastatin1 produced the highest alkaline phosphatase activity and EGCG14-CS exhibited the best bactericidal activity against periodontopathic bacteria. Finally, the EGCG14-CS-Lovastatin1 membrane showed a higher percentage of bone regeneration than BioMend(®) and control groups in one-walled defects of beagle dogs. These results suggest that the EGCG14-CS-Lovastatin1 membrane has the potential to be used as a novel GTR membrane.

Background Studies have reported a high prevalence of peri-implantitis. The etiology of peri-implantitis remains unclear and no available treatments result in total resolution of established peri-implantitis. Purpose To investigate the factors that interfere with osteoblast adhesion to contaminated titanium surfaces after different surface treatments. Materials and methods Grade 4 titanium discs were randomly divided into 5 groups and each group was divided into 2 subgroups, with one contaminated with Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), and the other contaminated with Porphyromonas gingivalis (P. gingivalis). Group 1 did not receive bacterial inoculation or surface debridement and served as a control. Group 2 received A. actinomycetemcomitans or P. gingivalis inoculation, separately. Group 3 received bacterial inoculation and titanium curette debridement, followed by normal saline irrigation. Group 4 received bacterial inoculation, curette debridement, normal saline irrigation, and ultrasonication. Group 5 received bacterial inoculation, curette debridement, normal saline irrigation, and placement in 0.12% chlorhexidine. After various surface treatments, the surface roughness and hydrophilicity of the titanium surface were measured, the number of adhered osteoblast cells was calculated, and the amount of residual lipopolysaccharide (LPS) was quantified. Results A. actinomycetemcomitans and P. gingivalis biofilms noticeably reduced surface hydrophilicity. Groups 3-5 showed decreased hydrophilicity and fewer adhered osteoblast cells compared with the control group. Although ultrasonication was more effective in removing LPS than curette debridement and chlorhexidine, cell adhesion was not as high as with clean titanium discs. Conclusions The non-surgical treatment used in this study was not effective in removing LPS from titanium surfaces and increasing osteoblast adhesion. A more effective method to remove LPS completely is required to enhance the treatment outcome of peri-implantitis.

Bor-Shiunn Lee,1 Chien-Chen Lee,2 Yi-Ping Wang,2 Hsiao-Jan Chen,3 Chern-Hsiung Lai,4 Wan-Ling Hsieh,1 Yi-Wen Chen2 1Graduate Institute of Oral Biology, 2Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University and National Taiwan University Hospital, 3Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, 4College of Life Science, Kaohsiung Medical University, Kaohsiung, Taiwan Abstract: Chronic periodontitis is characterized by inflammation of periodontal tissues, leading to bone resorption and tooth loss. The goal of treatment is to regenerate periodontal tissues including bone and cementum lost as a consequence of disease. The local delivery of tetracycline was proven to be effective in controlling localized periodontal infection without apparent side effects. Previous studies suggested that lovastatin has a significant role in new bone formation; however, the local delivery of lovastatin might enhance its therapeutic effects. A number of local delivery devices have been developed recently, including poly(D,L-lactide-co-glycolide acid) (PLGA) nanoparticles. The aim of this study was to develop a local delivery device, PLGA-lovastatin-chitosan-tetracycline nanoparticles, which allows the sequential release of tetracycline and lovastatin to effectively control local infection and promote bone regeneration in periodontitis. The size and microstructure of nanoparticles were examined by transmission electron microscopy, Nanoparticle Size Analyzer, and Fourier transform infrared spectroscopy. The release of tetracycline and lovastatin was quantified using a UV-Vis spectrophotometer. Furthermore, the cytotoxic effect and alkaline phosphatase activity of the nanoparticles in osteoblast cell cultures as well as antibacterial activity against periodontal pathogens were investigated. Finally, the bone regeneration potential of PLGA nanoparticles in three-walled defects in beagle dogs was investigated. The results indicated that PLGA-lovastatin-chitosan-tetracycline nanoparticles showed good biocompatibility, antibacterial activity, and increased alkaline phosphatase activity. The volumetric analysis from micro-CT revealed significantly increased new bone formation in defects filled with nanoparticles in dogs. This novel local delivery device might be useful as an adjunctive treatment in periodontal regenerative therapy. Keywords: lovastatin, tetracycline, chitosan, poly(d,l-lactide-co-glycolide acid), periodontal regeneration

The acid tolerance response (ATR) is one of the major virulence traits of Streptococcus mutans . In this study, the role of GlnR in acid-mediated gene repression that affects the adaptive ATR in S. mutans was investigated. Using a whole-genome microarray and in silico analyses, we demonstrated that GlnR and the GlnR box (ATGTNAN 7 TNACAT) were involved in the transcriptional repression of clusters of genes encoding proteins involved in glutamine and glutamate metabolism under acidic challenge. Reverse transcription-PCR (RT-PCR) analysis revealed that the coordinated regulation of the GlnR regulon occurred 5 min after acid treatment and that prolonged acid exposure (30 min) resulted in further reduction in expression. A lower level but consistent reduction in response to acidic pH was also observed in chemostat-grown cells, confirming the negative regulation of GlnR. The repression by GlnR through the GlnR box in response to acidic pH was further confirmed in the citBZC operon, containing genes encoding the first three enzymes in the glutamine/glutamate biosynthesis pathway. The survival rate of the GlnR-deficient mutant at pH 2.8 was more than 10-fold lower than that in the wild-type strain 45 min after acid treatment, suggesting that the GlnR regulon participates in S. mutans ATR. It is hypothesized that downregulation of the synthesis of the amino acid precursors in response to acid challenge would promote citrate metabolism to pyruvate, with the consumption of H + and potential ATP synthesis. Such regulation will ensure an optimal acid adaption in S. mutans .

The endophytic extracts from 19 endophytes, isolated from 13 species of Taiwanese plants, were evaluated for biological activity, including cytotoxicity, anti-platelet aggregation, and anti-inflammatory activity. The extracts of 12 endophytes exhibited inhibitory effects on collagen-induced platelet aggregation with IC50 values of 19.85–87.64 μg/ml. Four strains, Rahnella aquatilis, Pantoea agglomerans, Rhodotorula sp., and Penicillium paxilli, also showed inhibitory effects on thrombin-induced platelet aggregation with IC50 values of 42.80–61.54 μg/ml. Additionally 12 extracts of endophytes exhibited cytotoxicities with IC50 values of 0.12–19.83 μg/ml. However, eight extracts revealed inhibitory effects on superoxide anion generation induced by fMLP (N-formyl-l-methionyl-l-leucyl-l-phenylalanine) in human neutrophils. The extract of Rahnella aquatilis showed anti-platelet aggregation activity, and bioassay-directed fractionation led to the isolation of six compounds, including one isoalloxazine: lumichrome (1); two isoflavones: genistein (2) and daidzein (3); two cyclic peptides: cyclo-Pro-Val (4) and cyclo-Pro-Phe (5); and one benzenoid: methyl 2,4,5-trimethoxybenzoate (6). These results indicated that endophytes from Taiwanese herbal plants could be useful sources for research and development of bioactive lead compounds from nature.

Calcium phosphate and silicate-modified gold surfaces have potential applications in orthopedic and dental reconstruction, especially when combined with bone cement or dental resins. The aim of this study was to evaluate the formation of a Si – Na – Ca – P glass system nanoshell on functionalized gold nanoparticles. Stable gold nanoparticle suspensions were prepared by controlled reduction of HAuCl 4 using the sodium citrate method to obtain a nanogold-mercaptopropyltrimethyloxysilane (MPTS)–silicate–tetraethylothosilicate (TEOS)-capped particle solution. The nanoshells were formed when directly reacted with a 10-4 M calcium phosphate ion solution. The median nanoparticle diameter was observed to be 15 nm. The MPTS–silicate–TEOS–functionalized nanoshell more effectively formed a glass shell as compared with a nonsilicate nanoshell. The changes in the surface morphology and composition were observed by a scanning transmission electron microscope equipped with energy-dispersive X-ray spectroscopy. As seen using EDS, the nanoshell was in a glass phase with CaO -poor layers.

Calcium phosphate and silicate-modified gold surfaces have potential applications in orthopedic and dental reconstruction, especially when combined with bone cement or dental resins. The aim of this study was to evaluate the formation of a Si–Na–Ca–P glass system nanoshell on functionalized gold nanoparticles. Stable gold nanoparticle suspensions were prepared by controlled reduction of HAuCl4 using the sodium citrate method to obtain a nanogold-mercaptopropyltrimethyloxysilane (MPTS)–silicate–tetraethylothosilicate (TEOS)-capped particle solution. The nanoshells were formed when directly reacted with a 10-4 M calcium phosphate ion solution. The median nanoparticle diameter was observed to be 15 nm. The MPTS–silicate–TEOS–functionalized nanoshell more effectively formed a glass shell as compared with a nonsilicate nanoshell. The changes in the surface morphology and composition were observed by a scanning transmission electron microscope equipped with energy-dispersive X-ray spectroscopy. As seen using EDS, the nanoshell was in a glass phase with CaO-poor layers.

Introduction The main objective of this study was to assess the efficacy of a new and innovative method of harvesting bacteria that are aerosolized during orthodontic debonding. Additionally, the protection efficacy of several commercially available masks from such aerosols was assessed in a pilot study. Methods Twenty-six subjects were debonded during aerosol sampling, by using an innovative collection system to harvest bonding dust liberated during debonding. Dark-field microscopy, gram-stain microscopy, and chemical identification were used to determine speciation of the collected aerosol from 23 subjects. Three additional subjects were used to test 3 commercial dental or protective masks to determine whether they provide effective protection from the aerosol. Results Twenty-one species of oral bacteria were identified by the new sampling technique. Two of the 3 masks that were tested offered no protection against the aerosolized bacteria. Conclusions A new and effective method for collecting airborne bacteria is presented. Some conventional dental masks offer no protection from aerosolized organisms liberated during debonding procedures. Further assessment of mask efficacy is ongoing.

This study was an attempt to clarify whether the bactericidal effects of photodynamic therapy (PDT) are wavelength or dose-dependent. We also attempted to create an optimised protocol for a light-based bactericidal modality to eliminate periodontal pathogens. Cultures of Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Porphromonas gingivalis, Prevotella intermedia, and Streptococcus sanguis, were exposed to a He-Ne laser (632.8 nm) with a 30 mW power output, a 100 mW diode laser at 665 nm, or a 100 mW diode laser at 830 nm, in the presence or absence of methylene blue (MB) as a photosensitiser. A control group was also used with exposure to MB alone without laser exposure. The cultures were analysed by viable counts. The results indicated that exposure to the 100 mW laser light could eliminate up to 40% of bacteria on average. In particular, the most effective killing occurred with exposure to laser light in combination with the MB photosensitiser. The results of kinetic studies indicated that the best PDT response rate was achieved with a 60 s (energy density 21.2 J/cm(2)) exposure to the 665 nm wavelength diode laser in the presence photosensitiser. In this condition, approximately 95% of A. actinomycetemcomitans and F. nucleatum, and 99-100% of the black-pigmented bacteria ( P. gingivalis and P. intermedia) and S. sanguis were eliminated. These results showed that both wavelength and energy density are important factors, and that a low power laser of optimal wavelength and dosage, in combination with an appropriate photosensitiser, is a practical bactericidal modality. We concluded that using a diode laser of proper power and wavelength to deliver 60 s of irradiation could be a useful adjunct with mechanical debridement in the prevention of the re-colonisation of subgingival lesions by pathogenic microorganisms.

Objective This study attempts to reveal how nanocrystallites on the ceramic surfaces of non-dispersive calcium phosphate cement (nd-CPC) participate in setting processes as compared with conventional CPC (c-CPC). Methods The compositions and morphologies of CPC during the early setting reactions were studied with X-ray diffraction and a scanning transmission electron microscope equipped with an energy dispersive spectroscopy system. The pH values and dispersive properties of CPC during the early setting reactions were investigated as well as the compressive strength of nd-CPC after 24 h of immersion with varying liquid to powder ratios. Results The mechanical strength of nd-CPC was approximately 60 MPa after a 24 h immersion in simulate body solution with a P/L ratio between 3.3 and 4.2 g/mL. The nanocrystallites on the particle surfaces of nd-CPC were shown to grow rapidly and provided interlocking sites that allowed rapid development of the apatite phase in the cement, and were also shown to be non-dispersive in solution as determined by an injection test of c-CPC. Conclusions The interlocking particles produced by whisker growth on the ceramic particles or new crystallites formed between the ceramic particles caused the cement to be non-dispersive in solution. The particles of reactants with nanocrystallites on surfaces also gave this cement the ability to be shaped easily as a paste during an operation or to be injected into a cavity.

The aim of this study was to evaluate the effects of herbal medicines in treating periodontal diseases. Three Chinese herbal composites [Conth Su (CS), Chi Tong Ning (CTN) and Xi Gua Shuang (XGS)], widely used for prevention and treatment of periodontal diseases, and the major components of these composites were tested for their ability to: (1) alleviate disease progression of experimental periodontitis in hamsters, (2) inhibit bacterial growth, and (3) induce mutations. Our results indicate that in treating experimental periodontitis, there were no significant differences between the animal groups with or without the use of Chinese herbal medicines in terms of the degree of inflammation, alveolar bone resorption, and rate of repair. However, hamsters treated with CS presented earlier regenerative epithelium. CTN demonstrated superior bacterial inhibition ability among all tested herbs (MIC 0.025 g/ml); CS showed good anti-bacterial abilities at a concentration of 0.05 g/ml. It is interesting to note that while both CS and CTN were capable of inhibiting bacterial growth, none of the individual herb components showed comparable bacterial inhibition abilities. None of the tested herbal composites or their components showed signs of inducing cell mutations using the Ames test. These results indicated that traditional Chinese herbal medicines, which have been used to treat periodontal diseases for hundreds of years by Chinese people, can effectively inhibit bacterial growth without causing cell mutation. Further investigation into their possible clinical applications in periodontal therapy is encouraged.

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