Influence of antibacterial effects of tetracycline, laser, and photodynamic therapy on cell viability, cell damage, and virulence of Porphyromonas gingivalis.

INTRODUCTION: This study compares and evaluates the efficacy of tetracycline, laser and photodynamic therapy on bacterial counts, cell damage, cell viability and neutralization of gingipains. MATERIAL AND METHODS: P.gingivalis (ATCC 33,277) was cultured anaerobically. The minimal inhibitory concentration (MIC) for 50% inhibition of P.gingivalis by tetracycline, laser, and toluidine blue (TB) was determined using spectrophotometry. The antibacterial effects, cell viability, cell damage and neutralization of gingipains of the treated groups was evaluated by microbial culture and counting, 2,3 Bis 2 Methyloxy-4 Nitro-5 Sulphophenyl 2 H tetrazolium-5-Carboxaanilide (MTT) assay, lactate dehydrogenase (LDH) assay, and gingipain assay (BAPNA). RESULTS: The MIC of tetracycline, toulidine, diode laser (810nmm; 0.5 Watts) is 1 µg/mL, 50 µg/mL and 15 s respectively. Comparative analysis for bacterial colony reduction was highest in tetracycline followed by PDT and then laser group at p < 0.01. MTT assay shows a significantly lesser number of viable cells in the tetracycline and PDT group when compared to laser group p < 0.01. Comparative analysis for cell damage using LDH shows the highest results for PDT followed by tetracycline and laser at p < 0.01. The highest neutralization of the gingipains is seen in the PDT group followed by tetracycline and laser groups at p < 0.01. CONCLUSION: PDT shows highest antibacterial activity, gingipain neutralization, cell damage, and least number of viable cells in comparison with tetracycline and laser.

Does Cigarette Smoking Induce Changes in Biologic and Mechanical Properties of Platelet-Rich Fibrin Membranes?

Smoking has a profound effect on platelet morphology and activation and has also been shown to affect hemostasis, coagulation, and healing cascade. To date, no previous reports are available to assess the impact of cigarette smoke on leukocyte- and platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF) membranes. Therefore, this study aims to analyze the impact of cigarette smoking on the mechanical and biologic properties of L-PRF and A-PRF membranes. Sixty blood samples from both smokers (n = 34) and nonsmokers (n = 26) who were matched for age and other factors were collected and subjected to complete blood count and platelet indices (mean platelet volume, platelet distribution width, platelet large cell ratio, and plateletcrit). The L-PRF membrane (2,700 rpm; 12 minutes) and A-PRF membrane (1,500 rpm; 14 minutes) were prepared using a standard protocol. A total of 64 experimental L-PRF and A-PRF membranes from 16 individuals selected randomly from the two groups were subjected to tensile strength evaluation using a micro universal testing machine and growth factor release analysis (platelet-derived growth factor [PDGF-AB], vascular endothelial growth factor [VEGF], and bone morphogenic protein-2 [BMP-2]) using ELISA (enzyme-linked immune sorbent assay). Results were tabulated, and statistical analysis was done using Mann-Whitney, Kruskal-Wallis, and Spearman correlation tests. Tensile strengths of L-PRF and A-PRF did not show a statistical difference between groups (P = .47). BMP-2 was not detected in any of the groups. A high initial release of PDGF-AB and VEGF was noticed in A-PRF samples from smokers. Although statistically insignificant, cigarette smoking does affect platelet activation and influences the tensile strength of L-PRF membranes as well as growth factor release in A-PRF membranes in smokers.

EDTA-S: A novel root conditioning agent.

BACKGROUND: To evaluate the efficacy of 15% ethylenediaminetetraacetic acid (EDTA)-S (EDTA with soft soap) preparation for the removal of smear layer at human root surfaces. MATERIALS AND METHODS: Twenty teeth indicated for extraction due to periodontal disease were sectioned using high speed cylindrical bur under copious irrigation. The root surfaces were instrumented with Gracey 7-8 curette (Hu-Friedy), 12 times to induce an "experimental smear layer". Following root planning, the root surface was cut using diamond disc and separated from the crown. Samples were randomly distributed into five groups. One group was control, saline and test groups were EDTA 15% alone, by active and passive applications (groups 2 and 3), and EDTA 15%+soft soap, by active and passive applications (groups 4 and 5). Specimens were then subjected to scanning electron microscope study. Smear layer removal was evaluated according to Sampaio et al., index. RESULTS: EDTA-S removed the smear layer better than plain EDTA and the control group, while active application of the root conditioning agent had significant difference than the passive application of the agent. CONCLUSION: EDTA-S has favorable benefits over EDTA alone, and active application is better in comparison with passive application of root conditioning agent. CLINICAL RELEVANCE: Removal of smear layer has been considered as an important step in periodontal regenerative therapy. Scaling and root planning alone with saline irrigation does not remove the smear layer. EDTA is a commonly used root conditioning agent in periodontal therapy. The addition of a detergent to EDTA proved to remove smear layer more efficiently than EDTA alone.

A comparative evaluation of the antibacterial efficacy of honey in vitro and antiplaque efficacy in a 4-day plaque regrowth model in vivo: preliminary results.

BACKGROUND: Honey has a potent broad-spectrum antibacterial action that may make it suitable for "anti-infective" treatment of periodontal disease. The aims of this study are as follows: 1) to evaluate the antibacterial efficacy of honey against oral bacteria and compare the same with 0.2% chlorhexidine; and 2) to compare antiplaque efficacy in vivo with chlorhexidine. METHODS: The study was conducted in two parts. In the in vitro part, the inhibitory effects of three test agents, 0.2% chlorhexidine gluconate, honey mouthwash, and saline, against six oral bacteria at concentrations of 1, 2, 4, 8, 16, 32, 64, 128, 256, and 512 µg/mL were tested in duplicate. The minimum inhibitory concentration (MIC) was set as the lowest concentration of the agent that completely inhibited the growth of the test species. The in vivo part consisted of a double-masked parallel clinical trial based on a 4-day plaque regrowth model. Sixty-six volunteers, 20 to 24 years of age, participated in the study, and the plaque scores were compared at baseline and at the end of 4 days. The Kruskal-Wallis test was used for significance, and the Mann-Whitney U test was used for pairwise comparison of the groups. The mean plaque scores were 1.77 ± 0.86, 1.64 ± 0.90, and 3.27 ± 0.83 for groups 1, 2, and 3, respectively. RESULTS: The honey mouthrinse effectively inhibited the six tested microorganisms. The chlorhexidine gluconate rinse had the lowest MICs compared with honey and saline rinses for all test species examined. The in vivo results revealed that plaque formation was inhibited/reduced by chlorhexidine and honey rinses. CONCLUSION: Honey has antibacterial action against tested oral microorganisms and also has antiplaque action.

Randomized, controlled, single-masked, clinical study to compare and evaluate the efficacy of microspheres and gel in periodontal pocket therapy.

BACKGROUND: The aim of this randomized, split-mouth, single-masked study is to compare the efficacy of a gel and microspheres as drug-delivery systems in the treatment of periodontal disease. METHODS: Microspheres were prepared, the release patterns of the microspheres and gel formulations were analyzed using an ultraviolet spectrophotometer, and particle shapes were studied under a scanning electron microscope. A split-mouth design was followed in which 30 potential sites were identified and divided into three groups: one control group and two groups in which microspheres or a gel was placed. Patients were recalled at 1, 3, 6, and 9 months. Clinical recordings included plaque index (PI), gingival index (GI), probing depth (PD), and relative attachment level (RAL) measurements; subgingival plaque was also obtained for microbiologic examination prior to and after therapy. RESULTS: Microspheres had a more sustained release and a high initial drug concentration. There was a significant improvement in the PI and GI in the initial 3 months. The results were statistically significant at P = 0.01. The mean PD scores among scores for the three groups at baseline and follow-up visits showed a reduction of 0.4 to 1 mm. The microbiologic parameters were also statistically significant. CONCLUSION: These data suggest that the type of delivery system could significantly influence the outcome of therapy.

Development and evaluation of novel biodegradable microspheres based on poly(d,l-lactide-co-glycolide) and poly(epsilon-caprolactone) for controlled delivery of doxycycline in the treatment of human periodontal pocket: in vitro and in vivo studies.

This study reports on the development of novel biodegradable microspheres prepared by water-in-oil-water (W/O/W) double emulsion technique using the blends of poly(d,l-lactide-co-glycolide) (PLGA) and poly(epsilon-caprolactone) (PCL) in different ratios for the controlled delivery of doxycycline (DXY). Doxycycline encapsulation of up to 24% was achieved within the polymeric microspheres. Blend placebo microspheres, drug-loaded microspheres and pristine DXY were analyzed by Fourier transform infrared spectroscopy (FT-IR), which indicated no interaction between drug and polymers. Differential scanning calorimetry (DSC) on drug-loaded microspheres confirmed the polymorphism of DXY and indicated a molecular level dispersion of DXY in the microspheres. Scanning electron microscopy (SEM) confirmed the spherical nature and smooth surfaces of the microspheres produced. Mean particle size of the microspheres as measured by dynamic laser light scattering method ranged between 90 and 200 mum. In vitro release studies performed in 7.4 pH media indicated the release of DXY from 7 to 11 days, depending upon the blend ratio of the matrix. Up to 11 days, DXY concentrations in the gingival crevicular fluid were higher than the minimum inhibitory concentration of DXY against most of the periodontal pathogens. One of the developed formulations was subjected to in vivo efficacy studies in thirty sites of human periodontal pockets. Significant results were obtained with respect to both microbiological and clinical parameters up to 3 months even as compared to commercial DXY gel. Statistical analyses of the release data and in vivo results were performed using the analysis of variance (ANOVA) method.