Characterization of a Macro- and Micro-Textured Titanium Grade 5 Alloy Surface Obtained by Etching Only without Sandblasting

Our purpose was to physically characterize the surface, and the subsurface, of a macro-and micro-textured titanium grade 5 dental implant surface obtained by etching only, without sandblasting. The topography, surface roughness, as well as the surface structure and subsurface distribution of elements, were determined by scanning electronic microscopy (SEM), non-contact profilometry, X-ray diffraction (XRD), and a concentration profile performed by Auger electron spectroscopy (AES). The hydrogen concentration in the implants was measured; the ability to generate nanostructures when stored in deionized water was also investigated. Under SEM, the surface resembled a sandblasted and etched titanium surface with its typical macro-and micro-texture; roughness was moderate with average roughness (Sa) 1.29 µm. No titanium hydride was found at the implant surface and no enrichment of any alloying element was identified at the surface and subsurface. Hydrogen concentration was 79 ppm, within the normative tolerance (<130 ppm). After storage in water for 6 months, densely packed finger-like nanostructures were observed. The clinical advantage of this textured titanium alloy surface is that it displays the typical macro-and micro-features of a moderately rough sandblasted and etched (SLA) titanium surface without leaving behind any foreign sandblasting material

In vitro Interactions between Streptococcus intermedius and Streptococcus salivarius K12 on a Titanium Cylindrical Surface

Peri-implantitis is a steadily rising disease and is caused by oral bacterial pathogens able to form biofilm on implant surfaces and peri-implant tissues, making antibiotics treatment less effective. The use of commercial probiotics against oral pathogens could serve as an alternative to prevent biofilm formation. Streptococcus intermedius is one of the early colonizers of biofilm formation in dental implants. The aim of this study was to model the interaction between S. intermedius and Streptococcus salivarius strain K12, a probiotic bacterium producing bacteriocins. S. intermedius was co-cultured with S. salivarius K12 in an in vitro model simulating the biofilm formation in a dental implant composed by a titanium cylinder system. Biofilm formation rate was assessed by Real-Time PCR quantification of bacterial count and expression levels of luxS gene, used in response to cell density in the biofilm. Biofilm formation, bacteriocin production, luxS expression patterns were found to be already expressed within the first 12 h. More importantly, S. salivarius K12 was able to counter the biofilm formation in a titanium cylinder under the tested condition. In conclusion, our dental implant model may be useful for exploring probiotic-pathogen interaction to find an alternative to antibiotics for peri-implantitis treatment

Periodontal microbiota of Sardinian children: comparing 200-year-old samples to present-day ones

Introduction: The microrganisms of the human oral cavity include more than 700 species or phenotypes of bacteria. Some “diseases of civilization” are strictly correlated to changes in the microbiome following the food revolution that occurred after WWII. For that reason, a precise recognition of the microbiome profile before and after this period should be useful to determine the health-compatible model of icrobiome. The aim of this study was to compare the microbiome profiles (number of total cells, and pathogen types) of dental samples obtained from two distinct groups of children, a 200-year-old retrieved one and a present one. Methods: Two different groups of samples have been studied. The first group was a set of 50 recent subgingival plaque samples obtained from children of age 2-8 years, 14 males and 36 females. They were enrolled by the Department of Dental Disease Prevention (University of Cagliari, in Sardinia, Italy) during standard dental care procedures. None reported periodontal disease and none had been under antibiotic therapy during the previous 6 months. The second group was an old retrieved group that included 24 teeth from 6 different 6- to 8-year-old crania fragments; they were obtained from a 200-year-old charnel-house located in Villaputzu, a city close to Cagliari. Representative periodontal bacteria have been identified by a previously published real-time PCR procedure (Sokransky et al., 1998) in which P. gingivalis and T. forsythia (red complex), A. Original article 2/5 www.jpnim.com Open Access Journal of Pediatric and Neonatal Individualized Medicine • vol. 6 • n. 1 • 2017 Orrù • Contu • Casula • Demontis • Blus • Szmukler-Moncler • Serreli • Maserati • Steri • Fanos • Coghe • Denotti actinomycetemcomitans (green complex) and F. nucleatum (orange complex) were detected. In addition, the title of each pathogen was expressed as a percentage of the total bacteria (biofilm) in the sample. Results and discussion: The profile of periodontal microbiomes, between recent/ancient samples showed a significant difference relative to Sokransky’s red complex bacteria (p < 0.05). In all analyzed periodontal strains, the pathogenic bacteria P. gingivalis and T. forsythia showed the highest title in the recent group. Conclusions: Our hypothesis is that the transfer of “commensal-pathogen” as an absolute number on the oral biofilm might be linked to the distinct alimentary habits of the two populations. Some diet rich in reducing agents, such as processed meat-based foods, might be able to increase the average number of pathogen anaerobic bacteria in the oral microbiota. The outcome would be an increase of the oral systemic diseases reported with these pathogens. Our data suggest that the ancient Sardinian population was able to control the pathogen oral anaerobic biofilm by some diet rich in antioxidant compounds. Further investigations are required to focus on the genetic profile and the health status of this ancient population but it appears that molecular microbiology might be considered as the “time machine” in oral biology

Functional Foods, a new approach in treatment and prevention of oral infections

Aim Current drug therapies against biofilm-mediated diseases e.g. periodontitis, caries, endodontic infection and peri-implantitis, are reaching their limits due the worrying emergence of bacteria drug resistance. This leads to care failure, decrease of quality life and cost increase. Facing the lack of alternative treatments, scientists are searching after natural compounds to help fighting the above mentioned diseases. To suit this purpose, Pistacia lentiscus, a plant growing in Mediterranean maquis and Lentinula edodes (Shiitake), an edible mushroom were selected. Preliminary studies have showed that extracts of these plants have an inhibitory action against oral pathogens. However, little is known if these substances interact with the biofilm formation in the oral cavity. The aim of the present study was therefore to test the efficacy of these extracts as a modulator of the oral biofilm growth in vitro. Methods Different bacterial species belonging to the Streptococci family were selected because they play a key-role in the formation of biofilm in the oral cavity or in other systemic affections. They were: S. hominis , S. intermedius, S. mitis, S. mutans, S. pyogenes, S. agalatiae, in addition we have used as control an oral probiotic strain S. salivarius K12. Pistacia lentiscus oil (LBO) (Mediflora, Cagliari, Italy) and an aqueous extract of Shiitake (Miconet-Pavia) 1/7 v/v, were studied as functional foods. The bacteria were cultivated in Schaedler broth and grown under 37°C and 5% of CO2 conditions in a particular bioreactor to mimic the oral cavity. The first step was to establish the antibiotic sensitivity expressed in terms of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) following the National Committee for Clinical Laboratory Standard protocols (NCCLS). These quantitative results are useful for predicting in the oral tissues (i.e periodontal pocket), the antimicrobial concentration that must be attained to insure the inhibition or kill the pathogen microbiota. The second step was to evaluate the minimal biofilm inhibitory concentration (MBIC). Each strain was exposed at different concentrations of extract, previously mixed with growth medium from ½ to 1/128, extract/liquid medium . After 4 days of incubation, the biofilm was evaluated by a staining method and expressed as 550 nm of absorbance . Results LBO and Shitake showed a different antimicrobial profile against oral Streptococcus spp. In fact only S. intermedius and S. mitis resulted sensitives to LBO (MIC = 25%, MCB < 50%). Despite by using the Shiitake all tested Streptococci resulted inhibits , MICs from 50% to 12.5 %. Only the probiotic strain S. salivarius was insensitive at these functional extracts . The experiments performed in vitro with a simulating oral biofilm bioreactor, showed that all extracts were able to inhibit the biofilm for all pathogens, except for the probiotic strain. The MBICs were comprised: (i) LBO from 25 to 3.1 % and (ii) Shiitake from 25 to 1.12%. These experiments suggesting a different mechanism of bacterial inhibition between these functional foods . Conclusions This opens new ways on the possible treatments of oral pathologies based on the modulation pathogens/probiotics with subsequent formation of an new physiological oral microbiota. Furthermore, being foods, these substances have limited side-effects and might be considered as potential candidates to support existing no surgical therapie

Periodontal microbiota of Sardinian children: comparing 200-year-old samples to present-day ones

Introduction: The microrganisms of the human oral cavity include more than 700 species or phenotypes of bacteria. Some “diseases of civilization” are strictly correlated to changes in the microbiome following the food revolution that occurred after WWII. For that reason, a precise recognition of the microbiome profile before and after this period should be useful to determine the health-compatible model of microbiome. The aim of this study was to compare the microbiome profiles (number of total cells, and pathogen types) of dental samples obtained from two distinct groups of children, a 200-year-old retrieved one and a present one. Methods: Two different groups of samples have been studied. The first group was a set of 50 recent subgingival plaque samples obtained from children of age 2-8 years, 14 males and 36 females. They were enrolled by the Department of Dental Disease Prevention (University of Cagliari, in Sardinia, Italy) during standard dental care procedures. None reported periodontal disease and none had been under antibiotic therapy during the previous 6 months. The second group was an old retrieved group that included 24 teeth from 6 different 6- to 8-year-old crania fragments; they were obtained from a 200-year-old charnel-house located in Villaputzu, a city close to Cagliari. Representative periodontal bacteria have been identified by a previously published real-time PCR procedure (Sokransky et al., 1998) in which P. gingivalis and T. forsythia (red complex), A. actinomycetemcomitans (green complex) and F. nucleatum (orange complex) were detected. In addition, the title of each pathogen was expressed as a percentage of the total bacteria (biofilm) in the sample. Results and discussion: The profile of periodontal microbiomes, between recent/ancient samples showed a significant difference relative to Sokransky’s red complex bacteria (p < 0.05). In all analyzed periodontal strains, the pathogenic bacteria P. gingivalis and T. forsythia showed the highest title in the recent group. Conclusions: Our hypothesis is that the transfer of “commensal-pathogen” as an absolute number on the oral biofilm might be linked to the distinct alimentary habits of the two populations. Some diet rich in reducing agents, such as processed meat-based foods, might be able to increase the average number of pathogen anaerobic bacteria in the oral microbiota. The outcome would be an increase of the oral systemic diseases reported with these pathogens. Our data suggest that the ancient Sardinian population was able to control the pathogen oral anaerobic biofilm by some diet rich in antioxidant compounds. Further investigations are required to focus on the genetic profile and the health status of this ancient population but it appears that molecular microbiology might be considered as the “time machine” in oral biology