Ana Castillo

Periodontopathogen and Epstein-Barr virus-associated periapical periodontitis may be the source of retrograde infectious peri-implantitis.

BACKGROUND Herpesviral-bacterial synergism may play a role in periodontitis and peri-implantitis etiopathogenesis. Periapical periodontitis (PP) lesions can predict future apical peri-implantitis complications. PURPOSE This pilot study aimed to substantiate herpesviral-bacterial coinfection in symptomatic (SP) and asymptomatic (AP) PP and assess associations with periodontopathogen salivary contamination in patients receiving implants. MATERIALS AND METHODS Polymerase chain reaction (PCR)-based identification was performed on PP granulation tissue (GT) from 33 SP and AP patients and compared with unstimulated whole saliva. Quantitative PCR evaluated Epstein-Barr virus (EBV) and cytomegalovirus copy counts. RESULTS SP GT had higher proportions of periodontopathogens. Symptomatic patients were 3.7 times more likely to be infected with EBV than AP (p = .07; 95% CI: 0.8-16.2). SP were 2.9, 2.1, 3.6, and 1.6 times more likely to be infected with Treponema denticola, Prevotella intermedia, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis, respectively. The odds ratio of EBV infecting PP lesions was two times higher in those positive for the virus in saliva. Saliva Tannerella forsythia-positive patients were 15 times more likely to present this pathogen in PP lesions (p = .038). Saliva EBV-positive individuals were 7 and 3.5 times more likely to yield GT contamination with T. forsythia and T. denticola, respectively. EBV copy counts were significantly higher in SP (p < .01). CONCLUSIONS A causal association between EBV, specific bacterial anaerobic infection, and symptomatic PP is likely. EBV high prevalence underscores the viral etiological importance. Salivary EBV contamination is likely to be associated with viral and bacterial GT infection. Saliva PCR analysis can be a good predictor of GT specific infection and help establish antimicrobial therapy. If confirmed by prospective longitudinal clinical trials, antiviral therapy could possibly benefit SP and nonresponsive to treatment individuals and help prevent potential peri-implant infectious complications.

Bone Microbial Contamination Influences Autogenous Grafting in Sinus Augmentation

BACKGROUND The oral occurrence of putative microbial pathogens in humans has been documented in health and disease. The presence of periodontopathogens in patients with a history of periodontal disease may have a negative impact on bone regeneration. This investigation was conducted to confirm the presence of periodontal pathogens in bone particles harvested intraorally for maxillary sinus augmentation and to assess the clinical and radiographic outcomes 6 to 12 months after bone augmentation. METHODS Culture and polymerase chain reaction (PCR)-based identification were performed by paper-point sampling of intraorally harvested bone particles in a group of 12 maintenance patients undergoing maxillary sinus augmentation. Radiographs were taken to assess and compare bone healing and volume gain at baseline and at 6 to 12 months after augmentation. RESULTS The presence of periodontal pathogens (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans [previously Actinobacillus actinomycetemcomitans], Prevotella intermedia, Tannerella forsythia [previously T. forsythensis], Fusobacterium nucleatum, Parvimonas micra [previously Peptostreptococcus micros or Micromonas micros], Campylobacter rectus, enteric Gram-negative rods, and Dialister pneumosintes) was identified in 10 of 12 patients (83%) by culture, PCR, or both and was associated with greater bone volume loss at 6 months postaugmentation. The PCR-positive triad, P. gingivalis, A. actinomycetemcomitans, and P. intermedia, was associated with pronounced volume loss of the grafted sinus at 6 months. CONCLUSIONS To the best of our knowledge, this is the first study to confirm osseous microbial contamination with major periodontopathogens in individuals undergoing maxillary sinus augmentation with a history of periodontitis. The effect on the grafting outcome translated into bone volume loss in the grafted sinus 6 months postaugmentation. Specific microbial contamination may have an impact on osteogenesis in osseous regeneration.

Periodontopathogen and Epstein-Barr Virus Contamination Affects Transplanted Bone Volume in Sinus Augmentation

BACKGROUND Bone microbial contamination can impair osteogenesis. Human herpesviruses-associated vasculitis can cause vascular damage within the osseous graft and host. This study is conducted to substantiate specific contamination and assess the impact 6 months after sinus augmentation. METHODS Culture- and polymerase chain reaction (PCR)-based identification were done on harvested bone particles and unstimulated whole saliva in a group of 30 patients undergoing maxillary sinus augmentation. Patients were divided into two groups: those with and those without a history of periodontitis. Radiographic evaluation was done to assess and compare bone healing and volume gain at baseline and 6 months post-transplantation. RESULTS Seventeen patients had a history of periodontitis, and 13 did not. Ten showed culture- and PCR-negative results and belonged to the periodontally healthy group. The 17 patients with periodontitis showed culture- or PCR-positive results for the targeted periodontal pathogens. Patients with periodontitis were 2.3 times more likely to have positive salivary Epstein-Barr virus type 1 (EBV-1) than those with no history of periodontitis. The likelihood of having moderate to pronounced bone volume loss 6 months postaugmentation was 7.5 times greater in those patients presenting contamination with ≥3 specific pathogens (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, or Prevotella intermedia) versus those with only one (P <0.05). The odds ratio (OR) of pronounced volume loss was 16.3 times higher in those contaminated with a combination of salivary EBV-1 and ≥3 of the previously mentioned species versus only EBV-1 (P <0.05). Individuals showing positive salivary EBV-1 had bone bacterial contamination associated 57% of the time. The OR of having bone microbial contamination in patients with a history of periodontitis was 37.5 times higher than in individuals without periodontitis. CONCLUSIONS This study confirms contamination of bone, harvested intraorally, with key periodontopathogens in individuals undergoing sinus augmentation. Specific microbial contamination can impair osteogenesis. Saliva may act as a vehicle to transport EBV and other pathogens into the sinus. Increased bone volume loss seems to be associated with the occurrence of specific periodontal anaerobic species, salivary EBV-1, or the combination of both.

Antibacterial activity of four dentin bonding systems

The antibacterial action of bonding systems Gluma 2000, Syntac, Prisma Universal Bond 3, Scotchbond Multipurpose and Prime-Bond was tested against 32 strains of the caries-producing bacteria Streptococcus spp., Lactobacillus spp., Actinomyces spp., Porphyromonas spp. and Clostridium spp. An agar plate diffusion method was used with chlorhexidine as the positive control. Assays were performed in triplicate for each component (primer and adhesive) of the bonding systems. All the adhesives were found to inhibit bacterial growth but with differences in their spectra of action. The sum action of the Scotchbond Multipurpose components were most inhibitory and Prime-Bond was found to be the least effective system.

IT-enabled knowledge ambidexterity and innovation performance in small U.S. firms: The moderator role of social media capability

Abstract This study examines the impact of information technology (IT)-enabled knowledge ambidexterity on innovation performance, and the potential moderator role of social media capability on a sample composed of 100 small U.S. firms. The empirical analysis suggests that IT infrastructure enables the firm to explore new knowledge and exploit existing/new knowledge to innovate more and better. We also find that social media capability has a positive moderator role in this equation: IT infrastructure and social media capabilities work together to enable knowledge ambidexterity.

Evaluation of the Automicrobic System for the identification ofStreptococcus mutans

The performance of the Automicrobic System with the Vitek gram-positive identification card (bioMérieux, France) in identifying strains ofStreptococcus mutans was studied. Of 160 strains assayed, 72.5% were confirmed to beStreptococcus mutans; the remainder were identified as other species of streptococci (Streptococcus bovis, Streptococcus uberis, Streptococcus anginosus, Streptococcus sanguis I and II,Streptococcus intermedius, andStreptococcus constellatus).

In vitro activity of macrolides and lincosamides against oral streptococci: a therapeutic alternative in prophylaxis for infective endocarditis.

Susceptibility to macrolides and lincosamides was tested in a total of 446 strains of oral streptococci belonging to eleven species, all isolated from dental plaque and/or saliva in 1991. Minimum inhibitory concentrations (MIC) were determined by the double serial dilutions method in agar. Clindamycin was the most effective antibiotic against all species tested. The results of nearly all parameters (range, mean, MIC(50), MIC(90)) in all species showed erythromycin to be less effective than josamycin, making the latter antibiotic a possible alternative to erythromycin in prophylaxis for infective endocarditis caused by oral streptococci, not only in patients allergic to penicillin, but also in all patients with low-risk lesions, who will be treated with low-risk dental procedures. In these latter patients, antibiotic prophylaxis may be indicated if, after careful evaluation of the individuals situation, no other alternatives are available.

In vitro immune modulation of polymorphonuclear leukocyte adhesiveness by sodium fluoride.

Abstract. We investigated the influence of sodium fluoride on polymorphonuclear leukocyte (PMN) adhesiveness in a healthy subject with low serum levels of fluoride. The PMN were separated from venous blood, and the percentages of adhered and unadhered cells were determined in vitro in plastic culture plates. The cells were cultured with five different fluoride concentrations ranging from 6.25 10‐2μM to 4.0 μM in the presence and absence of autologous serum.

Action of sodium fluoride on phagocytosis by systemic polymorphonuclear leucocytes

Alterations in phagocytosis appear to be important in the onset and development of periodontitis. We investigated new substances that may be of use in the treatment of periodontitis. In a preliminary study, we tested the effect of sodium fluoride on phagocytosis by circulating polymorphonuclear leucocytes (PMNs) in 10 replicate assays using blood from six healthy subjects. Sodium fluoride was tested at concentrations of 1.0 micron to 4.0 microns against Streptococcus oralis, Streptococcus mutans, Streptococcus sobrinus and Streptococcus sanguis. The phagocytic index against all microorganisms increased significantly at all concentrations of sodium fluoride assayed; this effect was dose dependent. Sodium fluoride appeared to stimulate phagocytosis via two mechanisms: an apparent increase in bacterial susceptibility to phagocytosis, and direct stimulation of phagocytosis by PMNs.