Michael G. Newman

Guiding Periodontal Pocket Recolonization: a Proof of Concept

The complexity of the periodontal microbiota resembles that of the gastro-intestinal tract, where infectious diseases are treatable via probiotics. In the oropharyngeal region, probiotic or replacement therapies have shown some benefit in the prevention of dental caries, otitis media, and pharyngitis, but their effectiveness in the treatment of periodontitis is unknown. Therefore, this study addressed the hypothesis that the application of selected beneficial bacteria, as an adjunct to scaling and root planing, would inhibit the periodontopathogen recolonization of periodontal pockets. Analysis of the data showed, in a beagle dog model, that when beneficial bacteria were applied in periodontal pockets adjunctively after root planing, subgingival recolonization of periodontopathogens was delayed and reduced, as was the degree of inflammation, at a clinically significant level. The study confirmed the hypothesis and provides a proof of concept for a guided pocket recolonization (GPR) approach in the treatment of periodontitis.

Bacterial Studies of the Papillon-Lefevre Syndrome

Rapid (advanced) destruction of the alveolar bone of the deciduous and permanent dentition is characteristic of the Papillon-Lefevre syndrome (PLS) (GORLIN et al, J Pediat 65:895, 1964). Recently, several microbiologic studies utilizing anaerobic methodology have demonstrated that gram-negative anaerobic rods predominate at the bottom of periodontal lesions in patients diagnosed as having periodontosis and rapid periodontitis, but there are no reports which describe the microbiota associated with periodontal lesions in patients with PLS. A three-year-old male child was diagnosed as having PLS. Marked generalized gingival inflammation, calculus, plaque, and suppuration from deep periodontal pockets were noted. In addition, generalized alveolar bone loss was noted radiographically. A total of seven different sites was sampled for microbiologic studies according to the methods of Newman et al and Socransky et al (J Periodontol Res 12:90-106, 1977). Three plaque samples were taken from apical sites in perio-

Effect of Chinese and Western Antimicrobial Agents on Selected Oral Bacteria

The susceptibility of selected oral bacteria, including suspected periodontopathogens, to a commonly employed Chinese herbal medicine Huang-chin (HC, Scutellaria baicalensis) was tested in vitro. The minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) were determined. HC was also compared with tetracycline, alexidine, and stannous fluoride. HCdecoction, ata concentration of 2%, was bacteriostatic in eight of 11 bacteria tested, but a concentration of 3.13% or greater was required for bactericidal effect. Among the tested bacteria, Bacteroides melaninogenicus ss intermedius was the most sensitive (MIC = 1.57%, MBC = 2%); Actinomyces viscosus was the least sensitive (MIC = 6.25%, MBC 12.5%). Tetracycline, alexidine, and SnF2 were bactericidal in vitro in all bacteria tested at concentrations lower than those used clinically.

The Presence of Bacteria in the Oral Epithelium in Periodontal Disease: III. Correlation with Langerhans Cells

Langerhans cells (LC) are cell types found in the skin and gingiva. LC have immunological functions as phagocytic cells and as antigen-presenting cells for T and B lymphocytes. Sections from biopsies of the gingiva in cases of periodontal disease were found to have increased numbers of LC. These biopsies also contained intragingival bacteria. Serial sections of frozen specimens of human gingiva were prepared for staining. Hematoxylin and eosin were used for tissue survey, the Gram stain for assessment of bacterial invasion, anti-Leu-6 monoclonal antibody associated with peroxidase technique (PAP) to identify LC, antibacterial sera to Bacteroides gingivalis and Actinobacillus actinomycetemcomitans associated with peroxidase to specifically identify these two common periodontopathogenic bacteria. Additional positive identification of bacteria was performed by preparing the same histological section containing gram-stained particles for scanning electron microscope and transmission electron microscope LC confirmation. The results suggest that the increased number of LC seen in diseased sites of oral epithelium containing intragingival microorganisms may be one of the host immune mechanisms to penetration by bacteria.

Clinical Science Oral Colonization and Susceptibility Testing of Pseudomonas aeruginosa Oral Isolates from Cystic Fibrosis Patients

Microbial samples from the oral cavities of cystic fibrosis (C.F.) patients and 20 age-matched normal control subjects were characterized. Mucoid variant Pseudomonas aeruginosa was isolated from the tongue, buccal mucosa, and saliva of C.F. patients only. Analysis of the data suggests that the oral cavity is a potential reservoir for this organism. Aspiration and cross-contamination from this reservoir may be important in perpetuating chronic pulmonary infection in C.F. patients. Susceptibility testing was performed on 20 mucoid variant P. aeruginosa oral isolates obtained from the patients according to standardized broth dilution procedures. The in vitro antimicrobial effects of sodium fluoride, stannous fluoride, and chlorhexidine were measured. Analysis of the data suggests that clinically safe and achievable levels of chlorhexidine and stannous fluoride may be antimicrobial.

Gingival enhancement in fixed prosthodontics. Part I: Clinical findings

This study assessed the efficacy of a 0.12% chlorhexidine gluconate (CHX) rinse on the enhancement and maintenance of gingival health in patients receiving fixed prosthodontic treatment. Thirty patient participants in this examiner blind study were randomly assigned into two groups, one control and another group using CHX 15 ml b.i.d. in addition to normal oral hygiene. The medication was used for 2 weeks prior to crown preparation, 3 weeks during provisional crown placement, and 2 weeks after definitive crown cementation. Plaque and gingivitis indices were measured initially and at the three aforementioned points during the 7-week period. The plaque index for the control group decreased by 0.26 units; CHX decreased by 0.63 units at 7 weeks. The gingival index of the control group decreased by 0.37 units; CHX decreased by 0.87 units. Adjunctive use of chlorhexidine with fixed prosthodontic procedures significantly reduced plaque levels and significantly improved gingival health compared with the control patients. Fixed prosthodontic procedures alone decreased plaque levels and increased gingival health.

The effect of calcified bone matrix on the osteogenic potential of hematopoietic marrow.

Abstract The combination of hematopoietic marrow and calcified autogenous matrix markedly enhances the bone-forming potential of the marrow by inducing the marrow to become osteogenic and by the matrix acting as a nidus for new bone growth. It is believed that, through the use of this combination graft, new surgical procedures for effecting complete osseous repair of large defects with relatively small amounts of graft material can be developed.

Comparative Effectiveness Research in Evidence-Based Dental Practice

Will evidence-based dental practice (EBDP) benefit from the projected new drive for comparative effectiveness research (CER)? Optimists may answer Yes certainly, because CER and EBDP are intertwined, and benefit and feed on each other. Others may be more cautious. Any differences in opinion likely arise because the similarities and the differences between CER and EBDP are not clear cut.

Gingival enhancement in fixed prosthodontics. Part II: Microbiologic findings

This study assessed the changes of the subgingival/marginal microflora during fixed prosthodontic procedures and evaluated the effect of adjunctive rinsing with 0.12% chlorhexidine on the subgingival/marginal microflora during fixed prosthodontic treatment. Thirty patients scheduled for fixed prosthodontics were randomly assigned to either rinsing with 15 ml of tap water b.i.d. (control) or rinsing with 15 ml of 0.12% chlorhexidine gluconate b.i.d. (experimental). Subgingival and marginal plaque was analyzed at baseline, before crown preparation (2 weeks), before crown cementation (5 weeks), and 2 weeks after cementation (7 weeks). The fixed prosthodontic procedures alone altered the subgingival and marginal microbiota toward a more health-associated flora. Adjunctive rinsing twice daily with 0.12% chlorhexidine had a significantly greater effect in reducing putative periodontal pathogens compared with the control regimen. This medication was a useful adjunct to regular oral hygiene during fixed prosthodontic procedures by permitting the establishment and maintenance of a microflora compatible with periodontal health.

The role of infection and anti-infection treatment in regenerative therapy.

Infection associated with regenerative therapy is becoming an increasingly important consideration as the frequency and numbers of regenerative procedures increase. Specific recommendations for antimicrobial treatment associated with membranes, grafts, and implants are presented in the context of establishing general principles of infection management. J Periodontol 1993; 64:1166-1170.