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Biomedical subjects

M G Newman

Publications and source records attributed to M G Newman.

At least 73 records · Page 4Linked to original sources
PubMed1989

Effect of 0.12% chlorhexidine on bacterial recolonization following periodontal surgery.

Bacterial plaque accumulation following periodontal surgery has been directly associated with delayed and altered surgical wound healing. Successful antimicrobial treatment following periodontal surgery depends upon the elimination and suppression of wound associated microorganisms. Highly effective antimicrobials should also prevent recolonization of periodontopathogens. In this investigation, the antimicrobial effect of a 0.12% chlorhexidine gluconate mouthrinse (Peridex) on bacterial recolonization after periodontal surgery was determined. A double-blind, randomized, placebo-controlled study was carried out on 40 patients for 6 weeks. Patients with moderate periodontitis (AAP Class III) underwent osseous periodontal flap surgery in one quadrant. Subgingival and marginal plaque samples from the surgery area were taken prior to surgery and 2 and 6 weeks postoperatively. General descriptive bacteriological cultural analysis and assays for specific microbial populations were carried out. During the 6 weeks of mouthrinse use, patients using chlorhexidine had significant reductions over placebo (P less than 0.05) in the number of total Gram-positive facultative cocci, streptococci (85.8%); Gram-positive facultative rods, primarily Actinomyces (91.7%); Capnocytophaga (97.6%) and Gram-negative anaerobic rods (94.5%). Few black pigmented Bacteroides or Actinobacillus actinomycetemcomitans were found prior to surgery or any time postoperatively. In the chlorhexidine group, 6 weeks post surgery, streptococci were the predominant bacterial group in the sampled plaque. Quantitatively, the distribution of bacteria, after 2 and 6 weeks of mouthrinse use, was consistent with a young, less mature plaque. A previous study demonstrated that this plaque was associated with clinical health.

Adult↗
PubMed1989

A study of in vitro attachment of Streptococcus sanguis and Actinomyces viscosus to saliva-treated titanium.

This study examined the initial attachment of Streptococcus sanguis G9-B and Actinomyces viscosus T14V to saliva-treated powdered enamel and titanium surfaces. Using an in vitro adherence model, significantly lower numbers of Actinomyces viscosus T14V bound to the saliva-treated titanium surface when compared to that of the similarly treated enamel. The binding of Streptococcus sanguis G9-B to titanium or enamel did not vary significantly. A comparison of the percentage of cells bound to the titanium surface revealed that S sanguis cells attached in significantly higher numbers when compared to the A viscosus cells.

Actinomyces↗
PubMed1989

[Implantation of collagen coated hydroxyapatite particles. A clinical-histological study in humans].

In this study, histologic behaviour of collagen coated hydroxylapatite particles implanted in human periodontal osseous defects has been analyzed. This material was surgically implanted in four patients, and reentry and block biopsies were carried out 4 and 6 months later. The histologic results demonstrate that this material is well tolerated by surrounding tissues, not eliciting an inflammatory reaction. At four months, the hydroxylapatite particles appear encapsulated by a very cellular connective tissue and at 6 months are found in direct contact with osteoid and mature bone. This material acts as a filler material, being fully biocompatible and stimulating an osseoconductive reaction of the adjacent alveolar bone.

Biocompatible Materials↗
PubMed1988

Periodontal considerations of implants and implant associated microbiota.

The scientific and clinical acceptance of the success of osseointegrated dental implants has been firmly established, but the relationships between clinical observation and periimplant pathogenesis is not well understood. Data and concepts regarding the diagnostic value of traditional periodontal evaluation parameters, such as pocket probing depth, bleeding on probing, attachment loss, gingival and plaque indices, and the amount of attached gingiva are discussed. The microbiologic characterization of plaque associated with various implant systems reveals many similarities and some differences compared to natural teeth. An hypothesis for the "periodontal" etiology of implant failure is proposed. The maintenance of edentulous and partially edentulous patients with implants is discussed.

Dental Implantation, Endosseous↗
PubMed1987

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.

Antibodies, Monoclonal↗
PubMed1986

The presence of bacteria in the oral epithelium in periodontal disease. II. Immunohistochemical identification of bacteria.

Serial histological sections of gingiva obtained from each of six advanced adult periodontitis, two localized juvenile periodontitis and two periodontally healthy patients were used for specific identification of bacteria within the oral epithelium and adjacent connective tissue. Healthy gingival biopsies served as controls. Sections from patients and control biopsies were Gram-stained and also screened with antibacterial sera associated with the peroxidase immunocytochemical technique for specific bacterial identification. The "Pop-off" electron microscopic technique was also used to further demonstrate the bacterial nature of peroxidase-stained material. In addition, the possible correlation between bacteria and areas of possible reduced keratinization was investigated. The results showed that sections of orthokeratinized healthy gingiva did not contain bacteria. Gram-stained sections from diseased sites contained large numbers of bacteria in the oral epithelium and adjacent connective tissue. Bacteroides gingivalis and to a lesser extent Capnocytophaga gingivalis were found in periodontitis, and Actinobacillus actinomycetemcomitans was found in juvenile periodontitis when the immunoperoxidase technique was used. The bacterial nature of peroxidase-stained material was confirmed by the "pop-off" technique. In the disease biopsies, bacterial presence was correlated with areas of reduced amounts of keratin suggesting that the oral epithelium may be a portal of entry for bacteria into gingival tissues.

Actinobacillus↗
PubMed1985

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.

Adolescent↗
PubMed1985

The presence of bacteria within the oral epithelium in periodontal disease. I. A scanning and transmission electron microscopic study.

The presence of bacteria within the gingival oral epithelium and adjacent connective tissue in cases of periodontitis and localized juvenile periodontitis have been described using scanning and transmission electron microscopy. The following bacterial morphotypes were identified: cocci, short rods, filaments and few spirochetes in periodontitis and mainly coccobacillary-shaped bacteria in localized juvenile periodontitis. Also Mycoplasma-like structures were identified in the localized juvenile periodontitis cases. Tunnel-like formations at different depths of the oral epithelium contained higher numbers of bacteria than those seen on the adjacent oral surface. Identification of specific bacteria in the oral epithelium may have important pathogenic and therapeutic implications.

Aggressive Periodontitis↗
PubMed1985

Current concepts of the pathogenesis of periodontal disease. Microbiology emphasis.

A summary of the major highlights of periodontal pathogenesis research with particular emphasis on periodontal microbiology is presented. Bacteriologic specificity, periodontal disease activity, anatomical plaque research, bacterial recolonization and the concept of bacterial succession are discussed. Periodontal immunology, gingival fluid, histopathology as well as clinical research are briefly mentioned as they interrelate with periodontal microbiology.

Adult↗
PubMed1984

Mycoplasma in periodontal disease. Isolation in juvenile periodontitis.

Mycoplasma have been identified in one case of juvenile periodontitis by size, morphology, hemadsorption and cultural techniques. These microorganisms were found on the surface of the tooth, on the surface of pocket epithelium and invading the gingival epithelium and adjacent connective tissue. These observations suggest the need for further studies on the role of Mycoplasma in the pathogenesis of advanced periodontal infections. The role of Mycoplasma in periodontal disease is discussed.

Adolescent↗
PubMed1984

The influence of trauma from occlusion on the bacterial repopulation of periodontal pockets in dogs.

Pockets were surgically created in the two upper external incisors of four beagle dogs, and a copper band adapted to prevent reattachment. After 4 weeks the copper bands were removed, the teeth scaled and root-planed and crowns placed on both experimental teeth in such a way that one of them was forced bucally when the teeth occluded. An orthodontic appliance anchored in bands cemented to the cuspid teeth brought the tooth back to its original position when disclusion occurred. Experimental time was 12 weeks. Clinical indices and bacterial samples for darkfield examination were taken at baseline and weekly thereafter. The dogs were fed a diet that favored plaque accumulation and no oral hygiene was performed. Surgically created pockets initially became populated by cocci (65%-75%) and small amounts of motile bacteria (12%-15%) including 3% to 4% spirochetes. In 4 weeks the percentage of cocci declined steadily (42%-45%) and motile bacteria increased to 37% to 43% with spirochetes representing 24% to 27%. After scaling and root planing, the number of cocci increased again and motile bacteria declined although the baseline values were not reached. This decline persisted for 2 weeks after scaling. Repopulation of the pocket in traumatized and nontraumatized teeth followed the same initial pattern, taking again 5 weeks to return to prescaling levels. No difference was found between traumatized and nontraumatized teeth. Clinical measurements, however, revealed a statistically greater loss of attachment in traumatized teeth as compared with nontraumatized teeth.

Animals↗
PubMed1983

Scanning and transmission electron microscopic study of tissue-invading microorganisms in localized juvenile periodontitis.

This transmission and scanning electron microscope study documents the invasion of microorganisms into the gingiva and along resorbing alveolar bone surfaces in a 15-year-old patient with localized juvenile periodontitis. The invading bacteria were mainly Gram-negative fusiform, coccobacilli and spirochetes. Microorganisms identified as Mycoplasma were also found to invade in some areas. Polymorphonuclear neutrophils (PMNs) were seen in association with the bacteria. The majority of bacteria were covered by PMNs and enclosed by the phagocyte but did not appear to lie within phagosomes. High numbers of PMNs were found in the gingival connective tissue inflammatory infiltrate and in the pocket epithelium. Invasion into the gingiva and alveolar bone by bacteria and Mycoplasma in localized juvenile periodontitis may be importance in the therapy of this infection.

Adolescent↗