Factors in Dental Bacteremia**From the wards and dental clinic of the Jewish Hospital. Work aided by a grant from the Jewish Hospital Research Fund

Microbiology of odontogenic bacteremia: beyond endocarditis

SUMMARY

The human gingival niche is a unique microbial habitat. In this habitat, biofilm organisms exist in harmony, attached to either enamel or cemental surfaces of the tooth as well as to the crevicular epithelium, subjacent to a rich vascular plexus underneath. Due to this extraordinary anatomical juxtaposition, plaque biofilm bacteria have a ready portal of ingress into the systemic circulation in both health and disease. Yet the frequency, magnitude, and etiology of bacteremias due to oral origin and the consequent end organ infections are not clear and have not recently been evaluated. In this comprehensive review, we address the available literature on triggering events, incidence, and diversity of odontogenic bacteremias. The nature of the infective agents and end organ infections (other than endocarditis) is also described, with an emphasis on the challenge of establishing the link between odontogenic infections and related systemic, focal infections.

Root canal treatment and general health: a review of the literature

REVIEW

The focal infection theory was prominent in the medical literature during the early 1900s and curtailed the progress of endodontics. This theory proposed that microorganisms, or their toxins, arising from a focus of circumscribed infection within a tissue could disseminate systemically, resulting in the initiation or exacerbation of systemic illness or the damage of a distant tissue site. For example, during the focal infection era rheumatoid arthritis (RA) was identified as having a close relationship with dental health. The theory was eventually discredited because there was only anecdotal evidence to support its claims and few scientifically controlled studies. There has been a renewed interest in the influence that foci of infection within the oral tissues may have on general health. Some current research suggests a possible relationship between dental health and cardiovascular disease and published case reports have cited dental sources as causes for several systemic illnesses. Improved laboratory procedures employing sophisticated molecular biological techniques and enhanced culturing techniques have allowed researchers to confirm that bacteria recovered from the peripheral blood during root canal treatment originated in the root canal. It has been suggested that the bacteraemia, or the associated bacterial endotoxins, subsequent to root canal treatment, may cause potential systemic complications. Further research is required, however, using current sampling and laboratory methods from scientifically controlled population groups to determine if a significant relationship between general health and periradicular infection exists.

Mechanisms of tissue damage resulting from the use of oral water irrigation devices

Oral water irrigation devices (WIDs) are widely used for oral physiotherapy in homes and dental clinics throughout the world. A major area of concern in the use of WIDs has been the possibility of injury to the sulcular epithelium and underlying tissue. There are several documented clinical cases of tissue injury with the use of WIDs. The existing WIDs exert excessive pressures on the sulcular epithelium. Although it is known that the high jet impact pressures exerted by the WIDs cause the tissue damage, the underlying damage mechanisms are poorly understood. The damage to the sulcular epithelium and underlying tissue is mediated through several physiological and micromechanical processes and includes, among others, the following damage mechanisms: pressure-induced, diffusion-mediated, deposition of bacteria and toxins into the underlying tissue, damage to the collagen network integrity in the tissue, damage to the blood and lymphatic microcirculation, especially damage to the anchoring filaments attached to the terminal lymphatic wall, and direct mechanical damage due to abnormal shear forces induced by the jet. All these damage processes could lead to tissue necrosis.

Evaluation of oral water irrigation devices

Water irrigation devices (WIDs) are widely used in homes and dental offices across the country for oral hygiene. There have been several reported cases of tissue damage with the use of these devices. In the present investigation, two commercially available oral water irrigation devices were evaluated using bioengineering principles. The flow rates delivered by these devices were measured at different control settings. The exit jet velocities and the jet impact thrust were subsequently calculated. Both of the tested commercial oral water irrigation devices were found to exert abnormally high thrust which could cause serious damage to the sulcular epithelium and the underlying tissues. These pressures are far in excess of the pressure intensity necessary to perform the cleaning action. Moreover, the existing designs using reciprocating pumps are unsafe and are potentially dangerous, particularly with small diameter tips. Low operating pressures and the use of centrifugal pumps are recommended.

The colonization and establishment of invading bacteria in periodontium of ligature-treated immunosuppressed rats

The morphologic features and pattern of bacterial invasion of the periodontal tissue in ligature-induced periodontal defects of immunosuppressed rats were studied. Silk ligatures were placed circumferentially on the maxillary left second molar of 24 Sprague-Dawley rats. The treatment group (14 rats) received Cytoxan (75 mg/kg) the day after ligature placement and at Day 4. The control group (10 rats) received no medication. All animals were sacrificed on Day 8 and the maxillae processed for light and electron microscopy. Only ligated sites in immunosuppressed animals exhibited bacterial invasion. Invading bacteria consisted of microcolonies of Gram-negative and Gram-positive coccoid cells and rods located near the tissue surface. Each microcolony consisted of morphologically homogeneous microorganisms. The deeper sites revealed a diffuse invasion of Gram-negative rods which appeared morphologically similar. Other features associated with invasion were complete destruction of epithelial tissue next to the ligature and the lack of inflammatory cells in the gingival region. These findings, when compared to those of other reports of tissue penetration by bacteria, point to the necessity of differentiating between bacterial invasion of gingival tissues, associated with penetration of tissues by proliferating bacteria, and bacterial translocation, a situation in which bacteria are passively carried into the tissues, for example by mechanical manipulation immediately before or during biopsy taking, or possibly during processing for histology.

The incidence of transient bacteremia during periodontal dressing change

Twenty patients undergoing treatment for periodontal disease and not receiving antibiotics, volunteered to donate blood for culture studies to determine the incidence of transient bateremia during the dressing change and suture removal 1 week after periodontal surgery. Each patient contributed 20 ml of blood prior to the dressing change and an additional 20 ml during suture removal. The samples were cultured both aerobically and anaerobically. Bacteria were demonstrated in five out of 20 postoperative cultures (25%). This incidence approached statistical significance at the 0.05 level using Chi-square analysis with a Yates correction. All species were identified as belonging to the genus streptococcus. None of the blood specimens obtained prior to dressing change exhibited bacterial growth. Although the incidence of bacteremia in this study was not statistically significant at the 0.05 level, it may be clinically significant that five out of 20 patients demonstrated transient bacteremia. Commercial materials and equipment are identified in this report to specify the investigative procedures. Such identification does not imply recommendation or endorsement or that the materials and equipment are necessarily the best available for the purpose. Furthermore, the opinions expressed herein are those of the author and are not to be construed as those of the Army Medical Department.

The non-aerobes of post-extraction bacteremia

SYNOPSIS IN INTERLINGUA

LE NON-AEXOSIOS DE BACTERIEMIA POST EXTRACTION.-Con le objectivo de investigar le rolo de anaerobios in bacteriemia post chirurgia, culturationes sanguinee de ante e post extraction esseva effectuate in 100 patientes. Le culturationes de ante le extraction se provava sterile, sed in 64 casos illos de post le extraction esseva positive. Le lineas isolate esseva 67 lineas aerobie e 88 non-aerobies. Le lineas non-aerobie include 5 organismos strictemente dependente de CO2, 46 anaerobios obligatori, e 37 crescente tanto anaerobiemente como etiam in aere con un contento de 5 pro cento de CO2. Tres aliquots de omne specimen individual esseva incubate in tres differente atmospheras gasose. Le precision del studios esseva promovite additionalmente per le meticulose uso de bottilias anaerobie con bouillon "Liquoid."