Bacteriologic Status of Periapical Tissue in 150 Cases of Infected Pulpless Teeth

Historical and Contemporary Perspectives on the Microbiological Aspects of Endodontics

The microbiota of the oral cavity plays a significant role in pulpal and periapical diseases. Historically, 100 years ago little was known on microbiota, but after a century of investigations, only now can many of the intimate secrets of microbial growth, expansion, persistence, communal activities, and virulence be revealed. However, with the capabilities of the microbiota for mutation, quorum sensing, and information transference, researchers are hard-pressed to keep up with both the changes and challenges that an amazingly wide range of bacterial species pose for both the scientist and clinician. Fortunately, the development and expansion of a vast array of molecular biological investigative techniques have enabled dentistry and its associated medical fields to attempt to keep pace with the wide and fascinating world of oral microbiology.

Dentigenous infectious foci - a risk factor of infective endocarditis

BACKGROUND

Dentigenous, infectious foci are frequently associated with the development of various diseases. The role of such foci in the evolution of endocarditis still remains unclear. This article presents the concluding results of an interdisciplinary study verifying the influence of dentigenous, infectious foci on the development of infective endocarditis.

MATERIAL/METHODS

The study subjects were 60 adult patients with history of infective endocarditis and coexistent acquired heart disease, along with the presence at least 2 odontogenic infectious foci (ie, 2 or more teeth with gangrenous pulp and periodontitis). The group had earlier been qualified for the procedure of heart valve replacement. Swabs of removed heart valve tissue with inflammatory lesions and blood were then examined microbiologically. Swabs of root canals and their periapical areas, of periodontal pockets, and of heart valves were also collected.

RESULTS

Microbial flora, cultured from intradental foci, blood and heart valves, fully corresponded in 14 patients. This was accompanied in almost all cases by more advanced periodontitis (2nd degree, Scandinavian classification), irrespective of the bacterial co-occurrence mentioned. In the remaining patients, such consistency was not found.

CONCLUSIONS

Among various dentigenous, infectious foci, the intradental foci appear to constitute a risk factor for infective endocarditis.

Identification and antibiotic sensitivity of bacteria isolated from periapical lesions

Periradicular tissues from 28 refractory endodontic cases requiring surgical intervention were submitted for histological diagnosis and microbiological culture. Bacteria isolated from these lesions were identified and then tested for their antibiotic sensitivity to a panel of common antibiotics. The periapical tissue specimens of 22 out of 28 lesions (79%) contained microorganisms. Of the 22 cases showing positive growth cultures, 15 were polymicrobial and 7 were single species isolates. Fifty-three different species were recovered: 29 anaerobes, 19 facultative anaerobes, and 5 aerobes. Microbes were observed under light microscopy in only one case. The most common organisms isolated were Propionibacterium acnes, Staphylococcus epidermidis, Streptococcus intermedius, Wolinella recta, Fusobacterium species, and Clostridium species. Antibiotic susceptibility results showed no clear cut evidence of significant antibiotic resistance among the species tested. The results of this study seem to corroborate earlier studies regarding the microbial population of periapical lesions refractory to nonsurgical endodontics.

The microbiology of periapical granulomas

Of the 16 periapical granulomas studied, 14 (88%) yielded a positive growth when homogenized and cultured. The concentration of colony-forming units per milliliter of the suspension ranged from 10(1.3) to 10(4.0) (mean 10(2.2)). A total of 47 isolates comprising 26 (55%) facultative anaerobes and 21 (45%) strict anaerobes were obtained. The organisms most commonly cultured were Veillonella species (15%), Streptococcus milleri (11%), Streptococcus sanguis (11%), Actinomyces naeslundii (11%), Propionibacterium acnes (11%), and Bacteroides species (10%). Most of the organisms (96%) were sensitive to either amoxicillin, clindamycin, or tetracycline, whereas only 45% were sensitive to metronidazole.

The effect of indomethacin on experimental dental periapical lesions in rats

The role of prostaglandins in the pathogenesis of dental granulomas and associated bone loss was studied by testing the ability of indomethacin, a potent inhibitor of prostaglandin synthesis, to influence bone resorption in experimentally induced dental granulomas. The cusps of maxillary first molar teeth of Sprague-Dawley rats were ground away, exposing the dental pulps to the oral environment. Daily i.p. injections of 0.1 to 0.2 ml of indomethacin (10 mg per kg) dissolved in 95% ethyl alcohol were administered to one group of the rats while the other group received i.p. injections of 0.1 to 0.2 ml of 95% ethyl alcohol. The rats were killed after 6 wk and specimens of the molar teeth and surrounding jaw bone were taken for routine histopathological processing. The specimens from indomethacin-treated rats demonstrated milder inflammatory changes and a significantly lower degree of periapical alveolar bone resorption. These results support the suggestion that prostaglandins are involved in the events leading to bone resorption in dental periapical lesions.

Endotoxic activity in periapical lesions

Thirty tissue samples were examined histologically and classified as being inflamed (apical granulomas) or noninflamed (scars or noninflamed cysts). The samples were then homogenized in pyrogen-free water and treated to remove interfering substances. The presence of endotoxin was then determined by means of the limulus assay; 75 percent of the inflamed tissues were positive for endotoxin, while only 20 percent of the noninflamed tissues contained endotoxin. The presence of endotoxin was thus highly correlated (p = 0.015) with the presence of inflammation in these tissues.

Pathologic study of periapical lesions 1. Periapical granulomas: clinical, histopathologic and immunohistopathologic studies

Seventy periapical granulomas were histopathologically examined. They were divided into four types: exudative, granulomatous, granulo-fibrous, and fibrous types. Clinicopathologically, those having marked lymphocytic infiltration were found more frequently in cases having had endodontic treatment; further, the size of a radiolucent area did not exceed that of the involved tooth crown. In contrast, a predominant plasma cell infiltrate was more frequent in cases with open pulp chambers (no treatment). In those cases, the radiolucent area was larger than the crown. Foci with very large radiolucent areas were often of the exudative type. Epithelial proliferation was more frequent in cases without treatment. These findings indicate that endodontic treatment not only stops invasion of injurious factors but also proliferation of epithelium. Furthermore, in frozen sections of 26 granulomas, IgE-containing cells and IgG and C3 fluorescence in the connective tissue were often observed. It appears that IgE-mediated reaction and antigen-antibody complexes may play a role in periapical pathosis.

Occult dental infection as a cause of fever of obscure origin

Three patients with prolonged unexplained fevers were ultimately found to have deep-seated dental infection. After initial examination failed to elicit symptoms or signs of dental infection, and extensive in-hospital evaluation was nonproductive, dental consultation with roentgenograms provided the diagnosis. All three patients underwent dental extractions with periapical or peridontal debridement; following a brief postoperative febrile period, all three responded with defervescence, without subsequent recurrence of fever. These cases emphasize the importance of periapical and peridontal infection as causes of fever of obscure origin. The pathogenesis, characteristics and bacteriology of periapical abscess are discussed.

Immunopathogenesis of chronic periapical lesions. A review

The pathogenesis of periapical lesions has not been fully elucidated. Currently, the possibility of its being an immunologic phenomenon is receiving much attention. This article presents a review of the literature concerning immunologic reactions which may involve periapical lesions. It appears that antigen-antibody complexes and IgE-mediated reactions can initiate preliminary changes in periapical tissues. It is also likely that delayed hypersensitivity participates in the perpetuation and progression of periapical disease.

A histopathologic, histobacteriologic, and radiographic study of periapical endodontic surgical specimens

Data available on 230 periapical endodontic surgical specimens were studied. It was found that bacteria occurred in the periapical tissue very infrequently. In addition, there was no correlation between the presence of acute inflammatory cells and the presence or absence of pain. Granulomas with epithelium occurred in 61 out of 230 cases, while 14 of these were cysts. Of the 110 cases with radiographic follow-up data, 67 were classified as successful, 40 were uncertain, and 3 were unsuccessful according to a modification of Strindberg's criteria, whereas 107 would have been successes according to the criteria of Bender and Seltzer and their associates. No valid biologic or clinical basis for endodontic therapy as suggested by Bhaskar was found in this material.