Calcification of oral bacteria: an ultra structural study of two strains of Bacterionema matruchotii

Abstract

– The purpose of this study was to test the hypothesis that the pattern of calcification of dental plaque — either intracellularly or extracellularly — is dependent on the type of microorganisms present. Two strains of Bacterionema matruchotii. Strain 13 (Richardson) and Strain 14266 ATCC, were grown in an in vitro system and their calcification studied by transmission electron microscopy. Mineral crystals appeared in the specimens in scattered areas after 2 weeks of incubation, but consistently and in significant amounts after 4 weeks. In Strain 13 the crystals occurred only intracellularly, while in Strain 14266 the crystals were seen both within and around the bacteria. In the Strain 14266 specimens the extracellular crystals were often related to trilaminar vesicles and cell remnants. Differences in potential of calcification between closely related bacterial strains may partly explain the differences observed between calculus formers and non‐formers.

Observations of the surface of dental calculus using scanning electron microscopy.

“…There was a space that remained uncalcified between the calcified bacteria and the calcified matter around them as shown in Fig. 3, and it is considered to be a part of the cell wall in filamentous bacteria as observed with a transmission electron microscope [20]. The structure of calcified bacteria in carious dentin observed by KOMURO [21] is the same as this.…”

“…Rizzo et al [22] and TAKAZOE et al [23] reported that formalin-killed bacteria calcified faster than living bacteria. LIE et al [20] observed the calcification of Bacterionema matruchotii in vitro with a transmission electron microscope and found intracellular and extracellular calcifications. It is considered that calcification varies depending on the condition and the species of bacteria.…”

Calcification of a Cariogenic Streptococcus and of Corynebacterium (Bacterionema) matruchotii

“…Heavily-, lightly-, and non-calcified cells were observed. Widely varying calcification patterns and morphologies were also noted by Smith et al (1973), Lie andSelvig( 1974), Streckfuss et al (1974), and Sidaway (1980). In addition, the percentage ofcalcified cells (as seen in our TEM preparations) did not relate to the bulk calcium concentration of the sample.…”

“…Intracellular calcium uptake, as opposed to extracellular calcium phosphate formation, may not necessarily relate to calculus production in vivo (Scheie, 1989). However, when methods are used that seem to preserve the interbacterial matrix of calcifying cultures, several C. matruchotii strains, including ATCC 14266, some streptococci, and various Gram-negative bacteria seem to form intra-as well as extracellular mineral deposits (Lie and Selvig, 1974;Streckfuss et al, 1974;Sidaway, 1980). These bacteria may all play a role in calculus formation.…”

“…Both strains are known to calcify readily in several media. The type strain 14266 has been studied in detail (Ennever et al, 1972;Lie and Selvig, 1974;Boyan-Salyers and Boskey, 1980;Ooi et al, 1981; weeks Fig. 1-Calcium in water-washed centrifuged wet bacterial cells harvested from growth on E-agar.…”