A microbiological study of dental calculus.

Abstract

A simple in vitro system has been used to culture 34 species of microorganisms derived from human calculus. A confluent growth on the surface of an agar dise, was subjected to a daily 4 hr incubation in culture medium followed by 20 hr in a metastable solution of calcium phosphate, in a simplified organ culture vessel, for 7–17 days. Smears, taken daily, were stained by Von Kossa's method for the demonstration of calcification. 18 species showed evidence of calcification. In addition to the previously reported Bacterionema matruchotii, Streptococcus salivarius, Streptococcus sanguis (Sherman type 1), Veillonela alcalescens and a Neisseria species, calcification was also demonstrated in Actinomyces naeslundii, 1 strain of Actinomyces viscosus, an unidentified catalase positive facultative Gram‐positive rod, Staphylococcus epidermidis, Micrococcus varians, Eikenella corrodens, a Campylobacter sp., Eubacterium saburreum, an unidentified Gram‐negative rod, Haemophilus aphrophilus, Haemophilus segnis, Bacteroides melaninogenicus and Propionibacterium acnes. The Gram‐negative flore of calculus thus shares with the more frequently studied Gram‐positive species the property of in vitro calcification. Since the surface of calculus is covered with plaque containing a high proportion of Gram‐negative microorganisms, it is suggested that they may play a larger part in the production of calculus than had been indicated previously.

Effect of phosphoproteins on intracellular calcification of bacteria

“…However, some studies have observed intracellular calcification with inorganic calcification solutions [24,25]. Most conventional in vitro experiments use 1.0 mM calcium [6,[23][24][25] or higher concentrations, such as 1.4 mM [20], which is close to that of whole saliva. However, it takes 2 days to 2 weeks to recognize calcification [18][19][20], which may not explain the actual rapidity of dental calculus formation.…”

“…Most conventional in vitro experiments use 1.0 mM calcium [6,[23][24][25] or higher concentrations, such as 1.4 mM [20], which is close to that of whole saliva. However, it takes 2 days to 2 weeks to recognize calcification [18][19][20], which may not explain the actual rapidity of dental calculus formation. Therefore, it is important to consider the calcium concentration of the preferred sites of dental calculus.…”

The effect of chlorhexidine on dental calculus formation: an in vitro study

“…The fact that the pH was neutral between 24 and 48 h may have aided calcification. It has been reported that an alkaline pH in biofilms is critical for the promotion of plaque mineralization [ 20 , 29 ]. In fact, calcium uptake significantly increased after 48 h (four exposures) (Fig.…”

“…After washing with IEW for 1 min, the biofilms were transferred into calcifying solution and incubated for up to 48 h at a maximum of 37 °C under anaerobic conditions (N 2 85%, CO 2 10%, O 2 5%). The calcifying solution was composed of Solution A (NaCl 2.1 g, KCL 1.56 g, Na 2 HPO 4 ·12H 2 O 0.9 g, NaH 2 PO 4 · 2H 2 O 0.39 g, KSCN 0.87 g, Urea 0.2 g, 3,3-dimethylglutaric acid 0.8 g, NaOH 0.36 g, and BHI medium 900 ml) and Solution B (CaCl 2 ·6H 2 O 0.33 g and distilled water 100 ml) [ 20 ]. Solutions A and B were sterilized separately for 20 min at 121 °C and mixed together just before use.…”

Comparative clinical efficacy of three toothpastes in the control of supragingival calculus formation

“…Its porosity can serve as a reservoir for periodontal pathogens and can retain noxious bacterial components such as endotoxin. [45]…”