Inhibitory Effect of a Novel Bisphosphonate, TRK-530, on Dental Calculus Formation in Rats

Bacteria-mediated resistance of neutrophil extracellular traps to enzymatic degradation drives the formation of dental calculi

Dental calculi can cause gingival bleeding and periodontitis, yet the mechanism underlying the formation of such mineral build-ups, and in particular the role of the local microenvironment, are unclear. Here we show that the formation of dental calculi involves bacteria in local mature biofilms converting the DNA in neutrophil extracellular traps (NETs) from being degradable by the enzyme DNase I to being degradation resistant, promoting the nucleation and growth of apatite. DNase I inhibited NET-induced mineralization in vitro and ex vivo, yet plasma DNases were ineffective at inhibiting ectopic mineralization in the oral cavity in rodents. The topical application of the DNA-intercalating agent chloroquine in rodents fed with a dental calculogenic diet reverted NET DNA to its degradable form, inhibiting the formation of calculi. Our findings may motivate therapeutic strategies for the reduction of the prevalence of the deposition of bacteria-driven calculi in the oral cavity.

Detection, removal and prevention of calculus: Literature Review

Dental plaque is considered to be a major etiological factor in the development of periodontal disease. Accordingly, the elimination of supra- and sub-gingival plaque and calculus is the cornerstone of periodontal therapy. Dental calculus is mineralized plaque; because it is porous, it can absorb various toxic products that can damage the periodontal tissues. Hence, calculus should be accurately detected and thoroughly removed for adequate periodontal therapy. Many techniques have been used to identify and remove calculus deposits present on the root surface. The purpose of this review was to compile the various methods and their advantages for the detection and removal of calculus.

Calcium, vitamin D supplements with or without alendronate and supragingival calculus formation in osteoporotic women: a preliminary study

OBJECTIVES

Long-term calcium intake is related to the formation of urinary stones. Structure and composition of kidney and gallstones are similar to dental calculus. Saliva is the source of calcium for supragingival dental calculus formation. The aim of this preliminary study was to evaluate the possible effects of long-term calcium and vitamin D supplementation with or without alendronate administration on salivary electrolyte concentrations and supragingival calculus formation in osteoporotic women.

METHODS

Thirty-one female patients with osteoporosis for at least 3 years participated in this study. Eighteen women were taking calcium plus vitamin D plus alendronate, while 13 women were taking only calcium plus vitamin D supplements. Eleven systemically healthy women volunteered for the control group. Whole saliva samples were collected from all women before initiation of any periodontal intervention. Plaque index, probing depth, clinical attachment level, bleeding on probing, and calculus index were recorded at six sites/tooth. Salivary concentrations of ionic calcium, potassium, magnesium and sodium were determined by atomic absorption spectrophotometer. Results were evaluated statistically by non-parametric tests.

RESULTS

No significant differences were found in clinical parameters or results of saliva analysis between the study groups (p > 0.05).

CONCLUSION

Within the limits of this preliminary study, it is suggested that long-term calcium and vitamin D supplementation with or without alendronate does not appear to have a significant effect on supragingival calculus formation or saliva total calcium, potassium, magnesium and sodium concentrations. Larger-scale studies investigating the possible effects of various treatment modalities of osteoporosis on supragingival calculus formation are required to better clarify this issue.

Bisphosphonate modulates cementoblast behavior in vitro

BACKGROUND

Cementum formation is deemed to be instrumental for the successful regeneration of periodontal tissues, and thus events and modifiers of cementum formation and mineralization need to be determined. This study aimed to determine whether the bisphosphonate 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) altered the behavior of immortalized cementoblasts (osteocalcin-cementoblasts [OCCM]).

METHODS

OCCM from transgenic mice were exposed to HEBP at concentrations ranging from 0.01 to 10.0 microM. The assays performed included the count of cell number for proliferation, Northern blot analysis for gene expression (up to 10 days for core binding factor alpha-1 [Cbfa1], bone sialoprotein [BSP], osteocalcin [OCN], and osteopontin [OPN], markers for cementoblast/osteoblast maturation/mineralization), von Kossa stain and alizarin red S stain for mineralization, and enzyme assay (p-nitrophenol phosphate cleavage) for alkaline phosphatase (ALP) activity.

RESULTS

Mineral nodule formation was inhibited at the higher doses of HEBP (1.0 and 10.0 microM) only. At early stages (1, 3, and 6 days), gene expression assays revealed only subtle changes in treated cells versus untreated cells, but by day 10, groups treated with lower doses (0.01 and 0.1 microM) were markedly different at the gene expression level. OCN was significantly downregulated (70%) at the lowest dose, with less pronounced effects at higher doses. In concurrence, the master switch gene for osteoblasts, Cbfa1, was also downregulated at the lower doses. Inversely, OPN mRNA was enhanced at the lower doses. ALP activity was not altered by HEBP.

CONCLUSION

Bisphosphonate alters cementoblast function in vitro through the regulation of gene expression and mineral formation.