Comparison of Salivary Calcium Level in Dentulous and Edentulous Patients

Effect of Calcium Ion Supplementation on Oral Microbial Composition and Biofilm Formation In Vitro

The oral cavity contains a variety of ecological niches with very different environmental conditions that shape biofilm structure and composition. The space between the periodontal tissue and the tooth surface supports a unique anaerobic microenvironment that is bathed in the nutrient-rich gingival crevicular fluid (GCF). During the development of periodontitis, this environment changes and clinical findings reported a sustained level of calcium ion concentration in the GCF collected from the periodontal pockets of periodontitis patients. Here, we report the effect of calcium ion supplementation on human oral microbial biofilm formation and community composition employing an established SHI medium-based in vitro model system. Saliva-derived human microbial biofilms cultured in calcium-supplemented SHI medium (SHICa) exhibited a significant dose-dependent increase in biomass and metabolic activity. The effect of SHICa medium on the microbial community composition was evaluated by 16S rRNA gene sequencing using saliva-derived microbial biofilms from healthy donors and periodontitis subjects. In this study, intracellular microbial genomic DNA (iDNA) and extracellular DNA (eDNA) were analyzed separately at the genus level. Calcium supplementation of SHI medium had a differential impact on iDNA and eDNA in the biofilms derived from healthy individuals compared to those from periodontitis subjects. In particular, the genus-level composition of the eDNA portion was distinct between the different biofilms. This study demonstrated the effect of calcium in a unique microenvironment on oral microbial complex supporting the dynamic transformation and biofilm formation.

Salivary parameters of adults with diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE

Among the oral manifestations of diabetes mellitus (DM), salivary alterations stand out when considering that they can be linked to environmental changes that prompt other oral diseases. This study aimed to compare whether salivary parameters such as salivary flow, ionic composition, pH, and buffer capacity are altered in adults with DM.

STUDY DESIGN

A literature search was performed in 8 databases and the gray literature. Observational and clinical studies with populations >30 years old were included. The methodological quality of individual studies was assessed, 7 meta-analyses were performed, and the certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach (protocol registered at PROSPERO-CRD42021214632).

RESULTS

Of the 5,816 titles retrieved, 22 observational studies were included, representing a total of 1,202 individuals with DM and 946 normoglycemic control subjects. Individuals with DM had significantly lower unstimulated (mean difference [Md] = 0.13 mL/min; CI = 0.06-0.2; P = .0005) and stimulated (Md = 0.44 mL/min; CI = 0.13-0.75; P = .005) salivary flow rates, a lower pH when evaluated with electrodes (Md = 0.45; CI = 0.19-0.71; P = .0007), and a higher salivary urea (standard Md = 1.52; CI = 0.19-2.85; P = .03). No significant differences were found in the other parameters.

CONCLUSIONS

Although the certainty of evidence was low because of the type of studies included, this review indicated salivary alterations in individuals with DM, such as hyposalivation, pH, and urea concentration.