Evidence map›Paper›PMID 41776065›Full record

ArticleClinical oral investigations2026

Morning vs. afternoon saliva: limited diurnal variation in ion composition of unstimulated whole saliva.

Joanita S van Santen, Zainab Assy, Marwa Shanor, Maryam Kazemi, Kamran Nazmi, Henderikus Pots, Sarah Pringle, Floris J Bikker

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Clinical oral investigations, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Joanita S van SantenDepartment of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, Amsterdam, 1081 LA, the Netherlands. j.s.van.santen@acta.nl.ORCID http://orcid.org/0009-0002-7285-7444
Zainab AssyDepartment of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, Amsterdam, 1081 LA, the Netherlands.ORCID http://orcid.org/0000-0002-1531-8930
Marwa ShanorDepartment of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, Amsterdam, 1081 LA, the Netherlands.ORCID http://orcid.org/0009-0002-4814-1606
Maryam KazemiDepartment of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, Amsterdam, 1081 LA, the Netherlands.ORCID http://orcid.org/0009-0002-6270-4655
Kamran NazmiDepartment of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, Amsterdam, 1081 LA, the Netherlands.ORCID http://orcid.org/0000-0001-9868-2959
Henderikus PotsDepartment of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, Amsterdam, 1081 LA, the Netherlands.ORCID http://orcid.org/0009-0006-6639-4278
Sarah PringleDepartment of Rheumatology and Clinical Immunology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, Groningen, 9713 GZ, the Netherlands.ORCID http://orcid.org/0000-0002-0779-1680
Floris J BikkerDepartment of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, Amsterdam, 1081 LA, the Netherlands.ORCID http://orcid.org/0000-0002-9453-4630

Funding

Health-Holland R/011124.03.02
6 · The paper itself

Abstract

objectivesSaliva is increasingly recognized as a valuable diagnostic fluid due to its non-invasive collection and wide range of biochemical markers. However, the potential influence of the circadian rhythm on salivary composition remains a concern, e.g. in clinical diagnostics. This study aimed to determine whether the time of collection—morning (9:00–11:00) versus afternoon (13:00–15:00)—significantly affects ion concentrations in unstimulated whole saliva (UWS). MATERIALS AND

methodsSaliva samples from 30 healthy adults were analyzed for flow rate. Next, cortisol (as a reference marker for the circadian rhythm) and nine salivary ions were quantified using ELISA and capillary electrophoresis, respectively.

resultsNo significant differences were found in flow rate or cortisol levels between the two timepoints. Most ion concentrations, namely sodium, potassium, chloride, phosphate, sulphate, ammonium, and nitrate, also remained stable. In contrast, calcium and magnesium showed significant, opposing shifts: calcium was higher in the afternoon, while magnesium was higher in the morning.

conclusionThese findings suggest that, with some exceptions, salivary ion concentrations are largely unaffected by collection time. CLINICAL RELEVANCE: This supports the flexible use of UWS for diagnostic purposes without strict timing constraints, increasing its applicability in clinical and research settings.

Indexed as

Circadian RhythmIonsSalivaAdultElectrophoresis, CapillaryEnzyme-Linked Immunosorbent AssayFemaleHumansHydrocortisoneMaleTime FactorsHydrocortisoneIonsCircadian rhythmDiagnosticsElectrolytesIonsSaliva

Identifiers

PMID41776065
PMCPMC12957632

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.