Monitoring of saliva pH using miniaturized sensing tools as an indicator of oral health

The monitoring of oral disease is important, not alone for oral health, but for the detection and prevention of
systemic disease. The link between oral health and systemic disease is the focus of many studies, with
indications emerging of a causal link [1]. For disease diagnostics, blood has typically been the fluid of choice
for analysis, the retrieval of which is invasive and therefore unsuitable for wearable technology. Analysis of
saliva, however, is less invasive than that of blood, requires little or no pre-treatment and is abundantly
available. A strong correlation has been found between the analytes of blood and saliva [2] with saliva
containing biomarkers for diseases such as diabetes, oral cancer and cardiovascular disease. The development of
an implantable multi-parametric wireless sensor, to monitor both salivary analytes and changes in gingival
temperature, is the aim of this research project.
The aim of our current study is to detect changes in salivary pH, using a gold electrode with a pHsensitive
iridium oxide layer, and an Ion Sensitive Field Effect Transistor probe. Characterisation studies were
carried out in artificial saliva (AS). A salivary pH of between 4.5pH-7.5pH [3], and gingival temperature
between 35°C-38°C [4], were identified as the target range of interest for the human oral environment. Sensor
measurements were recorded in solutions of varying pH and temperature. An ISFET probe was then implanted
into a prototype denture and characterised in AS. This study demonstrates the suitability of ISFET and gold
electrode pH sensors for incorporation into implantable oral sensors.
[1] G. Taylor and W. Borgnakke, “Periodontal disease: associations with diabetes, glycemic control and
complications,” Oral Dis., vol. 14, no. 3, pp. 191–203, Apr. 2008.
[2] E. Tékus, M. Kaj, E. Szabó, N. L. Szénási, I. Kerepesi, M. Figler, R. Gábriel, and M. Wilhelm,
“Comparison of blood and saliva lactate level after maximum intensity exercise,” Acta Biol. Hung., vol. 63
Suppl 1, pp. 89–98, 2012.
[3] S. Naveen, M. L. Asha, G. Shubha, A. Bajoria, and A. Jose, “Salivary Flow Rate, pH and Buffering
Capacity in Pregnant and Non Pregnant Women - A Comparative Study,” JMED Res., pp. 1–8, Feb. 2014.
[4] A. F. Holthuis and F. S. Chebib, “Observations on temperature and temperature patterns of the gingiva. I.
The effect of arch, region and health,” J. Periodontol., vol. 54, no. 10, pp. 624–628, Oct. 1983

Zein-Based Nanoparticles Improve the Oral Bioavailability of Resveratrol and Its Anti-inflammatory Effects in a Mouse Model of Endotoxic Shock

Resveratrol offers pleiotropic health benefits including a reported ability to inhibit lipopolysaccharide (LPS)-induced cytokine production. The aim of this work was to prepare, characterize and evaluate a resveratrol nanoparticulate formulation based on zein. For this purpose, the oral bioavailability of the encapsulated polyphenol as well as its anti-inflammatory effects in a mouse model of endotoxic shock was studied. The resveratrol-loaded nanoparticles displayed a mean size of 307±3 nm, with a negative zeta potential (-51.1±1.55 mV), and a polyphenol loading of 80.2±3.26 μg/mg. In vitro, the release of resveratrol from the nanoparticles was found to be pH independent and adjusted well to the Peppas-Sahlin kinetic model, suggesting a mechanism based on the combination of diffusion and erosion of the nanoparticle matrix. Pharmacokinetic studies demonstrated that zein-based nanoparticles provided high and prolonged plasma levels of the polyphenol for at least 48 h. The oral bioavailability of resveratrol when administered in these nanoparticles increased up to 50% (19.2-fold higher than for the control solution of the polyphenol). Furthermore, nanoparticles administered daily for 7 days at 15 mg/kg, were able to diminish the endotoxic symptoms induced in mice by the intraperitoneal administration of LPS (i.e., hypothermia, piloerection and stillness). In addition, serum TNF-α levels were slightly lower (approximately 15%) than those observed in the control.

Post-diagnostic oral bisphosphonate use and colorectal cancer mortality: a population-based cohort study within the UK Clinical Practice Research Datalink

Background:We conducted the first study to investigate post-diagnostic oral bisphosphonates use and colorectal cancer-specific mortality.

Methods:Colorectal cancer patients were identified from the National Cancer Data Repository (1998–2007) and linked to the UK Clinical Practice Research Datalink, providing prescription records, and Office of National Statistics mortality data. Time-dependent Cox regression models investigated colorectal cancer-specific mortality in post-diagnostic bisphosphonate users.

Results:Overall, in 4791 colorectal cancer patients, there was no evidence of an association between bisphosphonate use and colorectal cancer-specific mortality (adjusted hazard ratio=1.11; 95% confidence interval 0.80, 1.54) or with drug frequency or type.

Conclusions:In this novel population-based cohort study, post-diagnostic bisphosphonate use was not associated with longer rates of colorectal cancer survival.

Relationships between Oral Health and Nutritional Status of Older Adults

Objectives: The World Health Organisation has highlighted the paucity of research into the oral health needs of older adults. In particular, the relationships between oral health and nutritional status require further investigation and analysis. This study aimed to describe some of the relationships between the number of remaining occluding tooth contacts, oral health related quality of life and nutritional status of partially dentate older adults.

Methods: 45 partially dentate patients aged 65 years and older were recruited to the study after visiting a university dental hospital. An initial dental examination charted the remaining teeth including the number of occluding contacts. Oral health related quality of life was recorded using the 14 item Oral Health Impact Profile. Nutritional status was measured using the Mini Nutritional Assessment (MNA) in addition to biochemical analysis of a haematological sample. Correlation between data values was measured using a Pearson's correlation coefficient (r).

Results: The patient sample was made up of 44% males and 56% females with a mean age of 72.4 years (range 65-84 years). With increasing age the patients' oral health related quality of life scores improved. (r=-0.25) Within the sample the number of occluding tooth contacts ranged from 6 to 11. It was found that as the number of occluding contacts increased, better oral health related quality of life scores were recorded. (r=-0.30) Generally mini nutritional assessment scores improved with increasing numbers of tooth contacts. (r=0.14) In addition, as the number of occluding teeth contacts increased total lymphocyte count (r=0.35), vitamin B12 (r=0.22) and serum folate (r=0.06) all increased.

Conclusions: In older patients increased numbers of tooth contacts are associated with better oral health related quality of life. Increasing numbers of occluding contacts are also associated with better MNA scores and some haematological indicators of nutritional status.