Diurnal variation of intraoral pH and temperature

Influence of acute dietary nitrate supplementation timing on nitrate metabolism, central and peripheral blood pressure and exercise tolerance in young men

PURPOSE

Dietary nitrate (NO3-) supplementation can lower systolic blood pressure (SBP) and improve exercise performance. Salivary flow rate (SFR) and pH are key determinants of oral NO3- reduction and purported to peak in the afternoon. We tested the hypotheses that NO3--rich beetroot juice (BR) would increase plasma [nitrite] ([NO2-]), lower SBP and improve exercise performance to a greater extent in the afternoon (AFT) compared to the morning (MORN) and evening (EVE).

METHOD

Twelve males completed six experimental visits in a repeated-measures, crossover design. NO3--depleted beetroot juice (PL) or BR (~ 13 mmol NO3-) were ingested in the MORN, AFT and EVE. SFR and pH, salivary and plasma [NO3-] and [NO2-], brachial SBP and central SBP were measured pre and post supplementation. A severe-intensity exercise tolerance test was completed to determine cycling time to exhaustion (TTE).

RESULTS

There were no between-condition differences in mean SFR or salivary pH. The elevation in plasma [NO2-] after BR ingestion was not different between BR-MORN, BR-AFT and BR-EVE. Brachial SBP was unchanged following BR supplementation in all conditions. Central SBP was reduced in BR-MORN (- 3 ± 4 mmHg), BR-AFT (- 4 ± 3 mmHg), and BR-EVE (- 2 ± 3 mmHg), with no differences between timepoints. TTE was not different between BR and PL at any timepoint.

CONCLUSION

Acute BR supplementation was ineffective at improving TTE and brachial SBP and similarly effective at increasing plasma [NO2-] and lowering central SBP across the day, which may have implications for informing NO3- supplementation strategies.

Radiation-associated changes in saliva composition of head and neck cancer patients: A systematic review

Xerostomia is a common radiation-associated toxicity in patients with head and neck cancer. Although several studies examined the decrease in saliva production due to radiotherapy (RT) and investigated the factors associated with this side effect, little is known about the change in radiation-associated saliva composition. This systematic review is the first to summarize existing data and give an overview of the change in pH/buffer capacity, electrolytes, proteins, enzymes, and mucins due to radiation to the salivary glands. Literature search was performed in PubMed and Embase with 47 articles finally eligible for the review, analyzing the saliva composition at several time points before, during and/or after RT, or comparing findings in irradiated patients to a healthy control group. Overall, RT leads to a substantial decrease in salivary pH and buffer capacity. For sodium, chloride and calcium ion, as well as amylase, an increased concentration or activity during RT was reported in most of the studies, followed by a subsequent decrease either already during RT or after the end of treatment. Different trends have been described for the total protein concentration during and after RT. Lactoferrin, however, increased considerably, especially in the first phase of RT. Mucin 5B (MUC5B) concentrations showed a slight increase during RT and concentrations around baseline values again six months post-radiotherapy.

The influence of oral cavity physiological parameters: temperature, pH, and swelling on the performance of denture adhesives - in vitro study

BACKGROUND

The various physical and chemical conditions within the oral cavity are hypothesized to have a significant influence on the behavior of denture adhesives and therefore the overall comfort of denture wearers. As such, this study aims to understand the influence of oral cavity physiological parameters such as temperature (17 to 52 °C), pH (2, 7, 10), and denture adhesive swelling due to saliva (20-120%) on the behavior of denture adhesives. This study further aims to emphasize the need for a collective approach to modelling the in-situ behavior of denture adhesives.

METHODS

Rheological measurements were carried out using the Super Polygrip Ultra fresh brand denture adhesive cream to evaluate its storage modulus (G´) and loss modulus (G´´) values at a range of physiologically relevant temperatures, pH values, and degrees of swelling, to represent and characterize the wide variety of conditions that occur within the oral cavity.

RESULTS

Rheological data was recorded with respect to variation of temperature, pH, and swelling. Overall, it can be seen that the physiological conditions of the oral cavity have an influence on the rheological properties of the denture adhesive cream. Specifically, our data indicates that the adhesive's mechanical properties are weakly influenced by pH, but do change with respect to the temperature in the oral cavity and the swelling rate of the adhesive.

CONCLUSIONS

Our results suggest that the collective inter-play of the parameters pH, temperature and swelling ratio have an influence on the behavior of the denture adhesive. The results clearly highlight the need for developing a multi-parameter viscoelastic material model to understand the collective influence of physiological parameters on the performance of denture adhesives. Multi-parameter models can also potentially be utilized in numerically simulating denture adhesives using finite element simulations.

Do bioactive materials show greater retention rates in restoring permanent teeth than non-bioactive materials? A systematic review and network meta-analysis of randomized controlled trials

OBJECTIVES

To answer the following research question: does the clinical evaluation of restorations on permanent teeth with bioactive materials show greater retention rates than those with non-bioactive materials?

MATERIALS AND METHODS

A search strategy was used in the following databases: MEDLINE via PubMed, Scopus, Web of Science, LILACS, BBO, Embase, The Cochrane Library, and OpenGrey. Randomized controlled trials (RCTs), with a minimum of 2-year follow-up and evaluating at least one bioactive material in permanent teeth were included. Risk of bias was detected according to the Cochrane Collaboration tool for assessing the risk of bias (RoB 2.0), and network meta-analysis was performed using a random-effects Bayesian-mixed treatment comparison model.

RESULTS

Twenty-seven studies were included. The success of the restorations was assessed using modified USPHS system in 24 studies and the FDI criteria in 3 studies. Network meta-analysis revealed three networks based on restoration preparations. Resin composites were ranked with higher SUCRA values, indicating a greater likelihood of being the preferred treatment for class I, II, and III restorations. In class V, resin-modified glass ionomer cement was ranked with the highest value.

CONCLUSION

Bioactive restorative materials showed similar good clinical performance in terms of retention similarly to conventional resin composites.

CLINICAL SIGNIFICANCE

The findings must be interpreted with caution because many RCT on restorative materials aim to verify the equivalence of new materials over the gold standard material rather than their superiority. The present systematic review also suggests that new RCT with longer follow-up periods are necessary.

Salivary Extracellular Vesicles: Biomarkers and Beyond in Human Diseases

Extracellular vesicles, as bioactive molecules, have been extensively studied. There are abundant studies in the literature on their biogenesis, secretion, structure, and content, and their roles in pathophysiological processes. Extracellular vesicles have been reviewed as biomarkers for use in diagnostic tools. Saliva contains many extracellular vesicles, and compared with other body fluids, it is easier to obtain in a non-invasive way, making its acquisition more easily accepted by patients. In recent years, there have been numerous new studies investigating the role of salivary extracellular vesicles as biomarkers. These studies have significant implications for future clinical diagnosis. Therefore, in this paper, we summarize and review the potential applications of salivary extracellular vesicles as biomarkers, and we also describe their other functions (e.g., hemostasis, innate immune defense) in both oral and non-oral diseases.

Oral micro-electronic platform for temperature and humidity monitoring

Intraoral theranostics, the integration of diagnostics and therapeutics within the oral cavity, is gaining significant traction. This pioneering approach primarily addresses issues like xerostomia (dry mouth), commonly resulting from cancer treatment, with a specific focus on monitoring temperature and humidity. This paper introduces the innovative Intra-Oral Portable Micro-Electronic (IOPM) fluidic theranostic device platform. It leverages conventional dental spoons by incorporating advanced sensors for precise measurements of oral temperature and humidity. Personalization options include a microfluidic chip and a tooth model, enabling targeted delivery of therapeutic agents to optimize treatment outcomes. The electronic control system simplifies the administration of fluid dosages, intelligently adjusted based on real-time oral cavity temperature and humidity readings. Rigorous experimental evaluations validate the platform's precision in delivering fluid volumes at predefined intervals. This platform represents a transformative advancement for individuals contending with oral health challenges such as xerostomia (dry mouth). Furthermore, it has the potential to elevate oral healthcare standards by providing advanced diagnostics and tailored therapeutic solutions, benefiting both patients and dental professionals alike.

Association between salivary characteristics and tooth wear: A systematic review and meta-analysis

OBJECTIVE

Literature was systematically reviewed to identify salivary characteristics and their association with tooth wear.

DATA

A protocol was developed a priori (PROSPERO CRD42022338590). Established systematic review methods were used for screening, data extraction, and synthesis. Risk of bias and the certainty of evidence were assessed using the JBI tools and GRADE, respectively. Direct and indirect association between tooth wear and salivary components and characteristics were assessed.

SOURCES

MEDLINE, Embase, SCOPUS, Web of Science, CINAHL, and additional sources were searched.

STUDY SELECTION

Studies reporting salivary characteristics in patients with tooth wear or models thereof were included. Animal and in-vitro studies and case reports were excluded.

RESULTS

One-hundred eleven studies were included. Qualitative analyses showed a negative association between tooth wear and salivary pH and flow rate in many studies. The higher the study size the higher the chances that an association with pH and flow rate was found. Xerostomia, buffer capacity and salivary consistency/viscosity had also some degree of association with tooth wear in fewer studies. Associations with the 39 salivary components were scarcer. Random effects meta-analyses (7 studies) showed that pH levels in stimulated whole saliva were lower in patient with tooth wear compared to controls (-0.07 [-0.10 to -0.04]). However, there was not enough evidence to establish a quantitative association with flow rate. The general risk of bias was unclear and the certainty of evidence was low or very low. A large diversity of methodologies limited the inclusion of all studies in quantitative synthesis.

CONCLUSION

From all potential risk factors, stimulated whole saliva pH showed a negative association, both quantitatively and qualitatively with tooth wear, indicating potential usefulness of pH monitoring in these patients. Moreover, associations between flow rate and tooth wear were observed qualitatively. However, in both cases the risk of bias was mostly unclear, and the certainty of evidence was low. No causal associations could be observed.

CLINICAL SIGNIFICANCE

Tooth wear is a prevalent condition that may lead to functional or esthetic impairments and pain. Knowing the potential risk factors like salivary pH or flow rate and their dynamics could be relevant during tooth wear monitoring and to intervene accordingly, especially in conditions like gastroesophageal reflux disease.

Effect of the denture adhesive for dry mouth on the retentive force of the experimental palatal plates: a pilot controlled clinical trial

BACKGROUND

A denture adhesive for dry mouth with good cleaning properties has recently been developed. While previous studies on models have shown the effectiveness of denture adhesives in terms of retention and cleanability, no reports have evaluated their effectiveness in the oral cavity. The aim of this study was to compare and investigate the retention and usability of an experimental palatal plate in the dentulous jaw using a denture adhesive for dry mouth, a conventional cream-type denture adhesive, an oral moisturizer, and a denture moisturizer.

METHODS

Ten healthy dentulous participants (mean age 27.2 ± 1.6 years) were included in the study. Palatal plates were fabricated. Four test samples were used: denture adhesive for dry mouth, conventional denture adhesive (cream type), oral moisturizer, and denture moisturizer. The sample was applied to the inner surface of the palatal plates, and the retentive force of the palatal plate was measured every 10 min for 30 min. After the measurements, the study participants were asked to rinse the palatal plate with water and subjectively evaluate the samples used.

RESULTS

The conventional denture adhesive (cream type) showed increased retentive force over time, with the maximum retentive force obtained after 10 min of application. However, its washability was rated second lowest. The denture adhesive for dry mouth showed the highest retentive force immediately after application. Its washability was also good.

CONCLUSIONS

The results suggest that the denture adhesive for dry mouth has reasonable retentive force in the oral cavity and cleaning properties compared to the conventional cream-type denture adhesive.

Pepsin in saliva for the diagnosis of erosive esophagitis post-sleeve gastrectomy: a prospective observational study

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) has become the preferred bariatric procedure in many countries. However, new onset erosive esophagitis (EE) is a major shortcoming. Current recommendation is esophago-gastro-duodenoscopy (EGD) should be performed routinely at 1 year and subsequently every 2-3 years to enable the early detection of Barrett's or esophageal adenocarcinoma. This would put significant strains on resources and costs of bariatric program. Our study assesses the association between and diagnostic value of salivary pepsin concentration and endoscopically proven EE in post-LSG patients as a surrogate for EGD.

METHODS

Twenty patients on routine post-LSG endoscopy between June and September 2022 were recruited for this correlational pilot study. Under supervision, fasting and post-prandial saliva sample was collected and analyzed by Peptest lateral flow device. EGD examinations were performed, and patients completed a validated 25-item QoLRAD questionnaire.

RESULTS

We found a significant correlation between positive endoscopy findings of EE and salivary pepsin concentrations. The normal group had a lower mean fasting pepsin level (13.13 ng/mL ± 18.97) versus the EE-group (90.55 ng/mL ± 81.28, p = 0.009) and lower mean post-prandial pepsin level (30.50 ng/mL ± 57.72) versus the EE-group (135.09 ng/mL ± 130.17, p = 0.02). The predictive probabilities from the binary regression of fasting and post-prandial pepsin concentrations yield AUC of 0.955 ± 0.044 (95% CI 0.868 to 1.000, p < 0.001).

CONCLUSION

Our study distinctively identified salivary pepsin to have excellent sensitivity and negative predictive value in EE, potentially useful to preclude the need for post-LSG EGD in asymptomatic patients with low salivary pepsin.

A review on comparative studies addressing exosome isolation methods from body fluids

Exosomes emerged as valuable sources of disease biomarkers and new therapeutic tools. However, extracellular vesicles isolation with exosome-like characteristics from certain biofluids is still challenging which can limit their potential use in clinical settings. While ultracentrifugation-based procedures are the gold standard for exosome isolation from cell cultures, no unique and standardized method for exosome isolation from distinct body fluids exists. The complexity, specific composition, and physical properties of each biofluid constitute a technical barrier to obtain reproducible and pure exosome preparations, demanding a detailed characterization of both exosome isolation and characterization methods. Moreover, some isolation procedures can affect downstream proteomic or RNA profiling analysis. This review compiles and discussed a set of comparative studies addressing distinct exosome isolation methods from human biofluids, including cerebrospinal fluid, plasma, serum, saliva, and urine, also focusing on body fluid specific challenges, physical properties, and other potential variation sources. This summarized information will facilitate the choice of exosome isolation methods, based on the type of biological samples available, and hopefully encourage the use of exosomes in translational and clinical research.

Continuously Quantifying Oral Chemicals Based on Flexible Hybrid Electronics for Clinical Diagnosis and Pathogenetic Study

Simultaneous monitoring of diverse salivary parameters can reveal underlying mechanisms of intraoral biological processes and offer profound insights into the evolution of oral diseases. However, conventional analytical devices with bulky volumes, rigid formats, and discrete sensing mechanisms deviate from the requirements of continuous biophysiological quantification, resulting in huge difficulty in precise clinical diagnosis and pathogenetic study. Here, we present a flexible hybrid electronic system integrated with functional nanomaterials to continuously sense Ca2+, pH, and temperature for wireless real-time oral health monitoring. The miniaturized system with an island-bridge structure that is designed specifically to fit the teeth is only 0.4 g in weight and 31.5×8.5×1.35 mm3 in dimension, allowing effective integration with customized dental braces and comfort attachment on teeth. Characterization results indicate high sensitivities of 30.3 and 60.6 mV/decade for Ca2+ and pH with low potential drifts. The system has been applied in clinical studies to conduct Ca2+ and pH mappings on carious teeth, biophysiological monitoring for up to 12 h, and outcome evaluation of dental restoration, providing quantitative data to assist in the diagnosis and understanding of oral diseases. Notably, caries risk assessment of 10 human subjects using the flexible system validates the important role of saliva buffering capacity in caries pathogenesis. The proposed flexible system may offer an open platform to carry diverse components to support both clinical diagnosis and treatment as well as fundamental research for oral diseases and induced systemic diseases.

Diurnal Temperature Variation: Addressing Once-Daily Nighttime Fevers in the Era of COVID-19

Pediatric patients with "once-daily" fevers are often referred to pediatric infectious disease specialists for evaluation. Often, these fevers occur at nighttime in the absence of additional symptoms and come to the caregiver's attention after a viral illness. It is crucial for caregivers and providers to be able to define and measure fever accurately when trying to ascertain the true etiology of this clinical picture. Fever education is critical in providing reassurance to parents, and fever diaries should be encouraged. In a well-appearing child without any additional symptoms, at least a percentage of these fevers can be explained by normal diurnal variation of temperature. [Pediatr Ann. 2022;51(5):e202-e205.].

Metal Release and Surface Degradation of Fixed Orthodontic Appliances during the Dental Levelling and Aligning Phase: A 12-Week Study

The purpose of the present study is twofold: (i) to assess the salivary nickel, chromium, and iron concentrations and (ii) to characterize the surface microstructure of the typical commercially available Ni-containing metallic appliances during the first 12-week orthodontic treatment period. A total of 85 unstimulated saliva samples were collected from patients before treatment, after 2 days, and after 1, 4, and 12 weeks. Salivary ion concentrations were determined by inductively coupled plasma optical emission spectroscopy, and data were analyzed with the Statistical Package for Social Sciences (IBM SPSS) software. The recorded mean metal concentrations were in the ranges of 132–175 µg/L for Ni, 171–192 µg/L for Cr, and 826–1023 µg/L for Fe. No statistically significant variations were observed between the different study times, and the null hypothesis (the concentrations of metallic ions in patients’ saliva did not significantly change after the placement of the orthodontic appliances) was accepted (p > 0.05). Mean salivary metallic ions were below toxic levels, and no adverse clinical reactions were registered. The intraoral surface degradation of the fixed components was corroborated by optical microscopy, scanning electron microscopy, and energy dispersive spectrometry. Microstructural analysis after complete orthodontic procedure confirmed different corrosion types, from pitting to biocorrosion.

Salivary pH Effect on Orthodontic Appliances: In Vitro Study of the SS/DLC System

Stainless steels (SS) are the most-used alloys for manufacturing fixed orthodontic appliances due to their attractive set of mechanical properties, biocompatibility, and high corrosion resistance. Nevertheless, during regular orthodontic treatments–taking at least around 2 years–the intraoral environment inevitably degrades these bioalloys, releasing metallic ions into the oral cavity. In the first part of this in vitro study, the corrosion resistance of commercial SS appliances (brackets, tubes, and bands) was evaluated in Fusayama-Meyer artificial saliva at pH values of 2.3 and 6.8 over the course of 30 days. As expected, the results corroborated that salivary pH highly influences corrosion behaviour. Released Ni, Cr, and Fe were within dietary intake values. In the second part, a novel approach for oral corrosion prevention based on the chemical inertness of DLC materials is presented. SS surfaces were functionalized with biocompatible a-C:H-sputtered coatings and submitted to the same experimental conditions. The anticorrosion ability of this system was demonstrated, preventing the pitting corrosion that occurred on the SS substrates. Despite the galvanic coupling effect due to the presence of the Cr-based interlayer, this study enhanced the potential use of the reactive sputter-deposited a-C:H coatings in orthodontics.

WHotLAMP: A simple, inexpensive, and sensitive molecular test for the detection of SARS-CoV-2 in saliva

Despite the development of effective vaccines against SARS-CoV-2, epidemiological control of the virus is still challenging due to slow vaccine rollouts, incomplete vaccine protection to current and emerging variants, and unwillingness to get vaccinated. Therefore, frequent testing of individuals to identify early SARS-CoV-2 infections, contact-tracing and isolation strategies remain crucial to mitigate viral spread. Here, we describe WHotLAMP, a rapid molecular test to detect SARS-CoV-2 in saliva. WHotLAMP is simple to use, highly sensitive (~4 viral particles per microliter of saliva) and specific, as well as inexpensive, making it ideal for frequent screening. Moreover, WHotLAMP does not require toxic chemicals or specialized equipment and thus can be performed in point-of-care settings, and may also be adapted for resource-limited environments or home use. While applied here to SARS-CoV-2, WHotLAMP can be modified to detect other pathogens, making it adaptable for other diagnostic assays, including for use in future outbreaks.

Surveillance of salivary properties of pre-orthodontic patients in relation to age and sex

Saliva plays an important role in masticatory function and protection from dental caries. Although studies have been conducted on saliva properties, their results vary widely depending on population settings. Hence, this study was performed to evaluate the results of saliva properties in individuals who attended their first visit for orthodontic treatment. A total of 619 participants were included (387 females and 232 males; mean age: 14.6 years). We conducted oral examinations and saliva (stimulated) tests and evaluated the saliva flow rate, pH, and buffering capacity, along with bacterial culture. Saliva flow rate, pH, and buffering capacity were significantly higher in males than in females. However, the Streptococcus mutans score was significantly higher in females than in males even though oral hygiene was better in females. Significant positive correlations were found between age and saliva flow rate and S. mutans score. On the contrary, significant negative correlations were found between age and pH and buffering capacity. These results were similar to other studies where the target population was children or teenagers. Saliva properties of patients starting orthodontic treatment were almost the same as in populations of similar ages.

Development of a Dental Implantable Temperature Sensor for Real-Time Diagnosis of Infectious Disease

Implantable sensors capable of real-time measurements are powerful tools to diagnose disease and maintain health by providing continuous or regular biometric monitoring. In this paper, we present a dental implantable temperature sensor that can send early warning signals in real time before the implant fails. Using a microfabrication process on a flexible polyimide film, we successfully fabricated a multi-channel temperature sensor that can be wrapped around a dental implant abutment wing. In addition, the feasibility, durability, and implantability of the sensor were investigated. First, high linearity and repeatability between electrical resistance and temperature confirmed the feasibility of the sensor with a temperature coefficient of resistance (TCR) value of 3.33 × 10^–3/°C between 20 and 100 °C. Second, constant TCR values and robust optical images without damage validated sufficient thermal, chemical, and mechanical durability in the sensor’s performance and structures. Lastly, the elastic response of the sensor’s flexible substrate film to thermal and humidity variations, simulating in the oral environment, suggested its successful long-term implantability. Based on these findings, we have successfully developed a polymer-based flexible temperature sensor for dental implant systems.