Oral dryness in relation to film-forming properties of saliva

Dry mouth, or oral dryness, is a complex and quite commoncondition, reported with a varying prevalence of 10-80 %, expressed as a physiological deficiency with or without perceived dysfunction. This condition can severely affect oral health, oral function andquality of life.This thesis is based on four studies:Study I is a systematic review of the scientific literature and anevaluation of the quality of the evidence for diagnostic methods used to identify oral dryness. The literature included publications during the time period January 1966 to February 2011.Results and conclusions: The database searches resulted in 224 titles and abstracts. A total of 18 original studies were judged relevant and interpreted for this review. When evaluating the included studies witha quality assessment tool for diagnostic accuracy, many of the studiesexhibited shortcomings. The most common shortcomings were that the patient selection criteria were not clearly described and the test or reference methods were not described in sufficient detail. Seven of the included studies presented their results as a percentage of correct diagnoses. The evidence for the efficacy of clinical methods to assess oral dryness is sparse and improved standards for the reporting ofdiagnostic accuracy are needed in order to assure the methodological quality of studies. Furthermore, a global consensus regarding theterminology of oral dryness is needed in order to facilitate diagnostic procedures, choice of treatment and research design. Salivary dysfunction has mainly been described as being related to low salivary flow rate but the correlation between salivary flow rate and symptoms has shown to be weak. This suggests that not onlyquantity as a parameter, but also qualitative parameters of saliva,are needed to be included as factors of importance in evaluatingthe perception of oral dryness. The protective functions of salivaare performed both through and within the bulk liquid phase ofsaliva, but maybe more implicit through saliva components beingdynamically associated as a thin intermediary film on all surfacesexposed in the oral cavity. For instance, examples of qualitativeprotective functions of surface associated saliva would be the film- forming capacity and rheological characteristics of saliva. Today thereis a lack of clinical diagnostic methods that systematically combine individual’s perception of saliva and tests of protective functions of saliva, which in combination may identify individuals at risk andneed of directed preventive regimens.The overall aim of this thesis was to evaluate scientifically reported diagnostic methods in use to identify oral dryness and to exploremethods for clinical monitoring of protective functional characteristicsof salivary films Study II surveyed the occurrence of subjective and objective oraldryness in two populations, one randomly selected group and onedental care-seeking group. The relationship between subjectiveand objective oral dryness to clinical parameters was analyzed and individuals were designated into one of four groups depending onthe occurrence of subjectively described and /or clinically measured oral dryness.Results and conclusions: No association between subjective oraldryness and flow rates of unstimulated and stimulated saliva wasfound in either of the two populations studied. Individuals identified with subjective oral dryness or objective oral dryness presented to a greater extent a history of oral rehabilitation compared to individualswho showed no indications of oral dryness. Results and conclusions: Individuals with subjective oral drynessexhibited lower values for saliva viscosity and elasticity, whencompared to the other groups. Additionally, the amount of salivaassociated to a germanium prism was the lowest measured in thisgroup, even if the total protein concentration was not extremely low. These test results in combination with a moderate decrease in surfacetension after 600 s may be indicative of a lower film forming capacityof saliva from individuals expressing subjective oral dryness

Oral dryness in relation to film-forming properties of saliva

Dry mouth, or oral dryness, is a complex and quite commoncondition, reported with a varying prevalence of 10-80 %, expressed as a physiological deficiency with or without perceived dysfunction. This condition can severely affect oral health, oral function andquality of life.This thesis is based on four studies:Study I is a systematic review of the scientific literature and anevaluation of the quality of the evidence for diagnostic methods used to identify oral dryness. The literature included publications during the time period January 1966 to February 2011.Results and conclusions: The database searches resulted in 224 titles and abstracts. A total of 18 original studies were judged relevant and interpreted for this review. When evaluating the included studies witha quality assessment tool for diagnostic accuracy, many of the studiesexhibited shortcomings. The most common shortcomings were that the patient selection criteria were not clearly described and the test or reference methods were not described in sufficient detail. Seven of the included studies presented their results as a percentage of correct diagnoses. The evidence for the efficacy of clinical methods to assess oral dryness is sparse and improved standards for the reporting ofdiagnostic accuracy are needed in order to assure the methodological quality of studies. Furthermore, a global consensus regarding theterminology of oral dryness is needed in order to facilitate diagnostic procedures, choice of treatment and research design. Salivary dysfunction has mainly been described as being related to low salivary flow rate but the correlation between salivary flow rate and symptoms has shown to be weak. This suggests that not onlyquantity as a parameter, but also qualitative parameters of saliva,are needed to be included as factors of importance in evaluatingthe perception of oral dryness. The protective functions of salivaare performed both through and within the bulk liquid phase ofsaliva, but maybe more implicit through saliva components beingdynamically associated as a thin intermediary film on all surfacesexposed in the oral cavity. For instance, examples of qualitativeprotective functions of surface associated saliva would be the film- forming capacity and rheological characteristics of saliva. Today thereis a lack of clinical diagnostic methods that systematically combine individual’s perception of saliva and tests of protective functions of saliva, which in combination may identify individuals at risk andneed of directed preventive regimens.The overall aim of this thesis was to evaluate scientifically reported diagnostic methods in use to identify oral dryness and to exploremethods for clinical monitoring of protective functional characteristicsof salivary films Study II surveyed the occurrence of subjective and objective oraldryness in two populations, one randomly selected group and onedental care-seeking group. The relationship between subjectiveand objective oral dryness to clinical parameters was analyzed and individuals were designated into one of four groups depending onthe occurrence of subjectively described and /or clinically measured oral dryness.Results and conclusions: No association between subjective oraldryness and flow rates of unstimulated and stimulated saliva wasfound in either of the two populations studied. Individuals identified with subjective oral dryness or objective oral dryness presented to a greater extent a history of oral rehabilitation compared to individualswho showed no indications of oral dryness. Results and conclusions: Individuals with subjective oral drynessexhibited lower values for saliva viscosity and elasticity, whencompared to the other groups. Additionally, the amount of salivaassociated to a germanium prism was the lowest measured in thisgroup, even if the total protein concentration was not extremely low. These test results in combination with a moderate decrease in surfacetension after 600 s may be indicative of a lower film forming capacityof saliva from individuals expressing subjective oral dryness

The effect of laser therapy as an adjunct to non-surgical periodontal treatment in subjects with chronic periodontitis : a systematic review

Background: The objective of this study was to systematically review the evidence on the effectiveness of laser therapy as an adjunct to non-surgical periodontal treatment in adults with chronic periodontitis. Methods: A search was conducted for randomized controlled trials comparing the outcome of periodontitis with laser as an adjunct to scaling and root planing in the treatment of chronic periodontal disease. The electronic databases, PubMed and Cochrane Central Register of Controlled Trials, were used as data sources. Screening, data abstraction, and quality assessment were conducted independently by three reviewers (MK, HJ, and CDL). The primary outcome measures evaluated were changes in clinical attachment level, probing depth, and bleeding on probing. Results: The search resulted in 25 abstracts; four randomized controlled clinical trials were included. Four different laser methods were used; consequently, it was impossible to conduct a quantitative data synthesis leading to a meta-analysis. All studies included a limited number of subjects. Conclusions: No consistent evidence supports the efficacy of laser treatment as an adjunct to non-surgical periodontal treatment in adults with chronic periodontitis. More randomized controlled clinical trials are needed. PMID: 18980508 [PubMed - in process

Viscoelastic properties of saliva from different glands

The viscoelastic properties of saliva from different glands were characterized using small amplitude oscillatory shear with a narrow gap parallel plate system. Mechanical spectra of stimulated and unstimulated human submandibular-sublingual saliva (HSMSL) and human parotid saliva (HPS) were compared. The HSMSL saliva had higher modulus and longer relaxation times due to higher mucus content than the parotid saliva. Unstimulated saliva showed the same behaviour when compared to stimulated saliva, but only after aresting period of 20 minutes

Viscoelastic properties of saliva from different glands

The viscoelastic properties of saliva from different glands were characterized using small amplitude oscillatory shear with a narrow gap parallel plate system. Mechanical spectra of stimulated and unstimulated human submandibular-sublingual saliva (HSMSL) and human parotid saliva (HPS) were compared. The HSMSL saliva had higher modulus and longer relaxation times due to higher mucus content than the parotid saliva. Unstimulated saliva showed the same behaviour when compared to stimulated saliva, but only after aresting period of 20 minutes

Delmopinol - adsorption to and absorption through the oral mucosa

The findings indicate that delmopinol interacts with the salivary film of the upper labial mucosa and affects its polarity. It appears that delmopinol assists in the maintenance of the hydrophilicity of the mucosal pellicle and thereby also reinforcing hydration of the mucosa. The rat autoradiograms, showed that radioactivity remains in the oral mucosa after 24 h, but diffuses through the mucosal membranes into the systemic circulation

The Challenge of Measuring Viscoelastic Properties of Human Whole Saliva to Fit Clinical Purpose

To understand the protective functions of saliva secreted from different glands in the masticatory process, it is of interest to study its viscoelastic properties. Characterization of saliva samples are not that easily performed in a clinical setting, since most of the experimental techniques and instruments available are developed for research purposes. The aim of this study was to characterize how the viscoelastic properties of saliva can be measured and monitored using two laboratory instruments. Unstimulated whole saliva from 11 healthy volunteers was characterized using two instruments, an ARES-G2 rheometer and a Bohlin Oscillating Cup Rheometer. Measurements performed on unstimulated human whole saliva showed that the ARES rheometer will in linear viscoelastic conditions of the sample give absolute viscoelastic numbers of undisturbed saliva whilst the BOCR can be used to give an indication of gel strength, gel formation, and gel stability in viscoelastic samples being sheared in their non-linear viscoelastic region by introducing a Saliva Gel Strength Index, SGSI. Both methods clearly illustrate the presence of viscoelastic properties in saliva

Characterisation of Structures in Salivary Secretion Film Forma-tion. An Experimental Study with Atomic Force Microscopy

The purpose of the present study was to characterise the structure dynamics of pure salivary secretions retained on controlled surfaces with different surface energies in the early stage of salivary film formation. Germanium prisms prepared to have either low surface energy of medium surface energy were incubated in fresh secretions of either human parotid saliva (HPS) or human submandibular/sublingual saliva (HSMSLS) for 15,90 and 180 min. After controlled rinsing with distilled water, the surfaces were air dried and thereafter imaged with atomic force microscopy (AFM). The amount of adsorbed material and the size of the structures detected increased with increased saliva exposure time. the film thicknesses varied from 10 to 160 nm, and both HPS and HSMSLS films contained structures with diameters varying from 40 nm to 2 microm. Some of these were clustered into special formations. The HPS films exhibited a more granular morphology than the HSMSLS films. Furthermore, branched lines were detected on the low surface energy germanium prisms incubated in saliva. the results indicate that exposure time, surface energy, and type of salivary secretion all are factors affecting the adsorption characteristics of salivary films