Oral dryness, encompassing an individuals’ subjective experience of dry mouth (xerostomia) and objectively measured unstimulated and/or stimulated decreased salivary secretion (hyposalivation), can impair chewing and swallowing and increase the risk of oral diseases, affecting quality of life and well-being. Notably, an individual’s subjective experience of dry mouth does not always align with their salivary secretion rate, suggesting that saliva quality could be of importance. Previous research has examined saliva composition; particularly mucin MUC5B, highlighting the importance of mucin structure for the experience of dry mouth. Findings have been inconsistent, largely because of variations in study populations, saliva and methods used for saliva analysis. This underscores the need for further research. Additionally, earlier studies have explored dentists’ knowledge and clinical management of oral dryness; however, despite its acknowledged clinical relevance, research shows that oral dryness remains an overlooked condition among dental professionals. Research on how dentists and dental hygienists manage oral dryness in dental care in Sweden is limited. Therefore, the overall aim of this thesis was to explore dental professionals’ experiences in managing oral dryness, and to explore associations between xerostomia, clinical signs, salivary secretion rate, and saliva composition in affected individuals. The thesis is based on four studies, where study I is based on a questionnaire, studies II and III are based on semi-structured interviews, and study IV is based on a questionnaire, clinical examinations, and laboratory analyses.

In study I, dentists’ and dental hygienists’ awareness and management of oral dryness were examined, as was the influence of length of professionals’ experience on these aspects. Results showed that older adults were more often asked about their experience of dry mouth than were younger individuals. Dental hygienists encountered individuals with oral dryness more often, asked a larger age span about their experience of dry mouth, measured salivary secretion rate, and provided preventive measures more compared to dentists. Dentists showed greater awareness of saliva function, while dental hygienists showed greater awareness of the causes and complications of oral dryness.

The findings from study I were evaluated, and to some extent confirmed in studies II and III. In study II, dental professionals’ experiences showed that managing oral dryness includes challenges like the heterogeneity of the patient group, barriers to measuring salivary secretion, vague routines, lack of treatment options and a necessity to remain up-to-date of current research; however, dental professionals also applied a patient-centred approach in managing oral dryness, including tailoring questions to the individual, viewing the patient holistically, and engaging in sharing-decision-making. In study III, dentists’ and dental hygienists’ experiences collaborating with physicians showed hindrances to collaboration because of dental subsidy application issues, lack of contact pathways, and perceived limited knowledge among physicians. Dental professionals suggested measures to address these hindrances including taking over responsibility for dental subsidies and calling for physicians to improve the information they give to individuals with oral dryness. Collaboration between dentists and dental hygienists was defined by a resource-optimising approach and by clear roles, with dentists playing a coordinating role and dental hygienists playing the key role in the collaboration.

In study IV, saliva secretion, saliva composition (MUC5B, sialic acid, total protein concentration), clinically assessed oral dryness, and severity of xerostomia were explored and compared between two xerostomia groups with different aetiologies (Sjögren's disease and unspecific dry mouth) and controls. The Sjögren's disease group (n =16) and the unspecific dry mouth group (n =9) had significantly higher sialic acid levels, lower total protein output, and higher clinical oral dryness score (CODS). Xerostomia was more severe in the Sjögren’s disease group compared to the unspecific dry mouth group. Very strong correlation was observed between CODS and both unstimulated and stimulated salivary secretion rates. In the unspecific dry mouth group, the severity of xerostomia showed a very strong correlation with saliva composition (sialic acid, MUC5B, and total protein concentration), whereas moderate correlations were observed between CODS and xerostomia severity, and between CODS and stimulated salivary secretion rate in the Sjögren’s disease group.

This thesis concludes that managing oral dryness in dental care is challenging, but a patient-centred approach may be crucial. The findings indicate that saliva secretion rates, xerostomia severity, saliva composition, and clinically assessed dryness differ across groups with xerostomia of different aetiologies where individuals with Sjögren's disease appear to be more affected. However, further research is needed.

Saliva plays a critical role in oral health, offering protection, aiding in digestion, and facilitating speech and swallowing. This study explores the biochemical composition of human saliva from healthy subjects, including total protein, glycoprotein, and calcium concentrations, in relation to its shear and time-dependent rheological properties. Eleven healthy, nonsmoking subjects were recruited, and salivary secretion rates were measured. Assays were used to determine concentrations of total protein, glycoproteins, and calcium, in addition to rheometry for evaluating the rheological properties of saliva. The results showed that unstimulated saliva, dominated by the mucins MUC5B and MUC7, displayed significantly higher viscosity and pronounced viscoelastic properties compared to stimulated saliva. Rheological analysis revealed saliva to be a viscoelastic material, exhibiting both elastic (solid-like) and viscous (liquid-like) responses. Shear thinning behavior was observed, where viscosity decreased with increasing shear rates, contributing to the fluid's ability to adapt to varying oral conditions. Furthermore, saliva exhibited thixotropy, a time-dependent material behavior characterized by structural breakdown under shear and recovery at rest. Calcium and glycoprotein levels were positively correlated with increased viscoelasticity, particularly with the storage modulus (G '), which reflects the ability of saliva to store elastic energy. These findings highlight the intricate relationship between the biochemical composition of saliva and its rheological properties, specifically its capacity for shear thinning, viscoelastic behavior, and time-dependent recovery, which are vital for its lubrication and protective functions in the oral cavity.

Objective: To describe the experiences of general-practising dental professionals in managing oral dryness. Materials and methods: The purposive selection of dentists and dental hygienists sought to create a cohort with varying years of professional experience, of both genders, and in dissimilar working regions and workplaces for one-on-one semi-structured interviews. Qualitative content analysis was used to identify themes and categories, where themes represented the interpretative aspect and categories, the descriptive aspect. Results: Thirteen informants were interviewed (4 dentists, 9 dental hygienists; of these, 9 worked in the Swedish Public Dental Service; 4, in private dental care). Two themes emerged from the analysis. The first theme, “Challenges in managing oral dryness”, comprised five categories: heterogeneity of the patient group, barriers to measuring salivary secretion, routines perceived as vague, lack of treatment options, and necessity to stay current. The second theme, “A patient-centred approach in managing oral dryness”, had three categories: tailoring questions to the individual, viewing the patient holistically, and sharing decision-making. Conclusion: Managing patients with oral dryness is challenging. The study suggests that a patient-centred approach, based on the individual needs of the patient, is crucial for managing patients with oral dryness in the dental situation. Clinical implications: This study stresses the importance of a patient-centred approach in providing individual support for patients with oral dryness. Dental professionals should query all patients about perceived dry mouth. In cases of positive responses, determination of the salivary secretion rate is essential for a comprehensive diagnosis.

Background: Despite the high prevalence of oral dryness and awareness of its complications, there is limited research on the clinical management of patients with oral dryness in general dental care.

Purpose: To (1) describe and compare awareness among dental care professionals regarding saliva functions, potential causes and complications of oral dryness, and patient management (2) Investigate if the length of professional experience influences these aspects.

Methods: A digital self-administrated survey was sent to 2668 dental care professionals working in the general dental care, Public Dental Service, in Sweden. Twelve dental care professionals reviewed the questionnaire prior to its distribution. The questionnaire comprised 32 questions about patient management, awareness of saliva functions, causes and complications of oral dryness, and self-assessment queries.

Results: The response rate was 18.6% (241 dentists and 257 dental hygienists). Older adults (65+) were asked more often about dry mouth (93.0%) compared to those aged 18-23 years (50.0%) and those under 18 years (24.9%). Dental hygienists encountered individuals with oral dryness more frequently (61.1%) than dentists (48.5%) (p < 0.01), and more often asked individuals in the age groups 18-23 years (p = 0.003), 24-40 years (p = 0.045), and 41-65 years (p = 0.031) about dry mouth. A higher proportion of dental hygienists (88.3%) than dentists (51.0%) had measured salivary secretion rate, (p < 0.001) and more often suggested preventive dental care 3-4 times a year, (42.5% vs. 30.5%) (p < 0.007). Dentists had a higher awareness of saliva functions, while dental hygienists had a higher awareness about causes and complications of oral dryness. Higher proportions of dentists and dental hygienists with over 10 years of professional experience had measured salivary secretion rate (69.1% vs. 95.7%) compared to their counterparts with less than 10 years of professional experience (35.9% vs. 79.5%) (p < 0.001 for both).

Conclusion: Compared to dentists, dental hygienists were more attentive to patients with oral dryness as they encountered these individuals more often, asked more age-groups, suggested frequent preventive measures, and had higher awareness of the causes and complications of oral dryness. Length of professional experience could improve both the management of patients with oral dryness and awareness of its causes, particularly for dental hygienists.

Objectives: to compare saliva proteome of patients before treatment of head and neck cancer and six months post-treatment with controls.

Design: Five dentate patients and five age and gender-matched controls were included. The stimulated salivary secretion rate was determined, and saliva was stored at −80 °C. After thawing, 30 mg of each sample and a reference (aliqouts of all samples) was trypsin digested. The digested peptides were analyzed by mass spectrometry. The relative abundances were transformed to log2 and significant differences determined. Relative abundances of mucins were compared with patient's problems with dry mouth, sticky saliva and swallowing. Data are available via ProteomeXchange with identifier PXD047500.

Results: 966 proteins with ≥2 unique peptides were found. Compared with controls, 30 proteins were found in significantly lower relative abundances and 65 in higher at pre-treatment and 38 proteins in significantly lower relative abundances and 34 proteins in higher post-treatment. Regarding proteins from the salivary glands, a significantly lower relative abundance of Cystatins was detected pre-treatment and significantly lower relative abundances of Cystatin, Cysteine-rich secretory protein 3, Lactoperoxidase, Prolactin-inducible protein and Proline-rich protein 4 post-treatment. No clear relation between relative abundance of mucins and dry mouth, sticky saliva and problems with swallowing was detected.

Conclusion: Decreases in several salivary gland proteins post cancer treatment might lead to a reduced defense against oral disorders. Knowledge about changes in saliva proteins in connection with oral cancer treatment is important for planning dental care for these patients.