Evaluation of salivary ow, level of anxiety, and quality of life among elderly patients rehabilitated with removable prostheses

Background: Complete or partial edentulous patients have diculties performing functional tasks such as eating, chewing, and speaking, and this may affect their quality of life. The successful rehabilitation of these patients depends on emotional and psychosocial factors and on patients’ expectation regarding rehabilitation. Objectives: To examine the effect of complete or partial removable prostheses on quality of life, salivary ow, and anxiety level of wearers. Methods: Total and partial bimaxillary edentulous patients who needed rehabilitation by complete or partial removable prostheses were selected. The quality of life, salivary ow, and level of anxiety of patients were assessed using the following questionnaires: Geriatric Oral Health Assessment Index, Visual Analog Scale for xerostomia, and Anxiety Inventory. The questionnaires were used at three time points: three months before the insertion of the prostheses, at the time of insertion, and three months after the insertion of the prostheses. Results: Our study cohort included more women (62.5%) than men (37.5%), with an average age of 65.25 years. The insertion of removable prostheses signicantly inuenced the quality of life, anxiety level, and salivary ow of its wearers, while decreasing the sensation of xerostomia. Conclusions: It was deduced that the insertion of complete or partial removable prostheses inuences the quality of life, anxiety level, and salivary ow of its wearers.


Salivary ow
The subjective assessments of salivary ow were performed using an analog visual scale that composed of eight questions related to xerostomia, which were answered by the patients. The Visual Analog Scale (VAS) for xerostomia (Appendix 1) was proposed by Pai and Ship [13], and subjectively evaluates two main aspects of salivary ow: dryness of oral mucosa (lips, mouth, tongue, or throat) and impaired oral functions due to the sensation of dry mouth (di culty in swallowing or speaking). Two overall items regarding mouth dryness were analyzed: salivary amount and level of thirst. Patients were instructed to answer each item by marking a vertical line on a 100-millimeter horizontal scale.

Level of anxiety
The level of anxiety of patients was assessed by the State-Trait Anxiety Inventory (STAI) (Appendix 2). State anxiety is characterized by feelings of tension, anxiety, and nervousness, and considered to be transitory. Trait anxiety refers to relatively stable individual differences in proneness to anxiety. The stronger an individual's trait anxiety level, the more likely the experience of elevated states of anxiety during threatening situations. Each scale (State/Trait) is composed of 20 items, measured on a 4-point Likert scale, with scores ranging from 20 (Without anxiety) to 80 (Extreme anxiety) [17,18].

Quality of life
Quality of life was assessed by using the Geriatric Oral Health Assessment Index (GOHAI) 19 (Appendix 3), comprising 12 questions that evaluate whether the older adult has shown some degree of functional, painful, or psychological impairment due to oral health problems in the past three months. The GOHAI was speci cally developed for the elderly population and allows the assessment of an individual's functioning ability in his daily routine and how he perceives his entire well-being, thus improving clinical decision making and ability to provide better oral health care.

Statistical analysis
Statistical analysis was performed using SPSS statistical software, version 24.0 (SPSS Inc., Chicago, USA). Descriptive statistical analyses (including frequency distributions and percentages) were performed on patients' demographic data and responses to all questionnaires. Scores obtained for each question were compared among the three time points using non-parametric tests. A Friedman test was applied to STAI-State, STAI-Trait, and GOHAI results, whereas two-way repeated measures of ANOVA (analysis of variance) were applied to the VAS xerostomia questionnaire, followed by a Tukey test. P values less than 0.05 were considered statistically signi cant.
In addition, Kendal correlation test was used to identify the correlation between the two groups ("complete denture" and "partial removable prosthesis") and STAI-State, STAI-Trait, and GOHAI results.
Pearson correlation test was performed to identify the correlation between the groups and the VAS xerostomia questionnaire. P values less than 0.05 were considered statistically signi cant.

Patient demographics
The demographic characteristics of the treated patients are summarized in Table 1. Our study cohort included more women (62.5%) than men (37.5%), and their average age was 65.25 years (ranging from 60 to 82 years). The "complete denture" group included 35% women and 15% men, and their average age was 66.75 years, while the "partial removable prosthesis" group comprised 27.5% women and 22.5% men, and their average age was 63.75 years.

Assessment Of State Anxiety
Regarding the state anxiety scale, signi cant statistical differences were found in the "complete denture" group for most of the questions, except for questions 4 ("I am regretful") and 14 ("I feel high-strung"). The results remained similar in these questions during all time points analyzed, with a predominance of the "Not at all" response. There was a signi cant decrease in transient anxiety levels in this group. On the other hand, the "partial removable prosthesis" group showed no signi cant statistical differences for most of the questions. However, there were signi cant differences for questions 7 ("I am currently worried about possible misfortunes"), 12 ("I feel nervous"), 14 ("I feel high-strung"), 15 ("I am relaxed"), 16 ("I feel content" "), 17 ("I am worried"), and 20 ("I feel ne") ( Table 2).

Assessment Of Trait Anxiety
The trait anxiety scale revealed statistically signi cant differences in both groups for most of the questions (Table 3). For the "complete denture" group, there were no signi cant differences for questions 3 ("I feel like crying"), 4 ("I wish I could be as happy as others seem to be"), and 14 ("I try to avoid facing a crisis or di culty"). For the "partial removable prosthesis", there were no signi cant differences for questions 4 ("I wish I could be as happy as others seem to be"), 5 ("I am losing opportunities because I cannot make decisions fast"), 9 ("I worry too much about things that do not really matter"), 12 ("I lack self-con dence"), and 18 ("I take disappointments so keenly that I cannot get them out of my mind").   Means followed by a different uppercase letter in the line indicate statistical differences between groups (complete denture and partial removable prosthesis) at each time point analyzed, Tukey test (P < 0.05). Means followed by a different lowercase letter in the line indicate statistical differences at each time point (initial, at time of insertion, three months after insertion) for each group analyzed, Tukey test (P < 0.05).

Evaluation Of Quality Of Life
Page 19/28 The GOHAI 19 results showed that there were signi cant improvements in the quality of life of the "complete denture" group among the time points analyzed. On the other hand, quality of life data remained stable among the time points in the "partial removable prosthesis" group (Table 5).

Cross-analysis Of Data
A correlation was found between both groups for STAI-State, GOHAI, and VAS xerostomia questionnaire, while there was no correlation between the groups for STAI-Trait ( Table 6). The correlation between the groups for STAI-State was positive (P = 0.044), whereas for GOHAI (P = 0.011) and VAS xerostomia questionnaire (P < 0.001), the correlation was negative.

Discussion
The demographic data showed that this study cohort included more women (62.5%) than men (37.5%), and their average age was 65.25 years (ranging from 60 to 82 years). The "complete denture" group included 35% women and 15% men, and their average age was 66.75 years, while the "partial removable prosthesis" group comprised 27.5% women and 22.5% men, and their average age was 63.75 years.
These results corroborate other studies [2,20,21] that have found that most edentulous patients are women with an average age of 65 years.
This study evaluated the salivary ow of elderly patients rehabilitated with complete and partial removable prostheses. Saliva plays an essential role in oral health; it has a buffer effect on the acids, aids in cleaning the oral cavity, contains antibodies, and helps prevent erosions and ulcers of the mucosa [22,23]. When salivary ow decreases, there is an increased risk of patients developing diseases such as candidiasis and prostheses causing discomfort, as compared to patients with normal salivary ow [24].
Xerostomia can be caused by several factors, such as advanced age, anxiety, depression, dysfunctions in salivary glands, Sjögren's syndrome, medications, head and neck radiation, and systemic changes such as diabetes mellitus [25].
In patients who use complete and partial removable prostheses, the mechanical action of saliva is needed to assist in the retention of the prostheses. It has been reported that patients who use complete prostheses and have xerostomia exhibit more severe points of ulceration than patients with normal salivary ow [13]. Therefore, xerostomia and salivary hypofunction may have adverse effects in totally or partially edentulous patients and wearers of prostheses, thus affecting chewing, swallowing, speech, and taste [13][14][15][16][17].
Elderly patients tend to have a prevalence of dry mouth, and this can be explained by their consumption of xerogenic drugs that affect the perception and production of saliva; other causes of dry mouth in elderly patients include autoimmune diseases or radiotherapy in malignant lesions [25]. However, in this study, there was a decrease in the scores of the VAS xerostomia questionnaire in both groups, indicating that patients reported a lower sensation of dry mouth among the time points analyzed.
The xerostomia scores of the two groups remained stable between the initial time point and at the time of insertion, while the feeling of xerostomia decreased three months after insertion (Table 4). This likely occurs because the prostheses are perceived as a foreign body and, thus, more saliva is secreted to promote better lubrication and defense [11,26]. In addition, prostheses cause chronic stimulation of mechanoreceptors, which can increase the salivary re ex through the pressure caused by them. This corroborates the study by Wolff et al. (2004) [11], who observed an increase in patients' salivation after the insertion of conventional complete prostheses.
However, patients with high levels of anxiety may experience decreased salivary ow and, consequently, a sensation of dry mouth [27,28]. The salivary glands have sympathetic and parasympathetic innervation, and both promote salivary secretion. Sympathetic activity is intensi ed by stress, anxiety, and depression.
As a result, there is a decrease in serous salivary secretion, which constitutes the major part of normal total saliva, and an increase in mucous secretion, resulting in a lower volume of ow and an increase in saliva viscosity [28].
State anxiety is a transient emotional condition that consists of consciously perceived feelings of tension, apprehension, and hyperactivity of the autonomous nervous system. State anxiety scores uctuate over time and vary in intensity depending on the perceived danger. Trait anxiety, in turn, presents relatively stable individual differences in the tendency to react to situations perceived as threatening.
Thus, trait anxiety scores are less sensitive to changes arising from environmental situations and remain relatively constant over time [29].
These facts were observed in this study, with state anxiety presenting greater variations over the time points evaluated, while trait anxiety scores remained more constant (Tables 2 and 3). These data corroborate the study by Hashem et al. (2006) [29], which evaluated the anxiety of 18 patients before and after three and six days the placement of dental implants using the STAI and found no statistically signi cant difference in the trait anxiety over the evaluated time points.
Concerning the questionnaire that evaluates state anxiety, there was a decrease in the level of signi cant transient anxiety in the "complete denture" group. Furthermore, anxiety levels and the sensation of hyposalivation also decreased during all assessed time points in both groups. This con rms that psychological factors are associated with hyposalivation and subjective oral dryness, playing a crucial role in the etiology of these conditions. In contrast, anxiety levels among time points remained low in the "partial removable prosthesis" group.
Naumova et al. (2012) [23], evaluated the relationship between stress and salivary secretion, nding no relationship between them; in other words, stress did not reduce salivary ow. However, when evaluating the proteins present in saliva, they observed an increase in their concentration after exposure to stress, leading to the conclusion that the main cause for dry mouth sensation during stressful situations was not the reduction of salivary ow, but the change in saliva composition.
The etiology of anxiety is complex and multifactorial. During prosthetic rehabilitation, the anxiety can be aggravated by feelings of embarrassment and shame, as well as by the possibility that the treatment would not be successful [23]. The psychological impact of this treatment is strongly in uenced by the type of limitation an individual experiences in their quality of life as a consequence of edentulism.
Therefore, patients' satisfaction with this treatment option is of utmost importance during its planning and implementation, as even patients who apparently conform well to dental losses tend to have high expectations from their prostheses [27].
In this study, the rehabilitation of total and partial edentulous elderly patients concerning their quality of life was also assessed with the GOHAI questionnaire. The improvement of patients' quality of life using removable prosthetics is proportional to the satisfaction with rehabilitation, and several factors are considered important for higher patient satisfaction [2]. Speci cally, the "complete denture" group showed a signi cant improvement in their quality of life over the study period.
One of the most serious consequences of edentulism and the use of maladaptive prostheses is social isolation. Edentulism can negatively affect the social life of patients, which can be reduced through rehabilitation with new complete prostheses or implant-retained prostheses [30]. Patients with partial removable dentures do not suffer the full impact of edentulism, and this may be re ected in the results of this study, which showed that in the "partial removable prosthesis" group, quality of life data remained stable over the time points analyzed.

Conclusions
Considering the limitations of this study, and being a pilot study, we can conclude that: -The insertion of complete removable prostheses can signi cantly in uence the quality of life, level of anxiety, and salivary ow of their wearers.
-The insertion of complete and partial removable prostheses decreases the sensation of xerostomia.
-Over the time points evaluated, the feeling of dry mouth was slightly felt by wearers of partial removable prostheses and signi cantly felt by wearers of complete prostheses.
-The sensation of hyposalivation that can be felt by patients with removable prosthetics decreases as the levels of anxiety decrease. Research.

Consent for publication
We informed the patients that the study would be published in an International Journal. The patients were of low income and with little education; therefore, all information about the study was explained in a simpli ed way. The ethics committee approved in Brazil means that the study may use human patients and may be published later.

Availability of data and material
Not applicable.

Competing interests
The authors declare that they have no competing interests.

Funding
Not applicable.
Authors contributions LCB, DMS and CASP participated in the concepts and coordination of the study, drafted the manuscript and performed the study design. NVAM, CLMMN, EVFS and MCG conceived the study, participated in acquisition of data and helped to draft the manuscript. All authors read and approved the nal manuscript.