This current study uses the largest survey among existing studies relating to denture adhesives using a web-based survey system. The substantial proportion of denture wearers, which were 1470 persons, were investigated for the use of denture adhesives. As a result, we revealed the utilization of denture adhesives and the factors related to use or non-use of denture adhesives.
Out of the 5935 participants who answered to this web survey, 1470 participants were denture wearers. Among the 1470 participants, 380 participants were complete denture wearers and 1084 participants were partial denture wearers. The number of participants greatly differed by gender. There were 1153 male and 317 female participants. This gender gap was because participants could freely participate and no rule on gender was specifically determined for this study. Previous studies showed that general and oral health literacy and their related factors differed between genders (24, 25) Therefore, in the same way, the related factor to denture adhesive use or non-use is possibly different between genders. Thus, we have to recognize that the gender gap may affect the results of this study. As this study was a web-based survey, it was expected from the survey that there would be a limitation regarding computer-use for older age groups. Therefore, majority of the participants may come from the younger age groups. However, the group of participants was still widely distributed in this study. The median age was 70, while the maximum and minimum age were 89 and 55 respectively. Therefore, an analysis of a wide age group was possible in this particular study.
There were 318 (21.6%) out of 1470 denture adhesives users in this study as shown in Table 2. Coates reported that 6.9% of participants in his study used denture adhesive (22). On the other hand, Polyzois reported that 26% and 20% from Greek and Dutch participants respectively used denture adhesives (23). From the 318 denture adhesives users in this study, 212(66.7%) used cream; 74(23.3%) used home liner; 25(7.9%) used powder; 4(1.3%) used sheet; 3(0.9%) used several types. Cream-type user was the majority with home liner users coming in second. These usage rates of the type of denture adhesives showed the same trend in complete and partial denture wearers as shown in Table 2.
To investigate the difference of usage rate of denture adhesives by gender, the type of denture, last dental visit and smoking, Fisher’s exact probability tests were performed. Thereafter, the type of denture (p<0.001), last dental visit (p<0.001), and smoking (p<0.001) was significant, respectively (Table 3). Therefore, it may be concluded that the usage rate of denture adhesive is higher in complete denture wearers than those of partial denture wearers, those who visited dental clinic within a year than those who did not visit within a year, and smokers than non-smokers. The usage rate of denture adhesives differs greatly between partial denture wearers (12.4%) and complete denture wearers (47.7%). Moreover, multivariate adjusted logistic regression analysis using age, gender, the type of denture, last dental visit, and smoking, revealed that complete denture wearers (OR:6.36 [95%CI 4.80-8.47], p<0.001) and smokers (OR:1.44 [95%CI 1.04-2.00], p=0.03) were significant factors (Table 4). This means that complete denture wearers used denture adhesives about 6.36 times more than partial denture wearers. One of the main effects of denture adhesive is the improvement of retention(26). Needless to say, retentive mechanism is different between complete and partial denture with retention mechanism such as clasps. We considered the related factors of using denture adhesive to be different between complete and partial denture wearers. We then performed analyses of complete and partial denture wearers separately in further statistical analyses.
In complete denture wearers, to investigate the difference of usage rate of denture adhesives by gender, type of denture, last dental visit, and smoking, Fisher’s exact probability tests were performed (Table 3). Moreover, multivariate adjusted logistic regression analysis was also performed (Table 4). Though both tests don't show statistically significant results, the logistic regression showed that female participants had proclivity not to use denture adhesive (OR: 0.5 [95%CI 0.3-1.00], p=0.05)(Table 4). Although there was not enough evidence, males have a probability of using denture adhesive more, which might be caused by confounding factor of some male backgrounds. Further studies are needed to reveal the various related factors in using denture adhesives in complete denture wearers.
Next, we performed statistical analyses only in partial denture wearers. Fisher’s exact probability tests revealed that smokers used denture adhesive more (Table 3). Furthermore, multivariate adjusted logistic regression analysis revealed smoking was a statistically significant factor (OR: 1.72 [95%CI 1.09-2.69], p=0.019). Moreover, smokers used denture adhesive 1.72 times more than non-smoker (Table 4). Smoking can cause reduced salivary flow or dry mouth -- called xerostomia (27). This is one of the reasons why smokers who are partial denture wearers use denture adhesive. Saliva plays an important role for dentures. Stimulated salivary flow rate was significantly related to masticatory performance in Eichner group C denture wearers (28). The other reason for smokers using denture adhesive is alveolar bone resorption. There is an irreversible alveolar bone loss during the progression of periodontal disease. Smoking cigarettes is one of the main risk factors in the development of periodontal disease (29).