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 the use or non-use of denture adhesives.
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 [28, 29]. 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 before starting the survey that there would be a limitation regarding computer-use for older age groups. Therefore, the 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 . On the other hand, Polyzois reported that 26% and 20% of Greek and Dutch participants, respectively used denture adhesives . It is not surprising that the usage rate of denture adhesives differs by region or date. As shown in Table 2, 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.
To investigate the difference in usage rate of denture adhesives by gender, the type of denture, last dental visit, and smoking, Fisher’s exact probability tests were performed (Table 3). 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 wearing and smoking were significant factors (Table 4). This means that complete denture wearers used denture adhesives about 6.36 times more than partial denture wearers, and smokers used them about 1.44 times more than non-smokers. Denture type had a particularly powerful influence. One of the main effects of denture adhesive is the improvement of retention . Needless to say, the retentive mechanism is different between complete and partial dentures with retention mechanisms such as clasps. We considered the related factors of using a 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 in 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 do not show statistically significant results, the logistic regression showed that a 95% confidence interval of the odds ratio of female to male was 0.30-1.00. Simply stated, this indicates that female use of denture adhesives is 0.30 to 1.00 times that of male use with a probability of 95%. Although there was not enough evidence, males have a probability of using denture adhesive more, which might be caused by the confounding factor of some male backgrounds. To reveal the various related factors in using denture adhesives in complete denture wearers, further studies are needed that investigate the denture quality and frequency of denture use reported by previous studies .
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 that smoking was a statistically significant factor. Therefore, smokers used denture adhesive about 1.72 times more than non-smoker (Table 4). Smoking can cause reduced salivary flow or dry mouth -- called xerostomia . This is one of the reasons why smokers who are partial denture wearers use denture adhesive. Saliva plays an important role for dentures. The stimulated salivary flow rate was significantly related to masticatory performance in Eichner group C denture wearers .
Moreover, we analyzed related factors for the type of denture adhesive selected. Unfortunately, we did not find significant results, as shown in Tables 5 and 6. Further studies are needed to investigate this subject.
We recognize some limitations in the scope of our study. First, it was sampling bias. This study used a web-based system, and therefore all participants were limited to those who could access the internet. Moreover, the response rate of this study was low because of missing answers. As a result, participants were considered to be independent elderly who had high information literacy skills and did not have severe problems related to activities of daily living. Second, a web-survey system can correct subjective answers of the questionnaire by participants, but cannot correct objective data measured by an examiner, such as objective masticatory performance and denture condition. Taking these limitations into consideration, this is the first study that investigates the utilization of denture adhesive in 1470 denture wearers.
We partially revealed related factors to denture adhesive use. That is to say, in all denture wearers, smokers, and complete denture wearers use more denture adhesive. Moreover, smokers used more denture adhesive if they were partial denture wearers. Therefore, dentists have to see these patients more carefully in consideration of the possibility of the use of denture adhesives and provide appropriate guidance on the effective and appropriate use of denture adhesives. Further studies should be performed to explain the related factors of denture adhesive use in complete denture wearers and the related factors of the type of denture adhesive selection. Moreover, the related factors of denture adhesive use should be examined in greater detail to combine web-survey data with data that was directly examined.