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CompletedNCT02587676Updated Dec 28, 2016

Deterioration of Resilient Denture Liners and Patient Characteristics

An observational study in Xerostomia, Menopause and Kidney Disease, sponsored by Nihon University. Completed. Open to participants aged 40 Years to 95 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2016-12-28.

Sponsored by Nihon University · Observational

Study type
Observational
Enrollment
100
Ages
40 Years to 95 Years
Sex
All
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Study summary

Thirty complete maxillary denture wearers were recruited after obtaining informed consent. One investigator measured the Shore D hardness of the commercially available RDLs using a Vesmeter®. The salivary flow rates and pH values and the occlusal force were measured for all patients before initiation of the study.

T-tests and Pearson's correlation coefficients were used for statistical analyses.

A p-value of \<0.05 was considered statistically significant.

Read the detailed description
  1. Participants This study was approved by the Human Ethics Committee of Nihon University School of Dentistry, Matsudo (EC 13-006). Thirty wearers of complete maxillary dentures (12 men; mean age, 71.8 ± 9.2 years and 18 women; mean age, 70.2 ± 10.7 years) who visited the Department of Removable Prosthodontics at our institute were recruited for this study. The volunteers were enrolled only after they provided written informed consent. Complete maxillary denture wearers who had been treated with a tissue conditioner, RDLs, and denture adhesives were excluded. Before starting the clinical trial, the participants were asked about the following environmental factors in a questionnaire: smoking, drinking, denture wearing during sleeping, and denture cleanser usage.

    After specimen making, all participants were instructed to wear their dentures as per their normal routine.

  2. Specimen Preparation A cylinder shapes six places with a 4-mm diameter and 2-mm depth , that was drilled into the inner surface of the denture base. Then, the RDL materials were mixed by each product, packed into the cavity, and polymerized at room temperature . The six commercial RDLs used in this study:Evatouch Super (EVA; Neo Dental Chemical products, Washington, USA), GC RELINE (GCR; GC Dental Products Corp, Tokyo, Japan), Mucopren soft (MCP; Kettenbach GmbH \& Co KG, California, USA) Soften (SFT; KAMEMIZU CHEM, Osaka, Japan), FD Soft (FDS; KAMEMIZU CHEM, Osaka, Japan), and Bio Liner (BIO; Nissin Dental Products, Kyoto, Japan).

    Hardness was measured using a Vesmeter® (WaveCyber Corp, Saitama, Japan). When the probe, which included a built-in position sensor connected to a personal computer, was placed in a perpendicular orientation to an RDL, the indenter of the probe was depressed onto the RDL at a constant speed through electromagnetic power. Simultaneously, the path of the indenter was constantly traced by the position sensor. The computer processed electrical signals from the measuring device and calculated the Shore D hardness, which was the primary outcome in the present study. The same investigator measured the hardness at each appointment. The original hardness and the hardness at 1 month after oral exposure were used for analysis. Each specimen was measured five times, and the highest and lowest values were eliminated from the calculation of the mean representative value for each specimen. The specimens embedded in the dentures were measured on a hot plate to maintain the temperature at 37°C or as close to the oral temperature as possible.

  3. Statistical Analyses Before other statistical analyses, the normality of the data was tested using the Kolmogorov - Smirnov test, and then parametric statistical methods were applied.Two-way repeated measures analysis of variance ( ANOVA ) with the material type (EVA, MCP, GCR, FDS, SFT, and BIO) and time period (baseline and one month after) as factors was used to assess changes in the hardness of the six RDLs over time. The Tukey-Kramer test was used as a post hoc test after the two-way repeated measures ANOVA .The effects of categorical variables such as sex, smoking, drinking, denture wearing during sleeping, and denture cleanser usage on the hardness of the RDLs were analyzed using a two-way ANOVA without a post hoc test; we were not interested in comparing each RDL but rather in analyzing the effects of categorical variables on the RDLs. The effects of continuous variables, including age, salivary flow rate, and occlusal force, were analyzed using Pearson's correlation coefficients. All statistical analyses were performed using IBM® SPSS® Statistics 21 (IBM, Armonk, NY, USA). A p-value of \<0.05 was considered statistically significant.
02

Conditions studied

  • Xerostomia
  • Menopause
  • Kidney Disease
03

In context

Xerostomia

254 studies on the registry are indexed under Xerostomia; 47 are open to participants now.

This study's enrollment of 100 is close to the median of 100 across 31 observational studies indexed under Xerostomia.

Browse Xerostomia studies →

Lead sponsor

Nihon University is the lead sponsor of 13 studies on the registry; none are open to participants now.

Counted across the registry records on this site, refreshed daily.

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Who can participate

Ages eligible
40 Years to 95 Years
Sexes eligible
All
Accepts healthy volunteers
Yes
Sampling method
Non-probability sample

Study population

The patient of wearing complete maxillary dentures who visited the Department of Removable Prosthodontics at our institute were recruited for this study.

The volunteers were enrolled only after they provided written informed consent.

Inclusion criteria

  • wearing maxillary complete dentures

Exclusion criteria

Exclusion Criteria:

  • had been treated with a tissue conditioner, RDLs, and denture adhesives were excluded
  • showed obvious cognitive impairment
  • could not understand written or spoken Japanese
05

Study design

Enrollment
100 participants (actual)
Patient registry
No

Groups and cohorts

  • denture liners

    Evatouch Super (EVA; Neo Dental Chemical products, Washington, USA), GC RELINE (GCR; GC Dental Products Corp, Tokyo, Japan), Mucopren soft (MCP; Kettenbach GmbH \& Co KG, California, USA) Soften (SFT; KAMEMIZU CHEM, Osaka, Japan), FD Soft (FDS; KAMEMIZU CHEM, Osaka, Japan), and Bio Liner (BIO; Nissin Dental Products, Kyoto, Japan).

    Other: Evatouch Super

Interventions

  • OtherEvatouch Super

    The deterioration of RDLs may differ between in vitro conditions and the conditions encountered in denture wearers. We conducted an in vivo study to investigate how resilient denture liners (RDLs) changed in hardness when embedded in complete maxillary dentures worn by patients for one month in a clinical setting. We hypothesized that the hardness one month after application of the RDLs would be affected by the age, the condition of the saliva, the occlusal force, type of denture used, the patients habits related to smoking, drinking, wearing dentures while sleeping, and using a denture cleanser.

    Also known as: GC RELINE, Mucopren soft, Soften, FD Soft, Bio Liner

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What researchers measure

Primary outcomes

  1. hardness

    Denture liners's hardness was measured using a Vesmeter® (WaveCyber Corp, Saitama ,Japan) at the out of oral cavity.

    Time frame: 10 min

Secondary outcomes

  1. Salivary flow test(Unstimulated saliva)

    The participants were instructed to sit in an upright position with their heads inclined forward, which facilitated saliva collection at the floor of the mouth and overflow from the lip. The saliva was allowed to drip into a measuring cup for 5 min, and the flow rate was calculated in mL/min .

    Time frame: 5 min

  2. Salivary flow test(Stimulated saliva)

    The participants were instructed to chew a piece of paraffin gum until it became soft. The first collection of saliva was swallowed, the timer was set, and chewing was continued for another 2 min .The participants spat out the saliva at short intervals into a measuring cup. The participants were instructed not to eat anything (drinking water was allowed), smoke, or take snuff at least two hours before the tests.

    Time frame: 2min

Other outcomes

  1. pH measurement

    The pH values of the resting and stimulated saliva were obtained using a pH testing device (pH Spear, Eutech Instruments Pte Ltd, Ayer Rajah Crescent, Singapore). The investigator dipped the electrode approximately 2 to 3 cm into the saliva in a measuring cup and recorded the digitally obtained value.

    Time frame: 5 min

  2. Occlusal force measurement

    A GM10 occlusal force meter (Nagano Keiki, Tokyo, Japan) was used to measure the occlusal force. The maximum occlusal force applied by the functioning left and right first molars was measured three times, and the mean was used as a representative value.

    Time frame: 5 min

  3. Questionnaire

    Before starting the clinical trial, the participants were asked about the following environmental factors in a questionnaire: smoking, drinking, denture wearing during sleeping, and denture cleanser usage.

    Time frame: 10 min

07

Study locations

No study locations are listed for this record.

08

References and documents

Publications

  • Kimoto S, So K, Yamamoto S, Ohno Y, Shinomiya M, Ogura K, Kobayashi K. Randomized controlled clinical trial for verifying the effect of silicone-based resilient denture liner on the masticatory function of complete denture wearers. Int J Prosthodont. 2006 Nov-Dec;19(6):593-600. PubMed 17165299 ↗
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Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Dec 28, 2016, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT02587676
Lead sponsor
Nihon University
Responsible party
Yasuhiko Kawai (Professor Dr.Yasuhiko kawai, Nihon University) — Principal investigator
First posted
Oct 27, 2015
Start date
Jun 2013
Primary completion
Jul 2015
Completion
Dec 2016
Last update
Dec 28, 2016

Study contacts

Akina Ogawa
principal investigator · Depertment of removable prosthodontics Nihon University School of Dentistry at Matsudo

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

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