Caries Prevention Effect of S-PRG Filler Incorporated in Denture Base Resins on Edentulous Elderly People
Condition: Dental Caries
MeSH terms: Dental Caries
Study type: Interventional

Summary: 
      The purpose of this study is to determine whether a novel material of S-PRG fillers
      containing in a daily-used resin denture base and their capability of fluoride release and
      recharge to elevate the salivary fluoride level and prevent dental caries in Thai middle-aged
      patients between 35-60 years of age who wear the resin denture.
    

Detailed description: 
      The study design is a 1.5-year, double blind randomized clinical trial, with 150 volunteers
      between 35-60 years of age wearing palatal removable partial denture containing with/without
      S-PRG fillers. This study will be performed in 3 local government hospitals located around
      Bangkok metropolitan, Ministry of Public Health, Thailand. The subjects will be assigned to
      the control group; resin denture base containing without S-PRG fillers and the experimental
      group; resin denture base containing 20% by weight of S-PRG fillers. Two parameters we can
      measure are; (1) Salivary fluoride level, accessed at different time point; on day 1, 14, 15
      and at 3, 12 months after wearing the denture, and (2) Caries incidence using ICDAS-II, taken
      at 18 months.

      Regarding an agreement with the participating dentists and dental assistants in the
      hospitals, patients in the waiting list of removable partial denture are screened according
      to our eligible criteria. If they meet eligibility criteria, a complete description is
      follow:

      "If you agree to participate in the study, at today's visit we will ask you some questions
      about your medical and dental health such as what medication that you are presently taking,
      and whether you use fluoride supplement except for toothpaste. You do not have to answer
      every question. The dentist will do a brief examination of your mouth looking to see if you
      have any decay. You will not be able to participate in this study if you have obvious
      untreated tooth decay.

      Following completion of the questionnaire and examination, we will do a simple test on your
      saliva. We will collect stimulated saliva by having you to chew a piece of wax for 5 minutes.
      You will spit all the saliva formed during those 5 minutes into a cup. We will measure the
      volume of the saliva produced. You will have to have a normal flow rate to participate.

      Collecting this information, doing the saliva test, and completing the dental examination
      will take about 30 minutes of today's appointment. You may refuse to participate in any of
      the saliva test or answer any question or item in the questionnaire. If that is the case, you
      will not qualify for the study. If you do qualify and agree to take part, the dentist will
      take a mold of your mouth to make an upper resin denture to replace your missing teeth for
      you to wear. This is a routine dental procedure. Some subjects may gag while the mold is
      being taken for the denture. The dentist has methods to help you control the gagging reflex.

      Depending on which group you are assigned, your resin denture will be made from standard
      material or the standard material containing some new type of biological material. This new
      material we are testing is being used in the formulation of dental product as filling
      materials.

      At the next appointment, approximately two week later, you will come in to have the denture
      fitted for you. Slight discomfort may occur at the gum margin where the denture can pinch.
      The plate will be adjusted to relieve any pinching. On rare occasions, allergy to the resin
      denture base may occur. We will stop your participation in the study if you have an allergy
      to the resin denture.

      We will give you the resin denture and need you to wear it all day excluding when you sleep
      at night. You must take it out to brush your teeth. You may clean the denture with water and
      the same toothbrush that you use to brush your teeth before keeping the denture in the
      denture storage box. We do not want you to use anything else on the denture except material
      we supply. You will receive a box for keeping your denture, toothbrush and toothpaste to
      brush your teeth at home.

      At the first 14 days once you receive the denture, we do want you to soak your denture in a
      denture storage box containing tap water every night when you sleep. After that we will
      supply you a tube of fluoride gel for storing the denture instead of tap water. We will ask
      you to apply the gel (approximately 1 cm of length) to the denture and spread out totally on
      both side of the denture before keeping in the denture box during sleeping every night for
      1.5 years.

      After wearing the denture, you will be asked to return to the clinic for check-up and recall.
      We will collect your saliva while wearing the denture periodically for a total of six times
      within one year according to our schedule for the analysis of the fluoride level.

      At 1.5 years, you will be asked to return to the clinic and the dentist will do a dental
      examination for follow-up. That will conclude your participation in the study.

      We will assess the salivary fluoride at different time point during 1 year. The fluoride
      level of saliva will show us the capability of the new material on the fluoride release and
      recharge. The follow up period will be extended for 6 more months. The caries information
      collected at 1.5 years will show us the incidence of new caries. All procedures will be done
      at the dental clinic of the hospital. The subjects will be identified by a number assigned
      only. The principle investigator and the project coordinator will have to access to the code
      which will remain locked at all time. The saliva collected from the subjects will be
      discarded immediately after complete analysis.

      The sample size assessment is considered based on the long term outcome, caries incidence,
      and the short term outcome, salivary fluoride concentration, of the study. The optimal sample
      size to address both outcomes in the study and allow for a 20% drop out rate would be 75
      subjects per group (150 total) to provide sufficient statistical power to detect the
      difference in mean caries incidence between the control and the intervention group.

      Collected data will be entered into a computer database and analyzed with STATA software
      version 12 for Windows. The statistical significance level will be set at α = 0.05.

      The analysis plan for salivary fluoride level at each phase of follow up is based on
      two-sample t test and linear regression adjusting for confounders (age, number of remaining
      teeth).

      Data analysis for caries incidence will be recorded per surface using ICDAS-II severity
      scores at 1.5 years. The caries outcome is defined as score 1 to 6 and 1 to 2 for root
      caries. Two-sample t test or linear regression with adjusting for age will be performed to
      assess the different between the control and the intervention group in the mean number of new
      surface caries (dmfs) ± standard deviations at 1.5 years follow-up examination.
    

Intervention name(s): S-PRG filler; PMMA resin
Intervention type(s): Device; Device
Intervention description(s): Surface pre-reacted glass-ionomer (S-PRG) filler is a new type of biological material. This new material is being used in the formulation of dental product as filling materials. It has an anti-plaque effect which will release ions to alter the pH of the surrounding environment when it comes into contact with water or acidic solutions. These ions will exert their effect on caries prevention.
The amount of S-PRG filler that is put in the standard resin denture base is 20% by weight. They are incorporated into the resin denture base and maintain the mechanical properties as required by ISO 1567.; Polymethyl methacrylate (PMMA) resins have been used for the fabrication of resin denture base for 50 years. The advantages of PMMA resin that most notably is the ease of fabrication with very simple equipment but a limitation is the fragility because of its physical properties that include low flexural strength and surface hardness.
Other intervention name(s): Surface pre-reacted glass-ionomer filler; Polymethymethacrylate resin; resin denture base
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: resin denture base