An interventional study of Nobio composite and traditional composite in Dental Caries and Denture, Partial, Removable, sponsored by University of California, San Francisco. Completed at 1 site in United States. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-03-12.
Sponsored by University of California, San Francisco · Not applicable, Interventional, and Prevention
Nobio has developed dental restorative materials with long term antibacterial properties in order to fight recurrent decay/caries around restorations. These composites with incorporated non-leaching antibacterial agents might overcome the vicious circle of newly developed cavities around freshly placed fillings.
The investigators will ask lower partial denture wearers to allow them to place a "gap model" with the Nobio-composite and enamel slab in one denture flange. In the other denture flange a gap model with a standard composite will be placed as control. In the laboratory the investigators will test with established methods for demineralization/caries prevention in the test and control enamel slabs, respectively.
As a major issue in dentistry, it has been stated that two-thirds of all restorative dentistry involves the replacement of failed restorations. Secondary caries indicates a lesion developing at the margins of an existing restoration and is the major reason for replacement of amalgam and composite resin restorations in operative dentistry.
In research the use of experimental intra-oral caries models dealing with caries prevention has increased. The most realistic experimental model is the in vivo model that uses living teeth, followed by the in situ model using specimens with natural surfaces held in the mouth during the experimental period. In situ models have the potential to study both fundamental aspects of the caries process as well as more applied research problems in caries prevention in human subjects without actually causing caries in the natural dentition.
To simulate a failed interface between a tooth and a restoration, a gap can be formed between an enamel slab and the restoration prior to a cariogenic challenge. The "gap-model" will be inserted for instance into the denture flanges, and the cariogenic challenge occurs inside the mouth during the wear period..
Nobio has developed dental restorative materials with long term antibacterial properties in order to fight recurrent decay around restorations. These composites with incorporated non-leaching antibacterial agents might overcome the vicious circle of newly developed cavities around freshly placed fillings. The ongoing caries activity due to bacteria around the filling may be interrupted by quaternary ammonium silica dioxide (QASi) particles incorporated in the test composite at 1.2% (by weight). These particles are members of the Nobio Antimicrobial Particle (NAP) family (Nobio, Israel). QASi are synthesized to form a high concentration of antimicrobial groups that are covalently-bound onto a carrier core, such as silica. The resulting micro or nano-sized QASi particles are mixed with other fillers of the dental composite material, during manufacturing. Following in situ placement and light-initiated polymerization, QASi particles are permanently retained in the final dental restoration. Laboratory studies have shown that the quaternary ammonium silica particles are potent antibacterial agents, do not leach out in contrast to other antimicrobials or caries preventive active substances, inhibit the breakdown of the composite, and maintain antibacterial activity over time.
The study is an in situ study. Subjects, wearing lower partial dentures with acrylic flanges on both sides of the mouth will be recruited. On each side of the denture an enamel slab will be placed next to a composite, separated by a tiny gap. On one side of the denture the composite will be Nobio's antibacterial composite, on the other side a regular composite (a Nobio composite w/o particles or another commercial composite will serve as control material. Enamel slab and composite will be recessed into the flange, allowing microbial plaque to accumulate on top of it and especially in the gap.
After wearing the dentures for four weeks with the slabs, decalcification - ΔZ mineral loss - in the enamel slabs adjacent to the gap will be determined by cross-section microhardness testing in the laboratory. Average ΔZ mineral loss will be calculated for the Nobio group and the control group, and difference will be tested for statistical significance.
1,107 studies on the registry are indexed under Dental Caries; 197 are open to participants now.
This study's enrollment of 25 is below the median of 60 across 915 interventional studies indexed under Dental Caries.
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Exclusion Criteria:
On the Nobio flange side of the lower partial denture the gap model will include a double sterilized piece of human enamel, a small gap, and next to it the Nobio composite.
Device: Nobio composite
On the traditional composite flange side of the lower partial denture the gap model will include a double sterilized piece of human enamel, a small gap, and next to it a traditional composite.
Device: traditional composite
Nobio has developed a bactericidal composite, which does not leak out the bactericidal nano fillers
traditional composite which has no bactericidal activities
Mineral Loss ΔZ
The mineral loss is determined in the laboratory using cross-sectional microhardness testings of the enamel after the 4-weeks wearing period of the gap-model. The overall relative mineral loss, ΔZ, for each sample is calculated by creating a hardness profile curve by plotting normalized volume percent mineral against distance from the outer enamel surface. The area under the curve that represents ΔZ (µm \* vol % mineral) is calculated using Simpson's integration rule.
Time frame: mineral loss ΔZ is determined after the 4 week wearing period
each participant enrolled had TWO flanges (right and left side of the mouth) in her/his removable partial denture; the study design is a split-mouth design - in one side the "Nobio Flange"- the Nobio composite was inserted, one the control side - the "control flange" - the traditional control composite was inserted
| Milestone | Nobio Flange | Traditional Composite Control Flange |
|---|---|---|
| Started | 25 | 25 |
| Completed | 25 | 25 |
| Not completed | 0 | 0 |
The mineral loss is determined in the laboratory using cross-sectional microhardness testings of the enamel after the 4-weeks wearing period of the gap-model. The overall relative mineral loss, ΔZ, for each sample is calculated by creating a hardness profile curve by plotting normalized volume percent mineral against distance from the outer enamel surface. The area under the curve that represents ΔZ (µm \* vol % mineral) is calculated using Simpson's integration rule.
| vol% * μm] | Nobio Flange | Traditional Composite Flange |
|---|---|---|
| Mineral Loss ΔZ | 235 ± 354 | 774 ± 556 |
Collected over Four weeks study period, while wearing the composite inside the denture flanges. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Nobio Flange | 0/25 (0%) | 0/25 (0%) | 0/25 (0%) |
| Traditional Composite Flange | 0/25 (0%) | 0/25 (0%) | 0/25 (0%) |
25 participants contributed 25 lower partial dentures. Each partial denture had two flanges - one side for the Nobio unit, the other side as the control composite unit
| Age, Continuous(years) | All Study Participants |
|---|---|
| Mean | 63.7 ± 14.1 |
| Sex: Female, Male(Participants) | All Study Participants |
|---|---|
| Female | 8 |
| Male | 17 |
| Ethnicity (NIH/OMB)(Participants) | All Study Participants |
|---|---|
| Hispanic or Latino | 3 |
| Not Hispanic or Latino | 22 |
| Unknown or Not Reported | 0 |
| Region of Enrollment(participants) | All Study Participants |
|---|---|
| United States | 25 |
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University of California, San Francisco