Objective: This study evaluated the release of fluoride from orthodontic band adhesives before and after exposure to fluoride varnish (FV), MI Paste (MIP), MI Paste Plus (MIPP), or no application, in neutral and acidic solutions. Background: White spot lesions (WSLs) occur in 73% of orthodontic patients. WSLs occur as a result of plaque accumulation, which leads to increased acidity of the oral cavity and subsequent enamel demineralization. Topical fluoride is frequently used as therapy for WSLs, in the form of toothpaste, mouth-rinse and varnish. In an effort to reduce demineralization around fixed appliances, fluoride-releasing adhesives have been employed, including glass ionomers, resin-modified glass ionomer cement (RMGIC), and compomers. Studies have shown a general fluoride release pattern of initial rapid release, followed by a steady decline, after which an external source of fluoride is required to recharge the adhesive. More recently, calcium-phosphate based pastes have been introduced as demineralizing agents, including MI Paste (MIP) and MI Paste Plus (MIPP). While the efficacy of these pastes has been supported, it is unknown how these pastes might impact the recharge of fluoride-releasing adhesives, as compared to topical fluoride. Methods: 140 discs (9 mm x 1.5mm) of Fuji Ortho Band LC Paste Pak (FOB) (n=70) or Reliance Ultra Band-Lok Blue (UBL) (n=70) were made, using custom-made Teflon molds. Fluoride release from the discs was evaluated at baseline (Part 1) and after exposure to a recharging protocol (Part 2). At baseline, discs were placed in either deionized water (DW) or lactic acid solution (LA) (pH=5) and fluoride release was measured at 24 hours, 1 week and 4 weeks post disc fabrication. For release post-recharge, discs were exposed to a: one-time exposure to FV at 4 weeks post disc fabrication; daily application of MIP; daily application of MIPP; or no application (NA). Fluoride release was measured at 24 hours, 1 week, and 4 weeks post-recharge. Results: In Part I, FOB displayed significantly greater fluoride release than UBL. In the FOB group, there was a significant effect of pH at all 3 time-points. FOB discs stored in LA displayed significantly greater fluoride release than those stored in DW. This effect was not seen in the UBL group. In Part II, the same pattern was observed. Within the FOB group in DW, the MIP and MIPP groups outperformed FV and NA groups, whereas in LA, the FV group was superior at 1 week. However, clinically significant amounts of fluoride were released in all FOB groups. The UBL group only released clinically significant amounts at 1 week, when exposed to FV or MIPP. Conclusions: FOB, a resin-modified glass ionomer cement, showed significantly higher fluoride release than UBL, a compomer, and release from FOB was significantly higher in a low pH environment comparable to a caries challenge. In FOB, all recharging protocols resulted in amounts of fluoride release conducive to remineralization.
| Date of Award | Jan 1 2016 |
|---|
| Original language | English |
|---|
| Supervisor | Shiva Khatami (Supervisor) |
|---|