Anti-caries and Remineralizing Agents

What are the two main categories of fluoride's cariostatic action?

Anticariogenic effect (crystal solubility, demineralization, remineralization) and Antimicrobial effect

How are calcium ions arranged in the hydroxyapatite crystal?

Two ways: columnar (along the column of the HA crystal) and triangular (surrounds the OH- ion)

Why does the outer surface of the HA crystal attract acid attack?

PO4 on the outside gives the crystal a negative charge, making the tooth structure surface negative

What happens to a-axis dimension when fluorapatite (FA) forms by OH- replacement with F-?

It decreases, because F- is smaller than OH-, making the crystal more compact

Besides displacing OH-, how else can fluoride incorporate into the crystal?

By forming a hydrogen bond (OH-F) with neighboring OH- ions

During tooth formation, fluoride may substitute for which ion group?

Carbonate groups

What are the net effects of fluoride's improved crystallinity (increased stability, fewer imperfections, larger crystals)?

Low acid solubility, decreased demineralization rate, less susceptibility to caries

In the presence of fluoride, what does H+ react with instead of PO4 during acid attack?

Fluoride, forming HF acid - this saves the HA crystal and removes H+ from the environment

What critical pH shift does fluoride cause in enamel dissolution?

Shifts from 5.5 to about 5.0

What forms on partially dissolved crystals during remineralization in the presence of fluoride?

A fluorapatite-like (CaF2-nature) shell/coating

At neutral pH 7, what F concentration is needed to be bactericidal?

About 12,000 ppm (vs only 6-8 ppm needed at pH 5)

Which enzyme is inhibited by fluoride (via HF) at low pH, disrupting bacterial glucose metabolism?

Enolase (optimal pH 7.3-7.7); converts 2-P-glycerate to PEP

Why does ATPase inhibition by fluoride harm bacteria at low pH?

ATPase is the proton pump; without ATP it can't remove acid, further acidifying and killing the cell

What two-stage process forms CaF2 material at high fluoride concentration (>100 ppm)?

Release of Ca from enamel, then reaction with fluoride

How long can CaF2 globules last on the tooth surface?

Up to 3 months - why fluoride varnish is reapplied every 3 months

When is systemic fluoride most critical for developing teeth?

Birth to 8 years, with critical ages 12-30 months

What fluoride compound is a toothpaste-only ingredient needing salivary enzyme hydrolysis to release F-?

Sodium Monofluorophosphate (MFP) - delivers 1000-1200 ppm F, OTC only

Why is NaF less effective for dentin hypersensitivity than SnF2?

The F- ion is small with limited ability to occlude dentinal tubules

What makes Stannous Fluoride (SnF2) unique?

2 active ions (attraction to calcium AND phosphate), water insoluble after uptake, may cause discoloration

How does Sn2+ prevent lamination of the lesion surface?

Acts as a crystal growth inhibitor, adsorbing to active sites, limiting both remineralization and further dissolution

What are the 4 main components of 38% Silver Diamine Fluoride (Advantage Arrest)?

62% water, 25% silver, 8% ammonium, 5% fluoride

What is the pH and color of SDF (Advantage Arrest)?

pH 10, blue tinted liquid; 3-year shelf life, light sensitive

Does SDF stain sound enamel or dentin?

No - only decayed tissue; it does temporarily discolor soft tissue and permanently stain clothing/countertops

What does SMART stand for as a post-SDF treatment option?

Silver Modified Atraumatic Restorative Treatment

What ppm F does 5% NaF varnish deliver, and what caries reduction?

22,600 ppm F; up to ~40% caries reduction; lasts up to 3 months, applied 2-4x/year (WHO)

Who should NOT receive fluoride varnish?

Low caries risk patients

What is the pH range of Acidulated Phosphate Fluoride (APF) and its main caution?

pH 3.0-4.0; degrades glass-ionomer, porcelain crowns/veneers; avoid with exposed roots (hypersensitivity)

Why does APF's low pH increase fluoride uptake into enamel?

Low pH etches enamel, increasing porosity and preventing surface-blocking, prolonging mineral ion access

What do CPP and ACP do in Recaldent (CPP-ACP) technology?

CPP binds Ca/P keeping them soluble and binds tooth/plaque surfaces; ACP is free Ca/P available for incorporation into tooth structure

How does functionalized Tri-Calcium Phosphate (fTCP) coexist with fluoride in toothpaste?

An organic coating shields calcium from fluoride until saliva breaks down the coating during brushing, releasing Ca/P at the tooth surface

What is notable about polyphosphate systems (e.g. STMP) and ion diffusion?

Their protective layer does not hinder diffusion of Ca2+ and F- ions into enamel

Why are bioactive/biomimetic systems (self-assembling peptides, HAP) advantageous over fluoride alone?

High fluoride concentration causes surface lamination limiting full remineralization; these agents achieve deeper remineralization and dosage can be increased without toxicity risk

How do self-assembling peptides (e.g. P11-4, Curodont Repair) regenerate enamel/dentin?

Monomers diffuse into the subsurface lesion, assemble into a 3D matrix, attract calcium phosphate from saliva, and template de novo hydroxyapatite crystal formation

What are the multifunctional benefits of Hydroxyapatite (HAP) as a bioactive agent?

Induces remineralization, inhibits demineralization, relieves hypersensitivity, controls biofilm/reduces gingivitis, buffers acid; biocompatible with no dosage limit