Question: What in cheese allows it to protect tooth enamel?
About the article "Cheese", section "Dental health".

Candidate passages:
Some studies claim that cheddar, mozzarella, Swiss and American cheeses can help to prevent tooth decay.
Several mechanisms for this protection have been proposed:
 The calcium, protein, and phosphorus in cheese may act to protect tooth enamel.
 Cheese increases saliva flow, washing away acids and sugars.
The bell stage is known for the histodifferentiation and morphodifferentiation that takes place.
The dental organ is bell-shaped during this stage, and the majority of its cells are called stellate reticulum because of their star-shaped appearance.
The bell stage is divided into the "early bell stage" and the "late bell stage".
Cells on the periphery of the enamel organ separate into four important layers.
Cuboidal cells on the periphery of the dental organ are known as outer enamel epithelium (OEE).
The columnar cells of the enamel organ adjacent to the enamel papilla are known as inner enamel epithelium (IEE).
The cells between the IEE and the stellate reticulum form a layer known as the stratum intermedium.
The rim of the enamel organ where the outer and inner enamel epithelium join is called the "cervical loop".
In summary, the layers in order of innermost to outermost consist of dentin, enamel (formed by IEE, or 'ameloblasts', as they move outwards/upwards), inner enamel epithelium and stratum intermedium (stratified cells that support the synthetic activity of the inner enamel epithelium) What follows is part of the initial 'enamel organ', the center of which is made up of stellate reticulum cells that serve to protect the enamel organ.
This is all encased by the OEE layer.
Other events occur during the bell stage.
The dental lamina disintegrates, leaving the developing teeth completely separated from the epithelium of the oral cavity; the two will not join again until the final eruption of the tooth into the mouth.
The crown of the tooth, which is influenced by the shape of the inner enamel epithelium, also takes shape during this stage.
Throughout the mouth, all teeth undergo this same process; it is still uncertain why teeth form various crown shapes—for instance, incisors versus canines.
There are two dominant hypotheses.
The "field model" proposes there are components for each type of tooth shape found in the ectomesenchyme during tooth development.
The components for particular types of teeth, such as incisors, are localized in one area and dissipate rapidly in different parts of the mouth.
Thus, for example, the "incisor field" has factors that develop teeth into incisor shape, and this field is concentrated in the central incisor area, but decreases rapidly in the canine area.
The other dominant hypothesis, the "clone model", proposes that the epithelium programs a group of ectomesenchymal cells to generate teeth of particular shapes.
This group of cells, called a clone, coaxes the dental lamina into tooth development, causing a tooth bud to form.
Growth of the dental lamina continues in an area called the "progress zone".
Once the progress zone travels a certain distance from the first tooth bud, a second tooth bud will start to develop.
These two models are not necessarily mutually exclusive, nor does widely accepted dental science consider them to be so: it is postulated that both models influence tooth development at different times.
Other structures that may appear in a developing tooth in this stage are enamel knots, enamel cords, and enamel niche. 
The microstructure of the enamel of VPL/JU/NKIM/25 has been studied.
Unlike other gondwanatheres, it has enamel consisting of three layers—radial enamel, tangential enamel, and PLEX.
The rows of small, round enamel prisms are separated by interprismatic matrix that forms crystalls oriented at right angles relative to the prisms.
Prisms arise at the enamel-dentine junction, run through the enamel, and meet the outer enamel at a high angle.
These features of the enamel are apparently adaptations that protect the tooth from cracks. 
Hard tissue formation.
Enamel formation is called amelogenesis and occurs in the crown stage (advanced bell stage) of tooth development.
"Reciprocal induction" governs the relationship between the formation of dentin and enamel; dentin formation must always occur before enamel formation.
Generally, enamel formation occurs in two stages: the secretory and maturation stages.
Proteins and an organic matrix form a partially mineralized enamel in the secretory stage; the maturation stage completes enamel mineralization.
In the secretory stage, ameloblasts release enamel proteins that contribute to the enamel matrix, which is then partially mineralized by the enzyme alkaline phosphatase.
The appearance of this mineralized tissue, which occurs usually around the third or fourth month of pregnancy, marks the first appearance of enamel in the body.
Ameloblasts deposit enamel at the location of what become cusps of teeth alongside dentin.
Enamel formation then continues outward, away from the center of the tooth.
In the maturation stage, the ameloblasts transport some of the substances used in enamel formation out of the enamel.
Thus, the function of ameloblasts changes from enamel production, as occurs in the secretory stage, to transportation of substances.
Most of the materials transported by ameloblasts in this stage are proteins used to complete mineralization.
The important proteins involved are amelogenins, ameloblastins, enamelins, and tuftelins.
By the end of this stage, the enamel has completed its mineralization.
A residue may form on newly erupted teeth of both dentitions that may leave the teeth extrinsically stained.
This green-gray residue, Nasmyth membrane, consists of the fused tissue of the reduced enamel epithelium and oral epithelium, as well as the dental cuticle placed by the ameloblasts on the newly formed outer enamel surface.
Nasmyth membrane then easily picks up stain from food debris and is hard to remove except by selective polishing.
The child’s supervising adults may need reassurance that it is only an extrinsic stain on a child’s newly erupted teeth. 
The enamel organ, also known as dental organ, is a cellular aggregation seen in histologic sections of a developing tooth.
It lies above a condensation of ectomesenchymal cells called the dental papilla.
Historically, enamel organ has been the term to describe this structure, but it was attempted unsuccessfully in recent years to change the name to dental organ in order to better represent its multiple functions apart from enamel formation.
The enamel organ functions in the formation of enamel, initiation of dentin formation, establishment of the shape of a tooth's crown, and establishment of the dentogingival junction.
The parts of the enamel organ include the inner enamel epithelium, outer enamel epithelium, stratum intermedium, and the stellate reticulum.