Dentes: ( = teeth, dentition, upper and lower dental arches or arcades, complete dental arcade) Teeth are tools, weapons, sensory organs, and a means for nutritional competence. They are objects of beauty, long utilized for jewelry and to enhance human appearance. They have been carved into beautiful objects of art, made into sporting equipment, and turned into delicate tools. Humans have desired mammalian teeth throughout their evolution; wherever human archaeological sites are found, so are the remains of tools and jewelry made from the teeth of animals. Ferrets, or rather their polecat progenitors, use their dentition to explore their environment, defend themselves against predation, warn away interlopers, perform sexual rituals as a prelude to reproduction, play with siblings, carry and care for young, excavate burrows, manipulate, move or carry objects, groom themselves, and, yes, to kill prey and consume them. Because of the obvious importance of the teeth in nutrition and behavior, it is fitting the ferret's dentition be discussed in detail. Deciduous and Permanent Dentitions: Ferrets, like humans and most mammals, have two sets of teeth during their lifespan -- those being the deciduous and permanent dentitions. While both sets have incisors, canines and premolars, molars are only found in the permanent arcades. The deciduous dentition is designed to get the ferret through early growth, when the skull and jaws are rapidly changing shape and size. Because the skull is small and still developing when the dentition erupts, adult teeth would be too large to fit within the dental arcades. This problem is exacerbated by the need to wean the kit as soon as possible; kits have almost explosive growth curves, which require a tremendous amount of food to fuel. Jills can provide only so much milk, and as the kits grow, something more substantial is needed. One solution is for the jill to provide portable, condensed packages of nutrition to the growing kits; otherwise known as prey carcasses. This means teeth are needed prior to cessation of skull growth. These problems are met by using a "throw-away" set of teeth; not as large, as hard, nor as durable as the permanent dentition, which makes them cheaper from a nutritional standpoint, but nonetheless capable of standing up to short-term use. These "throw-away" teeth are the deciduous dentition, and they will be discarded as soon as the skull is large enough to house the permanent dental arcades. (Synonyms deciduous dentition = baby teeth, deciduous arches or arcades, deciduous dental arches or arcades, deciduous teeth, dentes decidui, milk teeth, primary dentition, temporary teeth. Synonyms permanent dentition = accessional teeth, adult teeth, dentes permanentes, permanent arches or arcades, permanent dental arches or arcades, permanent teeth, secondary dentition). The deciduous dentition needs to be in position within the first month of the ferret's life, prior to when the jill begins to wean the kit. Tooth formation and growth (= odontogenesis) takes time, so the ferret is born with some of the teeth already in place (= natal teeth). Others have crowns already formed so they can erupt within the first month of life (= neonatal teeth). In ferrets, the deciduous dentition mimics the permanent teeth in that they have a similar appearance and function. Most of the ferret's deciduous teeth emerge at about 20 days, which is near the time the jill first starts to supplement the diet with hard foods. These erupted teeth are mostly in place about a week later, and by day 40, while the jill may still allow the kits to suckle; they are more or less able to survive exclusively on solid foods. Just after this time, the permanent teeth begin to erupt, replacing the soft, temporary teeth with a rugged dentition designed to last them the rest of their lives. Basic Tooth Anatomy: Each tooth is grown from an individual bud (= tooth germ) inside the maxilla and mandible within blood-rich chambers that eventually fill with bone to form the dental alveolus (= tooth socket). They grow from the occlusal surface (= contact surface, biting surface) downwards, forming the enameled crown first. When the crown is more or less complete, the roots begin to form, and the tooth ultimately erupts through the gums (= gingival emergence). Inside the tooth is the pulp chamber, which contains the nerve and blood vessels that nourish the dental tissues. These nerves and vessels extend through the root canal to the apex (= root tip), and exit the tooth to attach to sources within the mandible and maxilla (some teeth have more than one root, thus more than one apices). The tooth is secured to the dental alveolus by the periodontal ligament. This connective tissue is wrapped around the root, connecting the cement-covered dentine to the alveolar bone and forming a strong -- yet flexible -- joint. The periodontal ligament allows subtle movement of the tooth during chewing and biting, which is perfect for holding the teeth in position, but helping to shield them from severe biomechanical stresses that could cause fractures under heavy load. Teeth can be divided into two basic parts; the crown and the root. The crown (= corona) is the erupted portion of the tooth and is swathed in enamel (the hardest substance in the body -- it will produce sparks when struck by steel). The root (= radix) is covered with a hard, bone-like substance called cement (= cementum), and is attached to the crown at the neck (= cervical region, dental cervix). Under the thin layer of enamel and cementum is the dentine (= ivory), which is the substance that makes up most of the tooth. Dentine is very hard and for centuries was the material of choice for objects demanding durability, such as piano keys or billiard balls (elephant tusks are dentine; the small enamel crown present at eruption wears away rapidly with heavy use). Bone, enamel, cement and dentine are all variants of the same biomaterial, calcium hydroxyapatite, Ca10(PO4)6(OH)2. These substances are composed of a protein framework (= matrix) filled with ultra-fine crystals of the inorganic salt. The difference between them is in how the crystals are formed and interconnected (including the matrix and the amount of water molecules). Tooth enamel, although nearly chemically identical to bone, is far harder (which makes it far more durable). However, hardness exacts a price in brittleness. While enamel is hard, it will easily fracture under sudden impact, such as when a ferret falls and the tip of their tooth strikes a concrete floor. In these circumstances, enamel (or any crystalline hydroxyapatite material, including bone) acts like a ceramic, and fractures with the same patterns seen in broken glass. In ferret canines, this usually means the tip will fragment, and a partial U-shaped flake of material will pop off the surface of the tooth (usually in the front or just to one side; the size and position depending on impact force and angle). The tip actually shatters, and the flake is a portion of a larger cone; imagine a long, thin slice out of the side of a funnel. Ferrets also break off the tips of their canines by pulling at cage doors, or in play, but the fracture patterns are usually different. This specialized tooth fracture mimics the sudden force applied when a B-B hits glass, and is usually diagnostic of a fall (shattered tip, cone-shaped flake). The bumps, points and ridges on the top of the crowns are called cusps (cones, tubercula dentis, tubercles). The cusps on specific teeth are diagnostic of species; that is, you can identify a mammal from the cusp pattern alone, a trick discovered by Cuvier more than 150 years ago. Thus, while a root fragment has little or no zooarchaeological value, a crown is quite valuable. They can be traced to specific animals, yielding clues to past ecology, hunting patterns, and environmental conditions, among others. The cusps are modeled in dentine and covered with a thick layer of enamel, creating a very hard projection on the tooth. This allows the ferret the ability to slice through tough connective and muscle tissue, and crush bones to get to the valuable and nutritious marrow. In the ferret, most of the cusps are heavily modified into cutting blades, and are unsuitable for food grinding. Like cats, ferrets do not masticate their food; rather, they cut it into chunks that can be wolfed down rapidly. On the top of the jaw, along the line of tooth sockets, is the alveolar ridge (= alveolar margin, alveolar process). Covering this bone is the gingivia (= gums, oral gingivia, oral epithelium), which is filled with tiny blood vessels just under the surface. These vessels feed the rapidly growing epithelium (= outer skin) covering the gingivia, which explains why gums look pink. The gingivia has to grow briskly to replace skin cells mechanically lost during predation and food consumption, to rapidly repair injuries, such as biting the tongue or ripping the inside of the cheek, and to help fight infections. This exceptionally vascular region will bleed from every tiny nick and scrape, which is often the cause of unnecessary apprehension for new ferret owners -- it takes very little blood to impart the appearance of serious injury. Bleeding is normally self-limiting and of little consequence, and benefits the ferret by washing pathogens from the wound. Serious cuts, or those which cause substantial or prolonged bleeding, should treated by a veterinarian as soon as possible. Whitish, yellowish, bluish or grayish gums are good indications that the ferret is ill, and should be evaluated by a veterinarian. Large bumps along the gums or on the roof of the mouth may be caused by infections or abscesses, or could be a sign of an oral tumor, and should be treated by a veterinarian. The health of the gingivia is necessary for the health of the underlying bone. The gingivia covers the alveolar ridge holding the teeth, and forms a tiny pocket around the base of the tooth, called the gingival sulcus. In a healthy mouth, the gingival sulcus is held close to the tooth enamel by the gingival cuff, but with inflamed or infected mouths, the sulcus is reddened and swollen. This opens the gingival sulcus, creating a "pocket" that can fill with bacteria and debris, exacerbating the original problem. In short-term cases, such as when a piece of food scratches the ferret's gums or the gum is injured during play, the inflammation is usually self-limiting. Most gingivitis is a result of injury or local inflammation, and is self-limited, yet common. Indeed, some odontogists claim every mouth has gingivitis to one degree or another, which flares and resolves with little notice. In other words, at any one time you can find some degree of gingivitis within a ferret's mouth, making them litle different than any other mammal. However unpleasant, in long-term cases of gingivitis, the real danger is that periodontitis can set in. Bob C [Moderator's note: Part 2 of this article has already been received and will appear in a future FML. If you must have it NOW, please e-mail me at the ferret-request address and I'll send you a copy. (It's shorter than this part.) BIG] [Posted in FML issue 3504]