What is on rats’ teeth? - briefly
Rats’ incisors have a hard enamel coating on the cutting edge and a softer dentin layer behind it, enabling perpetual growth. A thin layer of bacterial plaque also adheres to the tooth surface.
What is on rats’ teeth? - in detail
Rats possess continuously growing incisors that differ markedly from the molars of many mammals. The exposed portion of each incisor consists of three primary layers:
- Enamel – a highly mineralized outer coat composed mainly of hydroxyapatite crystals arranged in a tightly packed, prismatic structure. Enamel provides exceptional hardness and resistance to abrasion.
- Dentin – underlying the enamel, this tissue contains a lower mineral content and a network of microscopic tubules. Dentin contributes to the overall strength of the tooth while allowing limited flexibility.
- Pulp cavity – the innermost region houses nerves, blood vessels, and connective tissue, supplying nutrients and sensory feedback.
The relentless growth of rodent incisors pushes worn material forward, exposing fresh enamel. Saliva, rich in calcium and phosphate ions, continuously bathes the tooth surface, facilitating remineralization and protecting against demineralization. A thin biofilm of oral bacteria adheres to the enamel, forming a natural plaque layer. This microbial film includes species such as Streptococcus and Lactobacillus, which metabolize dietary carbohydrates and produce acids that can erode enamel if not balanced by salivary buffering.
Additional surface features include:
- Wear facets – flat, polished areas created by gnawing on hard objects; these facets reveal the enamel‑dentin junction and are essential for efficient food processing.
- Peri‑incisal gingiva – a ring of gum tissue that surrounds the base of the incisor, providing a seal that prevents debris accumulation and infection.
- Micro‑cracks – microscopic fissures that develop from repetitive stress; they are typically self‑healing due to the high turnover rate of enamel in rodents.
Overall, the composition of rat incisors reflects a dynamic equilibrium between mineralized tissue, saliva‑mediated maintenance, and microbial colonization, enabling the animal to sustain its characteristic gnawing behavior throughout life.