#TeethandDigestion

#Biology

#HumanDigestiveSystem

Introduction

• Mechanical digestion is the breakdown of food into smaller pieces without chemical change to the food molecules

  
  

• It is mainly carried out by the chewing action of the teeth, the churning action of the stomach and the emulsification of fats by bile in the duodenum

• Teeth are held firmly in the bone of the jaw

  • They are used for chewing to increase the surface area of the food so that it can be exposed to saliva and other digestive juices and broken down more quickly

    
    

• Teeth are classified as diphyodont, indicating there are two successive sets during a person's life: primary (deciduous) and permanent teeth

Teeth Types

• The differing shapes and sizes of teeth enable them to perform slightly different functions:

  • Incisors - chisel-shaped for biting and cutting

  • Canines - pointed for tearing, holding and biting

  • Premolars and molars - larger, flat surfaces with ridges at the edges for chewing and grinding up food

    
    

• Most adults possess 32 permanent teeth, comprising 8 incisors, 4 canines, 8 premolars, and 12 molars, while children typically have 20 primary teeth

Teeth Structure

• Jaw Bone :- The jaw consists of two main bones—the upper jaw (maxilla) and the lower jaw (mandible). The mandible is the largest and most mobile component of the jaw structure.

• Gum :- The tissue of the upper and lower jaws that surrounds the base of the teeth. Also called gingiva

• Enamel :- Tooth enamel is the hard, visible, outermost layer of your teeth that protects them from damage. Composition of Enamel is 95% calcium and phosphorus, 4% water, and 1% proteins.

  
  

• Dentine :- Dentin is the hard tissue that makes up the bulk of a tooth, located between the enamel and cementum.

  Dentin is made up of 70% inorganic material, 20% organic material, and 10% water. It's harder than bone but softer than enamel. Dentin is made up of a dense matrix of small, wavy, branching tubes called dental tubules. These tubules carry nutrients and fluids from the pulp chamber to the dentin layer

• Cement :- Dental cement is specifically made to resist bite pressure produced by the teeth and jawbones. This cement is an adhesive material that's highly resistant to decay and can easily blend with the restoration and natural tooth for making repairs

• Pulp Cavity :- The pulp cavity is a hollowed-out space in the center of a tooth that contains nerves and blood vessels that keep the tooth alive

  
  

• Nerve :- A tooth nerve is located in the pulp, which is the soft tissue in the center of a tooth. The nerve's main function is to sense hot and cold

• Blood Capillaries :- The density of the capillary bed is greatest toward the periphery of the pulp, where the cell population is also greatest. The diameters of the arteries have been observed to vary with respect both to different teeth and to location within the same tooth.

Is Teeth a Bone

• No, teeth are not bones. While they may look similar and are both hard substances in the body, they have some key differences: 

  
  

  • Regeneration: Bones can heal themselves when broken, but teeth cannot. 

  • Marrow: Teeth do not contain marrow, unlike bones. 

  • Composition: Teeth and bones are made from similar materials, but they have distinct attributes that set them apart. 

• The misconception that teeth are bones may arise from the fact that both contain calcium. More than 99 percent of your body's calcium can be found in your bones and teeth.