- The structure of the tooth: the main decoration
- Permanent teeth
The appearance and the "inner meaning" tooth
A tooth is comprised of crown and root neck. Crowns are located above the gum, and come in two forms: chewing surface (side teeth) without chewing surfaces (front teeth).
The root of the tooth located in the jaw bone cell and attached to it a special bundle - periodontitis. Between the crown and the root is the neck of the tooth - a slight narrowing of the space, with tight adjacent gum.
The crown of the tooth is composed of two layers of hard tissue - the enamel (which is on the surface) and dentin. Inside the hollow crown, it is a tooth with a cavity located inside the soft tissue (pulp). The cavity of the tooth passes into the tooth root canal (root canal), which also contain pulp and open at the top of the tooth root opening. On top of the tooth root is also covered by the hard tissue, called cement.
Total human tooth 32 (16 on upper and lower jaw). Various functionally teeth differ form crowns and the number of roots. In addition to the actual tooth to tooth body includes hole and the surrounding jaw bone, covered with mucous membrane of the gums, ligament that holds the tooth in the hole, blood vessels and nerves.
How does tooth
Each tooth has four surfaces:
- vestibular - she turned to her lips and cheeks;
- lingual - turned to the language;
- contact - facing the adjacent teeth;
- chewing - it is the surface directed to the teeth of the opposite number; or the cutting edge of incisors and canines; This is also called the occlusal surface (ie the surface of the clamping).
The teeth of the upper and lower jaw, which are in contact with each other, are called antagonists. In normal occlusion at the tooth has two antagonists. The like teeth of the upper and lower jaw called the principal antagonists, adjacent - side. The like teeth of the left and right jaws differ.
The structure of permanent teeth
Eight cutters are arranged in the middle of the dental arch, four on the upper and lower jaw. Distinguish medial (near the center) and lateral (the sides of them) cutters. The upper central incisors medial or larger than other cutters. The crown has a chisel shape cutters, it is convex to the vestibular surface. The root cutters have one. The lower incisors are less than the upper.
Canines disposed two on each jaw (total of four), the upper lower larger. Crown rhombic shape, the cutting edge in the form of a claw. On the lingual surface of the crown visible edge ridges, separated by a recess. The root of a long, strongly compressed laterally.
The small molars (premolars) are arranged four on each jaw, two on the left and two to the right. The upper premolars are larger lower. The roots of the premolars are usually solitary, but are sometimes divided into two.
Molars (molars) twelve, they are located at six of the top and bottom jaws (three on each side), the third molar called wisdom tooth
Wisdom Tooth - remove and not to suffer
. Large molars have a massive crown and a few roots. Crowns first upper molars rectangular shape with rounded kroyami. Buccal surfaces of molars has four hillocks, separated by a groove, has three roots. The second upper molars are somewhat different from the first, their crowns are compressed and often instead of four cusps on the chewing surface there are only three or even two roots of the second upper molars usually two. Wisdom teeth are variable in shape and size, but they are usually smaller than the first and second molars of the upper and lower wisdom teeth. The most common form of the chewing surfaces of their trehbugorkovaya, has three roots, but sometimes there may be two or even one, fused.
Lower large molars of the upper and lower some have two roots - medial (toward the center) and distal (directed in the opposite direction). Crowns first lower molars rectangular chewing surface comprises five hillocks, three of them - on the buccal side of the crowns and two on the lingual. Second lower molars are cube-shaped crown on the chewing surfaces have four tubercles. The third lower molars (wisdom teeth), as well as the top, very variable in shape and size. They are smaller than the rest of the lower molars, but most of the upper molars. On the chewing surfaces of the crown has four tubercles, sometimes five or three.
All teeth have a good blood supply and innervation, blood vessels and nerves are located in the pulp and periodontal.
The structure of each tooth is different from the structure of other teeth, and it must take into account the treatment, disposal and prosthetics
Fundamentals of prosthetics - not just for the elderly