M3 - Lesson 1 Histologic Structures Involved in Jacket Crown and Fixed Bridge Fabrication

Histological Structures of the Dental Tissues Groups of Dental Tissues:

Calcified Tissues- these are the hard tissues/structures of the oral cavity

• enamel

• dentin

• cementum

• alveolar bone

enamel

• It is composed primarily of carbonate substituted hydroxyapatite crystallites. The process of enamel development is called amelogenesis and the cells that create enamel, the ameloblasts, are derived from oral ectoderm.

dentin

• is the main supporting structure of the tooth and is the second hardest tissue in the body after enamel.

• It is 70% mineral and acellular, as hydroxyapatite crystals, and 30% organic as water, collagen and mucopolysaccharide.

Cementum

• is a hard layer of tissue that helps the periodontal ligament attach firmly to a tooth. Made of cementoblasts, cementum slowly forms over a lifetime. Cementum is a hard, calcified layer of tissue that covers the root of the tooth.

Alveolar bone

• consists of four layers. In addition to the three layers found in all bones, namely periosteum, dense compact bone and cancellous bone, there is a fourth layer called the cribriform plate, which lines the alveolar sockets. Radiographically, this appears as a fine radiodense line called the lamina dura.

   

Non-calcified Tissues - these are the soft tissues of the oral cavity

Pulp

• is a mass of connective tissue that resides within the center of the tooth, directly beneath the layer of dentin. Referred to as part of the “dentin-pulp” complex, and also known as the endodontium, these two tissues are closely interrelated and dependent on each other's development and survival.

Periodontal ligaments

• is a soft connective tissue embedded between the cementum and the inner wall of the alveolar bone socket to help support teeth. The periodontal ligament harbors a small population of stem cells that are responsible for maintaining and repairing periodontal ligament tissues and function.

Gingiva

• - is the tissue that surrounds and protects the teeth and underlying bone. The gingiva is attached to the tooth, forming a seal that protects the underlying bone and helps provide a barrier against infection.