PRIMARY OR MILK TEETH
primary teeth
Humans usually have 20 primary (deciduous or "baby") teeth and 32 permanent (adult) teeth. Teeth are classified as incisors, canines,premolars, and molars.
Incisors are primarily used for biting pieces from foods such as raw carrots or apples and peeled but uncut bananas, while molars are used primarily for grinding foods after they are already in bite size pieces inside the mouth.
Primary teeth Among deciduous (primary) teeth, ten are found in the maxilla (upper jaw) and ten in the mandible (lower jaw), for a total of 20. There are two types of incisors - centrals and laterals, and two types of molars - first and second. All primary teeth are normally later replaced with their permanent counterparts.
Primary teeth guide the path of eruption of the permanent teeth. So its important to retain the primary teeth until the permanent teeth erupts. If it is lost before the permanent teeth erupts the child may require preventive or interceptive orthodontic treatment to ensure the permanent dentition erupts well into place.
Incisors are primarily used for biting pieces from foods such as raw carrots or apples and peeled but uncut bananas, while molars are used primarily for grinding foods after they are already in bite size pieces inside the mouth.
Primary teeth Among deciduous (primary) teeth, ten are found in the maxilla (upper jaw) and ten in the mandible (lower jaw), for a total of 20. There are two types of incisors - centrals and laterals, and two types of molars - first and second. All primary teeth are normally later replaced with their permanent counterparts.
Primary teeth guide the path of eruption of the permanent teeth. So its important to retain the primary teeth until the permanent teeth erupts. If it is lost before the permanent teeth erupts the child may require preventive or interceptive orthodontic treatment to ensure the permanent dentition erupts well into place.
Permanent Teeth
Permanent teeth (or adult teeth) came after the series of primary teeth and are normally intended to remain in the mouth for the whole lifetime. There are 32 adult teeth, including eightincisors, four canines, eight premolars and twelve molars (with four wisdom teeth). The premolars replace primary molars, while the adult molars appear in a posterior position in the dental arch, not replacing any primary teeth.
The substitution of teeth begins around the age of 6 and happens in a gradual manner. The child is then in a mixed dentition period which lasts several years. Around the age of 12, all adult teeth should have replaced primary teeth. The third molars, or wisdom teeth, complete their development at approximately 18 years, but they might never come out and stay impacted.
The eruption of a tooth can be thwarted by the lack of space, which creates dental crowding ormalocclusion. This condition can be treated with orthodontics.
Sometimes there is agenesis of one or more permanent teeth, which means that the tooth never develops. This happens particularly with wisdom teeth, but also sometimes with incisors or premolars. In some agenesis situations, the corresponding primary tooth does not fall and remains present in the mouth. which can also be managed by consultation with orthodontist.
The substitution of teeth begins around the age of 6 and happens in a gradual manner. The child is then in a mixed dentition period which lasts several years. Around the age of 12, all adult teeth should have replaced primary teeth. The third molars, or wisdom teeth, complete their development at approximately 18 years, but they might never come out and stay impacted.
The eruption of a tooth can be thwarted by the lack of space, which creates dental crowding ormalocclusion. This condition can be treated with orthodontics.
Sometimes there is agenesis of one or more permanent teeth, which means that the tooth never develops. This happens particularly with wisdom teeth, but also sometimes with incisors or premolars. In some agenesis situations, the corresponding primary tooth does not fall and remains present in the mouth. which can also be managed by consultation with orthodontist.
PARTS OF A TOOTH
The anatomic crown of a tooth is the area covered in enamel above the cementoenamel junction (CEJ). The majority of the crown is composed of dentin (dentine) with the pulp chamber in the center. The crown is within bone before eruption. After eruption, it is almost always visible.
The anatomic root is found below the CEJ and is covered with cementum. As with the crown, dentin composes most of the root, which normally have pulp canals.
A tooth may have multiple roots or just one root (single-rooted teeth). Canines and most premolars, except for maxillary first premolars, usually have one root. Maxillary first premolars and mandibular molars usually have two roots. Maxillary molars usually have three roots. Additional roots are referred to as supernumerary roots.
Enamel is the hardest and most highly mineralized substance of the body. It is one of the four major tissues which make up the tooth, along with dentin, cementum, and dental pulp. It is normally visible and must be supported by underlying dentin.
Dentin is the substance between enamel or cementum and the pulp chamber. It is secreted by the odontoblasts of the dental pulp. Dentin is a mineralized connective tissue with an organic matrix of collagenous proteins. Dentin has microscopic channels, called dentinal tubules, which radiate outward through the dentin from the pulp cavity to the exterior cementum or enamel border.
Cementum is a specialized bone like substance covering the root of a tooth. The principal role of cementum is to serve as a medium by which the periodontal ligaments can attach to the tooth for stability.
The dental pulp is the central part of the tooth filled with soft connective tissue. This tissue contains blood vessels and nerves that enter the tooth from a hole at the apex of the root.
The anatomic root is found below the CEJ and is covered with cementum. As with the crown, dentin composes most of the root, which normally have pulp canals.
A tooth may have multiple roots or just one root (single-rooted teeth). Canines and most premolars, except for maxillary first premolars, usually have one root. Maxillary first premolars and mandibular molars usually have two roots. Maxillary molars usually have three roots. Additional roots are referred to as supernumerary roots.
Enamel is the hardest and most highly mineralized substance of the body. It is one of the four major tissues which make up the tooth, along with dentin, cementum, and dental pulp. It is normally visible and must be supported by underlying dentin.
Dentin is the substance between enamel or cementum and the pulp chamber. It is secreted by the odontoblasts of the dental pulp. Dentin is a mineralized connective tissue with an organic matrix of collagenous proteins. Dentin has microscopic channels, called dentinal tubules, which radiate outward through the dentin from the pulp cavity to the exterior cementum or enamel border.
Cementum is a specialized bone like substance covering the root of a tooth. The principal role of cementum is to serve as a medium by which the periodontal ligaments can attach to the tooth for stability.
The dental pulp is the central part of the tooth filled with soft connective tissue. This tissue contains blood vessels and nerves that enter the tooth from a hole at the apex of the root.