February 27, 2025 Author : Catarina Costa Abreu Human dentition has two main phases throughout life: deciduous dentition and permanent dentition . These phases are fundamental for the development of chewing, speech and smile aesthetics. The development of deciduous teeth (also called milk teeth , baby teeth or temporary teeth) begins during pregnancy. Normally, the eruption of the first teeth occurs between 6 and 10 months of age, and the dentition will be complete around 24 to 30 months. The deciduous dentition is made up of 20 teeth : 8 incisors, 4 canines and 8 molars, following approximately this order of eruption: Central incisors (first the lower ones, then the upper ones); Lateral incisors (first the upper ones, then the lower ones); First molars (first the lower ones, then the upper ones); Canines (first upper, then lower); Second molars (first the lower ones, then the upper ones). The change from deciduous teeth to permanent teeth begins around the age of 6 and ends around the age of 12-13, when all the baby teeth have been replaced by permanent teeth. The permanent dentition is made up of 32 teeth : 8 incisors, 4 canines, 8 premolars and 12 molars (including the third molars, popularly known as wisdom teeth). The eruption of permanent teeth follows approximately this order: First lower and upper molars (these teeth appear behind the second baby molars, without any teeth falling out); Central incisors (first the lower ones, then the upper ones); Lateral incisors (first the lower ones, then the upper ones); Canines (first the lower ones, then the upper ones); First premolars (first the upper ones, then the lower ones); Second premolars (first the upper ones, then the lower ones); Second molars (first the lower ones, then the upper ones); Lower and upper third molars (may not erupt in some people or may need to be extracted due to lack of space or inadequate growth). Function of teeth Incisors : cut food; Canines : hold and tear food; Premolars and molars : crush and grind food. Anatomy of teeth Crown : is the visible part of the tooth, above the gum; Neck : the area where the crown meets the root, close to the gum; Root : the invisible part of the tooth, inserted into the maxillary or mandibular bone, fixed by the periodontal ligament. Teeth structure Enamel : the outermost layer of the tooth surface, being the hardest and most mineralized tissue in the entire human body. It protects teeth against wear and cavities; Dentin : intermediate layer, where the dentinal tubules are located, which can transmit sensations to the nerve; Pulp : the innermost layer, where the nerves and blood vessels are located, responsible for the nutrition and sensitivity of the tooth. In addition to these layers, the tooth root is covered by a layer called dental cement, which helps to fix the tooth to the alveolar bone, through the periodontal ligament. Sources Tim Wright J. Anatomy and development of the teeth. www.uptodate.com Meet the dentistry clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
