Oral Histology and Anatomy

• Minor salivary glands are present in the submucosa of the oral cavity, except in the gingiva and the anterior part of the hard palate.
• Tertiary dentine is formed after carious stimuli.
• The parotid gland is correctly paired with Stenson's duct.
• The secretion of salivary glands depends upon nerves.
• Korff fibers are found in developing dentin of teeth.
• The smallest duct of the salivary glands is the Rivinus duct.
• Successional teeth arise from the successional lamina.
• The lateral part of the dental lamina gives rise to the vestibular lamina.
• Circumvallate papillae are 10 in number.
• The hard palate is innervated by the greater palatine nerve and the nasopalatine nerve, both branches of the maxillary division of the trigeminal nerve (CN V).
• Mucoperiosteum belongs to the hard palate.
• Neural crest cells give rise to dentine, cartilage, and bone.
• Disturbance in morpho differentiation leads to a change in the size and shape of the tooth.
• The parotid gland is a purely serous salivary gland.
• Muscularis mucosa is excluded from the components present in the oral mucosa.

Tooth Development EMQ

• Nondividing cells that determine the location and number of cusps are enamel knots
• During the bell stage, the dental lamina disintegrates to form enamel pearls
• Histological and morphological differentiation occur in the bell stage
• In the bell stage, ameloblasts are formed from the inner enamel epithelium
• Epithelial rests of Malassez are disintegrated fragments of Hertwig's root sheath
• The ectodermal cells of the bud of the tooth develop into the enamel organ

Tooth Morphology

• The root completion of permanent teeth is achieved after 2 to 3 years of eruption
• Mandibular central incisors are small incisors in permanent dentition
• According to the Universal numbering system:
  • The right maxillary central incisor is 11.
  • The right 2nd mandibular molar is 31.
  • The left mandibular canine is 33.
  • The Left maxillary 1st premolar is 24.
• The general crown size of a permanent maxillary central incisor is larger than any other anterior tooth.
• Mamelons are rounded elevations on the incisal edge of newly erupted incisors and are present on incisal edges of newly erupted incisors.
• The developmental groove is defined as a sharp linear depression separating lobes.
• Sulcus is the valley on the occlusal surface of posterior teeth.
• The maxillary permanent teeth sequence of eruption is: 61234578
• The second premolar is the permanent tooth that erupts into the space previously held by the primary second molar.
• Maxillary incisors have slightly rounded distoincisal angles.
• From mesial aspects, the shape of the maxillary central incisor is triangular.
• The mesial contact area of the permanent maxillary lateral incisor is located at the center of the incisal third.
• Root completion of permanent teeth is achieved after 2 years of eruption of the crown.
• In incisor teeth, except the mandibular central incisor, the mesial incisal slope is longer than the distal incisal slope.
• The prismless layer of enamel is found near the amelodentinal junction.
• The mucogingival junction is the junction of attached gingiva and alveolar mucosa.
• Enamel is composed of 96% minerals and 4% organic materials and water.
• Hypocalcified areas in enamel are enamel tufts.
• Enamel prisms of the cusp tip pass in a twisted course.
• Hunter-Schreger bands reflect periodic changes in the prism direction of enamel.
• The rod sheath is less calcified than the enamel rod.
• The presence of predentine is the stimulus that initiates the actual formation of the enamel matrix.
• Enamel is 96% inorganic, 1% organic, and 3% water by weight.
• Masticatory mucosa excludes non-keratinized tissue epithelium.
• Masticatory mucosa continuously transverse palate.
• The mucosa of the dorsal surface of the tongue is specialized mucosa.
• Fungiform papillae do not have a white surface which is poorly keratinized.
• Hydroxyapatite is the major inorganic constituent of enamel by weight.
• The deciduous central incisor is usually the first dental (enamel) organ to develop.
• The parotid gland duct opens into the oral cavity as a papilla opposite the maxillary second molar.
• Wharton's duct is the duct of the submandibular gland.
• The glossopharyngeal nerve is the parasympathetic nerve that mainly supplies the parotid gland.
• Minor salivary glands are present in the submucosa of the oral cavity, except in the gingiva and the hard part of the hard palate.
• Sublingual glands begin to develop at 8 to 12 weeks during embryonic life.
• Secretory end pieces that are composed of serous cells are typically spherical.
• Secretory end pieces that are composed of mucous cells typically have tubular configuration.
• Intercalated ducts of the salivary gland are numerous and long in purely serous glands.
• Saliva is neutralized due to bicarbonates.
• The largest amount of saliva is produced by the submandibular gland.
• A mucocele is the problem in a duct of minor salivary glands with pooling of saliva in tissues.
• Perikymata seen on facial surfaces of canines are a result of normal development.
• The nutritional supply of ameloblasts during most of their life cycle is from the stellate reticulum.
• The enamel of posterior teeth is thickest at the occlusal surface.
• Loss of reduced epithelium before eruption leads to the prevention of the development of a secondary enamel cuticle.

EMQs on Embryonic Development

• Time of onset of calcification of deciduous maxillary central incisors: 6 months in utero.
• Time of completion of crowns of permanent mandibular central incisors: 4-5 years.
• Time of eruption of permanent maxillary central incisors: 7-8 years.
• Time of eruption of permanent mandibular lateral incisors: 7-8 years.
• Time of completion of roots of permanent maxillary lateral incisors: 11 years.