Oral Cavity Development and Dental Anatomy Vocabulary

Vocabulary flashcards covering human embryology, maxillofacial development, odontogenesis, dental eruption, nomenclature systems, and occlusion principles based on the lecture material.

Human Embryology

The study of prenatal development from fertilization to birth, divided into the ovular period (weeks $1$ to $3$), embryonic period (weeks $4$ to $8$), and fetal period (weeks $9$ to $36$).

Fertilization

The union of two haploid gametes (a spermatozoon and an ovum) in the Fallopian tube to form a single diploid cell with $46$ chromosomes called a zygote.

Blastomeres

The individual cells produced by the mitotic division (segmentation) of the zygote.

Morula

A mulberry-shaped solid cluster of cells formed by the continued mitotic division and compaction of blastomeres during the first week of development.

Blastocyst

A stage of preembryonic development around day $5$ or $6$ featuring an outer trophoblast, an inner embryoblast, and an internal cavity called the blastocele.

Trophoblast

The outer cell layer of the blastocyst responsible for forming extraembryonic tissues and initiating implantation into the endometrium.

Embryoblast

The inner cell mass of the blastocyst that gives rise to the tissues of the embryo itself.

Bilaminar Embryonic Disc

A two-layered flat disc formed during the second week of development composed of the epiblast (outer layer) and hypoblast (inner layer).

Gastrulation

The developmental process occurring in the third week wherein epiblast cells migrate through the primitive streak to form a trilaminar embryonic disc.

Germ Layers

The three primary cell layers formed during gastrulation—ectoderm, mesoderm, and endoderm—which give rise to all tissues and organs.

Notochord

A mesoderm-derived axial structure that forms the foundation of the future vertebral column and induces the formation of the neural plate in the overlying ectoderm.

Stomodeum

The primitive oral cavity formed between the 3rd and 4th weeks of development, located in the midline between the prosencephalon and the pericardial cavity.

Oropharyngeal Membrane

The embryonic membrane separating the stomodeum from the primitive gut, which ruptures during the 5th week to connect the primitive mouth with the pharynx.

Meckel's Cartilage

A cartilaginous structure in the mandibular process of the first branchial arch that acts as a framework or mold for mandible development.

Branchial Arches

The primary embryological structures involved in the development of the facial complex, neck, nasal cavities, oral cavity, larynx, and pharynx.

Primary Palate

An anterior palatal structure formed between weeks $5$ and $6$ of gestation by the fusion of the medial nasal processes.

Secondary Palate

The main part of the palate formed between weeks $7$ and $8$ by the fusion of the lateral palatine processes arising from the maxillary processes.

Primary Epithelial Band

An epithelial thickening formed at week $6$ along the free margins of the future jaws that divides into the vestibular lamina and dental lamina.

Vestibular Lamina

A derivative of the primary epithelial band that proliferates to form the oral vestibule, including the lips and cheeks.

Dental Lamina

A derivative of the primary epithelial band that produces $20$ epithelial swellings or tooth buds corresponding to the primary teeth.

Enamel Organ

An epithelial component of the tooth germ comprising outer epithelium, inner epithelium, stellate reticulum, and stratum intermedium that forms dental enamel.

Dental Papilla

An ectomesenchymal cell condensation within the tooth germ that acts as the precursor to dentin and dental pulp.

Dental Sac

The surrounding ectomesenchymal tissue of the tooth germ that gives rise to periodontal tissues, including cementum, periodontal ligament, and alveolar bone.

Ameloblasts

Specialized cells derived from inner enamel epithelium responsible for enamel matrix deposition (amelogenesis).

Odontoblasts

Specialized ectomesenchymal cells derived from the dental papilla responsible for dentin formation (dentinogenesis).

Hertwig's Epithelial Root Sheath

An epithelial structure formed at the cervical loop by the fusion of inner and outer enamel epithelia that guides tooth root formation.

Reduced Enamel Epithelium

A protective thin layer covering the crown enamel after amelogenesis is complete, safeguarding the tooth during eruption.

Nolla's Stages

A $10$-stage classification system developed in 1960 to evaluate tooth calcification and eruption progress in permanent teeth.

Space of Nance

The difference in combined mesiodistal length between primary lateral sectors (canines and molars) and permanent successors (canines and premolars), measuring roughly $2.4\,\text{mm}$ in the maxilla and $4.3\,\text{mm}$ in the mandible.

FDI Two-Digit System

A dental notation system where the first digit represents the quadrant ($1\text{--}4$ for permanent, $5\text{--}8$ for primary) and the second digit denotes the tooth position from the central incisor backwards.

Mesial Surface

The proximal surface of a tooth facing toward the midline of the dental arch.

Distal Surface

The proximal surface of a tooth facing away from the midline of the dental arch.

Occlusal Surface

The masticatory surface of posterior teeth (premolars and molars).

Overbite

The vertical distance between the incisal edges of the maxillary and mandibular central incisors, normally ranging from $0\text{--}4\,\text{mm}$.

Overjet

The horizontal distance between the incisal edges of the maxillary and mandibular central incisors, normally ranging from $0\text{--}2\,\text{mm}$.

Curve of Spee

The anteroposterior curvature of the occlusal plane starting at the lower canine cusp and extending along the buccal cusps of premolars and molars.

Curve of Wilson

The frontal curvature of the occlusal plane created by the vestibulolingual inclination of the teeth.

Tooth Structure

The anatomical makeup of a tooth, consisting of enamel, dentin, pulp, gingiva, bone, root, and apex.

Stomatognathic System

An anatomical and functional unit consisting of the maxilla, mandible, teeth, muscles, blood vessels, nerves, and temporomandibular joint (TMJ).