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HISTOLOGY: TOOTH DEVELOPMENT FINAL ACTUAL
ASSESSMENT EXAM WITH STRUCTURED
QUESTIONS AND CORRECT VERIFIED ANSWERS
ALREADY GRADED A+
Odontogenesis begins ____ weeks in utero - CORRECT ANSWER >>> 6 Odontogenesis begins in _________ _______ region and progresses _________ - CORRECT ANSWER >>> mandibular anterior posteriorly Odontogenesis begins with a band of ________ covering the ________ **- CORRECT ANSWER
** epithelium stomodeum Epithelium in the stomodeum thickens and becomes an epithelial structure known as the ____________ - CORRECT ANSWER >>> primary dental lamina what is the first sign of tooth development? - CORRECT ANSWER >>> formation of the primary dental lamina Dental lamina grows down into underlying ___________ in __ maxillary and __ mandibular spots - CORRECT ANSWER >>> mesenchyme, 10, 10
What are the spots of dental lamina that grow into the underlying mesenchyme? - CORRECT ANSWER >>> tooth buds/germ small clumps of cells with the ability to form tooth tissues - CORRECT ANSWER >>> tooth buds/germ How many embryonic tissues make up tooth germ? What are they? **- CORRECT ANSWER
** 2: ectoderm and ectomesenchyme tissue from the dental lamina; is from oral epithelium - CORRECT ANSWER >>> ectoderm tissue that forms enamel - CORRECT ANSWER >>> ectoderm tissue from neural crest cells - CORRECT ANSWER >>> ectomesenchyme underlies ectoderm; it is a specialized connective tissue **- CORRECT ANSWER ** ectomesenchyme parts of the tooth germ - CORRECT ANSWER >>> enamel organ dental papilla dental sac forms enamel; from ectoderm - CORRECT ANSWER >>> enamel organ forms dentin & pulp; from mesenchyme - CORRECT ANSWER >>> dental papilla
Stage of enamel organ development in which the dental papilla if formed, enamel organ has 2 layers, and the vestibular lamina appears - CORRECT ANSWER >>> Cap stage (2nd) Stage of enamel organ development which includes formation of hard tissues, four layered enamel organ, form of crown is determined, and the bud of the permanent tooth forms; there is also morpho- and cytodifferentiation - CORRECT ANSWER >>> Bell stage (3rd) What word refers to having two sets of teeth? - CORRECT ANSWER >>> Diphyodont are all deciduous and the permanent molars; come from the primary dental lamina - CORRECT ANSWER >>> antecedent teeth are all permanent teeth EXCEPT the molars; come from the successional/secondary dental lamina - CORRECT ANSWER >>> succedaneous teeth The secondary dental lamina arises from the _______ side of the primary tooth enamel organ. - CORRECT ANSWER >>> lingual Four layers of the Enamel Organ - CORRECT ANSWER >>> Outer Enamel Epithelium (OEE) Stellate Reticulum (SR) Stratum Intermedium (SI) Inner Enamel Epithelium (IEE)
What layer of the enamel organ has cuboidal cells, protective function, direct connection with basal layer of epithelium, and organizes a network of capillaries that will bring nutrition to the ameloblasts? - CORRECT ANSWER >>> OEE What layer of the enamel organ consists of a loose network of epithelial cells resembling connective tissue cells, makes up the bulk of the enamel organ, transmits nutrients to SI, and acts as a cushion for the IEE? - CORRECT ANSWER >>> stellate reticulum What layer of the enamel organ is made up of packed, flattened epithelial cells and helps provide nourishment for the IEE? - CORRECT ANSWER >>> stratum intermedium What layer of the enamel organ has a single layer of columnar epithelial cells, is next to the dental papilla separated by a basement membrane (future DEJ), and is continuous with the OEE? - CORRECT ANSWER >>> IEE What layer of cells will become ameloblasts and is responsible for actual enamel formation? - CORRECT ANSWER >>> IEE An area where the OEE and IEE meet at the most apical edge **- CORRECT ANSWER
** cervical loop Future area of the CEJ - CORRECT ANSWER >>> cervical loop The end of the cervical loop is where the _______ begins - CORRECT ANSWER >>> root sheath (HERS) T/F Enamel forms before dentin - CORRECT ANSWER >>> FALSE Dentin forms before enamel
2nd: fibroblasts 3rd: odontoblasts What is the organic matrix that forms around the dentinal fibers **- CORRECT ANSWER
** dentin (not yet calcified) After some dentin is formed, the dental papilla area is now called the _____. - CORRECT ANSWER >>> pulp Odontoblasts send chemical messages to the _________ to start forming enamel. - CORRECT ANSWER >>> ameloblasts Enamel: is formed from what type of embryonic tissue? is considered what tissue type? is formed from what tooth formation structure? - CORRECT ANSWER >>> embryonic tissue: ectoderm tissue type: epithelium formed from: enamel organ Dentin and pulp:
are formed from what type of embryonic tissue? are considered what tissue type? are formed from what tooth formation structure? - CORRECT ANSWER >>> embryonic tissue: mesenchyme tissue type: connective tissue formed from: dental papilla PDL, cementum, & alveolar bone: are formed from what type of embryonic tissue? are considered what tissue type? are formed from what tooth formation structure? - CORRECT ANSWER >>> embryonic tissue: mesenchyme tissue type: connective tissue formed from: dental sac What is the most common relationship between enamel and cementum at the CEJ? Why? - CORRECT ANSWER >>> cementum overlapping enamel
band of nonkeratinized SSE around the cervical portion of all teeth acting as an attachment mechanism uniting epithelium with tooth structure - CORRECT ANSWER >>> JE Protects tooth from the surrounding CT, if it disintegrates too soon, the tooth will get caught and stick to the connective tissue - CORRECT ANSWER >>> REE interaction between embryonic cells; the effect one cell has on another **- CORRECT ANSWER
** induction when tooth bud forms - CORRECT ANSWER >>> initiation cells multiply enamel organ forms controlled growth - CORRECT ANSWER >>> proliferation specialization of cells into odontoblasts and ameloblasts **- CORRECT ANSWER ** histodifferentiation or cytodifferentiation cells line up at DEJ and CEJ to outline future root and crown; forms shape - CORRECT ANSWER >>> morphodifferentiation deposition of enamel and dentin matrix in incremental layers (on outside) - CORRECT ANSWER >>> apposition growth from deep within - CORRECT ANSWER >>> interstitial
growth to correct size, function, and form (overlapping of differentiation starts in embryonic period and continues until the last tooth is developed - CORRECT ANSWER >>> maturation hardening of the matrix by deposition of calcium salts - CORRECT ANSWER >>> calcification movement of a tooth into the oral cavity - CORRECT ANSWER >>> eruption wearing of occlusal and interproximal contacts during function **- CORRECT ANSWER
** attrition epithelial attachment migrates apically; gingiva recedes - CORRECT ANSWER >>> passive eruption Stages of Eruption - CORRECT ANSWER >>> 1: pre-eruptive 2: pre-functional (active) or passive eruptive 3: post-eruptive/functional (active) stage of eruption up to crown formation - CORRECT ANSWER >>> pre-eruptive stage of eruption that begins when the crown is formed; from developmental position and root formation to functional occlusion - CORRECT ANSWER >>> pre-functional (active)
2: growth of root & root sheath 3: expansion of dental papilla and pulp 4: growth of the PDL and dental sac *** (*** = most likely) The expansion of the dental papilla and pulp results in increased ________ pressures, especially at the ____; the tooth moves from an area of _________ pressure to __________ pressure. - CORRECT ANSWER >>> vascular, apex increased-->decreased The growth of the PDL and dental sac cause _______ ________; then the PDL fibers reorient and help pull the tooth ___ via cell _________. - CORRECT ANSWER >>> ligament traction up, proliferation Eruption of the permanent dentition begins at the time the _____ is completed and the _____ starts to form. - CORRECT ANSWER >>> crown....root Eruption of the permanent dentition continues throughout the life of the tooth by addition of ________. - CORRECT ANSWER >>> cementum The root sheath shapes the ____, not the _____ of the root. - CORRECT ANSWER >>> DCJ (dentocemental junction)
outside As the tooth grows after eruption, the _____ end maintains its approximate position. - CORRECT ANSWER >>> apical At functional occlusion, ____ of root dentin and a little cervical cementum is formed. - CORRECT ANSWER >>> 2/ After the functional stage of eruption, what parts of the tooth are formed? How long may this last? - CORRECT ANSWER >>> rest of root apical foramen most of cementum PDL lamina dura 1.5-4 years The tooth erupts at the same rate as the development of ______ **- CORRECT ANSWER
** HERS Eruption of permanent anterior teeth begins _____ to the corresponding primary teeth. - CORRECT ANSWER >>> lingual During formation and eruption, premolars move _________ and ________, and they develop between the _____ ______ of the deciduous teeth. - CORRECT ANSWER >>> horizontally & occlusally flared roots
Rotation Occlusal Horizontal/lateral Changes in position of the developing tooth rely on growth of: - CORRECT ANSWER >>> teeth alveolar process jaws Retained primary teeth may be the result of: - CORRECT ANSWER >>> no permanent tooth germ formed ankylosis ectopic eruption of permanent tooth premature loss of adjacent tooth submerged/embedded tooth impaction fusion of cementum to bone - CORRECT ANSWER >>> ankylosis
permanent tooth doesn't erupt in its normal position - CORRECT ANSWER >>> ectopic eruption mechanical obstruction of tooth eruption - CORRECT ANSWER >>> impaction In mixed dentition, spaces in deciduous teeth are caused by _________. **- CORRECT ANSWER
** growth of jaw What happens with premature loss of a deciduous tooth? - CORRECT ANSWER >>> normal jaw growth may not take place: 1 side develops differently Why does one side of the jaw develop differently when a primary tooth is prematurely lost? - CORRECT ANSWER >>> chewing only on 1 side chewing side stimulates bone growth only on that side Problems with mixed dentition - CORRECT ANSWER >>> retained root tips permanent tooth impactions midline diastimas submerged/impacted primary teeth ectopic eruption
Sulcular epithelium can become _____________ if it is exposed to the oral cavity or if normal bacterial flora is eliminated. - CORRECT ANSWER >>> parakeratinized Sulcular epithelium attaches to the tooth at the _______ portion of the JE. - CORRECT ANSWER >>> coronal Histologically the base of the gingival sulcus is formed by the ______. It is ___ to ___ cells thick where in joins the sulcular epithelium and tapers down to ___ to ___ cells thick at the apical end. - CORRECT ANSWER >>> JE 15 - 20 1 - 2 What is the difference between sulcular epithelium of normal and periodontally involved JE tissues? - CORRECT ANSWER >>> ulceration The inner part of the JE is attached to the tooth via the ______ lamina by _________. - CORRECT ANSWER >>> basal hemidesmosomes The hemidesmosomes attach to the lamina _____ of the basal lamina, and the lamina _____ of the basal lamina is next to the enamel. - CORRECT ANSWER >>> lucida densa
Attachment is reinforced by _______ ______ which brace the marginal gingiva against the tooth. - CORRECT ANSWER >>> gingival fibers Average length of JE - CORRECT ANSWER >>> .25-1.35mm Final product of ameloblasts after enamel matrix formation - CORRECT ANSWER >>> primary enamel cuticle an acellular, noncalcified excess basal lamina protective layer that covers the crown and is seen on newly erupted teeth - CORRECT ANSWER >>> primary enamel cuticle a thin coating worn off due to frictional forces of mastication or brushing **- CORRECT ANSWER
** primary enamel cuticle The primary enamel cuticle possibly causes _____ or _____ stain on newly erupted teeth - CORRECT ANSWER >>> green or yellow What is sometimes referred to as "Nasmyth's membrane"? - CORRECT ANSWER >>> primary enamel cuticle What joins gingival epithelium after eruption and forms the JE? - CORRECT ANSWER >>> REE Put these layers in order from most external to most internal: primary enamel cuticle, enamel, REE - CORRECT ANSWER >>> REE Primary enamel cuticle (acts as glue) Enamel
