Lectures 7 & 8 Flashcards
Gingiva and alveolar bone
T/F - Gingiva is the part of the oral mucosa which surrounds & is attached to teeth & alveolar bone.
True
Describe Alveolar Mucosa
- translucent & bright pink
- epithelium is thick & non-keratinized
- has a loose submucosa which allows movement, including numerous elastic fibres (as well as collagen)
- has minor salivary glands
- joins attached gingiva at mucogingival junction
- not present on palatal surface of maxillary teeth, attached gingiva blends with palatal mucosa
Describe Attached Gingiva
- whitish, opaque
- epithelium is para or orthokeratinised
- bound firmly to alveolar bone by coarse collagen, sparse elastin
- no minor salivary glands
- may show stippling (due to collagen fibres in lamina propria inserting directly into periosteum)
T/F - mucogingival junction marks the abrupt change in epithelium & composition of lamina propria
True
Describe Free Gingiva
- a fold of mucosa which is not bound to underlying hard tissues
- extends from bottom of gingival sulcus adjacent to tooth to free gingival groove
- free gingival groove, if present, is opposite bottom of gingival sulcus (occurs in about 40% of individuals)
- apex of fold is gingival margin
T/F - gingival sulcus lies between free gingiva & tooth
True
T/F - gingival sulcus should be more than about 2mm deep,
False
Deeper than 2mm of the gingival sulcus is called a ___________ ______ and is considered to be diseased.
Periodontal pocket
T/F - Junctional epithelium is deep to bottom of gingival sulcus to CEJ
True
T/F - junctional epithelium is not bound to underlying tooth
False
T/F - in junctional epithelium, there is slow cell turnover with cells migrating towards the gingival sulcus
False, there is high rapid turnover
In anterior teeth, the interdental tissue forms a pointed elevation called a ________. In posterior teeth with a broader area of contact between adjacent teeth, the interdental tissue forms two peaks on the buccal and lingual sides with an indented central region in between called a ______.
papilla, COL
T/F - Gingival ligament is part of the periodontal ligament and helps maintain the functional integrity of the teeth
False, it is not part of PDL
T/F - Periodontal ligament extends from alveolar crest to apex of tooth
True
T/F - periodontal ligament is connective tissue fibre bundles connecting cementum or alveolar bone to lamina propria of gingiva or binding other fibres in gingiva together
False, it is specialised connective tissue joining anchoring cementum to cribriform plate of alveolus / socket
T/F - gingival ligament is located from the alveolar crest to apex of tooth
False, it’s above alveolar crest
T/F - gingival ligament contains connective tissue fibre bundles connecting cementum or alveolar bone to lamina propria of gingiva
True
List the major fibre groups of the gingival ligament
- Dentogingival
- Circular
- Alveolar gingival
- Dentoperiosteal
- Transseptal
T/F - Dentogingival fibres are the least numerous and stretch from cervical cementum to lamina propria of both free & attached gingiva.
False, they are the most numerous
T/F - circular fibres of gingival ligament encircle tooth as a band, some attaching to cementum or alveolar bone .
True
T/F - circular fibres interlace with other fibres & hold them together & also bind free gingiva to tooth
True
T/F - Alevolar gingival fibres stretch from free gingiva to lamina propria of both free & attached gingiva
False, it stretches from alveolar crest to LP
T/F - Dentoperiosteal fibres stretch from cementum over alveolar crest to insert into periosteum on the inner surface of the alveolar bone
False, outer surface of alveolar bone
T/F - Transseptal fibres stretches from cementum of tooth to cementum of root of adjacent tooth over alveolar crest
True
List the minor fibre groups of gingival ligament
- Longitudinal
- semicircular fibres
- transgingival fibres
- interdental/interpapillary fibres
- vertical
T/F - longitudinal fibres of gingival ligament goes from cervical cementum via gingiva to cementum of same tooth
False, it’s in free gingiva for long distances
T/F - semicircular fibres goes from cervical cementum to gingiva of adjacent tooth
False, it’s in cervical cementum, and travels via gingiva to cementum of same tooth
T/F - Transgingival fibres goes from cervical cementum to gingiva of adjacent tooth
True
T/F - Interdental/interpapillary fibres connect buccal & lingual papillae via interdental gingiva
True
T/F - Vertical fibres of gingival ligament connect alveolar mucosa to free gingiva towards marginal gingiva & interdental papilla
False, it connects from attached gingiva
List the functions of gingival fibres
- stabilising & providing rigidity to gingiva, especially during mastication
- join gingiva to cementum & bone
- circular (& longitudinal fibres) bind the other tissues in place
- stabilise positions of teeth
- experimental evidence - cut labial & gingival fibres following orthodontic repositioning & repositioned teeth are less likely to re-rotate
T/F - Bone is mineralized connective tissue
True
T/F - Bone consists of about 67% mineral in the form of calcium hydroxyapatite while remainder is made of organic matrix & collagen.
True
T/F - osteoblasts, osteocytes, osteoclasts are in bone
True
Anatomical bones consist of a dense outer layer called ______________ & an inner medullary region called ____________ ______________
Compact bone, spongy or cancellous bone.
Compact bone is proportionally ______ bone & ______ soft tissue. It has a mechanical function and has a _____ turnover of components than spongy bone. It may have __________ but these are not marrow cavities (contain fatty connective tissue rather than marrow.)
more, less, low, small connective tissue
Spongy bone consists of bars of bone called _________ plus soft tissue called _______ (containing blood forming tissue). Spongy bone is proportionally _____ bone & more _____ tissue components in spongy bone over more readily than compact bone - calcium store.
trabeculae, marrow, less, soft
Lamellae on the outer surface are arranged parallel to the surface & are called __________________.
outer circumferential lamellae
Layering in the deeper parts of the compact bone consist of a series of cylinders called ____________________ whose walls are formed of a series of concentric layers with a central vascular channel called a _____________.
Osteons or haversian systems, haversian canal
Larger channels carrying blood vessels into the Haversian systems are called ___________
perforating canals or volkmann’s canals
T/F - regions between the Haversian systems are interstitial bone & are the remains of earlier Haversian systems which have been partly broken down.
True
Except in bone when it is first formed, Haversian systems are surrounded by a layer of mineral rich collagen poor bone called a ________
cement line
T/F - trabeculae of spongy bone consists of layers mostly parallel to the surface
True, larger trabeculae may have a few Haversian systems
T/F - Dark cavities in bone contain more dense bone
False, its air
Describe remodelling of bone
First DESTRUCTION of existing bone by osteoclasts (not symmetrical - cuts across existing bone layers)
Then RECONSTRUCTION by osteoblasts. (symmetrical - lays down complete Haversian rings or lamellae
What is periosteum?
specialized connective tissue covering the outside of bone
What does periosteum consist of?
An inner layer adjacent to the surface of the bone with osteoblasts & precusors, small blood vessels plus a small amount of connective tissue & an outer fibrous layer contiguous with adjacent tissue - fascia, muscle
T/F - Endosteum is a lining of osteoblasts on all inner surfaces including marrow spaces & Haversian canals
True
T/F - Bone marrow only has developing blood cells
False, it has variable proportions of developing blood cells, fat cells & a delicate support of reticular fibres & reticular cells
T/F - Osteoblasts are cells that break down bone by means of secreted enzymes
False, they make bone
T/F - When osteoblasts are active, they synthesise both collagen & ground substance (osteoid - unmineralized bone).
True
T/F - Active osteoblasts do not secrete matrix vesicles & enzymes involved in the extracellular mineralization of the matrix
False, they do secrete
T/F - Osteoblasts are stratified and dark staining
False, they are cuboidal
T/F - Osteocytes are surrounded by bone
True
Osteocytes in cavities called _______ with narrow extensions called _______ containing osteocyte processes. _______ interconnect & processes are connected by gap junctions. ______ are easily seen in ground sections.
Lacunae, canaliculi, canaliculi, canaliculi
________ are very large multinucleate cells (derived from blood monocytes like other phagocytic cells), often in shallow troughs on the surface of bone (due to erosion) called _______ _____
Osteoclasts, Howships Lacunae
T/F - howship’s lacunae are frequently seen since bone constantly remodels in response to mechanical stimuli and metabolic needs (calcium store)
True
_________ - bone of the alveolar processes of maxilla & mandible which forms alveoli or sockets of teeth
Alveolar bone
T/F - alveolar bone has cortical compact bone and spongy bone within, and the lining of the alveolus has a fibrous layer
False, the lining of the alveolus lacks a fibrous layer and just has cellular periosteum
Compact bone lining the alveolus has ________ because it is perforated by foramina transmitting numerous blood vessels & nerves.
Cribriform plate
Compact bone lining the alveolus has _______ beacuse it contains the terminal ends of the periodontal fibres
Bundle bone , PDL are sharpey’s fibres
Compact bone lining alveolus has name ________ because it is particularly opaque to X-rays (appears as a white line).
Lamina dura
T/F - Orthodontic tooth movement relies on differentiation of odontoblasts & resorption of bone on the pressure side
True
Orthodontic tooth movement needs remodelling of ______ on the opposite (tension) side & __________ on the socket wall.
collagen, bone deposition
Orthodontic tooth movement: _______ is much more resistant to pressure induced changes & although there is evidence of a minor amount of ______ _____ this seems to be followed by rapid repair
cementum, root resorption
