L4: Introduction to periodontal tissues in health and disease- Link with Prosthodontics Flashcards
What is the Periodontium?
Collective term describing tooth supporting tissues including:
- the root cementum
- periodontal ligament
- alveolar bone
- gingiva
These tissues develop and function as a unit, along with the formation of the tooth roots and tooth eruption
When do the first signs of tooth development appear?
First signs of tooth development around 6th week (thickening of the oral epithelium)
What is the tooth germ?
Where does it derive from?
The tooth germ is an aggregation of cells derived from the ectoderm of the first pharyngeal arch and the ectomesenchyme of the neural crest
Which are the three parts in which tooth germ is organized in?
- Enamel organ: enamel and primary epithelial attachment
- Dental papilla: pulp and dentin
- Dental follicle: cementum, periodontal ligament, alveolar bone
What is gingiva?
The part of the oral mucosa covering the tooth-bearing part of the alveolar bone and the cervical neck of the tooth
Why is gingiva of major significance?
Major peripheral defense against microbial infections and mechanical trauma
What kind of function does gingiva have?
The gingiva has sensory function
What receptors is gingiva well innervated with?
it is well innervated with pain, touch and temperature receptors
What is gingiva anatomically divided into?
It is divided anatomically into attached, marginal and interdental components
What is attached gingiva demarcated by?
by gingival groove & mucogingival junction
Where is attached gingiva bound to?
Firm, resilient, tightly bound to the underlying periosteum of alveolar bone
What epithelium is attached gingiva covered by?
Covered by keratinized epithelium
Where is the width of attached gingiva greatest?
Width is greatest over buccal surface of maxillary incisors and narrows over buccal surface of mandibular premolars
Where is free gingiva attached to?
Delicately attached to the tooth surface
What does free gingiva cover?
It covers about 1-1.5 mm of tooth surface
What does free gingiva surround?
It surrounds the cervical part of the teeth and is separated from the teeth by a fine space called gingival sulcus
What is gingival sulcus?
- Shallow crevice/space around the teeth bounded by the tooth on one side and the sulcular epithelium on the other side
- The coronal extent of the gingival sulcus in the gingival margin
- it is V shaped
What is gingival zenith?
The most apical point of the marginal gingival scallop is called the gingival zenith
What is the biological width?
Dimension of soft tissue which is attached to the portion of the tooth coronal to the crest of alveolar bone
What does the interdental papilla occupy?
Occupies the gingival embrasure, which is the inter proximal space beneath the area of tooth contact
- Can be pyramidal or have a col shape
What is col?
Col is a valley like depression that connects a facial and lingual papilla
What does the shape of interdental papilla depend on?
The shape of the interdental gingiva depends on the contact point between the two adjacent teeth
What can the pigmentation be?
- Exogenous
- Endogenous
What is GCF?
- Serum transudate or inflammatory exudate
- can be found in the crevice
Where does GCF arise from?
Arises from the gingival plexus of blood vessels in the gingival corium, subjacent to the epithelium lining the dentogingival space
What is GCF a mixture of?
Mixture of molecules originating from blood, host tissues and subgingival plaque
What is Cementum?
- Avascular mineralized tissue covering the root surface
- It begins at the cervical portion of the tooth at the CEJ and continues to the apex
- Less hard than dentin
- Very permeable
Which are the main functions of cementum?
- anchorage -> medium for attachment to the collagen fibres of PDL
- repair/resorption -> continuous deposition thus it repairs the damages
- protection (fluoride) -> seal for open dentinal tubules
What is the periodontal ligament?
Soft specialized connective tissue situated between the cementum and the bone socket wall
Where does the periodontal ligament extend coronally up to?
It extends coronally up to the most apical part of the connective tissue of the gingiva
Which is the width of the periodontal ligament?
Width 100-400 micron (decreases with age; thinnest portion around the middle third of the root)
Which are the main functions of periodontal ligament?
- supportive
- sensory/proprioception
- formative o protective
- regeneration/wound healing
- nutritive
What is the alveolar bone?
- The specialized bone structure that contains the sockets of the teeth and supports the teeth
- Develops from the dental follicle
What does the alveolar bone consist of?
- Alveolar process/supporting alveolar bone (maxilla and mandible)
- Alveolar bone proper (bundle bone and Sharpey’s fibers)
Which are the main functions of the Alveolar bone?
- Anchorage
- Protection and support for teeth
- Bone synthesis
- Absorbs and distributes forces (e.g. occlusal pressure generated from tooth contacts or ortho movement)
What is the alveolar process continuous with?
Alveolar process is continuous with basal bone of maxilla and mandible
Cortical bone:
- similar to cortical/compact bone anywhere else in the body
- extends both on the lingual/palatal and buccal side
- thicker in mandible vs. maxilla
- cortical bone generally greater in the lingual/palatal vs. buccal side
- hierarchical structure, where the fundamental units are represented by osteons (Harversian system)
Cancellous bone:
- similar to cancellous/spongy bone anywhere else in the body
- honeycomb structure
- Network of thin highly connected trabecular containing bone marrow
Alveolar bone proper/bundle bone:
- Continuation of the cortical plate, it lines the tooth socket
- Surrounds the root of the teeth
- It gives attachment to the principal fibers of PDL
- It is a specialized type of compact bone composed of bundle bone and Haversian bone
- Called bundle bone as numerous bundles of Sharpey’s fibers pass into it from the PDL
What is a periodontal disease?
It is a chronic multifactorial inflammatory disease
- initiated by bacterial microorganisms and
- characterized by a severe chronic inflammation that leads to progressive destruction of the tooth supporting apparatus, tooth loss and eventually to masticatory dysfunction
What is necessary to cause periodontitis?
A pathogenic biofilm is necessary but not sufficient to cause periodontitis
What percentage is the inflammatory-immune response estimated to account for, regarding the risk of periodontal tissue damage?
The inflammatory-immune response is estimated to account for almost 80% of the risk of periodontal tissue damage
What is Plaque Induced Gingivitis?
Inflammation of the gums due to plaque accumulation
Which are the clinical characteristics of Plaque Induced Gingivitis?
- Erythema
- Edema
- Tenderness
- Enlargement
- Swelling
- Redness
What happens upon probing in the situation of Plaque Induced Gingivitis?
Bleeding on probing
Which are the clinical observations of Plaque Induced Gingivitis?
- Bleeding on probing
- No bone loss
- REVERSIBLE
What is Periodontitis caused by?
Supra and sub gingival plaque/calculus accumulation
Which are the clinical characteristics of Periodontitis?
erythema, edema, tenderness, enlargement, swelling, redness, suppuration, tooth mobility, gum recession, halitosis
Which are the clinical observations of Periodontitis?
- Bleeding on probing
- Loss of periodontal attachment
- IRREVERSIBLE
What can periodontal disease be classified as?
- Gingival pocket
- Periodontal pocket
What is gingival pocket formed by?
formed by gingival enlargement without destruction of the underlying tissues.
Why does the sulcus deepen?
The sulcus deepens because of the increased bulk of the gingiva
What does the periodontal pocket occur with?
it occurs with destruction of supporting periodontal tissues
What can periodontal pocket be?
- supra bony (supracrestal) -> horizontal bone loss and pocket base coronal to the crest of the alveolar bone
- intrabony -> vertical bone loss and pocket base below the crest of the alveolar bone
What can invasion of biologic width lead to?
- Can lead to gingival inflammation
- Can lead to pocket formation
- Can lead to loss of clinical attachment (loss of bone and gum)
How does an active periodontal disease affect the flow of GCF?
Increased flow rate when there is active periodontal disease
How does GCF flow affect prosthodontic procedures?
- Will affect moisture control which is important when trying to restore a tooth or when cementing any fixed prosthesis.
- Nearly all cements are hydrophobic and should be used only when there is good moisture control
