LO 4 Flashcards
The lining of the oral cavity is referred to as the _____ or ______
- Oral mucosa
- Mucous membrane
The oral mucosa is a stratified squamous epithelial lining that runs from the ______ posteriorly to the area of the _______
- Margins of the lips
- Tonsils
What are the three categories of oral mucosa?
- Specialized mucosa- on the upper surface or dorsum of the tongue and is adapted to accommodate for the sensation of taste
- Masticatory mucosa - comprises the gingiva and hard palette tissue, it undergoes trauma or compression during mastication
- Lining mucosa - all other areas of oral mucosa
Describe masticatory mucosa
- It is the mucosa of the gingiva and hard palate
- It is firmly attached
- Parakeratinized or keratinized epithelium
- Pressure of food on this tissue causes it to become parakeratinized or keratinized
_____ mucosa is designed to withstand frictional forces such as swallowing and chewing
Masticatory mucosa
Describe lining mucosa
- It is loosely attached
- Non-keratinized epithelium
- Examples are the mucosa covering the lips, cheeks, floor of the mouth, inferior surface of the tongue, soft palate, uvula, and alveolar mucosa
Describe keratinization
- The process by which epithelial cells differentiate or mature
- Begin as basal cells and travel through layers of epithelial cells to the outermost layer
- The more keratinized and epithelial cell is the more resistant and tough it is
Surface layer of dead cells without nuclei such as on the hard palate are _______
Keratinized
If the surface layer has some dead cells without nuclei and some dying cells with flattened nuclei it is ______
Parakeratinized
If the surface layer all tends to have nuclei that appear fairly healthy and normal such as on alveolar mucosa it is _______
Non keratinized
What does the periodontum consist of?
The periodontal tissues that support and surround the teeth
What are the two divisions of the periodontum?
- The gingival unit
- The attachment unit
What is the gingival unit comprised of?
- Free gingiva(gingival margin)
- Interdental papilla
- Attached gingiva
- Alveolar mucosa
Describe free gingiva
- Extends from the gingival margin to the base of the gingival sulcus
- Usually light pink in color
- Averages between 0.5 to 2 mm in depth
- Located next to the enamel about 0.5 to 2 mm coronal to the CEJ
- Forms a collar, separated from the tooth by the gingival sulcus
This structure fits closely around the tooth but it’s not directly attached to it and can be stretched away from the tooth surface with a periodontal probe
Free gingiva
Describe the interdental papilla (gingival papilla)
- The free gingival located in the triangular interdental spaces
- In interior teeth, the Apex is sharp, but more blunt in the posterior teeth
- Two interdental papilla per set of teeth, one facial and one lingual
- Lateral borders and tip are formed by free gingiva well the center portion is formed by attached gingiva
- When inflamed, it takes on a color that is more red than normal and exhibits a puffy appearance with some blunting of its apex
Describe the gingival sulcus
- The spaces between the free gingiva and the tooth surface
- The inner portion of the gingival sulcus is non keratinized
- The outer portion is the free gingiva which is keratinized
- Attached gingiva begins at the base of the gingival sulcus
Want a gingival sulcus is deep and unhealthy it is termed a _______
A _______ often occurs on the outside of the free gingiva corresponding to the shape of the base of the sulcus
Gingival groove
Healthy depth for gingival sulcus is approximately _______ when measured with a probe
1-3 mm
Describe the junctional epithelium
- Attaches the sulcus (gingiva) to the tooth
- Approximately 1 to 2 mm in length
- Forms a color around the neck of the tooth
- Non-keratinized stratified squamous epithelium, making it more permeable to fluids, bacteria, and toxins
Describe attached gingiva
- Extends apically from the base of the sulcus and is attached to the Bone by collagenous fibers
- Stippled texture resembling dimpled surface like an orange peel
- Keratinized
- Covered by stratified squamous epithelium
- Color of the gingiva ranges from light to dark pink
- May contain pigment (melanin pigmentation)
Describe alveolar mucosa
- Joins the attached gingiva at the mucogingival junction and is continuous with the rest of the tissue to the vestibule
- Tissue is thin and soft
- Loosely attached to the underlying bone
- Composed of lining mucosa
- Smooth, thin, and non-keratinized
What three things is the attachment unit comprised of?
- Cementum
- Alveolar bone
- Periodontal ligament
**The function is not only supportive, but also nutritive (through nerves and blood vessels), formative (to replace the cementum, periodontal ligament and alveolar bone) and sensory (senses pain)
________ is a layer of hard mineralized tissue that covers the root of the tooth and anchors the ends of the periodontal ligament fibers to the tooth, and without it the tooth would fall out of its socket
Cementum
The ______ if cementum protects the underlying dentin and seals the ends of the open dentinal tubules
Outer layer
Cementum can be ______ or _______
- Cellular - cementoblasts become embedded in the cementum
- Acellular - no embedded cementoblasts
Cementum is formed by ______
Cementoblasts
Acellular cementum always covers the ______ and sometimes extends over almost all of the ______ except the ______
- Cervical 1/3 of the root
- Root
- Apical portion
Cellular cementum covers the ______ portion of the root and sometimes may form over ______
- Apical
- Acellular cementum
Cellular cementum is like ______ in character and in the way in which it grows and resorbs
Bone
Cementum grows by the _______ of new layers on top of one another
Apposition (really means addition)
Changes in ______ and ______ influence the growth activity of cementum
- Function
- Pressure
______ Are the embedded ends of connective tissue fibers of the periodontal membrane. Some are embedded in ______ and some are in ______
- Sharpey’s fibers
- Cementum (both cellular and acellular)
- Bone
The type of bone that lines the sockets in which the roots of teeth are held is called ________
Alveolar bone proper
Describe alveolar bone
- Bone that lines the socket in which roots of the teeth are held
- Thin, compact, many small openings through which blood vessels, nerves, and lymphatic vessels pass
The socket in which the tooth rests is called the ______ which provides support and protection for the roots of the teeth
Alveolus
The alveolar bone proper and the alveolus are part of the ______ that surrounds and supports the teeth in the maxilla and mandible
Alveolar process
Describe the composition of alveolar bone
- Composed of compact or cortical bone and spongy bone
- Compact bone is the outside wall of the alveolar bone, where the periodontal ligament fibers are anchored and the rich vascular supply penetrates
- Spongy bone is the interior of the alveolar bone
- It can increase and decrease in response to physical pressure, function, and bacterial infection and inflammation
The _______ is the portion of the alveolar bone located between the teeth; it varies in ______ and ______ depending on the tooth position
- Alveolar crest
- Size
- Shape
Describe periodontal ligaments
- A fibrous connective tissue that surrounds it attaches the tooth roots to the alveolar bone
- Collagen fibers inserted into the cementum prevent tooth mobility by anchoring the tooth into its alveolar socket
- PDL is connected to cementum and bone by collagen fibers called Sharpey’s fibers
- Forms and maintains fibrous and calcified tissue; provides nutritional transport and senses pain
The fibers of the periodontal ligament are arranged in the following five groups
- Alveolar crest group - fibers extending from the cervical area of the tooth to the alveolar crest
- Horizontal group - fibers running horizontally from the tooth to the alveolar bone
- Oblique group - fibers running obliquely from the cementum to the Bone
- Apical group - fibers radiating apically from the tooth to the bone
- Interradicular group - periodontal fibers between roots of multiroted teeth
The arrangement of fibers in the periodontal ligament prevents the tooth from being ______
Pushed into the bone (creates a nice hammock)
Periodontal ligament fibers also ______ the tooth and bone, minimizing the trauma of being pushed together
Insulate
Periodontal ligament fibers are constantly being subjected to a variety of pressures exerted on the tooth, therefore is constantly undergoing _______
Functional change
The periodontal ligament allows _____ movement within the bony cavity
A small degree (suspension)
The ability of the periodontal ligament to expand allows the tooth to ________
Tip, rotate, or be compressed within the bony cavity
Describe some of the forces that exert pressure on the teeth
- Active eruption - tooth eruption into the oral cavity and eruption to compensate for occlusal abrasion
- Mesial drift - the musical movement of molars to compensate for proximal abrasion
- Masticatory occlusal forces - tooth occlusion during chewing
- Orthodontic corrective forces - a dentist or orthodontist placing pressure causing appliances on the teeth to correct malocclusion
- Traumatic occlusal forces - teeth being subjected to premature contact during occlusion
