Pulp, cementum, supporting tissues ( m1 pt. 2)

DEJ is scalloped, the concavity is? the convexity?

Dentin, enamel

Striae of Retzius

Incremental rings that represent variations in deposition of the enamel matrix during tooth formation

Striae of Retzius extend frim DEJ to enamel surface, ending in shallow furrows known as?

Perikymata/Imbrication Lines

Pulp conforms to the shape of the?

Tooth

Pulp

-varies in contour and size among various teeth in the same mouth

The PULP \____ in size with advancing age, it becomes more fibrous and may contain \_____

-decrease in size
-pulp stones and denticles
*Radiographs are used in determining size of pulp cavity and any existing pathologies

Functions of the pulp

formative, sensory, nutritive, defensive

Formative/Developmental

production of primary and secondary dentin by odontoblasts

Nutritive

supplies nutriments and moisture to dentin through the blood vascular supply to the odontoblasts and their processes

Sensory/Protective

through the sensory nerve fibers

Defensive/Reparative

response to irritation forming replacement odontoblasts laying down reparative dentin

Is there reparative dentin formed in mild irritation , ex. Proper tooth prep?

No, which explains pulpal problems following tooth prep and restoration

Cementum

covers the root of the tooth
-avascular
-light yellow and slightly lighter in color than dentin
-slightly softer than dentin
-Permeable to a variety of materials

Cementum thickness can increase at the \___ bcs?

Root end of tooth, to compensate for attritional wear of the occlusal/incisal surface and passive eruption of the tooth

During physiologic tooth movement, \_____ of the apical portion of the root happens

Resorption

Cementum is formed by

cementoblasts(from undifferentiated mesenchymal cells in CT of dental follicle)

Which has the highest fluoride content of all the mineralized tissues?

Cementum

Cementum is formed \_____

Thruout life
-Capable of repairing itself to a limited degree

Cementum composition

45-50% inorganic(hydroxyapatite)
50-55% organic and water(collagen and protein polysaccharides)

Coronal pulp

Portion of pulp in the crown

Radicular pulp

Pulp located in the root area of tooth

Disease of the pulp

1. Hyperemia
2. Reverse pulpitis
3. Irreversible pulpitis
4 necrosis

Hyperemia

-pulp has increased blood flow and volume within the chamber
-causing momentary pain that stops at once

Reversible pulpitis

Inflammation of the pulp
-pain happens for a few secs and once stimulus is gone, pain stops

Reversible pulpitis treatment

Restoration is possible

Irreversible pulpitis

Pain spontaneously comes with no irritant
-when there is irritant, pain is worse
-pain lingers more than 15 secs

Irreversible pulpitis treatment

RCT

Necrosis

Spontaneous continuous throbbing pain
-Pain is caused by heat, relieved by cold
-Later no response to stimuli

Irreversible pulpitis treatment

root canal or extraction

physiologic tooth movement

movement of teeth due to non-pathologic processes, such as thru the PDL which is elastic\=mobile

Sharpey's fibers

principal fibers of the periodontal ligament embedded in both the cementum and the alveolar bone to attach the tooth to the alveolus

2 types of cementum

acellular and cellular

Acellular cementum

living tissues without cells
-on the coronal half of the tooth

Cellular cementum

On Apical half

CEJ (cementoenamel junction)

Where enamel of crown and cementum of root meet, also called cervical line
*removing cementum (can be caused by Abrasion, erosion, caries, scaling and procedures for finishing and polishing) may cause sensitivity in this area

Function of tooth

Mastication, esthetic, speech, protection of supporting tissues

Mastication

normal tooth form and proper alignment ensures efficiency of the various tooth classes

Esthetics

Form and alignment of anterioris

Speech

form and alignment of both anterior and posterior teeth assist in articulation of certain sound

Protection of supporting tissues

form and alignment of teeth in the dental arches assists in the development and protection of the gingival tissues and alveolar bone

Contour

Convexity and concavity of teeth
-located at the cervical 3rd of the crown on the facial surfaces of all teeth and lingual surfaces of incisors and canines
-middle third of crowns on lingual of posteriors

Contour function

helps with protection and stimulation of the supporting tissues during mastication.

Contour clinical significance

Normal tooth contours act in deflecting food and stimulates the investing tissues
-know normal contour as that's what you'll replace, don't overcontour or undercontour

Overcontour

results in inadequate stimulation

Undercontour

results in trauma to the tissues

proximal height of contour provide:

1. Contacts with the proximal surfaces of adjacent
teeth preventing food impaction
2. Adequate embrasure space gingivaly for the gingival tissue, supporting bone, blood vessels and nerves.

contact area

where the proximal surfaces of adjacent teeth touch
-needed bcs it helps support each teeth, bcs tooth is mobile, it needs support from contact

Embrasure

-V-shaped spaces originating in the proximal areas between adjacent teeth
-Incisal or occlusal, gingival, facial or buccal and lingual embrasures
Filled by papilla preventing food entrapment; triangular between anteriors; and shaped like a mountain range in the posterior

Embrasure clinical significance

•Correct relationship of embrasure, cusp to suici, marginal ridges and grooves of adjacent and opposing teeth provide for the escape of food from the occlusal during mastication

What is the clinical significance if embrasure is too large?

Too large embrasure- food is forced into interproximal space by opposing cusp

What is the clinical significance if embrasure is too little/absent?

Too litte or absence of embrasure- additional stress is created in the leeth and supporting structures during mastication

correct anatomic form in restoring clinical significance

-renders the teeth more self-cleansing because of the smoothly rounded contours that are more exposed to the cleansing action of foods and fluids and the frictional movement of the tongue, lips and cheeks.

What happens when there is Failure to understand and adhere to correct anatomic form in the performance of restorative procedures

can contribute to the breakdown of the stomatognathic system.

Proximal contact area

-incisal 3rd of the approximating surfaces of the maxillary and mandibular central incisors
-From incisor proceeding posteriorly, these contacts progressively becomes cervically positioned, resulting into larger incisal or occlusal embrasures

Proximal contact area clinical significance

Restorative procedures require maintenance of correct proximal contact relationships between teeth which results in correct embrasure form.

Cusps

are blunt, rounded, or pointed projections of the crowns of teeth

Developmental grooves

separates cusps; central groove separates buccal and lingual cusps

Fossae

depressions between cusps

Fissure

grooves that have noncoalesced enamel

Pit

non-coalesced enamel on the deepest point of a fossa.

Marginal ridges

elevated rounded ridges located on the mesial and distal edges of the tooth's occlusal surface

Marginal ridge(clinical significance?)

Marginal ridges of adjacent posterior teeth should be at the same height

Maxilla and mandible composition

65% inorganic (hydroxyapatite)
35% organic (type I collagen)

Supporting bone is composed of

1 Cortical plates - (buccal and lingual wails of the socket) composed of compact bone
2 Spongy base- fills the areas between the plates

PDL clinical significance

The margin of a tooth should not be positioned subgingivally unless dictated by caries, previous restoration, esthetics or other preparation needs.

Maxilla(and pre-maxilla)

forms the upper jaw, major portion of the hard palate, boundaries of the orbit, and sides and base of the nasal cavity. It has the alveolar processes that contains the teeth.

Mandible

forms the lower jaw; is horseshoe shaped;
attached to the skull via the TMJ.
It has the following parts: body (horizontal) the superior border comprise the alveolus; ramus (vertical) the superior border are the coronoid and the condyle.

Oral Mucosa

Mucous membrane that covers all oral structures except the clinical crowns of teeth

Oral mucosa 2 layers

2 lstratified squamous epithelium and lamina propia

Functional types(oral mucosa)

1. masticatory- composed of free and attached gingiva and mucosa of hard palate
2, Keratinized epithelium
3, Thick lamina propia- connected to the cementum and periosteum of alveolar process

Lining or reflective mucosa: thin movable lissue

1, Covers the inside of the lips, cheek, vestibule, lateral surface of the alveolar process (except mucosa of hard palate), floor of the mouth, solt palate, and Inferior surface of the tongue
2. Thick nonkeratinized epithelium
3. Thin lamina propia
4. Mucogingival junction - comprise of lining mucosa and masticatory mucosa

Oral mucosa directly affected by restoration(clinical significance?)

Ex. Gingival mucosa - make sure resto is smooth so it wont be irritated

Alveolar mucosa

Thin, soft tissue loosely attached to the alveolar bone
Covered by a thin, nonkeratinized epithelial layer
Submucosa contains loosely arranged collagen fibers, elastic tissue, fat and muscle tissue
Delineated from the attached gingiva by the mucogingival junction

Periodontium

-hard and soft tissues that invest and support the teeth
-Connective tissue structure
-Stratified squamous epithelium
-Attaches the teeth to the maxilla and mandible
-Support the teeth during function

Periodontium has 2 mineralized and 2 fibrous CT

2 mineralized CT: alveolar bone, cementum
2 fibrous CT: PDL, lamina propia

Periodontium is divided into

Gingival unit, attachment apparatus

Gingival unit

free gingiva, attached gingiva, alveolar mucosa

Attachment apparatus

cementum, periodontal ligament, alveolar bone

Free gingiva

from the marginal crest to the level of the base of the gingival sulcus

Gingival sulcus

space between the free gingiva and the tooth surface

interdental papilla

outer aspect of free gingiva in each gingival embrasure

Free gingival groove

shallow groove parallel to the marginal crest of the free gingiva; it indicates the level of the base of the sulcus

Attached gingiva

composed of dense connective tissue that attaches it firmly to the cementum and periosteum of the alveolar bone
extends from the depth of the sulcus (free gingival groove) to the mucogingival junction

Periodontal Ligament (PDL)

-Complex soft, connective tissue
- Contains numerous cells, blood vessels, nerves and extracellular substances fibers(collagen)and ground substances(proteins and polysaccharides)

PDL function

1. Attachment and support
2. Sensory
3. Nutritive
4. Homeostatic

Attachment and support(PDL function)

principal fibers attach cementum to alveolar bone and serves a cushion to suspend and support the teeth

Sensory(PDL function)

Provided by nerve supply

Nutritive(PDL function)

blood vessels supply the attachment apparatus with nutritive substances

Homeostatic(PDL function)

specialized cells of the ligament function to resorb and replace the cementum, periodontal ligament and alveolar bone

Cementum

hard tissue with intercellular substance covering the anatomic roots of teeth.

Alveolar process

thin compact bone with many small openings through which blood vessels, lymphatics and nerves pass.
Forms, supports and lines the sockets into the which the roots of the teeth fit.

Alveolar bone proper

inner wall of the socket where the periodontal ligaments are attached

Supporting alveolar bone

-surrounds the alveolar bone proper supports the socket

Static occlusal relationship

contact between teeth when the jaw is closed and stationary

dynamic occlusal relationship

Tooth contact during mandibular movement

Occlusion clinical significance

Design of the restored to surface can have important effects on the number and location of occlusal contacts and must take into consideration static and dynamic relationships

Angle's classification of occlusion

Class I, II, III occlusion

Class I Occlusion

the MB cusp of the maxillary 1st molar occludes with the MB groove of mandibular 1st molar.

Class II occlusion

MB cusp of max first molar contacts buccal embrasure between mand 1st M and mand 1st PM

Class III Occlusion

MB of max 1st molar fits into DB groove of mand 1st molar