Dental Anatomy and Occlusion

Lecture 1: oral cavity, dental anatomy and morphology nomenclature

  • maxilla: upper jaw that doesnt move

  • mandible: lower jaw, only freely moving part of the skull

  • labial: The lips

  • palatine raphe is the seam that runs along the hard palate

  • glossal is tongue

  • pharyngeal is throuat

  • retromolar pad the pad behind last molar

  • pterygomandibular raphae for injections

  • Lingual is tongue

  • Frenum soft tissue attachment

  • diastema is a gap between teeth

  • tubercle, soft tissue, tiny projections

  • buccal refers to cheek

  • mucosa is the pink tissue lining the cheek

  • vestibule is the dead space

    • buccal vestibule

  • between the space of teeth and cheek is the buccal corridor

  • narrow buccal corridor is a wide smile (Preferred)

  • wide buccal corridor is a narrow smile

  • gingical sulcus is the space popcorn kernal gets stuck here

    • 1-3 mm is good

  • gingival margin is where the teeth and gum meet, arch

alveolar: teeth attached to the bone

  • Periodontal ligament: what holds the tooth in the head

    • the tooth is suspended by ligaments

    • attach root of tooth to bone

    • alveolar crest fibers

    • horizontal fibers

    • oblique fibers

      • actively resisting the forces of chewing

    • apical fibers

      • located in the bottom third of the root

    • interradicular: located only between roots of multirooted teeth, not every tooth has it,

    • Transseptal: exists between teeth, connects one tooth to another


  • Tissues of tooth

    • Enamel: protective external surface layer

      • highly calcified

    • cemento is the enamel of the root surface, covers the root surface

    • Pulp

      • exists in the root canal

      • it’s alive,

      • dentil-producing cells (odontoblasts) produce dentin throughout the life of a tooth

    • cementoenamel junction

      • runs around the waist of the tooth

      • junction between enamel cocvering and


  • surfaces of teeth

    • Outer surfaces

      • facial surface

        • surface towards teh face

      • buccal surface

        • facial surface of posterior cheek

        • premolars and molars

      • Labial surface

        • facial surface of anterior teeth (lips)

  • Towards the gums

    • Gingival

      • towards the

    • Cervical


  • Marginal ridge

    • occur on the outside of teeth

    • Mesial and distal

  • Mamelons and perikymata

    • mamelons, small bulges of tubercles on the incisal edges of newly erupted permanent incisors

    • Perikymata

      • numerous, minute horizontal ridges on the enamel of newly erupted permanent teeth

        • wear away from toothbrushing, eating, abrasion things


Valleys

  • Sulcus

    • broad v-shaped depression on the occlusal surface of each posterior teeth running mesiodistally between the buccal and lingual cusps

  • Groove

    • channel running at the very base of the sulcus,

    • Central

      • separates

  • crests of curvature and height of contour are the same thing


Embrasures

  • spaces around each contact area

  • lingual embrasure is the largest

Furcations

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Lecture 2: Anterior Teeth

  • Taper: gradual narrowing

  • concave: having an outline or surface that curves inward

  • convex:

  • proximal view means either mesial or distal

  • certical line is the curve

  • cervical line: mesial and distal surface, curved incisaly


The Incisors: Function

  • cut food

  • enable articulate speech

  • incisor root has a distal defelction, slight bent at the tip of the root

  • all inciso

  • maxillary central incisor root doesn’t have distal defelction

    • maxillary central incisor has the poorest root to crown ratio

  • maxillary lateral incisor root has a distal defelction at the apex

  • mandibular lateral incisor

Canines

    the mandibular canine often considered the longest crown in the mouth ( along with the maxillary central incisor)

mesial aspect of crown is flat and continuous with the mesial aspect of the root, one continuous line


Posterior Teeth

  • The Posteriors: General Classification

    • All posterior teeth have cusps

    • all have transverse ridges

    • occlusally means higher up

  • Maxillary 1st premolar

    • buccal cusp tip offset to the distal, everything else is mesial.

    • only premolar which as 2 roots

    • incisocervically refers to just the crown, from the incisal surface to the gingival margin (cervical third)

  • Maxillary 2nd premolar

    • the smaller the central groove, the wider the mesial and distal marginal ridge.

  • Mandibular 1st premolar

    • distal marginal ridge is more occlusally oriented than the mesial marginal ridge,

    • tilt noticeably toward the lingual surface at the cervix

    • contact and marginal ridge are more occulsal on distal

  • Mandibular 2nd Premolar

    • cup tips are more rounded

    • cusp tips are offset to mesial

    • Types

      • 4 lobes: U or H shaped Groove

      • 5 Lobes: Y shaped groove (most common)

        • one giant buccal cusp and 2 smaller lingual cusps (mesial lingual is bigger an distal bucal)

        • They do not have transverse ridge

  • more special in mesial half of first premolar

  • maxillary second premolar

  • 5 lobes = 3 cusps

  • 4 lobes = 2 cusps

  • mandibular first molar, which as 5 cusps

    • develops from 5 lobes


The Molars Lecture

  • the root trunk: gets longer as you travel posteriorly

  • Maxillary molars

    • 3 roots: trifurcation

      • mesil buccal, distal buccal, and palatal

    • wider buccal-lingual than mesial distal

  • Mandibular molars

    • pentagonal in shape

    • wider mesiodistal than buccallingual

    • 2 roots

    • longest root to crown ratio

  • Maxillary 1st molar

    • widest mesiodistally in maxillary arch

    • widest facial lingually in the dentition

    • Cusp of carabelli seen on its lingual surface of Mesial lingual cusp    

      • does not develop from lobe

  • Mandibular 1st molar

    • widest faciolingually in the mandibular arch (the widest of all ficiolingual is the maxillary first molar

    • mesial root is longest of any molar with greatese faciolingual dimension of any tooth

  • maxillary third molars (typically not asked, but good to know)

    • are the shortest of all permanent teeth


Root Anatomy and Pulp Morphology

  • root furcation = space between the roots

    • bifurcation = 2 roots

    • trifurcation = 3 roots

    • F

  • Pulp cavity = pulp chamber + root canals

    • orfice is the opening/path from pulp chamber to root (pulp) canals

  • Pulp horns

    • incisors generally have 3 pulp horns

      • exception is the maxillary (peg) lateral, 1 pulp horn

    • cusped teeth (canines, premoals, molars) have one pulp horn under each functional cusp

    • pronounced in the teeth of younger people

  • Accessory (lateral) canal, chemical irrigation used to reach (disinfecting the area)

    • most often located in the apical third of the root

  • Types of Canal configurations

    • Type 1 just one canal

    • Type 2: two canals that combine in to one apically, single root

    • type 3: two separate canals

    • type 4: single canal, but

  • Anterior Teeth

    • all have one root, except the mandibular canine, which is most likely to have 2 roots (facial and lingual)

  • Premolars

    • Maxillary first premolars

      • if it has 3 roots, the third is usually

  • Molars

    • Maxillary moalrs

      • most often have 3 roots and 4 canals

        • two canals in the mesiobuccal root

          • more likley in maxillary first molar

      • Third molars: usually have 3 canals

        • considerable variation in root formation

  • Triangles are shown to account for the root horns when accessing the roots.

  • we see oval access, a canine has one pulp horn

  • ovals in premolars, when there are two cusps, its in the buccal lingual formation


Principles of Digital Dentistry

  • Intraoral scanners Advantages

    • reduce patient discomfort

    • time efficient

      • can “add” to a scan, no need to redo

      • eliminates shipping time to lab

    • Enhanced diagnostics

      • better visualization and planning

      • early detection of dental issues

    • Eliminates impression materials and stone models

    • allows better communication with lab

    • Accuracy

      • 9 microns

      • no material distortion

    • Versatility

      • Pt education

  • Addititive manuafacturing

    • you take an intraoral scan you and send it to a 3d scanner that will add material in small increments that will give you the object ( 3d model, etc.)

  • Subtractive Manufacturing

    • take digital impression, subtracts the parts you don’t want , grinds around

  • Intraoral scanners work

    • project light to area being scanned and the light will bounce off the object and hit back at the sensor (capture reflections by imaging sensors

    • Mirrors are widely used to increase the measuing area of a single view (multiple angles)


Operative Dentistry

  • Dental Caries

    • preventable

    • chronic infectious disease

    • biofilm-mediated

  • Cavity (hole)

    • used to describe a caries lesion that had progressed to the point that there was a breach in the surface integrity of the tooth

  • Drill, use Prepare

  • Fill, use Restore

  • GV Black noticed carious lesions were not random

    • caries repeated developed in predictable anatomical locations

    • Pit-and-fissures lesion in places hard to clean

    • Smooth-surface lesions occured proximally and cervically

  • GV black caries classification

    • Class 1: Pit and fissure

    • Class 2: proximal surface of posterior teeth, always has 2 distinctions

      • smooth surface caries

      • two distinctions mesial/distal and occlusal

      • mesial occlusal, distal occlusal, medial occlusal distal

      • happens at/below contact point

    • Class 3: proximal surfaces of anterior teeth

      • does not involve incisal edge

      • smooth surface caires

      • Classify based on mesial/distal, and has lingual/facial

    • Class 4: same as class 3 but includes the incisal edge, commonly seen in fractures

    • Class 5: gingival third of the crown, facial or lingual surface of all teeth

    • Class 6: incisal edge of anterior teeth or the occlusal cusp tips of posterior teeth

      • not common

  • all classes are smooth surface caries except for class 1

  • The cavity preparation became specifically engineered with certain mechanical properties

    • cavosurface finish: finishing enamel walls and margins

  • “Extension beyound prevention” prepare (drill) beyond the decay to prevent spread of caries.

    • for GV Black: Preparation = disease + tooth anatomy + material requirements + prevention

  • Cariology: study of caries as a disease, not simply a defect requiring surgical removal

  • Classic GV Black

    • prep with properties to hold and maintain the restoration

    • “extension for prevention”

  • Modified GV Black

    • similar shape but preserve as much natural tooth structure as possible

    • prevents tooth fracture

  • Contemporary

    • remove decay and restore with a resin-based restoration (i.e. composite)

  • Modern Operative Dentistry: Tooth preparation

    • 1. conserve as much healthy tooth structure as possible

    • 2. remove all defects while simultaneously providing protection of the pulp-dentin complex

    • 3. form the tooth preparation

    • 4. allow for esthetic placement of a restorative material where indicated

    • FActors that dictate preparation include:

  • iatrogenic damage: damaging harm to teeth, surrounding tissues accidentally

  • 9 steps of cavity preparations

    • 1. Outline Form

    • 2. Resistance Form (primary)

      • the shape and placement of the preparation of the walls and floors, comes from smooth flat floors that helps resistance

      • line angles should be rounded and not 90 degrees

      • forces oritned parallel to long axis

    • •3. Retention Form (primary)

      • to retain your restoration, hold it in place

      • result of tipping forces or lifting (forces oriented at an angle to the long axis)

      • Comes from walls

      • Amalgam macro-mechanical retentsion, dont make the walls straight, make it cone shaped

      • compositive can be put of straight walls

      • • 4. Convenience Form

        • is the shape or form that provides adequate observation, accessibility, and ease in the preparation, caries removal, and restoration of the tooth

      • 5. Removal of Decay


          • 6. Pulpal Protection (if needed)

            • dentin provides little protection

            • avoid over desiccating and over drying the dentin

          • 7. Secondary resistance and retention form

            • come from other things that are not the floor or wall

            • slots and pins

          • 8. External wall (cavosurface) finishing

          •     cavosurface finishing, (margination), and finishing external preparation walls all mean the same thing

          • allows the creation

          • unsupported enamel is weak, make sure the enamel is covered by dentin

          • make sure all enamel walls that form a 90 degree exit angle with the cavosurface

            • 9. Debridement

            • cleaning of the tooth preparation using air/water syring

  • Handpieces (not drill)

    • High speed

      • must always be used with water

      • friction grip burs

    • Slow speed

      • for caries excavation and finishing

      • latch grip burs (or friction grip burs)

        • forward- caries excavation

        • reverse - smoothing and polishing

      • motor, contra angle, nose cone

  • Carbide Burs

    • have cutting etch

    • round is for excavating decay

    • come in high speed and slow speed

    • 1556 high speed

    • RA 56 low speed

  • Diamond Burs

    • used to cut teeth

    • comes in different grits

    • coarse grits used to remove bulks

    • fine grits for finishing and crown preparations


Operative Dentistry 2

  • 3.8mm sink halfway your about at 2mm

  • class 2

    • broken gingival contact

      • that is where the decay happens

      • at or below the contact point

    • open facial and lingual embrasures 0.25mm

      • measured with tine of explorer

    • axial depth is the distance between gingival floor and axial wall

      • premolar 1mm

      • molar 1.5mm

      • axial wall should be convex or follows contour of gingical cavo-surface margin or straight

    • axial pulpal line angle should be rounded (line that forms when axial wall and pulpal floor meet

    • broken gingival contact is when the two adjacent teeth are no longer touching

      • you should be able to pass your explorer

      • The proximal box is centered on contact area because the contact area is centered

      • S curve = extreme facial contact in the maxillary premolars, MO surface


  • Class 2 Tools and Procedures

    • Interproximal guard is the curvy guard

  • Class 3

    • facial or lingual, lingual 90% of the time

    • outline form is a rectangular shape

    • mesial and distally you don’t cross the marginal ridge

    • you wnat your preperation to interuupt the triangle (in order to know that you have broken gingival contact)

    • unsupported enamel on facial wall is acceptable since susceptability for fracture is low

    • you want everything at 90°

    • 330 bur (pear shaped)

  • Class V (5)

    • shape of the outline form is directly proportional to the mesio-distal diameter of the tooth, with the outline following the contour of the cementoenamel junction

    • prep will be in the middle 2 quarters (middle half)

    • in the incisal half of prep, 1.5mm (because the incisal half is thicker than the gingival half)

    • gingival half prep needs to 1mm

    • a bevel is a softening of the prepared cavosurface margin (softening to 45°)

      • exposing more enamel for bonding

      • Only bevel for composite restoration

      • Only bevel on enamel

        • Diamond burs

      • Don’t bevel for Amalgam

    • 1556 carbide bur

  • Rubber Dam

    • mandatory for all bonded restoration because bonded restorations do not cure in the presence of moistures

    • Isolation strategies

      • Anterior isolation (class 3, 4, 5)

        • first premolar to first molar; use 2 clamps

    • 2 pieces of foss in each hole and tie to ligate clamps to the rubber dam frame

  • Other methods of controlling the operating field

    • drugs

      • antisialogogues: not routinely used for operative procedures

      • epinephrin

    • dri-angles (bibulous paper)


    • Cotton rolls

    • vacuum devices

  • Place the rubber clamp below the height of contour to prevent it from flying out

  • the bow should be faced towards the posterior, face the throat/back of the mouth

bring marker and mirror for friday as well as rubber day stuff

tuesday: learners blocks, white yellow red (on tuesday)

bring handpieces and all of your burs