Final Exam Anatomy Primary dentition, TMJ, and Occlusion

Symptoms of TMD

-Biting chewing difficulty -clicking popping or grating when opening -Dull aching or pain in face - earache (morning) -Headache (morning) -Hearing loss -Migrane (morning) -Jaw pain or tenderness -tinnitus -neck and shoulder pain

Treatment of TMD

-Reversible treatment such as over the counter medicine -jaw streching or relaxation excercises -occlusal splint (mouthguard) -Long term approaches: Reconstructive dentistry Mandibular repositioning splints Joint replacement

TMJ disorder (TMD)

-can affect many other joints of the body

Myofunctional considerations-lingual frenum

Another issue is the length of the lingual frenulum. If the lingual frenulum is restricted, as with ankyloglossia, it limits the possibility of creating appropriate pressure against the maxillary arch for normal expansion. can be corrected

tooth abrasion

Typically located around the cementoenamel junction (CEJ)

Overbite (vertical overlap)

Vertical aspect of the overhang measured in milometers (slight, moderate, severe) (1/3, 1/2, completely cover)

attrition

a wearing down over time

curve of spee and wilson can be lost with __ bc of __

age, attrition

protrusive occlusion

all centrals and laterals of both arches are in contact mandible pushed forward

Class 1 (Angles Classification)

also called neutral occlusion classified by left and right canine and molar relationship -canine and molars are lined up well, but something else is wrong. (canine needs to sit between mand canine and 1st premolar) (mesiobuccal cusp of max molar comes down into mesiobuccal groove of mand molar) ex: midline shift, slight crowding, version normal profile is called mesognathic discrepancy includes: open bite bc anteriors do not touch

Temporal bone (zygomatic process) consists of

articulating eminence and articular fossa

Mandible consists of

articulating surface of condyle (articulates w temporal bone)

retraction of mandible

bringing backward of the lower jaw

thumb and finger sucking/ pacifier use

can cause excessive overjet, overstrech lips, pushes up on palate causing it to be tall

Phase 4 of arch development

canines erupt, arch is completed from first molar forward -second molars start to erupt

Joint Capsle

completely encloses TMJ. Has 2 layers

Primary incisors

each arch has 4 both permanent and primary have same arch, position, function, and general shape we see extensive wear of incisal edges caused from bruxism. Usually grow out of this

outer layer of joint capsule

firm, fibrous connective tissue supported by surrounding ligaments

Movements of TMJ

gliding- allows jaw to move forward or backward rotational- either have depression or elevation of mandible (lower portion movement) exursion- normal movement of mandible during function

Overjet (horizontal overlap)

how much horizontal overlap is there between maxillary

Malocclusion

lack of ideal form in dentition while in centric occlusion (mandible as far back as can go) -if teeth aren't lined up has negative esthetic appearance, difficulty with oral hygiene -80% kids and teens have malocclusion -most common type is crowding -overjet (buck teeth) second most common

Abfraction

loss of tooth surface in cervical area

synovial fluid

lubricates, provides nutrition to disk, and fills joint

First primary tooth to erupt

mandibular central incisor (6-10 months)

lateral occlusion

movement that occurs when moving the mandible right or left until the canines are in a cusp-to-cusp relationship used when trying to access a posterior tooth or giving anesthesia

arch development phase 3

permanent premolars erupt -leeway space-Space created when primary molars are shed to make room for smaller mesiodistal permanent premolars -space maintainer may be necessary if second molars erupt before premolars

articular fossa

posterior to articular eminence, depression on inferior aspect of temporal bone

Normal (centric) occlusion

rarely exists also called habitual occlusion voluntary position of dentition that allows maximum contact when teeth occlude

occlusion

relationship between maxillary and mandibular arch, and teeth in same arch

lateral deviation of the mandible

shifting of the lower jaw to one side

centric stops

the three areas of centric contacts between the 2 arches, which include height of cusp contour, marginal ridges, and central fossae

Inner layer of joint capsule

thin, lined with synovial fluid consisting of thin connective tissue that contains nerves and blood vessels

Articular disk of TMJ

-composed of fibrocartilaginous tissue (like ear) -positioned between two bones that form the joint -disk divides each joint into 2 compartments (synovial cavities) -Lower portion: lower disk and mandible provide rotational movement (initial movement of mouth when the jaw first opens) -Upper portion: formed by articular disk and temporal bone provide translational movements (secondary gliding motion of jaw as it widely opens)

arch development phase 2:

-eruption of permanent anterior teeth near midline -permanent location not established until arch form completed

Phases of arch development Phase 1:

-permanent molars first erupt -primate spaces (spaces between primary teeth) still present, allows for permanent teeth to come in

what is proper alignment of occlusion important for??

1. so saliva can properly flow over teeth, which cleanses from decay 2. So teeth are spread out forces of occlusion and not too much on one area. if not spread out can have occlusal trauma

Primary Canines

2 in each arch (4) resemble permanent canines

in centric occlusion, each tooth in the arch comes in contact with..

2 teeth in opposite arch exception is central incisors and third molars (equals forces in dentition)

How many years does it take for complete eruption of the mouth

2-3 years (6 month delay is normal, order of teeth is of more concern)

Class 3 (Angles Classification)

Also called Mesioclussion side profile called: prognathic Mandible is more forward than should be. Mandibular incisors are in front of maxillary Canine: Canine is more back over the premolars Molar: Mesiobuccal cusp of maxillary first molar is further distal onto mandibular first molar

Class 2 (Angles Classification)

Also called distocclusion -mandible is back farther than it should be -canine relationship: maxillary canine is found in front of mandibular canine or mesial portion of canine -molar relationship: mesiobuccal cusp of first molar has moved and is toward mesiobuccal cusp of mand molar

Protrusion of the mandible

Bringing the lower jaw forward

Clinical considerations of Primary Teeth

Convey how valuable primary teeth are Oral hygiene practices must be supervised- if not taken care of and they decay, it could cause problems with spacing for the permanent dentition, or pero disease could cause problems Because the enamel and dentin are thinner, there is a risk of endodontic complications. They could go through them and hit pulp chamber since it is large Early dental care should be stressed to keep dentition healthy and for assessing if orthodontics are needed. the earlier you get teeth to ortho the better. easier to correct Extraction purposes- never extract tooth if there is not a permanent tooth to replace it

Curve of Wilson

Cross-arch U curvature of the occlusal plane -how wide or narrow is arch

Primary Maxillary Central Incisor: Teeth E and F

Crown is wider mesiodistaly(side to side) than incisocervically (top to bottom) Only tooth of either dentition that is like this Labial view: mesial and distal edges look more rounded, slopes toward distal bc of attrition. They do NOT have mamelons. Labial surface is smooth Lingual: there are no pits present, prominent cingulum and marginal ridge, deep lingual fossa Proximal: Both surfaces are similar. Crown appears thick. CEJ curves toward incisal. Root: Single root, longer than crown

Primary mandibular first molar Teeth: L and S

Crown: Unlike any other in the dentition Prominent cervical ridge Height of Contour: Buccal- cervical 1/3, Lingual- middle 1/3 4 Cusps: Larger mesial cusps, mesiolingual cusp Transverse ridge: passes between mesiobuccal and messiolingual cusp Roots: Two roots positioned similarly to each other molars

Primary Maxillary Canine: Teeth C and H

Crown: longer and sharper cusp when it first erupts. Mesial/distal slopes are rounder: mesial cusp slope is longer than distal cusp slope Lingual ridge: extends from cingulum to cusp tip -divides lingual surface into 2 shallow fossa Incisal: diamond shape crown cusp tip off to distal Root: 2 times as long as crown and more slender than permanent canine

2 divisions of class II malocclusion

Division I: Maxillary anterior teeth protrude far over mandibular teeth (overjet) retrognathic profile Division 2: Maxillary laterals are flared out, centrals look straight up and down or even retruded. Prominent chin profile

myofunctional consideration- incompetent lips

Do not maintain seal

Primary maxillary first molar: Teeth B and I

Doesn't resemble any other tooth in dentition Very prominent cervical ridge Occlusal table: can have 4 cusps- mesiobuccal, mesiolingual, distobuccal, and distolingual. Mesial cusps are large and distal cusps are small. CAN have just 3 cusps, missing distolingual cusp Prominant transverse ridge H shaped groove pattern and 3 fossa Roots: Three root branches. Thinner with a lot of flare. Short root trunk. Lingual root is longest and most divergent

primary molars

Each quad has first and second molars (8 in all) Similar function, arch, and shape Replaced by permanent premolars Primary first molars do not resemble any other tooth Primary second molar crown resembles permanent first molar Occlusal table: More constricted buccolingully than permeant molars Roots: flared beyond outline of the crown so that it can create room for the permanent premolar crown can come in. Also has short root trunk

Do males or females shed teeth and get permanent teeth earlier?

Femlaes

Calcification begins...

In utero (before birth) 13-16 weeks

Primary Mandibular Central Incisor: Teeth O and p

Labial view: Crown resembles Mandibular lateral incisor. Very symmetrical. Appears much wider compared to permanent mandibular central incisor. Lingual: Smooth and tapered toward cingulum. Marginal ridges less pronounced than on primary max. incisor Proximal: CEJ curvature greater on mesial than distal. Wider labiolingually Incisal: Centered over center of the root. Divides labial and lingual into equal halves Root: One single long and slender

Primary Mandibular Second Molar Teeth: K and T

Larger than primary Mandibular First Molar Most closely resemble form of permanant mandibular first molar Has 5 cusps- 3 buccal equal in sides Oval occlusal shape

Primary maxillary second molar: Teeth A and J

Larger than primary maxillary first molar. Resembles Permanent maxillary first molar but smaller USUALLY HAS CUSP OF CARRABELLI

Primary vs permanent dentition

Primary: smaller overall have a whiter enamel- dentin makes up most of tooth which is a yellowish color. bigger teeth make dentin show more crown is shorter- smaller crowns compared to entire tooth crown more narrow at cej- more bulbous significant attrition very prominent cervical ridge roots more narrow and longer than crown roots reabsorb as they shed enamel and dentin are thinner pulp cavity and horns are very large

Primary Mandibular Lateral Incisor: Teeth Q and N

Similar crown to central but it is wider and longer. Developed cingulum and deeper fossa. Incisal edge slopes distally Incisal view: crown not as symmetrical. Cingulum offset to distal. Root: May have distal curve. Has long groove down it

Primary Maxillary Lateral Incisor: Teeth D and G

Smaller in all aspects than central Crown longer than it is wider Crown is similar to central but is a lot smaller Sharper apex

Primary Mandibular Canine Teeth: M and R

Smaller labiolingually (front to back) Distal cusp slope longer than mesial Lingual surface smoother than maxillary Straight incisal edge Root is shorter than maxillary but still 2x the crown

centric relation

The end point of the mandible when retruded swallow

Phase 5 of arch development

The final phase of development of the final dental arch form and consists of eruption of the third molars. jaw may not be big enough for third molars

primary dentition

The first set of 20 primary teeth (10 in each arch) Incisors, canines, molars (no premolars A-T -shed and replaced by permanent dentition

are interproximal spaces normal on primary teeth?

Yes, necessary for proper alignment, permanent teeth will be larger and need more space

Parafunctional habits

movements of the mandible that are not within the normal range of motion associated with mastication, speech, or respiratory movements often subconscious ex: clenching bruxism (grinding)- lead to attrition or abrfraction thumb/finger sucking Most used treatment for these is mouth guard or splint can help spread out occlusal forces and stop further damage

articulating eminence

on underside of temporal bone, in front of fossa. smooth rounded ridge that is ramp shaped.

Teeth erupt in...

pairs

What can occlusal trauma cause? can you stop it?

small changes in periodontium You can help it to not get worse but it may be irriversible

Curve of Spee

smile line curves up in occlusion

Angle's 3 classification of malocclusion

system used to classify and address malocculsion

TMJ

temporomandibular joint (mandible+ temporal bone)

mandibular rest position

when mandible is in rest state -average rest space is 2-3 mm between masticatory surfaces -usally when sleep -mandibular rest position larger than 2-3 mm larger and where tounge is placed - failure to assume position can cause parafunctional habit