Perio 9 - Occlusal Forces and the Periodontium (Dr. Gyurko)

- Attachment of tooth to bone

- Shock absorption

- Space for blood vessels and nerves

- Transmission of forces to bone

what are the four physical functions of PDL as it relates to occlusion?

- Adaptation and remodeling in response to occlusal forces

- Remodeling in response to orthodontic forces

what are 2 adaptive functions of PDL as it relates to occlusion?

70-150N

What is considered normal occlusal force load?

axial to the root (with limited lateral component)

What is considered normal occlusal load angle?

episodic (vs cleniching)

In terms of occlusal duration, normal chewing is...

continuous

In terms of occlusal duration, clenching is

True

T/F: There is no/minimal direct contact between antagonists during normal chewing

axial

uniform stress distribution of occlusal load is known as _____ load

Lateral

excessive stress distribution on mesial root tip is known as _____ load

300-500N

What is the excessive occlusal load force?

30 degrees

What is the excessive occlusal load angle?

5 million cycles (or continuous)

What is the excessive occlusal load duration?

- Tooth/restorations

- Tooth root

- Periodontium/alveolar bone

- Masticatory muscles

- TMJ

What structures may be damaged under excessive occlusal load? (5)

no

can occlusal trauma cause increased BOP?

no

can occlusal trauma cause increased probing depth?

no

can occlusal trauma cause attachment loss?

yes

can occlusal trauma cause a widened periodontal ligament space?

no

can occlusal trauma cause horizontal bone loss?

no

can occlusal trauma cause vertical bone loss?

no

can occlusal trauma cause tooth loss?

yes

can occlusal trauma cause tooth mobility?

PDL

Irving Glickman's (Tufts) concept of occlusal trauma says that occlusal trauma jiggles the tooth and 'pumps' the infection apically along the __________

Occlusal trauma + inflammation

Vertical bone loss is caused by what two things?

horizontal bone loss

inflammation without occlusal trauma causes what kind of bone loss?

trauma from occlusion

What is a co-destructive factor of bone loss?

Extent of inflammation

What determines the extent of bone loss?

horizontal bone loss

thin bone + inflammation = what type of bone loss?

vertical bone loss

thick bone + inflammation = what type of bone loss?

true (Waerhaug's concept)

t/f: occlusal trauma is not a contributing factor to vertical bone loss

vertical bone loss

Occlusal trauma with simultaneous active periodontitis can accelerate attachment loss and can result in _________. This is only seen with large occlusal forces in animal experiments

True

T/F: While occlusal trauma alone does not cause periodontal attachment loss or bone loss, it may accelerate existing periodontal disease

acute

Acute or Chronic Occlusal Trauma:

- This occlusal trauma occurs from injury such as from biting on an olive pit or getting a filling that is too high

acute

Acute or Chronic Occlusal Trauma:

- This occlusal trauma results in toothache, percussion sensitivity and tooth mobility.

chronic

Acute or Chronic Occlusal Trauma:

- This occlusal trauma occurs in response to bruxism, clenching, tooth wear, faulty restorations, and tooth drifting

chronic

Acute or Chronic Occlusal Trauma:

- This occlusal trauma is asymptomatic; only tooth mobility is detected clinically

primary occlusal trauma

Primary or Secondary Occlusal Trauma:

- This occlusal trauma results from excessive occlusal forces

secondary occlusal trauma

Primary or Secondary Occlusal Trauma:

- This occlusal trauma results from normal occlusal forces on a weakened (reduced) periodontium

D) Attachment loss (occlusal trauma shows no attachment loss!)

Occlusal trauma will cause all of the histologic findings EXCEPT one:

A) Resorption of collagen, bone, and cementum (red zones)

B) Widened PDL

C) Increased mobility

D) Attachment loss

D. All of the above

Occlusal trauma may be due to:

A. Accidentally biting on a hard object

B. Clenching while asleep

C. Chewing with just a few teeth left

D. All of the above

B. Increased mobility

Occlusal trauma can cause:

A. Attachment loss

B. Increased mobility

C. Vertical bone loss

D. Tooth loss

Stage I: injury

In which stage of tissue response to acute occlusal trauma does PDL inflammation (microscopic vascular changes) occur?

Stage I: injury

In which stage of tissue response to acute occlusal trauma does bone resorption (microscopic; not clinical) occur?

Stage I: injury

In which stage of tissue response to acute occlusal trauma does PDL widening occur?

Stage I: injury

In which stage of tissue response to acute occlusal trauma does increased tooth mobility occur?

Stage II: repair

In which stage of tissue response to acute occlusal trauma does PDL inflammation stop (no more inflammation)?

Stage II: repair

In which stage of tissue response to acute occlusal trauma does formation of new PDL, bone and cementum occur?

Stage III: Adaptation

In which stage of tissue response to acute occlusal trauma does widened PDL remain?

Stage III: Adaptation

In which stage of tissue response to acute occlusal trauma does tooth mobility remain?

Stage III: Adaptation

In which stage of tissue response to acute occlusal trauma demonstrates no pocketing, no attachment loss?

- Widened PDL remaining

- Tooth mobility remaining

In stage 3 of tissue response to acute occlusal trauma, what compensates for persistent occlusal trauma? (2)

secondary occlusal trauma

Normal occlusal forces on reduced periodontium may cause ____________ (the periodontium is not strong enough for a given occlusal force)

true

t/f: consequences of secondary occlusal trauma are the same as with primary trauma (widened PDL, increased mobility, no progression in attachment loss)

tooth mobility and migration

A common form of secondary occlusal trauma: normal occlusal forces acting on reduced periodontium result in _________ and _________

- Periodontitis

- Increased mobility

- New interproximal gaps

- Tooth extrusion

What are clinical signs of pathologic tooth migration?

severe advanced disease

Pathologic tooth migration is generally a sign of what?

secondary occlusal trauma

Is pathologic tooth migration a result of primary or secondary occlusal trauma?

pathologic tooth migration

Patient presents with the following:

- Periodontitis

- Increased mobility

- New interproximal gaps

- Tooth extrusion

What is the diagnosis?

B, D

Which of the following are caused by occlusal trauma?

A) Periodontal attachment loss

B) Increase tooth mobility

C) Bone loss

D) Cause widened PDL

A, C

Which of the following are NOT caused by occlusal trauma?

A) Periodontal attachment loss

B) Increase tooth mobility

C) Bone loss

D) Cause widened PDL

Periodontitis treatment

Which treatment is more important: treatment of periodontitis or occlusal trauma?

attachment loss

Periodontal inflammation + occlusal trauma will result in what?

true

t/f: occlusal adjustment may aid in attachment gain after primary attachment loss due to periodontitis

false, occlusal trauma itself does not cause attachment or bone loss!

t/f: occlusal forces cause attachment loss

100 microns (0.1 nm)

There is a physiological tooth mobility due to the orientation and elasticity of periodontal ligament fibers. Under normal forces this physiological mobility is up to ___ microns

incisor

(single rooted anterior tooth > multi-rooted molars)

which tooth would you expect to have more physiologic mobility? A molar or an incisor?

- Height of alveolar bone in relation to length of root

- Width of PDL

- Shape and number of roots

What 3 things determine tooth mobility?

More

More bone loss = more or less mobility?

Less

Narrow PDL = more or less mobility?

Less

More roots and thicker roots = more or less mobility?

Move the crown in a bucco-lingual direction with two instruments or with one instrument and a finger

How can we assess mobility clinically?

No mobility

a patient that has less than 0.1mm of tooth mobility has a what grade of mobility?

grade I

a patient that has 0.1mm-1mm of tooth mobility has a what grade of mobility?

grade II

a patient that has more than 1mm of tooth mobility has a what grade of mobility?

grade III

a patient that has vertical or twist mobility has a what grade of mobility?

- Occlusal trauma

- Periodontal abscess

- Periodontitis

- Root fracture

what are 4 causes of tooth mobility?

- Occlusal adjustment

- Distributing occlusal forces (molar support)

what is the treatment for occlusal trauma causing tooth mobility? (2)

Elimination of cause (SRP, root canal treatment)

what is the treatment for periodontal abscess causing tooth mobility?

- SRP

- Splinting for patient comfort

what is the treatment for periodontitis causing tooth mobility? (2)

- Extraction

- Implant placement

what is the treatment for root fracture causing tooth mobility? (2)

ALL ARE INDICATIONS

Which of the following are indications for splinting of teeth?

A) For patient comfort on mobile teeth

B) Pathologic tooth migration

C) Guided tissue regeneration on mobile teeth

D) Prosthetics where multiple abutments needed

control of periodontal ligament

What is a prerequisite to splinting of teeth?

No - splinting only mechanically stabilizes teeth, it does NOT by itself induce periodontal regeneration

Does splinting induces periodontal regeneration?

thinning

what happens to the PDL of a molar tooth that has no opposition?

all are consequences (USE IT or LOSE IT)

Which of the following is considered a consequence of having no antagonist (lack of occlusion)?

a. Thin PDL

b. Reduction in bone density

c. Supra-eruption of tooth

d. Apparent attachment loss

e. Furcation exposure

posterior bite collapse

what event has occurred due to the missing molar?

All of the above

Which of the following are periodontal/occlusal problems that can arise from misaligned teeth?

A) Super-eruption, resulting in root/furcation exposure

B) Molar tipping, psuedopocket

C) Open contact, a risk factor for food impaction and gingival inflammation

Non-carious cervical lesions (NCCL)

What event has occurred in this patient that brushes too hard but has no caries (clean hard dentin) and no sign of periodontitis?

- Abrasion

- Abfraction

What are the two chief mechanisms of causing Non-carious cervical lesions (NCCL)?

Non-carious cervical lesions

Increased frequency of ______ found in subjects with

- Improper brushing technique (horizontal scrubbing)

- Excessive manual force

- Hard bristle toothbrush

- Frequent brushing

abfraction

Define the following:

Loss of hard tissue in the cervical region of the tooth by non-axial forces exerted on the occlusal surface, which cause microfractures of dental tissues in areas of stress concentration

- Toothbrush abrasion and

- Chemical erosion due to acidic food and drinks

Toothbrush abrasion does not completely explain NCCLs as in laboratory experiments brushing eliminates only minimal amount of tooth material. Abfraction is not a satisfactory explanation either.

The current concept is that NCCL are likely caused by the combined effect of what two things?

resorption

Low PDL fiber strain leads to bone __________

formation

High PDL fiber strain leads to bone __________

true, no tooth movement without PDL!

t/f: tooth movement is only possible if PDL present

- Implants

- Ankylosed roots

what are two situations where teeth would be immobile?

creates bony defect (dehiscence)

what is the most likely consequence of moving tooth through cortical bone (buccally)?

bone/gingiva formation (good for implants)

what is the most likely consequence of extrusion of a tooth?

- Unlikely to create new attachment

- May create deeper pocket

what is the most likely consequence of intrusion of a tooth?

- Can eliminate mesial pocketing

- May expose furcation

what is the most likely consequence of molar uprighting?

inflammation

Orthodontic movement of teeth can be safely performed on an _______-free periodontium