Role of trauma from occlusion in periodontal diseases

Question 1

Describe the physiology of occlusion on the periodontium.

Answer 1

1. Periodontium attaches to tooth and alveolar bone (acts as shock observer)
2. This dissipates occlusal forces to surrounding tissues
3. If tissues can’t handle load, there will be changes (irreversible or reversible) seen in those tissues.

Question 2

Define occlusal trauma

Answer 2

• Injury resulting in tissue changes within the attachment apparatus.
• The apparatus includes PDL, alveolar bone and cementum.

Question 3

How can we diagnose occlusal trauma?

Answer 3

-It is defined and diagnosed by histological changes therefore can only get definitive diagnosis by sectioning tooth and surrounding tissue.

• As clinicians, we use clinical and radiographic tools to help us diagnose OT. There are occlusal trauma indicators to look out for (next card).

Question 4

What are the indicators of occlusal trauma?

Answer 4

1. Tooth mobility
   - May also be seen in pts with reduced periodontium and situations unrelated to occlusion (apical pathology, root fracture, acute perio abscess)

2.Radiographic signs
-Widening of perio ligament space
-Vertical infra bony defects (crescent shaped bone loss)
3. Drifting of teeth

4. Pain
   -Sensitive or TTP
5. Fremitus
   -Tooth moves as occluded teeth slide laterally or in protrusion
6. TMJ disfunction
   -Indicative of heavy bite
7. Hypertrophy of muscles of mastication
   -Especially masseter muscle
8. Wear facets
   -More marked than usual, look in areas of occlusal loading (however they may not have caused the periodontal disease)

SEEING ANY OF THESE DOESNT DEFFO MEAN THE PT HAS OT
-May see mobility and tooth migration but pts can have it as a sequelae of perio disease

Question 5

Radiographic signs of OT

Answer 5

-Widening of perio ligament space

-Vertical infra bony defects (crescent shaped bone loss)

Question 6

Two categories of occlusal trauma

Answer 6

Indirect and direct

Question 7

What is direct OT?

Answer 7

Trauma directly applied to perio tissues (usually in opposing dentition)\
- Can appear as wear facets or on opposing gingivae

Question 8

What is indirect OT?

Answer 8

Trauma indirectly applied to periodontal tissues
- Usually through teeth being hit in an awkward way so takes abnormal forces

Question 9

What is primary and secondary occlusal trauma according to the old classification?

Answer 9

Primary: Abnormal occlusal loading on healthy gingival tissues (healthy perio support)

Secondary: Normal or abnormal occlusal loading on teeth with reduced perio support

Question 10

Where is OT placed in the new classification?

Answer 10

In the “Other conditions affecting the periodontium” under the traumatic occlusal forces subsection.

Question 11

What is the Glickman concept?

Answer 11

Using autopsy material, Glickman hypothesised that the type of attachment loss was different in teeth based on them undergoing:
1. abnormal amounts of loading
2. normal amounts of loading

They were said to have different pathways of destruction - the occlusion changes the way damaged occurred in pts with perio disease

Question 12

Use Glickman’s concept to describe how infra bony defects occur?

Answer 12

(See diagram for this)
1. Zone of irritation is area that plaque accumulates
2. Zone of co-destruction is where damage occurred due to occlusal loading
3. Perio fibres attaching tooth to bone change orientation upon loading
4. Instead of projecting horizontally, they project downwards
5. This causes disease to extend downwards to form infra bony defects (more damage at one site than another)

Question 13

What does Glickman’s concept not take into account?

Answer 13

The form of interdental bone.

• EXAMPLE:

If a tooth has thin bone mesially, it will affect the bone on the distal side of the adjacent tooth

If a tooth has thick bone mesially, it will not affect the bone on the distal side of the adjacent tooth
The thick bone scenario, it will form a vertical defect will form

Question 14

What is Waerhaug’s concept?

Answer 14

• Also looked at autopsy material and the apical extension of subgingival plaque relative to inflammatory cell infiltrate and bone levels.

-Concluded that attachment loss was a entirely due to inflammatory factors

• This means the vertical defects were entirely due to plaque and not at all occlusion

Question 15

Issues with cadaver studies?

Answer 15

1. No way to accurately assess occlusion of pt before death
2. No way to establish cause and effect of defects
3. No knowledge of habits/parafunction of pt

Question 16

What movement occurs in removable appliances?

Answer 16

Tipping movement

• Force is applied to one side of tooth deliberately
  -Pushes on crown - no control beneath crown, leading to tilting effect on tooth

Question 17

What is bodily movement?

Answer 17

Occurs in fixed ortho-controlled movement on the root, pushing tooth physically vertically through the bone (see diagram on notes)

Question 18

Explain the NORMAL pressure zone formed from the tipping and bodily movements?

Answer 18

The pressure zone forms if forces applied do not occlude PDL blood flow:

1. Vascularisation increases
2. Vascular permeability increases
3. Vascular thrombosis occurs
4. Cells and collagen fibres become disorganised
5. Direct bone resorption occurs (dissolves to make space for moving tooth)

Question 19

Explain the EXCESSIVE pressure zone formed from the tipping and bodily movements?

Answer 19

Excessive forces can occlude PDL blood flow:

1. Necrosis of PDL occurs
2. Osteoclasts appears sub surface
3. Undermining or indirect resorption occurs (type of bone loss)

Question 20

What is a jiggling force?

Answer 20

Forces applied in 2 alternate directions (replicated tooth being battered in occlusion)

In studies they tried to generate jiggling forces to see the reaction of the normal peridontium.
The teeth were not allowed to move away from the force (like in ortho)
The pressure and tension on both sides were the same on ‘jiggled’ tooth

Question 21

What happens in jiggled teeth in a healthy periodontium with good bone support?

Answer 21

1. As jiggling forces are applied to the tooth, the PDL widens
2. When PDL widens, it becomes like a shock absorber to absorb the forces
3. Clinically, the teeth are more mobile
4. If these teeth were high in occlusion (causing the issue), adjusting the occlusion will resolve the PDL widening

Question 22

What happens in jiggled teeth in a healthy periodontium with reduced bone support? Assume the patient’s perio has been treated and they have responded to treatment, leaving them with a reduced level of perio ligament.

Answer 22

1. It will act the same way as the tooth with good bone support (widening will resolve)
2. However due to the reduced bone support, it may resist less force

Question 23

Jiggling (adaptive) forces in perio disease

Answer 23

Occlusal adjustment will restore PDL width and tooth mobility to normal

So when force is removed from tooth, the PDL/bone goes back to normal

Question 24

Excessive forces in perio disease

Answer 24

More force put on tooth, the attachment level decreased

Question 25

Conclusions from these jiggling experiments

Answer 25

In healthy periodontium (with or without reduced bone support) :

1. Bone resorption will occur in response to traumatic occlusal forces
2. PDL will widen
3. Resorption stops when force is compensated for
4. NO APICAL MIGRATION WILL OCCUR OF JUNCTION EPITHELIUM OR LOSS OF ATTACHMENT (POCKET DEPTHS)

In active periodontal disease:
1. Bone resorption occurs from jiggling forces
2. If tissues cannot adapt, apical migration of junctional epithelium and bone loss/attachment loss occurs
3. Periodontal disease is aggravated by occlusal trauma

there has been other studies that have claimed to debunked these concepts

Question 26

KEY POINTS

Answer 26

1. Perio tissues respond and adapt to occlusal loading even with reduced perio support following perio disease
2. Occlusal forces cannot initiate perio breakdown
3. Successful treatment of perio disease will arrest destruction even if occlusal trauma persists
4. Where forces are too great for adaptation, teeth may become mobile or drift
5. There may be some benefit to occlusal therapy but not strong evidence to support routine adjustment

Question 27

What is abfraction?

Answer 27

Wedge shaped cervical lesion resulting in flexure of tooth with excessive load as the cause

Now determined that no evidence to support the existence of abfraction

Question 28

How do we assess occlusion? (what are we looking for)

Answer 28

1. Occlusal interferences
2. Tooth loss
3. Wear facets
4. Assess occlusion on semi adjustable articulator
5. Rotations/tilts
6. Palpate TMJ and MOM

Question 29

What are the issues associated with splinting teeth?

Answer 29

Only consider if it won’t cause more harm than good

1. Acts to mask pocket depths
2. Plaque retentive factor
3. Affects prognosis of adjacent teeth
4. Hard to get floss through, needs AMAZING oral hygiene.