OCCLUSION CLASS - all cards here

Question 1

Define the following:
* Occlusion
* Centric occlusion
* Eccentric occlusion
* Centric Relation

Answer 1

Occlusion:
Any contact of opposing teeth.
Centric Occlusion:
The maximum intercuspation or contact of the teeth of the opposing arches. Also called
acquired centric and habitual occlusion.
Eccentric Occlusion:
Any relation of the mandibular to the maxillary teeth other than centric occlusion.
Centric Relation:
(1) The most retruded physiologic relation of the mandible to the maxilla from which
lateral movement can be made. Can exist at various degrees of jaw separation and
occurs around the hinge axis.
(2) The most posterior relation of the mandible to the maxilla at the established vertical
relation.

Question 2

Define the following:
* Abfraction
* Attrition
* Bruxism
* Buttressing bone

Answer 2

Abfraction:
Theoretical tooth surface abrasion in conjunction w/ occlusal forces
Attrition (dental):
Physiological wearing away of a substance or structure, such as the teeth
Bruxism:
Habit of grinding, clenching, or clamping the teeth; forces generated may
damage tooth and/or tooth supporting structures
Buttressing Bone
Marginal linear aspect of bone, may be formed in response to heavy occlusal
forces

Question 3

Define the following:
* Facet
* Fremitus
* Occlusal interference
* Occlusal prematurity

Answer 3

Facet
Flattened or worn spot on the tooth surface.
Fremitus
Palpable or visible movement of a tooth when subjected to occlusal forces.
Occlusal interference
Any contact that inhibits the remaining occluding surfaces from achieving
stable and harmonious contacts
Occlusal prematurity
Contact on opposing teeth occurring before the desirable inter-cuspation

Question 4

Define the following:
* Trauma from Occlusion (TFO)
* Occlusal traumatism
* Excessive occlusal forces
* Traumatic occlusal forces

Answer 4

Trauma from Occlusion (TFO)= Occlusal Trauma (OT)=diagnosis
Injury resulting in tissue changes within the attachment apparatus, including PDL,
supporting alveolar bone and cementum, as a result of occlusal forces (etiology).
Occlusal Traumatism (OT)
Functional loading of teeth, usually off-axis, that is of sufficient magnitude to induce
changes to the teeth (e.g., fractures, wear) or supporting structures. Changes may
be temporary or permanent.
Excessive occlusal forces (EOF)
Occlusal force that exceeds the reparative capacity of the periodontal attachment
apparatus, which results in occlusal trauma and/or causes excessive tooth wear
(loss).
Traumatic Occlusal Force (TOF):
Any occlusal force resulting in injury to the teeth and/or periodontal attachment
apparatus.

Question 5

What happens on the tension & compression sides during TFO?

Answer 5

COMPRESSION SIDE
PDL space is reduced as fibers are
compressed
Loss of fiber orientation
Increased capillary permeability, rupture of
blood vessels and hemorrhage into PDL
perivascular spaces (edema)
Resorption of alveolar bone proper (root
resorption if severe) then widening of PDL
space.

TENSION SIDE
Increase in PDL space
Rupture of PDL fiber bundles
Compression of PDL blood vessels and
hemorrhage into perivascular spaces
Deposition of new alveolar bone and
decrease in PDL space (If severe,
cemental tears)

Question 6

What are the 2017 World Workshop statements regarding TFO?

Answer 6

Fan et al 2018
1. TOF and excessive occlusal forces DO NOT initiate periodontitis or connective tissue attachment loss.
2. For existing periodontitis, there is weak evidence that TOF may increase rate of connective tissue attachment loss.
3. There is still need to evaluate/address occlusion in periodontitis patients.

“Overall, past studies showed lack of cause & effect”

Question 7

What is the earliest literature on TFO?

Answer 7

Trauma is the 1ry Etiology of Perio. Adjust to prevent perio. = Karolyi 1901, Stillman 1926, Bunting 1936, McCall 1939.

Trauma has NO effect on perio. = Gottlieb & Orban 1931, Orban & Weinmann 1933.

Trauma may lead to increased PD. Adjust in perio patients = Box 1935, Stones, 1938.

Question 8

What studies examined the pathways of inflammation in periodontitis (without trauma)?

Answer 8

Weinman 1941 - studied Perio
Histologic analysis of 32 human jaws available from autopsy. Investigated pathways of inflammation for periodontitis.

Findings:
Interproximal: Follows the course of
the interseptal artery. Supporting
alveolar bone is destroyed first, then
alveolar bone proper.
Buccal and Lingual: Follows
course of blood vessels on
PERIOSTEAL side of bone then
penetrates into bone.
Inflammation only rarely
penetrates into the PDL.

Question 9

What studies examined the pathways of inflammation in periodontitis, with trauma?

Answer 9

Macapanpan & Weinman 1954 - studied Perio + Trauma
35 Sprague-Dawley rats.
1 mm piece of rubber dam inserted between upper right 1st and 2nd molars.
Rubber dam caused both trauma and gingival
inflammation.
Histology: 4 rats at 1, 3, 6, 12, 24, 36, 48, 60 and 72
hours.
Findings
* Trauma damaged PDL on pressure and tension
sides.
TENSION SIDE: Inflammation spread directly into
PDL.
Trauma alone did not appear to cause periodontitis.

Comar, Kollar & Gargiulo ‘69 - studied perio + trauma
4 Rheuses monkeys.
Findings
* Heavy osteoclastic resorption at the alveolar
crest and in furcations.
* Bone formation around endosteal surfaces.
* Greatest changes in 1st 14 days.
* Increased “pseudo” PD
NO altered pathway of inflammation.
NO apical migration of JE or infrabony
pocket.

Ewen and Stahl, 1962 - studied perio + trauma
8 Mongrel dogs.
Findings
* Gingival inflammation spread into:
* Alveolar bone.
* PDL on TENSION side.
* Infrabony pocket noted on ONE
specimen at 12 months.

Stahl, 1968 - studied perio + trauma
4 human jaws.
Findings
* Inflammation most often directly into
the crestal septum
* Infrabony pocket in only one case
* Inflammatory and destructive patterns
resulting from occlusal trauma +
inflammation have LIMITED
PREDICTABILITY

Question 10

What studies examined the pathways of inflammation, in trauma only situations?

Answer 10

Wentz, Jarabak & Orban ‘58 - studied trauma
6 Rheuses monkeys.
Findings:
Hemorrhage, disorganization and necrosis
of the PDL + Widened PDL
Bone resorption at crest, furcation and apex; Undermining resorption.
Bone formation on buccal and endosteal surfaces.
Cemental and dentinal resorption.
Early traumatic changes gone by 3 months due to widened PDL and adaptation
* NO EVIDENCE of gingivitis or periodontitis at 3 or 6 months
= trauma doesn’t cause periodontitis or inflammation

Question 11

Summarize the effects of Perio, Perio + Trauma, and Trauma only on the pathways of inflammation.

Answer 11

Pathways of Inflammation with Perio only: IP-Interseptal artery; B/L-Periosteal vessel
into bone. Attachment loss.

Pathways of Inflammation with Trauma only: Widened PDL, bone resorption at crest,
furcation and apex; Undermining resorption, bone formation on buccal and endosteal
surfaces. No attachment loss. * Adaptation/regeneration: Occurred by 3 months

Pathways of Inflammation with Perio + Trauma:
Comar, Kollar and Gargiulo —> NO altered pathway of inflammation.
Macapanpan and Weinman; Ewen & Stahl; Stahl—> Inflammation spread directly
into PDL on the TENSION side. AL in few but not all cases.

Question 12

How much, exactly, is an Excessive Occlusal Force?

Answer 12

Mühlemann 1954 A-E (Monkeys)
Mühlemann 1960
Mühlemann, Savdir and Rateitschak, 1965
Initial TM
* 0 - 100 grams; T100
* Intra-alveolar displacement
* Histomorphologic structure of PDL, not width
Secondary TM
* > 100 grams; T500
* Elastic deformation of alveolar bone

Frequency of jiggling
No Trauma: 4 to 5 day or
2 day jiggling
Trauma: 4X daily jiggling
Adaptation: 3 - 4 months

Mühlemann and Herzog, 1961
(Case report)
4 - 5 or 2 day alternating for 1 mo, no increase
in mobility which means no trauma
4X daily alternating for 4-6 wks, large increase
in mobility which means acute trauma
After 3-4 mo mobility decreased to control
levels which means adaptation
Cusps augmented, mobility increased which
means new acute trauma.

Question 13

What are the 4 components of occlusal force / occlusal trauma?

Answer 13

• Magnitude
• Direction
• Duration
• Frequency

Question 14

Does splinting decrease mobility?

Answer 14

Wüst, 1960
Group A (13 patients) received removable
splints in the upper jaw. Group B (8
patients) was not splinted.
Mobility decreased ≈ 11% in non- splinted
cases, whereas it increased in splinted
cases.
Only 20 months later was there a definite
decrease in mobility both in group A and B.
No sig. differences between both groups. = Splinting does not decrease mobility.

Renggli and Schweizer, 1974
Hypothesis:
Splinting decreases mobility
Findings:
NO SIGNIFICANT CHANGE in
mean tooth mobility of test or
control teeth

Galler & Selipsky ‘79
Effects of splinting after osseous surgery
Bilateral similar disease
*
One side splinted and other not then evaluated at 3, 16, and 24 weeks.
*
Results: Initial increase in mobility postop decreasedto preop levels after 6 mosin splinted and unsplinted.
*
Conclusions:Splint for patient comfort, replacement of missing teeth, post ortho retention, or increasing (progressive) mobility due to secondary trauma, but not to reduce increased temporary mobility in the postop healing phase after osseous surgery.

Scandinavian Studies Supporting Increased Mobility in Splinted Cases. Nyman, Lindhe, et. al: J.C.P. 2:53,1975 and 9:409, 1982
*
20 pts. with advanced disease age 27-69.
*
Stability of cases achieved with pocket elimination and balanced occlusion using multiple cantilevers.
*
In only 8% of fixed restorations did total PDL area of abutments equal or exceed that of the replaced teeth –refutes Ante’s law.
*
In 5% of the bridgesthe PDL area of the abutments was < 50% of the PDL area of the pontics.
*
Despite increased mobility and advanced bone loss all bridges functioned well for the 8-11 years (end of observation period) without further attachment loss.
*
Conclusion:Permanent stability of fixed bridges can be obtained with minimal periodontal support even with marked hypermobility of abutments.

Question 15

Describe the Waerhaug study on the advancing plaque front

Answer 15

Waerhaug 1979a, b
Human autopsy (used 31 sets of human teeth)
Examined the postmortem tooth mobility , study models, radiographs, angular defects, occlusal interferences.

Attachment Loss: 0.2 to 1.8
mm between apical border of
plaque and periodontal fibers.
Shape of septum related to
plaque downgrowth: If the
same on 2 teeth then bone
loss was horizontal; if unequal
then bone loss was angular.

Infrabony pockets: ALWAYS
associated with the downgrowth
of subgingival plaque
Trauma NOT a co-factor:
Angular defects equally adjacent
to traumatized and nontraumatized
teeth

Question 16

Describe the Glickman studies on trauma, splinting, and furcations.

Answer 16

Pathways of Inflammation (1962)
* Without Trauma:
IP: Follows artery into septum
B/L: Periosteal vessels, penetrates bone
* With Trauma:
Directly into PDL on PRESSURE side

Trauma from Occlusion (TFO) (1963)
* Tissue injury (Diagnosis).
Traumatic Occlusion
* Occlusion that causes the injury; arrangement of teeth. Not the injury itself
but the condition that produces the injury

Zone of Irritation: NO compression
* Fibers from tooth to soft tissue
* Coronal to transseptal & alveolar crest
fibers
* Affected by marginal inflammation
* Not affected by occlusal trauma
Zone of co-destruction: Compression
* Fibers between 2 hard tissues (tooth, bone)
* Affected by trauma & perio inflammation
* Area where trauma & inflammation BOTH
act
Perio + TFO = Accelerated progression of
periodontitis

Effect of occlusion on Peridontium after flap surgery (1966)
* Hyperfunction: Widened PDL, short fibers, increased in number, perpendicular
* Hypofunction: Narrowed PDL, fibers long, reduced in number, sometimes parallel

Question 17

Describe how Glickman diagnosed TFO. Then, describe the current consensus description for TFO (by Fan 2018)

Answer 17

Diagnosis of TFO (Glickman 1965)
* Widened PDL
* Thickened lamina dura
* Vertical, angular or crater-like resorption
* Radiolucence or condensation of alveolar bone
* Root resorption
* Mobility greater than that due to bone loss
* Simple Periodontitis: Periodontitis alone
* Compound Periodontitis: Periodontitis + trauma from occlusion

Fan 2018
1. Fremitus
2. Mobility
3. Occlusal discrepancies
4. Wear facets
5. Tooth migration
6. Fractured tooth
7. Thermal sensitivity
8. Discomfort/pain on chewing
9. Widened PDL
10. Root resorption
11. Cemental tear

Question 18

Describe the Glickman findings regarding the pattern of bone loss.

Answer 18

Pattern of bone loss (Glickman 1965, 1967)
* Trauma from occlusion affects pattern
and severity of bone loss
* Angular defects and infrabony pockets
NOT PATHOGNOMONIC of trauma
from occlusion but it is highly likely.
Angular defects on the radiograph are
suggestive of TFO. No other local factor
has been consistently identified.
* Trauma from occlusion alone does not
cause any type of pocket.

Question 19

Describe the Polson studies on ligature-induced periodontitis and added trauma

Answer 19

Polson, 1974b
Periodontitis induced with ligatures, then trauma was added (toothpicks wedged interproximally)

Immediate: Necrosis of PDL from crest to midroot
* 3 Wks: Highly cellular, loosely arranged PDL. Widened
coronally.
* 8 Wks: New bone formation. PDL width similar to control side.
No ankylosis with mechanical trauma
(Stimudent). in contrast to thermal trauma (1974a).
CEJ to JE
* NO DIFFERENCES between test and
control sides
* CEJ to AC
* NO DIFFERENCES between test and
control sides
* NO CO-DESTRUCTIVE EFFECT OBSERVED

Meitner ‘75
10 Squirrel monkeys
ControL: no treatment
Test: Jiggling trauma (Alastik) alternated every 48 hours

Loss of Connective Tissue Attachment
* NO DIFFERENCE between perio alone
& perio plus jiggling in 3 of 4 groups of
surfaces.
* Loss of Crestal Bone Height
SIGNIFICANTLY GREATER LOSS in perio
plus jiggling group.
* Loss of Percentage Osseous Tissue
SIGNIFICANTLY GREATER in perio plus
jiggling group

Polson, Meitner, Zander, 1976b
8 Squirrel Monkeys
ControL: No periodontitis
Test: Ligature Periodontitis
Loss of Connective Tissue Attachment
* NOT produced by jiggling trauma
* Loss attributable to periodontitis alone
* Loss of Percentage Osseous Tissue
Significant regeneration AFTER jiggling
was stopped
NO regeneration when periodontitis was present
* Loss of Crestal Bone Height: 40% regenerated
AFTER jiggling was stopped
NO regeneration on perio side AFTER jiggling
stopped
Conclusion: Marginal inflammation inhibits the potential for bone regeneration.
In perio + TFO, relieving TFO does not induce
regeneration, but controlling perio does.

Polson, Adams, Zander 1983
4 Squirrel monkeys
Control: Ligature periodontitis for 5 wks, then Jiggling + ligature perio for 10 wks
Test: Ligature periodontitis for 5 wks, then Jiggling + ligature perio for 10 wks
Test 2: Jiggling (no perio) for 10 wks

Loss of Connective Tissue Attachment
* No significant difference between the test
and control sides
* Loss of Crestal Height
* No significant difference between the test
and control sides
* Loss of Percentage Osseous Tissue
* Significant increase in bone volume on the test side
Conclusions
Regeneration of bone volume occurred in
the presence of hypermobility
No loss of connective tissue attachment in presence of hypermobility AFTER inflammation was resolved.
Management of periodontitis MUST be based on resolution of inflammation

Polson, Zander ‘83
10 Squirrel monkeys
Control: Ligature perio 20 wks
Test: Ligature perio 10 wks and jiggling + Lig perio for 10 wks

Loss of Connective Tissue Attachment
* NO DIFFERENCE between test and control
groups
* Loss of Crestal Height
* Significantly GREATER LOSS of crestal
height in TEST group
* Loss of Percentage Osseous Tissue
* Significantly GREATER LOSS of bone volume in
TEST group
Conclusion
Trauma from occlusion superimposed on
existing infrabony pockets:
INCREASED LOSS of crestal height;
INCREASED LOSS of bone volume;
DID NOT AFFECT loss of connective tissue
attachment.

Question 20

Describe the Lindhe studies

Answer 20

Svanberg & Lindhe ‘73
13 beagle dogs
No gingivitis; brushed 3x per week
Control: No trauma
Test: Jiggling trauma

Tooth Mobility
* ALL test teeth showed sig increase in
mobility. No change after 2 mo
* Radiology
* CONE SHAPED WIDENING of PDL on
pressure side
* Periodontal Ligament Area
* Markedly increased on pressure side after 30
days. Both pressure & tension sides increased at
180 days

Svanberg, 1974
18 Beagle dogs
Control: No trauma
Test: Jiggling trauma
13 dogs had regular toothbrushing & healthy gums; 5 dogs had accumulated plaque and gingivitis.

Two Phases of Tooth Mobility * Traumatic Phase
* Developing hypermobility, increasing vascularity,
vascular dilation, bone resorption
* Post-traumatic
* Permanently increased hypermobility, normal
vascularity, no osteoclasts
* NO APICAL MIGRATION of junctional epithelium
* Trauma DID NOT induce inflammation
* Trauma DID NOT influence established
inflammation

Lindhe, Svanberg ‘74
6 Beagle dogs
Surgical infrabony defects induced periodontitis
ControL: No trauma
Test: Jiggling trauma

Mobility: Increased for all teeth
* Radiology:
* Horizontal bone loss on test & control teeth
* Angular bone loss and cone shaped
widening of PDL on test teeth
* Attachment loss: Sig greater on test side
* PLA: Significantly greater on test side
* Accelerated progression of perio with trauma
* Agreed with Glickman’s hypothesis

Lindhe, Ericsson 1977
15 Beagle dogs; induced periodontitis and perio surgery. Compared trauma vs. no trauma
Control: No trauma 180 days; reduced periodontium; healthy periodontium
Test: Jiggling trauma 180 days; reduced periodontium; healthy periodontium

Conclusions
* Trauma from jiggling forces did not
initiate marginal destruction in a
reduced but non-inflamed
periodontium.
* No apical migration of JE due to
trauma from occlusion.

Ericsson, Lindhe, 1982a
8 Beagle dogs; induced periodontitis
Control: No trauma; active periodontitis
Test: Jiggling trauma; active periodontitis

Infrabony Pockets
* Found on 6 of 8 teeth
* Attachment loss 63% on test teeth and 45% on control teeth
* 2 dogs had horizontal bone loss and similar attachment loss on
test and control sides
* Infrabony pockets may be a prerequisite for accelerated
attachment loss
Conclusions:
** JIGGLING TRAUMA, under certain conditions, acts as a codestructive factor and can produce accelerated loss of
attachment.
Active periodontitis accelerated progression of perio with trauma
Infrabony defects caused by disease process
Supported Glickman’s hypothesis**

Question 21

What did Karring and Nyman find regarding tooth movement (tipping facially)?

Answer 21

Karring, Nyman ‘82
6 beagle dogs; toothbrushing & CHX daily
Control: No tooth movement
Test: Move tooth thru facial plate, then reposition. Or, move tooth thru facial plate, then retain at that spot

Findings:
Dehiscences will form when teeth
are tipped facially
Bone will reform in these defects
when teeth are repositioned
Tooth movements will not
necessarily be accompanied by a loss
of connective tissue attachment

Question 22

Compare and contrast the Lindhe vs. Polson study design. (Regarding magnitude, direction, duration, and frequency)

Answer 22

Lindhe:
Magnitude: Heavy
Direction: Mesio-distal
Duration: Short (closure)
Frequency: High (closure)

Polson
Magnitude: Light
Direction: Mesio-distal
Duration: Long (2 day)
Frequency: Low (2 day)

Question 23

Summarize what the early studies found regarding Occlusal Trauma. (early 1900’s to 1996)

Answer 23

Most studies (early 1900’s to 1996)
Did not show pocket formation in response to OT
Showed adaptive capacity of periodontium in response to
OT.
In absence of inflammation, “bony changes
accompanying occlusal trauma may be reserved by
discontinuing the offending occlusal forces.”
If periodontal inflammation was introduced and occlusal
trauma superimposed, apical migration of JE was similar
to areas where no occlusal trauma existed.

Consensus from 1999 Workshop
Occlusal trauma does not initiate plaque induced
gingivitis or periodontitis.
Subjects with occlusal discrepancies do exhibit worse
periodontitis.
Adjusting discrepancy did not improve mobility.
Mobility may have adverse effects on the
periodontium and its response to therapy ‘but is not
necessarily synonymous with occlusal trauma’

They also added this:
VIII. Developmental or Acquired
Deformities and Conditions
Occlusal Trauma
1. Primary
2. Secondary
Removed ‘Combined’ (Excessive force on
reduced periodontium) in 1999 classification

Question 24

What is the current (2018) consensus regarding Trauma from Occlusion?
1. Does occlusal trauma (OT) initiate
periodontal disease?
2. Does occlusal trauma lead to progression
of existing periodontal disease?

Answer 24

Minor trauma (from occlusion)
Increased capillary permeability, dilation
Edema, disturbed fluid exchange
Vascular damage with stasis, clotting, thrombosis
Lowered periodontal resistance?
Accompanying tissue effects, usually minor

Severe trauma (from occlusion)
Well-defined necrosis, including PDL,
cementum, bone.
Degenerative changes (hyaline, mucoid,
liquefaction)
Repair from PDL, endosteal cells, bone marrow,
Haversian systems (rear resorption)

Conclusions from 2017 World Workshop
* There is insufficient evidence evaluating impact of eliminating signs of Traumatic Occlusal Forces on the response to periodontal treatment.
* One RCT shows that there are improvements in
* periodontal outcomes as a result of reducing tooth mobility.
* OT and excessive occlusal forces do not initiate periodontitis or connective tissue attachment loss.
* For existing periodontitis, there is weak evidence that OT may increase rate of connective tissue attachment loss.
Therefore, still need to evaluate/address occlusion

Also:
NO EVIDENCE that OT causes periodontal attachment loss in humans or initiates periodontal disease.
LIMITED EVIDENCE (animal and human) that it causes
inflammation in the periodontal ligament.
WEAK EVIDENCE that TOF may be associated with severity of periodontitis.
May increase alveolar bone loss?
Animal-Yes
Human- No evidence

Recommendations from Workshop:
If see signs and symptoms of occlusal trauma and
patient’s comfort and function are impacted then
perform occlusal adjustment in conjunction with
periodontal therapy
Evaluate and record occlusion before, during and
after treatment
Treatment of occlusal trauma ‘may slow the
progression of periodontitis and improve the
prognosis’

Question 25

Define Primary Occlusal Trauma and Secondary Occlusal Trauma. What is a reduced periodontium?

Answer 25

Primary Occlusal Trauma:
Traumatic occlusal forces applied to a
tooth or teeth with normal periodontal
support. With Primary occlusal trauma,
clinically may see adaptive mobility
(does not progress)
Example is ‘high’ restoration with
mobility resolving following reduction.

Secondary Occlusal Trauma:
Injury resulting in tissue changes from
normal or traumatic occlusal forces applied
to a tooth/teeth with reduced periodontal
support.
May be seen as progressive mobility &/or pain
Prior to 1999 classification, if excessive
force and reduced support, old terminology
(1928) was Combined Occlusal Trauma.

Reduced Periodontium = Reinhardt 1984
in-vitro study, reduced is >60% of bone
support lost.

Question 26

Describe how orthodontic forces affect the periodontium.

Answer 26

Animal studies: Certain orthodontic forces can
adversely affect the periodontium and cause root
resorption, pulpal disorders, gingival recession and
alveolar bone loss.

• Observational studies: teeth with a reduced but
  healthy periodontium (no inflammation) may undergo
  successful tooth movement without compromising
  periodontal support (Martin et al. 2022;
  Zoizner et al. 2018).

Question 27

What are the signs & symptoms of bruxism?

Answer 27

Ramfjord ‘61
Signs & symptoms of bruxism:
* Increased mobility
* Pulpal sensitivity / bite tenderness
* Non-masticatory/excessive occlusal wear
* Dull percussion sound
* Muscle tenderness / spasm / hypertrophy /
* tiredness (am)
* Non-masticatory / excessive occlusal wear
* TMJ pain / Jawlock
* Audible sounds

Question 28

What is the Miller Mobility index?

Answer 28

Miller ‘50
1 = First distinguishable sign of movement > than
normal (physiologic)
2 = Movement which allows crown to move 1
mm from its normal position in any direction
3 = Tooth may be rotated or depressed in alveoli

Question 29

How does mobility affect regenerative procedures? How about periodontal treatment in general?

Answer 29

Cortellini & Tonetti ‘01
The simplified papilla preservation flap in
regenerative treatment of deep intrabony defects.
Clinical outcomes and postoperative mobility.
“Baseline mobility has a negative impact on
attachment gain following regeneration.”

Bernhardt ‘06
The influence of dynamic occlusal interferences on
probing depths and attachment level. Bernhardt O et
al. J. Perio 2006
‘The effect of non-working contacts on periodontal
disease status was discernible but weak in terms of
magnitude and specificity.’
(Note: This was a General population study, so many did not have periodontitis)’

Question 30

How does occlusion affect tooth loss in maintenance patients?

Answer 30

Martinez-Canut ‘15
“The main patient-related factors associated with TLPD were severe periodontitis and aggressive peridontitis, followed by heavy smoking, bruxism and fewer baseline teeth.”
“The main tooth-related factor was mobility, increasing the risk between 2-4 times more than the remaining tooth-related factors.”

Wang, Burgett & Ramfjord ‘94
UMich; 24 pts, 164 molar teeth
Furcation invasion (FI), mobility (M) & (FI + M) increased chance of AL and tooth loss over 8 years
Since AL at baseline was greater for M + FI teeth, benefit
of addressing M early (in advance) speculative
“Tooth mobility negatively affected outcome of periodontal
therapy and maintenance (more attachment loss)”

Question 31

What are the indications (and contraindications) for occlusal adjustment?

Answer 31

Indications for Occlusal Adjustment
AAP World Workshop, 1989, 2017
* Traumatic injuries / soft tissue injury
* food impaction
* Increasing mobility or fremitus
* Parafunctional habits
* In conjunction with orthodontic / orthognathic therapy

Contraindications for Occlusal Adjustment
AAP World Workshop, 1989
* Absence of a pre-treatment diagnosis
* As prophylactic therapy or only treatment for periodontal disease
* As primary therapy of bruxism
* Severe extrusion or malpositioned teeth
* When periodontal inflammation has not been controlled

Other contraindications:
Discrepancies in occlusal landmarks of more than one half cusp.
CR to MI discrepancies of more than one half cusp.
Advanced occlusal and incisal wear.
Poor tooth position
Severe skeletal discrepancies
Inability to establish an adequate anterior guidance.

Question 32

How does periodontal treatment affect tooth mobility?

Answer 32

Kerry ‘82
UMich; 93 pts moderate-advanced periodontitis; Modified Widman Flap (MWF), pocket elimination (PE), or curettage (C) Significantly decreased tooth mobility (TM) after initial non surgical treatment (with occlusal adjustment).
No significant change with subsequent Modified Widman Flap or Curettage.
Increased tooth mobility with pocket elimination.
Gradual slight decrease in tooth mobility over 2 year PMT for all treatments.

Fleszar, Knowles ‘80
1,974 teeth (72 pts)-8 yrs following MWF, flap surgery & subgingival curettage. Change in AL after surgery was related to initial TM, regardless of severity of
disease.
The greater the TM, the less effective the treatment response based on AL
* Teeth with an initial mobility of 2 did not gain attachment.
* Teeth with an initial mobility of 3 lost attachment.
* Only sites with mobility of 0 or 1 gained attachment.
However, we can postulate that mobile teeth can be successfully managed and maintained.

Burgett ‘92
50 patients; had either SRP or Mod Widman.
ControL: No occlusal adjustment.
Test: Occlusal adjustment.

Greater gain of clinical attachment for
adjusted patients (0.02 mm vs. 0.42 mm)
* Occlusal adjustment had no influence on
probing depth changes
* Response to occlusal adjustment was
similar for surgical and non-surgical
treatment
* Initial tooth mobility had no influence on
the response to occlusal adjustment
* No significant differences in reduction of
mobility between the adjusted and not
adjusted group

Nunn & Harrel ‘01
Examined the Effect of Occlusal Discrepancies on Periodontitis.
I-Relationship of Initial Discrepancies to Initial Clinical
Parameters.
Private practice patients, initial complete exam and occlusal
analysis then rerecorded at least 1 year apart
30 patients had none of the recommended
18 had non surgical therapy (partially treated)
41 had all recommended therapy.
Results:
Teeth with initial occlusal discrepancies had
significantly:
* Deeper probing depths (1mm)
* Worse prognoses
* Worse mobility
Some evidence that occlusal discrepancy is an
independent risk factor contributing to periodontal
disease

Nunn & Harrel ‘01
The Effect of Occlusal Discrepancies on Periodontitis.
II. Relationship of Occlusal Treatment to the Progression
of Periodontal Disease.
26 of 59 treated patients received occlusal therapy
30 patients had no occlusal therapy
Results:
Teeth with no discrepancies or treated initial discrepancies were only 60% as likely to worsen in prognosis over time compared to untreated teeth

Harrel & Nunn ‘09
Balancing contact (± working contacts)
and centric prematurities were
associated with less than good
prognosis

Question 33

Does Bruxism cause periodontal damage?

Answer 33

Manfredini ‘14
Systematic Review
* SUGGESTS: Bruxism cannot cause
periodontal damage per se.
* CRITIQUE: 6 studies, only 2 in perio population.
Different outcomes from PD to tooth migration, to
tooth loss.

Question 34

Does TFO cause abfractions? How about recessions?

Answer 34

NO EVIDENCE that TOF causes non-carious
cervical lesions (NCCLs).
Most studies used finite element analysis (not
clinical).
NCCLs may result from abrasion, erosion or
corrosion.

There is EVIDENCE from observational studies that
Traumatic Occlusal Force does NOT cause
gingival recession.

Question 35

What are the different types of bite splint / nightguard? What is a Michigan Bite Splint?

Answer 35

• Over-the-counter
• Aqualizer
• Anterior deprogrammer
• Michigan Bite Splint

The Michigan Splint is basically a Maxillary splint constructed with stops for all opposing teeth and control of contact relations in various excursions.
It has:
* Cuspid rise
* No incisal guidance beyond cuspid rise
* Freedom in centric on a flat plane: 0.5-1 mm on a flat surface.
* Centric occlusion contacts established in front of centric relation in the midsagittal plane
* Additional freedom of about 1 mm from centric occlusion to the cuspid rise in all lateral and protrusive excursions
* Allows the condyles to seek optimal position.

The splints should be as thin as practical (approximately 1-2 mm in the molar regions), made from heat-cured hard acrylic and polished.
Cuspid rise should be gradual, starting approximately 1 mm from centric occlusion and only steep enough to disocclude the balancing side. Soft liner on the occlusal surface is not recommended.

Question 36

What are the indications for the Michigan splint?

Answer 36

• Patients with TMJ and/or muscle disorders and pain.
• Severe bruxism.
• Diagnosis and treatment of trauma from occlusion to any part of the masticatory system.
• Establishment of optimal condylar positions in centric relation prior to definitive occlusal therapy.
• Stabilization of mobile maxillary teeth and to prevent eruption of mandibular teeth,
• Holding maxillary teeth in the desired position following orthodontic therapy or loss of opposing teeth.
• Temporary disocclusion of teeth for orthodontic or other purposes,
• Differential diagnosis for patients with signs and symptoms imitating TMJ or muscle disorders, but without origin in the masticatory system,
• Treatment of patients with tension headaches

Question 37

Describe the traditional, “old school” methods of creating a Michigan bite splint.

Answer 37

• Alginate impressions = pour plaster casts.
• Survey the teeth on the plaster cast to determine the retention areas
• Block out undercuts
• Raise vertical dimension to 2-3 mm between posterior teeth using a leaf gauge or folded paper
• Do a wax-up of the splint on the casts
• Confirm occlusion and canine guidance
• Flask the wax and obtain the plastic bite guard
• Remount the new plastic guard
• Check clinically - protrusion, laterotrusion

Similar processes can be used to create a lower bite splint.

Question 38

what are the basic movements of the mandible?

Answer 38

Hinge movement - small open-close movement. Condyles rotate, but do not move from the physiologic position.
Protrusion: Mandible moves forward
Lateral excursion: Mandible moves side-to-side. Usually, this means one condyle is rotating, and the other condyle is moving anteriorly and to the opposing side.
Immediate lateral shift: The condyle on the working side will shift laterally and slightly posteriorly.

Question 39

What are the types of occlusion?

Answer 39

Mutually protected occlusion: “Canine-protected occlusion”. Canine disoccludes all other teeth in lateral excursion.
Group function occlusion: “Unilateral balanced occlusion” - on the working side, the canine and posterior teeth guide the disocclusion of the nonworking side. this is more common in the aged population.
Bilateral balanced occlusion - only used in complete dentures. Both the working and nonworking side have even contacts. And, the anterior and posterior teeth contact in protrusion. (Basically it is a “flat plane” occlusion)
Centric occlusion: Both condyles are at the physiologic position, which is the most superoanterior position. Posterior teeth have solid & even contact, and the anterior teeth are in even but light contact - or slightly out of contact

Question 40

What is considered “normal occlusion”? What is an occlusal interference?

Answer 40

1. Canine guidance or group function guidance
2. Centric contact - even distribution
3. Anterior guidance

Occlusal interference: Undesirable occlusal contacts, or any contacts that should not be presented in normal occlusion

Question 41

What is the normal position of the condyles in centric relation?

Answer 41

CENTRIC RELATION
* Only rely on condyle position
* Both condyles in TMJ fossa
* At a superoanterior position
* Against articular disc and articular
prominence

Question 42

What are the indications for occlusal adjustment?

Answer 42

• Primary Occlusal Trauma
• Progressing Tooth Wear
• Tooth Migration
• Restorative Management
• Temporomandibular Dysfunction (TMD)
• Esthetics

Question 43

What are the methods of occlusal correction?

Answer 43

Selective Grinding
Restorative Dentistry/Occlusal Reconstruction
Orthodontics
Orthognathic Surgery
Extraction
Combinations of the above

Question 44

Define the following:
Centric relation, maximum intercuspation, centric occlusion, axial loading, occlusal landmarks, centric cusps, guiding inclines, supporting inclines

Answer 44

Centric Relation (CR) –TMJ position (the most anterior superior position of the condyle disc assembly within the glenoid fossa –Dawson)
*
Maximum Intercuspation (MI) –Tooth to tooth position
*
Centric Occlusion (CO) –MI and CR coincident
*
Axial Loading–Force directed along long axis of tooth
*
Occlusal Landmarks –M-D and B-L cusp position relative to Class I relationship
*
Centric Cusps –B of lower & L of upper
*
Guiding Inclines –B of lower B cusp & L of upper L cusp
*
Supporting Inclines –L of lower B cusp & B of upper L cusp

Question 45

How does heavy occlusion affect implants?

Answer 45

Sakka ‘12
Literature review.
Early failure related to primary stability, surgical trauma and infection.
Late failures related to occlusal overload and periimplantitis.

Koyano ‘15
Literature review to ascertain the influence of implant occlusion on the occurrence of complications in implant treatment and the clinical considerations on overloading.

Based on the selected literature, this review explores factors related to the implant prosthesis(cantilever, crown/implant ratio, premature contact, occlusal scheme, implant-abutment connection, splinting implants and tooth-implant connection) and other considerations, such as the number, diameter, length and angulation of implants.

Insufficient evidence to establish firm clinical guidelines for implant occlusion.

Klineberg ‘12
Due to the absence of a periodontium and periodontal mechanoreceptor feedback, fine motor control of mastication is reduced with implants, but patients are still able to function adequately.

Finite element analysis data confirms load concentrations occur at the coronal bone around the upper section of the implant where bone loss is commonly observed clinically.

Load concentrations increase with steeper cusp inclination and broader occlusal table and decrease with central fossa loading and narrower occlusal table.

Recommends occlusal design follow a narrow occlusal table with central fossa loading in intercuspal contact and low cusp inclinationto minimize lateral loading in function and parafunction.

Question 46

When is splinting indicated for mobility?

Answer 46

Splinting is indicated for:
a. Increasing mobility due to bone loss (secondary trauma).
b. Restorative stability(Multiple abutting).
c. Patient comfort–confidence in function.
d. Post ortho retentionin certain perio cases
*
Splinting to prevent postop increases in mobility after osseous surgery is unjustified –mobility returns to preop levels in 6-12 mos.

Question 47

What are the indications for extractions?

Answer 47

1. Unrestorable= minimal remaining volume of dentin after caries control to predictably restore
2. Endodontically untreatable = vertical root fracture, unrestorable perforation, over instrumentation
3. Questionable Periodontal Prognosis = > 60-80% bone loss, Advanced furcal interradicular CAL and pocketing
4. Strategically not useful = 3rdmolars, malposed teeth, esthetic liability