Occlusion in periodontal practice - Dr Harshavardhan Patwal

Occlusion In The Practice of Periodontics

Dr Harshavardhan Patwal

McNeil defines Occlusion as the “Functional relationship between components of the Masticatory system, including the Teeth and the Supporting tissues, Neuromuscular system, Temporomandibular Joints and the Craniofacial Skeleton.”

Envelope of Motion

Ideal Occlusion (Dawson)

• Stable centric stops on all teeth when the condyles are in the most superior and posterior position

• An anterior guidance that is in harmony with the border movements of the envelope of function

• Disclusion of all posterior teeth in protrusive movements

• Disclusion of all posterior teeth in non working side

• Non interference of all posterior teeth on the working side with either the lateral anterior guidance or border movements of condyles

• Centric Relation: The position of the mandible when the condyles are in an orthopedically stable position

• Centric Occlusion: The position of the mandible when there is maximum interdigitation and occlusal contact between maxillary and mandibular teeth

Differing Occlusal Schemes

• Theoretically Ideal Occlusion• Canine Protected Occlusion• Group Function Occlusion• Physiologic / Non-Physiologic Occlusion• Anterior Guidance Occlusion• Mutually Protected Occlusion• Balanced Occlusion

Patients need a

balanced occlusio

n

Dentists need a

balanced view on occlusio

n

Questions that need answers

• Is occlusion a risk factor for periodontitis ?• What role does occlusion play in the

maintenance of a successfully osseo-integrated dental implant?

• Do occlusal schemes differ between natural dentitions and implant included dentitions?

• Does increased occlusal force cause Abfraction?

• Is occlusal adjustment a valid treatment option?

Trauma From Occlusion

• Trauma From Occlusion ( TFO ): When occlusal forces exceed the adaptive capacity of the periodontal tissues, the resultant tissue injury is trauma from occlusion

Synonyms for Trauma from Occlusion

• Occlusal Trauma• Periodontal Traumatism• Occlusal Overload• Traumatogenic Occlusion• Traumatizing Occlusion

Classification of Trauma from Occlusion

• Acute TFO : Results from an abrupt increase in the amount of forces

• Chronic TFO : Results from gradual changes in occlusion produced by tooth wear, drifting movement, extrusion of teeth, combined with parafunctional habits such as Bruxism and Clenching

Classification of Chronic Trauma from Occlusion

• Primary TFO : Periodontal Tissue Injury resulting from excessive occlusal forces applied to a tooth or teeth with normal support.

• Secondary TFO : Periodontal tissue injury resulting from normal or excessive forces bing applied to tooth or teeth with reduced support

Primary Secondary TFO TFO

Factors that determine whether an Occlusion is

Traumatogenic• Magnitude• Direction - Parallel to the Long Axis - Lateral (Horizontal ) / Torque

• Duration• Frequency

Criterion that determines if the occlusion is traumatic is whether it produces periodontal injury, not how it occludes.

Stages of Tissue Response to Increased

Occlusal Forces 1) Injury 2) Repair 3) Adaptive Remodelling

Stage 1 - Injury• Periodontal tissue injury occurs due

to increased occlusal forces• Under forces of occlusion the tooth

rotates around a fulcrum, creating areas of pressure and tension on opposing sides of the fulcrum

• Slightly excessive pressure stimulates bone resorption

• Slightly excessive tension causes elongation of PDL fibres and apposition of alveolar bone

Stage 1 Injury (cont’d)• With greater Pressure, the

compression of PDL fibres produces areas of Hyalinization.Further injury causes Necrosis of areas of PDL.

• Vascular changes, starting with vasostasis within 30 minutes, which may eventually lead to fragmentation of blood vessels in 1 – 7 days

• Associated with increased resorption of bone (undermining resorption)

• Greater Tension leads to thrombosis,hemorrhage, tearing of PDL and resorption of alveolar bone.

Stage 2 - Repair

• The damaged tissues are removed and new connective tissue cells, fibers, bone and cementum are formed to restore the injured periodontium

• Forces are traumatic only as long as the damage exceeds the reparative capacity.

• Buttressing bone formation

Stage 3 – Adaptive Remodelling

• If the repair process cannot keep pace with the destruction caused by the Occlusion, the periodontium is remodeled in an effort to create a structural relationship in which forces are no longer injurious to the tissues

• This results in a thickened periodontal ligament which is funnel shaped at the crest and angular defects in the bone with no pocket formation

Role of occlusion in Periodontal Disease –

Historical review• Karolyi Effect ( 1901 )• Stillman’s definition of TFO ( 1917 )• Stones and Box – Experiments on

sheep and monkeys ( 1938 )• Orban ( 1939 ) – Based on autopsy and

animal experiments described changes occurring to teeth when excessive forces were applied – describing changes that occur to sides with tension and sides with pressure.

Shortcomings of Early Studies

• These early studies had the following shortcomings

• They were primarily based on individual observations and opinions

• They lacked proper controls• The design of these studies did not

justify the conclusions drawn

Glickman’s Co-Destructive Effect

Glickman’s Co-destructive Effect

Alteration of Pathway of Inflammation

- Glickman

Formation of Infrabony Pocket

- Glickman

Glickman’s Hypothesis

• TFO may alter the pathway of inflammation to the underlying tissues.

• Inflammation may then proceed to the periodontal ligament rather than to the bone.

• Resulting bone loss would then be angular and pockets could be intrabony

Glickman’s Conclusions

• Trauma from occlusion is an integral part of the disease periodontitis rather than an unrelated disease entity and is an etiologic factor in the formation of infra bony pockets and angular or crater like osseous defects.

• Considered TFO a Co-Destructive factor in the etiology of periodontal disease

• Occlusal Adjustment is to be considered as inherent part of periodontal therapy

Waerhaug’s Plaque Front Hypothesis

• Measured the distance between subgingival plaque and the periphery of associated inflammatory cell infiltrate and the surface of the adjacent alveolar bone.

• He suggested that angular bony defects and Infrabony pockets occur when the sub gingival plaque of one tooth reaches a more apical level than plaque on an adjacent tooth

Plaque Front Hypothesis

Waerhaug’s Plaque Front Hypothesis

• Connective tissue attachment and resorption of alveolar bone around teeth was exclusively the result of inflammation associated with plaque.

• Angular defects result due to the difference in the apical migration of plaque.

Problems with Early studies

Initial studies introduced forces that were continuous or intermittent that were in one directionCreated Orthodontic type of forces

Also lot of the early studies were on autopsy specimens

Did not create Jiggling trauma that is seen when TFO is present in human

Orthodontic type of trauma

Studies with Orthodontic Forces

• Studies by Steiner (1981) and Wennstrom (1987) however demonstrated that orthodontic forces producing bodily or tipping movement of teeth may result in Gingival Recession with loss of connective tissue attachment

• This occurred at sites with gingivitis, and when in addition the tooth was moved through the alveolar proceess.

Animal Experiments-Jiggling Trauma

Rochester Group

• Used squirrel monkeys• Trauma induced by repetitive

interdental wedging• Mild to Moderate gingival

inflammation was introduced• Experiments were carried on

upto 10 weeks

Animal Experiments-Jiggling Trauma Univ. of Gothenburg Group

• Used Beagle dogs• Produced jiggling trauma by

placing cap splints and orthodontic appliances

• Induced severe gingival inflammation

• Experimental times were upto one year

Jiggling Trauma – Healthy Periodontium

Jiggling Trauma – Healthy but Reduced

Periodontium

Jiggling Trauma superimposed on teeth

with Suprabony Pockets

Jiggling Trauma superimposed on teeth with Infrabony Pockets

Conclusions of Experiments Jiggling Trauma superimposed on Teeth with Experimental

Periodontitis

• The Rochester Group concluded that Trauma superimposed on teeth with Suprabony or Infrabony Pockets

a) Caused increased loss of alveolar bone

b) Failed to produce additional loss of connective tissue attachment

Photomicrograph of teeth with and without Jiggling Trauma superimposed on

teeth with Infrabony Pockets

Jiggling Trauma superimposed on Teeth with Experimental Periodontitis-Gothenburg Group -

Conclusions

• TFO that allows adaptive alterations to develop in pressure/tension zones of the periodontal ligament will not aggravate a plaque associated periodontal disease

• In TFO were adaptation did not occur the Zone of Co-Destruction merged with the Zone of Irritation resulting in apical migration of the dento-gingival epithelium and Aggravation of Periodontal Disease

Animal studies – Yoshinaga 2007

Distribution of RANKL in rat periodontium during

Lipopolysaccharide induced inflammation with and without

Occlusal Trauma

Yoshinaga 2007

• Lipopolysaccharide(LPS) was injected rat gingiva to induce inflammation. Occlusal trauma was introduced by the placement of gold inlays.

• The study found significantly more RANKL+ve cells in the LPS and in the LPS + trauma groups

• There was significantly more RANKL+ve cells in the LPS + trauma group than the other two groups

Yoshinaga 2007

• This report demonstrated that LPS induced inflammatory bone resorption with traumatic occlusion, is more than destruction induced by LPS or traumatic occlusion alone.

• The study also hinted that occlusal trauma influenced the spread of LPS induced inflammation to the furcation region .

Stress induced regulation of mRNA Expression of Osteoprotegerin

• Tsuji in 2004 reported that the combination of LPS and mechanical stress reduced the expression of Osteoprotegerin in periodontal ligament cells in vitro

• These studies seem to indicate that occlusal stress in association with LPS induced inflammation upregulates factors that promote increased bone resorption

Clinical Studies - Ethical Issues

• Problems associated with non treatment of Diagnosed Periodontal Diseases

• Therefore difficulties in formatting a RCT

World Workshop of Periodontics 1996 recognized that “ Prospective studies on the effects of occlusal forces on progression of periodontitis are not ethically acceptable”

Therefore most studies in humans have been Descriptive or Retrospective

Meta analysisSystematic reviews

In vitro research

Animal researchIdeas, editorials, opinions

Case reports

Case control studies

LEVELS OF CLINICAL EVIDENCE

Randomized controlled trialsCohort studies

1

2

3

4

5

Clinical Trials – Philstrom 1986

• Studied the association between TFO and Periodontitis by assessing a series of clinical and radiographic features of Maxillary 1st molars

• They concluded that teeth with increased mobility and widened periodontal ligament space had in fact, deeper pockets, moe attachment loss and less bone support than teeth without these symptoms

Clinical Trials – Burgett 1992

• Studied the effect of Occlusal Adjustment in treatment of Periodontitis

• 50 patients following examination at baseline were treated with Root Debridement and Flap Surgery, out of whom 22 received Comprehensive Occlusal Therapy.

• On re-examination those with Occlusal Therapy had on average 0.5 mm greater Attachment Gain than those who did not receive occlusal therapy

Effects of Occlusal Discrepancies on the

Progression of Periodontal Disease• Nunn and Harrel in a series of studies

published in 2001 and 2004 reported that two specifically defined occlusal parameters consisting of either an occlusal discrepancy between centric relation occlusion and centric occlusion and/or a non working side contact.

• These studies reported that these occlusal discrepancies are an independent risk factor for the progression of periodontal disease with periodontal treatment resulting in improved outcomes when compared with patients with untreated discrepancies.

Association of Occlusal Contacts with Pocket

Depths –Nunn & Harrel 2009• The following associations of deeper

pocket depth with occlusal prematurity was noted

• In CRO (0.89mm, p < 0.0001)• Post. Protrusive

contact( 0.51mm,p<0.0001)• Balancing contacts

( 1.01mm,p<0.0001)• Combining balancing &working side

contacts (1.13mm,p<0.0001)

Nunn & Harrel 2009

• Multiple types of Occlusal prematurities were shown to be associated with deeper probing pocket depths and an increased assignment of a less than “Good” prognosis

• They suggested that treatment of Occlusal Discrepancies as a routine part of periodontal treatment may be indicated

Contradicting Studies

• Rosling et al (1976) – Infrabony pockets associated with hypermobile teeth exhibited the same degree of healing as adjacent firm teeth

• Jin and Cao (1992) – Concluded that there were no significant differences in probing depth, clinical attachment levels or alveolar bone height, when comparing teeth with and without abnormal occlusal contacts

Contradicting Studies

• Bernhardt et al (2006) investigated the potential associations between dynamic occlusal interferences and signs of periodontal disease in posterior teeth

• They demonstrated a weak relationship between non working side contacts and increased probing depth and attachment loss.

What do we Know?• Trauma from occlusion does not

initiate gingivitis or periodontitis

Literature review though not unambiguous seems to suggest the following:

• Occlusion may be a risk factor in the progression of periodontal disease

• Healing following surgical treatment of periodontal disease may be more advantageous in Non-mobile Teeth than in Mobile teeth

Evidence Based Approach for Decision Making

Newman et al : Ann Periodontol 2003

• Is Objective • Is Scientifically Sound• Is Patient Focussed• Incorporates Clinical Experience• Is Thorough and Comprehensive• Uses Transparent Methodology

Role Of Occlusion In Implant Dentistry

Occlusal Considerations – Implant Dentistry

• Main difference between a tooth and implant is the lack of Periodontal Ligament

• There are no proprioceptive nerve endings

• The Blood Supply is less• Implants have very limited capacity to

displace axially ( 3 – 5 µm)

Consequences of Biomechanical Overload

• Early Implant Failure• Early Crestal Bone Loss• Intermediate - Late bone loss &

implant failure• Screw loosening/Un-cementation • Component/Porcelain Fracture• Peri Implantitis (from crestal bone

loss)

Implant Protective Occlusion

• No premature occlusal contacts/inteferences

• Influence of Surface Area• Mutually Protected Occlusion• Implant body angle to occlusal load• Cusp angle to crown • Cantilever – Horizontal/vertical

Offset• Implant Crown Contour• Protect the weakest component

Proprioception in Implants

• Teeth identify inteferences at approximately 20µm.

• An implant opposing a natural tooth detects an interferences at 48µm

• An implant opposing an implant detects an interference at 64µm

• When a tooth opposes an implant supported overdenture the awareness is at 108µm

Occlusion on Natural Teeth and Implants

Occlusion on Natural Teeth and Implants

Implants do not display Immediate Horizontal Mobility. With Heavier Forces mobility ranges from 10 to 50µm.

Axis Of Implant To The Load

• Non – Axial / Off Axis loading is harmful

• Cantilevered Loading is harmful• Control the Horizontal Force with

Cusp Incline• Reduce the area of the Occlusal

Table

Occlusion and Abfraction

• Abfraction – Coined from two Latin words

Ab – Away Fractio – Breaking ie. Breaking Away Term coined by John Grippo in 1991

Abfraction

• Definition: The Pathological loss of tooth substance caused by Biomechanical Loading Forces that result in flexure and failure of enamel and dentine at a location away from Loading

Abfraction - History

• In the early ‘80s McCoy questioned the role of tooth brush abrasion in what had previously been considered cervical abrasion

• He postulated using Engineering Studies that tensile stress from mastication and malocclusion broke the Hydroxyapatite chemical bonds making them susceptible to toothbrush abrasion and chemical erosion

Tooth Flexure Model – Tensile strsses concentrated

at Cervical areas

Abfraction with Gingival recession

Treatment of Abfraction

• Education• Occlusal Equilibration• Guard/Splint Therapy

Occlusal Equilibration

•There is a tendency to think of occlusal adjustment solely in a negative sense.

•Equally important purpose is to provide Functional

•Stimulation necessary for the preservation of Periodontal Health.

Relationship between Occlusal Force and

progression of Periodontal Disease – Takeuchi 2010

• Prognosis of teeth in maintenance phase was significantly affected by Low Occlusal Forces ( p < 0.006)

• Suggested that Low Occlusal Forces might be possible Risk Factor for Periodontal Disease Progression

Biologic Basis of Occlusal Function

• Physiologic Occlusion is present when no signs of Dysfunction or Disease are present and no treatment is indicated

• Non-Physiologic Occlusion is associated with Dysfuction or disease due to tissue injury

Criterion that decide whether the occlusion is traumatic is whether it produces periodontal tissue injury, not how the teeth occlude

Terminologies• Intercuspal Position• Muscular Contact Position• Excursive Movement • Laterotrusive Side• Mediotrusive Side • Protrusion• Retruded Position• Guidance• Interference

Guidelines for Therapeutic Occlusion Natural Dentition

1. ICP – Bilateral , simultaneous, well distributed contacts on posterior teeth providing arch stability.

2. RCP – The RCP – to ICP relationship is less than 1mm along a forward (symmetrical ) path measured at incisal levels.

3. Vertical Stops – Stable multiple contacts on the posterior teeth providing individual tooth stability. No buccal – lingual thrust or impact to any tooth in closure to ICP.

4. Laterotrusive Excursions – Smooth movement with diclusion controlled by canine and first premolar on thelaterotrusive side .No contacts on mediotrusive side.

Guidelinesfor TherapeuticOcclusion

Natural Dentition – Cont’d5. Protrusive Excursions – Smooth

movements with multiple contacts bilaterally distributed on the anterior teeth

6. Interfernces – Freedom from non working side contacts. Freedom from posterior contacts on protrusive excursions. Freedom from single tooth molar contacts on any excursion.

7. Acceptable free way space – The normal range is 1-4mm . If the free way space measures more and there are symptoms it must be treated

Guidelines for Occlusion in Dental Treatment

Subjective to response to occlusion

• Lack of unpleasntness or untoward awarness concerning in dental occlusion.

• Acceptable - Freeway space - Speech articulation- Chewing ability- Mandibular position

Recommended Materials for Identifying and Making Tooth Contact and Contact Movement

Products

• Occlusal registration strips• Occlusal wax indicator• Marking ribbion ,red,green• Articulating paper, Blue

Correction of Retrusive Prematurities

MUDL Rule

• Grooving• Spheroiding• Pointing

Occlusal Adjustment

Grooving• Entails restoring the depth of

devolopmental grooves ; Done with tapered cutting tool until its desired depth is attained.

Occlusal Adjustment Spheroiding• Consists of reducing the supracontact

while restoring the original tooth contour;Effort made to preserve the occlusal height of the cusps.

Occlusal Adjustment Pointing• Consists of restoring cusp

point contours ; Done by reshaping the tooth with rotating cutting tools.

Schedule of Coronoplasty

1. Remove retrusive prematurities and eleminate the deflective shift from RCP to ICP.

2. Adjust ICP to achieve stable ,simultaneous, multipointed, widely distributed contacts.

3. Test for excessive contact (fremitus) on the incisor teeth.

4 Remove posterior protrusive supracontacts and establish contacts that are bilaterally distributed on the anterior teeth.

Schedule of Coronoplasty

5. Remove or lessen mediotrusive interferences.

6. Reduce excessive cusp steepness on the laterotrusive contacts.

7. Eliminate gross occlusal disharmonies.

8. Recheck tooth contact relationships.

9. Polish all rough tooth surfaces.

`

Identifying Retrusive Prematurities –MUDL

Rule

Group Function Guidance

• Most favorable alternative to canine guidance

• Several teeth on the working side contact during laterotrusive movement

• Most desirable consists of the canine, premolars and sometimes mesio – buccal cusp of first premolar

Mutually Protected Occlusion

• A mutually protected occlusion is an occlusal scheme in which the anterior teeth protect the posterior teeth, and vice versa.

• Anterior guidance of an implant should be as shallow as practical

• On lateral excursions the posterior teeth are discluded by anterior segment of jaws

Forces on Implants need to be Axially

Directed

Maxillary Stabilization Appliance

• Remains the most universal and effective long term means of interfering with the effects of bruxism.

• Aim of the appliance is to protect the tooth surface and dissipate forces built up in the mucoskeletal system through bruxism.

• Appliance results in an immediate reduction of masseter and temporalis muscle activity levels.

Criteria for Maxillary Stabilization Appliance

Occlusal Criteria • Appliance : stable• RCP,ICP : stable ,multipointed , widely

distributed contacts.• ICP: Posterior vertical steps in firm

contact;incisor teeth in slight infracontact.• RCP-ICP relationship : in the same sagittal

plane. • Smooth gliding contact in all excursions.• MCP : stable , repeatable.

Role for Periodontal Splints?

Role for Periodontal Splints?

Role for Periodontal Splints?

Conclusions

• There is no scientific evidence to show that trauma from occlusion causes gingivitis or periodontitis or accelerates the progression of gingivitis to periodontitis.

• The periodontal ligament physiologically adapts to increased occlusal loading by resorption of the alveolar crestal bone resulting in increased tooth mobility. This is Trauma from Occlusion and is reversible if the Occlusal force is reduced.

Conclusions• Trauma from Occlusion may be a co-

factor which can increase the rate of progression of an existing periodontal disease.

• There is a place for Occlusal therapy in the management of periodontitis,

• Occlusal therapy is not a substitute for conventional methods of resolving plaque-induced inflammation.

Conclusions

• A Comprehensive Knowledge of the Dynamics of Occlusal Loading Forces on Peri-Implant tissues is the most significant factor in the successful rehablitation of patients with Implants

Thank You