functional and esthetic restoration of the worn dentition

Functional and Esthetic Restoration of the Worn Dentition

Leonard A. Hess, DDSSenior Faculty, The Dawson Academy Private Practice, Monroe, NC

Ontario Dental Associtation ASM 2015

Thank You!!!!!

What do we think about when someone says “The Worn Dentition”???

Please don’t break anything if I restore a tooth.

Treatment Planning is very Important!!!!!

What happens when this guy walks in the door???

This is someone near the end point of a process. Really????

Do you have people who wonder why these things happen?

Have you seen excessive wear in young patients?

This is where it starts. And where we can make a difference!!!!

Can we prevent people from getting worse?

Would you want to know?

What are the ramifications of not telling people?

Have you ever had a restoration break? I have, more than once!

ARE THESE INCISAL EDGES

WORKING???????

We must be good at asking one question......

We must become an expert at answering this question!!

However..........Why????

Complete Treatment Planning is the goal...

‣“90% of cases that fail, fail not during the restorative phase but in the treatment planning phase.

1. Proper esthetics (or form) is derived from proper function. Not the opposite.

2. Not properly following (or incompletely following) function can lead to failed function and failed form.

Consider This....

Consider This....

3. If you are restoring teeth due to wear and breakage......... the system they are in is not working!

4. As teeth wear and break down, they are changing position. Often compounding the issue.

Occlusal Disease‣most common dental disorder ‣contributing factor to eventual tooth loose ‣ reason for needing extensive restorative dentistry ‣ factor associated with discomfort within masticatory system

structures ‣ factor in instability of orthodontic treatment ‣ reason for tooth sorness/hypersensivity ‣most common missed diagnosis leading to endo ‣most undiagnosed dental disorder

1#From “Functional Occlusion From TMJ to Smile Design”, Pete E. Dawson, DDS

Signs of instability

‣ Teeth with wear, mobility or migration

‣ Sore muscles of mastication

‣TM Joint instability

So Why Does This Happen?

Abrahamson IDJ 2005

Grippo, Simring, Coleman JADA Vol 135 2004 J Esth Rest Dent Vol 24 2012

Tripathi J Dent Med Sci 2014

Fernandes J Pros Dent 1991

Attrition-Tooth to tooth friction

(Parafunction? Centric Relation/Maximum Intercuspation interference?)

Abrasion- Friction between tooth and exogenous agent. (Toothpaste, Pencil, Tobacco)

Corrosion-Chemical or electrical Cupping, thinning. (Soda, aspirin powders, fruit mulling, gastric acids, etc.) Anterior vs. Posterior?

Abfraction- Concentrated stress transmitted thru occlusal loading forces

Dr. John Grippo coined the term in the 1990’s

Loaded teeth show a loss of enamel 10x greater than unloaded teeth.

Fernandes study shows enamel rods run parallel to the long axis, not perpendicular as thought in the past.

Tripathi in 2014 J of Dent. Med. Sci.

Abfraction= FORCE + ABRASION/CORROSION

9 years later!!!

Pathologic Wear

Wear is a Multi-Factor Issue

AttritionAbrasionCorrosion

Occlusal Stress Parafunction

Normal wear is 10.7 microns per year (.000039 inch)

Larson TD Northwest Dent. 2007

Most will be a combination of two or more issues

Whatto

consider?

Teeth and Periodontal Structures

Position

Esthetics

Functional Arrangement

Current Condition

They all must be respected. What if you ignore one or more of the above?

Restoration Selection

It is or responsibility to determine where the teeth go in space

What material will be used

Into what functional relationship they are placed

What specialists should be involved

It can be an overwhelming burden!!!

“Determination of precisely correct incisal edges is the

second most important decision a dentist must

make regarding occlusion. Centric relation is first.”

Need------------------

Want

We must be cautious of these two important aspects working against each other.

How do we make this Easy and Predictable?????

Checklists!!! And using them consistently.

‣Reshape ‣Reposition Dentition ‣Restore ‣Reposition Bone

Treatment options:

Treatment options: Reshape • Reposition • Restore • Reposition boney segment

10 Step 3D Treatment Planning Checklist

Step 1: Choose Condylar Position

(Based on Restorative TMJ-Occlusal Examination)a.) Maximum intercuspationb.) Centric Relationc.) Treatment Position

Step 2: Go Tooth by Tooth

With casts, restorative chart, periodontal probings & photos, and mark hopeless teeth, questionable teeth, and teeth that need to be restored (crowned or onlayed) due to weakness or breakdown.

Step 3: Evaluate Maxillary, Mandibular Occlusal Plane

Use photographs (full face, profile, and smile shots) & mounted casts.

Step 4: Choose Vertical & Horizontal Position of Mandibular Incisal Edge

Step 5: Choose Vertical & Horizontal Position of Maxillary Incisal Edge

Step 6: Choose Vertical Dimension of Occlusion

Step 7: Provide Equal Intensity Stops

Step 8: Eliminate Balancing & Working Interferences

Step 9: Harmonize Anterior Guidance

Step 10: Final Functional-Esthetic Check

©2011 The Dawson Academy • www.TheDawsonAcademy.com

What we do in the lab

LABLab communication checklist

We must communicate: Condylar position Vertical dimension Vertical and horizontal position of the mandibular incisal Vertical and horizontal position of maxillary incisal edge Lingual contour of maxillary incisors (EOF) Precise Margin Placement Preparation Shade Desired shade and contour

Required Records for Effective Lab Communication: Facebow/ or facebow preservation model Final impression Opposing impression or model Bite registration to mount provisional model/models Bite registration to mount die model/models Dr & patient approved provisional impression/model Full series of preop photos/provisional photos/dentin shade/desired shade tab Detailed laboratory prescription Request for custom guide table & incisal matrix Complete treatment plan (if cases to be completed in phases)

Following the checklists allows a systematic approach to treatment planning. Which leads to predictable success.

Comprehensive Examination and Records

1.

2Comprehensive

Treatment Planning to determine appropriate

treatment options

Provisional Prototypes3

Definitive Restorations4

Esthetically, Functionally or Both

General

patientsSpecialty patients

Two Patient Populations

Size, shape, contour, position work Not working

How do we identify the “Specialty” from the “General” patient’s?

‣ They will be the ones who:

‣ 1.) Desire an esthetic change.

‣ 2.) Present with occlusal disease (signs of instability).

‣ 3.) Need extensive dentistry

‣ 4.) Or have a combination of the above.

In Dental school we were trained to treatment plan only the former.

Moving tooth by tooth, making the final decision with regards to the definitive restoration.

The problem:

Definitive Restorations

(In Our Mind) 2D tx

planning

When changing tooth position, size or contour requires a more thorough process.

Definitive Restorations

(In Our Mind) 2D tx

planning

(In Wax) 3D tx planning

Prototype Provisionals

Understanding the System in Which Teeth Function

Condition

What treatment position?

Effect of treatment?

Most problems occur when we try to segment our plans. We loose sight of the big picture.

To identify ‘General’ from ‘Specialty’ patients it is incumbent on the Restorative Dentist to do a thorough examination.‣Oral cancer examination ‣Periodontal examination (full probing) ‣Restorative charting ‣TMJ Occlusal Examination ‣Full mouth series of x-rays ‣Potential for additional records (mounted diagnostic casts or imaging?)

We must make a proper diagnosis to identify the weak link in the system.

The Teeth

The Joint

The muscles

The Periodontium

Our fight is against either bacteria, force or both.

The components of the TMJ-Occlusal Examination‣The History (7 questions)

‣Range of Motion Test

‣The Centric Relation Load Test

‣TMJ Doppler Ausculation/JVA

‣Muscle Palpation

‣Evaluation of the Dentition for wear, mobility and migration

‣ Imaging

Goals of TMJ-Occlusal Examination‣Assess “restorability” of joint.

‣Make Diagnosis regarding level of parafunctional activity.

‣Determine if Occlusal Therapy is required for this patient.

What you need...‣A New Patient/Records System in your practice

‣A process to evaluate the TM Joint/occlusion & dental structures

‣A semi-adjustable articulator, that accepts a facebow

‣A quality digital camera

‣A well trained team member dedicated to the ‘records gathering process’

1.) History: Seven Questions‣Have you ever had or been diagnosed with a problem with

either jaw joint?

‣Does your jaw joint click, pop or make noise when you open and close?

‣Do you have pain or tenderness in your jaw joint when you open, close or chew?

‣Has your jaw ever locked open or closed?

‣Do you have frequent headaches? If so, how often?

‣Do you Clench or Grind your teeth, or ever been told that you do?

‣Have you ever had trauma to your chin or jaw?

2. Range of Motion Test

‣Opening: 40-55 mm

‣Protrusion: 8-12mm

‣Lateral: 8-12mm

3. Centric Load Test ‣Key Question:

‣“Is there any sign of tension or tenderness in either joint?”

1. Recline the patient so that your arms are parallel to the floor.

Correct Position Incorrect Position

When a patient is not reclined enough, the operators arms will be too high resulting in a bowed wrist position. This makes it nearly impossible to “turn the doorknob”, and often promotes distalization of the mandible as the operator then pulls back on the mandible.

2. Point the chin of the patient up.

Correct Position Incorrect Position

A chin up position allows easier placement of the hands on the mandible, and easier visualization for the operator. This will also prevent the patient from protruding their mandible.

The Dawson Academy Bimanual Manipulation Checklist

If the disk is displaced, compression of the retrodiskal tissue will lead to pain or discomfort

Tension and tenderness will result from muscle tension keeping the condyle from completely seating

Don’t start out with the firm pressure first. You will shock the muscles and they will not cooperate.

If you have a reason to wonder, figure it out.

1. Unreleased pterygoid 2. Medial pole displacement 3. Retrodiskitis

4.) Joint Sounds

‣TMJ Doppler Auscultation

‣Joint Vibration Analysis

Doppler Auscultation

A healthy joint will be quite on rotation and translation

It is simple, efficient and easy to use

Noise on translation is not a deal killer. Noise during rotation should bring caution and perhaps trigger imaging

if restorations are necessary.

You get to demonstrate and document for the patient

‣Masseter

‣Temporalis

‣Medial Pterygoid

‣Lateral Pterygoid (resistance check)

‣Digastrics/suprahyoids

5.) Muscle Palpation

6.) Evaluation of dentition for:

‣Tooth Wear

‣Tooth Mobility

‣Tooth Migration

Recognize Instability

Wear beyond normal Tooth movement that is not wanted

Excessive mobility

When a lack of functional harmony exists between the muscles and the teeth........the teeth will lose this battle. Often times the joint will also

show ill effects from this relationship.

Sore Muscles

Unhealthy Joints

Examination of the Occlusion and Teeth

Is there a CR/MI discrepancy?

Where? How much? Which direction?

Is there tooth wear, mobility, migration?

Look for Functional Patterns

Cows Rats

Is it Parafunction?

This does not mean that every patient becomes a full mouth rehab candidate.

We learn to recognize

Instability Stability

Dangerous

Crazy People

TMD

Bruxers

Concept of Collateral Damage

“The point that should not be missed is that masticatory system disorders are rarely ever confined to a single structure. There will almost always be collateral effects from disorder in the joints, the teeth, or the muscles. These will be evident as signs or symptoms. Careful observation will usually show that there is a chain of cause-and-effect reactions as one disorder leads to another.”

-Dr. Peter Dawson Text: Functional Occlusion

From TMJ to Smile Design

The joint can be in 3 possible conditions

1. Structurally intact

2. Altered at the lateral pole

3. Altered at both poles

“If the TMJ’s are not stable, the occlusion will not be stable, so it is a risky proposition to undertake occlusal changes without knowing the condition of the TMJ’s.” -

Dr. Dawson


Let’s talk about function!

Goal #1: TMJ’s Healthy and the Condyles In Centric Relation

Let’s talk about Centric Relation

What it isn’t

Forced

Unnatural

Dependent on teeth

Mythical

What it is.

Functional Occlusion From TMJ to Smile DesignDr. Peter Dawson

“Centric Relation is the relationship of the mandible to the maxilla when the properly aligned condyle-disk assemblies are in the most superior position against the eminentiae irrespective of vertical dimension or tooth position.

At the most superior position, the condyle disk assemblies are braced medially, thus centric relation is also the most midmost position.

A properly aligned condyle disk assembly in centric relation can resist maximum loading by the elevator muscles with no sign of discomfort.

TMJ Examination

Bi-concave self positioning disk

We must understand the anatomy first

We don’t have disk problems, we have disk position problems

The Temporomandibular Joint

Posterior Attachment

Retrodiscal tissue

Superior Belly of the lateral pterygoid

Inferior Belly of the lateral pterygoid

Centric Relation

It is the stable axial position of the mandible

The only position that will allow an interference free occlusion

It is not about teeth. But don’t lose sight of their influence

It is about allowing muscle comfort and coordination

Allows an anatomic, and physiologic position to begin restoration of teeth

In CR the load is on the Medial Pole

In rotation, the force stays centered on the medial pole and in centric relation. When movement transitions into translation, the force transfers to the lateral pole.

What happens when the joint can’t seat?

For many people it is simple incline interferences that keeps them from being comfortable, and that can cause

us so many problems

CR gives us a tripod of stability

2 seated Condyles + Anterior contact = Stable Tripod

I Consider it the 8th wonder of the world

It is a source of stability and the solution to so many problems that wet fingered

dentists face every day

Goal #2: Equal Intensity Stops on all Teeth (or a Substitute)

(Remember Goal 1 has Been Satisfied)

This is a Key Point in Creating Stability in a Patient

Even, stable holding contacts on all teeth with the condyles in Centric Relation

Exception to the rule

Neutral Zone

“More than any other factor, the neutral zone programs the envelope of

function. The neutral zone is a major determinant of how teeth erupt. And it is

the position of the anterior teeth that

influences the neuromuscular

programming of functional jaw movements.”

Goal #3: No Posterior Tooth Contact in Excursive Movements

Get The Canines Doing Their Job

“The success or failure of many

occlusal treatments

hinges on the correctness of

the anterior guidance.”

Stability

Anterior Guidance that immediately separates the posterior teeth in a lateral or protrusive movement. And which allows these excursive movements within the envelope

of function. The lingual anatomy must be concave enough for the EOF as well.

Neff

Canine Guidance shuts down the elevating muscles, protecting the posterior teeth.

Influence of altered occlusal guidance on masticatory muscle during clenching. Okano, Baba, Igarashi J Oral Rehabil. 2007;34(9): 679-684

Anterior Guidance: its effect on electromyographic activity of the temporal and masseter muscles. Williamson, Lundquist. J Prosthet. Dent. 1983; 49(6): 816-823

Influence of group function and canine guidance on eletromyographic activity of elevator muscles. Manns, Chan, Miralles. J Prosthet Dent. 1987; 57(4): 494-501

Effects of occlusal contact on the level of mandibular elevator muscle activity during maximal clenching in lateral positions. Shinogaya, Kimura, Matsumoto J Med Dent Sci. 1997; 44(4): 105-112

Mansour RM, Reynik RJ, J Dent. Res (1975) 54:114-120

Bite force differs by a factor of 9!!!!

Create posterior teeth the patient cannot rub.

Three reasons posterior teeth interfere or rub.

1.) Poor/bulky posterior morphology.2.) Lack of anterior guidance.3.) Condyles that are not seated.

In an ideal world, the patients occlusal contacts would be in harmony with a seated joint

position.

The reality is, mostof our patients do

not have this.

Interferences to centric relation,

can cause posterior teeth to

rub.

Anybody see teeth that look like this?

Goal# 4: Anterior Guidance in Harmony with the Envelope of Function

Ever have a patient who can’t get comfortable?

“When restoring maxillary anterior teeth, the lingual

contours should be in harmony with the EOF from the CR contact point to the incisal

edges.”

long term stabilitypredictable comfort

PRINCIPLE

best phoneticsbest esthetics

protection of back teeth

to insure...

MUSTget this right

The anterior guidance is in harmony with the envelope of function. (CR contact to incisal edges)

Make Restoration that work for the patients EOF

Envelope of Function

Excessive Contour

Lines in the frontDots in the back

Envelope of function is influenced by: Centric relation

Need for long centric Correct Incisal Edge Smooth Protrusive Lateral Disclusion

EOF

EOF can only be refined in the mouth!!!!!!

Dawson

Don’t forget about the lower teeth. (The hammer)

How do we work with this and meet our goals?

Lower Incisal Edge Position

Lower Incisal Edge Position

Occlusal Plane

Curve of Spee

Occlusal Plane

Curve of Wilson

Function of the anterior teeth

Determination of Lower Incisal Edge Position And Contour Is The FIRST Decision That Must

Be Made Regarding The Whole Occlusal Scheme After Centric

Relation Has Been Verified.

“The mandible does have favored pathways of

function. And if teeth interfere with these favored pathways, there will be a price

to pay in deformation or dysfunction. The weakest

link will be the prime focus of the damage.”

What does it look like when EOF isn’t working?

Where do we go now?

How much damage has been done?

“I want my veneers replaced!”

Where We Place Incisal Edges Influences Excursive Movements and Envelope of Function!!!!

So how do we decide where to place them????

“Determination of precisely correct

incisal edges is the second most

important decision a dentist must make

regarding occlusion. Centric

relation is first.”

The dentist will pay great attention to the vertical length of anterior teeth. The horizontal position of the incisal edge is commonly overlooked and left to chance. Yet the horizontal position can alter the perceived length greatly.

We must appreciate the 3-dimensional system in which teeth function. Failure to do so will lead to many esthetic, patient comfort, and functional failures.

Creating Esthetic and Functional Incisal Edges

1Determination2Communication Quality control

Verification3

Restoration of the Incisal Edge

Length (Vertical Incisal Edge)

Central Incisors: Average 11 mm in length

Try to make them fit the smile line, fill the display zone, do not violate functional parameters or phonetics

Length

The smile line follows or compliments the lip line

Rest Position

Vig and Brundo determined women show an average of 3.4mm at rest and men 1.91mm at rest

“E” position

Incisal edge approx. 50 to 60%

Length Review

1. You need to fill your canvas. Most people will have central length of 10 to 11mm

2. Do not alter phonetics (Cross into the dry portion of the lip)

3. Do not alter function4. Width of the tooth will often help to dictate the ideal

length .7 to .8 of length5. 2 to 3 mm of tooth show at rest 6. About 60% in “E” position

Incisal Edge Position (Horizontal)

--Keep the teeth in the neutral zone

--Edge should line up with inner vermillion boarder of lower lip

--it must fit within the patients envelope of function

--the position is estimated during our diagnostics, but patient tested with our temporaries

--this is why the lab needs impressions of your temps

The tip down shot

The 90 degree smile shot

How do I know if I messed up?

--teeth feel too dry, or lip hangs-up upon closure

--the patient has a new speech impediment involving “f” words

--you can keep the temps on

--pt complains their mouth muscles feel tired, “my teeth feel long

--porcelain chipping and debonding problems

--problems saying “s” sounds

--restorations feel like they are hitting first in the arc of closure

--fashizzzzell

Neutral zoneEnvelope of function

Esthetic Factors That Relateto the Incisal Edge

Length to width

80%

Width to length ratio

Create ideal length based on the width of existing tooth

Anterior Dominance

The golden proportion

.6 1.0

1.6

The midline

philtrum

Incisal plane

Beyer and Lindauer--- 2mm is the threshold for noticing a midline deviation. Nose and maxillary midline were the two most recognized deficiencies

Incisal Embrasures

Embrasures get wider and taller as you move distally

Central embrasure will be the smallest

Incisal Embrasures

Contact points

Gingival Form Get the tissue healthy

Tissue tells the story. Be smooth.

Gingival FormIdeal

Gingival FormLeast Favorable

Cervical Embrasures

The older the patient the harder it is to have ideal cervical embrasures

How do I avoid black triangles?

Tarnow says that the distance from the bone to the contact point cannot be greater than 5.0mm. If it is less, it will fill in.

Preserve your papilla people

Support the tissue

anatomic contouring

Don’t risk losing the one you have

Goals of the TMJ Exam: ‣Assess the health of the TMJ

Signs of Instability: • Medial Pole issues • DJD

TMJ-Occlusal ExaminationNegative Occlusal Exam Positive Occlusal Examination

Work in Patient’s Habitual Occlusion (Maximum Intercuspation)

Signs of Instability: • Tooth wear/erosion • Tooth mobility • Muscle pain • Occluso-muscle pain • Lateral Pole issues

Equilibrate/Reposition/ Restore/or Orthognathic to Centric Relation with ideal occlusal scheme

Verifiable CR Treat TM Joint. Must be stable before restorative phase “Treatment Position Approach”

Non-verifiable CR

No signs of Instability: • Healthy TM Joint

1 2 3







Non-verifiable CR


1 2 3

Specialty patients

Photographic Full Series

©2013 The Dawson AcademyUpper Occlusal Lower Occlusal

Right Lateral Retracted(Teeth Apart)

Front Retracted(Teeth Apart)

Left Lateral Retracted(Teeth Apart)

Right Lateral Retracted(Teeth Together)

Front Retracted(Teeth Together)

Left Lateral Retracted(Teeth Together)

Right Lateral Retracted(Close Up)

Front Retracted(Close Up)

Left Lateral Retracted(Close Up)

Rest Position ‘E’ Position Tipped Down Smile Profile Smile

Right Lateral Smile Left Lateral SmileFull Smile

Full face Profile Face Face, Lips Retracted

1.

4.

11.

14.

17.

7.

2.

5.

12.

15.

18.

20.

8.

3.

6.

13.

16.

19.

21.

9. 10.

‣ Face bow mounted, CR articulated models

‣ Photographic Full Series

Additional Records







Non-verifiable CR


1 2 3







Non-verifiable CR


1 2 3

Specialty patients

Why do we need a facebow? What does it do?

It provides the correct arc of closure associated with the condylar axis of

rotation.

Because a CR record is an open bite record! It still needs to be closed into MI.

Recording the correct axis allows us to open or close the vertical dimension

without a change from CR

That is why unmounted casts or casts on a flap articulator are useless

Ever wonder why some crowns need so much adjustment than others!

Should we use the eyes to level?

This is not a facebow.......mmmmkay.

functional and esthetic restoration of the worn dentition

Health & Medicine

teeth wear

pathologic wear wear

j of dent

excessive wear

tooth sornesshypersensivity

signs of instability

unloaded teeth

fernandes j pros dent