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5 Occlusal Considerations in History, Examination, and Treatment Planning

5 Occlusal Considerations in History, Examination, and Treatment Planning

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302



R. G. Stevenson III and A. Agnihotry



15.5.2 Acceptable Occlusal Vertical Dimension (OVD)

The OVD cannot be corrected in most cases without an impact on the amount of

display of the anterior teeth while at rest (repose) and smiling. Although OVD corrections may be indicated due to loss of tooth structure in the posterior teeth, it is

incumbent on the clinician to determine what effect this will have on the anterior

component of the teeth with respect to aesthetics. There are numerous instances

where the OVD simply cannot be corrected without creating unwanted or unnatural

display of the anterior teeth. The desire to correct the OVD to improve the occlusal

pathways and occlusal planes may need to be considered more carefully prior to

initiating a major reconstruction. It may create a more ideal occlusion, however,

with undesirable aesthetics. It is important to note that for most patients, they are

driven by aesthetics, not occlusion. The clinician must consider a reconstruction

focused on facial aesthetics and work from this when considering functional (occlusion), biomechanical (structural), and periodontal treatment planning.



15.5.3 Acceptable MI Position (MIP) and Centric Occlusion (CO)

Very few individuals will have an MIP coincident with the condyles in a fully seated

position (centric relation). An occlusal slide from the first point of contact (centric

occlusal contact) to MIP of <2 mm with intact proprioception is acceptable for the

vast majority of patients. A CR-MIP slide only becomes an issue when it is large or

when the patient develops symptoms which make the MIP position unacceptable. In

such instances, further diagnostic tests are indicated, including a comprehensive

TMJ examination, muscle testing, and centric relation mounting/evaluation of casts.

The use of deprogrammers (anterior bite planes) and monitoring of symptoms are

critical to obtain a stable and pain-free position of the joints and teeth. The treatment

may include occlusal equilibration/restorations in cases of occlusal dysfunction and

orthodontics/surgery/rehabilitations in cases where movements of the anterior teeth are

constricted (constricted chewing patterns or constricted envelopes of function) [28].

Preferably centric occlusion and MIP are coincident; in other words, when the

jaws are in the superior midmost and anterior braced position (CR), the teeth are

able to achieve a comfortable MIP.  When altering occlusal vertical dimension

(OVD), or treating cases of occlusal dysfunction, this is a primary objective of

achieving a stable (and successful) occlusion.



15.5.4 Occlusal Schemes [Acceptable Anterior Guidance (AG) or

Group Function (GF)]

Single Tooth Implant

• Incisors: To maintain good contacts and a suitable emergence profile, light contacts on the marginal ridges are acceptable in maximum intercuspation (MIP),

with little or no contacts with protrusive movements.



15  Implants in the Aesthetic Zone: Occlusal Considerations



303



Fig. 15.1 

Narrow occlusal

table of premolar

to reduce

shearing forces

from excursive

(left). An

occlusal table of

conventional

restorative crown

compared to

implant

supported crown

(right)



• Canines: The canine should not contact heavily in maximum intercuspation

(MIP). The canine should not be used for canine guidance (laterotrusive or protrusive movements), and a group function scheme should be established with

premolars, so that no shearing forces act on the implant in unfavorable non-axial

directions. On protrusive movement, a light contact is acceptable to maintain the

aesthetics, but care should be taken that it is shared with all the anterior teeth, so

that there is no undue force on the canine, which could lead to its failure.

• Premolars: For premolars, the cusps ridges involved in contact areas should not be

bulky in order to minimize any possibility of contact away from the center of the

restoration, to direct forces linearly in the center of the implant. With a narrow

occlusal table, and less acute inclines of the cusps, the crown can be kept away from

touching opposing cusps in excursive movements. Canine guidance can help here to

keep the premolar’s dimensions comparable to adjacent posterior teeth for acceptable aesthetics, yet protecting the implant crown from excursive forces (Fig. 15.1).

Multiple Unit Implants in the Aesthetic Zone

• Incisor-Incisor: light contacts on protrusive movements. Canine guidance is

favorable.

• Incisor-Canine: light contacts on protrusive movements, group function on laterotrusive movements with little or no contacts on canine.

• Incisor-Canine-Premolar: light contacts on protrusive movements, group function on laterotrusive movements with little or no contacts of restorations on the

implants.



15.5.5 Absence of Posterior Balancing Interferences

In cases where patients have posterior interferences, they may develop avoidance

patterns which involve moving the mandible forward, thus generating forces outside the pathways of normal function and transferring these unfavorable loads to



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R. G. Stevenson III and A. Agnihotry



the anterior teeth. In the natural dentition, we see the negative effects of this by

observable and accelerated wear and tooth chipping, tooth mobility, and diastema

creation [29]. With implant restorations, the negative effects will include screw

loosing, abutment fracture, restoration chipping or fracture, and even implant fracture [30]. As stated above, it is paramount for the posterior dentition to be in a

stable and comfortable physiologic state prior to planning anterior implant

restorations.



15.5.6 Absence of Muscle Disorders

Muscles get sore and painful, when overworked. Spasms in muscles from continued

nonfunctional use are often a sign found in cases of occlusal dysfunction, pathways

issues, and, of course, parafunction. For dysfunction and improper pathways of

function, the muscles are trying to accommodate the teeth, joints, and nervous system in a trifecta of harmony. Parafunction is different. It is important to note that

parafunction is a brain-mediated event and cannot be corrected by improving the

occlusal contacts of the dentition [31]. Muscle pain from bruxism is reported upon

awakening and is not curable perhaps but is entirely amenable to certain treatment

strategies. Simply prescribing an occlusal guard without understanding the underlying etiology is unwarranted and contraindicated. Sleep disorders have been reported

to correlate highly with the presence of sleep bruxism, and this requires a series of

diagnostic tests and evaluations to treat properly [32]. Patients should receive at a

very minimum an Epworth Sleepiness Scale questionnaire and an airway evaluation

prior to embarking on any oral rehabilitation [33]. If a sleep problem is suspected,

it is wise to refer to a specialist in this area of dentistry.



15.5.7 Absence of TMJ Disorders

Patients that complain of joint pain or who are incapable of taking loads on the

joints (via a joint load test). Temporomandibular issues must be resolved or at least

mitigated by the appropriate dental experts prior to significant oral rehabilitation.

Criteria for the diagnosis of occlusal dysesthesia (a contraindication of significant restorative treatment) [34]:

1 . Complaint of uncomfortable bite sensation.

2. Significant associated emotional distress.

3. TMJ symptoms lasting more than 6 months.

4. History of various bite-altering dental procedure failures.

5. Absence of dental occlusal discrepancies or the occlusal discrepancies present

are disproportional to the degree of the complaint.

6. The occlusal discrepancy is not attributed to another disorder (dental pathology,

muscle, temporomandibular joint, or neurologic disorder).



15  Implants in the Aesthetic Zone: Occlusal Considerations



305



15.6 Formulating a Functional Diagnosis

A straight forward approach to determine a functional diagnosis is to perform the

following tests:

1. Occlusal questionnaire

2. Joint load test/joint auscultation/joint palpation

3. Muscle palpation

4. Analysis of the dentition (wear, mobility, and excursive movements)

The above tests will allow the clinician to render the following diagnoses: acceptable function, dysfunction, pathway issues, parafunction, or some kind of TMD/

neuromuscular issue which will require a dedicated treatment approach outside of

the realm of typical restorative procedures.

Acceptable Function: With a diagnosis of acceptable function, the clinician

may proceed with treatment of the dentition without occlusal rehabilitation

because the system is working within the physiologic boundaries of the patient.

Care must be taken not to disrupt the stability of the individual’s occlusion in

these cases, or serious consequences may arise, which may require additional

treatment to resolve. The goals of occlusal therapy should always follow the preception that our restorations will maintain a stable occlusion, and in cases where

the occlusion is unstable or destructive, it will correct or improve the stability of

the occlusion. With acceptable function, the articulator is used to reproduce the

maxillo-mandibular relationships and incisal plane via an accurate face bow [21].

Hand-articulating the casts is generally sufficient to proceed with the case.

However, in the event that the OVD will be altered, the casts must be mounted

with a centric relation method (like a leaf gauge or deprogrammer) because the

MIP position will be altered (Table 15.3) [35].

Occlusal Dysfunction: With patient’s whose posterior teeth do not achieve a

stable/comfortable MIP, when interference-related posterior wear is noted or accelerated anterior wear exists, it may be possible to confirm the diagnosis with the use

of an occlusal deprogrammer. Muscle pain will be a frequent finding in these cases,

especially the lateral pterygoids [36]. The deprogrammer will ease the spasms of

the offending muscles and allow the mandible to move posteriorly on the anterior

bite plane. The patient should be completely comfortable while in this position

[37]. This usually occurs after 1–4  weeks with 20  h of daily use. Interocclusal

records are taken at this new position (CR), and casts are then mounted for analysis. It is often possible to paint the casts with paint (Tempera paint in a contrasting

color from the stone color) to track the adjustments made with a trial equilibration

made directly on the casts. This approach allows the clinician to evaluate the extent

of occlusal grinding necessary to achieve a stable occlusion. During trial equilibration, the anterior teeth should be left unaltered with the end point being that of

bilateral posterior contacts on cusps, fossae, and marginal ridges and not on inclines

which could produce deflective patterns, non-axial forces, and instability. It can be



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R. G. Stevenson III and A. Agnihotry



Table 15.3  Five possible occlusal diagnoses (Adapted from John Kois, DMD)

Diagnosis

Acceptable

function



Occlusal

dysfunction



Joint

symptoms

None—the

joint may

be loaded

without

discomfort



Muscle

symptoms

None—the

muscle of

mastication is

pain-free

when palpated



Joint may

be slightly

tender

when

loaded



Accelerated

anterior wear

with flat

incisal edges

or isolated of

unilateral

posterior wear

Sore muscles, Anterior wear

with the

especially

lingual of the

lateral

maxillary

pterygoids

anterior teeth

and the facials

of the

mandibular

anterior

Muscles may Wear on all of

or may not be the teeth,

especially

tender

posteriors

(with

bruxism) and

isolated wear

with habits

Muscles may Various

or may not be

tender, but

unusual

patterns exist,

including

myofascial

pain, etc.



Pathway issues Joints

usually

tender,

especially

when

patient

closes into

MIP

Parafunction



Joints may

or may not

be tender



Joints

TMD/

neuromuscular usually

painful

disorders



Muscles

usually sore,

especially

lateral

pterygoids



Wear patterns Further tests

Normal wear, None

or stable wear

from previous

conditions

(accelerated

wear not

active)



Treatment

Proceed

normally, but

be aware that

new

restorations

may generate

instability if not

adjusted

properly

Deprogrammer; Equilibration,

jaw finds CR in restorations, or

orthodontics

1–4 weeks



Deprogrammer;

jaw moves

forward on bite

plane



Orthodontics,

replace bulky

anterior

crowns, or open

VDO



Optional

deprogrammer

to evaluate wear

patterns on bite

plane



Treat with

orthotic and

restorations

designed for

heavy forces

and assumed

fractures



TMJ work-up

and definitive

diagnosis



Refer to OFP,

or treat with

extreme caution



further determined which teeth will require restorations due to hypo-occlusion

where onlays or crowns may be made to achieve occlusal contact or when extensive adjustments leave the tooth unprotected by enamel. The goal of occlusal equilibration is to spare the anterior teeth from further destruction, and equilibration

must be accomplished when indicated, prior to the initiation of aesthetic implant

restorations.



15  Implants in the Aesthetic Zone: Occlusal Considerations



307



Fig. 15.2  Typical MIP contact area (left), functional pathway (center), and pathway-­related

wear areas (right)



Pathway Issues (Constricted Envelope of Occlusion, Constructed Chewing

Pattern): Perhaps, one of the more poorly understood issues in field of occlusion is

the pathways taken by the anterior teeth during normal function. The mandibular

movements during chewing mimic a teardrop shape (see Fig. 15.2), where the teeth

come close but do not touch until MIP is established. When this natural pathway is

altered and the teeth touch during closure, the resultant friction leads to wear of the

occlusion tooth surfaces. In a constricted envelope the maxillary anterior teeth are

interfering with the normal closing pathway of the mandibular teeth. The facial

surfaces of the mandibular incisors and canines are wearing against the lingual

surfaces of the maxillary incisors and canines during sleep, phonation, chewing,

speaking, or swallowing. This wear pattern seems to occur during normal chewing

and often seen clinically when a patient with a class IV composite meeting the

requirements of an articulator-based occlusion returns soon after placement with a

failure of the restoration. The system is flawed—the patient cannot chew without

having the anterior teeth rub against another, which in turn leads to wear, flexing of

the teeth, mobility, diastema creation, or distalization of the mandible. Patients

with pathway issues may experience the inability to chew hard food; they may be

fast eaters (it is uncomfortable to eat) and experience TMJ pain, muscle pain, or

frequent problems with anterior restorations as described above. The anterior

deprogrammer is an excellent tool to confirm the diagnosis, as the patient will typically move forward on the anterior bite plane after treatment. The treatment solution for a pathway issue is to create more space for the anterior teeth to move in and

out of MIP without friction. This space may be established via several different

approaches: orthodontics (to expand the maxillary teeth or slightly retract the



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R. G. Stevenson III and A. Agnihotry



mandibular teeth); orthognathic surgery (to realign the maxilla and mandible to

better approximate the dentition), increasing the OVD; or occasionally the placement or replacement of anterior restorations which are either too bulky (maxillary

lingual surfaces of crowns are often the culprit), or the repositioning of teeth with

crowns (rarely indicated due to pulpal involvement). Pathway issues are not treatable with equilibration. Equilibration will decrease the OVD and exacerbate the

issue. It is critical that aesthetic zone implant restorations obey the laws of healthy

dynamic function, and NOT interfere with chewing, speech, swallowing, and

breathing (Fig. 15.2).

Parafunction: It is the broad definition given to nonfunctional activities that the

individual performs either consciously or unconsciously. Often these occur during

the day, via clenching, rubbing the surfaces in eccentric patterns and border movements, protruding the mandible and retracting it against the upper teeth, sliding the

anterior teeth against each other, and sleep bruxism (associated with breathing

issues or not). It is important that adequate guidance be established in order to at

least partially protect the teeth from accelerated destruction due to parafunction.

Restorations and equilibrations will not cure parafunction, as it is brain mediated,

but action should be taken to prevent parafunction activities from destroying restorations and teeth. Parafunction is multifactorial, and it is good to understand the

neurological pathways involved and the patterns of jaw movements that occur under

different conditions including nocturnal (sleep bruxism and sleep disordered

breathing-­

related wear) and diurnal conditions (clenching, habits with foreign

objects, finger nail biting, and other conscious/subconscious habits). Thoughtlessly

prescribing a “night guard” is a poor service for the treatment of a disease with a

varied but specific etiology. It shows a complete lack of a definitive diagnosis and is

potentially dangerous, especially with an untreated sleep disorder. The use of night

guards to treat true sleep bruxism (which only occurs in 9.7–15.9% of patients) [38]

is appropriate assuming that a sleep breathing disorder is not the primary issue.

Using “day guards” to treat habitual clenching is also indicated when this is indeed

the issue; however, some individuals cannot tolerate wearing appliance during the

day. Nonetheless, after completing a rehabilitation with ceramics (particularly thin

or fragile restorations), the use of a night guard (constructed of a soft intaglio and a

hard shell) as an insurance policy against an episodic or aberrant nocturnal parafunction is recommended [39]. At the restoration delivery appointment, the clinician should perform a “crossover check,” as described in the following section

(Table 15.4).



15.7 C

 linical Techniques for Occlusal Adjustments During

Implant Restoration Delivery

Restoration Cementation/Screw Tightening and Access Closure: These techniques have been covered in Chap. 14 and should be followed precisely, as significant research and much clinical trial and error have gone into the approaches

described.



309



15  Implants in the Aesthetic Zone: Occlusal Considerations

Table 15.4  The five-step occlusal check

Step

Name of

check

Jaw

movement



1

MIP



Posterior

contacts



Even, bilateral

posterior

contacts (cusp

tips, marginal

ridges, and

fossae)



Anterior

contacts



Close teeth

together



2

Lateral

excursives

Move jaw left

and right



No contacts on

posterior teeth

unless group

function is

designed to

lessen load on

canine implant

Anterior teeth No contacts in

touch lightly in anterior teeth

MIP



Implant

restoration

contacts



Implant

restorations

only touch

when patient

squeezes teeth

together



Articulating

paper used



8–12 μm

BLUE paper



3

Protrusive



4

Crossover



5

Chew test



Move jaw

forward



Position teeth

edge to edge,

and move

side to side

No contacts

on posterior

teeth



Chew on wax

for 30 s, then

insert paper,

and chew 30 s

No contacts

on posterior

inclines in

group function

design



No contacts

on posterior

teeth



Even bilateral Even,

smooth

anterior

dis-occlusion surfaces, no

catches,

broad

contact areas

Light

No contacts on No contacts

contacts,

anterior implant on anterior

smooth

implant

restorations if

restorations if surfaces, no

possible

catches,

possible

broad

contact areas

8–12 μm RED

8–12 μm

8–12 μm

paper

RED paper

RED paper



No contacts

on anterior

teeth with

200 μm paper

No contacts

on anterior

implant

restorations

with 200 μm

paper

200 μm paper



The Five-Step Occlusion Check: This system has been developed to respect all

aspects of occlusal theory and provides a practical, repeatable, and reliable method

of insuring predictable results with implant-retained restorations. It has been shown

to provide restorations that are comfortable, more durable, and more successful.

During the following steps, the implant restoration is firmly seated and cemented or

screwed into place, and in the case of a screw access, the final composite cover has

been placed (Table 15.4).

1. MIP Check: With the patient seated upright, thin (8 or 12 μm, Arti-Fol (Bausch) or

Troll Foil (Troll Dental)) articulating paper is positioned between the teeth, and the

patient is instructed to close several times, tapping on their posterior teeth. Contacts

are recorded and analyzed, and the only anterior contact should be the distal of the

maxillary canine. The maxillary incisor lingual surfaces should be free of contacts

at this stage. Then, shim stock is placed between the anterior teeth and the patient

instructed to squeeze. With the teeth held together tightly, the shim stock should be

held by the anterior teeth; however, when the patient bites with normal force, the

shim stock releases. Contacts are then analyzed for their size. The paper is reinserted, the teeth squeezed together, and the contacts analyzed. The contact sizes



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