DHYG 210: Occlusal Exam

Tues, Sept 23rd 2025

What is Dental Occlusion

The relationship that occurs when the maxillary and mandibular teeth come together in functional contact

4 Aspects to an Occlusal Examination

1. The morphology of the dentition 

2. Physiological state of the dentition 

3. The dentition and the temporomandibular articulation 

4. Habitual patterns of dental contact

Describe the two ways we measure physiological integrity

• Structural integrity 

  • Evaluated by examining the teeth for excessive or premature wear 

  • Ex. cracking of enamel, fractured cusps, and failing restorations are some of the signs 

• Mobility (structure of teeth, etc)

  • Another cardinal test of physiological integrity 

  • Doesnt signify perio disease, but may indicate excessive occlusal loading

Describe the structure and function of the TMJ Articulation

• Structure 

  • Composed of condyle in a fossa with a disc interposed between two bony surfaces 

  • The TMJ is lubricated 

• Function 

  • Functions with a degree of rotation followed by translation down the eminence as jaw opens (the jaw first rotates and then slides)

  • Teeth alignment 

    • Intercuspal tooth position needs to be stable to allow for proper joint function 

    • Tooth guidance needs to be in harmony with jaw function 

  • Pathology (problem w/ TMJ) can include: disc malposition, myalgias (muscle pain) and intra-articular joint inflammation

Describe the 4 components of the TMJ examination

1. Palpation - assessment of tenderness bc it is a possible signs of inflammation; assess intra-meatally and by lateral pole 

2. Joint sounds - ideally checked w/ stethoscope, and you need to distinguish between click, pop, crack or crepitus; also check for timing 

3. Range of motion - objective measure; inter-incisal distance; measure if client experiences pain or no pain; vertically and laterally; f-35 and m-40, laterally 8mm

4. Jaw trajectory - mandibular deviations from midline on opening and closing (if jaw moves off center instead of up and down)

Describe what the Intercuspal Position is

It is where the teeth have the most contact and your jaw is in a comfortable, stable position

“the best fit” of your teeth when you bite down

What is an Acquired but “Functional” Intercuspations

When the teeth doesn’t line up in a “perfect/normal” way, but the person has adapted to it and the bite still functions normally

What is an Ideal Static Occlusal Contact?

When the upper and bottom teeth hits where its supposed to hit

What does the Actual Maxillary Occlusal Contact look like in a Normal Adult?

• The ideal is 34 contacts, but the average in a healthy young adult is 14 contacts 

• Most of us function quite well without meeting the ideal number of contacts

What are the most important aspects of an occlusal examination?

• It is the inspection of tooth wear patterns 

• While some patterns of wear are due to malocclusion, others are simply the consequences of a habit (ex. Being an oboe player would change your teeth into a circular shape?)

What do mild and moderate occlusal wear depend on?

Whether considered mild or moderate, wear depends on age and social circumstances of an individual

What are the mechanisms of Non Carious Cervical Lesions? (damage at the cervical not caused by caries)

• Endogenous (attrition) 

  • damage from forces inside the mouth

    • Normal occlusal function - such as chewing and deglutition (swallowing)

    • Parafunction - harmful habits such as bruxism and clenching

• Exogenous (abrasion/friction)

  • damage from outside forces or habits

    • Abrasion by overzealous brushing, flossing, tooth pick use 

    • Habits - nail biting and pen chewing

    • Occupational behaviours - sewing, playing instruments 

    • Oral appliances - orthodontic, or prosthodontic (crowns, dentures, implants)

    • Ritual behaviours, ethnic practises

What is the theory of the Abfraction?

• A proposed explanation for NCCL 

• The idea suggests that the loss of cervical tooth structure is due to flexural forces (blending stresses) rather than caries

• The forces come from repeated (cyclic) non-axial loads, meaning pressure that isn't straight up and down but grinding or off-centered biting

What is Bio-corrosion and what are their 3 different causes

• Bio-corrosion: chemical or enzymatic breakdown of teeth (from inside or outside), leading to enamel and dentin loss - “melting” of tooth structure 

• Three different causes: 

  1. Endogenous: bacterial acid degradation and acid reflux or bulimia - non metallic corrosion

  2. Exogenous: (chemical acids) such as lozenges, carbonated drinks, fruits

  3. Proteolytic corrodents: enzymatic breakdown of teeth, such as enzymes in caries, protease from pancreas, and pepsin from stomach

What are the multifactorial causes of wear?

• Attrition due to normal function and parafunction 

• Abrasion and erosion due to environmental influences 

• Bio-corrosion or chemical erosion due to specific types of food, bulimia, or stomach reflux 

• Loss of tooth structure due to physical means and/or habits

What is the purpose of an Occlusal Examination Protocol?

• To visually assess the dentition so you can document the gross form of the occlusion (such as tooth position, arrangement, and contact pattern) 

• Record occlusal contacts between maxillary and mandibular teeth  

• Determine molar classification

• Document and record areas and degree of tooth wear

• Visually assess dynamic tooth contact patterns (ex. Canine rise vs group function)

What is Overjet and Overbite and how are they measured?

• A measure of vertical and horizontal overlap 

• Overbite

  • how much the upper central incisor overlaps the lower central incisors 

  • measured in %

• Overjet

  • the distance between the lingual surface of the upper central incisor to buccal surface of the lower central incisors 

  • measured in mm

What is an Openbite Malocclusion

• When the anterior teeth do not touch when the mouth is closed, usually only the 2nd molars are the only occlusal contact points

• Why it happens:

  • Tongue thrust habit 

  • Possible thumb sucking habit as toddler

  • Orthodontic relapse

Anterior Crossbite

when a single or multiple anterior teeth sits behind the lower teeth

Posterior Crossbite

when the upper premolar/molar sits behind the lower teeth

Class I

• defined by a normal molar and canine relationship

  • where mesiobuccal cusp of upper 1st molar is located over mesiobuccal groove of lower molar 

Class II

• where the jaw is retrognathic

  • Malocclusion

  • Skeletally and Dentally retrognathic ( overbite)

  • First molar relationship more distal; upper canine is more forward than lower

Deep Class II Malocclusion

Characterized by an upright upper and lower anterior and an increased overjet and overbite

Class III

• it is prognathic 

  • A malocclusion 

  • Skeletally and Dentally pronathic ( underbite) 

  • the lower 1st molar is in front of the upper 1st molar; lower canine is also infront of upper

Class III malocclusion

• Multiple crossbites

• when the lower canine-lateral-central sits in front of the upper

What are the two latero-protrusive jaw movements? (how the tooth move side by side)

Group function - multiple posterior teeth sharing the load during lateral movements, can lead to wear and TMJ stress

Canine rise - only the canines contact during lateral movements

What are Protrusive Movements?

when the mandible moves forward from the normal bite position - guided by the anterior teeth and also protects the posterior teeth from wear 

What is Bruxism and the two types?

Diurnal or nocturnal parafunction affecting up to 20% of the population 

Two types: awake bruxism and sleep bruxism

What is Awake Bruxism

Tooth clenching and/or jaw bracing triggered by mental concentration, emotional stress, and/or anxiety - people with this are usually aware of their habits

What is Sleep Bruxism (SB)

Unconscious tooth grinding and clenching - affects about 8% of the population, can be mild, moderate or severe

Moderate to Severe SB is consider a sleep disordering when following criteria are met:

1.  Frequent grinding noises at least 5x per week confirmed by a sleeping partner 

2. Non-masticatory tooth wear in at least one sextant with (not from chewing food, but from bruxism):

   1. enamel reduction 

   2. dentin with loss of crown 

   3. Masseter muscle hypertrophy of 2-3 times the normal muscle volume during contraction

What is Abnormal Repetitive Movement Disorder and what are their two overlapping types?

• Jaw clenching and tooth gnashing or grinding

• Two overlapping types: awake (AB) or sleep bruxism (SB)

How is a Repetitive Jaw-Muscle activity characterized by?

Clenching or grinding of teeth and/or bracing or thrusting of the mandible

Night-bruxer (Adult) - what are their characteristics?

• Someone with long history of parafunction

• Occlusal and cervical wear in both arches

• Hypertrophic masseters commonly 

• Complaints of sensitivity being on and off 

• Restorative and esthetic needs due to breakdown

What is Lower Anterior Wear

Severe wear due to parafunctional habit, nighttime bruxism, and worsens with opposing metal ceramic crowns