Practical Occlusion

Lecture from 8/21/2025

what is healthy occlusion?

when the muscles and joints of the jaw and teeth work together in harmony

what are the 5 key components that affect occlusion?

joints, muscles, periodontium, teeth, airways

occlusal trauma

injury resulting in tissue changes within the attachment apparatus (including PDL, supporting alveolar bone, and cementum) as a result of occlusal force

in teeth with progressive/severe periodontal disease, trauma from occlusion may…

enhance the rate of progression of the disease (aka act as a co-factor in the destructive process)

what are the signs of healthy periodontium?

1-3mm pockets

no bleeding

healthy gingiva

adequate bone level

good bone architecture

adequate crown to root ratio

what are signs of periodontal disease?

>4mm pockets

bleeding

inflammed gingiva / gingival recession

bone loss

mobility

poor crown to root ratio

fremitus

primary occlusal trauma

excessive occlusal forces are applied to a periodontium with normal bone support and normal attachment levels

what are examples of primary occlusal trauma?

bruxism, malocclusion, high restoration

secondary occlusal trauma

normal or excessive occlusal forces act on a periodontium that has already been compromised by bone loss due to periodontitis

what does secondary occlusal trauma occur in the presence of?

bone loss, attachment loss, normal or excessive occlusal forces

what are clinical indicators of occlusal trauma?

mobility (progressive), fremitus, occlusal interferences, wear facets in presence of other clinical indicators, tooth migration, fracture tooth/teeth, thermal sensitivity

fremitus

vibration on teeth 6-10 when a patient bites down, indicates occlusal trauma

what are radiographic indicators of occlusal trauma?

widened PDL space, bone loss (furcation, vertical, circumferential), root resorption/fracture, hypercementosis, thickened lamina dura, cemental tear

what happens under slight tension?

apposition of bone, PDL fibers elongate, blood vessels enlarge

waht happens under greater tension?

widened PDL, tearing of the ligament, hemorrhage, thombosis, bone resorption

what happens under slight pressure?

bone resorption, widened PDL, numerous blood vessels are reduced in size

what happens under greater pressure?

compression of fibers, vascular changes, injury to fibroblasts and CT cells which leads to necrosis of ligament, increased bone/tooth resorption

reparative activity includes the formation of…

new CT cells/fibers, bone and cementum

thinned bone is reinforced with new bone

repair occurs as long as…

reparative capacity exceeds traumatic force

adaptive remodeling

forces exceed repair capacity, periodontium is remodeled, with remodeling forces may no longer be injurious to the tissues

what are the results of adaptive remodeling?

widened PDL, funneling at the crest of bone and angular defects, no pocket formation, tooth mobility

what is the treatment for primary occlusal trauma?

reduce/eliminate tooth mobility, eliminate occlusal pre-maturities (fremitus), eliminate parafunctional habits, prevent further tooth migration, decrease/stabilize radiographic changes

what is the treatment for secondary occlusal trauma?

temporary/provisional/long term stabilization of mobile teeth with removable or fixed appliances, occlusal adjustment, management of parafunctional habits, orthodontic tooth movement, occlusal guard, occlusal reconstruction

what is the biggest difference between an implant and a natural tooth?

PDL

what are the occlusal schemes for a single implant or an implant supported partial denture?

mutually protected occlusion with anterior guidance or evenly distributed contacts with wide freedom in centric relation

what causes increased occlusal overload when a patient has an implant?

large cantilever, parafunction habits, steep cusp inclines, poor distribution of forces (limited contact interferences), poor bone quality

what are clincal presentations of an increased occlusal overload when a patient has an implant?

screw loosening, prosthesis failure, screw fracture, implant fixture fracture, implant failure

what are the major causes of biomechanical complications for a patient with an implant?

overloading the implant aggrevates plaque induced bone resorption in presence of peri-implant inflammation

occlusal overloading can be positively associated with perimplant marginal bone loss

how can we prevent increased occlusal overload for a patient with an implant?

reducing cantilevers (increasing number of implants), increased number of contact points, monitoring parafunctional habits that narrow the occlusal table, decrease cuspal inclines, use progressive loading in patients with poor bone quality

where should you see contacts on teeth opposing an implant?

only the central fossa

implants do not have PDL so they should not be involved in any lateral forces

what are signs of occulsal disease?

tooth loss, erosion, bruxism, change in VDO, change in overbite and overjet, change in tooth position, change of the occlusal plane

vertical dimension of occlusion

the distance between 2 selected anatomic or marked points (usually one on the tip of the nose and the other on the chin) when in maximal intercuspal position (MIP)

what are signs of a loss of VDO?

reduced inter-arch distance when teeth are in occlusion, fatigue when chewing, loss of space for restorations/prostheses, loss of facial dimension, facial distortion, deepening of the nasolabial fold, increased risk for angular cheilitis, lower face appears collapsed

*t/f decreasing or increasing vertical dimension can happen unilaterally

false- needs to happen bilaterally and during a one time restorative procedure like a complete denture, full arch reconstruction, or a combination of fixed and removable prosthodontics

deep overbites are almost always related to…

strong lip pressures and a tight neutral zone

how can you improve an anterior deep overbite?

reshaping or shorten maxillary teeth (intrusion, enameloplasty, crowns), shortening lower incisal edges in combination with restoring holding contacts, stable posterior occlusion, increase VDO, reposition incisal edge (ortho, intrustion), shorten mandibular teeth (crown lengthening, RCT, extraction and implants)

phonetically, esthetically, and fuctionally, why is the anterior occlusal plane important?

phonetics: F and S sound

esthetics: tooth proportion, gingival line, smile line- interpupilary line

function: amount of guidance

anatomically and esthetically, why is the posterior occlusal plane important?

anatomically: alas trigs line and retromolar pad, lateral border of the tongue

esthetics: smile line, curve of spee, and curve of wilson

what happens during the diagnostic phase of treating an incorrect/traumatic occlusal plane?

preliminary impressions, facebow, CR record with LG and study cast mounted on semi-adjustable articulator

what is the purpose of a diagnostic wax-up when treating an incorrect/traumatic occlusal plane?

restore normal tooth morphology, tentative determination of VDO, re-establish occlusal plane, restore centric, canine, and incisal guidance