11 - Occlusion Flashcards
Describe different theories on the spread of inflammation
• Inflammation is related to the anastomoses between the oral gingival epithelium and the interalveolar arteries, coursing into the bone marrow on the periosteal side of the alveolar bone without penetrating the PDL.
• Inflammation follows the course of the blood vessels into alveolar bone marrow spaces. The spread to PDL is secondary. Defect morphology depends on location of blood vessels and thickness of bone as a result of inflammation
• Weinmann 1941
• When rubber dams were placed between rat molars, the occlusal trauma itself did not cause periodontitis but altered the pathway of inflammation down the PDL.
• Normally, inflammation followed the blood vessels
• Have pressure and tension zones.
Macapanpan 1954
Describe Glickman’s 2 zones
• The Zone of Irritation is bound by gingival fibers that is affected by local irritants and unaffected by occlusal forces
• The Zone of Co-Destruction is the PDL/bone/cementum/transeptal fibers/alveolar crest fibers. With normal occlusal load, inflammation moves along fiber bundles into bone. With excessive occlusal forces, the fibers are altered and inflammation spreads into the PDL to create craters and intrabony defects
○ Therefore, occlusal trauma + inflammation can cause destruction of supporting tissues
Transseptal fibers are the dividing line
Describe buttressing bone
• Buttressing bone is observed in areas opposite of resorbing areas to reinforce the trabeculae by compensating for lost bone from occlusal forces that are not severe enough to produce trauma from occlusion.
• More severe occlusal trauma may result in angular or dehiscence defects
• Studied in rhesus monkeys
Glickman 1965
What happens to nonfunctional teeth
• In a monkey study, nonfunctional teeth had:
○ Increased plaque/calculus/gingivitis
○ Supraeruption
○ Narrower PDL at midpoint
○ Atrophy and loss of functional orientation of fiber bundles
Pihlstrom 1971
What are the conclusions of the American and Scandinavian occlusion studies?
§ Healthy periodontium + TOF à increased mobility, widened PDL, and loss of crestal bone height and volume (physiologic adaptation). NO CAL
§ Presence of tooth mobility does not increase rate of periodontitis
§ ChP + TOF à occlusal trauma MAY increase the loss of CT and bone (YES dog, NO monkey, humans unknown)
Removal of TOF w/o resolution of ChP does not allow healing
Describe the sphere of influence
• It describes the relationship of the distance from plaque to bone (0.5-2.7mm, 1.63mm) and the distance from plaque to CT attachment (0.2-1.8mm, 0.96mm)
• The loss of attachment is related to subgingival plaque and there is no association between angular defects and traumatic occlusal forces
Waerhaug 1979
Are non-working contacts related to periodontal disease?
• In a retrospective review of charts/casts/radiographs, there was a SS increase in mobility, bone loss, and PD in teeth with a nonworking contacts
• 53% of molars had nonworking contacts
• This supports Glickman
• However, these patients had significant disease
Youdelis & Mann 1965 (Washington)
How are occlusal relations and periodontal status related?
• In a study of exams completed on patients, the findings were:
§ 78% CR-CO shift
§ 56% NW contact (2nd molars)
§ Bilateral group function most common
• NO relationship between NW contacts and periodontal status
• However, these were young patients with minimal disease
• Shefter & McFall 1984
• In a Chinese population, it was found there was no relationship between NW contacts and PD/CAL/RBL
• Teeth with mobility and fremitus had greater PD/CAL/bone loss. This promotes the idea of occlusal adjustment as necessary
• Trauma from Occlusion Index (TOI) à functional mobility and widened PDL
• Adaptability Index à pronounced tooth wear and thickened lamina dura
• Jin & Cao 1992
• In the largest cross-sectional study (SHIP) with occlusal and periodontal exams, 39% had non-working contacts. After adjusting for factors (age, male, smoking, education) non-working contacts were associated w/ PD and CAL
• Tilted teeth significantly associated with PD and CAL
• The magnitude of effect was increased PD by 0.13mm and CAL by 0.14mm. Small magnitude of effect.
Bernhardt 2006
Are occlusal adjustments warranted?
• In a group of ChP patients with SRP + occlusal adjustment, surgical treatment, and periodontal maintenance, the occlusal adjustment group had a 0.4mm greater improvement in CAL at 2 years compared to the group w/o occlusal adjustment.
• There was no difference in occlusal adjustment for PD reduction and initial tooth mobility did not affect clinical attachment response to occlusal adjustment
Burgett 1992
What are indications for an occlusal adjustment?
• Increasing fremitus/mobility • Discomfort during function • Parafunctional habits • Soft tissue injury • Food impaction • In conjunction w/ orthodontic therapy or orthognathic surgery Traumatic injuries
What is the etiology of abfraction?
• NCCL strongly coincided with occlusal irregularities
§ Wear facets 95%
§ Lack of canine disclusion 77%
§ Group function 73%
• NCCL found 30% supra, 30% sub, 30% juxta-gingival
Miller 2003
How does tooth mobility relate to response to periodontal therapy?
• In an 8-year Michigan longitudinal study with baseline occlusal adjustment/SRP, teeth with:
§ Mobility 1 successfully treated and maintained w/ no further CAL
§ Mobility 2 no CAL gain
§ Mobility 3 CAL loss
• Firm teeth respond better than loose teeth
• Fleszar 1980
In a beagle dog study with jiggling forces and good hygiene, mobility does not affect marginal gingiva or inflammation but may decrease resistance to probing due to decreased collagen and increased vascularity of the supracrestal CT attachment
Does mobility affect GTR results?
• 55 patients had GTR + membrane and examined effect of tooth mobility (PerioTest) on CAL gain
• Mobility negatively affected CAL gain, with more mobility at baseline leading to smaller CAL gain at 1 year (P=0.036). May benefit from reducing mobility in teeth treated via regeneration
• Cortellini 2001
• Teeth with Miller 1/2 with 2/3 wall intrabony defects respond similarly well to GTR
• Excluded teeth that needed splinting
Trejo & Weltman 2004
What are indications for splinting?
• Mobility interferes w/ patient comfort or function • Prevent tipping of drifting of teeth • Prevent extrusion of unopposed teeth • Following orthodontic therapy • Following acute trauma to teeth Esthetic and prosthetic demands
Provide evidence for why splinting is effective.
• Unsplinted maximal bite force with reduced bone support 357N and 378N for periodontally healthy patients
• In splinted posterior teeth, the maximal bite forced increased to 509 and 534N
• Kleinfelder & Ludwig 2002
• A group of patient’s treated with Coral calcium BRG and with either pre-splint, post GTR splint, or non-splint
• Splinting teeth prior to surgery w/ GTR resulted in better clinical improvement compared to post-surgery splinting or non-splinting
Schulz 2000
