What is a local factor that increases plaque biofilm retention?
Rough edge on a restoration harbors plaque biofim and makes it difficult to remove w/ a brush and floss
What is a local factor that increases plaque biofilm pathogenicity?
Calculus deposits harbor plaque biofilm, allowing the biofilm community to grow uninhibited for an extended period
What are some local factors that can inflict damage to the periodontium?
- Ill-fitting dental appliance that puts excessive pressure on the gingiva
- History of traumatic toothbrushing
- Trauma from occlusion
- High frenal attachment
Characteristics of calculus
- Mineralization of plaque 48 hours to 2 weeks after biofilm formation
- Irregular porous surface for bacterial biofilm retention
- Fixed source for plauqe accumulation proximal to the tissue leads to gingival inflammation
- Difficult to contro gingivitis or perio in presence of deposits
What is the composition of calculus?
70-90% inorganic-> Calcium phosphate, calcium carbonate, magnesium phosphate
Organic-> Plaque biofilm, dead epithelial cells, dead WBCs and living bacteria
What ar ethe 3 types of calculus?
“Brushite”- Crystaline, newly formed
Crystalline octacalcium phosphate- < 6mos
Crystalline hydroxyapatite- > 6mos
Modes of calculus attachment
- By pellicle- on enamel surfaces, easily removed
- By irregularities in tooth surface- Cracks, openings where PDL fibers were attached, grooves from instrumentation etc
- By direct contact of calcified component and tooth surface- matrix of calculus interlocked w/ inorganic crystals of the tooth
What is biologic width?
The zone of soft tissue occupied by the JE and the CT fibers immediately apical to the JE
Portion of the periodontium coronal to the alveolar crest
* Gingival sulcus- 0.69mm
* JE- 0.97mm
* CT attachment- 1.07mm
=2.04mm (~3mm incl. sulcus)
When does violation of biologic width occur?
If restoration margins encroach on this zone
What does this picture depict?
Acute invasion
What does this picture depict?
Chronic invasion
What is occlusal trauma?
Direct damage to the periodontium from excesive biting forces on teeth
AB resorption can result from increased pressure
Can be more rapid destruction by preexisting perio
Clinical signs of occlusal trauma
- Tooth mobility
- Sensitivity to pressure
- Migration of teeth
Radiographic signs of occlusal trauma
- Widened, funnel-shaped PDL
- Angular alveolar bone resorption
What is primary occlusal trauma?
- Excessive occlusal forces on an intact periodontium w/ no previous history of periodontal breakdown
- Widened PDL
- Tooth mobility
- Tooth/jaw pain
- Reversible when traua is removed
- Trauma may be expressed as wear to teeth rather than mobility
What is secondary occlusal trauma?
Normal (or excessive) forces on a periodontium compromised by perio
Inflammation+OT= rapid bone loss
Additional damage to periodontium can occur due to lateral forces on teeth w/ attachment loss
WHat are functional occlusal forces?
Normal chewing forces
What are parafunctional habits?
Tooth-tooth cvontacts outside of eating:
* Clenching
* Grinding/bruxing
* May be conscious or unconscious, or nocturnal
* Therapy: Selective occlusal adjustement and/or occlusal appliance fabrication
What is abfraction?
The pathological loss of tooth substance caused by biomechanical loading forces that result in flexure and failure of enamel and dentin at a location away from the loading
