What are the features of normal PDL and occlusal forces?
dense collagen fibers attached to bone & cementum w/minimal vascularity
What happens after increased vascularity from traumatic occlusion?
stimulation of osteoclasts -> bone loss and widened PDL-> mobility
then: loss of density of collagen and functional fiber arrangement
What is primary and secondary occlusal trauma?
Primary: PDL changes in normal peridontium affected by increased occlusal loading from bruxing, clenching or high restoration
secondary: teeth w bone loss from perio disease and traumatic occlusion
What are radiographic features of traumatic occlusion?
widened PDL, thickened lamina dura
bone loss in furcation (confirm clinically by probing)
increased fremitus, mobility
What is a buttressing bone?
large hyperplastic bone response to heavy occlusal load
outer alveolar surface
Is gingival recession caused by traumatic occlusion?
no, related to inadequate keratinized gingiva and excessive toothbrushing\
What are most cervical tooth lesions from overzealous brushing shaped?
wedge 50%, round 22%, mixed 28%
abfraction not clinically reproducable
What are the 3 factors of consideration for structurally compromised teeth?
What is the Ferrule effect?
Crown must encircle a color of sound tooth structure
Maintains transfer of functional forces to root/PDL/alveolar bone
Need minimum of 1.5-2mm on facial and lingual
What are the factors to consider for crown lengthening?
Esthetics: harmony of tissue heights
Support: root length in bone
Adjacent teeth: iatorogenic perio defects?
What are the indications for crown lengthening?
Adequate crown preparation: gingival margins must not invade biological width requirements for periodontal health
What are the biological width requirements?
Minimum of 1mm between apical level of the junctional epithelium and bone crest
Width of junctional epithelium + CT width = biological width
Where does a perio probe stop?
Apical portion of junctional epithelium
What is the method of choice for crown margins that violate the biological width?
Flap surgery with osseous resection
What is the distance needed between the level of the crown margin and the crest of bone?
A flap must go beyond _____ otherwise tissue will go back to original position.
Flap surger requires how much crestal bone exposure?
At least 3mm
What are the indications for gingivectomy?
adequate band of Keratinized tissue and bone crest is positioned apically with an initial wide Biological Width
How long post gingivectomy until final restorations(subgingival) should be placed?
6 weeks after surgery
12 weeks in esthetic areas to ensure no further gingival recession
What are the indications for subgingival margins?
INDICATIONS FOR SUBGINGIVAL MARGINS
1) ESTHETICS. For restorations in the esthetic zone.
2) RETENTION. There is a need for increasing the available volume of the restoration.
3) CARIES, FRACTURES or previous restoration is already extended subgingivally.
4) Patients with high caries activity. Extension to subgingival region reduces risk of recurrent caries around margin.
What is the problem with cement filled margins?
Eventually dissolve and leak
How big is the average marginal gap?
80-95 microns in anteriors
90-145 microns in posteriors
What is the advantages of composite restorations?
Bonding to enamel and dentin therefore have minimal (10 microns) margins
Where should subgingival margins be placed?
MIDDLE OF THE DEPTH OF THE GINGIVAL SULCUS
1 TO 1 1/2mm BELOW THE MARGINAL GINGIVA IN HEALTHY PATIENTS.
THIS WILL PLACE THE MARGIN OPPOSITE THE THICK EPITHELIAL LAYER OF THE ORAL SULCULAR EPITHELIUM AND AVOID CONTACT WITH THE MUCH THINNER JUNCTIONAL EPITHELIUM WHICH IS IN THE APICAL PART OF THE GINGIVAL SULCUS.
What technique helps reduce incidence of perio disease with implants?
Platform switching: place narrower diameter abutment to move argin away from direct contact with bone
Why must removal of implant provisional and seating final crown be done immediately?
TENDENCY FOR GINGIVAL TISSUES TO COLLAPSE OVER THE IMPLANT
RESULT IN COMPRESSION OF THE GINGIVAL TISSUES AND BLANCHING.
Where is the bulge in natural teeth?
Point: do not overcontour teeth thinking it will protect gingiva
Or have flat contour in gingival 3rd
How do big interproximal restorations affect gingiva?
COMPRESS THE INTERDENTAL PAPILLAE AND PREDISPOSE THE REGION TO PERIODONTAL INFLAMMATION. CROWDED EMBRASURES ARE ALSO MORE DIFFICULT FOR THE PATIENT TO ACCESS FOR ORAL HYGIENE PLAQUE REMOVAL
What are the guidelines for restorations to ensure gingival health?
SHOULD NOT HAVE CONTOURED AREAS THAT EXTEND APICALLY MORE THAN 2 mm. APICAL EXTENSION
BEYOND THIS CAUSES A SPLIT BETWEEN THE FACIAL AND LINGUAL PAPILLA WITH RESULTING COMPROMISE OF THE EPITHELIAL SEAL AGAINST THE TOOTH AND PLAQUE THEN CAUSES INFLAMMATION, POCKET DEPTH AND BONE LOSS .
How do open contacts affect gingiva?
PREDISPOSE TO PERIODONTAL POCKETS AND BONE LOSS DUE TO ENHANCED PLAQUE ACCUMULATION AND DIRECT TRAUMA TO THE PAPILLA FROM FOOD IMPACTION.