Biologic width

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BIOLOGIC WIDTH

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 For Restorations to survive long
term…. PERIODONTIUM MUST
BE HEALTHY
 Periodontium to remain healthy
…RESTORATIONS MUST BE IN
HARMONY WITH
SURROUNDING TISSUES.

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MARGINS OF RESTORATIONS
 SUPRAGINGIVAL MARGIN
 EQUIGINGIVAL MARGIN
 SUBGINGIVAL MARGINS

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SUPRAGINGIVAL
MARGIN
 It has the least impact on the periodontium.
 Used in unaesthetic areas
 More translucent restorative material- now able to place
supragingival margin to esthetic areas

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EQUIGINGIVAL
 Retains more plaque

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SUBGINGIVAL
MARGIN
 Not accessible for finishing procedures
 If placed too below the gingival tissue crest
 Impinge on the gingival attachment apparatus
 Constant inflammation is created

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What will happen???????
 Body attempts to recreate room between
the alveolar bone and the margin to allow
space for tissue reattachment.

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What is biologic width????
 Biologic width is defined as the
dimension of healthy gingival tissue
which is attached to tooth coronal to
crest of alveolar bone.

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 Connective tissue occupies 1.07mm of space above
the crest of alveolar bone
 Junctional epithelium below the base of gingival
sulcus occupies 0.97mm of space above the
connective tissue attachment.
 Combination of these measurements gives biologic
width
 Apprx… 2mm

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When this is important?????
 At times restorations need to be extended gingivally
 To create adequate resistance and retentive form in the
preparation
 To make significant contour alteration due to caries or other
tooth deficiencies
 To mask tooth /restoration interface by locating it subgingivally

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If biologic width is violated what
happens????
 2 different tissue responses
 First response
 If alveolar bone is thin ,bone loss in unpredictable manner
 If the gingiva is thin and highly scalloped , recession occurs.
 This occurs to recreate room between alveolar bone and the margin to allow
space for tissue reattachment
 .Chronic inflammation of tissues can occur if gingiva is thick and fibrotic.
Sequel of biologic width
violation
• Chronic pain
• Inflammation of
gingiva
• BOP
• Gingival recession

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 Second response
 If gingiva is thick gingival inflammation develops and persists

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BIOLOGIC WIDTH EVALUATION
 CLINICALLY
 If patient experiences tissue discomfort when restoration margin
levels are assessed with periodontal probe ….. Biological width
violation….
 Clinical features: gingival inflammation around the restoration,
bleeding on probing, gingival recession, pocket formation, bone
loss.

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 BONE SOUNDING….probe to bone level and subtract sulcus
depth from resulting measurement .
 Probe is pushed through anesthetised attachment tissues from
the sulcus to underlying bone.
 If distance is less than 2mm at one or more locations biologic
width violation is confirmed.

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 RADIOGRAPHS
 Identify interproximal violations of biological width.
 NEW TECHNIQUE
 PARALLEL PROFILE RADIOGRAPHIC TECHNIQUE –used to
determine dimensions of dentogingival unit.

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CATEGORIES OF BIOLOGIC WIDTH
 NORMAL CREST
 HIGH CREST
 LOW CREST

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NORMAL CREST
Midfacial measurement is 3mm
Proximal measurement is 3-4.5mm
Seen in 85% of cases
Crown margin placed 0.5mm subgingivally is tolerated by periodontium

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HIGH CREST
 Usually seen in proximal surface adjacent to an edentulous site
 Midfacial measurement is <3mm
 Proximal measurement is less than 3mm
 Seen in 2% of cases

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LOW CREST
 Midfacial measurement >3mm
 Proximal measurement >4.5mm

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 Surgically by removing bone away from proximity to restoration
margin or
 by orthodontically extruding the tooth thus moving margin away
from bone
 External bevel gingivectomy
 Apically displaced flap surgery with or without osseous reduction

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SURGICAL CROWN LENGTHENING
INDICATIONS
 Subgingival caries or fracture
 Inadequate clinical crown length for retention
 Unequal or unaesthetic gingival height

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SURGICAL CROWN LENGTHENING
CONTRAINDICATIONS
 Surgery would create an unaesthetic outcome
 Deep caries or fracture that requires extensive bone removal on
contiguous teeth
 Tooth is poor restorative risk

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SURGICAL CROWN LENGTHENING MAY INCLUDE
 Removal of soft tissue
 Indication: if attached gingiva is adequate and more than 3mm of
tissue coronal to bone crest.
 Procedure done : Gingivectomy
 Removal of both soft tissue and bone
 Indication : inadequate attached gingiva and > 3mm of soft tissue
requires flap surgery and bone recontouring
 Procedure done: Apically positioned flap with or without osseous
recontouring

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Gingivectomy

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Apically positioned flap

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SURGICAL CROWN LENGTHENING
Associated complications –gingival
recession, interpapillary
recession..unaethetic triangle formation

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ORTHODONTIC EXTRUSION
 Orthodontic extrusion low orthodontic extrusion force tooth erupts
slowly bringing alveolar bone and gingival tissue with it
 Tooth is stabilised in new position and then treated with surgery to
correct bone and gingival tissue levels.
 Rapid orthodontic extrusion: tooth is erupted to desired amount
over weeks
 Supracrestal fiberotomy is performed around tooth to prevent tissue
and bone from following the tooth
 Tooth stabilised for 12 weeks to confirm position of tissue and bone.

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MARGIN PLACEMENT GUIDELINES
USING SULCUS DEPTH AS GUIDELINE TO PLACE MARGIN
 Rule 1: if sulcus depth is 1.5mm or less ,place restorative on
margin 0.5mm below the gingival tissue crest.
 Rule 2: if sulcus is more than 1.5mm, place margin half the
depth of sulcus below the tissue crest.
 Rule 3:if sulcus is greater than 2mm, evaluate to see if a
gingivectomy could be performed to lengthen the teeth and
create a 1.5mm sulcus.

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 Is biologic width important??????
 Which type of caries treatment biologic width should be given
importance???????
 What is biologic width???
 What is the value for biologic width???
 What happens if biologic width is violated?????????
 What are different categories of biologic width???????
 How do we know that biologic width is violated??
 Can biologic width violation be treated??????

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THANK YOU