The Biologic Width

8/10/2019 The Biologic Width

1/21

THE BIOLOGIC WIDTH


2/21

INTRODUCTION

For restoration to survive long term the periodontium

must remain healthy so that teeth are maintained.

For the periodontium to remain healthy restoration

must be critically maintained so that they are in

harmony with their surrounding periodontal tissue.

To maintain and enhance the

patients estheticappearance the tooth-tissue interface must present a

healthy natural appearance.


3/21

MARGIN PLACEMENT AND BIOLOGIC WIDTH

SUPRAGINGIVAL MARGIN EQUIGINGIVAL MARGIN SUBGINGIVAL MARGIN

Placed in non-

esthetic areas

Least impact on

periodontium

At the crest of

marginal gingiva.

More impact on

periodontium.

More plaque

retentive gingival

inflammation

Below the gingiva.

Greatest biologicrisk.

May violate the

gingival attachment

apparatus.


4/21

BIOLOGIC WIDTH

Biological width is defined asthe physiologic dimension of

the junctional epithelium &

connective tissue attachment.

The dimension of space that

the healthy gingival tissue

occupy above the alveolar bone

is now identified as the biologic

width.

This term was based on the

work of Gargiulo et al. (1961).


5/21

WHY RESTORATION EXTENDS SUBGINGIVALLY?

For adequate resistance andretention form.

To make significant contact

and contour.

To mask the tooth-restorationinterface gingivally.


6/21

RESPONSE TO THIS INVASION

Unpredictable bone loss

Gingival inflammation


7/21

EVALUATION OF BIOLOGIC WIDTH

Clinical method

If a patient experiences

tissue discomfort when

the restoration margin

levels are being assessed

with a periodontal

probe, it is a good

indication that themargin extends into the

attachment and that a

biologic width violation

has occurred.


8/21

Bone sounding

The biologic width can be identified by probing underlocal anesthesia to the bone level (referred to as

"sounding to bone") and subtracting the sulcus depth

from the resulting measurement.

If this distance is less than 2 mm at one or more

locations, a diagnosis of biologic width violation can be

confirmed.

This measurement must be performed on teeth with

healthy gingival tissues and should be repeated on

more than one tooth to ensure accurate assessment,

and reduce individual and site variations.


9/21


10/21

Radiographic evaluation

Radiographic

interpretation can

identify interproximal

violations of biologicwidth.

However, on the

mesiofacial anddistofacial line angles of

teeth, radiographs are

not diagnostic because of

tooth superimposition.


11/21

METHODS TO CORRECT BIOLOGICWIDTH VIOLATION

Can be corrected by

1. Surgical crown lengthening

2. Orthodontic technique


12/21

SURGICAL CROWN LENGTHENING

Indications Subgingival caries or fracture

Inadequate clinical crown length for retention

Unequal or unesthetic gingival heights

Contraindications

Surgery would create an unesthetic outcome.

Deep caries or fracture would require excessive

bone removal on contiguous teeth.

The tooth with a poor restorative risk.


13/21


14/21

Apically repositioned flap surgery

Indication

Crown lengthening of multiple teeth in a

quadrant or sextant of the dentition, root caries,fractures.

Contraindication

Apical repositioned flap surgery should not be

used during surgical crown lengthening of a single

tooth in the esthetic zone.


15/21

With less than 3 mm of soft tissue between the bone and

gingival margin, or less-than-adequate attached gingiva, a flap

procedure and osseous recontouring are required for crown

lengthening.


16/21

Apically repositioned flap without osseous resection

Indication: When there is no adequate width of attached

gingiva, and there is a biologic width of more than 3 mm on

multiple teeth.

Apically repositioned flap with osseous reduction

Indication: When there is no adequate zone of attached

gingiva and the biologic width is less than 3 mm.

The alveolar bone is reduced by ostectomy and osteoplasty.As a general rule, at least 4 mm of sound tooth structure

must be exposed, so that the soft tissue will proliferate

coronally to cover 2-3 mm of the root, thereby leaving only 1-

2 mm of supragingivally located sound tooth structure.


17/21

ORTHODONTIC TECHNIQUES

The extrusion can be performed in two ways.

1) Low orthodontic extrusion force: The tooth is eruptedslowly, bringing the alveolar bone and gingival tissue with

it.

The tooth is extruded until the bone level has been

carried coronal to the ideal level by the amount that will

need to be removed surgically to correct the attachment

violation.

The tooth is stabilized in this new position and then is

treated with surgery to correct the bone and gingival

tissue levels.


18/21

2) Rapid orthodontic extrusion : The tooth is erupted tothe desired amount over several weeks.

During this period, a supercrestal fiberotomy is performed

weekly in an effort to prevent the tissue and bone fromfollowing the tooth.

The tooth is then stabilized for at least 12 weeks to

confirm the position of the tissue and bone, and anycoronal creep can be corrected surgically.


19/21

HEALING AFTER CROWN LENGTHENING

Restorative procedures must be delayed until newgingival crevice develops after periodontal surgery.

In non-esthetic areas : 6 weeks healing period post

surgically prior to final restorative procedures isrecommended.

In esthetic areas: A longer healing period is

recommended to prevent recession (4- 6 months).

The margin of the provisional restoration should not

hinder healing before the biologic width is established by

surgical procedures.


20/21


21/21

Documents

The Biologic Width