The biological width is defined as the dimension of soft tissue attached to the tooth coronal to the alveolar bone crest, including the sulcus depth, epithelial attachment, and connective tissue attachment. It typically measures around 2.04 mm. Violation of the biological width can occur when restorations are placed too far subgingivally and can lead to inflammation and bone loss. Surgical crown lengthening and orthodontic extrusion are techniques used to correct biological width violations. Maintaining the biological width is important for peri-implant health as well.

1. BIOLOGICAL
WIDTH
BY
Dr. Ali Mohammed Mahdi

2. -The Biological Width is defined as the
dimension of the soft tissue, which is attached to
the portion of the tooth coronal to the crest of
the alveolar bone.
Sulcus depth 0.69 mm
Epithelial attachment 0.97
Connective tissue attachment 1.07 mm
Biological Width = 2.04

3. Bermuda Triangle VS Biological Width
In dentistry the area of biological width along with sulcus, around natural teeth or an
implant is sometimes called
Bermuda Triangle or Devil’s Triangle
It extends from gingival crest, with tooth/implant on one side and
biological width on the other side

4. -BW encroachment becomes a major concerning factor when there is an indication of
the restoration of a tooth that has been fractured or has deep caries near the alveolar
crest area
-The ectodermal tissue present in the body acts as a protective barrier against the
invasion of bacteria and other foreign particles
-The function of junctional epithelium was investigated by Sanz (1991) in a
comparative histologic study of healthy and infected implant sites, revealing high
transmigration of inflammatory cells (increase of T-lymphocytes) in sulcular
epithelium of infected sites
-Chavrier(2000) in his histologic biopsy study on the connective tissue around
implants revealed predominance of type 1 collagen fiber, this type of fiber is the
most abundant protein in mineralized tissues and is also the main ECM organic
component
Function of Biologic Width

5. CATEGORIES/PROFILES OF BIOLOGIC WIDTH
Kois(2000) proposed three categories of biologic width based on the total dimension of
attachment and the sulcus depth following bone sounding measurements
Normal crest High crest
Low crest

6. CATEGORIES/PROFILES OF BIOLOGIC WIDTH
Importance of determining the crest category
When preparing anterior teeth for indirect restorations, it is essential that
the dentist should know about the Crest category. This allows the operator to
determine the optimal position of margin placement, as well as inform the
patient of the probable long-term effects of the crown margin on gingival
health and esthetics.

7. Based on the sulcus depth the following
three rules can be used to place intra-
crevicular margins:
1) If the sulcus probes 1.5 mm or less, the
restorative margin could be placed 0.5
mm below the gingival tissue crest.
2) If the sulcus probes more than 1.5 mm,
the restorative margin can be placed in
half the depth of the sulcus.
3) If the sulcus is greater than 2 mm,
gingivectomy could be performed to
lengthen the tooth and create a 1.5 mm
sulcus.
Margin Placement

8. The health of the periodontal tissues is dependent on properly designed restorations.
Incorrectly placed restoration margin and unadapted restoration violates the biologic
width. If the margin must be placed subgingivally, the factors to be taken into
account are[Nugala, B. Et al.(2012)]:
-Correct crown contour in the gingival third
-correct polishing and rounding of the margin
-sufficient zone of the attached gingiva
-no biologic width violation by the margin.

9. Evaluation of Biological Width Violation
The signs of biologic width violation are:
-Chronic progressive gingival inflammation around the restoration
-Bleeding on probing
-Localized gingival hyperplasia with minimal bone loss
-Gingival recession
-Pocket formation
-Clinical attachment loss and alveolar bone loss
-Gingival hyperplasia is most frequently found subgingivally placed
restoration margins.

10. Evaluation of Biological Width Violation
Clinicalmethod
Bone sounding
Radiographic evaluation

11. Clinicalmethod
Biological width is determined in clinics using periodontal probe.
If a patient experiences tissue
discomfort when the
restoration margin levels are
being assessed with a
periodontal probe, it is a good
indication that the margin
extends into the attachment
and that a biologic width
violation has occurred.

12. Bone sounding / Transgingival Probing
The biologic width can be
identified by probing under local
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.

13. Radiographic Evaluation
Radiographic interpretation can be very helpful to the clinicians in identifying
interproximal violations of biologic width. However, radiographs are not
diagnostic on the mesio-facial and disto-facial line angles of teeth, because of tooth
superimposition.

14. Correction of Biological Width Violation
1. Surgical crown lengthening
• Gingivectomy
• Apically positioned flap (APF)
• APF with osseous reduction
2. Orthodontic procedure
• Forced eruption
• Forced eruption combined with fiberotomy
• Orthodontic Extrusion associated with Supracrestal
Fiberotomy and Root Planing (OEFRP)

15. Surgical crown lengthening
Indications
1. Inadequate clinical crown for retention due to
extensive caries, subgingival caries or tooth fracture,
root perforation or root resorption within the
cervical 1/3rd of the root in teeth with adequate
periodontal attachment.
2. Short clinical crowns.
3. Unequal, excessive, or unesthetic gingival levels
for esthetics.
4. Teeth with excessive occlusal wear or incisal wear.
5. Teeth with inadequate interocclusal space for
proper restorative procedures due to supraeruption.
6. Restorations which violate the biologic width.
Contraindications
1. Deep caries or fracture requiring
excessive bone removal.
2. Tooth with inadequate crown root
ratio.
3. Non-restorable teeth.
4. Tooth with increased risk of furcation
involvement.

16. External bevel gingivectomy is both
successful and predictable surgical
procedure and is indicated in
hyperplasia or pseudopocket along
with presence of adequate amount of
keratinized tissue. Internal bevel
gingivectomy is carried out if
reduction of excessive pocket depth
and exposure of coronal tooth is
required in absence of sufficient zone
of attached gingiva.
Gingivectomy

17. Apically positioned flap is recommended
when crown lengthening of multiple teeth
in a quadrant or sextant of dentition is
required and there is a biologic width of
more than 3 mm. Pocket reduction can be
done at the same surgery. It should not be
done for during surgical crown lengthening
of a single tooth in the esthetic zone.
Apically positioned flap (APF)

18. Apically positioned flap with osseous reduction
It is the most common procedure for
clinical crown lengthening. It is done in
inadequate zone of attached gingiva
and biologic width less than 3 mm.
Detailed evaluation should be done
before carrying out osseous reduction
as it compromises periodontal support
of the tooth, causes furcation
involvement, poor crown-to root ratio
and gingival recession. It should not be
done during surgical crown
lengthening of a single tooth in the
esthetic zone. In such cases, forced
eruption should be considered to
prevent negative architecture.

19. Complications after crown lengthening
a) Poor aesthetics due to ‘black triangles’
b) Root hypersensitivity
c) Root resorption
d) Transient mobility of the teeth

20. Bertoldi et al.2019 Clinical study Clinical and histological response. Assessed the response of periodontal tissues to
sub-gingival restorations when compared with untreated root surfaces.
DME was applied on 29 teeth with sub-gingival cavities. With respect to biological width and following a firm
supportive therapy, DME is compatible with periodontal tissues.
Frese et al.2014 Review and case report - Presented a step-by-step technique for DME in a case where
biological width was invaded.
The 12-month follow-up period showed no signs of hard or soft tissue inflammation.
Dablanca-Blanco et al. 2017 Case reports -Discussed seven different scenarios of molars with deep sub-
gingival margins, their treatment approaches, and the indication for DME vs. SCL.
Whenever optimal matrix placement can be achieved, the DME technique can be used.
Otherwise, in deeper cavities that invades the BW, SCL is recommended.
A current case report (Mugri et al. 2021)assessed SCL vs. DME and recommended DME for deep cavities
as a better alternative to SCL. However, this conclusion is solely based on the biological width outcome,
not on the successful retention or the survival rate .
Sharon K. Lanning et al. (2003) suggested that During surgical crown lengthening, the bone level was
lowered for placement of the prosthetic margin and reestablishment of the biological width. The biological
width, at treated sites, was reestablished to its original vertical dimension by 6 months.
BW,DME&SCL STUDIES

21. -The formation of biological width around implant is a
complex process after several weeks of healing. The
biological width around implant is a 3-4mm distance from
the top of the peri-implant mucosa to the first bone-to-
implant contact or the stabilized top of the adjacent bone,
consisting of sulcular epithelium, junctional epithelium
and fibrous connective tissue between the epithelium
and the first bone-to-implant contact or the stabilized top
of the adjacent bone.
-Vervaeke S et al. (2018) suggested that The
reestablishment of biologic width confirms the vertical
position of the implant seemed highly successful to avoid
implant surface exposure
Biological Width Around Implants

22. - Lanning et al. observed that the biological width is reestablished to its original dimension 6 months
after surgery, as well as when the amount of bone to be removed is based on the future margins of
the restoration and the original length of the biological width – definitive restorations may be
performed 3 months after treatment (even in esthetic areas).
Biological Width Around Implants

23. THANK
YOU