Black Triangle Closure Made Easier
A minimally invasive approach using anatomical matrices, warmed flowable and sculptable composite.
Closing black triangles between anterior teeth can be challenging, particularly when attempting to achieve natural contours in the interproximal and gingival regions.
In this clinical case, Dr Michael Cai demonstrates how the Bioclear Method, combined with heated composite materials, can simplify this restorative procedure.
The case involved lower anterior black triangles following orthodontic treatment. Using Bioclear anatomical matrices, the spaces were restored without removing healthy tooth structure.
Lower anterior open gingival embrasures following orthodontic alignment.
Why Can Black Triangle Closure Be So Challenging?
Black triangles are open gingival embrasures that can develop when the interdental papilla does not completely fill the space between adjacent teeth.
Post-Orthodontic Spaces
Following orthodontic alignment, differences in tooth shape, contact position and gingival anatomy can leave visible spaces between the teeth.
Difficult Interproximal Access
Traditional freehand composite placement can be difficult when attempting to build natural contours towards the gingival margin.
Gingival Emergence Profiles
Closing the visible gap requires careful control of the emergence profile, contact area and final restorative surface.
The restorative challenge:
Successful treatment requires more
than simply placing composite
into an open embrasure.
The shape of the restoration,
its relationship with the
gingival tissues and its
cleansability are all important.
Case Study: Lower Anterior Black Triangles
Dr Cai describes the treatment of a patient who developed black triangles following approximately 12 months of orthodontic treatment.
A Patient Seeking a Conservative Solution
A male patient in his mid-30s presented requesting improved aesthetics of his lower anterior teeth.
He had undergone fixed orthodontic treatment to correct moderate to severe anterior crowding.
Although pleased with the alignment achieved, he was concerned about the dark triangular spaces that had become visible between his lower incisors.
An initial referral to a periodontist was made to consider gingival and bone grafting.
However, this approach was considered unpredictable for the individual case.
Indirect restorations, including veneers and crowns, were also considered. These would have required more substantial tooth preparation to achieve the desired result.
The patient therefore opted for a minimally invasive direct composite approach.
Clinical planning consideration:
The patient also had
a fixed lingual orthodontic
retainer.
This was removed before
restorative treatment
and subsequently reapplied.
Managing existing retainers
is an important practical
consideration when reshaping
anterior teeth following
orthodontics.
Before & After: Closing the Black Triangles
The clinical photographs illustrate the changes achieved using Bioclear matrices and warmed composite injection techniques.
The Clinical Outcome
Dr Cai reports that the use of Bioclear anterior matrices helped create appropriate anatomical contours.
The combination of Filtek Supreme Flowable composite and warmed Filtek Supreme XTE sculptable composite allowed material to adapt around the interproximal surfaces of the lower incisors.
The shade selection also presented a challenge, with a B1 composite used to achieve the final aesthetic result.
Following finishing and polishing, the patient achieved the desired improvement without the need for tooth reduction in this case.
Interpreting the outcome:
These clinical images demonstrate
the result achieved in
one individual case.
The original publication
does not provide
long-term follow-up
establishing restoration
survival or
periodontal outcomes.
The Clinical Technique: Step by Step
The original publication illustrates the procedure from isolation and matrix placement through to composite injection and polishing.
Isolation
Rubber dam isolation was established to protect the soft tissues and provide a controlled restorative environment.
Biofilm Removal
Meticulous surface cleaning was undertaken before bonding to support adhesion to uncut enamel and the intended infinity-edge margins.
Matrix Placement
Bioclear anterior matrices were positioned around the teeth to guide the planned interproximal contours and emergence profiles.
Etching & Bonding
Scotchbond Universal etchant and adhesive were used according to the clinical sequence described in the original publication.
Composite Placement
Filtek Supreme Flowable was injected, followed by warmed Filtek Supreme XTE sculptable composite, before light curing.
Finishing & Polishing
The matrices were removed and the restorations were finished and polished. The fixed lingual retainer was subsequently replaced.
Two distinctive features of this case:
No local anaesthesia
was required because
the restorative procedure
did not involve
tooth reduction.
The selected Bioclear
matrix arrangement
also did not require
wedges for stabilisation.
These details describe
this particular procedure,
rather than universal
requirements for
black triangle treatment.
Combining Flowable & Warmed Sculptable Composite
A central feature of Dr Cai's technique is the combination of two composite consistencies within the anatomical matrix system.
Scotchbond Universal
Used as part of the adhesive protocol before composite placement.
Effective bonding to the prepared tooth surfaces was an important part of this minimally invasive technique.
Filtek Supreme Flowable
The flowable composite was injected into the matrix system to assist material adaptation around the interproximal tooth surfaces.
Warmed Filtek Supreme XTE
Warmed sculptable composite was placed following the flowable composite, helping form the restorative contours.
The published case used shade B1.
Why Warm the Composite?
Warming suitable composite materials can temporarily reduce their viscosity, making them easier to adapt within a matrix system.
In the published case, Dr Cai describes how the combination of flowable and warmed sculptable composite helped the material adapt around the interproximal surfaces of the lower incisors.
Material handling, temperature, curing and compatibility remain important. Clinicians should follow the manufacturer's current instructions for use.
Publication context:
These were the materials
used in Dr Cai's
original 2020 case.
They are not intended
to represent an exclusive
or current product
recommendation.
Modern Bioclear protocols
may use other compatible
adhesive and composite
systems.
Why Anatomical Matrices Are So Important
The shape of the restoration is one of the most challenging aspects of black triangle closure.
Beyond Traditional Freehand Bonding
Conventional composite placement using flat Mylar strips can make it difficult to reproduce appropriate cervical contours.
This becomes particularly challenging when working close to the gingival margin and attempting to create a longer interproximal contact area.
Bioclear's anatomical matrices are designed to help clinicians establish the intended restorative form.
Their curvature supports the development of the emergence profile and interproximal contours when the matrix is selected and positioned correctly.
The technique allows the clinician to use the matrix to guide the composite rather than relying entirely on freehand shaping.
Three Important Matrix Functions
1. Gingival Adaptation
The matrix helps
control the cervical
contour and adaptation
of the restoration
towards the
gingival margin.
2. Contact Area
Anatomical curvature
helps develop
an appropriate
interproximal
contact position
and relationship
between adjacent teeth.
3. Emergence Profile
The matrix guides
the transition
from the cervical
tooth surface
towards the
incisal portion
of the restoration.
The objective is not simply to close the space.
The final restoration
should have appropriate
contours, a manageable
contact relationship
and surfaces that
can be maintained
through effective
oral hygiene.
Individual periodontal
health and tooth anatomy
remain important
considerations.
What Makes This Approach Different?
Dr Cai's case demonstrates several potential advantages of using the Bioclear Method for suitable black triangle closures.
Minimally Invasive
In the published case, no healthy tooth structure needed to be removed to achieve the aesthetic improvement.
Anatomical Control
Bioclear matrices helped guide the restorative contours and interproximal anatomy.
Direct Restoration
The composite restorations were placed directly, avoiding the tooth preparation and laboratory stages associated with the indirect options considered for this patient.
The Five Pillars of the Bioclear Method
The technique shown in Dr Cai's case demonstrates several principles of the wider Bioclear restorative methodology.
Biofilm Removal
Thorough cleaning of bonding surfaces before adhesive treatment.
Preparation Design
Conservative preparation principles that prioritise tooth preservation.
Anatomical Matrices
Purpose-designed matrices to help control restorative form and emergence profiles.
Heated Injection Moulding
Controlled placement of suitable warmed composite materials within the matrix.
Rockstar Polishing
Systematic finishing and polishing of restorative surfaces.
Read Dr Michael Cai's Full Clinical Case
Unsightly Black Triangles: A Tricky Restorative Procedure Made Easy with Flowable Composites and Warming
Dr Michael Cai
3M Oral Care, 2020
Three-page clinical case report
Includes the complete clinical photographic sequence, treatment details, materials and final result.
Frequently Asked Questions
Common clinical questions about black triangle closure using anatomical matrices and warmed composite.
Can black triangles after orthodontics be closed with composite?
In suitable cases, black triangles following orthodontic treatment can be reduced or closed through additive composite restoration.
The clinician must consider tooth shape, periodontal health, the size of the embrasure and the desired restorative contours.
Why use Bioclear matrices for black triangle closure?
Bioclear anatomical matrices help guide composite placement and control the interproximal contours.
Their shape can assist with contact positioning, gingival adaptation and creating an appropriate emergence profile.
Why combine flowable and warmed sculptable composite?
In the published case, Filtek Supreme Flowable was followed by warmed Filtek Supreme XTE sculptable composite.
Dr Cai describes how this combination facilitated adaptation of the restorative materials around the interproximal tooth surfaces.
Is tooth reduction necessary for Bioclear black triangle treatment?
Not always. The published case was completed without removing natural tooth structure.
However, the preparation required in other cases depends on existing restorations, tooth anatomy and the individual clinical situation.
Does black triangle closure require local anaesthesia?
Dr Cai completed this particular case without local anaesthesia, as the procedure did not require removal of tooth structure.
Other patients may require anaesthesia depending on the clinical circumstances and treatment being provided.
Are wedges always needed with Bioclear black triangle matrices?
No. In this particular case, Dr Cai reported that wedges were not required to stabilise the matrices.
Matrix placement and stabilisation depend on the individual case and selected technique.
Can Bioclear regenerate the interdental papilla?
Composite black triangle closure primarily works by reshaping the tooth contours and reducing the visible open embrasure.
Gingival tissue changes may occur in some circumstances, but predictable biological regeneration of the interdental papilla should not be assumed.
What happens if a patient has a fixed orthodontic retainer?
Retainer management must be considered when planning anterior restorative treatment.
In the published case, the fixed lingual retainer was removed before composite placement and subsequently reapplied.
Where can dentists learn Bioclear black triangle closure?
Bioclear Matrix UK provides hands-on Black Triangle certification courses, covering matrix selection, emergence profiles, adhesive techniques, warmed composite injection moulding and polishing.
Continue Exploring Black Triangle Treatment
Discover more published clinical cases demonstrating the Bioclear approach to minimally invasive anterior restoration.
Learn to Close Black Triangles with Bioclear
Develop your understanding of anatomical matrix selection, gingival emergence profiles and composite injection moulding.
Our hands-on Black Triangle certification course provides practical training in simple and complex black triangle closures.
Explore Black Triangle Training →Unhappy with Black Triangles Between Your Teeth?
If you have black triangles following orthodontics or changes in your gum tissues, Bioclear may offer a conservative restorative option.
A dentist with relevant Bioclear training can assess your teeth and explain which treatment options may be appropriate.
Find a Bioclear Dentist →