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Treating black triangles

by Dr. Clark Nov 01, 2013 Microscope Enhanced Dentistry Not tagged yet...

Sometimes a particular case comes along that appears, at first glance, overwhelming.  This case fits that description. (Fig1-3)  However, when this patient emailed my office and inquired regarding flying across the country to have me treat him, I had fortunately done many cases involving hundreds of teeth using the Bioclear matrix system to treat dentitions afflicted with black triangles, albeit none of this magnitude. I felt absolutely confident that we could achieve a good outcome.  The trick was to disassemble the case into bite sized pieces. This case presents many excellent questions and the additional challenge of severe facial abrasions.  I will first review background of black triangles and of lower incisor complications and then proceed with the presentation of the clinical procedures used to treat this particular patient.

Fig 1

 Fig 1) Preoperative view of black triangle case.  Notice the pursing of lips and forced smile of a patient who is embarrassed of the esthetics of the lower teeth

Fig 2 Crop

Figure 2) The receded papilla height of the anterior teeth was not significantly lower than that of the posterior teeth, ruling out a surgical approach

Fig 3


Figure 3) This view demonstrates the unique “twisted butter knife” anatomy of the lower incisor tooth

Black Triangles: Prevalence and Patient Attitudes

One third of adults suffer from black triangles, or more appropriately referred to as open gingival embrasures. 1   Besides being unsightly and prematurely aging the smile, black triangles are prone to accumulate food debris and excessive plaque. 2  A recent study of patient attitudes found patient dissatisfaction with black triangles to rank quite highly among esthetic defects ranking third following carious lesions and dark crown margins.3  If you go online and Google “dental black triangles”,  you will view hundreds of patient black triangle questions, and of patient complaints and lawsuits resultant from adult orthodontic cases and post-periodontal therapy papilla loss.  This clinical and esthetic dilemma demands more attention from our profession.  The caveat is that until now, there has been no easy, minimally invasive approach for treatment.  Today, instead of improvising and struggling, I have developed a specific predictable protocol to treat this problem.

 Lower Incisor Esthetics

The esthetics of the lower teeth are often overlooked or simply ignored by many dentists.  Recently a fellow passenger seated next to me on a flight was intrigued by the photos that were on my laptop.  He asked “Why do dentists only seem to treat the upper teeth when the lowers look all jacked up?  Do they think no one notices?  It looks ridiculous to have perfect top teeth and ugly bottom teeth!”

In addition, as we age, the lower incisors become more visible as the facial muscles change,

Why do so many dentists mistrust composite to treat black triangles?

Like many clinicians, Michael’s dentist in North Carolina hadn’t heard of Bioclear and was unfamiliar with injection molding of composites.  Therefore, he was leery of treating Michael with “bonding”.  At that point Michael decided to cross the country for a different solution because porcelain veneers and periodontal surgeries did not appeal to him as ideal treatments. After he saw the my “Black Triangle“ articles on the internet and videos on YouTube, he opted to fly to the west coast for treatment.

After spending many hours working with manufacturers and tens of thousands of dentists I have compiled “a top 5” list of composite and porcelain fallacies that have steered dentists away from minimally invasive composite treatments for black triangles or has doomed their previous attempts leaving them gun-shy to try it again

1)” Acid Etching cleans the tooth”. False.  Phosphoric acid barely touches plaque. Biofilm is so tenacious, and we forget that phosphoric acid removes the mineral, not the organic component of tooth surfaces.  Biofilm is organic, not a mineral.  This residual biofilm at the margins is likely the number one reason why class V and interproximal composites turn brown at the margins.  No bonding agent can bond to biofilm, and most dentists are leaving biofilm on their hard to access margins.

2) “A stronger dentin bonding agent is the answer”.  False.  They (the manufacturers) keep selling us new and improved dentin bonding agents with higher and higher dentin bond strengths.  The problem is twofold, first of all in a case like this, most dentists are bonding to plaque, calculus,and contaminated dentin and no resin bonds to biofilm.  Secondly, with the Bioclear approach; uncut, blasted, and rinsed etched enamel is leveraged to provide the bulk of the retention and reliance on the dentin is lessened.  We can trust enamel bonding

3) “A full crown is better”. False.  If you were the patient with otherwise healthy teeth, would you choose full crowns?  Consider that a full crown destroys 70% of coronal tooth volume with a 10-20% chance of eventual resultant pulpal death.

4) “A porcelain veneer is better than bonding”. In a case like this, False.  First, porcelain veneers cannot reach far enough to the lingual, so the space is blocked from view but becomes a plaque trap on the lingual.  Secondly, bonding a veneer to this much cervical enamel should make you nervous.  Very nervous.

5)” Direct bonding is too difficult”.  In the past this may have been true.  But today, False. In the modern resin era, we  utilize  anatomic Bioclear matrices injection molded with an excellent microfill like Filtek Supreme Ultra, creating and idael a  flowable/paste interlace. 



Figure 10


Figure 10) 37%  Phosphoric acid etchant (3M) is injected under the matrix on to the tooth.  The entire tooth should be etched.



 Fig 12Fig 14

Gross finish with carbide burs, flame diamonds, and a coarse Soflex Disc (3M)

 The Clark 30 second Rock Star polish. A. Marginate with Brownie, B. Matte finish with coarse pumice and cup, C. High shine with Jazz Polisher (SS White).

The Mirror Finish-Taking the Case from Good to Great

Having a mirror smooth composite finish makes everyone happy; the patient, the soft tissue and especially you, the clinician.  The matte or grainy finishes of the past collect lipstick, biofilm, stain, and feel like cheap dentistry to the patient’s tongue.  In the past, only porcelain stayed smooth.  Those days need to end now.  The first step is using a microfill that holds its shine.  I am nearly always disappointed at how miserable the composite finishing systems are that I am asked to evaluate, and how disappointing many of the composite finishes that are presented in dental journals and magazines.  The folks at Kerr, 3M, and SS White have commented that they have never seen polishes like the ones I show in my lecture.  That’s probably because most doctors a manufacturers “system” and frankly those systems are mediocre at best and grossly overcomplicated. 


Before the Bioclear matrix and a disciplined approach to composite treatment of black triangles, many treatments ended with significant compromise in periodontal health.  Many cases deboned soon after placement. Others suffered problems with stain.  The interdental papilla serves as both a functional and aesthetic asset.  Anatomically ideal interproximal composite shapes that are mirror smooth can serve as a predictable scaffold to regain this valuable gingival architecture.  However, the reader is cautioned that to attempt this elective procedure using no magnification, without a strict adherence to dentin detoxification with a blasting appliance, and using a flat matrix/no matrix; non treatment or referral is recommended.  Slowly, our profession is changing its thought processes, retraining its hands and expanding its armamentarium to perform techniques that were previously impossible.


1)  Kurth J, Kokich V.  Open Gingival Embrasures after orthodontic treatment in adults: prevalence and etiology. Am J Orthod Dentofacial Orthop 2001; 120:116-123

2)  Ko-Komura N, Kimura-Hayasi M et al. Some factors associated with open embrasures following orthodontic treatment. Aust Orthod J 2003; 19:19-24

3)  Cunliffe J, Pretty I.  Patients ranking of interdental “black triangles” against other common esthetic problems. Europ J Pros Rest Dent. 12/2009; 17(4):177-181


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