Gaps Between Teeth and Black Triangles

Gaps between teeth have four common causes, each with its own fix. Spacing between normal-sized teeth is an alignment problem and is closed with Invisalign. Small or peg-shaped teeth are built up with bonding or veneers. A missing tooth is replaced with an implant, a bridge or a partial denture. Dark triangles at the gum line, common after adult orthodontics or gum recession, are closed with the Bioclear bonding technique. The right fix matches the cause.

Why gaps appear

The teeth are the right size but in the wrong place. Spacing between normal-sized teeth, with or without a wider gap in the middle, is an alignment problem. The jaw has a little more room than the teeth fill, a thumb habit or the tongue pushed them, or the band of tissue behind the upper lip holds the two front teeth apart.

The teeth are small. Some people have naturally undersized teeth, most often the lateral incisors beside the two front teeth, which sometimes come through as narrow pegs. The spaces are left by teeth that are smaller than they should be.

A tooth is missing, from birth or from extraction, and the neighbors have drifted toward the gap or left it open.

The gum has receded. Between every two teeth, a small peak of gum normally fills the space above the contact point. When that gum shrinks back, from gum disease, from the bone loss that goes with it, or because straightened teeth that used to overlap now meet differently, a dark triangle opens at the gum line. These black triangles are especially common after orthodontic treatment in adults and bother many people.

The right fix for each

Spacing between normal teeth: move them. When the teeth themselves are fine and only apart, the least invasive answer is alignment, usually with Invisalign, planned by Dr. Hong, our board-certified orthodontist. Nothing is added to the teeth and nothing is removed. Retainers afterward keep the spaces closed.

A modest gap on well-placed teeth: bonding. A small space between the front teeth can be closed by adding a little composite to the edge of each tooth, shaped and polished in the chair in one or two visits, usually without anesthesia or preparation. Composite bonding is our preference for a single gap or a single small tooth; it is quick and minimally invasive and looks very good when the teeth around it are a normal shade.

Small teeth: build them up. An undersized lateral incisor is one of our favorite bonding cases: the whole tooth is built out to its proper size with a composite facing, no drilling needed. When several teeth are small and spaced, porcelain veneers usually serve better: they are more lifelike, do not stain and last longer across multiple teeth, and because we are making the teeth bigger rather than smaller, very little enamel needs to be removed. Naturally small teeth with gaps are among the best cases for veneers there are.

Black triangles: Bioclear. Ordinary bonding at the gum line leaves a ledge that traps plaque and inflames the gum, which is why black triangles have a reputation for being hard to close. We use the Bioclear matrix technique: a clear, anatomically shaped form wraps the tooth below the gum line and lets us shape the composite in one smooth, continuous contour from the root surface out to the contact point, with nothing for floss to catch on. The result follows the natural contour of the tooth and is easy to keep clean. Gum health has to be settled first, and not every triangle closes completely, but for the right case it is a good treatment.

A missing tooth: replace it. When the gap is a missing tooth, the choices are an implant, a bridge or a partial denture, and our missing tooth page compares them. If the neighbors have drifted, alignment may be needed first to reopen the right amount of space.

The order of treatment

For most spacing cases the sequence is the same:

1. Treat the gums.
2. Align, if the position is the problem.
3. Whiten, so the shade is set.
4. Add shape only where it is still needed, with bonding or porcelain.

That order protects the teeth and avoids building restorations on a problem that alignment would have solved. Our cosmetic dentistry page explains the thinking behind it.

Frequently asked questions

Can a gap between my front teeth be closed without braces?

Often, with composite bonding added to the edges of the two teeth, in one or two visits with no preparation. It suits a modest gap on teeth that are otherwise in the right place. A wide gap, or teeth that are also crooked, is usually better moved with Invisalign first.

What are the dark triangles between my teeth?

Spaces where the gum no longer fills the gap between two teeth near the gum line, usually after recession, after gum disease has cost some bone, or after orthodontic treatment has straightened teeth that used to overlap. We close them with the Bioclear matrix technique.

Will the gap come back?

A gap closed with bonding or veneers stays closed as long as the restoration lasts. A gap closed by moving the teeth comes back if the teeth drift, which is why retainers after orthodontic treatment are worn for life.

My teeth are small with spaces all round. Bonding or veneers?

For one or two small teeth, bonding. For several, porcelain veneers: naturally small teeth are one of the best cases for veneers, because we are adding rather than removing, and the result is more lifelike and lasts longer than composite across many teeth.

Should I whiten before closing a gap?

Yes. Bonding and veneers are matched to the color of your teeth and do not change afterward, so the shade is settled first.