Managing ‘Kissing Contacts’

I have a couple of questions for you. When you get up in the morning and prepare for the office, are there any procedures you do not look forward to, do not want to think about, or just downright dread?

Of course, the answer is a resounding “yes” for all of us, both young and old, the green and the experienced. In fact, depending on what we felt least comfortable with after dental school may help create that bias, correct?

So much of this can be borne from early experiences, which leaves us apprehensive. Let us name a few: molar endo, mandibular tissue-supported complete dentures, cutting a distal box on a first or second molar with long, broad, tight contacts, and so on. These are all challenging. Some of us shy away over time from what we struggle with, while others address their weaknesses until they elevate toward proficiency.

What is interesting is that dental school teaches us so much, yet prepares us for so little, largely because there just is not enough time to scratch the surface of our craft (I spend more time on this thought in a previous article). This leads to my other question: In using words like craft or trade, do you sometimes feel more like a mechanic or an artist during the work day? Like a skilled laborer or maestro? It is interesting how we can feel like both examples during the day, going from procedure to procedure, and like both during a singular procedure:

• The mechanic: Dealing with any posterior teeth, cutting preps, chasing caries, placing matrices around teeth, etc.
• The maestro: Finishing crown preps, beveling anterior cavo-surface margins, creating beautiful occlusal contacts
• Toiling over tooth design and display, sculpting a class IV

While using amalgam for multi-surface posterior restorations is still widely used and taught throughout the world, we have become more and more comfortable employing composite as the material of choice once the decision is made to place a direct posterior restoration.

Composite is predictable and attractive to both clinician and patient. As years pass, as we play the role of the mechanic, we appreciate the changes in composite and adhesive advancements:

• Increased crushing strength
• Increased tensile strength
• Increased shearing strength
• Decreased polymerization shrinkage
• The durability in the change from microhybrids to nanohybrids

And the maestro, or artist, in us appreciates:

• The smoothness in trimming and sculpting cavo-surface margins and line angles
• The high “polishability” with less effort than years before

But, but, but ...

There is always a “but,” isn’t there? The ability for amalgam to be packed and condensed and burnished, especially in Class II and III circumstances, allows for an ideal mechanical technique to assure a predictably tight contact. Having placed many in my day – even with the accompaniment of a Toffelmyer matrix, once-used exclusively decades ago – you can create a nice tight contact that can serve the patient well for some time. However, I have not practiced using amalgam in nearly 20 years.

Quick aside: There is certainly nothing wrong with it – just a personal desire to pursue adhesive therapy and received no pushback from my patient base. Except for Scott. He was the last patient I ever placed an amalgam in – and I placed many for him, since his was a benefits decision. That was 1999. I replaced most of them at his behest last year and earlier this year. He could not understand why he ever thought that way. Twenty years will make anyone think different. Just thought it was a funny anecdote to share.

With the exceptions of a core paste or two – or our dear friend Geristore, as dual cure resins do allow for condensing – it is abundantly clear that we cannot burnish composites in Class II or Class III restorations in order to create a tight interproximal contact in the same fashion. Even more evident are those clinical situations where we have two or greater interproximal contacts in a row in a quadrant requiring restorations at one time: A mesial and distal contact of two adjacent teeth or more.

There can be challenges or dilemmas in delivering predictably tight and well-contoured proximal contacts and contours using composite. The advent of sectional matrices, variations in wedges and evolving steps in techniques, allow for creating well-crafted restorations you can be proud to carve your initials in (old dental school humor).

This article touches on ways to predictably deliver tight and well-contoured contacts from composite and what some refer to as “kissing contacts.” Prior to last year I never heard of them referred to as “kissing contacts.” There has been online interest in receiving input for improving these contacts.

Please understand it is not possible to highlight all the companies who market their own sectional matrices or systems, nor expand on the seemingly infinite composites available. For the techniques provided within, materials include:

• 3M Filtek Supreme Ultra
• 3M Filtek Bulk Fill Flowable
• Geristore
• Clearfil Protect
• Scotchbond Universal
• Garrison Dental sectional matrix systems (all types)
• Garrison composite 3D Fusion wedges
• Traditional wooden wedges
• 5 percent glutaraldehyde (such as MicroPrime G from Danville Materials)

The Preparation

Due to adhesives and the strength of composite resin, we may be very conservative in our preparations relative to the narrative preached in using amalgam – extension for prevention, and 3/4 mm into dentin. Remember? One trick in conservativism is pre-wedging (placing a wedge prior to prepping the box). However, in preparing proximal boxes we still need to prepare to:

• Have a box floor that is smooth to limit surface tension and not leaving a reverse “J” at the margin
• Prep lateral to flared walls at the cavo-surface margin of the box and avoid leaving unsupported enamel rods, since these areas will wear and break easily, which leads to a loss in marginal integrity at the line angles
• Allow for enough room by breaking contact to line angles enough room for placing the sectional matrix, even with pre-wedging

Tip: I finish all my direct composite preparations with a fine diamond from the Restorative Design bur block – an 018, 016 or 012, along with an electric handpiece at a slow setting. It is very important that the matrix bands do not get stuck and move freely into the sulcus, which creates a seal so the matrix retainer has the best chance to achieve full adaptation. It also helps reduce surface tension at the bonding interface.

The Placement

The Matrix Band

Expanding on that last sentence, all molars and premolars do not share the same contacts and contours in all patients, correct? Further, they all do not erupt perfectly either, do they? Wouldn’t that be nice.

They can erupt mesial, distal, facial and lingual. Worse still is partial eruption. Even after orthodontic improvement, it may not reflect the cookie cutter, optimal examples shown on vendor websites.

Or throw in a first premolar after interproximal reduction (IPR) from Invisalign therapy. There will be issues. You must learn and recognize where any of these matrix bands, regardless of the system used, may get hung up on placement moving towards and beneath the gingival sulcus. Other factors affecting selection of bands with “kissing contacts” include:

• Molar with molar
• Molar with premolar
• Height of contact
• Width of contact
• Depth of contact
• Emergence profile
• Eruption and angulation

Below are images of some of the bands from Garrison and others I employ daily.

Placement should be completely passive (with or without pre-wedging) using slight pressure with college pliers. Pre-bending may be needed as not to get hung up on the gingiva at the line angles (much the way we ask patients to pull the floss past the contact, then wrap the floss around the tooth to follow its contours to get subgingival).

Selecting a band, even within one company’s system, can be maddening. Garrison’s choices are vast but so helpful. The images detail the possibilities. Often it is a personal choice of firmer, all-metal bands or the non-stick, coated metal bands that are softer and more malleable.

When you practice with these long enough, you realize you cannot have a personal bias of using just one style all the time because one feels more comfortable in your hands. I used to be that way until I explored and experimented with combinations making contouring and finishing and cleaning up so much easier, which helped predictability soar.

For example, I always used all-metal bands (first generation, if you will) no matter what. Removing them as I did multiple MODs became time-consuming and frustrating. There was a reason Garrison created the “next gen” coated ones. They behaved like eggs on a nonstick pan. The problem was the metal was sometimes too soft and floppy. Experiment and mix and match to find what is predictable for you.

The Wedge

Just as important is wedge selection and placement. Some work better than others depending whose sulcus you are in. Factors affecting selection with “kissing contacts” include:

• Molar with molar
• Molar with premolar
• Height of contact
• Width of contact
• Depth of contact
• Emergence profile
• Eruption and angulation

With a bevy of anatomical types and shapes available, you are bound to find what you need, so keep a variety of each. Notwithstanding are those classic triangular wooden wedges that still have a place. I still use them at some point each week. Keep an open mind about which wedges you expect to use, since you assuredly want your treatment trays set up ahead of time.

Have your assistant give you choices. You can autoclave what you do not use but, of course, discard what you do use. Ultimately, engage the band with the wedge from the box floor level to just subgingival. Below are images of some of the styles available, but the ones I employ daily.

These scales or gills on the above rubber wedges compress then grab as they move interproximally and hold the bands well.

With “kissing contacts,” we have the issue of fitting two matrices against each other sharing the same entry but slipping into two different sulci (yes, the plural of sulcus). In these cases, you may find resistance from the bands being pre-contoured or bowed for convexity. I have learned that placing the most distal of the two works best, since it can be braced against the prep with a finger or thumb while placing the adjacent matrix.

Placing the wedge is even more critical here and the bands can displace laterally or lift up from the sulci. I have also learned that using light finger pressure on your free index finger can be plenty to keep the bands in place while wedging. Use a mirror to verify the box floor of the prep is sealed and you see no “daylight” or the wedge at the margin. This ensures the band(s) moved coronally out of one or both sulci.

The Matrix Retainer

Your selection of retainers is equally important, since there once was no choice of retainers – all metal with short or longer prongs. But if your prep blew through line angles on both adjacent preps and you have an average-to-wide embrasure, those prongs may pinch the band, kink them, or move too inward, which causes a distortion of the final restoration at the line angles (left with an indentation, basically – and apologies for not having an image).

Again, when things are straight forward, it is a personal choice where nearly anything may work the same. Factors affecting selection of retainers include:

• Molar with molar
• Molar with premolar
• Width of contact
• Width of one or both preps
• Eruption and angulation
• Multiple teeth in a line or quadrant with multiple MODs – the ability to stack the retainers

The images below show three different generations of retainers from Garrison. Remember, the link to their website was listed earlier in the article. The retainers are positioned upside-down to appreciate the contours that engage the teeth.

Stacking older 3D XR was next to impossible since they were made too linear. The orange one helps with this, while the green aides in wider preps past line angles. Click on these links for videos:
https://garrisondental.com/en/instructional-video
https://www.youtube.com/watch?v=UADRIGxKRZA

The Fill

For optimal “kissing contacts,” filling the preparation is the most critical aspect of treatment, though each step determines how good the following one will be. Here is a detailed checklist (I love checklists) that can help ensure tighter contacts and more natural adjacent marginal ridge contours:

• Isolate teeth
• Place most distal matrix band not getting hung up
• Place the adjacent band not getting hung up, verify seal with mirror
• Place wedge while holding bands occlusally in place with index finger, verify seal with mirror
• Place matrix retainer, also holding bands occlusally in place with index finger, and verify seal with mirror (no sulcus tissue or wedge should be visible at the margin)
• Lightly use ball burnisher on both bands in a lateral movement and verify dry
• Etch (total, selective or self-etching); if one of the first two, rinse and verify dry
• Scrubbing of 5 percent glutaraldehyde (MicroPrime G or Gluma, for example) for 20 seconds inside entire prep, then blot dry and verify sheen
• Scrubbing of Scotchbond Universal inside entire prep, lightly air dry and cure 10 seconds
• Fill one prep entirely and finish curing*
• Firmly burnish adjacent band against that new composite wall in a lateral fashion
• Fill next prep and finish curing
• Remove retainer, then wedges
• Tease bands away from line angles and newly formed marginal ridges
• Tip: Pass floss between bands, then between band and new composite; this will help so much with removal of any type of band
• Remove bands with curved hemostat
• Trim mild flash at line angles and marginal ridges first at slow speed with Brasseler ET burs without water to see better (a helpful personal choice)

*Fill techniques:

• Place a small amount of flowable composite into the prep, do not cure
• Place composite incrementally in football or cigar shapes made by your assistant (thank you, Diana and Romina)
• Key: Work in small batches and burnish the composite against the line angles first to ensure the hardest aspects of the prep are without voids, down and laterally; as the material moves from under the burnisher, fold it back and condense again
• Cure and repeat until finished

With the advent of the newer bulk fill composites, you can feel comfortable filling boxes as much as 4 to 5 mm at a time and cure. I have employed this material and love the results, which don’t compromise contour or contact tightness.

The key to consistent firm “kissing contacts” is understanding all steps matter, but some more than others:

• Ensuring a seal by the wedges and the retainer
• Only light burnishing before starting
• Firm burnish against the new composite in a lateral fashion
• Once all cured, tease away bands and employ floss to loosen or release the bands
• And remember to give them the best possible occlusal contacts, as well – such as a cusp tip to a flat receiving area and no occlusal contacts on slopes or inclines

This is just one way to achieve consistent success re-establishing contours and contacts restoring multiple adjacent marginal ridges. With so many gifted clinicians offering great insight within our online content, notably on the clinician-only Spear Talk forum, you can ask for even further tips and tricks when dealing with those challenging “kissing contacts.”

I hope this article added a tool or two to your ever growing “toolbox.”

A very special thanks to my amazing assistant (lab tech, admin, everything) Diana Castillo for the images in this article.

David St. Ledger, D.D.S., is a Spear Visiting Faculty member, moderator and contributing author.