CARIES DETECTOR TO REVEAL CARIES - Peter Walford Dentistry

CARIES DETECTOR TO REVEAL CARIESCLINICAL VALUE OF CARIES DETECTOR

Caries detector lives up to its claims and is essential to today’s top quality composite restorations. That said, this page highlights the opportunity for further development in decay removal, and criticizes Academia for obfuscation and failed leadership in this area. Read on.

What is it? Caries detector is an acidophilic dye that is absorbed by acidified carious structure. Most detectors are red, formulated from 2% Acid Red 52 ( a food dye) in propylene glycol (a comestible long chain alcohol). Other dyes are available for operators who have red color-blindness; they are green, blue and black . All have no effect on bond strength.

Does it affect bonding? Studies have shown no reduction in bond strength. See EL-HOUSSEINY AND JAMJOUM, J CLIN PEDIAT DENT 2000, KAZEMI ET AL, OPER DENT 2002

How widely is Caries Detector used ? Only 15% of dentists use caries detector. The majority, 85%, don’t. It has been on the market for over 30 years- an entire generation. It makes decay removal faster, more thorough, and more definitive. Why in the world has there been such low uptake of this advance? Who or what blocked its universal adoption? Academia is my answer,as you will see in the discussion below.

Why does it reveal caries? It is known that caries is a dissolution of tooth structure by the acid metabolism of bacterial plaque. So carious tooth structure is acid. If this dye tints acidified dentin reliably, which it does, then detector makes complete removal absolutely possible to confirm.It is ,basically, liquid litmus paper. So all dentists would want a detector to do their job better, right? Caries is soft and rotten and won’t carry a load like healthy dentin.

If we want the strongest possible restorations we want 100% caries removal. Isn’t that an obvious benefit? No more guessing, relying on tactile cues, how it feels to a bur, to a spoon excavator, to an explorer. Simple paradigm, if it is red, remove it!

Why has this product not become a consensus product? If human teeth had no pulp, it would have been easy. Just keep excavating until everything is white.

But no,we do have a pulp, and the fear of entering it, and/or excessively encroaching upon it and causing harm has caused a phobic cringing from clearly identifying caries. Removing deep decay is a high-stakes game and always will be, being the gateway to root canal treatment and other escalations in treatment cost and complexity. Excruciating pain is also a possible sequel.

In the amalgam paradigm, deep decay hovering on the edge of exposure was often called “Doubtful Dentin”. Treatment consisted of covering the deepest portion with calcium hydroxide liner, covering that with IRM or other high-strength zinc-oxide (ZOE) base to ideal depth, and restoring with amalgam. The thnig to note is that all these materials are bacteriostatic. Caries could be entombed and would cease to live. In the pragmatic universe of amalgam, we could retain doubtful dentin and the pulp could still recover.

Then along came resins. Calcium hydroxide could still be used, but ZOE was off the table, because resins do not set correctly in contact with fresh ZOE. Critically, as well, composite resins have no bacteriostatic properties. So our method lost two out of three traditional cariostatic materials. Entombed bacteria under resin could continue to live in a facultatively anerobic environment.

Fortunately, Caries Detector emerged in the 1990s as composite adhesives made posterior resin restorations possible. This helped clinicians to become more definitive in caries removal.

Academia, which as scientific institutions should help clinicians become scientific and secure in the face of changed paradigms and material changes, looked at caries detector, and decided not to accept it .. Because…the dye tinted two things:

Frank, utterly demineralized fully decayed dentin.This they called “Infected Dentin”
Pre-caries, i.e., partially decayed dentin, which was found to be acidified, demineralized, but without bacterial content. This was titled, “Affected Dentin”.

Academics were concerned about the following issue: in the hands of undergraduates, more pulps could be exposed if they removed all the tinted dentin. Hence, a very small number of publications warning of the “False Positives” inherent in caries detector became the departure point for a whole generation of hand-wringing, finger-wagging and stagnation.

Academia confounded the issue first by its languaging: detector-stained dentin was called “Affected” or “Infected”, depending on its bacterial load. This is a useless distinction. The terms are confusing, not clarifying.You cannot see bacteria, so you cannot see “Infected Dentin”.

The obvious clinical need at that point was to develop another detector, one which discloses bacteria in residual “Infected Dentin” but not microbe-free”Affected Dentin”! If that had ensued, we could potentially have ensured that our restorations were not built on bacteria. But such an invention never emerged. The debate stalled at Caries Detector.

Clinicians were left with an unresolved dilemma: we are looking at pink dentin. It’s harder than the mushy caries, but this “Affected Dentin” isn’t normal dentin. Anything staining red is affected in some way, Sir, red is not the color of normal dentin.

Even if there was a way to eliminate bacterial contamination- frank caries- from the equation- we still must deal with red dentin that is acidified to an unknown extent. Red dentin is structurally inferior, uncertain in bond strength, and at the clinical level, a compromised substrate. White dentin isn’t “Affected”.. White dentin is a pure substrate. Pink is…well, dunno…

“Soft Red” and “Hard Red” would have been a more useful distinction, because that is what one experiences clinically. Soft dentin is not structural and is not a benefit to retain. It is frank caries, remove it, don’t give it a second thought.The semi-hard remaining lesion still stains pink, what do we do with it? That’s where the academic tiptoe dance came in to stranglehold the profession.

Academia has its favorite word, “Maybe”. It appears they also enjoy other derivatives of uncertainty. I suppose it gives them authority. They can purport to see the invisible like Priests or Shamans perhaps…Clinician’s don’t want uncertainty or Shamanic science. We have to act decisively. In the list below, an academic is speaking…notice how one drifts further and further away from treatment certainty……and notice how you respond to it.

Maybe some “Affected Dentin” should be retained because you might expose the pulp???(anxious moment).
Maybe just cover it with some calcigenic capping agent and it may work (uncertainty)
Maybe it will remineralize with constituents delivered to the interface by the dentinal tubules… (anxious moment)
Maybe the pulp has the recuperative power to do so or not (uncertainty)…
Maybe the subadjacent odontoblasts are still healthy enough to remineralize or possibly not?…(anxious moment)
Maybe the bacterial contamination remaining in the tubules will overwhelm the pulp’s recuperative powers (anxious moment)…
Maybe the tubules are full of smear layer and actually have no effective communication with the calcification agent and therefore it will not be not effective (anxious moment)….
Maybe a pulp horn is located under the pink “Affected Dentin” and if we go that little bit further we will expose it (anxious moment)….
Maybe if we don’t go further and leave too much the bacteria they may become facultatively anerobic and continue their nasty work (anxious moment)….

That’s the troubling thought process that academia abandoned to clinicians….. They knew traditionally that “dubious dentin” could be left in place under amalgam and and it mostly worked with the materials of the day because everything placed over it was bacteriostatic.

But the resin paradigm has different properties. Rather than aim for solutions for the new set of problems, Academia emphasized the ambiguity of red dentin, dithered about clinical anxieties, and left clinicians waffling in the dark. For 30 years they wasted a technically sound advancement to clearly identify abnormal dentin that is either completely or partially decayed. They did not drive the profession forward into the new and higher standard of care required in resin dentistry, and the need for better means of decay identification. It is not that Caries Detector falsely indicates sound normal dentin. It is always right about the pH of the dentin.

In practice, between the overlying uncertainty of “Affected Dentin” and the underlying uncertainty of the pulpal condition, clinical dentistry was left adrift ignoring the significant advancement of caries detector. Users of caries detector knew, with a whole other sensory medium- sight- what before was only perceived by touch. It wasn’t perfect. Where was leadership to innovate past its limitations?

Academia didn’t just kill the idea of identifying pre-caries clearly. It also killed the next innovations which should be obvious from the above discussion:

how to identify if bacteria still remain
how to determine how much acidified dentin to remove
how to best treat acidified “Affected” Pre-caries/Doubtful Dentin in the composite paradigm

Academia instead concluded their debate by advising- Lads, don’t use Caries Detector, there may be “False Positives”. Better to know nothing than to know more than you used to, and have to face the next level of uncertainty once frank caries is gone. Hey, you are going to have to guess about treatment unknowns in the final analysis anyway ! Stick your head in the sand, tactile was good enough in the 1890s!

Thus, I hold Academia responsible for the paltry 15% uptake of this beneficial new product, and for leaving the dental profession mired in the horse-drawn age in terms of decay removal.

So what is the clinical benefit of Caries Detector? You have more information than before! You can guess better with Caries Detector! That’s the whole point! Reduce the volume of “Pre-Caries” – to a minimum! Let excavation be guided by a new benchmark! Use Caries Detector to improve your effectiveness with deep decay removal and learn from your treatment experience in an improved decay-removal world. Give the pulp the least remineralizing and disinfecting work to do. Give your restoration the best structural foundation, give the pulp a new suite of health-promoting protocols and treatment, and give your conscience the satisfaction of having done a difficult job one step better.

How about the hope of hybridizing “Affected Dentin”? Is it real? We know that our bonding process enters the dentin to a maximum depth of 30 microns, and more commonly to less than 10 microns. If we are to retain affected dentin, it must be thinned to less than 30 microns or else it is not bonded and not cohesive with the overlying restoration. So, hybridizing thick, weakened dentin generates a structurally deficient restoration. Bad idea.

Beyond this structural issue, how do we optimize pulpal health, recovery, and remineralization?Academia leaves us without logical criteria for treating red, “Affected Dentin”.

Do we remove the smear layer?
How do we remove the smear layer?
Do we disinfect ?
How best to disinfect?
Which disinfectants harm the pulp, which don’t?
Which disinfectants reduce bond strength?
Which pulp capping agents to use?
Which pulp capping agents work best at the cellular level?
What proof is there in claims for efficacy of competing pulp capping/basing families?
Which ones work pragmatically in the clinic?
How beneficial is it to prescribe systemic anti-inflammatories immediately post-op?
What are the limits to hybridizing pre-caries with our bonding process as we restore?

These questions never go away. They need to be met with fresh eyes, fresh protocols and fresh materials to meet the perennial clinical goal – to maintain the health of the pulp, minimize pulpal inflammation, and control post-operative inflammation. Caries detector cannot make those judgement calls for you, but, at the moment, it provides the best information to prepare the best field for pulpal recovery, and is a powerful supplement to traditional tactile and visual cues with many collateral benefits.

Caries Detector to reveal caries
Caries Detector to reveal flash and surface flaws
Caries Detector to show the presence of plaque and bioburden , viz., the same role as conventional Plaque Disclosing Agent.
Caries detector to reveal debris in line and point angles in preps.
Detection of decay in preparing crown margins when field control is poor.
Engaging pedodontic patients as a “show and tell” during treatment of interproximal caries; an intraoral camera is beneficial
Preparing patients with grossly decayed teeth for possible root canal and crown treatment at first opening, confirming what has already been discussed on x-ray.

As a rural general practitioner, I should not be having to write this page. I am deeply disappointed by the intellectual irrelevance of academia, and their abdication of engagement in clinical method. There should be teams of well-funded and well-equipped researchers progressing to nail these thorny issues squarely on the head, for the benefit of society and all the motivated, capable, and well-intentioned clinicians willing to do the very best on a critical mission: one of the dental profession’s cornerstones; competent removal of decay at the clinical level, and also at the cellular level, perpetuation of the health of the living pulp.

CARIES DETECTOR IN ACTION

Where is it particularly helpful? At the DEJ, the dentin known as Mantle Dentin is less mineralized than elsewhere. The anatomical function of Mantle Dentin is to join the enamel, which is very stiff with a Flexural Modulus of 80GPa, to coronal dentin, which is much more elastic at a range of 12GPa to 16GPa. The flexural modulus of this boundary layer has not been measured, to my knowledge. Its function is to distribute stress within the DEJ of the natural tooth.

Caries often tracks along this less-mineralized layer and undermines the enamel, as visible in he adjacent photo. It is often not discolored, so that without Detector it can be clandestine and difficult to identify. Routine use of Detector identifies carious mantle dentin undermining cusps and gingival CEJs, increasing structural strength in the final restoration.

The second place where it is helpful is when approaching deep caries that appears close to exposing the pulp. Repeated staining allows the perimeter of the most deeply carious area to cleaned so that the near-exposure site can be approached with suitable caution. If an exposure does occur, it is obviously better to do it in a field that is 98% clear of caries rather than in a gooey mess of surrounding caries fulminating with microorganisms.

Clinical organization: How to dispense it and bring it to the mouth? In my clinic, Caries Detector is kept chairside in a 3cc syringe fitted with a 22 gauge tip. The syringe is housed vertically in a composite syringe organizer, and a plastic 50cc cup sits beneath it to accept drips without mess. I believe one reason that clinicians do not adopt caries detector is because it is so messy- the plastic dispensing bottle quickly gets a layer of detector between the bottle and its top. From there it spreads to the assistant’s gloves, the instruments, the tray, the patient’s clothing- yuck!

The above syringe with a small tip keeps the assistant’s gloves pristine.

At the outset of the procedure, detector is dispensed in one well of a four-well dispensing block. In its well we place a Voco Pele Tim #1 pellet. It carries to the preparation with cotton pliers. The pledglet is returned to the bonding block. As the caries is washed, the tips of the pliers are placed in the A/W stream so caries detector residue will not remain on the cotton pliers to potentially contaminate other steps using these pellets in the the acid etch and primer stages, in which the same cotton pliers are used.

In the first image below you can see areas of bright red prior to excavation, and in the second photo only one small portion is red and the rest is surrounded by pink. The pink areas feel hard to an spoon excavator or slow speed round bur. The red is soft. Soft is not structural and must be removed.

Bright red is always soft, demineralized, and structurally worthless. It is mushy. Must go.
Pink is a lesser extent of demineralization. It feels harder to the operator using a slow speed round bur, or a spoon excavator. As caries is a progressive disease from initial acid dissolution to complete acid dissolution, there is a continuum of mineral density. There is no real clinical correspondence to the terms infected/affected. What is the reality? -a continuum of mineral density. In this photo you see how much of the axial wall is affected and therefore the rationale for wanting to regain as much of that surface for bonding and hence creating as strong a restoration as possible.

Clinical recommendations for using caries detector.

Remove all red and pink when remote from the pulp. No pink gingival margins, no pink undermined cusp arms, no pink mantle dentin along DEJs. With impunity, cleanse these areas 100%of caries.
When in closer proximity to the pulp, accept that we must respond to what nature has created; if caries has progressed to exposure, no amount of tiptoeing will reverse that. Conversely, every bit of pink you can remove increases the likelihood of disinfection, hermetic seal, adhesive bond, obturation of dentin tubules, and asymptomatic recovery.

The path to excellence is to develop a predictable pulp cap procedure rather than to avoid excavating cavities thoroughly. See Pulpal Encroachment and Pulp Cap

Learn to deal with minimal tooth structure by developing better prep designs when tooth structure is not ideal. Learn to deal with the histological needs of pulp tissue in composite resin restoration by studying biocompatibility and adopting a biocompatible treatment protocol. See Pulp Protection and Biocompatibity

Longitudinal studies on the efficacy of leaving caries are usually only short term and based on pedodontic and young adult populations. That excludes 75% of the population. Conclusion: leaving caries in older populations is without scientific proof.

Longitudinal studies of pulp cap using MTA have large international literature support in a wide range of age groups. Post-op periods of 5 to 10 years show retained vitality and freedom from apical disease.

Despite many attempts at improving clinic-friendly upgrades it remains a devil to use- long setting time (ten minutes+), poor plasticity, and it cannot be acid-etched and rinsed because it is a very high pH substance and in conjunction with acid -either that of a total etch protocol, or that of a Self-Etch adhesive, it will undergo an acid-base reaction and disappear. Thus it must be covered with a second material that will withstand acid etching. All these frustrations requires time to manage and increase treatment cost.

Out in the trenches: what treatment protocols for deep dentin and pulp cap are being used, and do we have a consensus -supported Standard of Care?: At the time of a study by Clinician’s Report in January 2010, only 3% of practitioners surveyed were using MTA . The use of silicate-based materials has gained ground since then, but the variety of methods used in pulp cap is still probably indicative of wide variation in standards of care in managing deep caries and pup cap. See Resin Pulp Cap Materials