Cracks in Teeth, General Updates

12 Month Recall on Lower Molar with J-Shaped Lucency

It’s important to confirm the presence or absence of a crack in these teeth before consigning them to extraction. There was no obvious crack or periodontal probing. The lucency was endodontic in origin only.

Pre-op. J-shaped lucency and draining sinus present.

Pre-op. J-shaped lucency and draining sinus present.

Post-op. 4 weeks with calcium hydroxide and the sinus tract closed.

Post-op. 4 weeks with calcium hydroxide and the sinus tract closed.

12 month recall.

12 month recall.

In this case the radiographic image was typical of a root fracture. However without confirming a fracture visually, the radiographic image alone is insufficient to decide a prognosis for the tooth.

Cracks in Teeth

Is it Really a Vertical Root Fracture?

OK, we’re going to get a bit technical here and explain the difference between the commonly confused vertical root fracture and cracked tooth. Dentists like to be specific, and an accurate diagnosis will assist in determining appropriate treatment.

The reference for this is the American Association of Endodontics publication, “Cracking the Cracked Tooth Code: Detection and Treatment of Various Longitudinal Tooth Fractures”

A tooth with a crack that starts in the crown of the tooth and extends towards the apex is considered to be a cracked tooth. Further progression of the crack to the apex, resulting in separation of the crack is defined as a split tooth.

Endospot cracked tooth

The Cracked Tooth on the left, progressing to Split Tooth on the right. We see this in virgin teeth, restored teeth and endodontically treated teeth.

When we discuss a vertical root fracture, VRF, we are talking about a crack that starts in the root of the tooth. It doesn’t have to start at the apex. Mostly, VRF are associated with previously root filled teeth.

Vertical Root Fracture

The Vertical Root Fracture – a different presentation to the Cracked Tooth. This is more common in endodontically treated teeth than in teeth that have had no endodontic treatment.

So there you have it. No more incorrect diagnoses. Go here for more on how to diagnose cracked teeth.

Clinical Tips, Cracks in Teeth, Endodontic Radiography

Now you see it, now you don’t

Sometimes in endodontics, we miss signs, symptoms or findings that are important to diagnosis or prognosis. Sometimes our brain fools us into thinking we see or find things that aren’t really present. This case is a good example of both of these possible errors. The patient presented complaining of mild tenderness to bite on the 26. The tooth was slightly tender to percussion, mobility was normal and there was slight tenderness to palpation on the palatal aspect. Periodontal probing was within normal limits. Here are the intra-oral radiographs:

Bitewing cracked tooth

PA - Cracked toothCracked tooth PA

I decided to take a CBVT scan. The main finding on the scan was a lucency at the mesiopalatal aspect of the marginal tissues.

CBVT_Crack1

CBVT_Crack3

CBVT_Crack2

My plan was now to raise a flap to investigate. Once LA had been applied I probed again. This time I found a narrow deep pocket at the mesiopalatal aspect of the tooth. The locating of a pocket after giving LA that had not been found prior to LA is something that happens in my practice on an occasional, but recurring basis. In fact, it’s been happening since one of my demonstrators made me look silly during my endo specialty program by finding a pocket that I said was never there. I think there are a couple of factors behind this:

1. We are happy to probe more firmly when the patient is numb;

2. Radiographic findings, especially on CBVT point you to a specific location to probe for a pocket.

In a case such as this, the symptoms, followed by the radiographic finding increases the probability of a fracture being present. The added finding of a deep, narrow pocket increases the probability even more. That said, the fracture is not confirmed until visualised. So, a flap was raised and the root surface stained with methylene blue. The visualised crack confirmed the diagnosis.

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The CBVT helped immensely in this case. However, it’s easy to look at the CBVT and think, “Ah, I see the crack!” (go back to the bottom CBVT image above and look again),  but also have a look around the rest of the teeth shown in the CBVT. Almost all of them seem to have lucent lines running through them that look like”cracks”. It is very dangerous to look at the lucent line on a CBVT and “diagnose” a crack. All we have in this case from the CBVT is a finding that may be typical of a pattern of bone loss associated with a crack. It added to the other findings to lead to the final confirmation of the diagnosis of cracked tooth via visual inspection.

Let me know your thoughts on this in the comments section below.

Pat Caldwell