If you still have another tooth further back on the same side, then a bridge (fixed partial denture) is still possible. What you need to know is that the longer the span of the bridge, the weaker it is. Usually a 4-unit bridge, which replaces 2 missing teeth in between, is about as long as we really should go. The reason is that even though the bridge is made with a rigid metal framework with porcelain backed on top to make it cosmetic, when you bite down in the middle (where there is no root support), the framework can still bend ever so slightly. When this occurs, it puts pressure on the ends of the bridge, where the supporting 2 teeth are and can sometimes cause the cement
to slowly break loose. Over time, a small gap may form and saliva and leakage occurs. The longer a bridge, the greater the flexure.
Now, as to address the issue of grapenuts cereal. Although I wouldn't go as far as blaming the cereal as the sole cause of any breakdown, it is comprised of many small, crunchy, hard pieces. For patient who have a lot of medium-to-large sized fillings
, and or patients with multiple root canal treated teeth, it is important to be mindful of biting into hard foods.
With regards XXXXX XXXXX with large fillings, the way I explain to my patient is that imagine a the tooth is a porcelain bowl, and the filling itself would be if we had poured concrete into this bowl. So for the most part, this now bowl of concrete is rather strong! However, if you clench down on very hard objects, the forces are transferred through the concrete and transferred onto the porcelain bowl itself. Eventually, due to constant wear & tear, stress fracture can and will occur within the bowl, even if the concrete still appear to be strong and intact. It is also possible where if you bite down on the wrong angle, instead of the hard object hitting the concrete, you now hit the edge of the bowl, where the porcelain is. Biting down with the same hard pressure, the porcelain is much more fragile than the concrete, and a piece of the bowl cracks and breaks off.
So in the mouth, a renegade grapenut piece might catch the cusp
surrounding a medium filling, the cusp being the porcelain bowl, is now more fragile and breaks off.
With regards XXXXX XXXXX that have been root canal treated, they are almost always restored with a crown especially if they're a molar
tooth. We tell the patients that doing so is part of the "standard of care" because the crown will protect the root canal treated tooth. While this is very true, I feel that some of my colleagues may unintentionally neglect to explain to their patients that even though the tooth has been crowned/capped, we still need to worry about the underlying tooth structure.
What root canal treatment does is essentially kill off the tooth; the nerve and blood supply, which carried the nutrients as well as moisturize the tooth are both removed completely and sealed off. The only reason the dead tooth stays in the mouth is due to the healthy bone and gum tissue surrounding it. So over time, the root/tooth itself starts to dry out from within, and the root actually becomes more and more brittle, easier to crack, split, and shatter over time.
And even though we have a nice, beautiful solid crown covering the root, if enough pressure is applied downwards, again, we can induce stress fractures and actually split the walls of the root. When this occurs, saliva and "crevicular fluid" can carry some oral bacteria down into the cracks, leak into the root canal, and subsequently cause a new infection leading to the failed root canal.
Although you've already lost at least 1 previous tooth, and the prognosis of this current tooth is unknown, I wanted to inform you of the dangers of eating crunchy, hard foods. Nut lovers who enjoy eating almonds, or those who may love eating Cornuts, and for you, who enjoy eating Grapenuts cereal, will need to be more mindful of where you bite down. If you have additional teeth in your mouth that have large fillings, or root-canal-treated teeth, you'll want to avoid biting down on hard objects with those teeth.
I am certainly not telling you stop eating your favorite cereal. I just hope with the information provided, we can help prevent additional, unnecessary breakdown of those teeth.
I hope my explanation of why teeth with large fillings and root canal treatments are weaker made some sense and increased your awareness slightly.
I wish you the very best,
JulXXXXX XXXXX, DDS