Using the CTX test as a guide to bone surgery has been controversial. What is the current thinking on the validity of this test? I have a patient with a CTX value of 66 and peri-implantitis. She needs surgical care but I don’t think that will be possible with this CTX value. Thoughts?
About CTx (from https://www.mayocliniclabs.com/): Human bone is continuously remodeled through a process of bone formation and resorption. Approximately 90% of the organic matrix of bone is type I collagen, a helical protein that is crosslinked at the N- and C-terminal ends of the molecule. During bone resorption, osteoclasts secrete a mixture of acid and neutral proteases that degrade the collagen fibrils into molecular fragments including C-terminal telopeptide (CTx). As bone ages, the alpha form of aspartic acid present in CTx converts to the beta form. Beta-CTx is released into the bloodstream during bone resorption and serves as a specific marker for the degradation of mature type I collagen. Elevated serum concentrations of beta-CTx have been reported in patients with increased bone resorption...Elevated levels of beta-C-terminal telopeptide (CTx) indicate increased bone resorption. Increased levels are associated with osteoporosis, osteopenia, Paget disease, hyperthyroidism, and hyperparathyroidism. In patients taking antiresorptive agents (bisphosphonates or hormone replacement therapy), a decrease of 25% or more from baseline beta-CTx levels (ie, prior to the start of therapy) 3 to 6 months after initiation of therapy indicates an adequate therapeutic response.
Dr. Sam comments:
Very interesting question. I'm not sure what you mean by controversial per se, as I think recent studies have shown that Ctx is not all that helpful.
See: Value of pre-operative CTX serum levels in the prediction of medication-related osteonecrosis of the jaw (MRONJ): a retrospective clinical study. EPMA J. 2019 Jan 24;10(1):21-29. doi: 10.1007/s13167-019-0160-3. eCollection 2019 Mar.
> Serum levels of CTX by itself are not reliable as a predictive or preventive measure for such complications.
Also this: Is serum C-terminal telopeptide cross-link of type 1 collagen a reliable parameter for predicting the risk of medication-related osteonecrosis of the jaws? A systematic review and meta-analysis of diagnostic test accuracy. Clin Oral Investig
. 2022 Mar;26(3):2371-2382. doi: 10.1007/s00784-022-04383-3. Epub 2022 Feb 6.
> sCTX should not be considered a reliable preoperative marker to predict MRONJ development.
Francis Serio comments:
Dr. Sam, Many thanks for this detailed response. Is there any other test/way to estimate the potential for MRONJ after extraction, bone exposure due to flap elevation, etc.
Dr. Sam comments:
@francisserio I believe panoramic radiographs can be analyzed for signs. An Oral and maxillofacial radiologist should be consulted for potentially high risk cases. I don't think a CTx test is useless, btw. It's just that using just a CTx test alone, doesn't seem to offer any predictive value based on recent studies.
However, see: Do various imaging modalities provide potential early detection and diagnosis of medication-related osteonecrosis of the jaw? A review. Dentomaxillofac Radiol
. 2021 Sep 1;50(6):20200417. doi: 10.1259/dmfr.20200417. Epub 2021 Jan 15.
> “Currently, no clear diagnostic criteria exist to assess MRONJ, and the definitive diagnosis solely relies on clinical bone exposure…Currently, MRONJ-specific imaging features cannot be firmly established. However, the current data are valuable as it may lead to a more efficient diagnostic procedure along with a more suitable selection of imaging modalities.”
Thanks for the comments. I think we can close this.