Written by: John Tunnell, D.D.S., M.S. (Dallas County Dental Society Member)
Lately, many of my older patients have been asking me a question with surprising regularity “Will my osteoporosis affect my healing after surgery?” It’s always a difficult question to answer due to the scarcity of evidence that currently exists. Intuitively, it makes sense that osteoporosis would have an adverse effect on healing. Osteoporotic changes arise due to irregularities in bone remodeling in which “bone resorption outpaces bone formation”1, resulting in decreased bone mass and increased bone fragility and susceptibility to fracture. With bone resorption occurring at a faster rate than bone formation, how might our osteoporotic patients respond following an extraction or implant placement?
To answer these questions, researchers looked at the impact that osteoporotic changes in the periodontium have on alveolar bone healing. They utilized an ovariectomy-induced osteoporosis mouse model (the OVX group) and used micro-CT imaging, molecular/cellular assays, and histologic assessments to evaluate bone healing in these mice following tooth extraction.
The study consisted of several parts. First, they confirmed that ovariectomy did indeed produce the osteoporotic phenotype in both the long bones of the appendicular skeleton and the alveolar bone of the maxilla. Next, they found that ovariectomy induced atrophy of the periodontal ligament and subsequent reduction in the number of osteoprogenitor cells within the PDL. As osteoprogenitor cells play a vital role in bone homeostasis and healing after injury, it stands to reason that a lack of osteoprogenitor cells would have a detrimental effect on the bone healing response. Therefore, to test that reasoning, the researchers extracted the maxillary first molars of both young wild type mice and OVX mice and observed healing following extraction at different time points. In the OVX mice, they found smaller PDL’s and fewer total number of osteoprogenitor cells compared to healthy mice post-extraction. And predictably, they found that the OVX mice healed significantly slower than wild-type mice.
For the first time, this study provides a possible mechanism for impaired healing in osteoporotic mice. In the mouse model, ovariectomy-induced osteoporosis results in atrophy of the PDL, a decrease in the number of viable and available osteoprogenitor cells, and a resultant decrease in the speed of healing. While we have to be careful in extrapolating the results of an animal study to human patient care, we may at least be able to give an evidence-based answer to that question posed by so many osteoporotic patients. To sum it up, maybe we should give them just a little more time to heal.
1. Arioka M, Zhang X, Li Z, et al. Osteoporotic Changes in the Periodontium Impair Alveolar Bone Healing. J Dent Res. 2019;98(4):450-458.