Bisphosphonates adversely affect orthodontic treatment

Bisphosphonates are drugs used to increase bone density by killing off the cells that resorb old bone (osteoclasts) to 'make room' for new bone cells. Bisphosphonates include alendronate (Fosamax and Binosto), zoledronic acid (Reclast), risedronate (Actonel) and ibandronate (Boniva). Over time the failure to clear decrepit bone results in greater density but less resilience, so it comes as no surprise that bisphosphanates used for osteoporosis or cancer chemotherapy can increase the risk of fracture over time, and the troubling condition called osteonecrosis (death of bone cells) in the jaws that is resistant to treatment. A study just published in the American Journal of Orthodontics & Dentofacial Orthopedics documents adverse effects of bisphosphonates on orthodontic outcomes. The authors state:

"Bisphosphonates are a class of drugs commonly prescribed to treat osteoporosis. They act by decreasing the resorption of bone. Since tooth movement depends on bone remodeling, these drugs can impact orthodontic treatment. The purpose of this study was to evaluate the extent to which bisphosphonate therapy is a risk factor for poor orthodontic outcomes."

Orthodontists performed case reviews of women over age 50 who were treated from 2002 through 2008. They compared women who used bisphosphonates with those who never did, and assessed them for treatment time, osteonecrosis of the jaws, incisor alignment, incomplete space closure, and root parallelism (alignment). The results showed that bisphosphonates and orthodontic treatment are not a good mix:

"The records for 20 subjects with bisphosphonate exposure were collected, as well as records for 93 subjects without bisphosphonate exposure. In patients undergoing extractions, treatment times were significantly longer if they had a history of bisphosphonate use. No occurrences of osteonecrosis of the jaws were reported, nor did patients end treatment with incisor alignment discrepancies greater than 1 mm, regardless of bisphosphonate exposure. Among patients with extractions or initial spacing, there were higher odds of incomplete space closure and poor root parallelism at the end of treatment for patients using bisphosphonates."

Clinicians who manage prevention and treatment of osteopenia and osteoporosis should also bear in mind that these are not calcium deficiency disorders. The key issue to maintain the protein matrix of the bone to which the minerals attach. This protein 'scaffolding' imparts the necessary resilience and elasticity to resist fracture. It's no wonder that after several years on bisphosphonates bone can be dense but more brittle. How do we maintain the protein matrix of bone? While ancillary factors such as vitamin D, vitamin K and others should be considered, managing chronic inflammation and anabolic hormone signaling dominant. The authors conclude:

"Bisphosphonate use is associated with longer treatment times among extraction patients, increased odds of poor space closure, and increased odds of poor root parallelism."