Hydroxylapatite-based wrinkle fillers

Some of the advantages of hydroxylapatite-based cosmetic fillers are similar to those of non-animal stabilized hyaluronic acid gel. Both are biocompatible and do not require allergy testing prior to use; both are not derived from human or animal tissue, which minimizes the risk of contamination with pathogens.

Hydroxylapatite-based cosmetic fillers are biodegradable (i.e. they slowly disintegrate after injection) but they last relatively long (about 12 - 18 month), which is more than collagen-based fillers (3-6 mo) or hyaluronic acid-based fillers (6 - 12 month). Therefore, fewer treatments are generally required to maintain results. If the injections of a hydroxylapatite filler have created any unacceptable irregularities, they tend to eventually dissipate on their own, even though it may take a relatively long time (longer than for most other biodegradable fillers).

Hydroxylapatite-based filles appear to stimulate the production of the body's own collagen at the injection site, which may partly explain why a lesser volume of hydroxylapatite-based filler seem to equal or exceed the effects of a greater volume of other biodegradable fillers. In one study conducted in Germany and Spain, researchers compared hydroxylapatite-based filler Radiesse with a leading hyaluronic acid-based filler Restylane. It was reported that "although requiring approximately 33% less injection volume, the calcium hydroxyapatite product yielded significantly increased aesthetic improvement vs hyaluronic acid in 63% of patients at 6 months. Only 4% of patients achieved better results with hyaluronic acid; 33% achieved equal improvement with both agents." More independent comparison studies are needed to put this result in perspective.

Disadvantages

While relatively long lasting, hydroxylapatite-based fillers do degrade and have to be re-injected every year or so to maintain results.

A short-lived inflammation and/or swelling at the injection site is relatively common. It usually resolves on its own in a day or two. Chronic allergic, inflammatory or other reactions seem to be very rare - at least as rare as with other common biocompatible filler/implant materials.

Occasionally, a hydroxylapatite-based filler injection may create a bump or an irregularity under the skin (as most other fillers might do). This is often a result of improper filler selection, incorrect dose or insufficient experience of the administering practitioner. In such a situation, hydroxylapatite-based filler is at a disadvantage compared to a hyaluronic acid-based filler. Correcting the result of hydroxylapatite injection will generally require a long wait or an invasive intervention. On the other hand, misapplication of hyaluronic acid-based filler can often be corrected by injecting hyaluronidase, an enzyme that breaks down hyaluronic acid.

Considering that the results of misapplication of a hydroxylapatite filler may be long lasting, make sure to find a board certified physician who has performed at least a few hundreds of injections of this type.

Costs

Radiesse costs from $650 to $800 per syringe. It usually takes 1-2 syringes per treatment. The cost per unit volume is higher than for most other biodegradable filler. However, since Radiesse last longer and a smaller amount of it may be required for an equivalent effect, the total cost over time may actually be less that for alternative biodegradable fillers, such as Restylane or Juvederm.

Bottom line

For certain types of deep wrinkles and folds, injectable filler may be the only viable alternative short of surgery. While no filler is ideal, hydroxylapatite-based fillers appear to be among reasonably good options for problems like deep wrinkles, folds and facial fat loss. They have a somewhat different balance of durability and reversibility (i.e. more durable but less rapidly reversible) than other biodegradable fillers and represent a distinct option in the spectrum of available dermal fillers. Some people will find them a good fit for their requirements.

Hydroxylapatite microspheres (Radiesse)