Active compounds from cinnamon can apparently be incorporated into bone substitute materials and alter their surface characteristics. This was the finding reported by Dr. drg. Anne Handrini Dewi, M.Kes., together with a research team from the Department of Biomedical Dentistry, Faculty of Dentistry, Universitas Gadjah Mada, in a study published in the International Journal of Technology in 2020. The study examined how cinnamaldehyde, the aromatic compound responsible for cinnamon’s distinctive aroma, affects the surface properties of a composite material based on plaster of Paris (POP) and calcium carbonate (CaCO₃), designed as a bone substitute for surgical procedures. The research was conducted in the FKG UGM laboratory in Yogyakarta, with the aim of determining whether the addition of cinnamaldehyde alters the topography, contact angle, and surface roughness of the material.
The Long-Standing Problem Behind Bone Surgery
When a patient undergoes surgery to repair bone damage, surgeons often need a filler material to fill the gap left by damaged bone tissue. One material that has long been used is calcium sulfate, more commonly known as plaster of Paris (POP). This material can be resorbed by the body and support bone regeneration. However, it has one major drawback: POP is absorbed by the body too quickly, preventing it from forming a sufficiently strong three-dimensional framework to support new bone growth.
A solution previously developed by the UGM research team was to combine POP with a calcium carbonate (CaCO₃) hydrogel, which is more durable and osteoconductive, meaning that it can guide the growth of new bone cells. However, another challenge arises: any material implanted into the body has the potential to trigger an inflammatory response, which is the body's natural reaction to a foreign object. Excessive inflammation can instead interfere with healing.
This is where cinnamaldehyde enters the picture as a potential solution. The compound is known as a natural anti-inflammatory and antimicrobial agent. The question is: does adding this compound to a POP-CaCO₃ composite significantly alter the material’s surface properties? And if so, is the change beneficial or detrimental?
The Surface That Determines an Implant’s Fate
Before addressing the question of inflammation, the study first addressed a more fundamental question: how do the surface properties of the material change after cinnamaldehyde is added?
This is not a trivial question. When an implant is placed inside the body, the first event is not cell attachment to the material. Instead, blood proteins immediately interact with the implant surface. This protein adsorption process determines how the body's cells subsequently respond—whether they will attach, proliferate, and form new tissue, or instead trigger a rejection response.
The research team prepared three types of specimens: pure POP, POP with 25% CaCO₃ hydrogel containing cinnamaldehyde (POP/HCin-075), and POP with 50% CaCO₃ hydrogel containing cinnamaldehyde (POP/HCin-050). The three specimens were then analyzed using scanning electron microscopy (SEM) to examine surface topography, contact-angle measurements to assess hydrophilicity, and a surface roughness tester.
The results were quite interesting. Pure POP absorbed water droplets so quickly that its contact angle could not be measured at all. Meanwhile, both cinnamaldehyde-containing composites showed contact angles below 90 degrees, meaning that they were hydrophilic, or water-friendly. POP/HCin-075 was slightly more hydrophilic (76.60°) than POP/HCin-050 (85.50°), although this difference was not statistically significant.
Surface roughness also increased substantially following the addition of the cinnamaldehyde hydrogel. Pure POP had a roughness of only 1.216 µm, whereas both composites reached approximately 13.80–14.06 µm. According to the researchers, this rougher surface was actually beneficial because it increased the porosity required for cells to grow and develop.
Cinnamon and Surface Science
The increase in contact angle following the addition of cinnamaldehyde is consistent with the compound’s natural properties. As an essential oil, cinnamaldehyde is hydrophobic, meaning that it tends to repel water. When incorporated into a hydrogel system, this property slightly reduces the ability of the material’s surface to interact with water, although not enough to make it completely hydrophobic.
“The addition of cinnamaldehyde to the hydrogel system increased the contact angle, but it remained below 90 degrees, indicating that the material was still hydrophilic and had the potential to support bone formation,” the researchers wrote in the study’s conclusion.
Hydrophilicity is important because water-friendly surfaces interact more readily with blood proteins and cells, thereby supporting the healing process. Meanwhile, micro-roughness on the material surface has been shown to stimulate macrophages, or immune cells, to release greater amounts of anti-inflammatory cytokines. The combination of hydrophilicity and surface roughness creates favorable conditions for bone regeneration.
The Next Step: From the Laboratory to a Living Body
This study is part of a long series of studies conducted by the FKG UGM team for more than a decade. After demonstrating that cinnamaldehyde can be integrated into a POP-CaCO₃ composite without compromising the material’s hydrophilic properties, the researchers stated that the next steps would include in vitro cytotoxicity testing and in vivo animal studies.
This means that the material still has a long journey ahead before it can be used clinically. Nevertheless, its scientific foundation is becoming stronger. The idea that a natural compound from a common kitchen spice could become an active component of future bone implants is no longer merely speculative; it is now a hypothesis supported by experimental data.
Authors: Achmad Zam Zam Aghasy, DDS, M.Kes.; Hazra Alifia Muharam
Photo: Pixabay
DOI Source: https://doi.org/10.14716/ijtech.v11i5.4313