Bioactive Materials: Is the Future Here?
In dentistry, “bioactive” is a broad term that typically describes a type of dental material that interacts with living tissue. Calcium hydroxide was first introduced as a pulp-capping material in the 1920s, and today it is used across multiple applications in endodontics.1 Many other types of bioactive materials have come onto the scene since then, finding a variety of uses in different dental specialties.
While bioactive materials are not new to dentistry, they are commanding more attention now. What separates bioactive materials from conventional materials? How can these materials be used in different specialties today? What is the efficacy of these products? Should dentists be integrating bioactive materials into their practices — or should they wait?
Types of Bioactive Materials
One of the goals of bioactive materials is to last longer than traditional inert dental materials, such as amalgams.2 Bioactive materials are also designed to positively interact with living tissue, enhancing a dentist’s restorative and reconstructive work.2,3 Different materials work in different ways, but they can be defined by three main actions. Bioactive materials remineralize teeth, form a hydroxyapatite layer and/or regenerate live tissue, according to Fay Goldstep, DDS, FASDA, FADFE, a practicing dentist and dental consultant.3
Glass ionomers are one of the main categories of bioactive materials designed to play a role in remineralization. Glass ionomers have been on the market since the 1970s, according to Michael B. Miller, DDS, FAGD, FAACD, president of dental product review site Reality Ratings & Reviews. “They have stood the test of time and still have many current applications in restorative and pediatric dentistry and prosthodontics,” he said.
Glass ionomer cements (GICs) can be used as restorative dental materials. For example, GIC can help to preserve more of the existing tooth when treating caries that affect dentin. This bioactive material chemically bonds to teeth and releases fluoride, which helps to kill any remaining bacteria.4 Dentists are able to leave some affected dentin, preserving more of the tooth’s natural structure. Treating the same cavity with composite resin would require the removal of all affected dentin and potentially some healthy dentin.
GIC was created in 1972, and, in 1988, the first resin-modified glass ionomer (RMGI) followed.5 RMGIs can be used to release fluoride, like GICs, but this material also has a small amount of composite resin added to it to facilitate light curing.5 Additionally, a sandwich technique was developed that uses RMGI as a liner to seal the dentin and release fluoride while using a layer of resin composite to fill the remainder of the cavity.6 Products like the Giomer line from Shofu Dental and ACTIVA™ BioACTIVERESTORATIVE™ from Pulpdent are among those available today.
When they come into contact with saliva, bioactive dental materials can also facilitate the formation of hydroxyapatite crystals, which can integrate with the tooth structure and remineralize it.3 Calcium silicate and calcium aluminate materials set with an acid-base reaction and form an apatite layer on teeth.3 Products like Ceramir® by Doxa and BioRoot™ by Septodont are examples of this type of material, according to Goldstep.
Interest is high in bioactive materials because they can also play roles in regenerating tissue. Mineral trioxide aggregate (MTA) is a bioactive dental material that contains calcium and silicate.7 “MTA-type products are helping to repair perforations and seal roots through apical surgery, allowing for bone healing and a return to normal periodontal ligament [PDL] function,” explained Ross Isbell, DMD, MBA, of Isbell Dental, Gadsden, Alabama, and the AGD Impact Testing the Tools columnist. MTA was approved by the Food and Drug Administration in 1997.7
Bioactive Materials at Work With bioactive materials available for decades now, how are different dental specialties putting them to use? Bioactive materials have promising applications in preventive dentistry. For example, bioactive toothpastes can be used with the goal of remineralizing teeth and preventing caries.3 “Preventive dentistry’s use of different types of topical applications in high caries-risk patients can incorporate silver diamine fluoride or the use of toothpastes or mouth rinses to encourage uptake of calcium, phosphate, fluoride and other helpful ions to slow or stop the process of decay,” said Isbell.
The formation of hydroxyapatite crystals on the surface of the tooth structure is an exciting prospect for restorative dentistry.3 “In restorative dentistry, bioactive materials promise to seal the interface between the material and the tooth structure more tightly, meaning there will be less chance of any type of leakage leading to secondary caries, marginal staining and dislodgement,” said Miller.
Bioactive materials open the door to alternative approaches to care. “Pulp-capping materials can be used by any clinician who would like to try to prevent or hold off conventional root canal therapy. Bioactive restoratives can be used in place of conventional composites for high caries-risk patients,” said Nathaniel Lawson, DMD, PhD, director of the division of biomaterials at the University of Alabama at Birmingham School of Dentistry. MTA materials are at work in the field of endodontics.
MTA is meant to stimulate healing and osteogenesis.8 “In endodontics, bioceramic sealers aim to create a more effective seal while simultaneously promoting a healthier pH and environment in the periapical area to reduce or eliminate the presence of bacterial and inflammatory activity in the PDL space,” said Isbell.
Bioactive materials are also finding a place in implant dentistry and oral surgery. Materials that can bond implants to bone are an exciting prospect in these areas of dentistry. “In oral surgery, guided bone regeneration materials with more advanced membranes and the incorporation of regenerative factors into grafting materials are helping to create more predictable growth patterns,” said Isbell.
Product Efficacy
Bioactive materials are available for use today, and their intended applications seem like the next frontier for dentistry. Yet, these are still the early days of these advancements. “Most companies have pilot programs or internal studies that show efficacy, but there are also programs such as the National Dental Practice Based Research Network that are independently studying how well materials and processes are working,” said Isbell. The research conducted thus far shows significant promise for bioactive materials in dentistry.
Research has demonstrated that GICs and RMGIs do prevent bacterial microleakage due to the strong adhesion that occurs when ions in the restorative material and the tooth structure react with each other, and these materials also prevent caries due to the release of fluoride.5 More research is being conducted to improve both of these materials. For example, researchers are examining how the addition of bioactive glass to GIC can increase bioactivity.9 Further research could shed light on how to develop protocols for higher bonding strength using GIC and RMGI during restorations.9 The use of hydroxyapatite nanoparticles (HANPs) in dentistry is the subject of current research. Researchers have noted that the addition of HANPs can improve the quality of commonly used dental materials, but how these particles interact with the intraoral environment is not yet fully understood.10
MTA-based materials have been shown to have antibacterial properties and osteoinductive ability, but researchers have also called for longer-term, in vivo studies.11
Dentists like Miller caution that not all of the research is there yet. “Manufacturers are less likely in today’s hyper-commercialized world to wait for results,” he said. “They want to market their products now, regardless of whether their claims are validated or not. In my opinion, these companies want a return on their investments quickly, and my fear is that practicing dentists and patients may pay the price if the promised efficacy of these materials does not materialize. In vitro studies are necessary to ensure proof of concept, but randomized, long-term clinical studies are the missing link for all of these newer materials.”
Using Bioactive Materials Today
While research is ongoing, bioactive materials are widely available for use in dental practices today. “There is already movement toward regeneration and biomimetics instead of demolition and replacement of tooth structure, and I hope that trend continues,” said Isbell.
For dentists who are considering the role of bioactive materials in their practices, does it make sense to join the trend now or wait for more research to support their efficacy?
The answer depends on the individual dentist and the practice. Bioactive materials are readily available on the market, and many have been in use for decades. Integrating bioactive materials into a practice typically does not come with a steep learning curve. “The materials function very similarly to how their nonbioactive predecessors did,” said Isbell. The differences between bioactive materials and conventional materials may lie in the application process. For example, a particular type of bonding agent may be critical for the success of a bioactive restorative material, according to Miller.
“Dentists and hygienists must be educated on the advantages of bioactive materials,” said Goldstep. As dentists become educated, communicating with patients is an important step in introducing bioactive materials into a practice. While some bioactive materials, such as glass ionomers, have been in use for a long time in many practices, Lawson takes the time to talk with his patients about the materials and the intended goals of treatment.
“When I use glass ionomers in high caries-risk patients, I inform the patients that we are making compromises in esthetics and strength in order to use a material that is protective of the remaining tooth structure,” Lawson said. “When I perform a pulp cap, I inform the patient that I am doing a procedure that is meant to help prevent the need for a traditional root canal treatment. However, the tooth may not respond well, and the root canal treatment may be needed anyhow.” Clear communication helps patients understand the materials being used in their mouths and helps dentists manage patient expectations.
The financial investment is also another critical consideration for dentists contemplating the role of bioactive materials in their practices. Some dentists, like Miller, take a more conservative approach. “In today’s post-COVID-19, hyper-inflationary times, I believe clinicians need to exercise restraint from being on the bleeding edge,” he said.
Others believe that bioactive materials should be the standard of care today. “Bioactive materials are the present and future of dentistry,” said Isbell. “The ability to positively not just halt decay but sometimes even reinforce and strengthen tooth structure is a blessing that every dentist should be incorporating into their daily workflow.” Dentists can consider the promises of bioactive materials, as well as their individual comfort levels and inclinations to invest, to determine what is best for their practices now and in the future.
Carrie Pallardy is a freelance writer and editor based in Chicago. To comment on this article, email impact@agd.org.
References
1. Ba-Hattab, Raidan, et al. “Calcium Hydroxide in Endodontics: An Overview.” Open Journal of Stomatology, vol. 06, no. 12, 2016, pp. 274–289.
2. Dworkin, Olivia, et al. “What Is Bioactive Dentistry? A Review?” Dental CE Today, dentalcetoday.com/wpcontent/uploads/2018/06/DT_Dworkin_Jan_217.pdf. Accessed 27 May 2022.
3. Goldstep, Fay. “Bioactivity in Restorative Dentistry: A User’s Guide.” Oral Health Group, 10 Dec. 2019, oralhealthgroup.com/features/bioactivity-restorative-dentistry-users-guide. Accessed 27 May 2022.
4. Knight, Geoffrey M. “Glass Ionomers: Why, Where and How.” Oral Health Group, 10 Dec. 2019, oralhealthgroup.com/features/glass-ionomers-why-where-and-how. Accessed 27 May 2022.
5. Schulze, Karen, et al. “10-Year Follow-Up on Resin Modified Glass Ionomer Restorations.” Decisions in Dentistry, 12 Oct. 2020, decisionsindentistry.com/article/10-year-follow-upon-resin-modified-glass-ionomer-restorations/. Accessed 27 May 2022.
6. “Glass Ionomer Cement.” ScienceDirect, sciencedirect.com/ topics/medicine-and-dentistry/glass-ionomer-cement. Accessed 27 May 2022.
7. Parirokh, Masoud, et al. “Mineral Trioxide Aggregate and Other Bioactive Endodontic Cements: An Updated Overview–Part I: Vital Pulp Therapy.” International Endodontic Journal, vol. 51, no. 2, 2017, pp. 177–205.
8. Cervino, Gabriele, et al. “Mineral Trioxide Aggregate Applications in Endodontics: A Review.” European Journal of Dentistry, vol. 14, no. 4, 2020, pp. 683–691.
9. Park, Eun Young, and Sohee Kang. “Current Aspects and Prospects of Glass Ionomer Cements for Clinical Dentistry.” Yeungnam University Journal of Medicine, vol. 37, no. 3, 2020, pp. 169–178.
10. Balhuc, Silvia, et al. “Dental Applications of Systems Based on Hydroxyapatite Nanoparticles—An Evidence-Based Update.” Crystals, vol. 11, no. 6, 2021, p. 674.
11. Palczewska-Komsa, M., K. Kaczor-Wiankowska, and A. Nowicka. “New Bioactive Calcium Silicate Cement Mineral Trioxide Aggregate Repair High Plasticity (MTA HP)—A Systematic Review.” Materials, vol. 14, no. 16, 2021, p. 4573.
There is one Self-Instruction Exercise (No. IM141, 1 CE Credit Basic Sciences – Subject Code: 010) associated with this article.
While bioactive materials are not new to dentistry, they are commanding more attention now. What separates bioactive materials from conventional materials? How can these materials be used in different specialties today? What is the efficacy of these products? Should dentists be integrating bioactive materials into their practices — or should they wait?
Types of Bioactive Materials
One of the goals of bioactive materials is to last longer than traditional inert dental materials, such as amalgams.2 Bioactive materials are also designed to positively interact with living tissue, enhancing a dentist’s restorative and reconstructive work.2,3 Different materials work in different ways, but they can be defined by three main actions. Bioactive materials remineralize teeth, form a hydroxyapatite layer and/or regenerate live tissue, according to Fay Goldstep, DDS, FASDA, FADFE, a practicing dentist and dental consultant.3
Glass ionomers are one of the main categories of bioactive materials designed to play a role in remineralization. Glass ionomers have been on the market since the 1970s, according to Michael B. Miller, DDS, FAGD, FAACD, president of dental product review site Reality Ratings & Reviews. “They have stood the test of time and still have many current applications in restorative and pediatric dentistry and prosthodontics,” he said.
Glass ionomer cements (GICs) can be used as restorative dental materials. For example, GIC can help to preserve more of the existing tooth when treating caries that affect dentin. This bioactive material chemically bonds to teeth and releases fluoride, which helps to kill any remaining bacteria.4 Dentists are able to leave some affected dentin, preserving more of the tooth’s natural structure. Treating the same cavity with composite resin would require the removal of all affected dentin and potentially some healthy dentin.
GIC was created in 1972, and, in 1988, the first resin-modified glass ionomer (RMGI) followed.5 RMGIs can be used to release fluoride, like GICs, but this material also has a small amount of composite resin added to it to facilitate light curing.5 Additionally, a sandwich technique was developed that uses RMGI as a liner to seal the dentin and release fluoride while using a layer of resin composite to fill the remainder of the cavity.6 Products like the Giomer line from Shofu Dental and ACTIVA™ BioACTIVERESTORATIVE™ from Pulpdent are among those available today.
When they come into contact with saliva, bioactive dental materials can also facilitate the formation of hydroxyapatite crystals, which can integrate with the tooth structure and remineralize it.3 Calcium silicate and calcium aluminate materials set with an acid-base reaction and form an apatite layer on teeth.3 Products like Ceramir® by Doxa and BioRoot™ by Septodont are examples of this type of material, according to Goldstep.
Interest is high in bioactive materials because they can also play roles in regenerating tissue. Mineral trioxide aggregate (MTA) is a bioactive dental material that contains calcium and silicate.7 “MTA-type products are helping to repair perforations and seal roots through apical surgery, allowing for bone healing and a return to normal periodontal ligament [PDL] function,” explained Ross Isbell, DMD, MBA, of Isbell Dental, Gadsden, Alabama, and the AGD Impact Testing the Tools columnist. MTA was approved by the Food and Drug Administration in 1997.7
Bioactive Materials at Work With bioactive materials available for decades now, how are different dental specialties putting them to use? Bioactive materials have promising applications in preventive dentistry. For example, bioactive toothpastes can be used with the goal of remineralizing teeth and preventing caries.3 “Preventive dentistry’s use of different types of topical applications in high caries-risk patients can incorporate silver diamine fluoride or the use of toothpastes or mouth rinses to encourage uptake of calcium, phosphate, fluoride and other helpful ions to slow or stop the process of decay,” said Isbell.
The formation of hydroxyapatite crystals on the surface of the tooth structure is an exciting prospect for restorative dentistry.3 “In restorative dentistry, bioactive materials promise to seal the interface between the material and the tooth structure more tightly, meaning there will be less chance of any type of leakage leading to secondary caries, marginal staining and dislodgement,” said Miller.
Bioactive materials open the door to alternative approaches to care. “Pulp-capping materials can be used by any clinician who would like to try to prevent or hold off conventional root canal therapy. Bioactive restoratives can be used in place of conventional composites for high caries-risk patients,” said Nathaniel Lawson, DMD, PhD, director of the division of biomaterials at the University of Alabama at Birmingham School of Dentistry. MTA materials are at work in the field of endodontics.
MTA is meant to stimulate healing and osteogenesis.8 “In endodontics, bioceramic sealers aim to create a more effective seal while simultaneously promoting a healthier pH and environment in the periapical area to reduce or eliminate the presence of bacterial and inflammatory activity in the PDL space,” said Isbell.
Bioactive materials are also finding a place in implant dentistry and oral surgery. Materials that can bond implants to bone are an exciting prospect in these areas of dentistry. “In oral surgery, guided bone regeneration materials with more advanced membranes and the incorporation of regenerative factors into grafting materials are helping to create more predictable growth patterns,” said Isbell.
Product Efficacy
Bioactive materials are available for use today, and their intended applications seem like the next frontier for dentistry. Yet, these are still the early days of these advancements. “Most companies have pilot programs or internal studies that show efficacy, but there are also programs such as the National Dental Practice Based Research Network that are independently studying how well materials and processes are working,” said Isbell. The research conducted thus far shows significant promise for bioactive materials in dentistry.
Research has demonstrated that GICs and RMGIs do prevent bacterial microleakage due to the strong adhesion that occurs when ions in the restorative material and the tooth structure react with each other, and these materials also prevent caries due to the release of fluoride.5 More research is being conducted to improve both of these materials. For example, researchers are examining how the addition of bioactive glass to GIC can increase bioactivity.9 Further research could shed light on how to develop protocols for higher bonding strength using GIC and RMGI during restorations.9 The use of hydroxyapatite nanoparticles (HANPs) in dentistry is the subject of current research. Researchers have noted that the addition of HANPs can improve the quality of commonly used dental materials, but how these particles interact with the intraoral environment is not yet fully understood.10
MTA-based materials have been shown to have antibacterial properties and osteoinductive ability, but researchers have also called for longer-term, in vivo studies.11
Dentists like Miller caution that not all of the research is there yet. “Manufacturers are less likely in today’s hyper-commercialized world to wait for results,” he said. “They want to market their products now, regardless of whether their claims are validated or not. In my opinion, these companies want a return on their investments quickly, and my fear is that practicing dentists and patients may pay the price if the promised efficacy of these materials does not materialize. In vitro studies are necessary to ensure proof of concept, but randomized, long-term clinical studies are the missing link for all of these newer materials.”
Using Bioactive Materials Today
While research is ongoing, bioactive materials are widely available for use in dental practices today. “There is already movement toward regeneration and biomimetics instead of demolition and replacement of tooth structure, and I hope that trend continues,” said Isbell.
For dentists who are considering the role of bioactive materials in their practices, does it make sense to join the trend now or wait for more research to support their efficacy?
The answer depends on the individual dentist and the practice. Bioactive materials are readily available on the market, and many have been in use for decades. Integrating bioactive materials into a practice typically does not come with a steep learning curve. “The materials function very similarly to how their nonbioactive predecessors did,” said Isbell. The differences between bioactive materials and conventional materials may lie in the application process. For example, a particular type of bonding agent may be critical for the success of a bioactive restorative material, according to Miller.
“Dentists and hygienists must be educated on the advantages of bioactive materials,” said Goldstep. As dentists become educated, communicating with patients is an important step in introducing bioactive materials into a practice. While some bioactive materials, such as glass ionomers, have been in use for a long time in many practices, Lawson takes the time to talk with his patients about the materials and the intended goals of treatment.
“When I use glass ionomers in high caries-risk patients, I inform the patients that we are making compromises in esthetics and strength in order to use a material that is protective of the remaining tooth structure,” Lawson said. “When I perform a pulp cap, I inform the patient that I am doing a procedure that is meant to help prevent the need for a traditional root canal treatment. However, the tooth may not respond well, and the root canal treatment may be needed anyhow.” Clear communication helps patients understand the materials being used in their mouths and helps dentists manage patient expectations.
The financial investment is also another critical consideration for dentists contemplating the role of bioactive materials in their practices. Some dentists, like Miller, take a more conservative approach. “In today’s post-COVID-19, hyper-inflationary times, I believe clinicians need to exercise restraint from being on the bleeding edge,” he said.
Others believe that bioactive materials should be the standard of care today. “Bioactive materials are the present and future of dentistry,” said Isbell. “The ability to positively not just halt decay but sometimes even reinforce and strengthen tooth structure is a blessing that every dentist should be incorporating into their daily workflow.” Dentists can consider the promises of bioactive materials, as well as their individual comfort levels and inclinations to invest, to determine what is best for their practices now and in the future.
Carrie Pallardy is a freelance writer and editor based in Chicago. To comment on this article, email impact@agd.org.
References
1. Ba-Hattab, Raidan, et al. “Calcium Hydroxide in Endodontics: An Overview.” Open Journal of Stomatology, vol. 06, no. 12, 2016, pp. 274–289.
2. Dworkin, Olivia, et al. “What Is Bioactive Dentistry? A Review?” Dental CE Today, dentalcetoday.com/wpcontent/uploads/2018/06/DT_Dworkin_Jan_217.pdf. Accessed 27 May 2022.
3. Goldstep, Fay. “Bioactivity in Restorative Dentistry: A User’s Guide.” Oral Health Group, 10 Dec. 2019, oralhealthgroup.com/features/bioactivity-restorative-dentistry-users-guide. Accessed 27 May 2022.
4. Knight, Geoffrey M. “Glass Ionomers: Why, Where and How.” Oral Health Group, 10 Dec. 2019, oralhealthgroup.com/features/glass-ionomers-why-where-and-how. Accessed 27 May 2022.
5. Schulze, Karen, et al. “10-Year Follow-Up on Resin Modified Glass Ionomer Restorations.” Decisions in Dentistry, 12 Oct. 2020, decisionsindentistry.com/article/10-year-follow-upon-resin-modified-glass-ionomer-restorations/. Accessed 27 May 2022.
6. “Glass Ionomer Cement.” ScienceDirect, sciencedirect.com/ topics/medicine-and-dentistry/glass-ionomer-cement. Accessed 27 May 2022.
7. Parirokh, Masoud, et al. “Mineral Trioxide Aggregate and Other Bioactive Endodontic Cements: An Updated Overview–Part I: Vital Pulp Therapy.” International Endodontic Journal, vol. 51, no. 2, 2017, pp. 177–205.
8. Cervino, Gabriele, et al. “Mineral Trioxide Aggregate Applications in Endodontics: A Review.” European Journal of Dentistry, vol. 14, no. 4, 2020, pp. 683–691.
9. Park, Eun Young, and Sohee Kang. “Current Aspects and Prospects of Glass Ionomer Cements for Clinical Dentistry.” Yeungnam University Journal of Medicine, vol. 37, no. 3, 2020, pp. 169–178.
10. Balhuc, Silvia, et al. “Dental Applications of Systems Based on Hydroxyapatite Nanoparticles—An Evidence-Based Update.” Crystals, vol. 11, no. 6, 2021, p. 674.
11. Palczewska-Komsa, M., K. Kaczor-Wiankowska, and A. Nowicka. “New Bioactive Calcium Silicate Cement Mineral Trioxide Aggregate Repair High Plasticity (MTA HP)—A Systematic Review.” Materials, vol. 14, no. 16, 2021, p. 4573.
There is one Self-Instruction Exercise (No. IM141, 1 CE Credit Basic Sciences – Subject Code: 010) associated with this article.