GK® Amalgam Capsule: Dental Amalgam History | ATBIO
GK began with a collaboration to bring materials research into dental restoration. From silver alloy powder to predosed capsules and production equipment, the brand grew by addressing practical challenges. Today, ATBIO’s product focus is gradually shifting from amalgam capsules toward light-cured composite resins, glass ionomer cements and other materials, building on that experience in research and manufacturing.
1. Where Materials Research Met Dentistry
GK’s development began in 1984 with research into dental silver alloys. The name reflects its origins: G stands for the Central Iron & Steel Research Institute, and K for the dental hospital of Beijing Medical University, now Peking University Hospital of Stomatology. This collaboration between materials science and dentistry laid the foundation for the brand.
From 1985, Professor Wang Man’en worked with the institute to develop high-copper amalgam. Applying alloy-processing expertise to dental materials, the institute proposed rapidly cooling molten alloy on a high-speed cooling roller, then grinding, sieving and annealing it to produce silver alloy powder. A patent application followed that year (CN85100673B).
The research then moved toward a commercial product. It passed appraisal by the Ministry of Metallurgical Industry in 1985, entered trial production in 1986 and reached the market in 1987. The collaborative work received a Beijing Medical University science and technology achievement award in 1989, while GK’s early materials expertise continued to take shape.
2. From Alloy Powder to a Predosed Capsule
With the alloy powder developed, research turned to how the material could be packaged and used. Loading silver alloy powder and mercury into a capsule in predetermined proportions reduces the need for chairside weighing and proportioning. This work led to the beginnings of the GK amalgam capsule in 1988; the project passed ministry appraisal and entered China’s National Torch Programme.
Capsule development focused on how to store the powder and mercury and bring them together before use. The early design separated the components with a membrane, which a plunger ruptured in preparation for mixing (CN2032067U). Research then explored an elastic separating cap (CN2105281U). In 1994, a further design proposed packaging the alloy powder and mercury together without an internal separator (CN2239242Y). From separating the components to simplifying the capsule’s interior, each approach addressed practical questions of loading and mixing.
Powder processing continued to develop alongside capsule design. The institute investigated sintering, grinding and ageing the coarse powder retained after sieving, exploring further use of material from powder production. Filed in 1994 and granted in 2000, the resulting patent (CN1050789C) formed another part of GK’s early technical foundation.
3. Bringing Research into Manufacturing and the Market
When the Sitai business joined Advanced Technology & Materials (AT&M), dental materials research and industrial development continued within the group. In 1999, ownership of capsule patent CN2239242Y transferred from the institute to AT&M, carrying the technology forward with the business.
Annual domestic sales of GK capsules exceeded five million for the first time in 2002. Over the brand’s development, its domestic market share at one point exceeded 70%, and exports reached more than 50 countries and regions. GK capsules received CE certification on 26 March 2003. In November that year, Beijing AT&M Biomaterials Co., Ltd. was established to continue developing the dental materials business.
Research also extended beyond the material and capsule to dosing during production. In 2017, ATBIO developed a mercury-dispensing device using a fixed-volume through-hole and a reciprocating push rod to meter mercury for individual capsules. The company filed a patent application that year, with grant following in 2019 (CN108042222B). Work on alloy powders, capsule structures and production equipment progressively built experience spanning materials development and manufacturing processes.
4. From Amalgam Capsules to a New Product Focus
Dental materials have evolved alongside changing environmental requirements. Adopted in Kumamoto, Japan, in 2013, the Minamata Convention on Mercury has driven efforts to reduce mercury use and releases, supporting the transition toward mercury-free dental restoration.
In 2025, the Convention’s sixth Conference of the Parties set 2034 as the phase-out year for the manufacture, import and export of dental amalgam, while retaining an exception when a dental practitioner considers its use necessary for a patient’s needs. This established a clear global timetable for the transition. Read the provisions.
As dentistry moves toward mercury-free materials, ATBIO’s product focus is gradually shifting from amalgam capsules to light-cured composite resins, glass ionomer cements and other materials. The experience gained in materials research, structural design and manufacturing through GK amalgam capsules continues to inform product development.
Today, the GK range includes glass ionomer dental cements and VPS impression materials for luting, restoration and impression-taking. ATBIO’s materials research has also expanded into composite resins and related restorative materials under NANOFIL®.
From its beginnings in amalgam capsules, GK has grown through materials development, manufacturing and an expanding product range. As a new era in dental materials takes shape, the brand continues to develop products around dental applications.
References
CN85100673B — Manufacturing high-copper dental silver alloy powder. Application date: 1 April 1985. Explores alloy powder production using a rapid-cooling roller, followed by grinding, sieving and annealing—an early dental silver alloy powder process.
CN2032067U — Dental amalgam capsule. Application date: 21 July 1988. Uses a separating membrane and plunger to keep predosed alloy powder and mercury apart. The membrane is ruptured before use to prepare the components for mixing.
CN2105281U — A dental amalgam capsule. Application date: 5 October 1991. Uses an elastic separating cap between powder and mercury, addressing the capsule’s separation structure and vibratory mixing.
CN2239242Y — Dental amalgam capsule. Application date: 19 October 1994. Proposes packaging alloy powder and mercury together without an internal separator, exploring a simpler capsule structure.
CN1050789C — Manufacturing dental silver alloy powder. Application date: 9 June 1994. Investigates sintering, grinding and ageing coarse powder retained after sieving to make further use of powder-production material.
CN108042222B — Mercury-dispensing device for dental amalgam capsule production. Application date: 24 November 2017. Uses a fixed-volume through-hole and reciprocating rod to dispense mercury for individual capsules, addressing the dosing stage of capsule production.
Peking University Health Science Center — Professor Wang Man’en. Describes her work with the institute on high-copper amalgam and the related Beijing Medical University science and technology achievement award in 1989.
Minamata Convention on Mercury — Text and Annexes. Adopted in Kumamoto, Japan, on 10 October 2013; entered into force on 16 August 2017.
Minamata Convention Secretariat — Dental Amalgam Phase-out. Explains the 2034 phase-out year for manufacture, import and export established at COP-6, including the exception for necessary treatment based on patients’ needs.
ATBIO — Current GK Product Range. Presents glass ionomer dental cements, VPS impression materials and other current products.
ATBIO Company Archives and Company-confirmed Information. Sources for the brand name, early appraisal and production milestones, historical business figures, CE certification milestone and the shift in product focus.
About the Manufacturer
AT&M Biomaterials Co., Ltd. (ATBIO) develops, manufactures and supports dental materials. Explore the GK range for product information.
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