A patented grinding technique ensures that the ultra fine grains are also highly transparent.
Tooth decay is one of the most common ailments aﬄicting men, women and children the world over. Despite the fact that dental hygiene is constantly improving, alone in Germany, dentists fill approximately 85 million cavities annually. And patients are increasingly asking for fillings that match the color of their natural teeth. These composite tooth fillings, which consist mainly of glass powder and polymers, are quickly replacing the standard amalgam filling, which contains mercury.
For over ten years, SCHOTT has been a global quality leader in the area of ultra pure glass powder for the dental industry. ”Our special grinding technique enables us to manufacture glass powder that is very transparent, yet has extremely small grains,” said Susanne Kessler, Head of Technical Sales at SCHOTT Electronic Packaging GmbH in Landshut, Germany. Due to the high transparency of the powder from SCHOTT, the color of the filling can be determined individually by adding pigments. ”Mother nature has given humanity many shades of colors for our teeth,” she said. The fillings made from glass powder are also easy to polish, for white and shiny surfaces.
Extremely hard, yet elastic
In addition to esthetic aspects, fillings must also exhibit special properties with regards to strength. Dental enamel, which is the hardest substance found in the human body, must stand up to enormous pressure. For example, during chewing, a jaw can exert pressure of about 800 newtons per square centimeter. This is roughly the same load that a cube of sugar would exert on the ground if someone with normal weight steps onto it with his full weight.
Each grain of glass powder from SCHOTT is roughly one hundredth the thickness of a hair. This ultra fine grain enables extremely dense packing inside the respective tooth filling, giving it considerable hardness to withstand the pressure. This hard glass powder accounts for roughly 80 percent of the total weight of a filling. SCHOTT’s customers generally combine it with a special resin. This plastic portion of the filling provides suﬃcient elasticity, without which the filling would be too brittle. To ensure that the glass powder bonds well with the synthetic material, the experts at SCHOTT must first prepare it with the adhesive agent, silane. This results in a durable bonding composite that does not harden until the filling is in the tooth and the dentist has exposed it to blue light. And because a composite consisting solely of glass and synthetic material can hardly be distinguished from a cavity in an x-ray image, SCHOTT also oﬀers special radio-opaque glasses, which make it easy to detect the fillings and prevent the dentist from drilling into a filling by mistake.
To achieve the required transparency with the fine grain size, high demands for purity must be met even while the glass is being manufactured. For this reason, these glasses are melted in a special unit normally used to manufacture optical quality glasses. Unlike their usual process, the experts allow this extremely pure material to cool oﬀ very quickly to create as much stress in the glass as possible, as this makes subsequent processing easier. Today, SCHOTT supplies its fine grain glass powder to the world’s dental industry. While the main focus is currently on Europe and the U.S.A., demand is expanding to customers in all other regions of the world. ”Thanks to many years of experience and advanced manufacturing technology, I am optimistic that we will continue to gain a larger share in this growing market,” said Kessler.