Dental putty is a specialized, paste-like material used in dentistry to capture a precise, three-dimensional mold of a patient’s oral structures. This highly viscous substance is engineered to be malleable when handled, allowing it to be easily shaped and loaded into an impression tray. Its fundamental purpose is to create a negative reproduction of the teeth, gums, and surrounding tissues. Dental laboratories use this mold to fabricate restorations and appliances, relying on the material’s ability to replicate fine details.
The Chemical Composition of Dental Putty
The most common and modern form of dental putty is based on Polyvinyl Siloxane (PVS), also known as addition-cured silicone. This material is a two-component system, typically supplied as a “base” paste and a “catalyst” paste, which are mixed in equal parts. The base material contains vinyl-terminated polysiloxane polymers, while the catalyst component includes hydrogen-terminated polysiloxane and a platinum salt catalyst.
The putty’s consistency is controlled by incorporating a high concentration of inorganic fillers, such as silica. These fillers are responsible for the thick, heavy-body nature of the putty, distinguishing it from lower-viscosity wash materials. PVS chemistry is valued for its superior dimensional stability, meaning the impression holds its shape accurately over time with minimal shrinkage after setting. Some formulations include surfactants to enhance hydrophilicity, making the putty compatible with the naturally moist environment of the mouth.
Professional Applications in Dentistry
Dentists utilize dental putty for a wide variety of procedures that demand structural accuracy. One of its primary uses is in the “putty-wash” impression technique, where the stiff putty serves as a custom-fitted tray for a subsequent, more fluid wash material. The high-viscosity putty is first seated over the patient’s arch, creating a preliminary impression that stabilizes the tray and provides space for the low-viscosity wash to capture minute details around prepared teeth. This two-stage process is routinely used for making impressions for crowns, bridges, inlays, and onlays.
Putty is also frequently employed for bite registration, a procedure that records the exact relationship between the upper and lower jaws. In this application, a rigid polyvinyl silicone putty is placed between the opposing arches, and the patient closes into it. The material’s final hardness ensures the registration remains stable and does not distort when handled or shipped to the dental laboratory.
Furthermore, dental putty is used to create a matrix, which acts as a mold for fabricating temporary restorations like provisional crowns or veneers. A putty mold is taken of the tooth before preparation, and the resulting impression is then filled with a temporary material and seated over the prepared tooth, quickly restoring the original shape.
Understanding the Setting Reaction
The transformation of dental putty from a soft, workable paste to a rigid mold occurs through a chemical process called addition polymerization, or addition-curing. When the base and catalyst are kneaded together, the platinum catalyst promotes a reaction between the vinyl groups and the hydrogen groups on the respective polysiloxane chains. This reaction causes the long polymer chains to link together, forming a stable, cross-linked, rubber-like solid.
The setting process is divided into two phases: the working time and the setting time. The working time is the period during which the putty remains soft enough to be mixed, loaded into a tray, and seated in the mouth, typically lasting between 1.5 and 2.5 minutes for regular set materials. The setting time is the total time from the start of mixing until the material has fully hardened and can be removed from the mouth, often ranging from four to five minutes for a regular set. Manufacturers also offer fast-set versions, which can reduce the setting time to as little as two to three minutes, benefiting patients with strong gag reflexes.
Dental Putty in At-Home and Emergency Kits
Dental putty has found a significant role outside the dental office, particularly in the direct-to-consumer clear aligner industry. At-home impression kits often contain a PVS-based putty system for patients to take their own dental impressions. The kit includes the base and catalyst putties, which the user mixes by hand and presses into a tray to capture the mold of their teeth.
This self-administered impression is then mailed to a lab to create customized clear aligners, bypassing the initial in-office visit. While convenient, the accuracy of these at-home impressions depends on the user following the time-sensitive instructions, as errors can lead to poorly fitting appliances. Separately, temporary dental repair kits for emergency use, such as fixing a lost filling or crown, contain different materials that function as a temporary putty. These non-PVS products, often made of zinc oxide or polymer beads, are short-term solutions intended only to protect the tooth until professional dental care can be obtained.