Formocresol is a historical dental agent used for decades to treat nerve tissue inside children’s decayed primary teeth. The solution, originally formulated by Buckley in the early 1900s, is a combination of formaldehyde, cresol, glycerin, and water. Despite its long-standing use, it remains controversial due to its chemical composition. The presence of formaldehyde raises questions about its safety profile for young patients.
Primary Application in Pediatric Dentistry
Formocresol is primarily used in a pulpotomy, a procedure often performed on primary (baby) molars with deep decay. A pulpotomy is necessary when a cavity has reached the pulp chamber, which contains nerves and blood vessels, but the infection is mostly confined to the crown. The procedure involves removing the infected pulp tissue from the crown while aiming to keep the nerve tissue in the roots healthy.
After the infected pulp is removed, a small cotton pellet soaked in formocresol is placed in the pulp chamber for a short period. The material acts as a tissue fixative and an antimicrobial agent, sterilizing the remaining pulp tissue in the root canals. This action, known as mummification or devitalization, preserves the remaining tissue so the baby tooth can be retained until it naturally falls out.
Clinical studies show that formocresol pulpotomies historically achieved high success rates, often ranging from 70% to 97%, in maintaining the tooth until exfoliation. This success rate and the material’s ability to quickly treat infected tissue made it the standard of care in pediatric dentistry for many years. Retaining the primary tooth is important because it holds space for the permanent tooth underneath and allows for proper chewing and speech development.
Safety Profile and Regulatory Concerns
The controversy surrounding formocresol centers on its main component, formaldehyde, an alkylating agent. Formaldehyde has been classified by international bodies, including the International Agency for Research on Cancer (IARC), as a known human carcinogen when exposure is high. Concerns have been raised over the potential for systemic absorption of this chemical into the child’s body during the pulpotomy procedure.
Research indicates that approximately 1% of the formocresol dose applied to the pulp is systemically absorbed. However, the amount of formaldehyde used in a single pulpotomy is minute, estimated between 0.02 and 0.1 milligrams. Proponents argue that the human body naturally produces and metabolizes formaldehyde daily. Therefore, the quantities introduced during the dental procedure are insignificant compared to daily environmental exposure from food and air.
Despite the low-dose argument, concerns remain regarding potential local effects, such as tissue irritation and immune sensitization. Some studies suggest that formocresol may cause chronic inflammation or necrosis in the remaining pulp tissue rather than promoting true healing. These findings, combined with formaldehyde’s known toxicity profile in large quantities, have led many clinicians to advocate for safer alternatives.
Evolution of Clinical Practice and Alternatives
Safety concerns and the move toward biologically compatible treatments have driven a shift away from formocresol in modern pediatric dentistry. The goal of contemporary pulp therapy is no longer to fix or devitalize the tissue, but to encourage the remaining dental pulp in the roots to heal and repair itself. This philosophy change has promoted the search for materials with better biocompatibility and reduced systemic risk.
One widely accepted alternative is Mineral Trioxide Aggregate (MTA), a powder that forms a cement-like material when mixed with water. MTA is regarded for its ability to induce the formation of a hard tissue barrier, effectively sealing the remaining pulp tissue and promoting healing. Clinical trials frequently show MTA yielding comparable or superior success rates to formocresol, establishing it as a current gold standard for pulpotomies.
Other common alternatives include Ferric Sulfate and various calcium silicate-based cements, such as Biodentine. Ferric sulfate is a hemostatic agent that works by coagulating blood proteins, controlling bleeding and creating a surface seal over the radicular pulp. These non-aldehyde-based materials offer equivalent clinical outcomes while avoiding the formaldehyde component, making them the preferred choice in many dental practices.