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Consultants’ Comments

  • “Easy to use and incorporate into the routine.”
  • “Patients became anesthetized very quickly.”
  • “Great solution for patients who are hard to numb.”
  • “After administering a mandibular block, I can begin working in 1-2 minutes.”
  • “There is a short learning curve to preparing the pen.”
  • “Provide a system with smaller doses or single dose.”


Onset is a chairside anesthetic buffering system. It is indicated to reduce injection pain. It does this by raising the pH of the standard dental cartridge of lidocaine with epinephrine (average pH is 3.5) to a more physiologic level (body pH is 7.4). The published literature on buffering suggests that this also increases the effectiveness of anesthetic and hastens the onset of anesthesia. The Onset system adds a precise amount of sodium bicarbonate neutralizing solution directly to the anesthetic cartridge immediately before injection. The Onset system includes an Onset Mixing Pen; Onset Cartridge Connectors; and Onpharma Sodium Bicarbonate Inj., 8.4%, USP Neutralizing Additive Solution, a sterile, non-pyrogenic, solution of sodium bicarbonate in water for injection. At the start of the day, the practitioner loads the Mixing Pen with a sodium bicarbonate cartridge. During the day, immediately before delivering a local anesthetic injection, the practitioner connects a standard 1.8 mL anesthetic cartridge to the Mixing Pen, which transfers a precise amount of buffering solution into the anesthetic cartridge, while automatically removing the same amount of anesthetic. The now-buffered cartridge is disconnected from the mixing pen, loaded into the dental syringe, and the injection is delivered per the practitioner’s normal technique. The standard one-week Trial Kit contains one reusable Onset Mixing Pen; four 3-ml cartridges of Onpharma Sodium Bicarbonate Inj., 8.4%, USP Neutralizing Additive Solution; four Onset Cartridge Connectors training/supporting materials; and a Quick Start Guide. Seventeen consultant practitioners evaluated Onset in 394 uses. They gave Onset a 92% clinical rating.


Product Features

The Onset system is easy to use and easy to incorporate into a practice. Consultants reported that patients became anesthetized very quickly with the buffered anesthetic. The mixing pen is easy to load, and once loaded the mixing pen can buffer up to nine carpules of anesthetic in a clinical day. Dental assistants noted that they would like a more durable metal device rather than plastic and a better, more precise way of visualizing the amount of sodium bicarbonate remaining in the cartridge. Seventy-six percent of consultants stated that using Onset saved clinical time by allowing them to start treatment right away. Many consultants would like the option of a smaller cartridge for days in which they anticipate administering fewer injections. Seventy-eight percent of consultants reported that the Onset system was better than their current method to decrease injection pain and would switch to it; 94% would recommend the Onset system.

Clinical Tips

  • Buffer the anesthetic immediately before use (do not buffer and allow to stand).

  • This product is labeled for use only with lidocaine at this time.

  • Once the sodium bicarbonate cartridge has been loaded into the pen the cartridge should be used within 12 hours. Do not keep overnight once opened.

  • Make it a habit to change buffer and cartridge connector at the same time.

  • Store at room temperature.

  • Do not autoclave the mixing pen; use a barrier sleeve or disinfectant wipe.