Increasing Productivity by Effective Use of Four-Handed Dentistry – Part 3: Instrument Transfer Technique
Hidden Syringe Transfer

The hidden syringe transfer is named as such because it takes place out of view under the chin of the patient. It enables the operator to receive the anesthetic syringe safely and out of the patient’s line of sight thus avoiding undue patient stress. This transfer also occurs within the transfer zone.

This transfer requires that the assistant and operator plan in advance the technique to avoid the potential of a needle stick. Often the operator prefers to transfer the instrument behind the patient. This area is outside the transfer zone, causing the assistant to use a Class V movement and violate safe transfer. This transfer can be adapted to the use of wand type anesthesia very effectively. Care should be taken that the base unit is located nearby the assistant for easy access. Using a traditional anesthetic syringe the following steps may be followed:

• A 2 x 2 gauze is passed to dry the site. Topical anesthetic may be applied with a cotton-tipped applicator if desired (Figure 25).

• The protective cap on the needle is loosened slightly (Figure 26).

• The syringe is held in the assistant’s right hand when assisting a right‑handed operator while the assistant stabilizes the operator’s hand using a firm grasp (Figure 27).

• The operator positions the right hand upright with the index, and middle fingers extended along with the thumb to receive the syringe. While the assistant holds the operator’s right hand firmly the thumb ring of the syringe is positioned over the operator’s thumb and lowered to rest between the awaiting index and middle fingers.
• The assistant’s hand carefully removes the protective cover while maintaining the firm grasp of the operator’s right hand to avoid any inadvertent movement. Once the cap is removed and the assistant’s right hand is away from the exposed needle the operator’s hand can be released to signal that the syringe is ready for use.
• The cover is placed into the recapping device while the operator administers the anesthetic (Figure 28). If the patient is a small child, the assistant can gently place his or her arms over the child to prevent a sudden movement that could result in injury during the injection procedure.

• The retrieval of the syringe is similar to the delivery in that, using the left hand, the assistant grasps the operator’s right hand upon withdrawal of the syringe from the patient’s mouth to hold it in a predictable position. The assistant then grasps the syringe by the barrel to avoid contacting the contaminated needle. A gauze sponge is exchanged for the syringe to use as a compress over the injection site.
• The syringe is placed in a recapping device (Figure 29). Though it requires a movement out of the operator’s zone, some operators prefer to replace the syringe in the recapping device to avoid a potential accident.

• The mouth may be rinsed at this time if any anesthetic was dropped on the tongue.
• It should be noted that some operators prefer to transfer the syringe to the recapping device behind the chair. This is acceptable, but does require the dentist to reposition his or her body and move the eyes from the operative field, but may provide more comfort if the potential for a needle puncture is possible.