Clinical Importance: Almost 10 million dental implants were placed worldwide in 2013, with 3 million of these procedures taking place in the United States. The worldwide market for these implants is expected to increase to $4.0-$5.0 billion in revenue by 2018 as dental implant manufactures target and train general dentists (non-surgically trained) to perform these procedures. The procedure itself requires an osteotomy be drilled into the mandible or maxilla (depending on site of implant) so that the implant can be seated within the boney structures of the jaw. A significant challenge to creating the initial osteotomy is ensuring that no critical structures near to the bone are breached leading to severe post-procedure morbidities. Clinical Limitations: The object of the surgeon is to drill into the bone's medullary canal without breaching the cortical bone protecting critical adjacent anatomic structures. In the case of a mandibular implant, the interior alveolar nerve (IAN) runs along the medullary canal innervating the teeth of the lower jaw, lips, gums, and skin overlying the chin. The IAN is protected by a conduit of cortical bone; if breached during a drilling procedure irreversible nerve injury is possible. In the case of maxillary implants, a cortical bone interface separates the medullary bone of the maxilla from the maxillary sinus. Breaching the cortical bone in this case can lead to severe sinus complications. As more non-specialists enter the market of dental implants, it is imperative that additional guidance is given to prevent a breach of this medullary/cortical interface. Currently, no existing technology is available to provide rel-time guidance during drilling. Proposed Solution: We propose to instrument a standard dental drill with real-time electrical impedance sensing capabilities. The electrical impedance of cortica bone is reported to be more than 20 times greater than that of the cancellous bone found within the medullary cavity. We hypothesize that electrical bioimpedance signatures recorded at the tip of the drill bit will be sufficiently sensitive and specific to detect when cortical bone structure are being approached (prior to breaching). Specific Objectives: We specifically propose to design a custom high-speed electrical impedance sensing circuit that will interface to a dental drill. Impedance will be recorded at the tip of the drill bit and real-time feedback in the form of a colored set of LEDs, an LCD-based display, or auditory signal will be provided to the user informing them when cortical structures are approaching.
We aim to determine the optimal electrical impedance parameters to use and to evaluate a fully integrated prototype in ex vivo mandibular and maxillary bones. Future Directions: RyTek Medical is a small company developing bioimpedance-sensing devices for a variety of clinical applications. This specific device will compliment our existing efforts. By the end of this program we will have demonstrated that the smart sensing drill is functional in an ex vivo model. This will position us to seek Phase II funding to develop a more commercial-ready device and to evaluate in vivo functionality in an animal model and human pre-clinical trials. Additional uses of this technology might include identifying cracks in teeth (impedance of air is much greater that of dental tissue), identifying alveolar bone loss, or use in orthopedic drilling applications.
Dental implantation currently relies on pre-operative imaging technologies to help guide dental surgeons in safely drilling through the jaw to accurately position an implant; unfortunately, these pre-operative images do not provide real-time feedback during the drilling process resulting in the potential for serious post-surgical complications associated with the drill penetration through critical anatomic structures including nerve bundles and sinus cavities. We propose to develop a smart sensing dental drill that is capable of gauging tissue bioimpedance at the tip of the drill bit. This novel technology will provide real-time feedback regarding the position of the drill during the procedure and help dental surgeons to avoid any surgically-related patient injury.