This proposal aims to enable a new generation of high-speed, low-cost, wavelength-flexible swept source
optical coherence tomography (SS-OCT) imaging device technology targeting applications in dental imaging and
based on microelectromechanical systems vertical cavity surface emitting lasers (MEMS-VCSELs) and planar
lightwave circuits (PLCs). MEMS-VCSELs provide an unmatched combination of high and variable axial scan
rate, dynamic single mode operation enabling long imaging range, and the potential for low-cost volume
manufacturing through wafer scale fabrication and testing. The proposed effort involves a collaboration between
Praevium Research, which pioneered MEMS-VCSELs for SS-OCT, and the University of Washington (UW), a
world leader in SS-OCT structural and angiographic imaging in dentistry. This work seeks both to advance dental
imaging science through new imaging tools and promote commercialization in cost-sensitive dental markets.
Praevium Research will develop new high axial scan rate MEMS-VCSEL swept sources near water
absorption minima at 1700nm and 2200nm, to enable longer imaging range due to reduced scattering at longer
wavelengths. Imaging at these wavelengths may be particularly important in improving the ability of OCT to
noninvasively determine periodontal pocket depth. In addition, Praevium will combine emerging electrically
pumped MEMS-eVCSELs at 1310nm with advanced PLC technology, replacing bulky and environmentally
sensitive fiber networks commonly employed in SS-OCT by lithographically defined waveguide devices. This
will allow a radically miniaturized low-cost and stable SS-OCT subsystem with MEMS-VCSEL, optical amplifier,
wavelength monitoring, and MZI interferometers on a single chip in a compact butterfly package, overcoming
long-standing cost barriers to SS-OCT in dentistry.
UW collaborators will use various generations of high axial scan rate MEMS-VCSELs, starting at 1310nm
and migrating to 1700nm and 2200nm as these latter sources are developed, to develop real-time wide field of
view (FOV) whole mouth structural (OCT) and label-free angiographic (OCTA) periodontal imaging. Current
methods for assessing periodontal disease rely on invasive probing, induce unnecessary pain and bleeding, and
are error-prone due to inconsistent frequency and force of probing and due to the complexity of gingival thickness
and appearance. The proposed SS-OCT technology, by contrast, has the potential to create qualitative and
quantitative imaging of microstructure and vasculature in gingival tissue. This will enable a comprehensive
periodontal imaging diagnostic suite which can assess periodontal attachment, alveolar bone quality and level,
gingival inflammation, sub gingival calculus plaque and tissue biotype. Such a system can also provide an
objective means to determine and evaluate the prognosis of periodontal, regenerative and restorative therapies,
improve computer-aided design and machining (CAD/CAM) for dental restorative procedures and planning, and
become a reliable tool for long term monitoring and maintenance in clinical practice for oral health.
