GUIDED SURGERY
NobelGuideĀ
The type of surgical guide in
conjunction with the bone quality and
volume will drive the surgical procedure.
Guided surgery will afford the least invasive surgery protocol. All aspects
of bone quality,
volume and topography are
discovered through CT or cone beam computer
tomography (CBCT) and
virtual implant placement before any incision is made.
The surgical guide is either bone, tissue or teeth borne. In most instances only minimal tissue
reflection or excising a small circular amount of tissue with a tissue punch
through the surgical guide are needed.
The bone is scored with a round burr through the guide, followed by the
pilot drill according to the drill
protocol to establish the osteotomy depth and angulation.
Copious amounts of pre cooled, sterile saline solution should be used to
irrigate the drills and bone. Some guides will allow the use of successively
larger drills through the use of interchangeable bushings in the guide,
just the pilot hole or a number of guides for each larger diameter drill. In which case the surgical guide is
changed to accommodate the next larger drill or discarded after the initial pilot
hole.
Successively larger diameter drills are used in accordance with manufacturer
guidelines in regards to bone quality and implant diameter to achieve the
most ideal osteotomy dimensions.
Tap drill
Depending on the bone quality and structure, the bone is pre tapped only at the
cortical crest or the complete depth of the osteotomy. D3 and D4 type bone
will in most instances not require pre tapping. Instead the implant is allowed
to tap itself in to the softer bone at the time of implant insertion in to the
under sized osteotomy. Once the osteotomy is finalized the implant is picked
up with a high torque surgical motor and driven in to the osteotomy site with
a low speed (30rpm) and clock wise setting. Avoid contaminating the implant
body by touching or placing the implant on the instrument tray before insertion.
Feature indicator
The polished collar of the implant should be above or flush with the crest of
the bone, depending on manufacturer recommendation. Disconnect the surgical
motor from the implant and evaluate the implant position. The anti rotational
feature of the implant should be positioned in relation to the angulation
of the implant. The implant carrier or fixture mount of the implant has in
most cases markings indicating the anti rotational feature position.
For instance, if the implant is inclined toward the buccal, the indicator
should be on the buccal as well. If the inclination is towards the mesial,
the marker needs to be on the mesial too. Utilize a hand ratchet to
finalize proper implant position and remove the implant carrier.
Two stage surgery
Closing the tissue can be done as a one stage or two stage procedure.
Minor bone grafting procedures may be performed before suturing the implant site.
A two stage surgery requires suturing the tissue flap over the installed
implant at the initial implant placement and a second surgery after the
initial healing period to uncover the implant. The two stage protocol involves
installation of a low profile cover screw (included with most implants)
before closing the tissue over the implant and changing the cover screw
with a trans mucosal healing abutment (often a separately purchased item) at
the second stage uncovery. This approach requires additional time to let the
tissue heal and mature around the trans mucosal healing abutment.
One stage surgery
A one stage surgery entails
suturing the tissue around the trans mucosal healing abutment at
the time the implant is placed, eliminating a second surgery to uncover the
implant. The trans mucosal healing abutment is installed instead of the cover
screw and the tissue sutured around the healing abutment, allowing the tissue
to heal and mature around the implant. A reduced treatment time frame, less
trauma and scarring in addition to reduced treatment cost make this option
a popular treatment choice.