An alternate approach to 3D
imaging that still helps set the
pilot drill in the right direction
by Drs. Levente Z. Bodak-Gyovai and Catherine F. Bodak-Gyovai
Implant dentistry has evolved from simple, freehand
procedures to complex, computer-guided navigation
protocols. Cone-beam computerized tomography
(CBCT) can be used to produce three-dimensional
computerized images and 3D surgical guides for placement
of multiple implants, and while these advanced
digital technologies have moved to the forefront of implantology,
their mastery can require substantial investment
of finances, time and effort to maximize success.
There are occasions when immediate placement of
a single implant, such as the loss of a front tooth, is
necessary to restore cosmesis or functional dentition.
In such cases, practitioners may not have access to a 3D
surgical guide. Dentists who seek an easy method to
insert an implant to replace a missing tooth may consider
a technique that is quick, cost-effective and readily
available in the dental office. Calibrated implant pin
control also provides the ability to adjust the location,
trajectory or depth of the pilot drill, which is essential
to avoid complications whether using freehand or
computer-guided methods.1,2
Placing a dental implant should not be disruptive
to the schedule, because the time requirement for a
single implant, abutment and crown is comparable to
treating a tooth with root canal therapy and placing a
crown. The permanent implant tooth may have room
anywhere in the dental arch. Although a fixed bridge is
an excellent choice, it involves the often-objected invasion
of those neighboring teeth. Dental implants are a
reliable technique for a permanent tooth replacement.
Case selection and applications
Because placing a dental implant is a surgical procedure,
it requires a detailed patient medical history
for comprehensive treatment planning. Certain medical
conditions should prompt a request to consult with
the patient’s treating physician to avoid complications.
For example, the physician, not the dentist, can pause
anticoagulant treatment. Other conditions warranting
medical consultation include history of bisphosphonate
treatments, elevated hemoglobin A1C > 6.5%,
head and neck irradiation, uncontrolled hypertension,
organic heart murmur or antibiotic allergy.
Case selection is essential for success. Start at a
healed site of a lost tooth with adequate bone height
and width. A small mucoperiosteal flap, utilizing a
papilla-saving curvilinear incision, offers clear visibility
for the pilot osteotomy drill. After tooth removal,
implant osteotomy may be simpler when the alveolar
socket is still patent but infection and inflammation
have resolved, soft tissue is pursed or closed, and sufficient alveolar bone height and width remain.
Although CBCT may not be available, routine
periapical radiography is. Multiangle digital periapical
radiography can clearly display vital anatomical structures
that may be within the planned trajectory of the
pilot drill osteotomy. Multiangle digital periapical radiography
offers a variety of applications to identify:
- Typical landmarks such as the size of the
tuberosity, the presence of sinus septae, and the
exact location of the antrum and nasal floor.
- Adequate space to consider the 2 mm safe space
over the mandibular canal roof to the apical end
of the implant as placing the implant shoulder
2 mm subcrestal.
- Critical structures including a safety zone at the
mental foramen, the mental nerve loop and the
true mandibular incisive canal.
- Quality or limitation of bone, such as at the
tuberosity, poor bone quality, maxillary sinus
extension and anatomical limits.
- Unexpected anatomical variants such as a
retromolar branch of the inferior alveolar nerve.3
- Position and orientation of remaining natural
teeth, roots and implants.
Creating and using the CIPC
The calibrated implant pin control (CIPC, Fig. 1)
combined with digital periapical radiography will
guide the pilot osteotomy drill safely to avoid any important
anatomical structures.
Fig. 1
It is possible to construct the CIPC by using two
straight handpieces, a latch drill, a heatless stone, a
thin separating corundum disc and a caliper. Shape
the latch drill to match the silhouette of the pilot osteotomy
drill, and form a 1-mm-long, 0.5-mm-wide
tip. Create grooves at sites you select, such as at 5 and
11 mm measured from pin tip along the shaft. Cut
the latch drill to a length of 17 mm and smooth with
a rubber wheel. At the end of the latch drill, create a
groove to attach a long dental floss for safety and the
CIPC is now complete. I chose a 17 mm total length
to prevent interocclusal interference as the patient occludes
on the bite plate of the sensor holder.
Using the CIPC to measure osteotomy depth, slip
a small-diameter orthodontic elastometric separator
ring onto the CIPC and, with a straight hemostat, introduce
it into the pilot osteotomy. Adjust the ring to
the entrance of the osteotomy orifice for depth length
reference. The ring on Fig. 1 illustrates depth at 9 mm.
With the CIPC in situ, expose a digital periapical radiograph.
This CIPC procedure is similar to the well-known
root canal pin control, where I use a root canal file with
a small rubber disc, and slide it into the root canal to
determine the root canal length on a periapical radiographic
view.
Determining bucco-lingual relation
Comparison of the digital image of the straight
periapical radiographic view with the mesial and distal
projections is used to determine the bucco-lingual
relation of an object of interest, per Clark’s horizontal
tube shift rule.4 When the tube is shifted horizontally,
the object moves in the same direction on the screen if
it is located on the lingual side. For example, when the
pilot osteotomy is near the mental foramen, it can be
directed as to bypass the foramen on the lingual side.
Richard’s buccal object rule5 describes vertical tube
shift. When the object of interest is on the buccal side,
it moves in the same direction as the X-ray beam is directed.
For example, the inferiorly directed beam shifts
the buccally located inferior alveolar canal apically, related
to the tip of the CIPC on the screen. Similarly,
the coronally aimed beam moves the buccally located
object on the view coronally, closer to the CIPC.
The benefit of using the CIPC is that the tip of
the pin is at the same location as the pilot drill tip in
the osteotomy. Knowing the calibrations of the CIPC,
the exact distance measurements are obtained in actual
millimeters to a vital structure by using the software
length measurement on the screen.
Calculating magnification distortion
Whether using short or long cone, or bisecting or
paralleling techniques, there are inherent distortion errors
of intraoral periapical radiography. Magnification
discrepancies of foreshortening or elongation will be
present on the views of the screen. However, because
the 1-mm-long tip of the CIPC in the pilot osteotomy
will suffer the same magnification error as the distortion
of the immediate intraosseous surrounding anatomy,
the distance from the end of that 1-mm CIPC tip
to the nearby vital anatomy will receive the same magnitude
of magnification distortion. This dimensional
change will alter the tip of the CIPC to the same degree
that it will affect the short distance from that end to
the nearby vital structure. This permits calculating the
distances to negotiate tight intraosseous spaces for the
implant osteotomy and to avoid critically important
anatomical landmarks.
Next, insert the implant into the completed osteotomy.
Place the healing plug and pack the saved autogenous
osteotomy bone graft, then cut a small collagen
plug cover. For primary closure, use resorbable
sutures to prevent salivary contamination. Conclude
the procedure with final periapical radiographs and
photographs.
For a permanent implant, I allow time for osseointegration
per two-stage protocol. When it’s time
to test implant osseointegration, locate the implant by
using a pin for a periapical radiograph. To uncover the
healing plug under soft and hard tissues, use a highspeed
#4 round bur.
Test the osseointegration with the guide pin and
prepare room with sulcus reamers to insert the selected
implant abutment and proceed with crown preparation.
Make the final radiographs and photographs and
schedule a six-month recall.
Case 1
This 77-year-old patient requested implant replacement of
long-lost #30 and #31 (Fig. 2). With the help of CIPCs in the pilot
osteotomies (Figs. 3–5), I inserted at #30 a 4.5-by-8-by-3-mm
implant and at #31 a 5-by-6-by-3-mm implant, both from Bicon,
into the completed osteotomies (Fig. 6). I located the implant
with the use of an explorer (Fig. 7), assessed osseointegration
and placed the abutments into the implant wells (Fig. 8).
PFM crowns were bonded to complete the treatment (Fig. 9).
Fig. 10 shows the two-year follow-up.
Case 2
This 77-year-old patient fractured #14 (Fig. 11). After
atraumatic sectioning removal of the roots (Fig. 12) and healing
of the soft tissues, and with the help of the CIPC (Fig. 13), I could
locate just enough space next to the antrum for a 4.5-by-8-
by-3 mm implant (Fig. 14). The implant was inserted precisely
between the root and antral wall without touching them, and
I completed implant tooth #14 (Figs. 15 and 16). Fig. 17 shows
the two-year follow-up.
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Conclusion
Periapical radiography is routine before and immediately
after implant surgery.6 Also, intraoperative
periapical radiography is used for many dental procedures.
Employing CIPC periapical radiography imparts
negligible additional ionizing radiation. With my
0.04-second exposure time, a patient receives an estimated
0.08-microsievert effective dose. Investigators
using the same X-ray tube assessed 0.8-microsievert
effective dose at 0.4 second average exposure time,7 indicating
excellent ALARA compliance.
Of the 200 short implants I placed in our office,
I have never encountered a fractured or loose implant
or abutment, despite a variety of challenging placements.
My series includes cases requiring a 15-degree
abutment. In cases with reduced alveolar bone height,
using short implants may avoid bone augmentation.
Short and strong, as illustrated (Fig. 18) with a 10-year
follow-up (Fig. 19).
Placing dental implant teeth can change lives, and is
one of the most rewarding aspects of dental practice.
Fig. 18
Fig. 19
References
1. Tullarico M, Esposito M, Xhanary E, Caneva M, Meloni SM. “Computer Guided Vs. Freehand Placement of Immediately Loaded Dental Implants: 5-Year Post Loading
Results of Randomized Controlled Trial.” Eur J Oral Implantol. 2018; 11(2): 203–13.
2. Mandelaris GA, Stefanelli LV, and DeGroot, BS. “Dynamic Navigation for Surgical Implant Placement. Overview of Technology, Key Concepts and a Case Report.”
Compendium. 2018; 3(9): 614–21.
3. Filo K, Schneider T, Kruse AL, Gratz Lochner, KW, Lubbers HT. “Frequency and Anatomy of the Retromolar Canal Implications for the Dental Practice.” Swiss Dent J SSO
2015; 125: 278–85.
4. Clark CA. “A Method of Ascertaining the Relative Position of Unerupted Teeth By Means of Film Radiography.” Odontol Soc. R. Soc. Med. Trens. 1909; 3: 87.
5. Richards AG. “Technique for Roentgenographic Examination of Impacted Mandibular Third Molars.” J Oral Surg (Chic).1952; 10(2):138–41.
6. Saltzburg N, Kang P. “Observed Healing of an Immediately Placed Implant in a Molar Site Without Bone Replacement Graft or Primary Closure.” Compendium. 2020;
41(6): 326–30.
7. Granlund C, Thilander-Klang A, Ylhan B, Lofthag-Hansen S, Ekestubbe A. “Absorbed Organ and Effective Doses From Digital Intra-Oral and Panoramic Radiography
Applying the ICRP 103 Recommendations for Effective Dose Estimations.” Br J Radiol. 2016; 89(1066): 20151052.
Dr. Levente Z. Bodak-Gyovai
obtained his dental education at
Semmelweis University in Budapest,
Hungary, where he became an
assistant professor, and from McGill
University in Montreal, where he
earned a MSc degree. Bodak-Gyovai
continued postgraduate training
at the University of Pennsylvania, where he became an
assistant professor in the dental school and published a
textbook on oral medicine. He later earned certification
in orthodontics/orthopedics from the United States
Dental Institute and in Bicon implantology from the Bicon
Institute. After 44 years in general dental practice in
Media, Pennsylvania, he recently retired.
Dr. Catherine Foley Bodak-Gyovai is
a neurologist and pediatrician who is
the author or co-author of 70 peerreviewed
medical research studies,
reports and abstracts. A graduate
of the University of Pennsylvania
School of Medicine, Bodak-Gyovai
taught at the Temple University
School of Medicine, the University of Pittsburgh School of
Medicine and Jefferson Medical College in Philadelphia.
She recently retired from her specialty medical practice
at Nemours Children’s Hospital in Wilmington, Delaware.
After her marriage to Dr. Levente Bodak-Gyovai, she
developed an interest in the medical aspects of oral
health and restorative dentistry.