Art-3-4-2020
www.stomaeduj.com ORAL IMPLANTOLOGY
TEMPERATURE CHANGES IN BONE USING AN AIR
Original Articles
SCALER EX VIVO
Dana M. Marzocco1a*, Sean Lee2b, Kenneth S Kurtz1c, Javed Fawad3d , Rafael Delgado-Ruiz1e , Georgios E Romanos2,4f
1
Department of Prosthodontics and Digital Technology, Stony Brook University, Stony Brook, New York, USA
2
Department of Periodontology, School of Dental Medicine, Stony Brook University, Stony Brook, New York, USA
3
Department of Orthodontics, Eastman Institute for Oral Health, University of Rochester, NY, USA
4
Department of Oral Surgery and Implant Dentistry, School of Dental Medicine, Johann Wolfgang Goethe University, Frankfurt, Germany
a
DMD, Clinical Assistant Professor; e-mail: danamarzocco@gmail.com; ORCIDiD:
b
DMD; e-mail: sean.t.lee11@gmail.com; ORCIDiD:
c
DDS, FACP, Clinical Professor, Director; e-mail: kenneth.kurtz@stonybrookmedicine.edu; ORCIDiD:
d
BDS, PhD; e-mail: fawjav@gmail.com; ORCIDiD: https://orcid.org/0000-0002-9253-1989
e
DDS, MSc, PhD Associate Professor; e-mail: rafael.delgado-ruiz@stonybrookmedicine.edu; ORCIDiD: https://orcid.org/0000-0003-1721-0509
f
DDS, PhD, DMD, Professor, Director; e-mail: georgios.romanos@stonybrookmedicine.edu; ORCIDiD: https://orcid.org/0000-0002-5952-4752
ABSTRACT https://doi.org/10.25241/stomaeduj.2020.7(4).art.3
Introduction Frictional forces induced by osteotomy devices may induce an unwanted temperature increase
in bone. This experimental study aimed to evaluate temperature changes produced in dense bone by three
different osteotomies produced by an air scaler device.
Methodology Under the same parameters, forty-five linear osteotomies were prepared on the cortical layer
of fresh porcine ribs resembling dense bone with three different air scaler insert tips: sagittal saw (Tip A),
diamond ball (Tip B) and square chisel (Tip C). The length of the osteotomies was standardized to 10 mm in
length. The depths of cuts ranged from 0.5 mm to 2.0 mm. The future osteotomy areas were marked with
a graphite pen, and thermocouple microprobes were placed 1 mm lateral at both sides of the marks. The
maximum temperature, differential temperature, and time for cut completion were recorded. Analysis of
Variance and Kruskal Wallis test were used for the group comparisons.
Results Tip A induced the highest of the maximum temperature recordings (Tip A: 48.0 oC). Tip B and C
produced comparable maximum temperatures (Tip B: 43.6 oC and Tip C: 44.0 oC). Total mean temperature
change increased more for Tip B (4.13) and less in Tip C (0.2). Timing of cuts ranged from 30 seconds to 5
minutes (2.30 ± 1.76 min). Overall average temperature change was less than 100 oC within one minute.
Conclusion Osseous site preparation can be achieved with the Air scaler and different air scaler inserts
without inducing significant critical thermal changes in bone.
KEYWORDS
Air Saler; Heat Generation; Osteotomy; Sonic Device; Temperature Change.
1. INTRODUCTION water jet, and ultrasonic instruments [2]. The air
scaler device may be useful for procedures including
Bone osteotomy is a frequent procedure in oral and implant bed preparation, linear osteotomies, sinus
orthopedic surgery [1]. In addition to the conven- augmentation, bone harvesting and bone splitting.
tional rotary and manual methods, there are a This sonic device operates using compressed air at
number of instruments and techniques that can a lower frequency (6,000 Hz) than other respective
be utilized for an osteotomy. These include laser,
OPEN ACCESS This is an Open Access article under the CC BY-NC 4.0 license.
Peer-Reviewed Article
Citation: Marzocco DM, Lee S, Kurtz KS, Calvo-Guirado JL, Fawad J, Romanos GE. Temperature changes in bone using an air scaler Ex Vivo, Stoma Edu
J. 2020;7(4):252-258.
Received: October 32, 2020; Revised: November 02, 2020; Accepted: November 13, 2020; Published: November 16, 2020
*Corresponding author: Dana M. Marzocco; School of Dental Medicine, Stony Brook University, 1100 Westchester Hall, Stony Brook, NY 11794-8712;
Tel/Fax: (631) 632-3161; e-mail: danamarzocco@gmail.com
Copyright: © 2020 the Editorial Council for the Stomatology Edu Journal.
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Temperature changes in bone using an air scaler
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Original Articles
Figure 1. Air scaler tips for the ex vivo study; left to right Tip A (sagittal saw),
Tip B (diamond ball), Tip C (square chisel).
Figure 2. Osteotomies in the bovine rib bone.
devices. The use of an air scaler with internal
irrigation is thought to protect the surrounding
nerves and soft tissues during the preparation of
osseous structures [3]. There have been previous
studies, which indicated both sonic and ultrasonic
devices resulted in almost no signs of damage
to the bone [4]. The thermal changes induced by
osteotomy devices can irreversibly affect the bone
[5]. It has been demonstrated that an increase in 10
or more degrees (over a normal body temperature of
37ºC) for one minute could induce unwanted effects
in osseous structures such as osteocyte death,
empty lacunae, and reduced vascularization (also
called bone osteonecrosis) [6,7].
An additional study [8], also indicated that the bone
regeneration was reduced when the temperature
was increased. It has been shown that consistent Figure 3. Location of the thermocouples and osteotomies
prepared by the air scaler.
heating over 50 oC for one min has induced in vitro
bone tissue necrosis [9]. As a consequence of the
frictional forces exerted by cutting instruments
during the osteotomy, the bone temperature is The air scaler was set to output level 3 (6,000
increased. The mechanism for thermal osteonecrosis Hz, amplitude 240 μm, 71 dB). The air scaler was
is multifactorial; the local increment of temperature operated using internal irrigation with 50% of water
can induce dehydration of the bone tissues, flow. Three surgical tips were selected for this study
the osteocytes will suffer rupture of the cellular (Fig. 1):
membrane (apoptosis), and the bone vascularization - Tip A - Sonicflex bone tip, sagittal saw (#83),
will be reduced, resulting in bone ischemia. Besides, - Tip B - Sonicflex bone tip, diamond coated ball (#81)
pre-osteoclastogenic gene expression is increased and the
by initiating bone resorption [10]. - Tip C - Sonicflex bone tip, square chisel (#80).
The thermal effects induced by the air scaler during Tip A (sagittal saw) and Tip C (square chisel) had
osteotomies are unknown; the potential effects of polished, steel cutting surfaces. Tip B (diamond ball),
different scaler tips are not clear. The purpose of had a rough diamond cutting surface (Fig. 1). For this
this study was to assess ex vivo the temperature ex vivo study, cuts were made in fresh dense bovine
changes induced by an Air scaler instrument in bone rib. The rib was denuded from soft tissues and the
preparation. surface was cleaned with water. The bovine rib was
placed on a flat surface for standardization of the
2. METHODOLOGY osteotomies. Room temperature was used as the
initial surface temperature.
An air scaler (Sonicflex quick 2008/L; KaVo, Biberach A template was prepared and transferred to the rib
an der Riss, Germany) was used in this investigation. for each of the tips. The template indicated twenty
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Original Articles Table 1. Temperature changes in relation to the used tip of the air scaler.
Table 2. Required times for osteotomy procedures using different inserts.
Table 3. Maximum temperature changes for different inserts.
individual cuts approximately 10 mm in length next osteotomy site and were monitored for their
(Fig. 2). The width of each cut was indicated by the stabilization at room temperature.
individual surgical tip. Once the room temperature was noted, the next
A graphite pencil was utilized to mark the approximate cut could be performed and recorded. Timing was
position of the proposed cuts and placement of the recorded in seconds and minutes with the beginning
thermocouples. Two thermocouples (Model no. IT-23 of the cut and ended when the operator completed
Thermocouple microprobe, diameter .003” insulated the cut. The length of cuts was predetermined to
with extruded TFE Teflon, Physitemp instruments, 10 mm using the template as described previously.
Clifton, NJ, USA) were utilized to assess the thermal All cuts were performed by the same operator.
changes. One was placed at the coronal end of the Thermocouples were connected to an electronic
proposed cut, the second at mid-length aspect. digital thermometer system (ADInstruments,
Thermocouples sites (coronal and mid-length were Inc., Colorado Springs, CO, USA) that allowed the
placed approximately 1 mm lateral to each proposed continuous reading of the temperatures. Each site
cut) (Fig. 3). (coronal and mid-length) had an individual output.
The sites for each thermocouple were prepared prior The output from each thermocouple was recorded
to performing the proposed cuts. Each thermocouple individually. A software program (Lab Chart,
was secured in cortical and cancellous bone. All tips ADInstruments, Inc.) was used to record temperature
were new and unused. Each tip (A, B, C), was used to readings (in Celcius), from each thermocouple.
make 15 cuts each in the bovine rib; 45 osteotomies
were performed in total. 2.1. Statistical Analysis
For each subsequent osteotomy, the bovine rib
was allowed to return to the room temperature The average temperature change was calculated
of 21oC. Thermocouples were relocated to the for the mid-length and laterally positioned
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Original Articles
Figure 4. Box plot showing the times required for
osteotomies using the different a Air scaler inserts.
Figure 5. Box plot showing the maximum
temperature increase for osteotomies performed
ex vivo using an air scaler with different inserts.
thermocouples (Table 1). An average temperature (p = 0.00008) compared to Tip A and B. The maximum
change was determined for each tip (A, B, C). The temperatures reached for each tip were as follows:
standard deviation was calculated for the mid-length Tip A: 48.0o C, Tip B: 43.6 o C, and Tip C: 44.0 o C.
and lateral thermocouples. An average standard Overall the temperature change using the different
deviation was determined for each tip (A, B, C), as tips (A, B, C) was less than 10 degrees (Fig. 5). The
well as time. standard deviations were higher for Tip A. Tip B
Descriptive statistics, mean and standard deviations, and Tip C showed comparable standard deviations
and lower and maximum quartiles were used to (Table 3). Statistical comparisons showed a higher
present the data. ANOVA analysis was used for the maximum temperature for Tip B compared to Tip C
comparison of maximum temperatures between (p = 0.00452). There were no significant differences
groups. between Tip A and Tip B (Table 3).
A post-hoc analysis was completed using the Tukey
test. The time required to complete the linear 4. DISCUSSION
osteotomies was compared using the Kruskal Wallis
test for multiple independent samples. The software This experimental study aimed to evaluate the
StatPlus: mac, AnalystSoft Inc. -statistical analysis temperature changes and time required to complete
program for macOS. Version v7. See https://www. linear osteotomies with three different Air scaler
analystsoft.com/en/ was used for the statistical inserts. The operators in this study were calibrated,
analysis. and the experimental design was carefully controlled.
The temperature change in this study was less than
3. RESULTS 10 degrees for all tips (A, B, C) (Fig. 5). This is less than
the critical threshold, which could induce unwanted
For each tip (A, B, C), the timing of cuts ranged from effects in osseous structures (Table 1).
30 sec. to 5 min (2.30 ± 1.76 min) (Fig. 4 and Table 2). It is possible that the irregular, saw type surface of Tip
The significant lowest time was observed for Tip C A contributed to the increased temperature change.
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Tip B (ball shape) had a larger cutting surface area as of altering the osseous tissue, while sparing soft
Original Articles compared to Tip A and Tip C, which was significantly tissue structures. However, previous studies and
thinner. Tip B had an overall larger surface area as evidence suggest that piezosurgery may generate a
compared to Tip A and C. The diamond cut surface high amount of heat production [9, 15, 16]. Without
may lead to less heat generation. Tip C (chisel) had a doubt, it is up to the individual practitioner and the
smooth polished surface, which may account for less clinical indication which device is appropriate for
heat generation. This tip was not sharp and therefore their clinical practice.
additional mechanical pressure was required in Overall, the air scaler does not induce significant
order to create the osteotomy. A previous article [11] thermal changes in the bone and can be used in a
has demonstrated that an increase in temperature safe manner. The thermal increase induced in the
was inversely proportional to the diameter of the bone by three different air scaler inserts are within
cutting tips. a safe range. The experiment conditions along with
There are very few studies which examine air scaler the continuous irrigation during the procedures
heat generation. There are no studies that exist potentially contributed to this finding.
which compare the air scaler to piezoelectic. There Although it was not analyzed in this study, the depth
are studies which have compared piezoelectric of the cut made depends on the design of the insert
to conventional drilling [12], and ultrasonic to tip. Flat tips are more feasible for deeper cuts, while
conventional drilling [13]. round tips are more feasible for superficial cuts and
These comparisons are important for any clinician osteotomies. The time required for the completion
who is considering adding one of these devices to of the osteotomies was dependent on the insert
their clinical practice. design; flat designs were more efficient for the linear
The air scaler has multiple applications in dentistry. osteotomy completion.
It has the capability to perform osteotomies, bone This study’s strengths are the strict calibration of
splitting, tooth removal, residual root removal, and the operators, and the experimental set-up that
window preparations for sinus augmentations [4]. In allowed the control of all the experimental variables.
addition, it has been utilized to perform atraumatic This study’s limitations are that just three air scaler
extractions, wisdom tooth extractions, tori removal, inserts were evaluated, and therefore the results
endodontic post removal, calculus and caries cannot be extrapolated to other air scaler devices
removal. Because sonic instruments are driven by and inserts. Given that the air scaler works with the
air compression, they easily connect to an existing dental unit’s air supply, and these vary among dental
dental unit. There is no additional purchase required units, further evaluations are required with different
for an external motor, or an external irrigation air and power settings.
source [15]. This helps to minimize the cost incurred
by the dentist. It is an appropriate instrument for 5. CONCLUSION
those practitioners who are concerned with heat
generated, while treating osseous tissues. Osseous site preparation can be achieved with the
Other devices, such as piezosurgery have been air scaler; different air scaler inserts may be utilized
utilized for dental osteotomy procedures. without inducing significant thermal changes in the
Piezosurgery has not only been applied in dentistry, bone, as long as the conditions remain within the
but also in cranial and spinal surgery. limits of the above experimental set-up.
There are vast differences between piezosurgery
CONFLICT OF INTEREST
and air scaler instruments. Piezosurgery conducts
“piezoelectric vibrations”. Piezosurgery operates at None declared.
a much higher frequency (between 20,000 – 25,000
Hz) than sonic instruments (average of 6,000 Hz). AUTHOR CONTRIBUTIONS
It must be purchased as a separate device with a
separate motor and irrigation source. For this reason, DM, GER: Concept. DM, GER, SL, KK: Protocol. DM, SL, GER, FJ: Data
there is a significant cost difference between an air gathering and analysis. DM, RDG, KK, GER: Manuscript revision.
scaler and a piezosurgical unit.
Both air scalers and piezosurgery have been utilized ACKNOWLEDGMENTS
in dentistry. Each instrument has the advantage None.
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Dana M. MARZOCCO
DMD, Clinical Assistant Professor
Department of Prosthodontics and Digital Technology
Stony Brook, New York, USA
CV
Dr. Dana M. Marzocco works in private practice in New Hyde Park, New York. Her practice is limited to Prosthodontics. She holds a
faculty position as a Clinical Assistant Professor at the Stony Brook University, School of Dental Medicine, located in Stony Brook,
New York. In addition, Dr. Marzocco lectures on various implant and restorative topics.
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Questions
Original Articles
1. The Air scaler device operates using compressed air at a frequency of:
qa. 2000 Hz;
qb. 4000 Hz;
qc. 6000 Hz;
qd. 8000 Hz.
2. If temperature (oC) were to increase during a procedure, the operator would be
concerned. How many degrees of an increase would be a concern?
qa. 8 degrees;
qb. 10 degrees;
qc. 12 degrees;
qd. 15 degrees;
3. An Air scaler device can be utilized in which of the following procedures?
qa. Sinus augmentation;
qb. Harvesting bone;
qc. Osteotomies;
qd. All of the above.
4. Previous studies have shown that heating osseous tissue over 50 0C for a duration of
time has induced in vitro necrosis. After what amount of time does the necrosis occur?
qa. 30 seconds;
qb. 45 seconds;
qc. 1 minute;
qd. 2 minutes.
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