The Effect of Electrosurgery on Alveolar Bone*

R. Azzi.f E. B. Kenney4§ T. F. Tsao|| and F. A. Carranza, Jr4§

the facial marginal alveolar bone of dogs was exposed with a full-thickness flap and
touched by an activated electrosurgery electrode for periods of 0, 1, 5 and 10 seconds.
Microscopic results were evaluated after periods ranging from 0 hours to 28 days. Various
electrode exposure times produced similar changes in bone and periodontal ligament. The
extent of the destruction was greater than that found in surgical areas not exposed to
electrosurgery; healing and remodeling phases were also delayed in the electrosurgical sites.

One of the dangers of electrosurgery as a modality in cases it is difficult to identify the electrosurgical tech-
periodontal surgery is the possibility of inducing areas of nique used. The present study was designed to evaluate
bone necrosis if the electrode touches the bone acciden- the effect of direct electrosection on the alveolar process.
tally.1 Glickman and Imber2 have shown in dogs that MATERIALS AND METHODS
when a shallow gingivectomy procedure is used there is
little difference in the tissue response between incision Fifteen mongrel dogs were used for this investigation.
with a filtered, fully rectified, undampened electrosur- A baseline of gingival health was established by initial
gery technique and a conventional scalpel. However, scaling and prophylaxis, followed by a 0.2% Chlorhexi-
when deep incisions are used the result is bone necrosis dine gluconate application twice weekly for the duration
leading to reduction of bone height at 6 weeks and 12 of the experiment. In the initial scaling and all subse-
weeks post-surgery. Pope3 found that a similar type of
quent procedures, the dogs were anesthetized by intra-
electrosection used for gingivectomies in dogs resulted in venous Nembutal. Chlorhexidine application was done
increased numbers of osteoclasts and decreased activity without anesthesia.
of osteoblasts at 4 days post-surgery. Similarly, Nixon et After adequate anesthesia all dogs underwent the fol-
al.,4 using guinea pigs with an electrosection incision lowing surgical procedure: Registration notches were
through the gingiva to the periosteum, found at 12 hours made in the teeth with a M> round bur in a high-speed
tissue necrosis and destruction of the periosteum. Histo- handpiece. The gingival height and the pocket (sulcus)
logical evaluation showed that by 24 hours there were depth were measured from this point. A full thickness
empty lucunae in the alveolar process with degeneration periodontal flap was done in the facial aspect of the
of osteocytes; this was even more extensive at 48 hours. lower anterior teeth, exposing the underlying bone. A
There was no increase in osteoclasts and no change in notch was made on the tooth immediately coronal to the
the bone marrow. bone in the center of the facial aspect.
In contrast to the above findings, Scheida et al.5 re- On the facial bone of four of the six incisors, the
ported that when exposed alveolar crest of dogs was electrode of an electrosurgery unit was applied for 0, I,
lightly brushed with an active electrosection electrode 5 or 10 seconds. The length of time was randomly
there were no significant clinical nor histologie changes changed in each case for the different teeth. The electro-
at 70 days.
surgical unit used was an Ellman model 90 FFP which
There are case reports of bone necrosis following the delivers a fully rectified, filtered electrosectioning cur-
use of electrosurgical techniques in humans but in these
rent. The machine was calibrated by adjusting the cur-
rent to the appropriate amount of electrosection, utilizing
*
This research was supported by UCLA Academic Senate Grant. a distant area of gingiva. The dial setting utilized for
t Formerly Postdoctoral student in Periodontics, UCLA. Present each dog was therefore calibrated for the tissues found
address: 125 Blvd. St, Germaine, Paris VI, France. in each animal. The range of dial settings for the 15 dogs
Section of Periodontics, UCLA School of Dentistry, Los Angeles,
tested was between 1.5 and 2.0. The inactive electrode
CA.
was placed on the dog's thorax.
§ Member, UCLA Dental Research Institute.
The animals were placed on a soft nutritionally-bal-
I Formerly Visiting Scholar, UCLA. Present address: Peking Med-
ical College, Peking, China. anced diet for 1 week and thereafter received a normal
96
Volume 54
Number 2 Effect of Electrosurgery on Alveolar Bone 97
hard pellet balanced dietj One dog was sacrificed im- Twenty-four Hours. The 1 day postsurgical sites where
mediately after the operation and others after 6 hours no electrosurgery was used had normal fiber arrange-

(three dogs) and 1, 2, 3, 7, and 14 days (two dogs each ment throughout the periodontal ligament space with
time) and 28 days (one dog). The lower jaw was sectioned small focal areas of vascular acute inflammatory
mesially to the cuspids, fixed in formalin, decalcified changes. The alveolar bone appeared normal in all as-
with EDTA, and prepared for histological study. Sem- pects. There was still evidence of inflammation into the
iserial faciolingual sections stained with hematoxylin and site of the initial incision of the flap.
eosin were used. The areas where the electric current had been applied
showed increased areas of cell degeneration and inflam-
RESULTS mation. Very few fibers were seen in the coronal one-
third of the periodontal ligament space (Fig. 1). It was
Zero Hours. Specimens showed a normal periodontal also obvious that the changes of inflammation and ne-
ligament space and normal alveolar bone. The incision crosis occurred in the middle one-third of the periodontal
was clearly demarcated with evidence of hemorrhage
along the outer surface of the alveolar process. No ligament. These areas showed focal destruction of peri-
differences could be seen between those areas where odontal ligament fibers and replacement with large blood
vessels and acute inflammatory exúdate. The apical one-
electrosurgery had been applied and those where no third of the periodontal ligament was normal in all
current had been used.
Six Hours. At 6 hours all specimens showed evidence sections. There did not appear to be any relationship
of hemorrhage and inflammation into the incision line between the changes seen and the duration of current
outside the alveolar process. applied. The alveolar crestal bone on its outer section in
In the surgical areas where no current had been ap- these experimental sites showed evidence of necrosis with
plied, there was evidence of acute inflammation in focal greater numbers of detached pieces of bone present on
the outer surface. The inner surface showed areas of
areas ofthe coronal one-third of the
periodontal ligament inflammation in direct contact with the alveolar bone,
space. Clearly demarcated fiber bundles could be seen
running from the cementum to the alveolar bone. In the
middle one-third of the periodontal ligament space, the
collagenous tissue of the periodontal ligament appeared
normal, except for very small areas of inflammation
around blood vessels. The apical one-third showed nor-
mal periodontal ligament space morphology. The crestal
alveolar bone was normal in its outer surface as well as
in the trabecular spaces and the alveolar bone surface.
The surgical areas where electrosection current had
been applied showed similar changes, not apparently
related to the duration of the current. The coronal one-
third of the periodontal ligament space showed large
areas of inflammatory cells, predominantly polymorpho-
nuclear leukocytes, surrounding blood vessels, and these
inflammatory areas replaced almost all of the connective
tissue fibers that made up the periodontal ligament.
There were areas of denatured collagen present through-
out the coronal one-third of the periodontal ligament
space. The inflammatory changes seen involved vasodi-
lation and infiltration with polymorphonuclear leuko-
cytes. The middle one-third of the periodontal ligament
space also showed large areas of inflammation replacing
the connective tissue fibers. The apical one-third was
normal in most sections. The alveolar bone in these
experimental sections showed areas of necrosis on the
outer surface. There were pieces of bone separated from
the alveolar crest and the surface bone in this area often
showed a dark blue staining quality. The inner surface
of the alveolar bone appeared normal and there was no
evidence of any changes in the marrow spaces.
Figure 1. Alveolar crestal area 24 hours after application of electrosection
for 5 seconds. Acute inflammatory exúdate replacing periodontal fibers
\ Purina Dog Chow. and areas of necrotic collagenfibers (magnification X 150).
 J. Periodontol.
98 A zzi, Kenney, sao, Carranza February, 1983

and there was beginning evidence in the marrow spaces previously with the inflammation present in focal areas
of osteoclastic activity and inflammation present around throughout the periodontal ligament space. The alveolar
blood vessels. bone at this time showed evidence of osteoclastic activity
Three Days. At 3 days postsurgery the areas where no on both the outer and inner surfaces. There was no
current had been applied again were essentially similar evidence of any changes in the marrow spaces.
to those seen previously. There were small focal areas of All the electrosection areas showed the same types of
inflammation associated with blood vessels throughout changes without respect to the amount oftime the current
the periodontal ligament space and the alveolar bone had been applied. The focal areas of inflammation
appeared normal in all aspects. throughout the periodontal Ligament space were seen in
The changes seen in the earlier time periods continued the coronal one-third; however, these were more predom-
to be obvious in all electrosurgical areas (Fig. 2). There inant in the middle one-third, where necrosis and inflam-
was replacement of the fiber apparatus in the coronal mation and areas of increased vascularity were seen to
one-third of the periodontal ligament space with inflam- be replacing the destroyed periodontal fiber apparatus
matory exúdate, which showed evidence not only of of the periodontal ligament (Fig. 3). The areas where
polymorphonuclear leukocytes but also of macrophages. inflammatory changes were seen in the periodontal lig-
There was also evidence of regenerating fibroblasts seen ament showed a background of cell debris around these
in this area. The middle one-third of the periodontal regions. There were increasing numbers of macrophages
ligament space showed even more severe areas of necro- as well as the polymorphonuclear leukocytes reported
sis and inflammation than those seen in the coronal one- previously. The apical one-third appeared normal in
third. The apical one-third was normal. The alveolar these sections. The alveolar bone changes at 7 days in
bone changes were similar. the experimental sections showed evidence of necrosis
One Week. The areas where no current had been on the outer surface with beginning osteoclastic activity
applied at 7 days showed the same pattern as reported present in a few sections. Osteoclasts were present in

Figure 2. Alveolar crest area 3 days after application of electrosection Figure 3. Middle third ofperiodontal ligament 1 week after application
for 5 seconds. There is an acute inflammatory exúdate in the line of of electrosection for 1 second, The periodontal ligamentfibers have been
incision outside the alveolar process. The periodontal ligament space is mostly destroyed and there is proliferation of blood vessels with an
occupied with blood vessels, cell debris and inflammatory cells. There are inflammatory exúdate of polymorphonuclear leukocytes and macro-
areas of necrosis in cresta! bone phages (magnification x 150).
(magnification X 40).
Volume 54
Number 2 Effect of Electrosurgery on Alveolar Bone 99

most sections along the inner surface of the alveolar (Fig. 4). The marrow spaces appeared to have few if any
bone. The marrow spaces showed areas of inflammation inflammatory cells and were basically normal.
with occasional osteoclasts present and increasing num- Four Weeks. Areas where no electrosurgery had been
bers of macrophages as well as polymorphonuclear leu- applied showed normal dense connective tissue fibers in
kocytes. all areas of the periodontal ligament. There were a few
Two Weeks. Areas where no electrosurgery had been focal areas of blood vessel proliferation in the middle
used showed that the inflammatory changes seen at one-third of the periodontal ligament space. The alveolar
earlier periods had become more vascular in nature and bone onthe outer and inner surfaces as well as in the
inflammatory exudates appeared to be diminished. marrow spaces showed evidence of osteoblastic activity.
There was evidence of osteoclastic activity on both the The areas where electrosurgery had been used again
outer and inner surface of the alveolar bone. were all similar as reported previously. There was evi-
Once again, the changes seen in the electrosurgical dence of proliferating fibroblasts in the coronal one-third
sites were not related to the duration of the current but of the periodontal ligament space with blood vessels
all showed areas of vascular proliferation with granula- being present in many areas. Areas of intact fibers run-
tion-type tissue replacing the normal fiber arrangement ning from the cementum to the alveolar bone were
in the coronal one-third of the periodontal ligament present in most sections. These same changes were seen
space. These same changes were also obvious in the in the middle one-third where there were small areas of
middle one-third of the peridontal ligament space while blood vessels surrounded by proliferating fibroblasts,
the apical third appeared to be normal. Osteoclasts were with fibers raruiing from the alveolar bone to the cemen-
present on both the outer surface of the alveolar bone tum. The apical one-third of these sections appeared to
and along the inner bony margin lining the tooth socket have normal periodontal ligament morphology. The
outer surface of the alveolar bone showed that there was
osteoblastic activity in most sections. However, there was
evidence of osteoclastic activity in the 10-second speci-
men and in general there was evidence of massive bone
remodeling in the most coronal portion of the alveolar
crest. The alveolar bone hning the periodontal ligament
space again showed evidence of dramatic bony changes
and remodeling. There was osteoblastic activity in most
sections as well as occasional areas of osteoclastic activ-
ity. The marrow spaces showed evidence of remodeling
with osteoblastic activity being the predominant change
seen.

DISCUSSION
The different times used to test the effect of electro-
surgery on alveolar bone ranged from 1 to 10 seconds.
Although in some of the 10-second specimens a definite
area of burnt bone was seen clinically, this difference
was not reflected in the histological findings.
The destruction induced by raising a mucoperiosteal
flap was seen in the sections from areas not subjected to
electrosurgery as limited to the coronal third of the
periodontal ligament. It consists of an initial acute in-
flammatory response followed by osteoclastic résorption
of the bone crest. By 4 weeks this activity had ceased
and was replaced by osteogenic remodeling.
The areas where the electric current had been applied
showed destruction extending to the middle third of the
ligament with areas of focal destruction of fibers. Under
the microscope, changes were similar regardless of the
Figure 4. Alveolar crest area 2 weeks after application of electrosection length of electrode application time. This points to the
for 5 seconds. There is evidence of repair in the coronal portions of the need to avoid any contact of the electrode with the bone,
periodontal ligament with blood vessels and fibroblasts being present. no matter how fleeting, since even brief contacts induce
There is a small area of relatively normal periodontal ligament fibers
(arrows). Apical to this, reparative tissue can be seen. Osteoclasts are considerable damage. The reasons for the lack of addi-
present on both the inner and outer surface of the alveolar process tional damage with increased contact time are not readily
(magnification X 80). apparent. It could be assumed that the initially burnt
 J. Periodontol.
100 A zzi, Kenney, Tsao, Carranza February, 1983

area acts, as a barrier for further penetration of the in analogous human clinical situations and is worthy of
damaging current. further investigation.
By 4 weeks areas of osteoblastic and osteoclastic activ- The ability of the periodontal tissues to heal is shown
ity could be seen, indicating a remodeling phase of by the osteoblastic activity seen at 28 days. At this time
healing. the periodontal fibers were also regenerated in those
It appears that the alveolar bone and periodontal areas where tissue destruction had occurred. This sup-
fibers are subject to necrosis as a result of direct contact ports the findings of Scheida et al.5 who showed resto-
of the alveolar crest with an active electrosection elec- ration of the periodontium in dogs at 70 days. It should
trode. The initial response of this injury is an acute be noted, however, that Glickman and Imber2 showed
inflammatory response which was apparent at 6 hours. in their study that while there was restoration of normal
This inflammatory response is much more than that seen periodontal tissues at 84 days, the electrosection areas
when no current is applied to the bone. The alveolar had significantly apical positioning of the entire peri-
process has bone necrosis on its outer surface while the odontal attachment apparatus.
inner surface initially appears normal. Over a period of The present study, as well as previous reports, have
time this initial inflammatory response evolves into a utilized dogs as experimental animals. It should be noted
more chronic inflammation with granulation tissue and that these animals tend to be more resistant to periodon-
repair eventually resulting in tissue healing. This is in tal damage than humans. It is apparent that even fleeting
agreement with previous animal studies which have contact of the active electrode with the alveolar process
shown that the initial necrosis and inflammation associ- induces bone résorption; therefore its use should be
ated with electrosurgery are eventually replaced by a limited to surgical techniques where contact with bone
healing phase. can be easily avoided.
The present study found that osteoclastic activity was REFERENCES
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changes seen in the periodontal ligament, would suggest study. / Periodontol 41: 142, 1970.
3. Pope, J. W.: Effect of electrosurgery on wound healing in dogs.
that patients on whom contact of electrosurgery elec- Periodontics 6: 30, 1968.
trodes on the alveolar crests have been made would be 4. Nixon, K. C, Àdkins, . F., and Keys, D. W.: Histological
more Likely to develop periodontal defects post-surgi- evaluation of effects produced in alveolar bone following gingival
incision with an electrosurgical scalpel. J Periodontol 46: 40, 1975.
cally. 5. Schieda, J. D., DeMarco, T. J., and Johnson, A. E., Jr.: Alveolar
The finding of significant tissue damage in areas of bone response to the electrosurgical scalpel. J Periodontol 43: 225, 1972.
the periodontal ligament distant from the application
point of electrosection may be due to electron flow along Send reprint requests to: Dr. F. A. Carranza, Jr., Section of Perio-
vascular channels. This destruction of the periodontium dontics, School of Dentistry, University of California, Los Angeles,
could result in increased mobility and patient discomfort Los Angeles, CA 90024.