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Original Article pISSN 2383-9309❚eISSN 2383-9317
J Dent Anesth Pain Med 2018;18(6):367-373❚https://doi.org/10.17245/jdapm.2018.18.6.367
Comparison of anxiety and pain perceived with
conventional and computerized local anesthesia
delivery systems for different stages of anesthesia
delivery in maxillary and mandibular nerve blocks
Kamal Aggarwal, Arundeep Kaur Lamba, Farrukh Faraz, Shruti Tandon, Kanika Makker
Department of Periodontics, Maulana Azad Institute of Dental Sciences, New Delhi, Delhi, India
Background: Fear of local anesthesia (LA) is a significant impediment to dental care as many patients delay
or avoid treatment to avert pain. Computer-controlled local anesthetic delivery system (CCLAD), with constant
and controlled rate of flow, present a painless alternative. The present study aimed to compare anxiety and
pain perceived with conventional and computerized systems, for different stages of anesthesia delivery when
administering various nerve blocks.
Methods: One hundred patients requiring bilateral LA participated in the study. One side was anesthetized
using one system and the contralateral side was anesthetized using the other, in two separate appointments.
Patients assigned anxiety scores on a 5-point scale and used the visual analogue scale (VAS) for pain determination
at needle insertion, during delivery of anesthetic solution, immediately after injection, and at the end of the
periodontal procedure. Each patient’s preference for the delivery system of future injections was also recorded.
Results: Patients reported significantly lower anxiety levels with CCLAD compared to the syringe. Significantly
lower mean VAS scores for anesthesia deposition, pain immediately after, and at the end of the periodontal
procedure were also noted. However, pain at needle insertion was comparable between the two systems, with
no statistical significance. Overall, 64.4% patients preferred CCLAD for future anesthesia.
Conclusion: Lower pain perceived with CCLAD and higher preference for the system suggest that CCLAD
should replace conventional syringes to allow pain-free dental treatment.
Keywords: Computer-controlled Local Anesthetic Delivery System ; Local Anesthesia; Pain; Pain Perception;
Visual Analogue Scale.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License
(http://creativecomm ons.org/licenses/by-nc/4.0/) which p ermits unrestricted non-com mercial use, distrib ution, and reproduc tion in
any medium, provided the original work is properly cited.
Received: October 9, 2018•Revised: November 5, 2018•Accepted: November 26, 2018
Corresponding Author: Kamal Aggarwal, Department of Periodontics, Maulana Azad Institute of Dental Sciences, New Delhi, Delhi, 110002, India
Tel: +91-9999685798 E-mail: kamal208maids@gmail.com
Copyrightⓒ 2018 Journal of Dental Anesthesia and Pain Medicine
INTRODUCTION
The fear of local anesthesia (LA) is a significant
impediment to dental care, as many patients delay or
avoid treatment to avert pain. Nearly 20-23% of
population is highly anxious about their dental treatment
[1]. Pain can result from the mechanical trauma of needle
insertion, or from the sudden distension of the tissues
caused by rapid deposition of LA from the syringe [2].
Using a conventional hypodermic syringe, the dentist
must simultaneously control the movement of the
penetrating needle and drug infusion variables. The
inability to precisely control both activities can com-
promise the injection technique, leading to painful
insertion or inadequate deposition. Moreover, the
conventional syringe is held with a palm-thumb grasp,
which is not ergonomic.
The first computer-controlled local anesthetic delivery
system (CCLAD) was introduced in 1997 as the Wand
Kamal Aggarwal, et al
368 J Dent Anesth Pain Med 2018 December; 18(6): 367-373
Fig. 1.
The visual analogue scale (VAS) used for evaluating the perceived
pain among patients.
Fig. 2.
The computer controlled local anesthetic delivery system.
(Milestone Scientific Inc., Livingston, USA) to improve
the ergonomics and precision of dental syringe. Its
lightweight handpiece can be held with a pen-like grasp,
which provides better tactile sensation. The operator can
accurately manipulate needle placement with fingertip
accuracy and deliver the solution with a foot-activated
control. The flow rate is computer-controlled and remains
constant. Continuous positive pressure delivers an
anesthetic drip that precedes the needle and provides a
painless path for needle insertion [3]. The disadvantages
associated with the system include high cost, complexity,
space needed to store equipment, and increased time for
LA administration [4,5].
Research on CCLAD is largely limited to pediatric
patients. There is paucity of literature on its use in other
fields of dentistry. The present study was undertaken to
evaluate pain and anxiety associated with conventional
syringe and CCLAD for nerve block LA, administered
for periodontal procedures. In particular, this study
compared pain associated with the two techniques during
different phases of local anesthetic delivery (at needle
insertion, during deposition of anesthesia, immediately
after deposition, and at the end of the periodontal
procedure).
METHODS
This is a prospective randomized split-mouth study.
Patients aged 18-65 years with periodontal disease,
requiring bilateral LA in the same arch, were recruited
for the study. Patients who are allergic to LA or any of
its components, medically compromised, smoking,
pregnant, lactating, or taking corticosteroids or non-
steroidal anti-inflammatory drugs were not included.
Written informed consent was obtained from participants,
in accordance with the Committee on Human Research
Guidelines, University of Delhi. The Institutional Review
Board number for the study was Maids/Perio/01/2011.
Anesthetic Injection Procedure: On the first appoint-
ment for periodontal therapy, the patient underwent a
sensitivity test for LA and was familiarized with the
scales used for evaluating anxiety and pain. Anxiety was
determined immediately prior to LA administration on a
5-point scale as follows: 0-no anxiety, 1-mild anxiety, 2-
moderate anxiety, 3- severe anxiety and 4- extreme
anxiety or panic [6]. The visual analogue scale (VAS)
was used for the evaluation of pain [7]. VAS was scored
on a 100-mm horizontal line with the left end marked
“no pain” and the right end “severe intolerable pain” (Fig.
1).
In each case of CCLAD, 2% lidocaine anesthetic
solution with 1:80,000 adrenaline (Lignospan SpecialTM,
Septodont, India) was used with a 30-gauge 1.25-inch
needle (Fig. 2). A disposable 30-gauge 1.25-inch needle
(Septoject, Septodont, France) was used for conventional
LA delivery via a dental syringe.
Types of injections used for the mandibular arch were
the inferior alveolar (IAN), long buccal (LB), and mental
(MN) nerve blocks. Types of injections used for the
Pain and anxiety with CCLAD
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Fig. 3.
Comparison of mean anxiety scores between the computer
controlled local anesthesia delivery system and conventional syringe.
Table 1.
Types and numbers of injections administered
Type of injection Number
Infraorbital nerve block 24
Posterior superior alveolar 28
Inferior Alveolar Nerve block 24
Greater palatine nerve block 20
Anterior Middle Superior Alveolar block 13
Mental nerve block 16
Long buccal nerve block 10
Total 135
Table 2.
Types of periodontal procedures performed after administration
of local anesthesia
Type of Periodontal therapy Number
Curettage 44
Flap surgery 26
Subgingival scaling 24
Gingivectomy 03
Implant surgery 01
Depigmentation 01
Abscess Drainage 01
Total 100
maxillary arch were the posterior superior alveolar (PSA),
infraorbital (IO), greater palatine (GP), and anterior
middle superior alveolar (AMSA) nerve blocks. The
volume of anesthetic solution injected was in accordance
with the procedure recommended by Malamed [8].
At the first appointment, anxiety was determined prior
to the injection. CCLAD or conventional syringe was
randomly selected and used to deliver LA to one side
of the arch. The patient was asked to rate the associated
pain on VAS at the following stages: during needle
insertion, during delivery of anesthetic solution, and
immediately after the injection. Pain was also assessed
at the completion of the periodontal procedure. Similarly,
at the second appointment, the contralateral side of the
arch was anesthetized for treatment using the other
anesthetic delivery system. Anxiety and pain were
recorded as above. The delivery system preferred by the
patient for future injection delivery was noted.
The data were analyzed using SPSS software version
17.0. Mann-Whitney U tests were used to compare the
anxiety and VAS scores obtained from the patients. The
significance level was set as 5%.
RESULTS
One hundred adults (44 males and 56 females) with
a mean age of 34.15 ± 18.92 years were selected from
the Outpatient Department of Periodontology, Maulana
Azad Institute of Dental Sciences according to the
inclusion and exclusion criteria and enrolled in the study.
In total, 270 injections (135 on each side) were
administered. Table 1 provides data on the numbers of
each type of injection. Periodontal procedures undertaken
included subgingival scaling, curettage, gingivectomy and
flap surgeries (Table 2).
The mean anxiety scores with conventional syringe and
CCLAD were 1.01 ± 1.02 and 0.78 ± 0.91, respectively,
indicating a significantly lower anxiety level in the
CCLAD group (P = 0.043) (Fig. 3).
For pain during needle insertion, the score for
conventional syringe was 16.67 ± 15.24. The mean pain
score for CCLAD was 13.53 ± 13.05, but the difference
was not statistically significant. However, a significantly
lower score for CCLAD was obtained, during drug
deposition. The VAS scores were 14.51 ± 15.40 and
11.24 ± 14.25 for conventional and CCLAD techniques,
respectively. The pain scores for immediately after the
injection were similar, with a significantly lower mean
pain score for CCLAD (3.86 ± 8.86) than conventional
syringe (6.23 ± 9.40). Lastly, pain reported at the
Kamal Aggarwal, et al
370 J Dent Anesth Pain Med 2018 December; 18(6): 367-373
Table 3.
Descriptive data of mean visual analogue scale scores
Stage of administration Conventional syringe CCLAD*
(WAND) Difference P value
Pain during needle insertion 16.67 ± 15.24 13.53 ± 13.05 3.14 0.076
Pain during drug deposition 14.51 ± 15.40 11.24 ± 14.25 3.27 0.053
Pain immediately after injection 6.23 ± 9.40 3.86 ± 8.86 2.37 0.000
Pain at completion of periodontal procedure 1.78 ± 4.51 0.96 ± 4.71 0.82 0.011
*: CCLAD: Computer Controlled Local Anesthetic Delivery System
completion of periodontal procedures was also lower in
CCLAD, and this difference was statistically significant
(1.78 ± 4.51 with conventional syringe; 0.96 ± 4.71 with
CCLAD; P = 0.011) (Table 3).
In total, 64.4% of patients preferred CCLAD and opted
for the same for any future injections; while 32.5%
preferred conventional syringes. Additionally, 2.9%
patients did not find any difference in the two delivery
systems.
DISCUSSION
Local anesthesia is the backbone of pain control in
dentistry. Its proper administration is the dentist’s greatest
aid in treating patients comfortably and in achieving
cooperation. However, administration of LA injection
produces anxiety and pain in patients. Therefore, research
has continued to develop new and better ways of
delivering adequate LA to improve patient comfort.
CCLAD was developed with this same aim. The
manufacturers hoped to minimize pain by delivering a
controlled volume of solution at constant pressure
irrespective of tissue resistance with a pre-puncture
technique and use of careful axial needle rotation [3]. The
present study aimed to evaluate anxiety and pain
perceived with CCLAD, and to compare it with the
conventional method of LA administration.
Anxiety level was significantly less when local
anesthetics was administered using CCLAD compared to
conventional syringes. The lower anxiety levels can be
attributed to the less frightening appearance of the device.
The loading of cartridge in CCLAD does not provoke
fear in patients as it does in the conventional syringes.
Technological advances have led to great dependency and
trust on machines. It could be that patients were less
anxious and more accepting knowing an advanced,
computerized machine was being used to achieve
anesthesia. Krochak and Friedman [6] reported a similar
observation in their patients who were successfully
desensitized against dental injections anxiety, using the
Wand. In contrast, Goodell et al. [9] observed less anxiety
with the syringe than CCLAD. The authors speculated
that the new and unfamiliar anesthesia device was perhaps
more fear provoking [9]. In another study, Tahmassebi
et al. [10] reported no statistical difference in anxiety
when comparing the two systems. This may be attributed
the study being conducted among children, who cannot
accurately and with absolutely determine anxiety levels.
The mean VAS score for needle insertion was lower
in CCLAD, but the difference was not statistically
significant. In previous studies, Yenisy [11] and Yesilyurt
[12] reported lower pain with CCLAD. Conversely,
Nusstein [13] reported similar pain on needle insertion
in both the systems when administered to anesthetize the
anterior middle superior alveolar nerve. It has been
speculated the computer-assisted injection systems create
a continuous positive pressure that delivers anesthetic
solution preceding the needle path, to eliminate dis-
comfort as the needle penetrates the tissue. This
pre-puncture technique could be the reason for lower pain
perceived with CCLAD. However, in the present study,
a significant difference was not obtained. It may be
speculated that the lack of difference may be associated
with same-sized needles being used in both systems.
Pain on LA deposition was significantly lower with
Pain and anxiety with CCLAD
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Fig. 4.
Pen-grasp used in the computer controlled local anesthesia delivery
system.
CCLAD. This is consistent with the findings of the
studies by Yenisy [11] and Nusstein [13]. Lower pain
may be attributed to the delivery of anesthetic solution
at constant pressure, which is rapidly absorbed by
surrounding tissues. A steady flow of 1 drop of anesthetic
every two seconds is maintained by the stepper motor
in the driver unit of CCLAD irrespective of the density
of tissues. In contrast, in the conventional syringe, manual
control does not allow consistent flow. The resistance
encountered when injecting into dense connective tissue
causes the operator to increase force on the syringe
plunger, thus increasing the anesthetic volume that
distends the tissues, thereby resulting in pain.
VAS scores for pain at the end of the periodontal
procedure also showed significantly lower pain with
CCLAD. This is in agreement with the findings of studies
by Asarch et al. [14], Gibson et al. [15], Allen et al. [16],
Fukayama et al. [17] and Palm et al. [18]. Reduced pain
may be attributed to a more accurate technique and
greater precision in the delivery of local anesthesia using
CCLAD [19]. It allows a pen-grasp that is easier to
manipulate and has a small headpiece for increased
visibility of the target site, which enables precise delivery
of the LA solution (Fig. 4). Additionally, CCLAD allows
easier aspiration during injection without a change in the
needle position; a problem frequently encountered with
conventional syringes.
A higher patient preference for the less painful CCLAD
was obtained in the present study. Nicholson et al. [20]
also reported high acceptance of CCLAD amongst both
dentists and patients.
Most of the studies on CCLAD have been conducted
among children. CCLA has been shown to decrease
disruptive behavior. However, in order to obtain more
reliable results and more accurate evaluation, the present
study selected adults as participants. In particular, this
study assessed pain at different stages of anesthetic
administration, whereas most studies in the literature
evaluated the experience overall and generally assessed
pain at the end of a procedure [16,17,20,21].
VAS was used to determine the perceived pain at
different stages of LA administration. Numerous metho-
dologies exist to assess pain. It is well recognized that
it is extremely difficult to quantify pain owing to its
subjective nature. VAS provides the advantage of un-
limited number of possible responses along with a simple
continuum [22].
One limitation of this study was the inability to
implement a double -blinded research design. Blinding
is not possible, because the operator would always be
aware of the significant difference between the two
injection systems during LA administration. In addition,
the patient would be able to hear the built-in beeping
sound of the CCLAD, even if their vision was restricted.
In conclusion, the results of the present study
demonstrated the advantages of CCLAD over the
conventional syringe for delivering LA, as evidenced by
the significantly lower anxiety and perceived pain among
patients, as well as higher preference for CCLAD.
Further studies using objective physiological markers of
pain, such as changes in heart rate and blood pressure,
may be useful for confirming the findings of this study.
AUTHOR ORCIDs
Kamal Aggarwal: https://orcid.org/0000-0002-0424-3312
Arundeep Kaur Lamba: https://orcid.org/0000-0001-5782-0614
Farrukh Faraz: https://orcid.org/0000-0003-1651-8077
Shruti Tandon: https://orcid.org/0000-0002-0524-099X
Kanika Makker: https://orcid.org/0000-0002-3954-6743
Kamal Aggarwal, et al
372 J Dent Anesth Pain Med 2018 December; 18(6): 367-373
FUNDING: This research did not receive any grant from
funding agencies in the public, commercial, or non-profit
sectors.
DISCLOSURE OF POTENTIAL CONFLICTS OF INTEREST:
The authors declare that they have no conflicts of interest.
ETHICAL APPROVAL: This article does not include any
animal studies. All procedures performed on human
participants were in accordance with the ethical standards
of the institutional research committee and the Helsinki
declaration.
INFORMED CONSENT: Written informed consent was
obtained from all participants.
REFERENCES
1. Locker D, Sharpiro D, Lidell A. Who is dentally anxious?
Concordance between measures of dental anxiety.
Community Dent Oral Epidemiol 1996; 24: 346-50.
2. Meechan JG, Howlett PC, Smith BD. Factors influencing
the discomfort of intraoral needle penetration. Anesth Prog
2005; 52: 91-4.
3. Friedman MJ, Hochman MN. A 21st century computerized
injection system for local pain control. Compend Contin
Educ Dent 1997; 18: 995-1003.
4. Palm AM, Kirkegaard U, Poulsen S. The wand versus
traditional injection for mandibular nerve block in children
and adolescents: Perceived pain and time of onset. Pediatr
Dent 2004; 26: 481-4.
5. Kandiah P, Tahmassebi JF. Comparing the onset of
maxillary infiltration local anaesthesia and pain experience
using the conventional technique vs. the Wand in children.
Br Dent J 2012; 213: E15.
6. Krochak M, Friedman N. Using a precision metered
injection system to minimize dental injection anxiety.
Compend Contin Educ Dent 1998; 19: 137-48.
7. Katz J, Melzack R. Measurement of pain. Surg Clin North
Am 1999; 79: 231-52.
8. Malamed SF. Handbook of local anesthesia. 4th ed. St.
Louis: Mosby; 1997. pp 191-218.
9. Goodell GG, Gallagher FJ, Nicoll BK. Comparison of
a controlled injection pressure system with a conventional
technique. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod 2000; 90: 88-94.
10. Tahmassebi JF, Nikolaou M, Duggal MS. A comparison
of pain and anxiety associated with the administration of
maxillary local analgesia with Wand and conventional
technique. Eur Arch of Paediat Dent 2009; 10:77-82.
11. Yenisey M. Comparison of the pain levels of computer-
controlled and conventional anesthesia techniques in
prosthodontic treatment. J Appl Oral Sci 2009; 17: 414-20.
12. Yesilyurt C, Bulut G, Taşdemir T. Pain perception during
inferior alveolar injection administered with the Wand or
conventional syringe. Br Dent J 2008; 10: 258-9.
13. Nusstein J, Lee S, Reader A, Beck M, Weaver J. Anesthetic
efficacy of the anterior middle superior alveolar injection.
Anesth Prog 2004; 51: 80-9.
14. Asarch T, Allen K, Petersen B, Beiraghi S. Efficacy of
a computerized local anesthesia device in pediatric
dentistry. Pediatr Dent 1999; 21: 421-4.
15. Gibson RS, Allen K, Hutfless S, Beiraghi S. The Wand
vs. traditional injection: a comparison of pain related
behaviors. Pediatr Dent 2000; 22: 458-62.
16. Allen KD, Kotil D, Larzelere RE, Hutfless S, Beiraghi
S. Comparison of a computerized anesthesia device with
a traditional syringe in preschool children.Pediatr Dent
2002; 24: 315-20.
17. Fukayama H, Yoshikawa F, Kohase H, Umino M, Suzuki
N. Efficacy of anterior and middle superior alveolar
(AMSA) anesthesia using a new injection system: the Wand.
Quintessence Int 2003; 34: 537-41.
18. Palm AM, Kirkegaard U, Poulsen S. The wand versus
traditional injection for mandibular nerve block in children
and adolescents; perceived pain and time of onset. Pediatr
Dent 2004; 26; 481-4.
19. Nicholson JW, Berry TG, Summitt JB, Yuan CH, Witten
TM. Pain perception and utility: a comparison of the syringe
and computerized local injection techniques. Gen Dent
2001; 49: 167-73.
20. Hochman M, Chiarello D, Hochman CB, Lopatkin R,
Pergola S. Computerized local anesthetic delivery vs.
Pain and anxiety with CCLAD
http://www.jdapm.org 373
traditional syringe technique: subjective pain response. NY
State Dent J 1997; 63: 24-9.
21. Loomer PM, Perry DA. Computer-controlled delivery
versus syringe delivery of local anesthetic injections for
theurapeutic scaling and root planing. J Am Dent Assoc
2004; 135: 358-65.
22. Price DD, Bush FM, Long S, Harkins SW. A comparison
of pain measurement characteristics of mechanical visual
analogue and simple numerical rating scales. Pain 1994;
56: 217-26.