Comparation of the eutectic mixture of lidocaine/prilocain versus benzocaine gel in children

doi:10.4236/ojst.2011.13014

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Open Journal of Stomatology, 2011, 1, 84-91

doi:10.4236/ojst.2011.13014 Published Online September 2011 (http://www.SciRP.org/journal/OJST/ OJST

Published Online September 2011 in SciRes. http://www.scirp.org/journal/OJST

Comparation of the eutectic mixture of lidocaine/prilocain

versus benzocaine gel in children

Ana Maria Leyda1, Carmen Llena2*

1Private practice in Pediatric Dentistry, Valencia, Spain;

2Department of Stomatology, University of Valencia, Valencia, Spain.

Email: *[email protected]

Received 2 June 2011; revised 15 August 2011; accepted 25 August 2011.

ABSTRACT

Obje ctive: To compare the anesthetic effect of a non

commercial eutectic mixture of 4% lidocaine/

prilocaine (PLO 4%) and 20% benzocaine gel (Hur-

ricaine®), as topical anesthetic, prior to inferior al-

veolar nerve block and buccal infiltration anesthesia

in 5 - 12 year old children. Study design: Infiltrative

anesthesia was applied in 50 children, divided in two

groups (n = 25) using PLO 4% and Hurricaine® as

topical anesthesia prior to infiltration. Physical reac-

tions were registered using the Sound-Eyes-

Motor Scale. Physiological changes expressed by ar-

terial pressure and heart rate. Subjective pain re-

sponse was scored on a Facial Image Scale. Physical

physiological and subjective response was related to

the type of topical anesthetic, age and sex using χ2

and Mann-Whitney U test. Results: Physical resp-

onses to puncture were similar and localized in the

state of comfort with both anesthetics. Girls showed

more ocular response than boys. Subjective pain

perception and physiological reactions showed no

anesthetic- or sex-related differences, except for

heart rate before and after the procedure which was

significantly higher in girls. Conclusions: PLO 4%

showed the same capacity as Hurricaine® in reduc-

ing pain response to needle puncture. Girls ex-

pressed more needle puncture-related pain than boys.

The young children showed most prior comfort and

less discomfort to the puncture than older children.

Keywords: Lidocaine; Prilocaine; Benzocaine; Topical

Anesthetics

1. INTRODUCTION

In-office dental procedures are associated with discom-

fort and pain for most people. For the part of the popula-

tion which has to v isit the dentist, this association g ener-

ates fear and anxiety. If the patient is a child, controllin g

any discomfort and/or pain in dental procedures is fun-

damental and key to ensuring pleasant, safe and effective

treatment. For this purpose local anesthetics (LA) are

routinely used in pediatric dentistry [1].

However, the application of local anesthesia is often

frightening because it is associated with the use of nee-

dles, punctures and pain [2]. Together with cavity pre-

paration by turbine, the application of anesthesia is one

of the procedures which generate the greatest fear and

anxiety in pediatric patients and dentists themselves [3].

Local anesthesia is, however, a basic technique in han-

dling patient behavior because an effective anesthetic

technique will provide a relaxed patient, quality, effec-

tive work and satisfied parents.

To mitigate the sensation of discomfort produced by

needle insertion, various resources and procedures are

used [4-8]; some are psychological procedures, such as

distraction or suggestion, others physical procedures,

such as warming the anesthetic solution , administering it

very slowly (1 ml/min) to avoid the discomfort caused as

the anesthetic liquid distends the tissue and injecting the

anesthetics at a lower pressure of 306 mm/Hg [5]. Me-

chanical resources are also used such as generating other

simultaneous sensations to distract the child’s attention

and temporarily block the transmission of nociceptive

messages (Aδ and C fibres) or using needles with cali-

bers below N 27 because there is less perceived pain in

the mandibular block technique with smaller caliber

needles [6,7]. Another group of resources is based on the

prior surface anesthetic of oral mucosa by cooling,

transcutaneous electronic nerve stimulation or the use of

topical anesthetics (TA) [8].

The high concentrations of TA diffuse through the

epithelium and act on the mucosa nerve endings, block-

ing them. This decreases the painful sensation generated

by needle insertion. Currently, TA can be found in dif-

ferent presentations and compositions. However, they

still need to be combined with the other resources men-

A. M. Leyda et al. / Open Journal of Stomatology 1 (2011) 84-91 85

tioned above and even so, do not totally mitigate the

discomfort generated by needle insertion when applying

the local anesthetic [9].

Studies on topical anesthetics seek an agent which

meets a series of characteristics indicated as “ideal”. A

powerful, low dose TA is needed which is rapidly ab-

sorbed by the keratinized and non-keratinized mucosa,

remains in contact with the tissue to be anesthetized for a

long time to increase the depth of the action of the agent

and with characteristics which make it useful for pediat-

ric use: pleasant flavor, smell, color and texture [8].

These studies focus on the design and evaluation of

new TA preparations which meet these conditions [10]

and the present study has a similar aim, as its purpose is

to compare the anesthetic effect of a non commercial

eutectic mixture of 4% lidocaine and prilocaine (LPO

4%) as topical anesthetic on the oral mucosa, prior to

inferior mandibular and buccal nerve block anesthesia in

5-12 year old children, comparing the results with 20%

benzocaine gel (H u rri cai n e®).

2. MATERIAL AND METHODS

2.1. Subjects

The study population w as children be tween the ages of 5

and 12 who attended two private dental clinics in the

province of Valencia, Spain and the Dental Clinic at the

Faculty of Dentistry at CEU Cardenal Herrera Univer-

sity in the town of Moncada (Valencia, Spain) between

May and November 2008.

The sample was chosen using a consecutive sampling

system. Children who met the following criteria were

included in the study: at least 5 years old but under the

age of 13, needing clinical procedures which involved

mandibular nerve block and understanding Spanish. Ex-

clusion criteria were: having physical limitations which

might alter or require modifications in the local troncular

anesthesia, having psychological or sensorial limitations,

emotional limitations or a history of non collaborative

behavior with the dental treatment, having a systemic

pathology which contraindicated the use of local anes-

thetics and arriving for treatment with pain or dental

emergency.

2.2. The Anesthetic and the Needle

The anesthetics used in the study were 20% benzocaine

gel (Hurricaine®) and 4% lidocaine and prilocaine

ointment (LPO 4%), both prepared for this study in sin-

gle dose 0.5 gram tubes.

Local anesthesia was applied in all cases with dispos-

able sterile 25 mm 30 caliber dental anesthesia needles

(Normon jet plus®).

2.3. Measurement of Arterial Pressure, Heart

Rate, Physical Reactions and Subjective

Pain Perception

Patient physiology was measured using a hand-held

pulse oximeter (LTD810, Moretti) and a wrist device to

measure arterial pressure (Omrom, RX 3).

Physical reactions were measured on the Sound-Eyes-

Motor scale (Table 1) designed by Doctor Wright [11], a

scale frequently used in pediatric dentistry studies as it

enables an assessment of the relationship between pain

and the reactions the sensation of pain generates in the

patient’s eyes, movements and verbal expressions of

discomfort and also the degree of intensity of the sensa-

tion of pain [11].

Subjective pain perception was scored on the facial

images scale (FIS) [12] (Figure 1) which has 5 faces

with a number assigned from 1 to 5.1 coincides with the

face expressing the most happiness and 5 with the most

sadness.The intermediate numbers express intermediate

emotions between these two. Scoring is towards which

face the child most identifies with at that moment [12].

2.4. Registered Variables

The variables registered on the patient record were: sex,

age, clinical center, variables used to evaluate patient

physical reactions to puncture on the Sound-Eyes-Motor

scale, variables to record each patient’s subjective per-

ception of puncture on the Facial Images Scale, variables

related to physiological changes; heart rate, recorded at

the beginning of the session, at the moment of puncture

and arterial pressure recorded at the start and end of the

session.

2.5. Procedures

In all the patients the process of adapting to the dental

clinic was respected and treatments were progressively

introduced by order of difficulty, but in all cases the ap-

pointment included in the study was the first mandibular

nerve block done on the patient .

The type of topical anesthesia applied to each patient

was chosen alternatively by the operator, without bear-

ing in mind age and sex of the patients. All odd-num-

bered patients in the study received 20% benzocaine gel

and all even-numbered patients received the LPO 4%.

All the anesthesia was carried out by the same operator

unifying the manner of applying the injection and the

pre- and post-injection instructions and information

given to the patients. A prior study was carried out in 10

patients with the same characteristics to systematize and

protocolize the process.

We take in mind ethical considerations of Helsinki

declaration in 1975 revised in 2000. Before the start of

the session and after checking that the child met the cri-

A. M. Leyda et al. / Open Journal of Stomatology 1 (2011) 84-91

Table 1. Sound-Eyes-Motor scale [12].

Observations 1.- Comfort 2.-Slight discomfort 3.- Moderate pain 4.-Pain

Sound No sounds

indicating pain Non specific sounds which may

indicate pain. Specific verbal complaints

raising voice. Verbal complaints

indicating intense pain.

Eyes No ocular signs of

pain

 Eyes wide open.

 Shows concern.

 No tears.

 Watery eyes.

 Blinking eyes.  Crying.

 Tears rolling

down the face.

Motor

 Relaxed hands

 Body

apparently relaxed.

 Hands show stress or tension.

 Grasps hold of chair.

 Muscular tension.

 Arm or body movements

with no aggressive intention

 Physical contact.

 Pulling faces or grimacing.

Hand movement for

aggressive contact.

Figure 1. Facial image scale [13].

teria for inclusion in the study, the father, mother or

guardian was given an information sheet and a verbal

explanation by the operator. After the information, in-

formed consent was requested and when signed was

added to the patient data record card.

When the patient was comfortably seated in the dental

chair, the operator asked about his/her level of pain and

feeling of comfort at that moment, the assistant took the

arterial pressure and checked heart rate with the pulse

oximeter. Then the patient was given the necessary in-

structions and information about all procedures and

placed in the supine position in the dental chair. The

operator dried the area for topical anesthetic with sterile

gauze for 60 seconds to eliminate the saliva and mucins

which cover oral mucosa and the keratinzed layer of the

epithelium was swabbed to favor subsequent TA absorp-

tion. While the operator dried the mucosa, the assistant

collecte d the con tent of the s ingle dose of TA on a swab.

The operator applied the TA on the dry and swabbed

area for 2 minutes, placing an aspirator in lingual side of

the jaw to prevent TA contact with saliva and movement

in the place of application. After the established time, the

area was washed with abundant water to eliminate TA

remains.

Local anesthesia was administered using the distrac-

tion technique, preventing the patient from seeing the

needle. The puncture was made with a vibrating move-

ment of the cheek; at that moment the assistant recorded

the heart rate marked on the pulse oximeter. This value,

together with ocular, motor or verbal reaction generated

at the moment of the puncture, was recorded on the card.

On finishing injection of local anesthetic, the pulse oxi-

meter was withdrawn from the patient’s finger and the

patient was allowed to rinse his/her mouth. When the

treatment had finished, the operator asked the patient

again about his/her level of pain and feeling of comfort

at that moment, and the assistant took his/her arterial

pressure. All the values were recorded on the card.

2.6. Statistical Analysis

Data were analyzed using SPSS 15.0 software (SPSS,

Inc, Chicago, Ill); a descriptive analysis of the results

was made. Age was recoded in two groups: children

from 5 to 8 years old, and children from 9 to 12 years

old. The variables for physical reactions and the patient’s

subjective sensation and the type of anesthesia were

compared with recoded age, sex and type of anesthetic

using the Chi-Square test. Mann-Whitney’s U test was

used to relate physiological reactions with sex, recoded

age and type of anesthesia, for a confidence level of

95%.

3. RESULTS

3.1. Sample Description

Of the 53 patients chosen to take part in the study, 3

were not included because of a background of disruptive

behavior in office, the three were girls and so a total of

50 individuals took part in the study: 24 males (48%)

and 26 females (52%) between the ages of 5 years and

one month and 12 years and 11 months, with an average

A. M. Leyda et al. / Open Journal of Stomatology 1 (2011) 84-91 87

age of 8 years and 5 months (standard dev iation = 2.29).

During treatment, half the patients received benzocaine

gel as TA and the ot her half, LPO 4%.

Physical reactions to puncture were grouped accord-

ing to the three variables in the sound-eyes-motor scale.

For the variable sound, 90% (45) of the participants had

expressions compatible with well being; of the remain-

ing 10%, 4 had expressions compatible with slight dis-

comfort and one with moderate pain. For the variable

“eyes”, 90% (45) of the patients had reactions compati-

ble with well being; of the remaining 10%, 4 showed

reactions compatible with slight d iscomfort and one with

moderate pain. Finally, for the variable “motor”, 86%

(43) of the patients had reactions compatible with well

being; of the remaining 14%, 4 showed reactions com-

patible with slight discomfort and 3 with moderate pain.

The patients’ own perception of well being and pain,

collected on the facial image scale gave the following

results: 86% of the patients (43) felt very well when they

sat down on the dental chair and had no pain (value 1 on

the scale). The remaining 14% (7) felt simply well

(value 2 on the scale). At the end of the session 74% of

the patients (37) felt v ery well and without pain (value 1

on the scale); while 22% (11) felt simply well (value 2

on the scale) and 4% felt not well (value 3 on the scale).

3.2. Relationship between Anesthetic and

Physical Reactions

The variables registered on the sound-eyes-motor scale

showed no significant differences in relation to the an-

esthetic used with 90% in the situation of comfort (Table

2).

3.3. Relationship between Sex and Physical

Reactions

Analysis by sex, shows a greater motor, ocular and ver-

bal reaction to puncture in females than males, and ac-

quired statistical significance in the variable “eyes”

where it was found that males experience significantly

greater comfort than females (p = 0.03) (Table 2).

3.4. Relationship between Age and Physical

Reactions

Using the “sound, eyes, motor” scale for the expression

of discomfort through sounds, no 5 - 8 years old children

showed discomfor t after punctur e, but 21 .1% (4) of the 9

- 12 years old children expressed a uncomfortable per-

ception through unspecific sounds (p = 0.017).

3.5. Relationship between Anesthetic and

Subjective Perception of Pain

Comparison of the two TA, in relation to the subjective

perception of pain and comfort recorded by applying the

facial image scale at the beginning and end of treatment

gave practically the same results, mainly located in the

state of comfort (Table 3).

3.6. Relationship between Sex and Subjective

Perception of Pain

The results were also very similar for males and females

mainly located in th e state of comfor t (Table 3).

3.7. Relationship between Age and Subjective

Perception of Pain

Depending on the age of patients, we found a significant

association for comfort perception and pain, through the

pain facial scale used; so, 96.98% of the 5 - 8 years old

children (30) felt very well and without pain when sited

at the clinical chair (score 1 from the scale); the rest,

3.2% (1), felt simply well (score 2); while in the group

of 9 - 12 years old, 68.4% of the ch ild ren showed a scor e

1 and 31.6% a score 2 (p = 0.009).

Table 2. Comparison by type of anesthestic and sex of the Sound-Eyes-Motor scale’s scoring (significant value in bold).

n Comfort Slight discomfort Moderate pain p

SOUND

LPO4% 25 23 (92%) 1 (4%) 1 (4%) 0.52

Hurricaine 25 22 (88%) 3 (12%) 0

Male 24 23 (95.8%) 1 (4.2%) 0 0.34

Female 26 22 (84.6%) 3 (11.5) 1 (3.8%)

EYES

LPO4% 25 23 (92%) 2 (8%) 0 0.62

Hurricaine 25 22 (88%) 2 (8%) 1 (4%)

Male 24 24 (100%) 0 0 0.02

Female 26 21 (80.8%) 4 (15.4%) 1 (3.8%)

MOTOR

LPO4% 25 22 (88%) 1 (4%) 2 (8%) 0.51

Hurricaine 25 21 (84%) 3 (12%) 1 (4%)

Male 24 23 (95.8%) 1 (4.2%) 0 0.14

Female 26 20 (76.9%) 3 (11.5%) 3 (11.5%)

A. M. Leyda et al. / Open Journal of Stomatology 1 (2011) 84-91

Table 3. Subjective perception of pain using the “Facial Image Scale” by type of anesthetic and sex.

n 1 2 3 4 5 p

INITIAL PERCEPTION

LPO4% 25 21 (84%) 4 (16%) 0 0 0

Hurricaine 25 23 (88%) 3 (12%) 0 0 0 0.50

Male 24 22 (91.7%) 2 (8.3%) 0 0 0

Female 26 21 (80.8%) 5 (19.25%) 0 0 0 0.24

FINAL PERCEPTION

LPO4% 25 20 (83%) 4 (16%) 0 0 0

Hurricaine 25 17 (68%) 7 (28%) 1 (4%) 0 0 0.36

Male 24 18 (75%) 5 (20.8%) 1 (4.2%) 0 0

Female 26 19 (76%) 6 (24%) 0 0 0 0.57

3.8. Relationship between Anesthetic and

Arterial Pressure Modification

The initial and final measurement of arterial pressure

provided six values for each patient: systolic pressures

(initial and final) and the difference between the two;

two diastolic pressures (initial and final) and the differ-

ence between the two. After the procedure a clear modi-

fication of arterial pressure was observed but with no

significant differences between them (Table 4).

3.9. Relationship between Sex and Arterial

Pressure Modification

In relation to sex, patients of both sexes experienced

similar modifications in arterial pressure (Table 4).

3.10. Relationship between Anesthetic and Heart

Rate Modification

Analysis of heart rate modification on puncture gave

similar results. After the procedure a clear modification

of heart rate was observed but with no significant dif-

ferences between them (Table 5).

3.11. Relationship between Sex and Heart Rate

Modification

Difference between initial and final heart rate was sig-

nificantly higher in females (p = 0.04) (Table 5).

4. DISCUSSION

Although currently the effectiveness of TA in reducing

pain associated to intraoral injection of LA is much de-

bated, it is certainly much used in pediatric dentistry

[13].

Multiple factors are involved in pain perception, in-

cluding psychological factors such as personality, fear,

anxiety and the sensation of control over pain producing

agents or pain itself [2].

The results of this present study sho wed no difference

between the puncture pain felt and perceived with the

two TA studied.

20% Benzocaine gel is an ester-type anesthetic, with a

fast onset of action of approximately 3 0 second s [13,14],

a pleasant taste, a longer duration than other TA and a

low level of systemic absorption making it safe for use

in children [11]. However, its main disadvantage is low

bioadhesivity [4,15,16].

LPO4% is a non commercial eutectic mixture of 4%

lidocaine and prilocaine. Both these anesthetics, which

belong to the amide family, are less likely to provoke

allergic reactions than ester anesthetics and are ex-

tremely similar to the anesthetic used for infiltration an-

esthesia (2% lidocaine with epinephrine at 1:100,000),

also an amide. The galenic formula of LPO4% is

achieved with high occlusive, self-emulsifying bases,

thanks to the inclusion of ethoxylated lanolin and a

commercialized cosmetic base oil in water emulsion. It

is a greasy product which waterproofs the mucosa, fa-

voring greater localization and concentration of the

product in the area to be anesthetized. The euctectic

mixture of lidocaine and prilocaine significantly in-

creases the anesthetic power of the two components in-

dividually and solves the problem of solubility in these

anesthetic molecules so they can be included in their

most effective but least soluble base form, the only form

which can cross the nervous fiber membrane, and so pKa

must be greater than 7.4. The topical anesthetic “LPO4%”

has a pH of 8.4 [13]. Its pink color and strawberry-

pineapple taste make it acceptable to the pediatric popu-

lation [16]. As LPO4% is a non commercialized anes-

thetic preparation there are no previous studies on its

effectiveness in comparison to other TA for the same

uses. In contrast, there are many studies on benzocaine

gel as it is currently the most popular topical anesthetic,

the most used and the most recommended in general and

pediatric dentistry [13, 16] as it is well accepted by chil-

dren and professionals.

Studies in children show in some cases a slight supe-

riority of 20% benzocaine gel over other agents [13,17].

A. M. Leyda et al. / Open Journal of Stomatology 1 (2011) 84-91 89

In contrast, some studies show greater effectiveness

against pain of other agents, in particular 20% lidocaine

patches [16]. Other studies found that 20% benzocaine

gel was effective but not more than the other agents

which it was compared with [9,14]. This present study

can be included in this group of studies as it compares

the effectiveness of reducing injection pain of 20% ben-

zocaine gel and the eutectic mixture of 4% lidocaine and

prilocaine in a group of children between the ages of 5

and 12. The authors found no objective evidence for the

greater effectiveness of either of the two agents in re-

ducing needle insertion pain.

Table 4. Arte ria l pre ssure changes by type of anesthetic an d se x. ISP: initaial systolic presure, FSP: final systolic presure, IDO: initial

diastolic presure, FDP: final diastolic presure.

n Mean SD p

LPO4% 25 54.60 13.9

Hurricaine 25 58.90 16.38

0.42

Total 50 56.75 14.95

Male 24 56.50 16.74

Female 26 57.13 12.88

0.53

ISP

Total 50 56.75 14.95

LPO4% 25 54.00 9.62

Hurricaine 25 60.00 22.22

0.73

Total 50 57.00 16.95

Male 24 60.75 20.02

Female 26 51.38 9.45

0.11

FSP

Total 50 57.00 16.95

LPO4% 25 97.10 14.34

Hurricaine 25 90.60 11.99

0.18

Total 50 93.85 13.29

Male 24 92.00 15.29

Female 26 96.63 9.85

0.37

IDP

Total 50 93.85 13.29

LPO4% 25 98.40 12.25

Hurricaine 25 92.00 18.57

0.24

Total 50 95.20 15.66

Male 24 99.00 18.40

Female 26 89.50 8.50

0.13

FDP

Total 50 95.20 15.66

LPO4% 25 –0.60 11.87

Hurricaine 25 1.10 18.65

0.67

Total 50 0.25 15.24

Male 24 4.25 12

Female 26 –5.75 18.32

0.16

FSP-ISP

Total 50 0.25 15.24

LPO4% 25 1.30 10.28

Hurricaine 25 1.40 28.02

0.65

Total 50 1.35 20.54

Male 24 7.00 22.05

Female 26 –7.13 15.64

0.14

FDP-IDP

Total 50 1.35 20.54

A. M. Leyda et al. / Open Journal of Stomatology 1 (2011) 84-91

Table 5. Heart rate modification by type of anesthetic and sex IHR: initial hearth rate, FHR: final heart rate.

n Mean SD p

LPO4% 25 80.90 9.32

Hurricaine 25 83.70 14.97

0.18

Total 50 82.30 12.22

Male 24 82.75 10.00

Female 26 81.63 15.73

0.64

IHR

Total 50 82.30 12.22

LPO4% 25 91.70 18.99

Hurricaine 25 92.80 12.77

0.27

Total 50 92.25 15.76

Male 24 88.92 11.09

Female 26 97.25 20.82

0.23

FHR

Total 50 92.25 15.76

LPO4% 25 10.80 17.56

Hurricaine 25 9.10 13.49

0.85

Total 50 9.95 15.27

Male 24 6.17 10.84

Female 26 15.63 19.68

0.23

FHR-IHR

Total 50 9.95 15.27

Although our study shows no objective evidence of

greater effectiveness of LPO4% than Hurricaine® in

reducing needle insertion pain; it was not found to be

less efficient and, therefore, more studies are required to

analyze other parameters such as greater safety, as it is

fully similar to the anesthesia used for infiltration anes-

thesia and has a greater capacity to waterproof the mu-

cosa favoring better localization and concentration of

product in the area to be anesthetized, preventing it from

being mixed with saliva. This would solve the greatest

problem found with 20% benzocaine gel which is the

lack of bioadhesivity to the oral mucosa which generates

movement from the site of application to the surrounding

mucosa, reducing the anesthetic effect on the tissue and

sometimes causing patient discomfort [4,15,16]. Another

possible advantage of LPO4% is its pink color and

strawberry-pineapple taste which would favor accep-

tance by the pediatric population.

Analysis of the data has shown an interesting rela-

tionship between sex of the participants and their reac-

tion to puncture of the mucosa previously treated with

TA, with more intense ocular reaction in females than

males. In our study, 5 of the 26 girls showed ocular and

motor expressions which did not coincide with comfort,

and 4 of them were between the ages of 7 and 9. No boy

at that age showed any level of discomfort during the

local anesthesia procedure.

The children between 5 and 12 years old show typical

characteristics of this stage in the different areas of de-

velopment, such as desire for productive work, thereby

increasing feelings of competition; children are afraid of

the imaginary, of bodily harm, loss of image and dete-

riorated self-esteem. They are intensely preoccupied and

anxious about imaginary rather than real causes.

Related to dental fear, differences between sexes seem

to be inexistent, at least in the occidental societies, al-

though studies show different results, sex and age are in

fact co-factors modulated by other variables such as the

patient’s culture, socio-economic situation, etc. In fact,

only after reaching certain ages do differences in behav-

ior and anxiety levels among girls and boys become

evident [18,19]. Taylor et al. compared the behavior of

boys and girls and only after the age of 7 and during the

application of local anesthesia did they find that boys

showed fewer expressions of discomfort and negative

behaviors than gi rl s [2 0] .

Studies concluded that girls showed more fear than

boys. Not that they felt more fear, but that they showed it,

because boys behave better than girls when they are

given strict instructions about how to behave [21],

A. M. Leyda et al. / Open Journal of Stomatology 1 (2011) 84-91 91

showing that girls had significantly higher levels of den-

tal anxiety than boys even in adolescent patients with

greater levels of personal maturity [22].

5. CONCLUSIONS

As a result of this study we can conclude that LPO4%

was as capable as Hurricaine® in reducing pain gener-

ated by needle puncture for local anesthesia infiltration.

When faced with needle puncture for local infiltration

anesthesia by mandibular and buccal nerve block in 5 to

12 years old, girls expressed more pain by ocular ex-

pression than boys and a significant increase in heart rate

was found in girls at the end of the therapeutic treat ment.

By age, children from 9 to 12 years old expressed more

discomfort by sound expression than children from 5 to

8 years old. In the same way the younger children ex-

pressed more wellness before the procedure than older

children.

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