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Year : 2021  |  Volume : 32  |  Issue : 3  |  Page : 288-291
Using nitrous oxide inhalation sedation for classical conditioning - An evaluative study

Department of Pediatric and Preventive Dentistry, ITS-CDSR, Ghaziabad, Uttar Pradesh, India

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Date of Submission14-Feb-2021
Date of Decision07-Jul-2021
Date of Acceptance23-Jul-2021
Date of Web Publication23-Feb-2022


Purpose: This study was undertaken to evaluate conscious sedation as a means of classical conditioning for managing paediatric dental patients. Methods: A total of 20 healthy children (American Society of Anesthesiologists I) aged 5–9 years with positive and definitely positive Frankel behaviour rating scale were evaluated. In the first appointment (A1) non-invasive treatment under nitrous oxide inhalation sedation was performed and oxygen saturation and pulse rate at 10%, 30% and 50% were recorded. In subsequent appointment (A2) same treatment was executed under 100% oxygen and recordings were taken. Behaviour was assessed using comfort scale. Results: No significant difference was observed in pulse rate, oxygen saturation and visual analogue scale whereas scores of comfort scale showed significant results. Conclusion: Once behaviour modification to dental treatment is achieved, subsequent visit can be undertaken even without sedation, giving oxygen as a placebo where patient is sensitized to nasal hood resulting in positive dental behaviour.

Keywords: Classical conditioning, Ivon Pavlov, nitrous oxide, pulse rate

How to cite this article:
Goyel V, Jain A, Mathur S, Malik M, Sachdev V. Using nitrous oxide inhalation sedation for classical conditioning - An evaluative study. Indian J Dent Res 2021;32:288-91

How to cite this URL:
Goyel V, Jain A, Mathur S, Malik M, Sachdev V. Using nitrous oxide inhalation sedation for classical conditioning - An evaluative study. Indian J Dent Res [serial online] 2021 [cited 2022 Aug 15];32:288-91. Available from:

   Introduction Top

One of the biggest challenges for any dentist is to treat a pediatric patient; as pediatric patient differs from adult patient not only psychologically but emotionally and physically as well.[1] The apprehension and anxiety child perceives during the treatment becomes a deterrent in delivering quality treatment.[2] To instil a positive attitude in children following dental visit is indeed a difficult task.[3]

Pediatric dentistry has over the years evolved the behaviour management techniques. Though innumerable researches have been undertaken, varied behaviour management techniques have been studied but ultimately there is no fixed formula that works on all the pediatric patients and even on the same patient at different appointments.[4] The American Academy of Pediatric Dentistry (AAPD) guidelines have divided the management approach for uncooperative children into basic and advanced while the basic behaviour guidance includes Tell Show Do, voice control, classical conditioning, positive reinforcement, and nitrous oxide (N2O) and oxygen inhalation analgesia: The advanced behaviour guidance includes protective stabilization and General Anaesthesia.

Both these kinds of techniques are equally important to alter the behaviour of an uncooperative child in the field of pediatric dentistry. However, it has been noted that there are more number of studies on pharmacological management techniques as compared to non-pharmacological techniques which have been addressed at the AAPD conference 2003.[5]

In this study, a combination of both these techniques was evaluated; quality dental treatment was instilled by doing classical conditioning of child and utilizing the concept of placebo effect in pediatric dental setup administrating N2O inhalation sedation in the first appointment followed by studying its effect as placebo in the subsequent appointments.

The term conscious sedation is defined as, “A medically controlled state of depressed consciousness that allows the protective reflexes to be maintained; retains the patient's ability to maintain a patent airway independently and continuously; and permits an appropriate response by the patient to physical stimulation or verbal command.”

Classical conditioning, also known as Pavlovian conditioning is learning through association and was discovered by Ivon Pavlov, a Russian psychologist in 1927 through his bell dog experiment. In simple terms, in this technique two stimuli are linked together to produce a new learned response in a person or animal.

A Placebo is usually defined as “an intervention designed to stimulate medical treatment, but it is not believed by the investigator to be a specific therapy for the target condition”. Sometimes it is discovered that the supposed “placebo treatment “is not an intervention at all. The explanation in such cases is that the patient's cognitive expectancy, that is, the patient's belief that the treatment will be effective, plays a vital role. When this happens it turns the inert placebo into effective treatment.[6]

In this study N2O inhalation sedation was used as treatment while oxygen was administered as a placebo in the subsequent appointment.

The objective of this study is that once the behaviour modification is achieved through classical conditioning via N2O, the patient accepts the treatment in the subsequent visits, even without the actual administration of inhalation sedation.

Notably, our knowledge is still in its infancy and is limited by the lack of studies designed to investigate the placebo effect on behaviour management to rule out positive behaviour from uncooperative child.

Thus, this study intended to explore this aspect.

   Material and Methods Top

This study was conducted in the Department of Pediatric and Preventive dentistry, with approval from ethical committee of the institute. The purpose of the study was explained and a written consent was obtained from the patients' parents who were willing to participate in the study.

20 healthy children (American Society of Anaesthesiologists; ASA I) aged five to nine years with 2, 3 and 4 Frankel behaviour rating requiring at least two restorations were selected for the study. N2O inhalation sedation was administered to these patients on their first appointment (A1) when one tooth was restored while in the second appointment (A2) the other tooth was restored under 100% oxygen alone. Pulse rate (PR), oxygen saturation (SPO2), visual analogue scale (VAS) and comfort scale (CS) were recorded for each patient at both the appointments.

Inclusion criteria

  • Children Aged between 5 to 9 years
  • Children with Frankl's behaviour rating score of 2, 3, 4
  • No prior dental experience
  • Children requiring dental treatment under N2O sedation
  • Children requiring at least two restorations.
  • Systemically healthy children (American Society of Anaesthesiologists Type I)

Exclusion criteria

  • Frankl's behaviour rating score of 1
  • Medically and developmentally compromising conditions

Statistical analysis

Sample size was calculated according to the following formula:

n = (σ1^2+ σ2^2) (Z_(1-α⁄2) + Z_(1-β))^2)/Δ^2

The notation of the formula is:

n = sample size of groups

σ1 = standard deviation of Group 1

σ2 = standard deviation of group 2

Z_(1-α⁄2) = two-sided Z value (e.g. Z = 1.96 for 95% confidence interval)

z_(1-β) = power = 80%

Δ = difference in group means

By placing all the values sample size turns out to be; 20

Parametric data was analysed with the help of means and standard deviation. Inter-group analysis was carried out with the help of Mann–Whitney test.

Hypothesis that were considered for the study:

  1. There is no significant difference between the appointments in influencing the SPO2
  2. There is no significant difference between the appointments in influencing PR.
  3. There is no significant difference between the appointments in influencing CS
  4. There is no significant difference between the appointments in influencing VAS.

   Results Top

SPO2, PR and CS, VAS were analysed for the patient at both the appointments (A1 and A2) groups; A1: Restoration was done under N2O-O2, A2: Restoration was done under 100% oxygen.

The mean value for SPO2 at A1 was 97.1 and at A2 was 98.6; with difference being non-significant (P = 0.72). Mean value for PR at A1 was 95.5 and at A2 was 100.2; with difference being non-significant (P = 0.902), Mean value for CS at A1 was 18.4 and at A2 was 13.2; with difference being significant (P = 13.2), Mean value for VAS at A1 was 3.8 and at A2 was 3.4; with difference being non-significant (P = 0.432).

   Discussion Top

Dental phobia is a commonly encountered problem in pediatric dentistry. Achieving behaviour modification and instilling a positive behaviour at subsequent appointments is the mainstay of pediatric dental treatment.[7]

Various pharmacological modalities like oral, IV, inhalation sedation and non-pharmacological behaviour management techniques such as voice control, home, classical conditioning, and aversive conditioning have been tried over the years. N2O as a behavioural modification intervention in children has attained an excellent safety record and is, therefore, used widely.[8]

This study was undertaken to evaluate the effect of N2O as behaviour modification technique and its capacity to carry out effective and efficient dental care at the subsequent appointment even without administrating N2O; using it as a placebo, that is, giving 100% O2 through the nasal hood.

The principle utilized here is “Rejuvenation of Ivon Pavlov's dream to induce classical conditioning in paediatric patients”. In this study, we replaced the Pavlov's experiment's subjects with sedation room equipment's that is dog before classical conditioning was replaced by pediatric patient, Ivan Pavlov was replaced by observer who was same in every case, food was replaced by N2O, Bell was replaced by nasal hood, salivation in the dog on thinking of food was replaced by cooperative patient under 100% of oxygen.

The patient's comfort level was assessed with the help of CS which was first used by Ambuel et al. in 1992 for evaluating distress in mechanically ventilated patients in pediatric ICUs, although it was predominantly employed to assess level of sedation or distress.[9],[10] The COMFORT comprises seven items with five response categories each consisting of distinct behavioural descriptions. Seven behavioural items are Alertness, Calmness, Muscle tone, Movement, Facial tension, respiratory response, and crying. Respiratory response was not included in our study as it is only recorded when child is mechanically ventilated. The value of CS was found to be significant in comparison of A1 and A2. A possible explanation of this significant finding is the behaviour modification in first visit as that patient attains faith on dentist as well as believes that procedure would not result in pain thereby decreasing fear and anxiety on the subsequent visits thus all the parameters of CS might get reduced.

Another parameter evaluated with this scale is VAS; The VAS is considered to be the best method for recording intensity of pain.[11] VAS scores improved for all the patients in the second appointment, though the results were statically non-significant.

On evaluating the physiological parameters, that is, PR and SPO2; it was observed that the PR values decreased slightly and SPO2 levels improved. Though the results were statistically non-significant [Table 1].
Table 1: Intercomparison of mean scores of SPO2, PR, CS, VAS amongst the two groups

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The results of this study hold special significance in those cases in where; Patient is scheduled for multiple appointments and the parents are quite apprehensive for repeated exposure of N2O as treatment modality. It may also be of advantage in those cases where in the subsequent appointments patient is suffering from nasal blockage or cough and cold. Further administration of oxygen is not technique sensitive; it can be operated by untrained operator. Hence N2O may help in instilling positive dental attitude, which if achieved in the first appointment may create a positive dental attitude for subsequent appointment as well.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (ITSCDSR/IIEC/RP/2018/025).

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Roberts JF, Curzon ME, Koch G, Martens LC. Behaviour management techniques in paediatric dentistry. Eur Arch Paediatr Dent 2010;11:166-74.  Back to cited text no. 1
Kühnisch J, Daubländer M, Klingberg G, Dougall A, Spyridonos Loizides M, Stratigaki E, et al. Best clinical practice guidance for local analgesia in paediatric dentistry: An EAPD policy document. Eur Arch Paediatr Dent 2017;18:313-21.  Back to cited text no. 2
Clinical Affairs Committee-Behavior Management Subcommittee, American Academy of Pediatric Dentistry. Guideline on behavior guidance for the pediatric dental patient. Pediatr Dent 2015;37:57-70.  Back to cited text no. 3
McWhorter AG, Townsend JA, American Academy of Pediatric Dentistry Symposium. Behavior symposium workshop A report-Current guidelines/revision. Pediatr Dent 2014;36:152-3.  Back to cited text no. 4
Cianetti S, Paglia L, Gatto R, Montedori A, Lupatelli E. Evidence of pharmacological and non-pharmacological interventions for the management of dental fear in paediatric dentistry: A systematic review protocol. BMJ Open 2017;7:e016043.  Back to cited text no. 5
Finniss DG, Kaptchuk TJ, Miller F, Benedetti F. Biological, clinical, and ethical advances of placebo effects. Lancet 2010;375:686-95.  Back to cited text no. 6
Finucane D. Rationale for restoration of carious primary teeth: A review. Eur Arch Paediatr Dent 2012;13:281-92.  Back to cited text no. 7
V KP, Gaur D, Ganesh M, Ch SK. Conscious sedation in pediatric dentistry: A review. Int J Contemp Med Res 2016;3:1577-80.  Back to cited text no. 8
Ambuel B, Hamlett KW, Marx CM, Blumer JL. Assessing distress in pediatric intensive care environments: The COMFORT scale. J Pediatr Psychol 1992;17:95-109.  Back to cited text no. 9
Vandijk M, de Boer JB, Koot HM, Tibboel D, Passchier J, Duivenvoorden HJ. The reliability and validity of the COMFORT scale as a postoperative pain instrument in 0 to 3-year-old infants. Pain 2000;84:367-77.  Back to cited text no. 10
Scott J, Huskisson EC. Graphic representation of pain. Pain 1976;2:175-84.  Back to cited text no. 11

Correspondence Address:
Dr. Vinita Goyel
Department of Pediatric and Preventive Dentistry, ITS-CDSR, Muradnagar, Ghaziabad, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijdr.ijdr_146_21

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