Comparison of Bite Force After Administration of Midazolam and Dexmedetomidine for Conscious Sedation in Minor Oral Surgery.

AIM: The aim of this study was to compare the bite force and sedation score in moderate/conscious sedation for minor oral surgical procedure.
MATERIALS AND METHODS: A sample size of 30 was selected in each group (group M [midazolam] and group D [dexmedetomidine]).
RESULTS: Dexmedetomidine group had a statistically significant sedation score than midazolam. A statistically significant increase in the bite force was observed in both midazolam and dexmedetomidine groups, but there was no significant difference between the two groups.
CONCLUSION: Dexmedetomidine and midazolam significantly increased the bite force because of the loss of proprioceptive function of periodontal ligament, but there was no significant difference between the drugs regarding bite force.

INTRODUCTION

Moderate sedation (conscious sedation) is a drug- induced depression of consciousness during which a patient responds purposefully to verbal commands, either alone or accompanied by physical stimulation. No interventions are required to maintain a patent airway and spontaneous ventilation is adequate.

Midazolam has been the commonly used benzodiazepine in conscious sedation. The beneficial pharmacological properties of midazolam include rapid onset, short duration of action, and anxiolytic and anterograde amnestic effects; hence, it shows promising results in office settings for minor oral surgical procedures.[1]

Dexmedetomidine is a recently introduced drug for conscious sedation. Dexmedetomidine was approved by the U.S. Food and Drug Administration (FDA) at the end of 1999 for use in humans as a short-term medication (<24 hours) for analgesia and sedation.[2] Dexmedetomidine is a highly selective α-2 adrenoceptor agonist. Sympathetic activity is inhibited when these receptors are activated in the central nervous system. Because of its analgesic property, shorter recovery profile. and less cognitive impairment and respiratory depression, dexmedetomidine may be a better choice of drug than midazolam for sedation in minor oral surgical procedures.[3]

The dentist should be alert while using conscious sedation because he/she might get injured accidently by the patient because of excessive masticatory force and reduced level of consciousness. There has been no study addressing the effects of dexmedetomidine on masticatory muscle power.

MATERIALS AND METHODS

A sample size of 30 in each of the two study groups (group M [midazolam], group D [dexmedetomidine]) were selected. The selection criteria were determined according to a confidence interval of 95% with level of significance of 5% using the mean value of previous investigations. This was a double-blinded study designed to neglect any operator bias, and the protocol was approved by the ethical committee of Sri Ramachandra institute of higher education and research (Deemed to be University)

Inclusion criteria: (1) age group in between 18 and 40 years, and (2) American society of anesthesiologists I, II patients.

Exclusion criteria: (1) patients aged below 18 years and above 40 years; (2) patients with the history of neurologic, cardiac, pulmonary, hepatic or renal disease, mental disorders or drug addiction, bleeding disorders, and those on anticoagulants and antiplatelet drugs; (3) patients with missing permanent first molars; and (4) patients allergic to midazolam or dexmedetomidine.

First the preanesthetic fitness of the patients was assessed. Then the patients were briefed to fast for 6 hours before the minor oral surgical procedure and advised to be accompanied by a person during street fit discharge. Before the commencement of the minor oral surgical procedure, the patients were seated in a semi-supine position and were advised to close their eyes for 5 minutes for relaxing. Using nasal prongs, supplemental oxygen was administered. The patients were then monitored with a pulse oximeter, and baseline heart rate, electrocardiogram, arterial oxygen saturation, blood pressure, and respiratory rate were recorded.

A loading dose of midazolam 0.05 mg/kg or dexmedetomidine 1 μg/kg/h was administered through a microinfusion syringe pump for 10 minutes through an intravenous cannula. The additional infusion of 0.5 μg/h of dexmedetomidine along with 250 mL of saline serves as a maintenance dose till the termination of the procedure. The anesthetist prepared, administered, and recorded the drug doses during this study and was blinded to neglect operator bias. Ramsay Sedation Score was recorded by the operator after the administration and before the commencement of the minor oral surgical procedure.

The Ramsay Sedation Score details are as follows—Score 1: patient is anxious and agitated, or restless, or both; Score 2: patient is cooperative, oriented, and tranquil; Score 3: patient responds to commands only; Score 4: patient exhibits a brisk response to a light glabellar tap or loud auditory stimulus; Score 5: patient exhibits a sluggish response to a light glabellar tap or loud auditory stimulus; and Score 6: patient does not respond to a light glabellar tap or loud auditory stimulus.

The procedures were performed under local anesthesia using Lignocaine HCl with 1:200,000 epinephrine. Before inducing sedation, the bite force was recorded and was measured at an interval of 5, 10, 20, and 30 minutes during the surgical procedure. The bite force was recorded using a custom-made bite force recorder designed for this study [Figure 1]. It had a Kistler quartz force transducer, which acts as the sensory unit of the device. The housing of the device was covered on both sides using 2-mm thick rubber plates mounted on double-sided adhesive tapes to curtail metallic impact on the teeth. The whole system was covered with rubber plates and a disposable latex finger cot. Bite force was recorded unilaterally as the chewing is largely unilateral. The maximal bite force was recorded. The results were revealed on a liquid crystal display [Figure 2].[4] SPSS (Statistical Program for Social Science, version 16) was used for statistical analysis.

Figure 1

Bite force measuring device

Figure 2

Measuring bite force and liquid crystal display

RESULTS

For bite force intragroup comparisons and repeated measures analysis of variance were conducted. The Student’s t test was used for intergroup comparisons for paired samples. The statistical normality was confirmed before parametric analyses. P value of ≤0.05 was considered statistically significant.

Dexmedetomidine group had a statistically significant sedation score than midazolam, which was proved by the P value less than 0.05 after 10 minute [Table 1]. Bite force increased after administration of either drugs but there was no statistically significant difference between the two drugs [Table 2]. A statistically significant increase in the bite force was obtained at all the given time intervals in the dexmedetomidine and midazolam groups [Table 3].

Table 1

Mean sedation score

Drug	Preoperative	5th minute	10th minute	20th minute	30th minute
Dexmedetomidine	1	1.90	2.4	2.9	2.86
Midazolam	1	1.96	1.9	2.4	2.56
P value*	1.00	0.67	0.011	0.00	0.025

*P value between two groups

Table 2

Mean bite force in pounds

Drug	Preoperative	5th minute	10th minute	20th minute	30th minute
Dexmedetomidine	28.21	31.60	32.37	32.48	33.8
Midazolam	28.54	33.44	33.04	33.51	31.99
P value*	0.86	0.51	0.80	0.68	0.45

*P value between two groups

Table 3

Paired sample test for bite force (pounds)

Dexmedetomidine group			Midazolam group
Time period	Bite force increased	P value*	Time period	Bite force increased	P value*
5th minute	3.39	0.01	5th minute	4.90	0.007
10th minute	4.16	0.00	10th minute	4.50	0.012
20th minute	4.27	0.00	20th minute	4.97	0.04
30th minute	5.64	0.00	30th minute	3.45	0.65

*P value between specific time period

DISCUSSION

Muglali and Komerik[5] stated that anxiety and pain are the most common complaints of patients undergoing minor oral surgical procedures.

In this study we have compared the efficacy between midazolam and dexmedetomidine in relation to bite force and sedation score. Previous studies have shown that when patients were sedated with midazolam, significantly higher number of patients showed pain reactions and an increase in bite force.[3] Midazolam increases the γ-aminobutyric acid A receptor-mediated functions in the central nervous system and acts on the spinal pathway to decrease the muscle power.[1]

Dexmedetomidine is a potent, highly selective α-2 adrenoceptor agonist. Activation of these receptors in the central nervous system leads to inhibition of sympathetic activity, which causes reduction in blood pressure, heart rate, decreased arousal, sedation, anxiolysis, and an analgesic effect.[6] Dexmedetomidine may prove to be a better sedative drug for oral surgery than midazolam because of its analgesic property, shorter recovery profile, less cognitive impairment, and less respiratory depression.[3]

There is only one study on the effect of midazolam on bite force measurement,[7] but there has been no report on the effect of dexmedetomidine on muscle power, including the muscles of mastication. Therefore, in this study, the effects and comparison of midazolam and dexmedetomidine on bite force were investigated.

Huang et al.[7] reported that the bite force was increased during midazolam sedation. Several mechanisms could explain the reason behind this. First, relaxation during sedation may increase masticatory muscle performance. Second, midazolam may have some inhibitory effects on the jaw reflex system such as the jaw-opening reflex. Third, subjects under sedation may not perceive the limit of masticatory muscle contraction, which they can sense instinctively during an alert state. Fourth, peripheral-type benzodiazepine receptors may be involved in the increase of bite force.[7]

The results obtained in our study show that the bite force of both the groups significantly increased after administration of these intravenous sedation drugs. The comparative analysis showed that there is no clinical or statistical difference in the amount of bite force that increased between the two drugs [Table 2]. In our study, multivariant analysis showed that, by the 30th minute, the amount of increased bite force in midazolam was not statistically significant [Table 3]. But in the dexmedetomidine group, continuous increase in bite force was noted between every time interval [Table 3]

CONCLUSION

The bite force was increased after administration of either drugs but there was no significant difference between the dexmedetomidine and midazolam groups. A statistically significant increase in the bite force was obtained at all the given time intervals in the dexmedetomidine group and in midazolam group from 5until 20 minute, after which there was an increase in bite force but it was not statistically significant. Patients were having better sedation in the dexmedetomidine group compared to Midazolam.

In this study, it has been found that bite force increased during the administration of midazolam and dexmedetomidine as conscious sedation. The increase in bite force might be because of the suppression of proprioceptive reflex during conscious sedation.

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

Nil.

Conflicts of interest

There are no conflicts of interest.