Soft Tissue Anaesthesia Clinical Trial
Official title:
Reversing the Effects of 2% Lidocaine: A Randomized Controlled Trial
Dental procedures often require the use of local anesthesia. The effects of the anesthesia
usually linger for some time after the dental procedure is completed which can lead to
discomfort and occasionally injury from lip/tongue biting. Clinical trials have shown
phentolamine mesylate (OraVerse) to be effective at reducing the amount of time to reversal
of local anesthesia compared to sham injections. However, no trials have been conducted
comparing phentolamine mesylate to a true control injection. Such trials are needed in order
to definitively show that it is the phentolamine mesylate itself that is causing the
reduction in anesthesia rather than a dilution effect.
The objective of the proposed research is to conduct a pilot-scale randomized clinical trial
evaluating the difference in time required to the return of normal soft-tissue sensation and
function in participants who had received an inferior alveolar nerve block (using 2%
Lidocaine 1:100,000 epinephrine), followed by an injection with either 1) OraVerse
(phentolamine mesylate) or 2) sterile physiological water (control).
The study population will comprise dentistry and dental hygiene students of the second year
classes at Dalhousie University, Halifax, NS, Canada. This study population has been chosen
because these students usually practice dental anesthesia on each other as a part of a
course on local anesthesia.
This proposed pilot scale study will be a double-blind controlled trial using parallel
groups. As part of their usual anaesthesia course, the dental and dental hygiene students
will be practicing their inferior alveolar nerve injections on one another using 2%
Lidocaine 1:100,000 epinephrine. Students who decide to participate in the study will be
randomly assigned to one of two groups: Group 1 will receive an injection of OraVerse
(treatment group), while Group 2 will receive an injection of sterile physiological water
(control group). The time required to the return of soft-tissue sensation and function will
be assessed using a questionnaire.
The research will be conducted at the Dalhousie University Dental Clinic. As part of their
anaesthesia clinical course, students enrolled in the second year of the dentistry and
dental hygiene programs practice different anesthesia techniques on each other during a
planned hands-on training activity. The research study will take place during the same day.
Participants who meet the eligibility criteria and consent to participate will be randomly
assigned to one of two groups. Following anesthesia obtained as a part of their hands-on
training session, subjects allocated to Group 1 will receive 1ml of phentolamine mesylate
following anesthesia, while subjects allocated to Group 2 will receive 1ml of sterile
physiological water.
Phase 1, Both Groups:
1. Subjects will be trained to use the Assessment of Anesthesia questionnaire
2. Following training, subjects will perform baseline assessments of their lip and tongue
numbness (should be normal).
3. Prior to anaesthesia is given, vital signs will be recorded. Blood pressure,
respiratory rate and pulse will all be recorded.
4. Topical anesthetic, 20% benzocaine, will be applied to the injection site for 3
minutes. Subjects will be given a standard inferior alveolar nerve block injection,
with aspiration before injection, using 1ml of 2% lidocaine with 1:100,000 epinephrine
from the student they are teamed with. This step is not part of the study; it is done
as part of their clinical anesthesia course.
5. Soft tissue anaesthesia will be self-assessed, by using finger tapping and palpation,
to ensure profound anesthesia. The second phase (OraVerse or water) will not take place
before profound anesthesia has been achieved. The anesthetic outcome will be considered
a failure if the participant does not report anesthesia of the lower lip within 10
minutes.
6. If profound anesthesia is achieved within 10 minutes, subjects will proceed to phase 2.
If profound anesthesia is not achieved within 10 minutes subjects will be withdrawn
from the study. Subjects who are withdrawn from the study will continue with their
standard training protocol which is to receive a re-injection of anesthetic. A
withdrawal form will be used by Dr. Flood to record the occurrence of anesthesia
failures. This form will also record reasons for withdrawals, should any occur for
different reasons.
Phase 2 Group 1: Phentolamine Mesylate After anesthesia is confirmed, subjects in Group 1
will receive an injection of 1ml of a solution containing 0.24mg of phentolamine mesylate in
the same site previously injected with anaesthetic solution. Dr. Brittany Flood will give
the injection to ensure consistency.
Group 2: Water After anesthesia is confirmed, subjects in Group 2 will receive an injection
of 1ml of sterile physiological water in the same site previously injected with anesthetic
solution. Dr. Brittany Flood will give the injection to ensure consistency.
Phase 3 Vital signs will be taken immediately after injection, by their student partner, and
all students will be monitored for 30 minutes. During the monitoring period, the
participants will self-assess their anesthesia, using the Assessment Of Anesthesia
questionnaire. This self-assessment will be done every ten minutes until soft-tissues revert
to their normal state. After the 30 minute monitoring period participants will be free to
leave the clinic, taking the questionnaire with them but will continue to check for
anesthesia every 10 minutes until tissue sensation and function return to normal. Students
will be instructed to return the forms to the office of the Research Development Officer.
The Case Report Forms will include the following:
- Assessment Of Anesthesia questionnaire: self-assessment of state of soft-tissue
anesthesia
- Subject Eligibility Checklist: inclusion/exclusion criteria
- Consent form
- Participant Identification allocation Log (centrally kept): Participant study ID and
chart number
- Treatment Group Allocation Log (centrally kept): Participant study ID and treatment
group ('A' or 'B')
- Withdrawal information
- Adverse Event form
Recruitment and reversal injections will be done by Dr. Brittany Flood, who is a licensed
dentist currently enrolled as a student in the Masters of Periodontics program at Dalhousie
University Faculty of Dentistry. Dr. Pierre-Luc Michaud who is a dentist and full-time
assistant professor at Dalhousie Dentistry will supervise the project and perform data
analysis. He will not be involved in recruitment and will not be present during the clinical
phase of the study. Dr. Brittany Flood is not in a position of authority with the dental or
dental hygiene students and will therefore be the only research member working directly with
the participants. She will be the only research team member aware of who has volunteered to
be in the study.
Two weeks before the anesthesia session, the potential participants will be given a thirty
minute presentation, followed by a question and answer session. On the evening of the
anesthesia course session, the initial numbness assessment (2 minutes) and reversal
injection (5 minutes) will be the only clinical time required from participants in the
study, as the other manipulations (vital signs monitoring and 30 minutes post-injection
waiting-time period before leaving) are a standard part of their course. Following the
clinical portion, participants will be free to leave the clinic but will continue to check
for anesthesia every 10 minutes and then fill out a short questionnaire when sensation and
function return to normal (to record duration of soft-tissue anesthesia). The duration of
anesthesia could take between 1 and 2.5 hours, depending in which group the participant is.
This study is a randomized double-blind study. The Research Development Officer of the
Faculty of Dentistry will be responsible for the randomization procedure. A computerized
random number generator will be used to generate six randomly permuted blocks, with a block
size of six. Within each block, an equal number of subjects will be allocated to the two
treatment groups ('A' or 'B'). These will refer to either OraVerse group or Control group,
but the Research Development Officer will withhold the information until the statistical
analyses are completed. She will however give a copy to the supervisor of the anesthesia
training session (who is not involved in the study) so that the information on what was
injected could be quickly accessed during the hands-on if required and to appropriately fill
participants' clinical chart. The allocations will be placed in sequentially numbered (01
through 36), opaque, sealed envelopes (referring to participants' ID) to be opened at the
time of participant's reversal injection. The treatment group (A or B) randomly assigned for
each participant will be recorded in the Treatment Group Allocation Log. The syringes will
be marked as 'A' or 'B'; the person injecting (Dr. Brittany Flood) will not know which
contains OraVerse (PM) and which contains water. As previously discussed, the anesthetic
course supervisor will however have the information as a safety measure and to appropriate
fill the patients' chart. To ensure continuous blinding of allocation, the randomization
code will be kept secret by the Research Development Officer until after data analysis. Only
the participant study ID will be used to label the subject's case report forms. Only the
Participant Identification allocation Log could associate the participant ID with the
patients' chart number, but this file will be kept centrally during the study time.
;
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator), Primary Purpose: Treatment