A Study of the Use of Microneedle Patches to Deliver Topical Lidocaine in the Oral Cavity

To look at the effect on patient perceived pain resulting from infiltration injection with local anaesthetic in a dental syringe with prior application of topical anaesthetic to the oral mucosa on a microneedle patch compared to a patch with no microneedles. To look at the safety of the patches when applied to the oral mucosa.

This is a randomised, 2 treatment, double blind design, with respect to the clinical assessor and subject, split mouth, crossover design with a negative control (patch with no microneedles).

Potential participants will be invited to attend a screening visit. At this visit participants will be asked to read and sign a Participant Information Sheet and Consent Form prior to any study procedures being performed. They will be given ample time to decide if they wish to participate in the study.

A dentally qualified clinician will record the participant's demographics, medical history, current/concomitant medications, perform an oral soft tissue examination and ensure the participant fulfils the inclusion and exclusion criteria for the study. Two areas of the mouth will be identified for assessment during the study. The areas of the mouth will be identified as S1 or S2. Site S1 will be left or right palatal mucosa adjacent to the premolar area and S2 will be left or right upper buccal mucosa adjacent to the upper lateral incisor area.

Participants who successfully fulfil all the necessary entrance criteria will be provided with training by study staff on how to use a VAS record sheet and randomised on to the study to receive treatment combination A or B at in a random order according to a predetermined randomisation schedule supplied by the study statistician. The screening visit and first treatment visit will occur at the same visit. The treatment possibilities are outlined below:

Treatment A The application of a 5% topical lidocaine gel to one of the identified areas within the participants mouth using a microneedle patch. The microneedle patch will be applied to the oral mucosa of the identified site for 3 minutes, followed by infiltration with local anaesthetic to one of the identified areas within the participants mouth.

Treatment B The application of a 5% topical lidocaine gel to one of the identified sites within the participants mouth using a patch with no microneedles. The patch with no microneedles will be applied to the oral mucosa of the identified site for 3 minutes, followed by infiltration with local anaesthetic to one of the identified areas within the participants mouth.

The chosen sites will be: S1; left and right palatal mucosa adjacent to the premolar area or S2; left and right upper buccal mucosa adjacent to the upper lateral incisor area. Each participant at the first visit will have either S1 or S2 sites allocated for treatment. For example, Treatment A will be allocated to S1 left side and Treatment B to S1 right side or vice versa. At the second visit, 2 weeks (+/- 3 days) after the first visit, Treatment B will be allocated to S2 left side and Treatment A to S2 right side. Both sides of the mouth for S1 or S2 will be treated at the same. After each treatment participants will be asked to make pain assessments relating to needle insertion into the oral mucosa and the giving of the local infiltration anaesthetic.

It is envisaged that a sufficient number of potential participants will be screened in order to randomise 16 onto the study.

Assessment methods: Pain assessments will be performed after application of the topical anaesthetic for 3 minutes. Each test will be performed sequentially i.e. 3 separate needle insertions, with pain assessments recorded by the participant using a Visual Analogue Scale (VAS) and a verbal pain grading after each test. The level of pain at S1 or S2 will be assessed as follows:

Test I. A short dental needle, mounted on a dental syringe containing a cartridge of 2% lidocaine hydrochloride and 1:80,000 adrenaline, will be used to penetrate the oral mucosa at the treated site and the patient asked to score the pain using a VAS rating scale and by verbal grading of zero, mild, moderate or severe.

Test 2. The same needle will be inserted through the oral mucosa and down to contact bone. Pain will be assessed as in Test 1.

Test 3. The same needle will be again inserted through the oral mucosa and the cartridge of local anaesthetic will be injected into the site. Pain will be again assessed as in Test I.

Following enrolment on to the study, participants will be given written and verbal instructions on the VAS and how to complete it.

Eligibility Criteria:
Inclusion Criteria:

1. be aged 18 years and over, of either gender and in good health;
2. be willing and physically able to carry out all study procedures;
3. be willing and able to give Informed Consent and provide details of any medical history;
4. be available for all of the study dates
5. have a good standard of oral hygiene and gingival health
6. must have 1 premolar or canine in each quadrant that has no/minimal restorations

Exclusion Criteria:

1. presence of soft tissue oral pathology;
2. presence of advanced periodontal disease;
3. Individuals with any serious health conditions, that would preclude participation, in the professional judgement of the Study Dentist;
4. individuals with known allergies or sensitivities to local anaesthetics
5. have participated in another clinical trial in the last 30 days
6. in the opinion of the investigator unable to comply fully with the trial requirements.
7. the subject is an employee of the Sponsor or the site conducting the study