Clinical Outcomes of Buffered vs. Non-Buffered Lidocaine

Anecdotal reports suggest buffering lidocaine with epinephrine just before intraoral injection reduces time of onset, results in a deeper anesthetic effect, without the "sting" with injection from a low pH. Additional data are needed to establish clinical important outcomes such as the peak blood level of lidocaine as compared to the non-buffered drug combination.

Clinical pilot studies are proposed as the start of a series of investigations to support or modify the use of the buffered anesthetic for intraoral procedures.

Specific Aims:

Compare blood levels at 30min post injection mandibular block with buffered and non- buffered 2% lidocaine with 1/100k epinephrine. Assess outcomes (pain levels during and post-injection, and onset of anesthesia symptoms) after buffered and non-buffered oral administration of 2% lidocaine with 1/100k epinephrine. Assess possible topical anesthetic properties of buffered and non-buffered oral administration of 2% lidocaine with 1/100k epinephrine

Hypotheses:

No difference in peak blood levels exist between buffered and non-buffered intraoral injection of 2% lidocaine with 1/100k epinephrine.

Injection of buffered local anesthetic will produce less discomfort for the subject as compared to the drug with a low pH.

Buffered local anesthetic will not produce a topical anesthetic effect

Study Time Frame: 6 months Month One IRB approvals. Recruit volunteers as subjects. Prepare case-books. Months Two-Three Clinical Study Months Four-Five Analyze Lab, QOL data Month Six Prepare Abstracts, Papers

Methods: Blinded, Randomized Clinical Design Recruit subjects with IRB approved consent at UNC Target enrollment 24 subjects Subjects will serve as their own controls in a cross-over AB/BA study design which is uniform within sequences, uniform within periods, and balanced Sample size justification: Primary interest is estimation of effect size from pilot study. 24 subjects should be sufficient to provide data to assess whether a larger study is warranted and provide estimates for sample size calculation for larger studies. Vital signs recorded: 10 min before, during at 30min intervals and after post-anesthetic clinical signs disappear: targeted lower lip no longer numb. Randomized subjects to be injected alternatively with 4cc of buffered and 4cc non-buffered oral administration of 2% lidocaine with 1/100k epinephrine.

SAS will be used to create randomization schedules:

The randomization will be performed first to type of drug given with a balanced randomization (half subjects buffered; half to non-buffered) An OMS resident, Dr Phero, will administer the drugs in the OMS clinic.

In week One each subject would receive anesthetic to block the inferior alveolar and lingual N; Halstead or Gow-Gates techniques. No Buccal N. block. At least a week later injections would involve the alternate local anesthetic combination.

Venous blood samples would be drawn from the antecubital fossa 30min post oral injection and assayed for blood lidocaine levels Timed Assessment: pre, during injection, and post-anesthetic for Clinical Onset of Anesthesia Signs: subject reported molar area numbness and numb lower lip on ipsilateral injected side. Assessment for pain level on injection; modified Likert-type scale

In addition at each clinic session an assessment of a topical anesthetic effect on contralateral lower lip with 5 drops of the injected drug placed on the clinically dry lower lip mucosa, Outcome yes/no.

Data Collection: UNC OMS clinic Venous blood samples (10cc) will be drawn from the antecubital fossa 30min post oral injection. Timed assessment pre, during injection, and post-anesthetic clinical Signs: molar area anesthesia, incisor area anesthesia, and numb lower lip for topical

Data Collection/Analysis:

Data will be managed by study staff. Data collection forms and questionnaires for clinical data will be developed to use Teleform for direct scanning input into an ACCESS database. Similar forms have been used in previous studies. All databases are stored on a password protected School of Dentistry server with specific group assignment. SAS will be used for database management and statistical analysis. Descriptive statistics are used to verify correct entry through range and logical checks.

Eligibility Criteria:
Inclusion Criteria:

* Age 18-30 years
* ASA I
* Willingness to complete QOL instrument
* Willingness to participate in two sessions

Exclusion Criteria:

* Allergy to lidocaine class of anesthetic drugs
* Local anesthetic drug use in past week
* Current symptoms teeth or oral mucosa