Scientific Article

Reducing children’s injection : lidocaine patches versus topical gel

Kathryn A. Kreider, DMD Robin G. Stratmann, DDS Michael Milano, DMD Francesca G. Agostini, DDS, MS Mark Munsell

Dr. Kreider is a private practitioner, Dixon, IL ; Dr. Stratmann, Dr. Milano, and Dr. Agostini are all assistant professors in Pediatric Dentistry, at the University of Texas-Houston Health Science Center, Houston, TX; Statistical analysis was provided by Mr. Mark Munsell, Anderson Hospital, Houston, TX. Correspond with Dr. Milano at [email protected] Abstract Purpose: The purpose of this study was to compare the effec- four studies6-9 found no difference in the effectiveness of topi- tiveness of lidocaine patches and topical gel in reducing cal anesthetic and a . injection pain in children. Two similarly designed studies3,8 compared effectiveness of Methods: Thirty-two children received bilateral greater pa- vs. placebo during injection of 0.3 ml of 2% latine injections of 0.2cc of 2% lidocaine with 1:100,000 lidocaine near the greater palatine canal. Bilateral injections at the same visit. Injections followed a 15 minute were completed at the same appointment after application of application of DentiPatchTM (20% lidocaine) or a 1 minute ap- either topical anesthetic or placebo. Yaacob3 reported that plication of topical anesthetic gel (Topex, 20% benzocaine). Each topical anesthetic (5% lidocaine) was superior to the placebo child completed a Faces Pain Scale and Visual Analog Scale after while Keller8 found no difference between topical each injection and was asked which injection hurt more. Injec- (18 or 20% benzocaine) and placebo in reducing injection pain. tions were videotaped and two independent evaluators, using the Keller alternated injection order and which quadrant received Sounds, Eyes, and Motor Scale, rated observed pain-related be- the topical anesthetic while Yaacob did not. Martin et al2 found havior. Inter-rater reliability was established at 96%. injection order influenced patient perception of pain with the Results: A significant difference was shown in observed pain- second injection being perceived as more painful than the first. sounds favoring use of the DentiPatch (P<.003, Wilcoxon Sign However, in pediatric dentistry the use of a topical anesthetic Rank Test). Using Wilcoxon Sign Rank Test and paired t-tests, agent is considered commonplace prior to the administration no significant differences were shown in either reported pain or of local anesthesia. observed pain-motor. The Noven DentiPatchTM is a non-invasive pain control Conclusions: A statistically significant decrease in observed patch which provides site-specific delivery of anesthesia.11,12 verbal indicators of injection pain was found when the DentiPatch The current FDA-approved indication for the DentiPatchTM was used 20%: compared to a 1 minute application of topical an- system is the production of mild topical anesthesia of the mu- esthetic gel. However, no significant difference was found between cous membranes of the mouth prior to superficial dental the two study groups in either reported pain or observed pain-motor procedures. The manufacturer notes that the patch may re- responses. (Pediatr Dent 23:19-23, 2001) duce the pain of injections into the gingiva. The DentiPatch contains 46.1mg of lidocaine (20% concentration) or 23.1 mg educing injection pain in children may help to provide lidocaine (10% concentration) which diffuses into the mucosa. overall comfort and well being during the entire dental Hersch et al13 found systemic absorption of lidocaine for the Rexperience. Pediatric dentists are constantly searching 20% lidocaine patch was approximately 10% of that which for tools which may provide a more comfortable dental proce- results from an infiltration injection of 36 mg lidocaine with dure. The challenge is to find an effective method that can be .018 mg epinephrine. This must be considered in the total utilized in the pediatric population. A recent study by Wilson calculation of dosage.14,15 The patch may be et al1 demonstrated the benefits of electronic left in place up to 15 minutes,11 at which time maximal anes- in reducing discomfort as judged by both behavioral and physi- thesia is produced.13 Both 10% and 20% lidocaine patches have ological parameters in young sedated dental patients. Topical been found superior to placebo patches in reducing reported anesthetics function by blocking signal transmission in the ter- pain after insertion of a 25 gauge needle apical to the minal fibers of sensory nerves. Their effects are limited to the mucogingival junction in the premolar area in adults.13,16 control of painful stimuli occurring in or just beneath the mu- The benefit of the new lidocaine patch delivery system has cosa. The literature reports mixed results regarding the efficacy yet to be evaluated in children. The purpose of this study was of topical anesthetics in reducing injection pain. Of seven pub- to compare the effectiveness of intraoral lidocaine patches and lished placebo controlled trials reviewed by Martin, et al,2 three topical anesthetic gel in reducing injection pain in children as studies3-5 found topical anesthetic superior to a placebo, while measured by a reduction of pain, fear, and anxiety experienced by children during the administration of local anesthesia. Received April 7, 2000 Revision Accepted December 22, 2000

Pediatric Dentistry – 23:1, 2001 American Academy of Pediatric Dentistry 19 Table 1. Sounds, Eyes, Motor Scale17

Observations 1 comfort 2 mild discomfort 3 moderately painful 4 painful Sounds no sounds indicating pain non-specific sounds; specific verbal complaints verbal complaint indicates possible pain indications “OW” raises voice intense pain, e.g. scream, sobbing. Eyes no eye signs of discomfort eyes wide, show of watery eyes, eyes flinching crying, tears running down face concern, no tears Motor hands relaxed no apparent hands show some distress random movement of arms movement of hands to make body tenseness or tension; grasps chair due or body without aggressive aggressive contact, e.g. punching, to discomfort, intention of physical pulling head away muscular tension contact, grimace, twitch

Methods of 0.2cc 2% lidocaine with 1:100,000 epinephrine completed. Thirty-two patients between 6 and 15 years of age participated The highest heart rate in the immediate post-injection period in this study. Criteria for inclusion were cooperative behav- was recorded. When baseline heart rate was attained, the nasal ior, ability to complete the Faces Pain Scale and Visual Analog hood was removed and the patient completed the Faces Pain Scale, ASA Class I, no contraindications to lidocaine or other Scale and Visual Analog Scale for that injection. The patient local anesthetics, and no history of contact dermatitis. The was returned to the supine position, the nasal hood placed, child must have exhibited bilateral maxillary posterior caries 100% oxygen administered for 5 minutes, and baseline heart in need of operative and/or surgical treatment. The parent or rate recorded. Approximately 0.1 ml of topical anesthetic guardian gave written informed consent for the institutionally (Topex, 20% benzocaine) was applied for 1 minute to the area approved study. of the greater palatine canal of the contra-lateral quadrant and Materials used were the DentiPatchTM (20%) (Noven Phar- the greater palatine injection of 0.2cc of 2% lidocaine with maceuticals, Miami, FL), 20% benzocaine topical anesthetic 1:100,000 epinephrine completed. A new 27-gauge needle was gel (TopexTM, Sultan), 2% lidocaine with 1:100,000 epineph- used for each injection. The highest heart rate post-injection rine (Schein, New York), and 27-gauge short dental needles was recorded. When heart rate returned to baseline, the patient (Monoject, Sherwood Medical, St. Louis, MO). Physiologic completed the Faces Pain Scale and Visual Analog Scale for that monitoring equipment used was the Criticare pulse oximeter injection. The child was then asked which injection hurt more. Scholar II (Criticare, Waukesha, WI). A Porter All injections were completed by the principal investigator delivery system was used. A wall-mounted video camera re- who attempted consistency in rate of injection and verbal in- corded behavior during injections. structions to the patient. This was established by utilizing the After a review of the current health status with the parent/ lidocaine patch on several patients prior to the initiation of the guardian, the child was seated in a private operatory and the study. In each instance, the needle was inserted into the tissue pulse oximeter attached to the patient. Injection order and with the bevel facing the periosteum. The nasal hood was placed determination of which quadrant received the lidocaine patch and 100% oxygen was administered to serve as a placebo, a or topical anesthetic gel was randomly determined. The distraction technique, and a visual block of the . Once lidocaine patch was applied to the area of the right or left greater the greater palatine injections were given, the study portion of palatine canal for 15 minutes. The nasal hood was placed and the appointment was complete. Buccal infiltrations were then baseline heart rate recorded. The patient received 100% oxy- given and necessary dental treatment completed. Verbal post gen throughout the injection period and until baseline heart operative instructions were given to the parent and child. The rate was attained in the post-injection period. Nitrous oxide study phase of the treatment was videotaped using a standard was not administered at any time. After 15 minutes, the video camera mounted on the wall in the dental operatory. The lidocaine patch was removed and a greater palatine injection videotape of each session was independently reviewed later by two members of the pediatric dentistry faculty and the patient’s behavior during each injection evaluated according to the Table 2. Statistical Comparisons of Measurements of Pain 17 Response (Lidocaine Patch versus Topical Anesthetic Gel) Sounds, Eyes, Motor Scale as previously outlined by Wright (Table 1). Intra-rater reliability was established at 100% by Wilcoxon Sign Rank Paired t-Test reviewing a series of videotapes in a training session prior to Test P value P value evaluation of the study videotapes. The following parameters Faces pain scale .2573 .3621 were utilized to evaluate patient’s reported pain, physiological Visual analog scale .7329 .8258 pain, and observed patient pain: Heart rate change .2034 .2122 Reported pain / observed pain Heart rate change .0151• .0234• Faces pain scale: Each of the 5 faces on the Faces Pain Scale Topical as 1st injection is assigned a value from 1 (smiling) to 5 (crying). The use Heart rate change .6776 .7592 of the Faces Pain Scale in children has been validated as a Patch as 1st injection reliable indicator of pain following major surgery.18 Observed pain-sounds• .0027• .0016• Visual analog scale: The VAS is a 100 mm line anchored by Observed pain-motor .8438 .6898 the words “no pain” at 0 mm and by “worst pain possible” at 100 mm. Scoring is accomplished by measuring in mil- •Statistically significant

20 American Academy of Pediatric Dentistry Pediatric Dentistry – 23:1, 2001 Fig 2. Reported Pain Visual Fig 3. Heart Rate Change by Analog Scale Results Injection Order

• 1st injection gel: HR increase 18% Gel 33 mm 2nd injection patch: HR increase 9% P=.02 DentiPatch 34 mm • 1st injection patch: HR increase 15% 2nd injection gel:HR increase 14% P=.76 Paired t-test P=.83

limeters from 0 to the mark the child made representing 38.2mm) and was not statistically significant (P=.7329, t-test). the pain perceived during the injection. Nine children rated the injection which followed topical anes- Verbal rating: Upon completion of the second injection, the thetic as more painful, 9 rated injections following the lidocaine child was asked which side hurt more. patch more painful and 14 rated the injections the same. Per- Heart rate changes: Baseline heart rate and the highest heart centage heart rate change from baseline for all injections was rate in the post-injection period were recorded for each not statistically significant (P=.2122, t-test). However, when injection. The percent increase or decrease in heart rate the first injection followed topical anesthetic gel application, was calculated for each injection. An increase in heart rate the heart rate change for the second injection was significantly has been shown to be a reliable physiologic response to decreased (P=.0151, WSRT). Injections which followed perceived painful stimuli.19 lidocaine patch application resulted in less intense verbal indi- Sounds, eyes, motor scale: The score in each category ranged cations of pain compared to topical anesthetic gel for 12 of the from 1 (none) to 4 (intense). A lower score represents less 32 pairs of injections (Fig 1). Figure 1 indicates the differences physical reaction to the injection stimulus than does a between the scores of the Sound, Eyes, Motor Scale for the higher number. Wright17 reported that the SEM Scale patch and topical anesthetic gel. For example, for three chil- (Table 1) corresponded favorably to the Frankl Behavior dren the observed pain-sounds score for the patch was two Rating Scale. Two independent evaluators viewed the rankings lower than for the topical gel. Topical anesthetic gel videotapes and evaluated the patient’s behavior during each application resulted in less intense verbal indications of pain injection. Pain related behavior in the categories of sounds for 1 pair of injections. The observed pain-sounds result was and motor was rated. Eye indications of pain were not found to be highly statistically significant (P=.0027, WSRT, rated due to inability to accurately observe such signs on Table 2). Observed pain-motor was not statistically significant the videotape. Inter-rater reliability was excellent, as estab- (P=.8438, WSRT). lished by a kappa statistic of 96%. Discussion Results Results showed children made fewer sounds indicating pain Participants in the study had an average age of 9 years, 2 months when injections followed lidocaine patch application than in- (+ 30 months) with an age range of 6 years, 2 months to 15 jections which followed topical anesthetic gel application. This years, 9 months and included 17 females and 15 males. The finding is significant and should offer the patch as a viable op- numerical difference in the score for each child’s pair of injec- tion for reduction of discomfort during dental injections. Use tions was analyzed using the Wilcoxon Sign Rank Test and the of the lidocaine patch could lead to reduced stress for the child, paired t-test. Results of statistical analyses are shown in Table parents, staff, dentist, and other children in the office who may 2. There was no statistically significant difference between benefit through modeling. The use of each patient as his/her injections which followed topical anesthetic gel or the lidocaine own control helps support the findings since the variability in patch in the Faces Pain Scale ratings (P=.2573, WSRT). The a patient’s response to pain is addressed. The comparison of Visual Analog Scale mean value for topical anesthetic was 32.5 palatine injections also contributes to strength of the findings mm, the mean value for the lidocaine patch was 33.9 mm (+ since this is an injection that is perceived to be of relatively greater discomfort. Change in heart rate has been shown to be a reliable indicator of a patient’s response to pain. Results showed when the first injection followed topical anes- thetic gel, there was a significant lessening of heart rate increase for the second injection which followed patch application. Second injections have been found to be more painful than first injections.2 The results ob- tained indicate the patch was able to provide superior anesthe- sia, which negated the expected Fig 1. Individual Faces Pain Scale Results. Wilcoxon Sign Rank Test P=.26 increased heart rate.

Pediatric Dentistry – 23:1, 2001 American Academy of Pediatric Dentistry 21 change the amount of lidocaine in the patch. It was noted after removal of the lidocaine patch the area anes- thetized was not readily evident while tissue anesthetized by topi- cal anesthetic gel was easier to visualize. The incorporation of a dye or other indicator into the patch could facilitate injection. Since the present study was the first to evaluate the patch deliv- ery system in children, additional studies are needed to Fig 4. Individual Observed Pain-Sounds Results. Wilcoxon Rank Test P=.0027 investigate these modifications. The time required for maximum effectiveness of the Conclusions lidocaine patch presented some clinical problems. Several chil- 1. There was a statistically significant difference favoring the dren cried quietly during much of the 15 minute patch use of the lidocaine patch (20%) in the category of observed application period. The results of the study might be differ- pain-sounds. However, there were no statistically signifi- ent for very apprehensive children versus calm children and a cant differences in reported pain (Faces Pain Scale, Visual pre-operative assessment of the child’s anxiety level could be Analog Scale, Verbal Rating), overall heart rate increase, included in future studies to determine if the lidocaine patch or observed pain-motor when comparing the lidocaine is suitable for use in anxious children. The patch is easily dis- patch and topical anesthetic gel (20% benzocaine). lodged during the 15 minutes application period if not kept 2. When second injections followed lidocaine patch applica- dry. Further studies could determine if a shorter lidocaine tion, the increase in heart rate was significantly lessened. patch application period would provide the same results. 3. Although the DentipatchTM clearly has limitations in pe- Evaluation of the data gathered from the Faces Pain Scale diatric dentistry, further studies are needed to determine and the Visual Analog Scale indicates self-evaluation of pain, its clinical usefulness. while documented in several studies post-surgery, may not be a valid measurement of perceived pain in pediatric dental pa- References tients. In this study, the Faces Pain Scale and Visual Analog 1. Wilson S, Molina L, Preisch J, Weaver, J. The effect of elec- Scale were completed after the painful event while studies which tronic dental anesthesia on behavior during local anesthetic have found self-evaluation of post-surgery pain to be a reliable injection in the young, sedated dental patient. Pediatr Dent indicator of pain involve completing the scales during the pain- 21:12-17, 1999. ful event. 10,18 2. Martin M, Ramsay D, Whitney C. Topical anesthesia: dif- Many patients made no sounds indicating pain during in- ferentiating the pharmacological and psychological contribu- jections following lidocaine patch application until very near tions to efficacy. Anest Prog 41:40-47, 1994. the end of the injection. When sounds indicating pain were 3. Yaacob HB, Nor GM, Malek SN, Mahfuz MAB. The effi- observed following topical application, the sounds were often cacy of xylocaine topical anesthetic in reducing injection pain. made almost immediately upon needle insertion through mu- Med J Malaysia 38:59-61, 1983. cosa. A possible explanation may be that the lidocaine patch 4. Holst A, Evers H. Experimental studies of new topical anes- provided more profound anesthesia than topical anesthetic. thetics on the oral mucosa. Swed Dent J 9:185-191,1985. However, pain was experienced near the end of the injection when the volume of anesthetic exceeded the area anesthetized by the patch. The Sounds, Eyes, Motor Scale does not differenti- ate between the onset of indications of pain. The patch as manufactured is 8mm X 26mm. A change in the patch configuration to 16 mm X 13 mm might result in decreased pain during injection by reduc- ing pain caused if the volume of anesthetic injected exceeds the periphery of the patch as cur- rently manufactured. Such a patch modification would not Fig 5. Individual Observed Pain-Motor Results. Wilcoxon Sign Rank Test P=.8438

22 American Academy of Pediatric Dentistry Pediatric Dentistry – 23:1, 2001 5. Rosivack RG, Koenigsberg SR, Maxwell KC. An analysis of 13. Hersch EV, Houpt M, Cooper S, Feldman R. ef- the effectiveness of two topical anesthetics. Anest Prog ficacy and safety of an intraoral lidocaine patch. JADA 37:290-292, 1990. 127:1626-1634, 1996. 6. Pollack S. Pain control by suggestion. J Oral Med 21:89- 14. American Academy of Pediatric Dentistry: Guidelines. Lo- 95, 1966. cal anesthesia considerations during sedation. Pediatric Dent 7. Gill CJ, Orr DL. A double-blind crossover comparison of 20:49, 1998-1999. topical anesthetics. JADA 98:213-214, 1979. 15. Malamed, S. Handbook of local anesthesia, 4th ed. Mosby, 8. Keller, BJ. Comparison of the effectiveness of two topical an- 1997: 51-58. esthetics and a placebo in reducing injection pain. Hawaii 16. Houpt M, Heins P, Lanster I, Stone C, Wolff M. An evalu- Dent J 12:10-11, 1985. ation of intraoral lidocaine patches in reducing needle-in- 9. Kinchloe JE, Mealiea WL, Mattison GD, Seib K. Psycho- sertion pain. Compendium of Con Educ Dentistry 18:309-316, logical measurement on pain perception after administration 1997. of a topical anesthetic. Quintessence Int 22:311-315, 1991. 17. Wright GZ, Weinberger SJ, Marti R, Plotzke O. The effec- 10. LaMontagne LL, Johnson BD, Hepworth JT. Children’s tiveness of infiltration anesthesia in the mandibular primary ratings of postoperative pain compared to ratings by nurses molar region. Ped Dent 13:278-282, 1991. and physicians. Issues Compr Pediatr Nurs 14:241-247, 1991 18. Tyler DC, Tu A, Douhit J. Toward validation of pain mea- 11. Noven Pharmaceuticals DentiPatch Product Insert. July, surement tools for children: a pilot study. Pain 52:301-309, 1996. 1993. 12. Noven Pharmaceuticals DentiPatch Technical and Clinical 19. Dowling J. Autonomic indices and reactive pain reports on Monograph. September, 1996. the McGill Pain Questionnaire. Pain 14:387-392, 1982.

ABSTRACT OF THE SCIENTIFIC LITERATURE DAY CARE ATTENDANCE AND RISK OF ASTHMA DURING CHILDHOOD Both the incidence and prevalence of asthma among children have increased dramatically in the last three decades. Young children with older siblings and those who attend day care are at increased risk for which may in turn protect them from the development of allergic diseases, including asthma. In this study, 1035 children, followed since birth as part of the Tucson Children’s respiratory study, were evaluated to determine the relationship between a physician’s diagnosis of asthma and the prevalence of frequent wheezing to the number of siblings at home and attendance at day care during infancy. The presence of one or more older siblings at home protected against the development of asthma between age 6-13 as did attendance at day care in the first six months of life. Interestingly, while children with more exposure to older siblings or other children had more episodes of wheezing at age 2 than children with little or no exposure, they were less likely to have frequent wheezing at age 6-13. The authors conclude that exposure of young children to older children at home or other children at day care may protect against the development of asthma and frequent wheezing later in childhood. Comments: This paper presents a rather interesting conclusion that emphasizes the complex interactions between up- per respiratory infections in childhood and allergic phenomena such as asthma. It also offers yet another perspective on the health implications of early attendance at day care. CH Address correspondence to: Dr. Anne L. Wright, Respiratory Sciences Center, University of Arizona, College of Medicine, 1501 N. Campbell Ave, PO Box 245073, Tucson AZ, 85724-5073. Ball TM, Castro-Rodriquez JA, Griffith KA, Holberg CJ, Martinez RD and Wright AL. Siblings, day care atten- dance and the risk of asthma and wheezing during childhood. N Engl J Med 2000;343:538-543. 35 references

Pediatric Dentistry – 23:1, 2001 American Academy of Pediatric Dentistry 23