Dabarakis.qxd

Q U I N T E S S E N C E I N T E R N AT I O N A L Needle-less local anesthesia: Clinical evaluation
of the effectiveness of the jet anesthesia Injex in
local anesthesia in dentistry
Nikolaos N. Dabarakis, DDS, PhD1/Veis Alexander, DDS, PhD1/ Anastasios T. Tsirlis, DDS, PhD2/Nikolaos A. Parissis, DDS, PhD2/ Objectives: To clinically evaluate the jet injection Injex (Rösch AG Medizintechnik) using 2
different anesthetic solutions, and to compare the jet injection and the standard needle injection techniques. Method and Materials: Of the 32 patients in the study, 10 received
mepivacaine 3% anesthetic solution by means of the jet injection technique, while the remaining 22 patients received lidocaine 2% with epinephrine 1:80,000 by the same method. The 14 patients in whom pulp anesthesia was achieved were selected for an additional evaluation of the pulp reaction using standard needle injection anesthesia. The differences between the 2 compounds with Injex were statistically evaluated by means of independent-samples t test analysis. The differences between subgroups receiving both jet injection and needle injection anesthesia were evaluated by means of paired t test analysis. Results: The administration of mepivacaine 3% using Injex did not achieve pulp
anesthesia in any of the 10 patients, although the soft tissue anesthesia was successful.
The administration of lidocaine with epinephrine using Injex resulted in pulp anesthesia in only 14 patients; soft tissue anesthesia was observed in all patients of this group. There was no statistically significant difference between Injex and the needle injection technique in onset of anesthesia. However, the duration of anesthesia was significantly longer for the needle infiltration group than for the Injex injection group. Conclusion: The anesthetic
solution should be combined with a vasoconstriction agent when the Injex technique is implemented. (Quintessence Int 2007;38:881.e572–576) Key words: epinephrine, jet injection, lidocaine, local anesthesia, mepivacaine, needle-
One of the major problems in dental prac- sight of a needle during administration of tice is the fear of the dental injection, which local anesthetic than by the ensuing treat- most patients exhibit during treatment.
Patients are often more distressed by the effectiveness of anesthetic solutions and the quality of dental needles, the method unchanged. A needle connected to a syringe Lecturer, Department of Oral Surgery, Implantology, and remains a necessity, and the realization that it will penetrate the oral mucosa is chilling for 2Associate Professor, Department of Oral Surgery, Implantology, most patients.1 To reduce and eliminate pain and Roentgenology, Dental School, Aristotle University of and thus alleviate the fear of the injection, cli- nicians have resorted to applying anesthetic 3Private practice, Thessaloniki, Greece.
Correspondence: Dr Nikolaos Dabarakis, 18 Varnali Str., 57004
proximal to the site at which the syringe injec- Michaniona, Greece. Fax: +30 23920 21249. E-mail: nikosd@ Q U I N T E S S E N C E I N T E R N AT I O N A L D a b a r a k i s e t a l
Therefore, the challenge is to use a less designed exclusively for submucosal injec- invasive method of administration rather than tions. The Injex injector is the size of a ball- to discontinue the use of local anesthesia. A point pen, lightweight (approximately 75 g), step in that direction is the application of and reusable (Fig 1). A reusable transporter techniques whereby the anesthetic solution is a dosing tool designed for transferring liq- is introduced into the tissue without the use uid medication from cylinder cartridges to of a needle.3 Needle-less local anesthesia the Injex system ampoules (sterile- packed with a jet injection device has been pro- plastic ampoules) (Fig 2); the ampoule filled with the medication is screwed into the injec- anesthetic solution is forced under high pres- tor (Fig 3). The reset box is used for storing the injector. When the reset box is closed, a through the mucosa. The current opinion is the injector for recharging (Fig 4). The pre- that this technique can be used only for sur- pared injector is placed firmly on the firm face anesthesia and thus is supplementary to attached gingiva at a 90-degree angle. The the standard infiltration techniques. It is intended to reduce the discomfort or pain of noise. With a short press on the trigger, the the ensuing syringe injection and ultimately injection is completed in a fraction of a sec- to replace the standard syringe injection ond. After the anesthetic has been applied, technique under specific conditions.
clinically evaluate the outcome of the jet injection Injex (Rösch AG Medizintechnik) placed lightly over the buccal mucosa corre- using 2 different anesthetic solutions and to sponding to the apex of a healthy tooth (Fig compare the jet injection and the standard 5); the patient was instructed to stay still, and needle injection techniques using the same the release button was pressed, discharging duration of the anesthesia were recorded at each minute postinjection to determine (1) the pulp reaction of the test tooth and (2) the METHOD AND MATERIALS
soft tissue pain reaction at the buccal apex of the tooth. The pulp reaction was measured Thirty-two patients admitted to our depart- with the aid of a digital pulp tester (Pulppen ment for tooth extractions were included in DP2000 Digital, Dental Elecronic); the soft the study. To obtain the most objective out- tissue pain reaction was tested by means of was used; neither the patient nor the opera- The patients were divided into 2 groups.
Ten patients (group A) received mepivacaine pound. Each patient signed a relevant con- sent, and a brief description of the thera- Espe) using the jet injection technique. The remaining 22 patients (group B) received lidocaine 2% anesthetic solution with 1:80,000 ments, was given. In addition, it was con- epinephrine (Lignospan special, Septodont) firmed that the patient could hear the char- acteristic “pop” sound when the release but- ton of the Injex devise was pressed. All injec- B1) who responded positively to pulp anes- thesia were selected for an additional evalua- tion of the pulp reaction 1 week postopera- tively using the standard needle injection demands operator familiarity and provides the use of 1-use sterilized compartments.
amount of anesthetic solution (0.3 mL) was The manufacturer claims that the device was Q U I N T E S S E N C E I N T E R N AT I O N A L D a b a r a k i s e t a l
technique as done previously. The recorded The statistical significance of the differ- and B) with Injex was evaluated by means of independent-samples t test analysis. The statistical significance of the differences ed by means of paired t test analysis. The sig- nificance level for each test was P < .05.
Dosing tool used to transfer medication to the Injex ampoules.
The administration of mepivacaine 3% with Injex (group A) had no effect on pulp anes- thesia in any of the 14 patients. However, soft group, presenting a rapid onset (< 1 minute) and duration of 6.10 ± 4.04 minutes.
The administration of lidocaine with epi- nephrine with Injex (group B) resulted in pulp anesthesia in only 14 patients, while soft tis- patients of this group. Onset of pulp anes- thesia took 2.59 ± 2.51 minutes, and it lasted 8.90 ± 10.02 minutes. Onset of soft tissue anesthesia was rapid (< 1 minute), and the Statistical analysis showed that the Injex Fig 4 Placement of the injector into the reset box.
achieved significantly longer duration of soft tissue anesthesia than that in the mepiva- caine group (6.10 ± 4.04) (P < .05; independ- ent-samples t test, t = –0.379, df = 30).
injection techniques (groups B1 and B2) was compared using only lidocaine and epineph- rine solutions since mepivacaine had no pos- itive effect on tooth pulp. Statistical analysis showed no statistically significant difference in the onset of anesthesia (4.07 ± 1.94 for Fig 5 Placement of the injector vertically on the
group B1 versus 3.71 ± 1.20 for group B2; P = .58 > .05; paired t test, t = 0.563, df = 13).
However, the duration of anesthesia was sig- nificantly longer for the needle infiltration group (B2) than for the Injex injection tech- nique (21.71 ± 4.63 minutes versus 14.00 ± 9.24 minutes, respectively; P = .001 < .05; paired t test, t = –4.170, df = 13).
Q U I N T E S S E N C E I N T E R N AT I O N A L D a b a r a k i s e t a l
soft tissue anesthesia. Mepivacaine’s inade- received anesthesia by means of the Injex technique was also recorded, using a pain- explained by its rapid mechanical absorption control method. Fifty percent of patients that occurs after its fast application under reported discomfort or pain before the spray of pressure; since there is no vasoconstrictor the anesthetic and from the contact of the tip action, it quickly enters general circulation.
of the device with the oral mucosa before Pharmacokinetic studies have demonstrated injection; 17.6% experienced pain during injec- that peak anesthetic blood levels of 3% mepi- tion of the anesthetic; and 32.3% reported feel- vacaine exceeded that of an equal volume of ing dread or fear from the explosion of the injector as it released the anesthetic. In 14.6% threefold after maxillary infiltration injec- of the patients, there was limited bleeding at tions.6,7 In addition, studies on intraosseous the injection site. Finally, 11.8% of patients experienced intense pain in the area of the shown lower success rates when anesthetic injection after the anesthesia subsided. solutions that do not contain vasoconstric- After their experience with Injex, patients tors or have reduced vasoconstrictor con- were asked about their future choice of local anesthesia technique: 17.6% expressed their Apart from pulp anesthesia, in this study, lidocaine with epinephrine was superior to ferred the classic injection with needle- mepivacaine in soft tissue anesthesia, as syringe; 29.6% expressed no preference.
well. The duration of anesthesia achieved using the Injex technique with lidocaine with epinephrine anesthetic solution was signifi- DISCUSSION
studies12,13 where mepivacaine’s lower anes- John F. Roberts introduced the jet injection thetic success rate was mentioned. The pres- syringe in 1933, producing a prototype of the ence of a vasoconstrictor in the anesthetic cartridge has a major influence on the dura- refined these syringes, and modified modes tion of anesthesia.14 The injection of epi- have found their way into dental application.5 nephrine combined with a local anesthetic In 19584 the first publication on its use in into the oral mucosa inhibits the compound’s dentistry stated that adequate anesthesia absorption by vasoconstricting action of the could be observed in gingiva, lips, and the inner part of the cheek by administration of small amounts of local anesthetic solutions.
anesthetic solution used with the Injex tech- The benefits of the jet injection technique striction agent. However, even with the use of patient’s psychologic barriers and anxieties lidocaine with epinephrine as an anesthetic by eliminating the view of the needle. In addi- compound, the effectiveness of this tech- tion, it is an easy-to-use and time-saving nique is still limited; in this study, 8 of 22 application that carries no risk of infection.
cases did not achieved pulp anesthesia.
Thus, the use of Injex should be confined bleeding, trauma and pain to the injection somehow to only soft tissue anesthesia of site, and increased patient apprehension, enhanced by the fact that 52.8% of patients Injex did not achieve pulp anesthesia, but only Q U I N T E S S E N C E I N T E R N AT I O N A L D a b a r a k i s e t a l
CONCLUSIONS
7. Goebel W, Allen G, Randall F. Circulating serum lev- els of mepivacaine after dental injection. Anesth Apart from some mild complaints, the Injex 8. Schleder JR, Reader A, Beck M, Meyers WJ. The peri- technique exhibits all the advantages of jet odontal ligament injection: A comparison of 2% anesthesia mentioned in this study. Although lidocaine, 3% mepivacaine, and 1:100,000 epineph- it is not a panacea, it is a useful adjunct to rine to 2% lidocaine with 1:100,000 epinephrine in local anesthesia. The jet injection technique human mandibular premolars. J Endod 1988;14: may be particularly beneficial in pediatric 9. Johnson GK, Hlava GL, Kalkwarf KL. A comparison of dentistry, where its use would reduce fear periodontal intraligamental anesthesia using etido- from needle view and contribute to limited caine HCl and lidocaine HCl. Anesth Prog 1985; dose administration, which is an important issue in the local anesthesia in young chil- 10. Kaufman EL, LeResche L, Sommers E, Dworkin SF, dren.16 The result of this study showed that Truelove EL. Intraligamentary anesthesia: A double- the anesthetic solution used with the Injex blind comparative study. J Am Dent Assoc 1984; technique should be combined with a vaso- 11. Gray RJ, Lomax AM, Rood JP. Periodontal ligament injection: Alternative solutions. Anesth Prog 1990; 12. Replogle K, Reader A, Nist R, Beck M, Weaver J, Meyers WJ. Anesthetic efficacy of the intraosseous REFERENCES
injection of 2% lidocaine (1:100,000 epinephrine) and 3% mepivacaine in mandibular first molars.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1. Garellek AL. Clinical evaluation of a jet injector for local anaesthesia. J Can Dent Assoc 1967;33: 13. Petersen JK, Luck H, Kristensen F, Mikkelsen L. A comparison of four commonly used local anal- 2. Arefian D, Henry J, Whitehurst V. Clinical evaluation gesics. Int J Oral Surg 1977;6:51–59.
of a syringe-loaded gun. Oral Surg 1972;33: 14. Jastak JT, Yagiela JA. Vasoconstrictors and local anesthesia: A review and rationale for use. J Am 3. Stephens RR, Kramer IRH. Intra-oral injections by high-pressure jet. Br Dent J 1964;117:465–481.
15. Smith GN, Pashley DH. Periodontal ligament injec- 4. Margetis P, Quarantillo E, Lindberg R. Jet injection of tion: Evaluation of systemic effects. Oral Surg Oral local anaesthesia in dentistry. U S Armed Forces 16. Goodson JM, Moore PA. Life-threatening reactions 5. Pollack BF, Crasson W, Milling L. A comparison of after pedodontic sedation: An assessment of nar- dental jet injection syringes. N Y State Dent J cotic, local anesthetic, and antiemetic drug interac- tion. J Am Dent Assoc 1983;107:239–245.
6. Goebel WM, Allen G, Randall F. The effect of com- mercial vasoconstrictor preparations on the circu- lating venous serum level of mepivacaine and lido-

Source: http://yourdent.co.il/files/clinical_evaluation_of_injex.pdf