Comparison of acceptance, preference and efficacy between pressure anesthesia and classical needle infiltration anesthesia for dental restorative procedures in adult patients.

INTRODUCTION: Intraoral local anesthesia is essential for delivering dental care. Needless devices have been developed to provide anesthesia without injections. Little controlled research is available on its use in dental restorative procedures in adult patients. The aims of this study were to compare adult patients acceptability and preference for needleless jet injection with classical local infiltration as well as to evaluate the efficacy of the needleless anesthesia.
MATERIALS AND METHODS: Twenty non fearful adults with no previous experience of dental anesthesia were studied using split-mouth design. The first procedure was performed with classical needle infiltration anesthesia. The same amount of anesthetic solution was administered using MADA jet needleless device in a second session one week later, during which a second dental restorative procedure was performed. Patients acceptance was assessed using Universal pain assessment tool while effectiveness was recorded using soft tissue anesthesia and pulpal anesthesia. Patients reported their preference for the anesthetic method at the third visit. The data was evaluated using chi square test and student's t-test.
RESULTS: Pressure anesthesia was more accepted and preferred by 70% of the patients than traditional needle anesthesia (20%). Both needle and pressure anesthesia was equally effective for carrying out the dental procedures.
CONCLUSION: Patients experienced significantly less pain and fear (p<0.01) during anesthetic procedure with pressure anesthesia. However, for more invasive procedures needle anesthesia will be more effective.

INTRODUCTION

The principal aim of dental operator is to carry out the dental procedure with as little pain and discomfort as possible. One of the most distressing aspects of dentistry for the average dental patient is the fear and anxiety caused by the dental environment, particularly the dental injection, i.e., syringe and needle which is referred as “NEEDLE PHOBIA” or BLENOPHOBIA.[12] The feeling of needle being attached to a syringe and penetrating the oral mucosa is quite distressing and carries a negative impact on patient's psychology. Epidemiological studies have shown that most of the patients put off their dental visits primarily due to the fear of needles, pain and bodily injury from injection.[23456]

John F. Roberts introduced the jet injection syringe in 1933.[7] The introduction of needleless injection into the clinical use in 1947 was the first change in injection technique since Alexander wood's introduction of the needle in 1853.[8] It has been used for variety of procedures in both medical and dental fields. In the year 1973, Santangelo, Mott and Stevenson reported 83% patients suffering from leukemia preferred pressure anesthesia over conventional needle anesthesia for bone marrow aspiration and lumbar puncture. In addition, it has been successfully used for insulin delivery, regional and digital blocks, incision of abscess, aspiration biopsy of lymph nodes, repair of laceration, mass immunization, vasectomy, cryosurgery, curettage and cyst excision.[9]

The first dental study using needleless jet injector was reported by Margetis et al. in 1958.[10] Conventional pain control techniques often deal with the pharmacological/sensory component.[2] The dental restorative procedures requires a local anesthesia and the anesthetic procedures is most often perceived as invasive, painful due to needle phobia by the patients.[9] In response to this perceived aversion, pressure anesthesia was introduced and it inspired many dentists to carry number of clinical and epidemiological studies on human and animal subjects.[281112]

The most interesting thing with these needleless device is the use of pressure to force the anesthetic solution safely into oral tissues which is well-accepted by the patients.[79] The anesthetic solution infiltrates the tissue in the tiny droplet form which is immediately taken up by the myelin sheath of the nerve with an onset of action of approximately 1 ms. This amount is most effective in localizing its effect without producing an effect on systemic blood level hence helpful in cardiac patients. In dentistry it can be successfully used as anesthetic device for curettage and scaling, mental and nasopalatine blocks, cementing crowns, jackets, bands and clamps; copper tube impressions, gingivectomies, direct pulp injections, biopsies and pointing abscesses for incision and drainage procedures.[13]

The objective of the needless jet injection is to deliver local anesthesia without subjecting the patient to the unpleasant experience of facing the “needle” and to achieve adequate anesthesia that should be acceptable to the patients.[1] Further before it is likely to replace traditional needle injection, it should also be preferred by the patients.

Thus, the present study was carried out with the following objectives:

The primary aim is to compare patients acceptance and preference to needless jet injection with classical local needle infiltration for dental restorative procedures

The secondary aim is to evaluate the efficacy of the needleless anesthesia for dental restorative procedures.

MATERIALS AND METHODS

The permission for the study was taken from Institutional Ethics Committee. Informed written consent for carrying out the treatment and their willful participation in the study was taken from the patients prior to starting of treatment.

A total of 20 non-fearful adult patients having complete information about the design and purpose of the study were selected using following questionnaire and inclusion criteria:

Are you fearful about the procedure of treatment to be performed, not the treatment outcome?

Have you ever had significant anxiety before any medical treatment? (intramuscular injection/intravenous injections/routine check-up done by auscultation/ear, nose and throat).

Inclusion criteria

Patients in need of dental treatment for minimum three or more teeth; two of these teeth, bilaterally requiring similar dental restorative procedures such as:[14]

Vital pulp therapy

Class I/Class V restorations-Single surface restoration

Class II/Class III restorations-Multiple surface restorations.

The two teeth that had similar dental treatment requirements (e.g., two Class I/Class V restoration) will be treated as part of study using split mouth design during two dental visits

Non-fearful patients with no previous experience of dental anesthesia

Healthy patients with localized pathological process[15]

Patients with mild to moderate systemic diseases.[15]

Anxious, alcoholic patients, patients giving history of personality disorders, patients who abuse drugs, patients who did not demonstrate subjective signs of anesthesia or required a secondary injection or sedative measures to deliver dental treatment were excluded from the study. Prior to the scheduled dental procedure each patient was tested for local anesthesia sensitivity test. Universal pain assessment tool is a 10 mm scale, 0 represents no pain, pressure or discomfort whereas 10 marked the highest score.[16] This scale along with the following questionnaire [Table 1] was handed over to each patient before commencing the treatment. They were guided to record their subjective response to injection before, during and after the treatment.

Table 1

Format of the questionnaire/proforma used for data collection

In the first appointment, dental procedure was performed with classical needle infiltration anesthesia. All parts and preparation of injection but not needle was shown to the patient. Before commencing anesthetic procedure Electric pulp test (EPT) for the test tooth was carried out and the response was noted. Topical anesthetic gel (benzocaine 20%, Beutlich Pharmaceuticals LP, Waukegan, III for 2 min) was applied followed by delivery of anesthesia (Lidocaine 2% with epinephrine 1:80,000 Lignospan special, Steptodont, Saint-Maur-des-Fosses Cedex, France) using standard dental aspirating type syringe (Steptodont) and 25 mm gauge needle (Septoject, Septodont) as described by Malamed.[17] A 0.3 ml of anesthetic solution was discharged buccally to the apex and 0.1 ml lingually or palatally to the subjected tooth. The onset and duration of action of anesthesia was recorded using stop watch, each minute post-injection to determine the soft-tissue pain reaction at the buccal aspect of the tooth using tissue forceps[7] and pulp reaction of test tooth using pulp tester (Parkell, Model PT-20, Parkell Electronics Division, Farmingdale, New York, USA). In addition, other parameters were noted by the operator as mentioned in the questionnaire/proforma [Table 1] and restorative procedure was carried out. The patient was observed in the operatory until all the symptoms of soft-tissue anesthesia wore off. The total duration of anesthesia was measured from the time of onset till patient reported normal reaction at the soft-tissue.

The second appointment for the contralateral side was scheduled after 7 days. The same procedure was followed for MADA jet pressure anesthesia. The MADA jet system (MADA Medical Products, Inc., Carlstadt, NJ, USA) works on a principle of spring that compresses a small internal piston, producing high pressure and emits anesthetic solution of 0.1 ml/injection, through a calibrated orifice in a fine stream which easily penetrates the tissue similar to 25 gauge needle diameter and forms a wheal producing two important effects:

The pain from the insertion by needle and syringe is greatly diminished

The second injection will noticeably decrease the pain caused by the volume of anesthetic injected in the tissue with a needle and syringe.

During these two dental visits, data was also recorded as:

Type of restoration (dental procedure)

Location of anesthetic administration-Buccal/lingual/interproximal

Type of the tooth-Incisor/canine/1st molar/2nd molar.

The effectiveness of depth of anesthesia of these two different anesthetic technique was analyzed using this data.

The patients were called after 10 days for review. During this visit, they were asked to give preference for the anesthetic technique for future dental treatment 1st /2nd /both/none. This question was designed to measure the patient's preference for method of anesthesia delivery.

Continuous variables were summarized as mean and standard deviation (SD) and categorical variables were summarized as frequencies and percentages. Difference between proportions in the two techniques was tested by Chi-square test. Student's t-test was used for testing the difference between the means in the two techniques. Data was analyzed using statistical software STATA, Version 10.1, 2009 (STATA Corp, Texas 77845, USA).

OBSERVATIONS AND RESULTS

Mean (±SD) age of the patients was 24.6 (±10.03) years with a range of 16-60 years. There were 9 male (45%) and 11 females (55%) participated in this study. The restorative procedures carried out in this study were 16 vital pulp therapies and 4 restorations (3-Cl I compound; 1-Cl II) on premolar and molar teeth [Table 2].

Table 2

Distribution of treatment procedures by tooth

Acceptance of anesthetic method

The acceptance of the pressure anesthesia (MADA jet) for patients requiring restorative procedures in comparison with the classical needle infiltration anesthesia is presented in Table 3. In general, most of the patients reported positive experiences for the pressure anesthesia (P < 0.001 except for discomfort,). Patients experienced significantly more discomfort (P < 0.001) during injections for pressure anesthesia as compared to classical infiltration; whereas after anesthetic procedure the discomfort was statistically non-significant (P = 0.46). Patients experienced significantly less pain and fear (P < 0.01) during anesthetic procedure with pressure anesthesia. However, operator noted significantly more bleeding from mucosa (P = 0.007) at the injection site with pressure anesthesia. Patients reported no significant difference (P = 0.08) for both the techniques regarding bad taste. None of the patients reported post-operative swelling at the site of injection.

Table 3

Acceptance of anesthetic methods

Preference for anesthetic method

At the third appointment, out of 20 patients, 14 patients (70%) stated that they preferred the pressure anesthesia (MADA jet) over classical needle infiltration whereas two patients (10%) gave preference for both the techniques.

Effectiveness of Jet injection

The time of onset of action for pressure anesthesia was less when compared to classical needle infiltration (P < 0.001) [Table 4]. However, the total duration of anesthesia was significantly more (P < 0.001) with classical needle infiltration (mean 50 ± 9.32 min) when compared to pressure anesthesia (20.75 ± 3.53 min). None of the procedures required additional anesthesia. The readings for EPT showed that pulpal anesthesia with classical needle infiltration was significantly more (P < 0.001) profound than with pressure anesthesia.

Table 4

Effectiveness of jet injection

DISCUSSION

Pain control during dental operative procedures is very challenging task for the clinician. Pain control using local anesthetics is widely accepted and use of “needle” for administration is considered to be a gold standard; even though, most of the patients are having fearful attitude toward it. To develop a more positive attitude of the patient toward dental procedure adequate anesthesia is essential. Painless and needless anesthesia administration will further enhance patient's co-operation and alleviate his fear. Hence this study was conducted to compare patients’ acceptance and preference to needleless pressure anesthesia with classical local needle infiltration and to evaluate the efficacy of the needleless anesthesia for dental restorative procedures.

In our study, 20 non-fearful adult patients requiring bilaterally similar dental restorative procedures were selected. The study was carried out using split-mouth design in two dental visits using classical needle anesthesia and pressure anesthesia. This split-mouth design offers potential saving in the resources. This design removes all components related to differences between subjects from the treatment comparisons thus reducing error variance (noise) and subsequently obtaining a more powerful test.[1819]

Various anesthetic solutions such as lidocaine, articaine, mepivacaine with different concentration ranging from 2% to 5% have been used in previous studies.[714] The type amount and concentration of anesthetic solution along with the amount of vasoconstrictor affect the anesthetic result. Bennett et al. in their radiographic and histologic study supported pressure anesthesia as it provides penetration and infiltration roughly comparable to that produced by needle injection to near 1 cm depth, with the use of quantities up to 0.2 ml/injection; as it is the concentration gradient of anesthetic solution diffusing into the surrounding tissue determines how much anesthetic reaches a nerve.[8] Dabarakis et al. in their study found that 3% mepivacaine used with pressure anesthesia did not produced pulpal anesthesia.[7] Hence, in our study, 2% lignocaine with epinephrine 1:80,000 was used with both the anesthetic techniques for completion of dental restorative procedures. According to literature provided by manufacturer very little anesthetic solution is needed to form a wheal which effectively gives adequate anesthesia to carry out restorative procedures. Hence, 0.3 ml of anesthetic solution was deposited buccally and 0.1 ml lingually and no supplementary anesthesia was required.

In the first visit, classical needle anesthesia was administered as it is a gold standard as inadequate anesthesia leads to the development of dental fear.[414] Thus for ethical reasons to avoid the development of dental fear the administration of highly efficacious needle anesthesia was delivered during the first visit and pressure anesthesia in the second visit. Patient's acceptance was assessed using Universal pain assessment tool and the effectiveness of anesthesia was done using soft-tissue anesthesia and EPT. Universal pain assessment tool comprises of Verbal descriptor scale, Wong-Baker Facial grimace scale and activity tolerance test. It was found to be more sensitive as compared to Visual analog scale[202122] and hence it was used in this study.

Our study found that 70% patients preferred pressure anesthesia; whereas 10% patients gave preference for both the anesthetic techniques. It might be possible that needle phobic patients might respond more positively to pressure anesthesia. In this study, patients reported significantly more discomfort (P < 0.001) during injection for pressure anesthesia; this may be due to the difficulty in the positioning of anesthetic equipment. The results of our study are in broad agreement with the previous study done by Saravia and Bush (1991)[9] who reported 75% pediatric patient's preference for pressure anesthesia over the conventional method. Munshi et al. (2001) in their study also reported 93% patients acceptance for pressure anesthesia.[2] EPT results showed more profound pulpal anesthesia with needle infiltration. But simple restorative procedures such as Class I, Class II and vital pulp therapies can be comfortably completed with pressure anesthesia provided the procedure is completed in 20-25 min. However, for pulpectomy procedures it can be used for intrapulpal injections. These results are in accordance with the study of Dabarakis et al. (2007).[7]

The results of our study are contrary to Arapostathis et al. (2010) who reported more negative experiences with pressure anesthesia using INJEX as 73% children preferred the traditional needle method.[14] Similarly, Dabarakis et al. (2007) in their study reported only 17.6% patients preference for pressure anesthesia; whereas 52.8% patients preferred classical injection technique.[7] In these studies, the anesthetic device used was INJEX in which the anesthetic delivering segment forms a 90° angle with the main body contrary to MADA jet. Its delivery segment forms a 45° angulation with gingiva producing better and easy positioning with complete contact with gingiva, less pressure during administration resulting in less leakage and less bad taste compared to other pressure anesthesia systems which form 90° angle.[14]

This pressure anesthesia offers advantages such as no needle-stick injury, decreased fear of procedure, faster drug absorption at the injection site and is autoclavable. However the major disadvantage being the initial cost of the equipment, bleeding at the site of injection, popping sound while injecting and most of the clinicians are not familiar with its use.[223]

Due to rigorous standardization protocols it was difficult to get a large number of patients in stipulated time period; However, post-hoc analysis revealed that this study had sufficient power (>99%) to detect a significant difference in acceptability parameters (e.g., pain, fear, discomfort, bad taste) in the two anesthetic techniques. Two anesthetic techniques were performed at two different visits; hence acclimatization to the anesthetic procedure may have caused reduced fear/pain/discomfort during the second visit.

Other methods of enhancing effects of local anesthesia have been earlier evaluated with various degrees of success. The important parameter in improving the quality of anesthesia is the role of premedication. Studies have proved that pre-operative medication improves the efficacy of inferior alveolar nerve block[24] and maxillary infiltrations.[25] In addition, other injection techniques like X-tip intraosseous injections have delivered high success rate in achieving profound pulpal anesthesia in patients with irreversible pulpitis.[26]

In this study, though neither the post-operative complications were reported by the patients immediately nor confirmed objectively by the operator. Thus to quantify this factor further studies requiring immediate post-operative examinations with sufficiently large number of patients are required. From the literature review of pressure anesthesia; it is noted that no instances of infections were reported even in immunosuppressive patients. Hence, in today's clinical scenario of rigid infection control, this pressure anesthesia device can play a vital role; however controlled microbiological studies may yield better information. This technique may be particularly beneficial in reducing fear from needle view and contribute to limited dose administration which is proved to be beneficial for patients suffering from systemic disorders.

CONCLUSION

Patients experienced significantly less pain and fear (P < 0.01) during anesthetic procedure with pressure anesthesia. In our study sample, majority (70%) of patients preferred pressure anesthesia, only few (20%) patients preferred needle anesthesia and 10% patients preferred both the techniques. In terms of efficacy, pressure anesthesia was successful in all the restorative procedures and vital pulp therapies, provided procedure was completed in 20-25 min. Though pressure anesthesia cannot replace completely the classical needle anesthesia it can be recommended as an alternative and choice of anesthesia in clinical procedures of shorter duration.