Original Article · Originalarbeit Forsch Komplementmed 2014;21:94–98 DOI: 10.1159/000362140

Published online: March 28, 2014

An Earplug Technique to Reduce the Gag Reflex during Dental Procedures Yusuf Ozgur Cakmaka Ömer Ozdogmusb Yumusan Günayc Bahadır Gürbüzerd ˘ Kasparf Hüsniye Hacıoglug Emre Tezula¸se Elif Cigdem a

Department of Anatomy, Rumelifeneri Campus, School of Medicine, Koç University, Department of Anatomy, School of Medicine, Marmara University, c Section of Prosthodontics, d Section of Oral and Maxillofacial Surgery, Department of Dentistry, Haydarpasa Training Hospital, Gülhane Military Medical Academy, e Dental Academy, Private Practice, Kadikoy, f Department of Biostatistics, School of Medicine, Yeditepe University, Kayısdagi, g Department of Anatomy and Institute of the Neurological Sciences, School of Medicine, Marmara University, Istanbul, Turkey

Keywords Gag reflex · Earplug · Trigeminal · Glossopharyngeus · Oral

Schlüsselwörter Würgereflex · Ohrstöpsel · Trigeminal · Glossopharyngeus · Oral

Summary Background: The gag reflex is a frequent problem occurring during dental treatment procedures, especially while making impressions of the maxillary teeth. The present study aims to evaluate the efficacy of a simple earplug as an external auditory canal stimulator to supress the profound gag reflex and as a second step, to map areas of the oropharynx suppressed by this technique. Methods: In the first step of the study, 90 patients who had a gag reflex during the impression procedure were allocated to a study group, a sham group, and a control group for evaluating the efficacy of the earplug technique. Second, 20 new patients with a gag reflex were included in order to map the oropharnygeal areas suppressed by this technique. Results: The severity of the gag reflex was reduced in the earplug group (but not in the sham or the control group). The affected area included the hard palate, uvula, and the tongue but not the posterior wall of oropharynx. Conclusion: An earplug technique can be a useful, practical, and effective tool to overcome the gag reflex during oral procedures, such as impression procedures of maxillary teeth.

Zusammenfassung Hintergrund: Der Würgereflex stellt ein häufiges Problem bei Zahnbehandlungen dar, insbesondere bei Abdrücken der Zahnreihe des Oberkiefers. Die vorliegende Studie erfasst daher die Wirksamkeit von herkömmlichen Ohrstöpseln zur Stimulierung des äußeren Gehörgangs, um den Würgereflex zu unterdrücken. Zudem werden Bereiche des Mundrachens erfasst, die bei dieser Technik lahmgelegt werden. Methodik: Im ersten Schritt der Studie wurden 90 Patienten mit Würgereiz während der Zahnabdruck-Prozedur einer Untersuchungsgruppe, einer Placebogruppe und einer Kontrollgruppe zugeordnet. In einem zweiten Schritt wurden 20 weitere Patienten mit Würgereiz eingeschlossen, bei denen die Bereiche des Mundrachens erfasst wurden, die beim Einsatz von Ohrstöpseln lahmgelegt werden. Ergebnisse: Die Intensität des Würgereflexes war in der Untersuchungsgruppe niedriger im Vergleich zur Placebo- und Kontrollgruppe. Die betroffenen Bereiche umfassten den Gaumen, das Gaumenzäpfchen sowie die Zunge, jedoch nicht die Hinterwand des Mundrachenraums. Schlussfolgerung: Die Verwendung von Ohrstöpseln kann eine nützliche, praktische, und wirksame Maßnahme sein, um den Würgereflex, der bei zahnärztlichen Eingriffen, insbesondere bei Abdrücken der Zahnreihe des Oberkiefers ausgelöst wird, zu unterbinden.

© 2014 S. Karger GmbH, Freiburg 1661-4119/14/0212-0094$39.50/0 Fax +49 761 4 52 07 14 [email protected] www.karger.com

Accessible online at: www.karger.com/fok

Assoc. Prof. Yusuf Ozgur Cakmak, MD, PhD Anatomy Department Z38 Rumelifeneri Campus Sariyer School of Medicine, Koç University 34450 Istanbul, Turkey [email protected]

Downloaded by: NYU Medical Center Library 128.122.253.212 - 5/16/2015 12:23:07 PM

b

The gag reflex (GR) can be a frequent problem in dental procedures and occuring especially during impression procedures of the maxillary teeth. Although it is a normal reflex to protect the airway, including the posterior oropharynx and the upper gastrointestinal tract, in some individuals it may be exaggerated. The origin of gagging has been categorized as either a somatic type, initiated by sensory nerve stimulation from direct contact, such as touching trigger areas (tongue, certain parts of the palate) that can induce a reflex, or as a psychogenic type, originating in the higher centers of the brain that can be influenced by sight, sound, smell, or thought without direct contact [1, 2]. Several different strategies have been used to overcome the GR, including auricular acupuncture, palm pressing devices, or nerve block anesthesia [3–5]. However, current clinical applications of these methods are often not practical. An anesthetic block of the glossopharyngeal nerve (the afferent arch of the GR) can be considered as an invasive technique that requires additional anesthetic injection and can only be used by experienced dentists. The palm pressure technique seems to be a noninvasive technique, but it requires specific pressure devices and in some individuals it may be hard to find the correct point without using a specific device. Although auricular acupuncture is an effective method to overcome the GR, it may not be accepted by all patients and cannot be used by every dentist. Because of the indicated limitations of those different techniques, the GR is still one of the most significant problems for dentists while making impressions of the maxillary teeth. Although the glossopharyngeal nerve is considered to be the main afferent pathway for GR, which contributes to oropharyngeal mucosa sensation, tactile stimulation from areas innervated by the trigeminal nerve, such as the anterior faucial pillars, the base of the tongue and the soft palate may also elicit the GR [4–9]. It is worth noting that the trigeminal nerve allows for paradoxical preservation of the GR after a glossopharyngeus lesion [10]. The oropharyngeal areas innervated by the trigeminal nerve also overlap the external ear; sensation from the external auditory canal (EAC) and adjacent structures travels along 4 cranial nerves (V, VII, IX, and X) as well as the upper cervical plexus. All of these signals terminate in the nucleus of the spinal tract of the trigeminal nerve in the brainstem [7, 8, 11, 12]. According to current literature, the messages from oropharyngeal areas and the skin of the ear may merge at the different anatomical levels including the cortex and brainstem: It has been reported that oral, pharyngeal, and laryngeal inlet cancers can produce referred pain over the skin of the EAC [6]. Diseases of the mouth and face are the most frequent sources of referred otalgia, and the trigeminal nerve with its spinal tract nucleus is the most frequent pathway for referred otalgia. It is worth stressing that the representation of the ear in the somatosensory cortex is unique among the body parts. Al-

Earplug Technique to Reduce Gag Reflex

though the face, neck, thorax, and limbs are represented by distinct areas in the somatosensory cortex, this is not the case for the somatosensory representation of the ear. Nihashi et al. [13] demonstrated that the skin of the ear is represented by distinct areas distributed over areas of the somatosensory cortex that represent the head and neck. Such a unique representation of the ear may account for the referred sensations that relate the oropharyngeal areas to the ear. In addition to these documented anatomical paths relating to referred pain from oropharyngeal areas (including the laryngeal inlet) to the skin of the EAC and the pinna, reciprocal interactions have also be reported in literature. Cerumen (ear wax), located in the EAC, can trigger chronic cough because the referred irritation represents the larygeal inlet; thus, chronic cough relief can be achieved by the removal of the cerumen [14]. Moreover, it has been shown that auricular acupuncture points become ineffective in a denervated ear; therefore it can be concluded that the effect of stimulating auricular points occurs through auricular nerves which also innervate EAC [15]. On the basis of the available evidence, it can be theorized that stimulation via EAC triggered by an earplug may influence or block sensory pathways of the GR within the somatosensorial cortex, and/or at the brainstem and/or as an antidromic stimulation of the neuronal pathways of the oral referred pain (otalgia) over the EAC skin. In a first step, this study evaluated the use of a simple earplug (which can be obtained and easily used by any dentist) stimulating the external ear and supressing the profound GR that was generated by making impression of the maxillary teeth. As a second step, the study mapped the oropharnygeal areas from which the GR could be suppressed.

Methods The study was performed at the clinics of Gülhane Military Medical Academy, Haydarpasa Training Hospital, Department of Dentistry, Section of Prosthetic Dentistry in Istanbul, Turkey. The trial protocol has been approved by an ethical committee and meets the standards of the Declaration of Helsinki in its revised version of 1975 and its amendments of 1983, 1989, and 1996. Subjects Patients, who on previous occasions had demonstrated difficulties in accepting the procedure of making impressions of maxillary teeth due to a severe GR, were invited to participate in our study. The patient inclusion criteria involved the following 4 statements: 1–3, as in the acupuncture study on GR by Rosted et al [1] and the fourth added for standardization of the present study. 1. Inability to accept dental treatment on a previous occasion due to a severe GR. 2. Current dental treatment requires a maxillary irreversible hydrocolloid impression to be taken. 3. The individual is able to give informed consent. 4. Patients with GR severity were assigned to a gagging severity index (GSI) III–IV (for standardization of the baseline severity in between groups of step 1).

Forsch Komplementmed 2014;21:94–98

95

Downloaded by: NYU Medical Center Library 128.122.253.212 - 5/16/2015 12:23:07 PM

Introduction

Table 1. Gagging severity index (GSI)

The gagging reflex is I Very mild, occasional and controlled by the patient II Mild, and control is required by the patient with reassurance from the dental team III Moderate, consistent and limits treatment options IV severe and treatment is impossible V very severe; affecting patient behaviour and dental attendance and making treatment impossible

Table 2. Gagging prevention index (GPI)

Treatment management method employed I Obtunded gag reflex; treatment successful II Partially controlled gag reflex; all treatment possible III Partially controlled gag reflex but frequent gagging; simple treatment possible IV Inadequately controlled gag reflex; simple treatment unable to be completed V Gag reflex severe; no treatment possible

Assessment of Gagging Severity The GR evaluation was performed by the same dentist for all the patients. The GR assessment was undertaken prior to the insertion of the earplug using GSI (table 1), which assesses the magnitude of the GR, and again after inserting the earplug and the dental impression, by using the gagging prevention index (GPI) (table 2), which assesses the effectiveness of the treatment, as decribed by Dickinson and Fiske [16]. Procedure Each group was evaluated for GR severity by using GSI. The statistician and the patients were blind to the method. Allocation was performed in order; when one group finalized, the other initiated. Step 1: After the GSI evaluation, the earplugs (Moos Cosmetics Ltd., Istanbul, Turkey; fig. 1a) were inserted bilaterally into the EAC of the study group patients who were asked to wait with the earplugs in their ears in the patients’ room for 10 min. In the sham group, stick-on metal spherical pellets, which are designed for compressive stimulation over acupuncture points (fig. 1c), were stuck bilaterally onto the forehead of the patients (over the impression of the temporal line of the frontal bone, 1 cm above the eyebrows; fig. 1c) as a forehead skin stimulation for 10 min. After the GSI evaluation, the patients in the control group were also asked to wait in the patients’ room for 10 min, without applying the earplug or stick-on metal sphere pellets on the forehead. After 10 min, patients of all of groups (earplug, sham, and control) were taken to the treatment room for making the maxillary irreversible hydrocolloid impression; their GR was reevaluated by GPI (table 2) . The earplugs and stick-on metal sphere pellets were not taken out during the reevaluation.

96

Forsch Komplementmed 2014;21:94–98

Fig. 1. a Earplugs; b mapped areas: maxillary area (MX), glossopharyngeus area (GLO), mandibular division of trigeminal nerve area (MN), maxillary and glossopharyngeal nerve overlap area (MX-GLO); c stickon metal sphere and its sticking area on forehead indicated by white arrows.

Step 2: Four different areas [17] representing the distribution of the maxillary nerve (MX), mandibular nerve (MN), area of intersection of the glossopharyngeal and maxillary nerves (MX-GLO), and glossopharyngeal nerve only (GLO) were touched to check the positive GR (GSI III grade) response. 20 patients with a positive GR reflex in 1 or more of the evaluated areas were included in the second step of the study. Patients who had different GSI grades in different areas were excluded. Areas with a positive GR (GSI grade III) were considered as ‘1’ and areas with a negative GR were considered as ‘0’ for statistical analysis of mapping (fig. 1b). After mapping the positive GR areas, the earplugs were inserted bilaterally similar to the study group in step 1, and the patients were asked to wait in the patients’ room for 10 min. At the end of this period, the patients were reevaluated for GR positivity (GPI grade II–V considered as ‘1’) or negativity (GPI grade I considered as ‘0’) by touching the same areas in order to evaluate the absolute effectivity of the earplug technique for each area. Statistical Analysis The results of the first step of the study were statistically evaluated by using the Wilcoxon signed-rank test. The results of the second step of the study were statistically evaluated by using the McNemar tests with SPSS version 19.0 (SPSS Inc., Chicago, Ill, USA) and GraphPad software Prism 5.0 (San Diego, CA, USA).

Cakmak/Ozdogmus/Günay/Gürbüzer/Tezula¸s/ Kaspar/Hacıoglu

Downloaded by: NYU Medical Center Library 128.122.253.212 - 5/16/2015 12:23:07 PM

The prospective observational, non-randomized, clinical trial study was planned in 2 steps: In the first step of the study, 90 patients who had a GR during the maxillary irreversible hydrocolloid impression procedure (Kromopan, Firenze, Italy) were allocated to a study group (n = 30, 9 female, 21 male, mean: 35.2 ± 16.18) a sham group (n = 30, 14 female, 16 male, mean: 31.13 ± 10.94), and a control group (n = 30, 12 female, 18 male, mean: 30.6 ± 14.72). Irreversible hydrocolloid impression material was mixed in accordance with the instructions of the manufacturer, and impressions were taken by the same dentist. As a second step, the oral areas affected by the earplug were mapped in only those patients who had a GR of grade GSI III (moderate, consistent and limited treatment options) during maxillary irreversible hydrocolloid impression procedure (n = 20, 9 female, 11 male, mean: 46.3 ± 14.52).

Results

Step 2: Mapping the Effective Areas In the second step of the study, areas were mapped in which earplug application altered the GR, and the statistical significance of the results was evaluated. The positive GR responses in the MX area dissappeared with the earplug application and the results were statistically significant (p = 0.000). The positive GR response in the MX-GLO area, which includes the uvula, were also altered by the earplug technique; the results were also statistically significant (p = 0.008). The GRs triggered in the MN area, which contributes the lingual branch of mandibular division of the trigeminal nerve, were also altered clinically by the earplug application, and the effect was statistically significant (p = 0.000). On the other hand, for the GLO area (the posterior oropharyngeal wall) there was no significant difference between pre and post earplug application (p = 0.125). The analysis of step 2 is shown in figure 2.

Discussion Our results show that using earplugs is an effective technique to reduce GR triggered in the hard palate (MX area), uvula (MX-GLO area) and tongue (MN area), but not in posterior oropharyngeal wall (GLO). In addition, GR could not be reduced in either the sham or the control group. The maxillary irreversible hydrocolloid impression procedure mainly triggers GR through contact with trigeminal nerve areas (MX, MN, and MX-GLO), which are sufficiently blocked by the earplug, thus GR can be overcome in patients undergoing maxillary teeth impression procedures. The pre and post evaluations of the first step demonstrated clearly the effectiveness of the earplug technique when making impressions of the maxillary teeth.

Earplug Technique to Reduce Gag Reflex

Fig. 2. Graphical representation of the results; ns = not significant, * =  0.05, *** =  0.0005.

The skin of the EAC, that is stimulated by the earplug, receives auricular branches (Arnold’s branch) of the vagus nerve which is the efferent pathway of the GR. Arnold’s branch of the vagus arises from the superior (jugular) ganglion of the vagus and can receive fibers from the facial and glossopharyngeal nerves as well as the vagus nerve [18]. Moreover, Arnold’s branch receives input from all parts of the EAC but mostly from the posteroinferior wall [19, 20]. It might be speculated that supression of the GR with the earplug occurs by means of the contribution of Arnold’s branch to GLO; however the GR that is triggered from the posterior wall of the oropharynx could not be blocked by the earplug technique. Therefore the GR supression with the earplug application cannot be attributed to Arnold’s branch contribution to GLO. In addition, it has also been demonstrated that the stimulation of Arnold’s branch represents the motor functions of the vagus nerve (Arnold’s ear-cough reflex can be elicited by palpation of the EAC skin [18]); this might suggest that the GR motor pathway of the vagus nerve may be altered by earplug application. However, this effect may also be excluded on the basis of the intact GR from the posterior pharyngeal wall. On the other hand, it is worth mentioning that the sensory input from Arnold’s branch to the skin of the EAC also terminates at the trigeminal spinal nucleus although it travels with the vagus nerve and, moreover, the mandibular division of the trigeminal nerve gives off the auriculotemporal nerve which receives sensory input from walls of the EAC [7, 11, 12, 19–22]. Therefore, it can be speculated that earplug application may have a blocking effect for the GR mediated by the trigeminal nerve through auriculotemporal nerve and Arnold’s branch going to spinal nucleus of the trigeminal nerve and acting by compression of the walls of the EAC. The effect of the trigeminal contribution may also explain the GR suppression in addition to the intact GR from the posterior pharyngeal wall. The ophtalmic branch

Forsch Komplementmed 2014;21:94–98

97

Downloaded by: NYU Medical Center Library 128.122.253.212 - 5/16/2015 12:23:07 PM

Step 1: Efficacy The statistical analyses for the first step of the study showed that the GSI and GPI differences of the earplug group were statistically significant (p  0.0001). The GSI and GPI scores of 27 of the 30 patients showed a suppression of the GR in the earplug group. The GSI and GPI scores were equal in only 3 of the patients in the earplug group. In contrast, the GSI and GPI differences between control (p = 0.424) and sham group (p = 0.586) were not statistically significant. The GSI and GPI scores differed in 9 of 30 patients (4 of whom were increased) of the sham group. The GSI and GPI scores differed in only 4 (1 of whom was an increase) of 30 patients of the control group. However, the GSI and GPI scores were exactly equal in 26 of 30 patients of the control group in step 1 of the study. The analysis of step 1 results is shown in figure 2.

of the trigeminal nerve does not have any known corresponding areas within the oral cavity. In addition, no possible interactions in the brainstem to modulate the GR could be observed, that might have occured in the sham group in which the ophtalmic branch of the trigeminal nerve was stimulated with the aid of the forehead compression with stick-on metal spherical pellets. We can conclude that the GR blocking effects of the earplug application probably may have occurred due to the merging of the oropharyngeal trigeminal areas and EAC skin territories innervated by the trigeminal nerve. However, the details of the overlapping level could not be clarified in the present study and it is still needed to be investigated within the neuronal level with imaging techniques in humans. Furthermore, the earplug technique may also have a sedative effect in addition to its trigeminal blocking effects. It has been demonstrated that electrical stimulation of the ear skin areas innervated by Arnold’s branch has mood-enhancing effects [23]. Although such an additional benefit has not been evaluated in this study, we cannot exclude such a contribution as an add-on effect of GR modulation, in addition to trigeminal nerve contributions. Mood-enhancing effects of the earplug technique are needed to be clarified in further studies. Finally, further double blind and randomized studies are needed to replicate our results. The earplug technique may be effective not only in making impression of the maxillary teeth but also in other dental procedures, such as making a periapical radiograph of the poste-

rior teeth or retraction of the tongue. The technique is simple and noninvasive and may therefore also be helpful for pediatric oral examinations. However, the earplug technique may not be effective in every patient, as shown in the 3 cases in the first step of the study. Nevertheless, the earplug technique can be considered as an effective noninvasive option to alleviate GR before invasive techniques are applied.

Conclusion Patients with GR are a challenge to the dentist and we believe that the earplug technique, which is an easily applicable and noninvasive technique, can be accepted by all age groups and will be a step forward to overcome GR. Further, the effects of the earplug technique need to be investigated for other possible medical applications. In this study, we have described the earplug technique for the first time in literature and demonstrated that it can reduce GR in areas innervated from the trigeminal nerve during impression procedures of the maxillary teeth.

Disclosure Statement The authors of this manuscript declare that they have no conflict of interests.

References

98

10 Campbell WW: DeJong’s the Neurologic Examination. Philadelphia, Lippincott Williams & Wilkins, 2005. 11 Wazen JJ: Referred otalgia. Otolaryngol Clin North Am 1989;22:1205–1215. 12 Levine HL: Otorhinolaryngologic causes of headache. Med Clin N Am 1991;75:677–692. 13 Nihashi T, Kakigi R, Okada T, Sadato N, Kashikura K, Kajita Y, Yoshida J: Functional magnetic resonance imaging evidence for a representation of the ear in human primary somatosensory cortex: comparison with magnetoencephalography study. Neuroimage 2002;17:1217–1226. 14 Jegoux F, Legent F, Beauvillain de Montreuil C: Chronic cough and ear wax. Lancet 2002;360:618. 15 Shu J, Liu RY, Huang XF: Efficacy of ear-point stimulation on experimentally induced seizure. Acupunct Electrother Res 2005;30:43–52. 16 Dickinson C, Fiske J: A review of gagging problems in dentistry: I. Aetiology and classification. Dent Update 2005;32:31–32. 17 Berkovitz BKB, Holland GR, Moxham BJ: Oral Anatomy, Histology and Embryology. Amsterdam, Mosby-Elsevier, 2009.

Forsch Komplementmed 2014;21:94–98

18 Standring S: Gray’s Anatomy. Spain, Elsevier, 2008. 19 Tekdemir I, Aslan A, Elhan A: A clinico-anatomic study of the auricular branch of the vagus nerve and Arnold’s ear-cough reflex. Surg Radiol Anat 1998; 20:253–257. 20 Folan-Curran J, Cooke FJ: Contribution of cranial nerve ganglia to innervation of the walls of the rat external acoustic meatus. J Peripher Nerv Syst 2001; 6:28–32. 21 Gülekon N, Anil A, Poyraz A, Peker T, Turgut HB, Karaköse M: Variations in the anatomy of the auriculotemporal nerve. Clin Anat 2005;18:15–22. 22 Komarnitki I, Andrzejczak-Sobociƒska A, Tomczyk J, Deszczyƒska K, Ciszek B: Clinical anatomy of the auriculotemporal nerve in the area of the infratemporal fossa. Folia Morphol (Warsz) 2012;71: 187–193. 23 Kraus T, Hösl K, Kiess O, Schanze A, Kornhuber J, Forster C: BOLD fMRI deactivation of limbic and temporal brain structures and mood enhancing effect by transcutaneous vagus nerve stimulation. J Neural Transm 2007;114:1485–1493.

Cakmak/Ozdogmus/Günay/Gürbüzer/Tezula¸s/ Kaspar/Hacıoglu

Downloaded by: NYU Medical Center Library 128.122.253.212 - 5/16/2015 12:23:07 PM

1 Rosted P, Bundgaard M, Fiske J, Pedersen AM: The use of acupuncture in controlling the gag reflex in patients requiring an upper alginate impression: an audit. Br Dent J 2006;201:721–725. 2 Miles TS, Nauntofte B, Svensson P: Clinical Oral Physiology. Copenhagen, Quintessence Publishing Co. Ltd., 2004. 3 Fiske J, Dickinson C: The role of acupuncture in controlling the gagging reflex using a review of ten cases. Br Dent J 2001;190:611–613. 4 Scarborough D, Van-Kuren MB, Hughes M: Altering the gag reflex via a palm pressure point. J Am Dent Assoc 2008;139:1365–1372. 5 Saliba DL, McCutchen TA, Laxton MJ, Miller SA, Reynolds JE: Reliable block of the gag reflex in one minute or less. J Clin Anesth 2009;21:463. 6 Weissman JL: A pain in the ear: the radiology of otalgia. AJNR Am J Neuroradiol 1997;18:1641– 1651. 7 Jackler RK, Brackmann DE: Textbook of Neurotology. New York, Mosby Yearbook, 1994. 8 Kreisberg MK, Turner J: Dental causes of referred otalgia. Ear Nose Throat J 1987;166:30–48. 9 Bassi GS, Humphris GM, Longman LP: The etiology and management of gagging: a review of the literature. J Prosthet Dent 2004;91:459–467.

An earplug technique to reduce the gag reflex during dental procedures.

The gag reflex is a frequent problem occurring during dental treatment procedures, especially while making impressions of the maxillary teeth. The pre...
223KB Sizes 3 Downloads 3 Views