Q U I N T E S S E N C E I N T E R N AT I O N A L
OROFACIAL PAIN
Renzo Bassetti
The patent nasopalatine duct: A potential cause of unclear pain in the anterior maxilla Renzo Bassetti, DMD, MAS, Dr med dent 1/Peter Werder, DMD, MAS, Dr med dent2/Manuel Crameri, DMD, Dr med dent2/Anderas Ebinger, DMD, Dr med dent3/Alexandra Stähli, DMD, Dr med dent4/Regina Mericske-Stern, DMD, Prof Dr med dent 5/Johannes Kuttenberger, MD, DMD, PhD, Dr med, Dr med dent6 Objective: The aim of this report is to describe symptoms that can suggest the presence of a patent nasopalatine duct and to illustrate three cases. Summary: Patent nasopalatine ducts connecting the oral cavity with the nasal cavity are extremely rare. This malformation can be considered a developmental abnormality. Clinically, patent nasopalatine ducts appear as single or double spherical or oval apertures lateral or posterior to the incisive papilla. This type of anatomical malformation can be associated with an unclear pain sensation in the anteri-
or maxillary region, which may be misinterpreted for example as toothache of endodontic origin. However, persisting nasopalatine ducts can also exist as an asymptomatic abnormality with no clinical sign of discomfort. Accordingly, understanding the differential diagnosis of a possible patent nasopalatine duct can prevent a general practitioner from performing unnecessary interventions, such as endodontic treatments, apical surgeries, or tooth extractions. (Quintessence Int 2015;46:73–79; doi: 10.3290/j.qi.a32815)
Key words: incisive papilla, misdiagnosis, nasopalatine duct, vomeronasal organ
The nasopalatine duct (NPD) is a viable, epitheliumlined oronasal communication found in most mammals. It links the oral cavity to the nasal cavity, running from the incisive papilla to the nasal cavity.1-3 In mammals the NPD has been shown to transmit pheromones
1
Lecturer, Department of Prosthodontics, University of Bern, Switzerland; and Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland.
2
Lecturer, Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland.
3
Lecturer, Department of Prosthodontics, University of Bern, Switzerland.
4
Lecturer, Department of Periodontology, University of Bern, Switzerland.
5
Professor in Chair, Department of Prosthodontics, University of Bern, Switzerland.
6
Chairman, Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland.
Correspondence: Dr med dent Renzo Bassetti, Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, 6000 Lucerne, Switzerland. Email: [email protected]
VOLUME 46 • NUMBER 1 • JANUARY 2015
and chemosignals entering the oral cavity to the vomeronasal organ (VNO), also called “Jacobson’s organ”.1,2 The VNO consists of sensory cells that may play roles in tracking prey, sex recognition, and courtship displays.2,4 In humans, the NPD is found as an intact canal only during the fetal period. During early prenatal development phases, the paired inherent NPD runs within the same mesenchymal tissue as the nasopalatine nerve (NPN). In later development phases, a bony septum evolves on each side between the NPN and NPD, which separates them near the nasal cavity.5 Thus, the incisive canal and the NPD must be considered two different anatomical structures.6 The NPD almost always degenerates before birth and only epithelial remnants survive.5,7-10 Examinations of the human VNO from the embryonic stage and throughout life show that VNOs do not degenerate prenatally during the fetal develop-
73
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nasopalatine nerve terminal branch of descending palatine artery
1
1
1
1
Stenson´s foramina
2
Scarpa´s foramina
2
1
1
2
2
1 nasal floor
palatal side 23% Fig 1
65%
9%
frequency
Schematic diagram of the morphology and anatomical variations of the nasopalatine canal according to Mraiwa et al.18
ment phase but rather seem to grow in length after birth.3,11 Consistently, in humans, the VNO is a discrete structure with no neural element, so it lacks chemosensory function.3,11,12 A few case reports suggest the presence of a patent NPD in adults,6,13-15 and several authors have discussed hereditary etiologies of the NPD.16 The existence of a patent NPD in humans was first described by Leboucq in 1881.17 However, in most reported cases no computed tomography (CT) had been performed and usually no information regarding follow-up for more than 1 or 2 weeks can be found. The incisive canal is a bony conduit that develops within the posterior area of the primary palate and allows the NPNs and concomitant blood vessels to pass from the nasal cavity to the mucosa of the anterior palate of the oral cavity.5 A study including 34 consecutive spiral CT scans of the maxilla performed to describe
74
3%
anatomical variations of the nasopalatine (incisive) canal revealed the following findings:18 On the palatal side only one opening appeared, whereas on the nasal side, one (cylinder-canal morphology) or two openings (Stenson’s foramina, Y-canal morphology) could be observed, through which the NPN and the terminal branch of the descending palatine artery pass. Rarely, in addition to the Stenson’s foramina, one or two openings (Scarpa’s foramina) exist, which entail the NPNs (Fig 1).18,19 In the present case series, two of the three patients with patent NPDs had maxillary pain. In contrast, no clinical symptom was present despite the persisting NPD in the third case. With maxillary pain or asymptomatic palatal openings in the maxillary anterior area, the general practitioner should keep in mind a patent NPD in the differential diagnosis to avoid unnecessary dental or oral surgical interventions.
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Table 1
Clinical symptoms/findings and the presence of patent NPD in the three cases presented
Clinical symptoms/findings related to the presence of the patent NPD
Fig 2 Occlusal view of anterior maxillary arch with one opening on the left posterior side of incisive papilla (arrow).
Fig 3 Gutta-percha point in the NPD showing no communication between the oral and nasal cavities (CBCT: sagittal section).
CASE REPORTS Case 1 A 65-year-old woman presenting with a pain sensation in the anterior maxilla was referred by her dentist. The patient had elevated blood pressure, rheumatoid arthritis of the finger joints, and a penicillin allergy. Two years earlier three implants had been inserted in her maxilla. All three implants were lost within a few months after loading (bar-retained maxillary removable overdenture). Thus, the maxilla was edentulous apart from an impacted and asymptomatic maxillary right canine. After healing of the maxillary tissues a complete denture had been installed. At 9 months after the complete denture mounting, the patient presented with sudden discomfort in the anterior palatal region, a bad taste, and secretions from the anterior palatal region. Clinical examination
VOLUME 46 • NUMBER 1 • JANUARY 2015
Applicable case
Discomfort in the anterior palatal region after complete denture mounting in the maxilla
1
Bad taste in the mouth
1
Secretions from the anterior palatal region
1
Persisting pain on mastication in the maxillary anterior area
2
Dull pain in the anterior hard palate region
2
Ability to produce squeaky noises performing low pressure in the anterior palate
3
Asymptomatic persisting fistula laterally of the incisive papilla
3
Fig 4 Gutta-percha point showing no communication between the translocated maxillary right canine and NPD (occlusal radiograph).
revealed a small mucosal opening on the left posterior side of the incisive papilla (Fig 2). Palpation of this area was painful and secretion of a serous fluid could be provoked (Table 1). A gutta-percha point was inserted into the opening and both an exploratory cone beam CT (CBCT) scan (Fig 3) and occlusal radiography (Fig 4) were performed. The radiographs revealed a partially patent NDP, which showed no relationship to the translocated maxillary right canine (Fig 4). The NPD was rinsed with a 0.12% chlorhexidine solution (Meridol Perio, GABA), and Ledermix paste (Riemser) was applied into the opening. At 1 week after therapy, the symptoms had resolved and the mucosa was inconspicuous. At 1 year after the procedure, the patient was free of symptoms.
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Fig 5 Radiographic situation after endodontic treatment of maxillary right central and lateral incisors (single radiograph using the parallel technique: anterior view).
Fig 6 Radiographic situation 6 months after apical surgery and open flap debridement (single radiograph using the parallel technique: anterior view).
Fig 7 Insertion of two gutta-percha points into the two openings of the NPDs.
Fig 8 Gutta-percha points in the two NPDs showing communication between the oral and nasal cavities (CBCT: axial, sagittal, and coronal sections).
Case 2 A 53-year-old woman was referred by her dentist with unclear persisting pain in the anterior maxillary region after endodontic treatment and apical surgery. Eighteen months previously, the patient suffered slight tooth trauma in the right maxillary anterior area (central and lateral incisor). Due to persistent pain in the anterior right maxilla in the region of the central and lateral incisor, especially during mastication, endodontic treatment was initiated at the maxillary right lateral incisor, and 2 months later at the central incisor (Fig 5). Despite apical surgery at the central incisor and an open flap debridement at the central and lateral incisor, the pain persisted (Fig 6). The patient complained of pain on mastication in the right maxillary anterior area and a dull pain in the anterior hard palate region (Table 1). Clinical examination revealed two small mucosal openings on either side of the incisive papilla, which could
76
Fig 9 Gutta-percha points showing no communication between the reossified hole apically of the maxillary right central incisor after apical surgery (single radiograph using the parallel technique: anterior view).
be probed partially (Fig 7). Palpation of this area was painful. Two gutta-percha points were inserted into the two openings and an exploratory CBCT scan (Fig 8) and single radiograph using the half-angle technique (Fig 9) were performed. The CBCT confirmed two patent NDPs with oronasal communication (Fig 8). Both NPDs were rinsed with a 0.1% chlorhexidine solution (formula hos-
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Case 3
Fig 10 Occlusal view of the maxillary arch presenting two small depressions of the mucosa on either side of the incisive papilla.
A 41-year-old man was referred by his dentist for diagnostic evaluation of a persisting fistula on the right side of the incisive papilla. The patient had not suffered from pain in this area previously, but mentioned an ability to produce squeaky noises when generating low pressure in the anterior palate (Table 1). Pulp sensitivity, using CO2 snow, was tested to exclude endodontic pathologies of the maxillary right canine to left canine. Clinical examination revealed two small depressions of the mucosa on either side of the incisive papilla, which could be probed without pain or bleeding (Fig 10). Two gutta-percha points were inserted into the two openings (Fig 11) and a CBCT scan was performed (Fig 12). The CBCT confirmed the existence of two patent NDPs with oronasal communication (Fig 12). Because of the asymptomatic situation, no therapy was performed and the patient was informed about his rare anatomical anomaly. At 6 months after diagnosis, the patient continued to be symptom-free.
DISCUSSION Fig 11 ings.
Insertion of two gutta-percha points into the two open-
Fig 12 Gutta-percha points in the two NPDs showing communication between the oral and nasal cavities (CBCT: axial, sagittal, and coronal sections).
pitalis; Hospital Pharmacy, Lucerne Cantonal Hospital) under local anesthesia (Ubistesin forte, 3M), and Ledermix paste (Riemser) was applied into both openings. Three weeks after therapy initiation the symptoms had resolved and a nonirritated mucosal situation could be seen. At 6 months after the procedure, the patient was free of symptoms.
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In this case series, the diagnosis of a patent NPD in adults presenting with maxillary pain or with asymptomatic palatal openings is illustrated. Moreover, the therapeutic option of rinsing in this context is suggested. Two patients, Cases 1 and 2, presented with symptoms of pain, whereas no pain was observed in Case 3 despite a persisting NPD. A patent NPD may be identified when it causes symptoms, or it may be diagnosed as an incidental finding. Consistently, about half of the cases in the literature were symptomatic.13 Thus, a patent NPD is rare, but it is important to consider it in the differential diagnosis of pain in the maxillary anterior region. However, given the rare occurrence of pathologies in the incisive papilla area, many dentists may not pay particular attention to this region.13 Moreover, the openings are mostly completely covered by the lateral portion of the incisive papilla and are thus not seen readily on inspection of the gingiva.16,20,21 Consequently, the anatomical variant of a patent NPD may
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easily be overlooked. Indeed, such patients often have a long history of vain consultations and treatments with doctors and dentists.22 Furthermore, it is unclear whether, compared with a closed NPD, cyst formation in the anterior maxillary region may occur more frequently, although it is believed that a nasopalatine cyst develops from epithelial remnants of the NPD.23-26 The following clinical symptoms may be indicative of a patent NPD: • debris collection, ability to produce squeaky noises27 (Case 3) • persistent drainage, discharge1,22 • passage of food or liquids into the nasal cavity13 • bad taste in the mouth1,22 (Case 1) • unclear pain or discomfort in the anterior maxilla (Case 1) • local swelling2,27 • influx of air from the oral cavity into the nasal cavity28 • soreness over the roof of the mouth1 • postoperative positive nose-blowing test6,14 • discomfort in the anterior palatal region after complete denture mounting in the maxilla (Case 1), and pain on mastication in the maxillary anterior area and a dull pain in the anterior hard palate region (Case 2). Given the rarity of a patent NPD, there are no standard treatment recommendations. Diverse procedures have been described previously, such as excision of the patent NPD after releasing a palatal full-thickness flap and subsequent coverage,1 and chemical ablation.13 However, to date there has been no controlled clinical study investigating or comparing different treatment options for a symptomatic patent NPD. Considering the limitations of the present case series, the therapeutic approach used in Cases 1 and 2 (irrigation with 0.1% to 0.12% chlorhexidine and application of Ledermix) is certainly not evidence based. The expectation was merely to reduce the inflammation; no attempt was made to correct the malformation. This procedure may provide a simple and feasible therapeutic approach, although symptoms may reoccur and evidence in the literature for success over time is lacking.
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Keeping a patent NPD in mind in the differential diagnosis is important to avoid unnecessary and potentially irreversible dental or surgical interventions, such as endodontic treatments, apical surgery, tooth extractions, or primary closures of an alleged oro-antral connection using a buccal or palatal soft-tissue flap in the presence of a positive nose-blowing test after tooth extraction.
ACKNOWLEDGMENTS The authors thank Bernadette Rawyler, who designed the schematic diagram of the morphology and anatomical variations of the nasopalatine canal.
REFERENCES 1. Chapple IL, Ord RA. Patent nasopalatine ducts: four case presentations and review of the literature. Oral Surg Oral Med Oral Pathol 1990;69:554–558. 2. Jacob S, Zelano B, Gungor A, Abbott D, Naclerio R, McClintock MK. Location and gross morphology of the nasopalatine duct in human adults. Arch Otolaryngol Head Neck Surg 2000;126:741–748. 3. Smith TD, Bhatnagar KP. The human vomeronasal organ. Part II: prenatal development. J Anat 2000;197(Pt 3):421–436. 4. Estes RD. The role of the vomeronasal organ in mammalian reproduction. Mammalia 1972;36:315–341. 5. Radlanski RJ, Emmerich S, Renz H. Prenatal morphogenesis of the human incisive canal. Anat Embryol (Berl) 2004;208:265–271. 6. Von Arx T, Bornstein MM. [The patent nasopalatine duct. A rare anomaly and diagnostic pitfall]. Schweiz Monatsschr Zahnmed 2009;119:379–389. 7. Abrams AM, Howell FV, Bullock WK. Nasopalatine cysts. Oral Surg Oral Med Oral Pathol 1963;16:306–332. 8. Bellairs AD. Observations on the incisive canaliculi and nasopalatine ducts. Br Dent J 1951;91:281–291. 9. Eppley BL, Delfino JJ. Bilateral nasopalatine ducts of the premaxilla. Int J Oral Maxillofac Surg 1988;17:360–362. 10. Noyes HJ. Nasopalatine duct and Jacobson’s organ in newborn infants. J Dent Res 1935;15:155–156. 11. Bhatnagar KP, Smith TD. The human vomeronasal organ. III. Postnatal development from infancy to the ninth decade. J Anat 2001;199:289–302. 12. Bhatnagar KP, Smith TD, Winstead W. The human vomeronasal organ: part IV. Incidence, topography, endoscopy, and ultrastructure of the nasopalatine recess, nasopalatine fossa, and vomeronasal organ. Am J Rhinol 2002;16: 343–350. 13. Lundner AS, Warunek SP. Patent nasopalatine ducts after rapid maxillary expansion. Am J Orthod Dentofacial Orthop 2006;130:96–99. 14. Valstar MH, van den Akker HP. Patent nasopalatine duct: a diagnostic pitfall. Br J Oral Maxillofac Surg 2008;46:304–305. 15. Ebinger A, Katsoulis J, Merickse-Stern R, Bassetti R. Der Ductus nasopalatinus. Quintessenz 2011;62:1335–1338. 16. Signy H, Rule DC. Palatal opening of a nasopalatine duct. Br Dent J 1982;153:371–372. 17. Leboucq H. Le canal nasopalatin chez l’homme. Arch Biol Paris 1881;2:386–397. 18. Mraiwa N, Jacobs R, Van Cleynenbreugel J, et al. The nasopalatine canal revisited using 2D and 3D CT imaging. Dentomaxillofac Radiol 2004;33:396–402.
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19. Jacobs R, Lambrichts I, Liang X, et al. Neurovascularization of the anterior jaw bones revisited using high-resolution magnetic resonance imaging. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;103:683–693. 20. Allard RH, de Vries K, van der Kwast WA. Persisting bilateral nasopalatine ducts: A developmental anomaly. Report of a case. Oral Surg Oral Med Oral Pathol 1982;53:24–26. 21. Blackburn CW. Patent nasopalatine ducts. Br Dent J 1984;157:401–402. 22. Catros S, De Gabory L, Stoll D, Deminiere C, Fricain JC. Use of gutta percha cores in CT scan imaging for patent nasopalatine duct. Int J Oral Maxillofac Surg 2008;37:1065–1066. 23. Anneroth G, Hall G, Stuge U. Nasopalatine duct cyst. Int J Oral Maxillofac Surg 1986;15:572–580.
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24. Gnanasekhar JD, Walvekar SV, al-Kandari AM, al-Duwairi Y. Misdiagnosis and mismanagement of a nasopalatine duct cyst and its corrective therapy. A case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1995;80:465–470. 25. Suter VG, Altermatt HJ, Voegelin TC, Bornstein MM. [The nasopalatine duct cyst: epidemiology, diagnosis and therapy]. Schweiz Monatsschr Zahnmed 2007;117:824–839. 26. Vasconcelos R, de Aguiar MF, Castro W, de Araujo VC, Mesquita R. Retrospective analysis of 31 cases of nasopalatine duct cyst. Oral Dis 1999;5:325–328. 27. Shimura Y, Nakamura A, Michi K. Palatal opening of the nasopalatine duct. A case report. Int J Oral Maxillofac Surg 1993;22:142–143. 28. Knecht M, Kittner T, Beleites T, Huttenbrink KB, Hummel T, Witt M. Morphological and radiologic evaluation of the human nasopalatine duct. Ann Otol Rhinol Laryngol 2005;114:229–232.
79
OROFACIAL PAIN
Renzo Bassetti
The patent nasopalatine duct: A potential cause of unclear pain in the anterior maxilla Renzo Bassetti, DMD, MAS, Dr med dent 1/Peter Werder, DMD, MAS, Dr med dent2/Manuel Crameri, DMD, Dr med dent2/Anderas Ebinger, DMD, Dr med dent3/Alexandra Stähli, DMD, Dr med dent4/Regina Mericske-Stern, DMD, Prof Dr med dent 5/Johannes Kuttenberger, MD, DMD, PhD, Dr med, Dr med dent6 Objective: The aim of this report is to describe symptoms that can suggest the presence of a patent nasopalatine duct and to illustrate three cases. Summary: Patent nasopalatine ducts connecting the oral cavity with the nasal cavity are extremely rare. This malformation can be considered a developmental abnormality. Clinically, patent nasopalatine ducts appear as single or double spherical or oval apertures lateral or posterior to the incisive papilla. This type of anatomical malformation can be associated with an unclear pain sensation in the anteri-
or maxillary region, which may be misinterpreted for example as toothache of endodontic origin. However, persisting nasopalatine ducts can also exist as an asymptomatic abnormality with no clinical sign of discomfort. Accordingly, understanding the differential diagnosis of a possible patent nasopalatine duct can prevent a general practitioner from performing unnecessary interventions, such as endodontic treatments, apical surgeries, or tooth extractions. (Quintessence Int 2015;46:73–79; doi: 10.3290/j.qi.a32815)
Key words: incisive papilla, misdiagnosis, nasopalatine duct, vomeronasal organ
The nasopalatine duct (NPD) is a viable, epitheliumlined oronasal communication found in most mammals. It links the oral cavity to the nasal cavity, running from the incisive papilla to the nasal cavity.1-3 In mammals the NPD has been shown to transmit pheromones
1
Lecturer, Department of Prosthodontics, University of Bern, Switzerland; and Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland.
2
Lecturer, Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland.
3
Lecturer, Department of Prosthodontics, University of Bern, Switzerland.
4
Lecturer, Department of Periodontology, University of Bern, Switzerland.
5
Professor in Chair, Department of Prosthodontics, University of Bern, Switzerland.
6
Chairman, Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland.
Correspondence: Dr med dent Renzo Bassetti, Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, 6000 Lucerne, Switzerland. Email: [email protected]
VOLUME 46 • NUMBER 1 • JANUARY 2015
and chemosignals entering the oral cavity to the vomeronasal organ (VNO), also called “Jacobson’s organ”.1,2 The VNO consists of sensory cells that may play roles in tracking prey, sex recognition, and courtship displays.2,4 In humans, the NPD is found as an intact canal only during the fetal period. During early prenatal development phases, the paired inherent NPD runs within the same mesenchymal tissue as the nasopalatine nerve (NPN). In later development phases, a bony septum evolves on each side between the NPN and NPD, which separates them near the nasal cavity.5 Thus, the incisive canal and the NPD must be considered two different anatomical structures.6 The NPD almost always degenerates before birth and only epithelial remnants survive.5,7-10 Examinations of the human VNO from the embryonic stage and throughout life show that VNOs do not degenerate prenatally during the fetal develop-
73
Q U I N T E S S E N C E I N T E R N AT I O N A L Bassetti et al
nasopalatine nerve terminal branch of descending palatine artery
1
1
1
1
Stenson´s foramina
2
Scarpa´s foramina
2
1
1
2
2
1 nasal floor
palatal side 23% Fig 1
65%
9%
frequency
Schematic diagram of the morphology and anatomical variations of the nasopalatine canal according to Mraiwa et al.18
ment phase but rather seem to grow in length after birth.3,11 Consistently, in humans, the VNO is a discrete structure with no neural element, so it lacks chemosensory function.3,11,12 A few case reports suggest the presence of a patent NPD in adults,6,13-15 and several authors have discussed hereditary etiologies of the NPD.16 The existence of a patent NPD in humans was first described by Leboucq in 1881.17 However, in most reported cases no computed tomography (CT) had been performed and usually no information regarding follow-up for more than 1 or 2 weeks can be found. The incisive canal is a bony conduit that develops within the posterior area of the primary palate and allows the NPNs and concomitant blood vessels to pass from the nasal cavity to the mucosa of the anterior palate of the oral cavity.5 A study including 34 consecutive spiral CT scans of the maxilla performed to describe
74
3%
anatomical variations of the nasopalatine (incisive) canal revealed the following findings:18 On the palatal side only one opening appeared, whereas on the nasal side, one (cylinder-canal morphology) or two openings (Stenson’s foramina, Y-canal morphology) could be observed, through which the NPN and the terminal branch of the descending palatine artery pass. Rarely, in addition to the Stenson’s foramina, one or two openings (Scarpa’s foramina) exist, which entail the NPNs (Fig 1).18,19 In the present case series, two of the three patients with patent NPDs had maxillary pain. In contrast, no clinical symptom was present despite the persisting NPD in the third case. With maxillary pain or asymptomatic palatal openings in the maxillary anterior area, the general practitioner should keep in mind a patent NPD in the differential diagnosis to avoid unnecessary dental or oral surgical interventions.
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Table 1
Clinical symptoms/findings and the presence of patent NPD in the three cases presented
Clinical symptoms/findings related to the presence of the patent NPD
Fig 2 Occlusal view of anterior maxillary arch with one opening on the left posterior side of incisive papilla (arrow).
Fig 3 Gutta-percha point in the NPD showing no communication between the oral and nasal cavities (CBCT: sagittal section).
CASE REPORTS Case 1 A 65-year-old woman presenting with a pain sensation in the anterior maxilla was referred by her dentist. The patient had elevated blood pressure, rheumatoid arthritis of the finger joints, and a penicillin allergy. Two years earlier three implants had been inserted in her maxilla. All three implants were lost within a few months after loading (bar-retained maxillary removable overdenture). Thus, the maxilla was edentulous apart from an impacted and asymptomatic maxillary right canine. After healing of the maxillary tissues a complete denture had been installed. At 9 months after the complete denture mounting, the patient presented with sudden discomfort in the anterior palatal region, a bad taste, and secretions from the anterior palatal region. Clinical examination
VOLUME 46 • NUMBER 1 • JANUARY 2015
Applicable case
Discomfort in the anterior palatal region after complete denture mounting in the maxilla
1
Bad taste in the mouth
1
Secretions from the anterior palatal region
1
Persisting pain on mastication in the maxillary anterior area
2
Dull pain in the anterior hard palate region
2
Ability to produce squeaky noises performing low pressure in the anterior palate
3
Asymptomatic persisting fistula laterally of the incisive papilla
3
Fig 4 Gutta-percha point showing no communication between the translocated maxillary right canine and NPD (occlusal radiograph).
revealed a small mucosal opening on the left posterior side of the incisive papilla (Fig 2). Palpation of this area was painful and secretion of a serous fluid could be provoked (Table 1). A gutta-percha point was inserted into the opening and both an exploratory cone beam CT (CBCT) scan (Fig 3) and occlusal radiography (Fig 4) were performed. The radiographs revealed a partially patent NDP, which showed no relationship to the translocated maxillary right canine (Fig 4). The NPD was rinsed with a 0.12% chlorhexidine solution (Meridol Perio, GABA), and Ledermix paste (Riemser) was applied into the opening. At 1 week after therapy, the symptoms had resolved and the mucosa was inconspicuous. At 1 year after the procedure, the patient was free of symptoms.
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Fig 5 Radiographic situation after endodontic treatment of maxillary right central and lateral incisors (single radiograph using the parallel technique: anterior view).
Fig 6 Radiographic situation 6 months after apical surgery and open flap debridement (single radiograph using the parallel technique: anterior view).
Fig 7 Insertion of two gutta-percha points into the two openings of the NPDs.
Fig 8 Gutta-percha points in the two NPDs showing communication between the oral and nasal cavities (CBCT: axial, sagittal, and coronal sections).
Case 2 A 53-year-old woman was referred by her dentist with unclear persisting pain in the anterior maxillary region after endodontic treatment and apical surgery. Eighteen months previously, the patient suffered slight tooth trauma in the right maxillary anterior area (central and lateral incisor). Due to persistent pain in the anterior right maxilla in the region of the central and lateral incisor, especially during mastication, endodontic treatment was initiated at the maxillary right lateral incisor, and 2 months later at the central incisor (Fig 5). Despite apical surgery at the central incisor and an open flap debridement at the central and lateral incisor, the pain persisted (Fig 6). The patient complained of pain on mastication in the right maxillary anterior area and a dull pain in the anterior hard palate region (Table 1). Clinical examination revealed two small mucosal openings on either side of the incisive papilla, which could
76
Fig 9 Gutta-percha points showing no communication between the reossified hole apically of the maxillary right central incisor after apical surgery (single radiograph using the parallel technique: anterior view).
be probed partially (Fig 7). Palpation of this area was painful. Two gutta-percha points were inserted into the two openings and an exploratory CBCT scan (Fig 8) and single radiograph using the half-angle technique (Fig 9) were performed. The CBCT confirmed two patent NDPs with oronasal communication (Fig 8). Both NPDs were rinsed with a 0.1% chlorhexidine solution (formula hos-
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Case 3
Fig 10 Occlusal view of the maxillary arch presenting two small depressions of the mucosa on either side of the incisive papilla.
A 41-year-old man was referred by his dentist for diagnostic evaluation of a persisting fistula on the right side of the incisive papilla. The patient had not suffered from pain in this area previously, but mentioned an ability to produce squeaky noises when generating low pressure in the anterior palate (Table 1). Pulp sensitivity, using CO2 snow, was tested to exclude endodontic pathologies of the maxillary right canine to left canine. Clinical examination revealed two small depressions of the mucosa on either side of the incisive papilla, which could be probed without pain or bleeding (Fig 10). Two gutta-percha points were inserted into the two openings (Fig 11) and a CBCT scan was performed (Fig 12). The CBCT confirmed the existence of two patent NDPs with oronasal communication (Fig 12). Because of the asymptomatic situation, no therapy was performed and the patient was informed about his rare anatomical anomaly. At 6 months after diagnosis, the patient continued to be symptom-free.
DISCUSSION Fig 11 ings.
Insertion of two gutta-percha points into the two open-
Fig 12 Gutta-percha points in the two NPDs showing communication between the oral and nasal cavities (CBCT: axial, sagittal, and coronal sections).
pitalis; Hospital Pharmacy, Lucerne Cantonal Hospital) under local anesthesia (Ubistesin forte, 3M), and Ledermix paste (Riemser) was applied into both openings. Three weeks after therapy initiation the symptoms had resolved and a nonirritated mucosal situation could be seen. At 6 months after the procedure, the patient was free of symptoms.
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In this case series, the diagnosis of a patent NPD in adults presenting with maxillary pain or with asymptomatic palatal openings is illustrated. Moreover, the therapeutic option of rinsing in this context is suggested. Two patients, Cases 1 and 2, presented with symptoms of pain, whereas no pain was observed in Case 3 despite a persisting NPD. A patent NPD may be identified when it causes symptoms, or it may be diagnosed as an incidental finding. Consistently, about half of the cases in the literature were symptomatic.13 Thus, a patent NPD is rare, but it is important to consider it in the differential diagnosis of pain in the maxillary anterior region. However, given the rare occurrence of pathologies in the incisive papilla area, many dentists may not pay particular attention to this region.13 Moreover, the openings are mostly completely covered by the lateral portion of the incisive papilla and are thus not seen readily on inspection of the gingiva.16,20,21 Consequently, the anatomical variant of a patent NPD may
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easily be overlooked. Indeed, such patients often have a long history of vain consultations and treatments with doctors and dentists.22 Furthermore, it is unclear whether, compared with a closed NPD, cyst formation in the anterior maxillary region may occur more frequently, although it is believed that a nasopalatine cyst develops from epithelial remnants of the NPD.23-26 The following clinical symptoms may be indicative of a patent NPD: • debris collection, ability to produce squeaky noises27 (Case 3) • persistent drainage, discharge1,22 • passage of food or liquids into the nasal cavity13 • bad taste in the mouth1,22 (Case 1) • unclear pain or discomfort in the anterior maxilla (Case 1) • local swelling2,27 • influx of air from the oral cavity into the nasal cavity28 • soreness over the roof of the mouth1 • postoperative positive nose-blowing test6,14 • discomfort in the anterior palatal region after complete denture mounting in the maxilla (Case 1), and pain on mastication in the maxillary anterior area and a dull pain in the anterior hard palate region (Case 2). Given the rarity of a patent NPD, there are no standard treatment recommendations. Diverse procedures have been described previously, such as excision of the patent NPD after releasing a palatal full-thickness flap and subsequent coverage,1 and chemical ablation.13 However, to date there has been no controlled clinical study investigating or comparing different treatment options for a symptomatic patent NPD. Considering the limitations of the present case series, the therapeutic approach used in Cases 1 and 2 (irrigation with 0.1% to 0.12% chlorhexidine and application of Ledermix) is certainly not evidence based. The expectation was merely to reduce the inflammation; no attempt was made to correct the malformation. This procedure may provide a simple and feasible therapeutic approach, although symptoms may reoccur and evidence in the literature for success over time is lacking.
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Keeping a patent NPD in mind in the differential diagnosis is important to avoid unnecessary and potentially irreversible dental or surgical interventions, such as endodontic treatments, apical surgery, tooth extractions, or primary closures of an alleged oro-antral connection using a buccal or palatal soft-tissue flap in the presence of a positive nose-blowing test after tooth extraction.
ACKNOWLEDGMENTS The authors thank Bernadette Rawyler, who designed the schematic diagram of the morphology and anatomical variations of the nasopalatine canal.
REFERENCES 1. Chapple IL, Ord RA. Patent nasopalatine ducts: four case presentations and review of the literature. Oral Surg Oral Med Oral Pathol 1990;69:554–558. 2. Jacob S, Zelano B, Gungor A, Abbott D, Naclerio R, McClintock MK. Location and gross morphology of the nasopalatine duct in human adults. Arch Otolaryngol Head Neck Surg 2000;126:741–748. 3. Smith TD, Bhatnagar KP. The human vomeronasal organ. Part II: prenatal development. J Anat 2000;197(Pt 3):421–436. 4. Estes RD. The role of the vomeronasal organ in mammalian reproduction. Mammalia 1972;36:315–341. 5. Radlanski RJ, Emmerich S, Renz H. Prenatal morphogenesis of the human incisive canal. Anat Embryol (Berl) 2004;208:265–271. 6. Von Arx T, Bornstein MM. [The patent nasopalatine duct. A rare anomaly and diagnostic pitfall]. Schweiz Monatsschr Zahnmed 2009;119:379–389. 7. Abrams AM, Howell FV, Bullock WK. Nasopalatine cysts. Oral Surg Oral Med Oral Pathol 1963;16:306–332. 8. Bellairs AD. Observations on the incisive canaliculi and nasopalatine ducts. Br Dent J 1951;91:281–291. 9. Eppley BL, Delfino JJ. Bilateral nasopalatine ducts of the premaxilla. Int J Oral Maxillofac Surg 1988;17:360–362. 10. Noyes HJ. Nasopalatine duct and Jacobson’s organ in newborn infants. J Dent Res 1935;15:155–156. 11. Bhatnagar KP, Smith TD. The human vomeronasal organ. III. Postnatal development from infancy to the ninth decade. J Anat 2001;199:289–302. 12. Bhatnagar KP, Smith TD, Winstead W. The human vomeronasal organ: part IV. Incidence, topography, endoscopy, and ultrastructure of the nasopalatine recess, nasopalatine fossa, and vomeronasal organ. Am J Rhinol 2002;16: 343–350. 13. Lundner AS, Warunek SP. Patent nasopalatine ducts after rapid maxillary expansion. Am J Orthod Dentofacial Orthop 2006;130:96–99. 14. Valstar MH, van den Akker HP. Patent nasopalatine duct: a diagnostic pitfall. Br J Oral Maxillofac Surg 2008;46:304–305. 15. Ebinger A, Katsoulis J, Merickse-Stern R, Bassetti R. Der Ductus nasopalatinus. Quintessenz 2011;62:1335–1338. 16. Signy H, Rule DC. Palatal opening of a nasopalatine duct. Br Dent J 1982;153:371–372. 17. Leboucq H. Le canal nasopalatin chez l’homme. Arch Biol Paris 1881;2:386–397. 18. Mraiwa N, Jacobs R, Van Cleynenbreugel J, et al. The nasopalatine canal revisited using 2D and 3D CT imaging. Dentomaxillofac Radiol 2004;33:396–402.
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19. Jacobs R, Lambrichts I, Liang X, et al. Neurovascularization of the anterior jaw bones revisited using high-resolution magnetic resonance imaging. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;103:683–693. 20. Allard RH, de Vries K, van der Kwast WA. Persisting bilateral nasopalatine ducts: A developmental anomaly. Report of a case. Oral Surg Oral Med Oral Pathol 1982;53:24–26. 21. Blackburn CW. Patent nasopalatine ducts. Br Dent J 1984;157:401–402. 22. Catros S, De Gabory L, Stoll D, Deminiere C, Fricain JC. Use of gutta percha cores in CT scan imaging for patent nasopalatine duct. Int J Oral Maxillofac Surg 2008;37:1065–1066. 23. Anneroth G, Hall G, Stuge U. Nasopalatine duct cyst. Int J Oral Maxillofac Surg 1986;15:572–580.
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24. Gnanasekhar JD, Walvekar SV, al-Kandari AM, al-Duwairi Y. Misdiagnosis and mismanagement of a nasopalatine duct cyst and its corrective therapy. A case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1995;80:465–470. 25. Suter VG, Altermatt HJ, Voegelin TC, Bornstein MM. [The nasopalatine duct cyst: epidemiology, diagnosis and therapy]. Schweiz Monatsschr Zahnmed 2007;117:824–839. 26. Vasconcelos R, de Aguiar MF, Castro W, de Araujo VC, Mesquita R. Retrospective analysis of 31 cases of nasopalatine duct cyst. Oral Dis 1999;5:325–328. 27. Shimura Y, Nakamura A, Michi K. Palatal opening of the nasopalatine duct. A case report. Int J Oral Maxillofac Surg 1993;22:142–143. 28. Knecht M, Kittner T, Beleites T, Huttenbrink KB, Hummel T, Witt M. Morphological and radiologic evaluation of the human nasopalatine duct. Ann Otol Rhinol Laryngol 2005;114:229–232.
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