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A Rare Case of Nasolacrimal Duct Partial Obstruction After Extraction of an Impacted Maxillary Canine
Journal Pre-proof A rare case of nasolacrimal duct partial obstruction following extraction of an impacted maxillary canine Guoxu Han, MM, Resident, Ci Song, MM, Resident, Shaoqin Lin, Specialist Degree, Nurse, Zhengguo piao PII:
S0278-2391(19)31248-0
DOI:
https://doi.org/10.1016/j.joms.2019.10.020
Reference:
YJOMS 58955
To appear in:
Journal of Oral and Maxillofacial Surgery
Received Date: 4 August 2019 Revised Date:
22 October 2019
Accepted Date: 23 October 2019
Please cite this article as: Han G, Song C, Lin S, piao Z, A rare case of nasolacrimal duct partial obstruction following extraction of an impacted maxillary canine Journal of Oral and Maxillofacial Surgery (2019), doi: https://doi.org/10.1016/j.joms.2019.10.020. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Inc on behalf of the American Association of Oral and Maxillofacial Surgeons
A rare case of nasolacrimal duct partial obstruction following extraction of an impacted maxillary canine Guoxu Han, Ci Song, Shaoqin Lin, Zhengguo piao Corresponding Author: Zhengguo Piao, MD, Department Head, Tel:139288059 11, E-mail: [email protected], Affiliation: Key Laboratory of Oral M edicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangz hou Medical University, Guangzhou 510140, China. Mailing address: No.39, H uangsha Avenue, Liwan District, Guangzhou, Guangdong, China. 510140 Guoxu Han, MM, Resident, Affiliation: Key Laboratory of Oral Medicine, Gua ngzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China. Ci Song, MM, Resident, Affiliation: Department of Stomatology, Nanfang Hos pital, Southern Medical University Shaoqin Lin, Specialist Degree, Nurse, Affiliation: Department of Ophthalmolo gy, Nanfang Hospital, Southern Medical University Guoxu Han and Ci Song are co-first authors
A rare case of nasolacrimal duct partial obstruction following extraction of an impacted maxillary canine Abstract The main complications of tooth extraction include jaw fracture, maxillary sinus damage, adjacent teeth damage, nerve damage, root fracture, infection, bleeding and swelling. Despite a theoretical possibility that tooth extraction could result in nasolacrimal duct obstruction, there remains no reported cases to date. In this study, a case was reported where nasolacrimal duct was partially obstructed following extraction of an impacted maxillary canine, causing paranasal discomfort and lower eyelid swelling. Introduction The complications of tooth extraction are manifested in jaw fracture, maxillary sinus damage, adjacent teeth damage, nerve damage, root fracture, infection, bleeding, swelling, etc. Nevertheless, nasolacrimal duct damage caused by tooth extraction has not previously been reported. The lacrimal drainage system is comprised of the upper and lower lacrimal puncta, lacrimal canaliculi, lacrimal sac and nasolacrimal duct (NLD). Nasolacrimal duct obstruction (NLDO) is the most common type of abnormalities occurring in the lacrimal drainage system. NLDO can be classified into congenital or acquired, with acquired NLDO further classified into primary or secondary and complete or partial. Primary acquired NLDO has an undefined etiology, while secondary acquired NLDO may result from infection, inflammation, neoplasm, trauma and mechanical cause. The major symptoms of NLDO are known to include epiphora, painful swelling of the inner canthus, mucopurulent discharge and acute or chronic dacryocystitis.
The opening of NLD is in the junction of anterior one-third and posterior two-thirds of inferior meatus. Anatomically, it is closely located near the root of maxillary canine. Hence, NLDO is commonly associated with the problems involving maxillary canine. At present, the relationship between impacted maxillary canine and NLDO has not yet attracted sufficient attention. However, there have been some reported cases concerning the obstruction of nasolacrimal duct caused by impacted maxillary canine[1] or dental cyst derived from impacted maxillary canine[2]. Herein, a rare case was reported where NLD was partially obstructed following extraction of an impacted maxillary canine. Case Report An 18-year-old female presented with a 1-year history of left paranasal discomfort and 1month history of left lower eyelid swelling. One year earlier, the patient had been seen at other hospital for extraction of an impacted maxillary canine (left). During the following year, she experienced intermittent discomfort at left paranasal region which aworsened over the second half year. One month ago, swelling developed at left lower eyelid especially the inner canthus. Besides this, the patient described frequent left eye fatigue and felt her left globe being elevated. So an otolaryngologist was visited. A CT scan of orbital and paranasal sinuses was performed for suspected maxillary sinusitis which was subsequently ruled out. Though, intravenous antibiotic administration of three days was prescribed for diagnostic treatment, but it failed to make any difference. There were no other positive signs and symptoms identified. Physical examination revealed subtle facial asymmetry. Swelling of left lower eyelid with the inner canthus region in particular was identified at the time when the patient gently closed her eyes. Facial coloration showed no abnormalities (Fig 1). Palpation of left paranasal region revealed slight pain. Upon palpation of the swollen left lower eyelid, there was no pain and no
secretions discharged from the lacrimal punctum or the opening of the NLD. The pre-operative cone beam computed tomography (CBCT) demonstrated that the root apex of impacted maxillary canine was located near the opening of the NLD (Fig 2). Nasolacrimal duct damage during extraction of the tooth was suspected. Therefore, a CT scan of orbital and paranasal sinuses was performed. The result indicated that the left NLD was narrowed in the sagittal plane except the axial plane and coronal plane (Fig 3). The deviation of nasal septum was also discovered but not paranasal sinusitis. Then lacrimal passage syringing was conducted aiming to clarify whether the NLD was narrowed. When the lacrimal passage syringing was performing, the flushing liquid regurgitation was observed and the patient felt mild pain in the left side but not right side (Fig 4). To further confirm the diagnosis of NLDO, radiography of the bilateral NLD was performed. Radiography showed the contrast agent flow irregularly narrowed superior to inferior and discontinued at the opening of the left NLD. However, the contrast agent can still flow into the pharyngeal cavity. For the right NLD, the contrast agent flow was found to be continuous and the width of the duct was found to be consistent (Fig 5). Upon additional ophthalmological examination of both eyes including visual acuity, pupillary response, extraocular motility and intraocular pressure, were found within normal range. Based on above results, the diagnosis of partial obstruction of the left NLD was made. An informed consent document was signed by the patient. A standard lacrimal duct probing and syringing performed under local anesthesia alleviated the symptoms. The patient remained symptom-free over a postoperative follow-up of six months. Discussion The maxillary canine is the second most frequently impacted tooth, closely following\ third molars. Aktan et al. reported the incidence of maxillary canine impaction in a Turkish
subpopulation was 1.74 percent[3], while Al-Zoubi et al. reported a 2.5 percent occurrence rate in Madinah, Saudi Arabia[4]. Among the children and adolescents in southern China, Sajnani et al. reported an occurrence of 2.1 percent[5]. Surgical removal is necessary for some cases of maxillary canine impaction. Not only diseases but also surgical treatment in the region of the nose and paranasal sinuses are known to cause multiple ophthalmological disorders due to its close proximity to the lacrimal system and orbit. This case indicated that the NLD can be damaged during extraction of impacted maxillary canine. Generally, the NLD lies under the lateral wall of the nasal cavity and extends from the inner canthus to the inferior meatus, opening into the inferior meatus at the junction of its anterior onethird and posterior two-thirds. The opening is safeguarded by the lacrimal fold, or Hasner's valve. The duct lumen is usually straight and relatively symmetrical with the other side[6]. Embryologically, the bud of the maxillary canine is present from the gestational age of 4 months in utero and situated above the incisors, in the frontal process of the maxilla. The NLD is situated more superiorly, medially and posteriorly to the bud of maxillary canine. The bud of the maxillary canine descends physiologically at the age of 12[7]. When the maxillary canine is impacted especially when it moved to the superior, posterior or medial side, it will has a close proximity to the NLD, thus possibly causing NLD damage upon maxillary canine extraction. The causes of NLDO in this case possibly included narrowing of the NLD bone lumen, partial obstruction in the opening of the NLD and epithelial edema of the NLD. Narrowing of the NLD bone lumen was verified by the post-operative CT and the radiography. The pre-operative CBCT indicated the root of impacted maxillary canine was very close to the NLD. The bony wall of NLD can be displaced due to external force when elevating the root. The contrast agent was slowed at the opening of the NLD but could still flow into the pharyngeal cavity, which
illustrated it was only partial obstruction of the NLD. The soft tissue at the opening of the NLD may be damaged when removing the bone around the tooth by high-speed air turbine handpiece, which may lead to soft tissue hyperplasia and then causing the partial obstruction. The intermittent discomfort at paranasal region indicated the exist of chronic inflammation which may result in epithelial edema and inflammatory exudation of NLD, then causing the partial obstruction. There are several other stomatological causes of nasolacrimal duct obstruction including the impacted maxillary canine itself[8], periapical abscess of maxillary canines[9], infection at the fracture site of maxilla[10], odontogenic cysts[11] and orthognathic surgery[12]. In order to avoid nasolacrimal duct damage during extraction of an impacted maxillary canine, a set of guidelines were proposed to be followed prior to, during and following the procedure. Knowledge of the normal positional relationship between maxillary canine and NLD is necessary. A pre-operative CBCT can be performed to make a thorough evaluation of the positional relationship between the impacted maxillary canine and the NLD. During the operation, caution should be taken to avoid exerting force on the nasolacrimal duct and conserve its structural integrity when using elevator or high-speed air turbine handpiece. For postoperative care, rational administration of antibiotics can be applied to prevent the occurrence of infection. Once symptoms of NLDO begin to manifest itself, an ophthalmologist or otolaryngologist should be consulted promptly. In conclusion, our case highlights a previously unexplored relationship between tooth extraction and NLDO. As suggested by our findings, NLDO ought to be added to the long list of complications resulting from tooth extraction, and tooth extraction can be included among the secondary mechanical causes of NLDO.
Acknowledgement This study is supported by Guangzhou Municipal Health and Family Planning Commission (2017 14011327). References [1] Giordano RA, Bertazzoni G, Trimarchi M: Nasolacrimal Duct Obstruction Secondary to Dental Impaction. Eur J Ophthalmol 24:611, 2014 [2] Ray B, Bandyopadhyay SN, Das D, Adhikary B: A rare cause of nasolacrimal duct obstruction: dentigerous cyst in the maxillary sinus. Indian J Ophthalmol 57:465, 2009 [3] Aktan AM, Kara S, Akgünlü F, Malkoç S: The incidence of canine transmigration and tooth impaction in a Turkish subpopulation. Eur J Orthod 32:575, 2010 [4] Al-Zoubi H, Alharbi AA, Ferguson DJ, Zafar MS: Frequency of impacted teeth and categorization
of
impacted
canines:
A
retrospective
radiographic
study
using
orthopantomograms. Eur J Dent 11:117, 2017 [5] Sajnani AK, King NM: Prevalence and characteristics of impacted maxillary canines in southern Chinese children and adolescents. J Investig Clin Dent 5:38, 2013 [6] BD Chaurasia: Human Anatomy: Regional and Applied Dissection and Clinical. 5th Ed. St Prahlad, CBS, 2010, pp 65, 228 [7] Fayet B, Racy E, Bordonné C, Katowitz WR, Katowitz J, Brémond-Gignac D: Complex Bony Congenital Nasolacrimal Duct Obstruction Caused by an Adjacent Canine Tooth Bud. Ophthalmic Plast Reconstr Surg 35:e23, 2019 [8] Alexandrakis G, Hubbell RN, Aitken PA: Nasolacrimal duct obstruction secondary to ectopic teeth. Ophthalmology 107:189, 2000
[9] Anthony JM, Sandmeyer LS, Laycock AR: Nasolacrimal obstruction caused by root abscess of the upper canine in a cat. Vet Ophthalmol 13:106, 2010 [10] Odufuwa B, Rose GE: "Eye-tooth": a case of orbital dentigerous cyst after trauma. Arch Ophthalmol 119:1560, 2001 [11] Bajaj MS, Mahindrakar A, Pushker N: Dentigerous cyst in the maxillary sinus: a rare cause of nasolacrimal obstruction. Orbit 22:4, 2003 [12] Jang SY, Kim MK, Choi SM, Jang JW: Nasolacrimal duct obstruction after maxillary orthognathic surgery. J Oral Maxillofac Surg 71:1085, 2013 Fig. 1- Frontal view of one year post-operation. A: Eye open. B: Eye closed. Red arrow indicates the swelling of left lower eyelid. Fig. 2- Pre-operative CBCT of the left impacted maxillary canine. A: Axial plane. B: Coronal plane. C: Sagittal plane. Red arrows indicate the apex of the impacted canine. Fig. 3- A comparison of the nasolacrimal duct between pre-operative CBCT and post-operative CT. A: Coronal plane, pre-operative. B: Coronal plane, post-operative. C: Axial plane, preoperative. D: Axial plane, post-operative. E: Sagittal plane, pre-operative, right side. F: Sagittal plane, post-operative, right side. G: Sagittal plane, pre-operative, left side. H: Sagittal plane, post-operative, left side. Red arrows indicate the narrowing of left nasolacrimal duct. Fig. 4- Nasolacrimal duct syringing of the left eye. Red arrow indicates the regurgitation of normal saline solution. Fig. 5- Post-operative nasolacrimal duct radiography. A: Right side, the contrast agent was continuous and the width of NLD remained consistent. B: Left side, the contrast agent was discontinuous at the opening of NLD and the width of NLD irregularly narrowed superior to inferior.
S0278-2391(19)31248-0
DOI:
https://doi.org/10.1016/j.joms.2019.10.020
Reference:
YJOMS 58955
To appear in:
Journal of Oral and Maxillofacial Surgery
Received Date: 4 August 2019 Revised Date:
22 October 2019
Accepted Date: 23 October 2019
Please cite this article as: Han G, Song C, Lin S, piao Z, A rare case of nasolacrimal duct partial obstruction following extraction of an impacted maxillary canine Journal of Oral and Maxillofacial Surgery (2019), doi: https://doi.org/10.1016/j.joms.2019.10.020. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Inc on behalf of the American Association of Oral and Maxillofacial Surgeons
A rare case of nasolacrimal duct partial obstruction following extraction of an impacted maxillary canine Guoxu Han, Ci Song, Shaoqin Lin, Zhengguo piao Corresponding Author: Zhengguo Piao, MD, Department Head, Tel:139288059 11, E-mail: [email protected], Affiliation: Key Laboratory of Oral M edicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangz hou Medical University, Guangzhou 510140, China. Mailing address: No.39, H uangsha Avenue, Liwan District, Guangzhou, Guangdong, China. 510140 Guoxu Han, MM, Resident, Affiliation: Key Laboratory of Oral Medicine, Gua ngzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China. Ci Song, MM, Resident, Affiliation: Department of Stomatology, Nanfang Hos pital, Southern Medical University Shaoqin Lin, Specialist Degree, Nurse, Affiliation: Department of Ophthalmolo gy, Nanfang Hospital, Southern Medical University Guoxu Han and Ci Song are co-first authors
A rare case of nasolacrimal duct partial obstruction following extraction of an impacted maxillary canine Abstract The main complications of tooth extraction include jaw fracture, maxillary sinus damage, adjacent teeth damage, nerve damage, root fracture, infection, bleeding and swelling. Despite a theoretical possibility that tooth extraction could result in nasolacrimal duct obstruction, there remains no reported cases to date. In this study, a case was reported where nasolacrimal duct was partially obstructed following extraction of an impacted maxillary canine, causing paranasal discomfort and lower eyelid swelling. Introduction The complications of tooth extraction are manifested in jaw fracture, maxillary sinus damage, adjacent teeth damage, nerve damage, root fracture, infection, bleeding, swelling, etc. Nevertheless, nasolacrimal duct damage caused by tooth extraction has not previously been reported. The lacrimal drainage system is comprised of the upper and lower lacrimal puncta, lacrimal canaliculi, lacrimal sac and nasolacrimal duct (NLD). Nasolacrimal duct obstruction (NLDO) is the most common type of abnormalities occurring in the lacrimal drainage system. NLDO can be classified into congenital or acquired, with acquired NLDO further classified into primary or secondary and complete or partial. Primary acquired NLDO has an undefined etiology, while secondary acquired NLDO may result from infection, inflammation, neoplasm, trauma and mechanical cause. The major symptoms of NLDO are known to include epiphora, painful swelling of the inner canthus, mucopurulent discharge and acute or chronic dacryocystitis.
The opening of NLD is in the junction of anterior one-third and posterior two-thirds of inferior meatus. Anatomically, it is closely located near the root of maxillary canine. Hence, NLDO is commonly associated with the problems involving maxillary canine. At present, the relationship between impacted maxillary canine and NLDO has not yet attracted sufficient attention. However, there have been some reported cases concerning the obstruction of nasolacrimal duct caused by impacted maxillary canine[1] or dental cyst derived from impacted maxillary canine[2]. Herein, a rare case was reported where NLD was partially obstructed following extraction of an impacted maxillary canine. Case Report An 18-year-old female presented with a 1-year history of left paranasal discomfort and 1month history of left lower eyelid swelling. One year earlier, the patient had been seen at other hospital for extraction of an impacted maxillary canine (left). During the following year, she experienced intermittent discomfort at left paranasal region which aworsened over the second half year. One month ago, swelling developed at left lower eyelid especially the inner canthus. Besides this, the patient described frequent left eye fatigue and felt her left globe being elevated. So an otolaryngologist was visited. A CT scan of orbital and paranasal sinuses was performed for suspected maxillary sinusitis which was subsequently ruled out. Though, intravenous antibiotic administration of three days was prescribed for diagnostic treatment, but it failed to make any difference. There were no other positive signs and symptoms identified. Physical examination revealed subtle facial asymmetry. Swelling of left lower eyelid with the inner canthus region in particular was identified at the time when the patient gently closed her eyes. Facial coloration showed no abnormalities (Fig 1). Palpation of left paranasal region revealed slight pain. Upon palpation of the swollen left lower eyelid, there was no pain and no
secretions discharged from the lacrimal punctum or the opening of the NLD. The pre-operative cone beam computed tomography (CBCT) demonstrated that the root apex of impacted maxillary canine was located near the opening of the NLD (Fig 2). Nasolacrimal duct damage during extraction of the tooth was suspected. Therefore, a CT scan of orbital and paranasal sinuses was performed. The result indicated that the left NLD was narrowed in the sagittal plane except the axial plane and coronal plane (Fig 3). The deviation of nasal septum was also discovered but not paranasal sinusitis. Then lacrimal passage syringing was conducted aiming to clarify whether the NLD was narrowed. When the lacrimal passage syringing was performing, the flushing liquid regurgitation was observed and the patient felt mild pain in the left side but not right side (Fig 4). To further confirm the diagnosis of NLDO, radiography of the bilateral NLD was performed. Radiography showed the contrast agent flow irregularly narrowed superior to inferior and discontinued at the opening of the left NLD. However, the contrast agent can still flow into the pharyngeal cavity. For the right NLD, the contrast agent flow was found to be continuous and the width of the duct was found to be consistent (Fig 5). Upon additional ophthalmological examination of both eyes including visual acuity, pupillary response, extraocular motility and intraocular pressure, were found within normal range. Based on above results, the diagnosis of partial obstruction of the left NLD was made. An informed consent document was signed by the patient. A standard lacrimal duct probing and syringing performed under local anesthesia alleviated the symptoms. The patient remained symptom-free over a postoperative follow-up of six months. Discussion The maxillary canine is the second most frequently impacted tooth, closely following\ third molars. Aktan et al. reported the incidence of maxillary canine impaction in a Turkish
subpopulation was 1.74 percent[3], while Al-Zoubi et al. reported a 2.5 percent occurrence rate in Madinah, Saudi Arabia[4]. Among the children and adolescents in southern China, Sajnani et al. reported an occurrence of 2.1 percent[5]. Surgical removal is necessary for some cases of maxillary canine impaction. Not only diseases but also surgical treatment in the region of the nose and paranasal sinuses are known to cause multiple ophthalmological disorders due to its close proximity to the lacrimal system and orbit. This case indicated that the NLD can be damaged during extraction of impacted maxillary canine. Generally, the NLD lies under the lateral wall of the nasal cavity and extends from the inner canthus to the inferior meatus, opening into the inferior meatus at the junction of its anterior onethird and posterior two-thirds. The opening is safeguarded by the lacrimal fold, or Hasner's valve. The duct lumen is usually straight and relatively symmetrical with the other side[6]. Embryologically, the bud of the maxillary canine is present from the gestational age of 4 months in utero and situated above the incisors, in the frontal process of the maxilla. The NLD is situated more superiorly, medially and posteriorly to the bud of maxillary canine. The bud of the maxillary canine descends physiologically at the age of 12[7]. When the maxillary canine is impacted especially when it moved to the superior, posterior or medial side, it will has a close proximity to the NLD, thus possibly causing NLD damage upon maxillary canine extraction. The causes of NLDO in this case possibly included narrowing of the NLD bone lumen, partial obstruction in the opening of the NLD and epithelial edema of the NLD. Narrowing of the NLD bone lumen was verified by the post-operative CT and the radiography. The pre-operative CBCT indicated the root of impacted maxillary canine was very close to the NLD. The bony wall of NLD can be displaced due to external force when elevating the root. The contrast agent was slowed at the opening of the NLD but could still flow into the pharyngeal cavity, which
illustrated it was only partial obstruction of the NLD. The soft tissue at the opening of the NLD may be damaged when removing the bone around the tooth by high-speed air turbine handpiece, which may lead to soft tissue hyperplasia and then causing the partial obstruction. The intermittent discomfort at paranasal region indicated the exist of chronic inflammation which may result in epithelial edema and inflammatory exudation of NLD, then causing the partial obstruction. There are several other stomatological causes of nasolacrimal duct obstruction including the impacted maxillary canine itself[8], periapical abscess of maxillary canines[9], infection at the fracture site of maxilla[10], odontogenic cysts[11] and orthognathic surgery[12]. In order to avoid nasolacrimal duct damage during extraction of an impacted maxillary canine, a set of guidelines were proposed to be followed prior to, during and following the procedure. Knowledge of the normal positional relationship between maxillary canine and NLD is necessary. A pre-operative CBCT can be performed to make a thorough evaluation of the positional relationship between the impacted maxillary canine and the NLD. During the operation, caution should be taken to avoid exerting force on the nasolacrimal duct and conserve its structural integrity when using elevator or high-speed air turbine handpiece. For postoperative care, rational administration of antibiotics can be applied to prevent the occurrence of infection. Once symptoms of NLDO begin to manifest itself, an ophthalmologist or otolaryngologist should be consulted promptly. In conclusion, our case highlights a previously unexplored relationship between tooth extraction and NLDO. As suggested by our findings, NLDO ought to be added to the long list of complications resulting from tooth extraction, and tooth extraction can be included among the secondary mechanical causes of NLDO.
Acknowledgement This study is supported by Guangzhou Municipal Health and Family Planning Commission (2017 14011327). References [1] Giordano RA, Bertazzoni G, Trimarchi M: Nasolacrimal Duct Obstruction Secondary to Dental Impaction. Eur J Ophthalmol 24:611, 2014 [2] Ray B, Bandyopadhyay SN, Das D, Adhikary B: A rare cause of nasolacrimal duct obstruction: dentigerous cyst in the maxillary sinus. Indian J Ophthalmol 57:465, 2009 [3] Aktan AM, Kara S, Akgünlü F, Malkoç S: The incidence of canine transmigration and tooth impaction in a Turkish subpopulation. Eur J Orthod 32:575, 2010 [4] Al-Zoubi H, Alharbi AA, Ferguson DJ, Zafar MS: Frequency of impacted teeth and categorization
of
impacted
canines:
A
retrospective
radiographic
study
using
orthopantomograms. Eur J Dent 11:117, 2017 [5] Sajnani AK, King NM: Prevalence and characteristics of impacted maxillary canines in southern Chinese children and adolescents. J Investig Clin Dent 5:38, 2013 [6] BD Chaurasia: Human Anatomy: Regional and Applied Dissection and Clinical. 5th Ed. St Prahlad, CBS, 2010, pp 65, 228 [7] Fayet B, Racy E, Bordonné C, Katowitz WR, Katowitz J, Brémond-Gignac D: Complex Bony Congenital Nasolacrimal Duct Obstruction Caused by an Adjacent Canine Tooth Bud. Ophthalmic Plast Reconstr Surg 35:e23, 2019 [8] Alexandrakis G, Hubbell RN, Aitken PA: Nasolacrimal duct obstruction secondary to ectopic teeth. Ophthalmology 107:189, 2000
[9] Anthony JM, Sandmeyer LS, Laycock AR: Nasolacrimal obstruction caused by root abscess of the upper canine in a cat. Vet Ophthalmol 13:106, 2010 [10] Odufuwa B, Rose GE: "Eye-tooth": a case of orbital dentigerous cyst after trauma. Arch Ophthalmol 119:1560, 2001 [11] Bajaj MS, Mahindrakar A, Pushker N: Dentigerous cyst in the maxillary sinus: a rare cause of nasolacrimal obstruction. Orbit 22:4, 2003 [12] Jang SY, Kim MK, Choi SM, Jang JW: Nasolacrimal duct obstruction after maxillary orthognathic surgery. J Oral Maxillofac Surg 71:1085, 2013 Fig. 1- Frontal view of one year post-operation. A: Eye open. B: Eye closed. Red arrow indicates the swelling of left lower eyelid. Fig. 2- Pre-operative CBCT of the left impacted maxillary canine. A: Axial plane. B: Coronal plane. C: Sagittal plane. Red arrows indicate the apex of the impacted canine. Fig. 3- A comparison of the nasolacrimal duct between pre-operative CBCT and post-operative CT. A: Coronal plane, pre-operative. B: Coronal plane, post-operative. C: Axial plane, preoperative. D: Axial plane, post-operative. E: Sagittal plane, pre-operative, right side. F: Sagittal plane, post-operative, right side. G: Sagittal plane, pre-operative, left side. H: Sagittal plane, post-operative, left side. Red arrows indicate the narrowing of left nasolacrimal duct. Fig. 4- Nasolacrimal duct syringing of the left eye. Red arrow indicates the regurgitation of normal saline solution. Fig. 5- Post-operative nasolacrimal duct radiography. A: Right side, the contrast agent was continuous and the width of NLD remained consistent. B: Left side, the contrast agent was discontinuous at the opening of NLD and the width of NLD irregularly narrowed superior to inferior.