|Year : 2016 | Volume
| Issue : 1 | Page : 36-40
Three-dimensional localisation of impacted teeth with cone-beam computed tomography: A case series
Sarabjeet Singh Sandhu1, Taruna Puri1, Rishabh Kapila2, Navreet Sandhu3
1 Department of Orthodontics and Dentofacial Orthopaedics, Bhojia Dental College and Hospital, Baddi, Himachal Pradesh, India
2 Department of Oral Medicine and Radiology, Bhojia Dental College and Hospital, Baddi, Himachal Pradesh, India
3 Department of Prosthodontics, Bhojia Dental College and Hospital, Baddi, Himachal Pradesh, India
|Date of Web Publication||16-Feb-2016|
E-33, GHS-94, Sector 20, Panchkula - 134 116, Haryana
Since its introduction into dentistry in 1998, cone-beam computed tomography (CBCT) has become an increasingly important source of three-dimensional volumetric data in clinical orthodontics. CBCT should be used only in specific cases in which conventional radiography cannot supply satisfactory diagnostic information; these include patients with cleft palate, assessment of position of unerupted tooth, supernumerary teeth, identification of root resorption, and for planning of orthognathic surgery. Two-dimensional diagnostic imaging, such as traditional radiographs, cephalometric tracings, photographs, and video imaging have been routinely used as orthodontic diagnostic records since many years. The limitations of these imaging modalities include geometric distortion, magnification, superimposition of structures, projective displacements, rotational errors, and linear projective transformation. These errors can be easily overcome by the CBCT. The purpose of this is to highlight the significance of CBCT in diagnosis and treatment planning in the orthodontics.
Keywords: Cone beam computed tomography, impacted tooth, three dimensional imaging
|How to cite this article:|
Sandhu SS, Puri T, Kapila R, Sandhu N. Three-dimensional localisation of impacted teeth with cone-beam computed tomography: A case series. SRM J Res Dent Sci 2016;7:36-40
|How to cite this URL:|
Sandhu SS, Puri T, Kapila R, Sandhu N. Three-dimensional localisation of impacted teeth with cone-beam computed tomography: A case series. SRM J Res Dent Sci [serial online] 2016 [cited 2020 Aug 13];7:36-40. Available from: http://www.srmjrds.in/text.asp?2016/7/1/36/176478
| Introduction|| |
An impacted tooth is a tooth which is completely or partially unerupted and is positioned against another tooth, bone or soft tissue so that its further eruption is unlikely.
The most commonly impacted teeth are in the following sequence, the mandibular third permanent molar, maxillary permanent canine, and occasionally the premolars. This impaction can be horizontal, vertical, mesioangular, distoangular or inverted of which inversion is very rare. Inversion is defined as “the malposition of a tooth in which the tooth has reversed and is positioned upside down”.
Although new diagnostic imaging techniques have been introduced in recent years, conventional two-dimensional (2D) radiographs, including panoramic, occlusal, and periapical radiographs remain the most commonly used modality for the primary diagnosis and localization of nonerupted teeth and treatment planning. However, 2D radiographic images are very limited in demonstrating the exact location of these teeth, the impact on neighboring teeth and other adjacent structures, and the anatomy of roots, which is of absolute relevance in treatment planning.
Computed tomography (CT) eliminates image superimposition and allows reconstruction of scanned structures in different planes, as well as three-dimensional (3D) reconstructions., Another recent and increasingly available modality in dentistry is cone-beam computed tomography (CBCT) which produces the high-quality diagnostic 3D images with minimal distortion has relatively low cost, and significantly reduced radiation dose as compared to other CT modalities. Due to its increasing availability, there has been a significant current interest of researchers and clinicians in revisiting different clinical conditions using CBCT, which has allowed significant advances in dental practice. In cases of impacted teeth, images obtained by CBCT are accurate in determining their buccal-palatal location and angulation; in determining the proximity of impacted teeth to the roots of adjacent teeth, as well as the degree of resorption., These features are important in treatment planning to move the impacted tooth in the arch and decrease the risk of root resorption of adjacent teeth. Various types of imaging software allow CBCT image reconstructions in multiple planes, providing a better view of the impacted tooth position.
In this paper, we present two cases of inverted and impacted teeth in which CBCT was done for their exact localization and an effective treatment planning.
| Case Series|| |
A 13-year-old female patient reported with a chief complaint of spacing in upper left side of teeth region. Extraoral examination revealed that she had a mesocephalic head and mesoprosopic facial form. Patient's face was apparently symmetrical with the convex facial profile. Lips were competent with an interlabial gap of 1-2 mm. On clinical examination, the maxilla was found to be protrusive with retrusive mandible [Figure 1]. On intraoral examination, a missing left maxillary canine was noted with an increased overjet of 4.5 mm, increased overbite of 71% and upper midline was shifted toward left by 2 mm [Figure 2]. The patient showed a positive visual treatment objective when she was asked to protrude her mandible [Figure 3].
The intraoral periapical radiographs, orthopantomogram, and lateral cephaogram showed an inverted and impacted left maxillary canine [Figure 4]a,[Figure 4]b,[Figure 4]c. The palatal position of impacted canine was confirmed by taking two intraoral periapical radiographs using the SLOB rule. To confirm the 3D position of the canine, the patient was advised for a CBCT.
|Figure 4: (a) Intraoral periapical radiographs. (b) Orthopantomogram. (c) Lateral cephalogram|
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CBCT confirmed that the maxillary left canine was inverted and impacted. A 3D reconstruction [Figure 5] confirmed the 3D position of canine. On frontal view, [Figure 6]a maxillary left canine appeared to be tilted mesiodistally with the crown more distally placed than the root. On the lateral view, the crown appeared to be tilted buccolingually with crown portion more buccally placed than the root portion [Figure 6]b. As seen in the axial view, the inverted canine appears to be 0.56 mm away from the maxillary sinus and 0.76 mm away from the nasal cavity [Figure 7]. The same findings were confirmed on the coronal view [Figure 8]. As the impacted inverted canine was in an unfavorable position and could not be orthodontically extruded, it was extracted surgically.
A 12-year-old male patient reported with a chief complaint of irregular front teeth. Extraoral examination revealed that he had a mesocephalic head and mesoprosopic facial form. Patient's face was apparently symmetrical with the convex facial profile. Lips were incompetent with an interlabial gap of 6 mm [Figure 9]. On intraoral examination, there was crowding in upper and lower arches, an overjet of 3 mm, overbite of 3 mm, and upper midline was shifted toward right by 2 mm [Figure 10].
The intraoral periapical radiographs and orthopantomogram showed an inverted and impacted mesiodens between the two maxillary central incisors. The mesiodens was located palatal to the central incisors as seen by taking two intraoral periapical radiographs using SLOB technique [Figure 11]a,[Figure 11]b,[Figure 11]c. A 3D CBCT was done which showed the inverted and impacted mesiodens. CBCT confirmed the diagnosis of inverted and impacted mesiodens. On 3D view, the mesiodens was present in relation to a radicular portion of 21 [Figure 12]a. On sagittal view, the inverted mesiodens showed complete crown formation with incomplete root formation [Figure 12]b. It was present in the apical one-third of a radicular portion of 21, on the palatal side causing thinning of the palatal cortical plate. As seen in the coronal view the inverted mesiodens appeared to be 4 mm away from the nasal cavity [Figure 12]c. The same findings were confirmed by the axial view and the coronal view [Figure 13]a and [Figure 13]b. As, the mesiodens was a supernumerary teeth and in an unfavorable position, it was extracted.
|Figure 11: (a) Intraoral periapical radiographs. (b) Orthopantomogram. (c) Lateral cephalogram|
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|Figure 12: (a) Three-dimensional view. (b) Sagittal view. (c) Coronal view|
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| Discussion|| |
CBCT has been shown to improve diagnosis and possibly contribute to modifications in treatment planning in case of impacted teeth. CBCT has been shown to enhance the ability to accurately localize the tooth, evaluate its proximity to other teeth, examine the follicle size and assess resorption of the adjacent teeth.
It has been shown in studies that CBCT provides more information than orthopantomograms for localizing impacted and retained teeth, root resorption, cleft lip and palate, and third molar evaluations. Root length, root form, and root resorption are routinely assessed via periapical radiographs. However, CBCT may provide enhanced visualization of roots, making it a valuable tool for assessing preorthodontic or postorthodontic root resorption. CBCT has been shown to be better than orthopantomograms in determining root angulations.,,
CBCT has a lower amount of radiation exposure, as compared to spiral CT. It has been shown in studies that radiation exposure by CBCT units is almost equivalent or slightly higher than traditional imaging.,
The advantages of CBCT over traditional imaging were clearly seen in the two reported cases where the exact localization of impacted and inverted teeth was made with CBCT, which helped in an effective treatment planning and management of these cases.
| Conclusion|| |
Therefore, a reliable assessment of the 3D position and improved localization and surgical-orthodontic management of impacted teeth can be done using CBCT.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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