The Journal of Indian Prosthodontic Society

REVIEW ARTICLE
Year
: 2005  |  Volume : 5  |  Issue : 1  |  Page : 10--14

Imaging in implantology


S Bhat, S Shetty, KK Shenoy 
 Department of Prosthodontics, Yenepoya Dental College and Hospital, Mangalore, India

Correspondence Address:
S Bhat
Department of Prosthodontics, Yenepoya Dental College and Hospital, Mangalore
India

Abstract

Success in implant placement largely depends on presurgical evaluation and treatment planning. One can use a number of tools for this purpose. Imaging is an irreplaceable part of this armentarium. Today both film and filmless imaging techniques are used. This article highlights the evolution of various implant-imaging modalities from plain film radiography to the present 3D imaging.



How to cite this article:
Bhat S, Shetty S, Shenoy K K. Imaging in implantology.J Indian Prosthodont Soc 2005;5:10-14


How to cite this URL:
Bhat S, Shetty S, Shenoy K K. Imaging in implantology. J Indian Prosthodont Soc [serial online] 2005 [cited 2021 Jan 18 ];5:10-14
Available from: https://www.j-ips.org/text.asp?2005/5/1/10/16334


Full Text

The success of any surgical implant procedure depends on careful selection and preparation of the patient. Imaging is an irrefutable part of preoperative implant assessment to determine feasibility of fixture installment. It is one of the most accurate means by which the clinician can assess the morphologic features of the proposed fixture site, select implant of appropriate size and evaluate the fixture periodically after its placement.

The assessment includes

appraisal of proposed implant site,

determination of bone quantity and quality,

assessing inclination of alveolar process,

location of adjacent anatomic structures,

detect existing pathology. [1],[2],[3]

This paper gives a brief insight into the various imaging modalities, which have been applied in implantology.

 Plain film radiography



It is still the most widely used modality for pre and postoperative implant assessment. Both periapical [Figure 1] and occlusal radiographs [Figure 2] are known to provide the best image details with minimal geometric distortion of all the available modalities.[1],[4] They can resolve more than 20 pairs of lines per millimeter which is twice the resolving power of extraoral radiograph.

 Periapical radiograph



Features

Provide detailed information regarding the dimensions in length and height of available bone in small sections.

They are indicated for single tooth replacement.

Disadvantages

It is difficult to locate the inferior alveolar canal in the first molar region.

Correct positioning of film is difficult in edentulous region.

They do not give information regarding the bucco-lingual dimension.

This modality is limited by its 2D nature.

 Occlusal radiograph



Features

Usually used in conjunction with the periapical radiographs.

They show the buccolingual width between the extremes of buccal and lingual cortical plates.

Disadvantages

It fails to show the medial and lateral extent of cortical bone delineating the alveolar process as it displays only the extremes of the cortical plate.

This modality is limited by its 2D nature.

 Panoramic radiograph



They display image slices through the jaws by producing a single image of the maxilla and mandible and their supporting structures in a frontal plane [Figure 3].

Features

They display anatomic structures like nasal cavity, maxillary sinus, inferior alveolar canal and mental foramen.

Indicated when multiple implant placements are planned.

Disadvantages

The resolution is lesser when compared to intraoral radiograph.

A 10-20% image magnification occurs, which is nonuniform. This magnification is undesirable for both implant selection and implant site assessments.

Geometric distortion and overlapping of images of teeth can occur.

Overlapping of anterior region by vertebral column occurs.[5]

 Cephalometric radiograph



It displays an image of the skull and facial bones in the mid-saggital plane [Figure 4].

Features

It provides more accurately the information on inclination, height and width of alveolar bone at the midline, when compared to panoramic radiographs.[1]

It provides information regarding the relationship of the jaws when image is taken with teeth in occlusion.

Position and relationship of mental foramen, nasal fossa and maxillary sinus to the adjacent structures can be assessed.

Disadvantages

A 6-15% image magnification occurs which is undesirable as it leads to measurement errors of implant site.

Image resolution is less when compared to intraoral radiographs.[2]

 Conventional tomography



Conventional film-based tomography is designed to obtain clear images of structures lying within a plane of interest.

Features

It has been successfully applied to dental implant diagnostics for accurate assessment of alveolar bone height, width and inclination.

It can assess both the quality and the quantity of bone.

It gives information regarding the spatial relationship of vital structures.

Disadvantages

Insufficient contrast when compared to intraoral radiographs.

It is an expensive modality.

An expert radiologist is needed to interpret the image.[3]

 Digital radiography



It was first introduced in 1987 and became popular very soon. In this modality, the conventional film has been replaced by a 'charged couple device' (CCD).

Features

It allows rapid acquisition of images.

Postacquisition enhancement is possible.

Ease of storage, retrieval and transmission of images to remote site from the database.[1],[6]

Disadvantages

Digital radiography lacks the resolution of film radiography.

It has a much smaller active image area (17 26 mm) when compared to IOPA film (32 41 mm).

There are very few studies on the use of this technique for presurgical site evaluation.

 Computed tomography



Considering the new age tool, it blends the concept of thin layer radiography (tomography) with computer synthesis of image.[7] It was first applied successfully in implantology in the 1980s. In computed tomography (CT), multiple thin axial slices at small distances are obtained through the jaws and data is reformatted with special software package to produce cross-sectional, panoramic and 3D images [Figure 5].

Features

The CT always images entire arch, and normally is not used for single tooth replacements.

It can determine bone density in any region of the jaw.

The 3D image helps in accurately locating the vital structures.

Operator has an access to full range of contrasts.

It automatically calculates bone height and width in a specified region.

The information provided is a life size image, which is highly desirable for ease of measurements.[2],[5],[7],[8]

Disadvantages

It is an expensive modality.

An expert radiologist required to interpret the image.

Highradiation dosage when compared to conventional radiographic technique.

Patient's head position must remain constant throughout the entire imaging process of about 15-20 min.

 Recent advances in computed tomography



Cone beam CT is a relatively newer modality. It uses a conical beam and reconstructs the image in any direction using special software. It gives all the information of a CT but, at 1/8th the radiation dose and at a lower cost 9.

Microtomograph , another modification of CT is especially useful in acquiring serial sections of bone-implant interface.[9]

Multislice helical CT offers higher accuracy of images when compared to CT.[10]

 Tuned aperture computed tomography



It's a new and promising imaging modality, which is based on the principles of digital tomosynthesis.[11] The tuned aperture computed tomography (TACT) can selectively examine small segments without exposing entire axial plane[12] [Figure 6].

Features

It can isolate images of desired structures limited to certain depths.

It has the ability to accommodate patients' motion between exposures (unlike CT).

Flexibility to adjust contrast and resolution.[5],[6],[8]

Disadvantages

Information available about this modality is limited and restricted to very few studies.

It's application to implantology is still in research phase.

 Magnetic resonance imaging



Magnetic resonance imaging (MRI) is based on the phenomenon of nuclear magnetic resonance (NMR). First described in 1946, its application in implantology is however of recent origin.[13]

Features

The MRI can sharply delineate soft and hard tissues.

It can differentiate between cortical and cancellous bones.

The biggest advantage of MRI is 'zero radiation dose.'

Flexibility of plane acquisition.

Gives good soft tissue details.

Low level of imaging artifacts.

Disadvantages

It is an expensive tool.

At present no special software is available for specific use in implantology.

An expert radiologist is required to interpret the image.

The MRI application in implantology is still in its experimental phase.[2]

 Conclusion



Today's clinician has a wide array of diagnostic tools at his disposal. The CT gives the best information of the available modalities.[14] More commonly though a combination of intraoral periapical radiograph and a panoramic radiograph is used. To date no modality has been deemed perfect. So, the clinician has to carefully weight the pros and cons of each modality. The future for further development of imaging techniques specific for application in implantology is bright. We can definitely expect much more accurate, faster and safer modalities at lower cost to come into the field soon.

References

1Frederiksen NL. Diagnostic imaging in dental implantology: Oral Surgery Oral Medicine Oral Pathology 1995;80:540-54.
2Potter BJ, Shrout MK. Implant site assessment using cross-sectional tomographic image: Oral Surgery Oral Medicine Oral Pathology 1997;84:436-41.
3Kassebaum DK, McDowell JD. Tomography: DCNA 1993;37:567-74.
4Miles DA, Van ML. Implant radiology: DCNA 1993;37:645-65.
5Reiskin AB. Implant imaging: DCNA 1998;42:47-56.
6Vandre RH, Webber RL. Future trends in dental radiology: Oral Surgery Oral Medicine Oral Pathology 1995;80:471-8.
7Brooks SL. Computed tomography: DCNA 1993;37:575-90.
8Webber RL, Horton RA. Comparison of film, direct digital and TACT images to identify the location of crestal defects around endosseous titanium implants: Oral Surgery Oral Medicine Oral Pathology 1996;81:480-90.
9Sennerby L, Wennerberg A. A new microtomographic technique for non-invasive evaluation of the bone structure around Implants: Clin Oral Implants Res 2001;12:91.
10Naitoh M, Katsumata A. Measurement accuracy of reconstructed 2-D images obtained by multi-slice helical computed tomography: Clin Oral Implants Res 2004;15:570.
11Rashedi B, DMD, Tyndall DA. Tuned aperture computed tomography for cross-sectional implant site assessment in the posterior mandible: J Prosthodont 2003;12:176.
12Ito K, Gomi Y. Clinical application of a new compact CT system to assess 3-D images for the preoperative treatment planning of implants in the posterior mandible: Clin Oral Implants Res 2001;12:539.
13Mallya SM, Potluri A. Diagnostic imaging for implants: JIAOMR 2004;16:174-80.
14Fortin T, Champleboux G. Precision of transfer of preoperative planning for oral implants based on cone-beam CT-scan images through a robotic drilling machine: Clin Oral Implants Res 2002;13:6.