Do CBCT scans alter surgical treatment plans? Comparison of preoperative surgical diagnosis using panoramic versus cone-beam CT images

Abstract

Cone beam CT and/or panoramic images are often required for a successful diagnosis in oral and maxillofacial surgery. The aim of this study was to evaluate if 3D diagnostic imaging information had a significant impact on the decision process in six different classes of surgical indications.

Material and methods

Records of all patients who had undergone both panoramic X-ray and CBCT imaging due to surgical indications between January 2008 and December 2012 were examined retrospectively. In February 2013, all surgically relevant diagnoses of both conventional panoramic radiographs and CBCT scans were retrieved from the patient's charts. It was recorded whether (1) 3D imaging presented additional surgically relevant information and (2) if the final decision of surgical therapy had been based on 2D or 3D imaging.

Results

A total of 253 consecutive patients with both panoramic radiographs and CBCT analysis were eligible for the study. 3D imaging provided significantly more surgically relevant information in cases of implant dentistry, maxillary sinus diagnosis and in oral and maxillofacial traumatology. However, surgical strategies had not been influenced to any significant extent by 3D imaging.

Conclusion

Within the limitations of this study it may be concluded that CBCT imaging results in significantly more surgically relevant information in implant dentistry, maxillary sinus diagnosis and in cases of oral and maxillofacial trauma. However, 3D imaging information did not alter significantly the surgical plan that was based on 2D panoramic radiography. Further studies are necessary to define indications for CBCT in detail.

Introduction

Recent literature has suggested that panoramic and intraoral radiographic views are still the most practical basic imaging methods in dentistry, allowing the two dimensional (2D) viewing of oral hard tissues (Suomalainen et al., 2015). Panoramic radiographs can include in a single image the maxilla, mandible, teeth, temporomandibular joints and maxillary sinuses. During exposure, the X-ray source and detector rotate synchronously around the patient producing a curved surface tomography. However, due to the tomographic nature of the technique, only structures located within the tomographic plane are well delineated and those in front or behind that plane are blurred (Lurie, 2004), which may result in limited diagnostic information.

To overcome these shortcomings, cone beam CT (CBCT) devices were introduced in dento-maxillofacial imaging in the late 1990s (Arai et al., 1999, Mozzo et al., 1998). During X-ray exposure, a series of planar projection images of the field of view (FOV) are generated. When the basis projection images have been acquired, the CBCT unit reconstructs the primary projection frames to provide standard viewing displays of coronal, sagittal and axial images similar to the MSCT data display (Scarfe and Farman, 2008). At present, there is an ongoing discussion relating to the clinical indications of the 2D vs. the 3D technique.

In dental implantology, 2D imaging is adequate for a safe implant placement if it includes the relevant anatomical boundaries with adequate bone height and space (Harris et al., 2012). The information about bone width can be obtained from the clinical assessment. However, additional information in the third dimension may be of value in specific cases. In preoperative diagnosis and planning based on two-dimensional (2D) imaging, dental implants may be placed in areas with a potential risk of damage to vital structures. Thus, restricting preoperative diagnosis to 2D images in dental implant practice can potentially cause implant failures (Guerrero et al., 2014). Moreover, it was stated that three-dimensional evaluation of the sinus with CBCT was significantly more reliable in detecting pathology than panoramic imaging (Tadinada et al., 2015).

To enhance clarity in the discussion, evidence-based guidelines for the use of CBCT in dental and maxillofacial radiology were prepared by several institutions such as the European Commission guidelines (European Commission, 2012). However, there is little information whether 3D diagnosis results in alteration of surgical treatment plans based on 2D imaging. It was shown recently that CBCT imaging of suspected mandibular fractures resulted in a change in the treatment plan in 9.5% (Kaeppler et al., 2013). At present, it is unclear if similar percentages may be found when 2D information is compared to 3D diagnosis in other surgical indications.

Therefore, the aim of the present study was to evaluate if (1) 3D imaging resulted in significantly more surgically relevant information and if (2) 3D diagnostic imaging information had a significant impact on the decision process of the clinician working with the images, according to level three of the efficacy of new medical imaging techniques (i.e., diagnostic thinking efficacy), in six clinical indication groups (Fryback and Thornbury, 1991).