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| Title |
CBCT Modestly Improves Detection and Assessment of Distal Second-Molar Alveolar Bone Loss Compared with Panoramic Radiography in Patients with Impacted Third Molars |
| Clinical Question |
In patients with impacted third molars, does CBCT imaging compared with panoramic radiography provide greater accuracy in detecting and assessing adjacent second molar alveolar bone loss? |
| Clinical Bottom Line |
Compared to panoramic radiography, CBCT imaging can detect a higher prevalence of bone loss adjacent to impacted third molars, corresponding with higher accuracy. However, panoramic radiography is sufficient as an initial diagnostic tool. CBCT’s higher cost, radiation dose, and other barriers to widespread availability are limiting factors. CBCT should be reserved for cases where the assessment of bone loss on panoramic images is insufficient and more diagnostic information is necessary to inform treatment decisions. |
| Best Evidence |
(you may view more info by clicking on the PubMed ID link) |
| PubMed ID |
Author / Year |
Patient Group |
Study type
(level of evidence) |
| #1) 34520245 | Moreira-Souza/2022 | 503 third molars in 2 included studies on MBL | Systematic review of non-randomized trials | | Key results | One study reported an increased prevalence range of marginal bone loss on the CBCT (21.6% to 74%) versus the panoramic imaging (21.9 to 55.6%). Another study similarly reported a higher prevalence of marginal bone loss on the CBCT (80%) than the panoramic (62.9%). The prevalence of marginal bone loss was considered moderately higher on the CBCT than on the panoramic due to the superior visualization of 3-D structure on the CBCT, as reading of the panoramic image usually underestimates the severity of bone loss. The agreement between imaging modalities for marginal bone loss was between 66% and 85%. | | #2) 30652501 | Hermann/2019 | 93 patients with 120 impacted maxillary third molars | Retrospective Comparative Study | | Key results | Marginal bone loss at the distal surface of the second molars was observed in 81.6% of panoramic radiographs and 84.9% of CBCT scans, with 81-88% agreement between modalities. Bone loss seen on panoramic radiographs significantly predicted bone loss confirmed on CBCT (odds ratio 9-53, P< 0.02). Observer agreement for marginal bone loss was high, with 87% in panoramic images and 90% in CBCT (k = 0.65). | |
| Evidence Search |
(Impacted third molar OR impacted wisdom tooth) AND bone loss
CBCT AND Second Molar Bone Loss AND Panoramic
|
Comments on
The Evidence |
Hermann retrospectively evaluated 93 patients referred for CBCT after suspicion of pathology on panoramic radiographs. Both panoramic and CBCT were assessed by calibrated observers, and logistic regression analysis was used. Agreement between the modalities for marginal bone loss was substantial, but referral bias may have limited the generalizability of the results. Referral bias occurs when study participants may not be representative of the general population because of how they were selected. Moreira-Souza systematically reviewed the literature using PRISMA and PROSPERO. The two studies reporting on marginal bone loss both had a low risk of bias. Four studies had low risk of bias and one moderate. This study determined that CBCT is more accurate in assessment, but not necessarily required in most cases. |
| Applicability |
Both studies included patients with impacted third molars adjacent to second molars, a common finding in clinical practice. Their findings suggest that panoramic radiography is generally sufficient for detecting distal second molar bone loss. While CBCT may reveal more extensive bone loss, the increased accuracy in imaging does not necessarily modify the treatment plan or ultimate outcome. Ultimately, the use of the CBCT over the panoramic imaging modality would only be preferred in certain scenarios where it would inform future treatment. |
| Specialty/Discipline |
(Oral Medicine/Pathology/Radiology) |
| Keywords |
CBCT, Panoramic, Second Molar, Bone Loss
|
| ID# |
3593 |
| Date of submission: |
10/24/2025 |
| E-mail |
rubiny@livemail.uthscsa.edu |
| Author |
Yaron Rubin |
| Co-author(s) |
Amy Nguyen |
| Co-author(s) e-mail |
nguyena25@livemail.uthscsa.edu |
| Faculty mentor/Co-author |
Hassem Geha |
| Faculty mentor/Co-author e-mail |
geha@livemail.uthscsa.edu |
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?) |
post a rationale |
| None available | |
|
Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs) |
post a comment |
| None available | |
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