Marginal bone loss and resorption of second molars related to maxillary third molars in panoramic images compared with CBCT

Abstract

Objectives: Compare findings among observers in panoramic images (PAN) and cone beam CT (CBCT); and assess findings in PAN as indicators for marginal bone loss and resorption observed in CBCT. Methods: 120 impacted maxillary third molars with PAN and CBCT were included. Four observers assessed morphological features: (1) tooth angulation; (2) number of roots; (3) bony impaction (yes/no) and pathology; (4) marginal bone level at the second molar (normal/>3 mm = bone loss); (5) resorption in the second molar (no/superficial/< half way through the dentin/≥ half way through the dentin/involving the pulp); (6) size of follicular space (normal/> 4 mm(cyst)). Percentage accordance and κ statistics described observer variation in PAN and CBCT. Logistic regression analyses tested findings in PAN as indicators for marginal bone loss or resorption observed in CBCT. Results: κ values were fair and interobserver accordance was marginally higher in CBCT than PAN. Agreement between PAN and CBCT was 81-88% for marginal bone loss and 68-81% for resorption. Severe resorption was more often observed in CBCT. Mesio-angulated third molars and marginal bone loss interpreted in PAN significantly indicated marginal bone loss observed in CBCT (odds ration 17-34; p < 0.012; 8.8-52.8; p < 0.02). In contrast, findings in PAN were not significant indicators for resorption observed in CBCT (p > 0.05). conclusion: In general, there was a fair agreement for marginal bone loss between PAN and CBCT, and PAN could significantly predict bone loss observed in CBCT. However, presence of resorption observed in CBCT could not be determined from PAN, and more severe resorption was observed in CBCT. CBCT is indicated if resorption in the second molar needs to be assessed.

Risk factors for external root resorption of maxillary second molars due to impacted third molars as evaluated using cone beam computed tomography

“…In studies using peri-apical radiographs, MxM2 was associated with ERR in 11% of the cases 26 , and in studies using panoramic imaging, this was 8% 33 and 0.3% 34 . Thus, ERR in MxM2 is clearly underdiagnosed using 2D imaging, and the superiority of CBCT scans over panoramic imaging for the diagnosis of ERR has been shown in the literature 11,14 .…”

“…Therefore, based on the examination and clinical experience, the clinician will decide whether adjunctive CBCT imaging may provide further important information. Information about the localization and severity of ERR based on CBCT scans should facilitate the decision-making process, with options being conservative treatment of MxM2, prophylactic removal of MxM3, or removal of MxM2 instead of MxM3 11,14 . An irreversible pathology, such as severe ERR on MxM2 related to MxM3, is an indication for removal of MxM3 and sometimes MxM2 as well 6 or instead 14 .…”

“…Panoramic imaging is an accepted and readily available radiographic method for assessing M3 in both jaws 9,10 . However, the prevalence and severity of ERR on the adjacent second molars (M2) is more frequently observed using three-dimensional (3D) imaging modalities, such as cone beam computed tomography (CBCT) [11][12][13][14] . CBCT has already proven superior to two-dimensional (2D) radiography for the detection of ERR of the neighbouring teeth in studies related to impacted canines [15][16][17] and mandibular M3/M2 11 .…”

“…CBCT has already proven superior to two-dimensional (2D) radiography for the detection of ERR of the neighbouring teeth in studies related to impacted canines [15][16][17] and mandibular M3/M2 11 . However, only a few studies have analysed the predictors and prevalence of ERR on the distal surface of the maxillary M2 (MxM2) 11,13,14,[18][19][20] . Prevalence rates of 6.4% (n = 5) to 32.6% (n = 60) for ERR on MxM2 have been reported, usually with ERR being much less frequent in the maxilla than in the mandible, with ratios of 1:2.3 11 and 1:4 13 reported.…”

Impact of CBCT on treatment decision related to surgical removal of impacted maxillary third molars: does CBCT change the surgical approach?

“…A previous study has shown that panoramic imaging was not able to predict ERR when compared to a three-dimensional radiographic method, cone beam CT (CBCT), while panoramic imaging was to some extent able to predict marginal bone loss. 2 Nonetheless, CBCT exposes the patient to a higher radiation dose and involves higher costs for the patient and society than panoramic imaging, 3,4 and for that reason it is important only to perform a CBCT examination on evidence-based indications. While many studies are available on the impact of CBCT in assessing mandibular third molars prior to removal, [5][6][7][8] very few studies exist in the literature on maxillary third molars.…”