Chairs:
ingrid rózylo-kalinowska
roberto molteni

84: HUMAN ANALOGUE STUDY ASSESSING POSSIBLE IMPACT OF CBCT ON OUTCOME EFFICACY IN ENDODONTIC ACCESS CAVITY PREPARATIONS

M.B. McGuigan1, H.F. Duncan2, J. Ludwig3, G. Krastl4, K. Horner5

1Dublin Dental University Hospital, Trinity College Dublin, Division of Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, Dublin, Ireland, 2Dublin Dental University Hospital, Trinity College Dublin, Division of Restorative Dentistry and Periodontology, Dublin, Ireland, 3University Hospital of Würzburg Germany, Dept of Endodontics, Würzburg, Germany, 4University Hospital of Würzburg, Department of Conservative Dentistry and Periodontology, Würzburg, Germany, 5The University of Manchester, Division of Oral and Maxillofacial Imaging, Manchester, United Kingdom

Aim: To identify if supplemental CBCT imaging could potentially improve outcome after endodontic access cavity preparation in a human analogue ‘with or without study’ using 3D-printed maxillary first molars (M1Ms).

Material\Methods: After pilot and sample size calculation, 18 operators with 3 experience-levels were randomised to two simulated clinical sessions. An 8-week washout period was implemented prior to session 2. Operators attempted location of all 4 root-canals in three custom-made M1Ms of differing anatomical complexity, consulting preoperative periapical radiographs +/- CBCT imaging. Primary outcome was tooth volume removed (ITK-SNAP-quantified) and secondary outcomes were linear cavity-dimensions, canals located, and procedural-time. Operator confidence and ‘helpfulness’ of both conventional/CBCT imaging on canal location was assessed using a five-point confidence scale rating.

Results: 108 access cavities were analysed. Supplemental CBCT-imaging significantly reduced tooth volume removed, procedural time (Paired t-tests, p<0.05) and increased mesiobuccal-2 (MB2) canal location (Fishers Exact test) for standard anatomies and more experienced operators. Linear mixed-effect modelling, identified image type and operator experience as significant with respect to tooth volume removed and procedural time (p<0.05), but not the study session (1st/2nd). There was significantly lower confidence in canal location and perceived ‘helpfulness” (all experience groups) with/of conventional imaging alone compared with additional CBCT imaging.

Conclusions: Within the limitations of this 3D-printed study, supplemental preoperative CBCT availability reduced tooth volume removed, procedural time and improved location of MB2 canals, with simpler anatomies and experienced operators. These findings could potentially impact on endodontic outcomes including fracture resistance, tooth survival and reduction of apical disease.

86: THE APPLICATION AND THE VALIDITY OF A NEW COMPOSITE RADIOGRAPHIC INDEX IN PATIENTS WITH OSTEONECROSIS OF THE JAWS

Z. Yfanti1, S. Tetradis2, N.G. Nikitakis3, K.E. Alexiou1, E. Vardas3, C. Angelopoulos1, K. Tsiklakis1

1National and Kapodistrian University of Athens, School of Dentistry, Department of Oral Diagnosis and Radiology, Athens, Greece, 2UCLA School of Dentistry, Section of Oral Maxillofacial Radiology, Los Angeles, CA, United States, 3National and Kapodistrian University of Athens, School of Dentistry, Department of Oral Medicine & Pathology, Athens, Greece

Aim: The purpose of this study is to apply the Composite Radiographic Index modified (CRIm) in CBCT scans of patients with Medication related osteonecrosis of the jaws (MRONJ) in order to detect its validity, and corelate the radiologic findings with the clinical staging of the disease.

Material and Methods: This study included 43 patients with MRONJ diagnosis and CBCT scans performed in the School of Dentistry and approved by the Research Ethics Committee.

Clinical staging for every patient (0-3) was provided according to AAOMS 2022 guidelines. In cases of patients with both jaws affected, each jaw was evaluated independently resulting to 52 CBCT scans. The 52 CBCT scans were assessed under standardized viewing conditions by 2 observers who evaluated independently the following 8 radiologic features: lytic changes, sclerosis, periosteal reaction, sequestration, non-healing extraction sockets and other findings (sinus implication, inferior alveolar canal involvement, jaw fracture). The CRIm index was constructed to assess the extent of osseous changes. The radiologic features were scored as absent (0), localized/single (1), extensive/multiple (2), yielding a theoretical range of 0–12. For statistical analysis Fisher’s exact test and Spearman’s correlation coefficient were performed.

Results: A statistically significant association of clinical stage with lytic changes, sequestration and inferior alveolar canal involvement was found. Also, a statistically significant correlation of clinical stage with CRIm index classification was obtained.

Conclusion: The CRIm index tends to increase as the clinical stages of MRONJ advance suggesting, a correlation between the clinical stage of MRONJ and the CRIm index.

106: USE OF SPHERICAL SEGMENTATION RADIOMIC ANALYSIS FOR DIFFERENTIATION OF ODONTOGENIC KERATOCYSTS AND RADICULAR CYSTS

U. Seki1, A. Kuran1, A. Üzel1, O. Baysal1, E.A. Sinanoğlu1

1Kocaeli University, Kocaeli, Turkey

Aim: The primary objective of this investigation was to assess the capability of radiomics in distinguishing between odontogenic keratocyst (OKC), characterized by aggressive clinical behavior and a heightened recurrence rate, and radicular cyst (RC), an inflammatory odontogenic cyst. Additionally, this study employed an experimental spherical segmentation technique, strategically designed to unveil the inherent characteristics of the lesions under scrutiny.

Material and Methods: This retrospective group comparative research evaluated histopathologically verified cases of OKC and RC which were retrieved from archives of the Department of Oral and Maxillofacial Radiology at Kocaeli University Faculty of Dentistry. Cases possessing lesions with intact osseous boundaries and with no evidence of any perforation were included in the study. In 3D Slicer software, a total of 93 radiomic features were extracted using the SlicerRadiomics plugin for the segmented area of the lesions.

Results: The CBCT data of a total of 10 OKC and 10 RC cases were analysed. The radiomics scores obtained from the calculations had a sensitivity value of 80%, and a specificity value of 80% in predicting radicular cysts. The model was found to accurately detect radicular cysts at a rate of 80% and OKC at a rate of 80%. The radiomics score was higher in patients with OKC to those with RC (OR: 25.251; p=0.018).

Conclusion: The favorable outcomes of this study substantiate the potential utility of radiomics which may be useful before surgical intervention of RC and OKC lesions with similar radiologic features.

174: THE EFFECT OF CBCT VOXEL SIZE ON THE ASSESMENT OF SIMULATED MANDIBULAR CONDYLAR EROSIONS: A PRE-CLINICAL STUDY

Y. Youseef1, Hany M. Omar,Noha S. Abu-Taleb,Associate

1Cairo University, Oral and Maxillofacial Radiology, Cairo, Egypt

Aim: To evaluate the effect of using two different voxel sizes on the accuracy of Cone Beam Computed Tomography in the detection of simulated mandibular condylar erosions.

Materials and methods: Twelve dry human mandibles (24 condyles) were selected and simulated erosions were drilled with variable bur sizes at different depths on the five condylar surfaces (superior, anterior, posterior, medial and lateral surfaces). The mandibles were scanned using normal and high resolution protocols (voxel sizes: 0.4mm and 0.2mm respectively).

Results: Results of the current study revealed that with the CBCT normal resolution protocol (voxel sizes: 0.4 mm), the sensitivity of detection of the simulated defects ranged from 87.05 % to 94.96 % and the accuracy values from 88.9 % to 95.86 % among the observers. However, higher values were found with the high resolution protocol (voxel sizes: 0.2 mm) where the sensitivity values increased to the range of 93.53% to 97.84 % and also did the accuracy values with range of 94.44 % to 98.15 %.

Conclusion: Both normal and high resolution protocols (voxel sizes: 0.4mm and 0.2mm respectively) were comparable in the detection of the simulated mandibular condylar erosions.

199: GREY VALUES BEHAVIOR OF CONE-BEAM COMPUTED TOMOGRAPHY MACHINES – AN IN VITRO STUDY

N. Oliveira-Santos1, H. Gaêta-Araujo2, R. Spin-Neto3, D. Dagassan-Berndt4, M. Bornstein5, M.L. Oliveira6, F. Haiter-Neto6, D.Q. Freitas6, R. Schulze1

1University of Bern, School of Dental Medicine, Department of Oral Surgery and Stomatology, Division of Diagnostic Sciences, Bern, Switzerland, 2University of Sao Paulo, School of Dentistry of Ribeirao Preto, Department of Stomatology, Public Oral Health and Forensic Dentistry, Division of Oral Radiology, Ribeirao Preto, Brazil, 3University of Aarhus, Department of Dentistry and Oral Health, Section for Oral Radiology and Endodontics, Aarhus, Denmark, 4University of Basel, University Center for Dental Medicine Basel UZB, Center for Dental Imaging, Basel, Switzerland, 5University of Basel, University Center for Dental Medicine Basel UZB, Department of Oral Health and Medicine, Basel, Switzerland, 6University of Campinas, Piracicaba Dental School, Department of Oral Diagnosis, Piracicaba, Brazil

Aim: To evaluate the grey values (GV) behavior of bone and soft tissue equivalent materials and air for varying acquisition parameters in nine cone-beam computed tomography (CBCT) machines.

Material and Methods: The DIN6868-161 phantom, composed of bone equivalent material (polyvinyl chloride), soft tissue equivalent material (polymethyl methacrylate), and air gap, was scanned in nine CBCT machines (Accuitomo 170, Axeos, Eagle 3D, Newtom VGI evo, OP300, Promax, Viso G7, X1, and X800). Exposure parameters (mA, kV), field of view (FOV) dimensions, and rotation angle (if possible) were varied. The effect of the acquisition parameters on the GV was analyzed by Kruskal Wallis test for each machine independently (α=0.05).

Results: Altering mA did not influence on GV for any structure in five machines (Accuitomo 170, Axeos, , OP300, Promax, and X800). Viso G7 and X800 presented a decrease in the GV for increasing kV. For Promax and X1, the kV did not affect the GV. For the majority of machines, GV decreased with increasing FOV height. On the other hand, the GV in the Accuitomo 170 increased with the higher FOV. The rotation angle did not affect the GV of the Accuitomo and X800 machines.

Conclusion: The GV behavior of CBCT varies largely between the different machines and is mainly influenced by the FOV size, especially for bone equivalent radiodensity. For most machines, when the exposure parameters or FOV affect the GV, the GV decreases with the increase in the exposure parameters and/or FOV height.