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Background/Aim: The primary aim was to evaluate the prevalence and localisation of dental injuries caused by osteosynthesis screws during orthognathic surgery, comparing two different CAD/CAM planning/surgical approaches through retrospective evaluation of post-operative computed tomography. Material and Methods: This study considered all patients who underwent orthognathic surgery from 2010–2019. The examination for dental root injuries between conventional osteosynthesis (Maxilla conventional cohort) and osteosynthesis with patient-specific implant (Maxilla PSI cohort) was performed by evaluating the post-operative CT scans. Results: A total of 126 patients were included in the study. Among the 61 patients of the Maxilla conventional cohort, 10 dental root injuries in 8 patients (13.1%) were detected in the post-operative CT scan, representing 1.5% (n = 10/651) of the osteosynthesis screws inserted in proximity of the alveolar crest. No dental injury occurred following osteosynthesis in the 65 patients of the Maxillary PSI cohort (n = 0/773 screws) (p < 0.001). During a mean follow-up period of 13 months after primary surgery, none of the injured teeth showed evidence of periapical alterations and no endodontic treatments were necessary. Conclusions: Maxillary positioning using CAD/CAM-fabricated drill/osteotomy guide and osteosynthesis with PSI can significantly reduce the risk for dental injury compared to the conventional procedure. However, the clinical significance of the detected dental injuries was rather minor.

Additive manufacturing has proven to be a viable alternative to conventional manufacturing methodologies for metallic implants due to its capability to customize and fabricate novel and complex geometries. Specific to its use in dental applications, various groups have reported successful outcomes for customized root-analog dental implants in preclinical and clinical studies. However, geometrical accuracy of the fabricated samples has never been analyzed. In this article, we studied the geometric accuracy of a 3D printed titanium dental implant design against the tooth root of the monkey maxilla incisor. Monkey maxillas were scanned using cone-beam computed tomography, then segmentation of the incisor tooth roots was performed before the fabrication of titanium dental implants using a laser powder bed fusion (PBF) process. Our results showed 68.70% ± 5.63 accuracy of the 3D printed dental implant compared to the actual tooth (n = 8), where main regions of inaccuracies were found at the tooth apex. The laser PBF fabrication process of the dental implants showed a relatively high level of accuracy of 90.59% ± 4.75 accuracy (n = 8). Our eventual goal is to develop an accurate workflow methodology to support the fabrication of patient-specific 3D-printed titanium dental implants that mimic patients' tooth anatomy and fit precisely within the socket upon tooth extraction. This is essential for promoting primary stability and osseointegration of dental implants in the longer term.

[...]molar status was determined based on patient's OPG. [...]molar was considered impacted if it was not in functional occlusion and, at the same time, its roots were fully formed. According to the present study, 37.7% showed third molar impaction, which agrees with the above results, i.e. the present study agrees with the previous investigations performed to access the impaction rate. [...]South Indian population has very much shown the same result as in other parts of the world.

Objective The aim of this study was to evaluate the efficacy of supplementary techniques (ultrasonic tip/XP-endo Finisher R) in removing remaining filling materials (gutta-percha/AHPlus/BCSealer) from oval-shaped root canals during non-surgical endodontic retreatment. Material and methods Twenty-eight distal roots of human mandibular molars with single and oval-shaped canals were initially shaped with a R40 instrument and filled with gutta-percha points and AH Plus ( n  = 14) or BC Sealer ( n  = 14) followed by an initial micro-CT scanning. Initial filling material removal was performed in all 28 samples with an R50 instrument, and all samples submitted to a second micro-CT. Supplementary techniques with ultrasonic tips or XP-endo Finisher R instruments were performed in each sealer group, and all samples submitted to a third micro-CT. The volume of remaining filling material was calculated for the entire canal as well as for the coronal, middle, and apical thirds. Statistical analyses were performed using T, ANOVA 3-way, and Tukey tests. Results Lower values of remnant filling material were found for BC Sealer (16.06 ± 14.34) compared to AH Plus (28.30 ± 10.54) ( P  < 0.001), and considering the supplementary technique, lower values of remnant filling material were found for the ultrasonic tip (18.95 ± 11.05) compared to XP-endo Finisher R (25.41 ± 15.81) ( P  = 0.025). Ultrasonic instruments significantly reduced the percentage of remaining filling material for both AH Plus ( P  = 0.04) and BC Sealer ( P  = 0.02) while XP-endo Finisher R was effective for AHPlus only ( P  = 0.04). The remaining filling material was observed in all samples regardless the filling material or the supplementary technique employed. Conclusions Supplementary techniques increased filling material removal; however, none of them was able to render root canals completely free from root fillings. Ultrasonic tips should be considered a good option for endodontic retreatment, especially for bioceramic cases. Clinical relevance Supplementary instrumentation techniques are effective tools to reduce the amount of filling materials during root canal retreatment.

aa6435@my.bristol.ac.uk Mollet and colleagues call for a rights based approach to children’s oral health.1 There is an established link between poor oral health and lower socioeconomic status. In 1905, James Kerr, a medical doctor, and Charles Edward Wallis, one of the earliest known dually qualified doctor-dentists, worked with the London County Council to establish the London School Dental Service to combat poor oral and dental health among schoolchildren.3 Meanwhile, legislation was enacted to ensure the provision of food with nutritional value (including fruits high in vitamin C essential for gum health) and mandatory check-ups for schoolchildren by clinical professionals.45 The work of Kerr and Wallis highlights two things: the necessity of input from the state and the power of collaboration and allyship between clinical practitioners and the state for effective preventive intervention. [...]the idea of a rights based approach commonly adopted by the United Nations, which has its roots in democratic ideology,7 might be worrying or even considered abhorrent to a state led by an oligarch or autocrat.89 At the capitalist end of the spectrum, a state’s government might be beholden to lobbies and corporations that sell or endorse products detrimental to oral health.10 Pragmatically speaking, advocating for a rights based approach in democratic nations is appropriate, but such ideology might be neither appropriate nor effective in less democratic nations.

Background Artificial intelligence (AI) has been introduced to interpret the panoramic radiographs (PRs). The aim of this study was to develop an AI framework to diagnose multiple dental diseases on PRs, and to initially evaluate its performance. Methods The AI framework was developed based on 2 deep convolutional neural networks (CNNs), BDU-Net and nnU-Net. 1996 PRs were used for training. Diagnostic evaluation was performed on a separate evaluation dataset including 282 PRs. Sensitivity, specificity, Youden’s index, the area under the curve (AUC), and diagnostic time were calculated. Dentists with 3 different levels of seniority (H: high, M: medium, L: low) diagnosed the same evaluation dataset independently. Mann-Whitney U test and Delong test were conducted for statistical analysis (ɑ=0.05). Results Sensitivity, specificity, and Youden’s index of the framework for diagnosing 5 diseases were 0.964, 0.996, 0.960 (impacted teeth), 0.953, 0.998, 0.951 (full crowns), 0.871, 0.999, 0.870 (residual roots), 0.885, 0.994, 0.879 (missing teeth), and 0.554, 0.990, 0.544 (caries), respectively. AUC of the framework for the diseases were 0.980 (95%CI: 0.976–0.983, impacted teeth), 0.975 (95%CI: 0.972–0.978, full crowns), and 0.935 (95%CI: 0.929–0.940, residual roots), 0.939 (95%CI: 0.934–0.944, missing teeth), and 0.772 (95%CI: 0.764–0.781, caries), respectively. AUC of the AI framework was comparable to that of all dentists in diagnosing residual roots (p > 0.05), and its AUC values were similar to (p > 0.05) or better than (p < 0.05) that of M-level dentists for diagnosing 5 diseases. But AUC of the framework was statistically lower than some of H-level dentists for diagnosing impacted teeth, missing teeth, and caries (p < 0.05). The mean diagnostic time of the framework was significantly shorter than that of all dentists (p < 0.001). Conclusions The AI framework based on BDU-Net and nnU-Net demonstrated high specificity on diagnosing impacted teeth, full crowns, missing teeth, residual roots, and caries with high efficiency. The clinical feasibility of AI framework was preliminary verified since its performance was similar to or even better than the dentists with 3–10 years of experience. However, the AI framework for caries diagnosis should be improved.

Objectives The purpose of this study was to assess the efficacy of different final irrigation activation methods in removing debris and smear layer in the apical, middle, and coronal portion of straight root canals. Material and methods Straight root canals of 58 freshly extracted mandibular premolars were used. Root canals were prepared to size 40.06. Irrigation was performed using 3% sodium hypochlorite. Samples were divided into four equal groups ( n  = 12) according to the irrigation activation techniques: (A) manual irrigation (MI), (B) EndoActivator (EA) (Dentsply Maillefer, Ballaigues, Switzerland), (C) sonic activation EDDY (EDDY; VDW, Munich, Germany), and (D) passive ultrasonic irrigation (PUI). Ten teeth served as negative controls. Roots were split longitudinally, and the canal walls were subjected to scanning electron microscopy. The presence of debris and smear layer at coronal, middle, and apical levels were evaluated using a 5-point scoring system and statistically analyzed using Kruskal-Wallis and chi-square tests. Results Canal cleanliness decreased from coronal to apical ( P  = 0.035). Significantly more debris was removed with EA, EDDY, and PUI compared to MI ( P  < 0.001; total values), but no differences were observed in the different portions of the root canals ( P  > 0.05). Smear layer removal with PUI, EA, and EDDY was not significantly different ( P  > 0.05), but only EDDY and PUI were superior to MI ( P  < 0.01). Conclusion All activation methods created nearly debris-free canal walls and were superior compared to manual irrigation ( P  < 0.001). EDDY and PUI also showed significantly better smear layer scores compared to manual irrigation. Clinical relevance The sonic activation system EDDY performed equally as well as PUI, and both methods were significantly superior compared with manual irrigation in straight root canals with regard to debris and smear layer removal.

Background The clinician should have complete knowledge of the normal anatomy of the root as well as complexities in the root canal configuration for a better outcome, as missed or improper handling of the canal system can lead to the failure of an entire endodontic procedure. The present study aims to assess the morphology of roots and canals in permanent mandibular premolars in the Saudi subpopulation with a new classification system. Methods The present study includes 1230 mandibular premolars (645 first premolars and 585-second premolars) from 500 CBCT images of the patients, including retrospective data. iCAT scanner system (Imaging Sciences International, Hatfield, PA, USA) was used to obtain the images; scanning of 8 × 8 cm images was performed at 120 KVp and 5–7 mA with a voxel size of 0.2 mm. The new method of classification presented by Ahmed et al. 2017 was used to record and classify the root canal morphology, followed by recording the differences regarding the age and gender of the patients. Comparison of canal morphology in lower permanent premolars and its association with gender and age of the patients was done by Chi-square test/ Fisher exact test; the significance level was set at 5% (p ≤ 0.05). Results The left mandibular 1st and 2nd premolars with one root were 47.31%, with two roots were 2.19%. However, three roots (0.24%) and C-shaped canals (0.24%) were reported only in the left mandibular 2nd premolar. The right mandibular 1st and 2nd premolars with one root were 47.56%, with two roots were 2.03%. The overall percentage of the number of roots and canals in the first and second premolars 1 PM 1 (88.38%), 2 PM 1 B 1  L 1 (3.5%), 2 PM B 1  L 1 (0.65%), 1 PM 1–2−1 (3.08%), 1 PM 1–2 (3.17%), 1 PM 1–2−1–2 (0.24%), 3 PMMB 1 DB 1 L 1 (0.48%). However, the C-shaped canals (0.40%) were reported in right and left mandibular second premolars. No statistically significant difference was reported between mandibular premolars and gender. A statistically significant difference was reported between mandibular premolars and the age of the study subjects. Conclusion Type I ( 1 TN 1 ) was the major root canal configuration in permanent mandibular premolars, which was higher among males. The CBCT imaging provides thorough details about the root canal morphology of lower premolars. These findings could support diagnosis, decision-making, and root canal treatment, for dental professionals.

Objectives The aim of this study was to assess cone beam computed tomography (CBCT) as a root canal anatomy diagnostic tool by comparison with micro-CT gold-standard. Materials and methods 216 two-rooted mandibular molars were first scanned in a CBCT device (200 μm voxel size) and posteriorly in a micro-CT scanner (19.61 μm). The volumes were sequentially screened to classify main root canal anatomy according to Vertucci classification, and for the presence of lateral canals and apical deltas, in both mesial and distal roots. Results Both methods revealed a higher prevalence of Vertucci Type II and IV in the mesial root, and Vertucci Type I in the distal root. The percentage of agreement for main root canal anatomy classification between CBCT and micro-CT scores was high (85.2%). Conclusion Sensibility to detect both lateral canals and apical deltas with CBCT was low. These results attest to the fact that minor anatomical changes might be difficult to identify with CBCT imaging, hampering its diagnostic value.

ObjectivesThis study aims to assess the obturation efficacy of sealers placed with different techniques using microcomputed tomography (µCT) and assess the influence of µCT testing parameters on the obturation data obtained.Materials and methodsIncisors and mesial roots of lower molars with standardized root length were scanned using µCT, and one tooth of each type was 3D printed in acrylic. Two obturation techniques (warm vertical and single cone) and 4 sealer types (AH Plus, BioRoot RCS, Totalfill BC, and Bio-C Sealers) were assessed following storage in Hank’s balanced salt solution for 3 and 6 months by assessing gap and void volume percentages on both natural and replica incisor and molar roots. The storage solution was analysed to assess calcium ion leaching. The influence of temperature, tooth positioning, and moisture content of the teeth while µCT scanning was also investigated.ResultsThe obturation quality in the incisor group was the same using both natural teeth and replicas (p > 0.05). No changes in void volume were identified when comparing the same sealer using different obturation techniques. The premixed sealers used in single-cone obturation exhibited high void volume in the 3D printed replicas in the long term. The temperature, positioning, and moisture content of the teeth did not affect the outcome of µCT testing.ConclusionsBioRoot RCS, Totalfill BC, and Bio-C Sealers are suitable for obturation of both complex and simple root canal systems using different obturation techniques with BioRoot RCS exhibiting the highest calcium ion release. 3D printed acrylic teeth can be used to assess the obturation quality in uncomplicated root canal systems. µCT parameters had no significant effect on the µCT measurement.Clinical relevanceThe single-cone obturation technique with hydraulic sealer is a simple technique that can be used for obturation of all root canal systems.