Generative adversarial neural networks (GAN) have been demonstrating efficacy in increasing the quality of tomographic images. However, there is a lack of information about its effectiveness in cone-beam CT (CBCT). This study evaluated the performance of GAN in reducing CBCT artefacts. A phantom was custom-made with a mandible covered with Mix-D. Forty teeth were endodontically instrumented and inserted in mandibular sockets. CBCT scans were obtained with a field-of-view of 5 x 5 cm, 90kVp, 3 mA, 0.08 mm voxel size and 9 s. All scans were repeated after enabling metal artefact reduction (MAR). Two conditions with high-density materials were simulated and additional scans were performed. GAN was tailored to use the acquired raw images for validation, training and testing. Structural similarity index (SSIM), peak signal-to-noise ratio (PSNR), mean absolute error (MAE) and root mean square error (RMSE) were calculated. Then, all the images were reconstructed and noise and signal-to-noise ratio (SNR) were measured in the cervical, middle and apical third of the second left premolar root. Also, assessments of the diagnostic confidence, artefact interference and dental and bone preservation were performed by four observers. All the conditions were compared using ANOVA two-way (alpha = 0,05) and Wilcoxon signed rank test. The corrected images showed significantly higher SSIM and PSNR, lower MAE and RMSE, lower noise, higher SNR, higher diagnostic confidence, lower artefact interference and high dental and bone preservation. The CBCT images with MAR and higher presence of high-density materials showed significantly lower noise values. The developed neural network has promising performance to increase the image quality of CBCT raw and reconstructed images.

Introduction: Cemento-osseous dysplasia (COD) is a benign fibro-osseous lesion of the jaws, often asymptomatic but potentially complicated by secondary infection due to its hypovascular nature. Osteomyelitis may occur following minor trauma or dental procedures when the condition is unrecognized or improperly managed. Case report: A 52-yr-old woman of African descent developed osteomyelitis of the right mandible after multiple tooth extractions performed abroad. CBCT imaging revealed bilateral florid COD with mixed radiolucent–radiopaque lesions and bone sequestra. Conservative surgical debridement under local anesthesia, followed by prolonged antibiotic therapy, allowed symptom resolution, full mucosal healing, and bone remodeling. Discussion: This case illustrates the iatrogenic risk of invasive procedures in unrecognized COD. The hypovascular, sclerotic bone limits healing and antibiotic diffusion, predisposing to chronic infection. Previous reports similarly describe secondary osteomyelitis arising in florid COD and support conservative management combining limited debridement and prolonged antibiotic therapy. Early radiographic recognition and pulp vitality testing of teeth with unexplained periapical radiolucencies are key to preventing misdiagnosis. When infection occurs, conservative management, when possible, ensures optimal outcomes. Conclusion: Clinicians should suspect COD in middle-aged women of African descent presenting with mixed mandibular lesions. Early diagnosis and avoidance of unnecessary extractions can prevent osteomyelitis and reduce morbidity.

OBJECTIVE:We aimed to assess whether the presence of a therapy dog during 2 dental care sessions could facilitate subsequent dog-free dental care for anxious autistic children who had difficulty cooperating. METHODS:We conducted a parallel-arm randomized trial: control group using usual behavioral strategies only and experimental group using animal-assisted therapy (AAT) strategies combined with usual behavioral strategies. All patients had 3 dental care sessions. In the experimental group, the therapy dog was present during the first 2 dental sessions, and the third dental session was dog-free. The primary outcome was the mean overall anxiety during the dog-free third treatment session. Generalized estimating equations (GEEs) were also used to account for the correlation of repeated measures. RESULTS:A total of 49 patients were enrolled. The most frequently usual behavioral strategies were positive reinforcement (n = 31; 64%), hypnosis (n = 28; 58%), demystification (n = 26; 52%), and in vivo modeling (n = 25; 51%). AAT-specific strategies included imitating dog (n = 18; 69%), positive supportive reinforcement with dog incentives (n = 14; 54%), and distraction or therapeutic touch (n = 11; 42%). Mean anxiety scores were significantly lower in the experimental group during the third session (mean difference, -1.4; 95% CI, -2.43 to -0.37). GEE analysis showed a significant reduction in anxiety over time in the experimental group compared with controls (P = .0001; β = -1.03). CONCLUSION:Dog served mainly as an in vivo model and positive reinforcer. Our findings suggest that AAT could play a key role in helping children acclimate to dental procedures, and, consequently, ease the transition back to conventional, animal-free dental treatments.

Orofacial bone tissue engineering addresses bone loss caused by trauma, malformations, or tumors, enabling restoration and implant rehabilitation. Angiogenesis plays a crucial role in osteogenesis by ensuring nutrient and oxygen transport essential for bone regeneration. Preclinical large animal models are vital for translational research and require noninvasive, nondestructive methods aligned with 3Rs principles (Replacement, Reduction, and Refinement) to assess angiogenesis. This study proposes high-resolution cone-beam computed tomography subtraction angiography (HR-CBCT-SA) adapted for the orofacial region as an innovative method for monitoring angiogenesis during jawbone regeneration. Three Yucatan minipigs with a surgically created buccal wall jawbone defect per hemimandible were followed for 90 days by CBCT-SA to assess vascular remodeling. Morphometric parameters, including vessel number, node count, radius, and length, were analyzed and validated against histological morphometry. CBCT-SA revealed vascular dynamics during healing. By day 10, increased vessel and node counts along with reduced vessel radius and length indicated neoangiogenesis. At day 30, vessel maturation was aligned with transition of fibrous tissue to osteoid matrix deposition. By day 90, vascular metrics stabilized, reflecting bone remodeling phases characterized by replacement of lamellar and medullary bone replacement. Extrabony vascular networks underwent more pronounced changes than intrabony vessels, underscoring the leading role of periosteum in regeneration. Histology validated CBCT-SA findings, although resolution limitations prevented detection of vessels smaller than 500 µm. Nevertheless, CBCT-SA captured angiogenic changes over time and supported nondestructive monitoring without compromising tissue integrity. This study establishes HR-CBCT-SA as a reliable, nondestructive imaging technique for assessing vascular changes during jawbone regeneration in preclinical models. It demonstrates significant translational potential because of the clinically validated use of CBCT-angiography. Advances in artificial intelligence (AI)-driven image analysis are expected to enhance sensitivity and accuracy, improving vascular assessment. Moreover, this approach can be extended for investigating vascular-related oral pathologies (e.g., radiochemical osteonecrosis of the jaws), offering valuable tool to advance research in jawbone regeneration.

Impact statement This systematic review investigates porcine, canine, and ovine models for current oral cell-based regeneration procedures, and researchers could refer to it for the choice of the most pertinent preclinical model for a given cell-based therapeutics. The recent advances in the field of cell-based therapeutics open promising perspectives for oral tissue regeneration. The development of large animal models, which overcome the limits of the rodent models and allow to emulate clinical situations, is crucial for the validation of regenerative strategies to move toward clinical application. Currently, porcine, canine, and ovine models are mainly developed for oral regeneration and their specific characteristics have an impact on the outcomes of the studies. Thus, this systematic review investigates the application of porcine, canine, and ovine models in present cell-based oral regeneration, according to the species characteristics and the targeted tissue to regenerate. A customized search of PubMed, EMBASE, Scopus, and Web of Science databases from January 2015 to March 2020 was conducted. Relevant articles about cell-based oral tissues engineering in porcine, canine, and ovine models were evaluated. Among the evaluated articles, 58 relevant studies about cell-based oral regeneration in porcine, canine, and ovine models matched the eligibility criteria and were selected for full analysis. Porcine models, the most similar species with humans, were mostly used for bone and periodontium regeneration; tooth regeneration was reported only in pig, except for one study in dog. Canine models were the most transversal models, successfully involved for all oral tissue regeneration and notably in implantology. However, differences with humans and ethical concerns affect the use of these models. Ovine models, alternative to porcine and canine ones, were mainly used for bone and, scarcely, periodontium regeneration. The anatomy and physiology of these animals restrain their involvement. If consistency was found in defect specificities and cell trends among different species animal models of bone, dentin-pulp complex, or tooth regeneration, variability appeared in periodontium. Regeneration assessment methods were more elaborate in porcines and canines than in ovines. Risk of bias was low for selection, attrition and reporting, but unclear for performance and detection. Overall, if none of the large animal models can be considered an ideal one, they are of deemed importance for oral cell-based tissue engineering and researchers should consider their relevance to establish favorable conditions for a given preclinical cell-based therapeutics.

There is an inverse relationship between the differentiation of mesenchymal stem cells (MSCs) along either an adipocyte or osteoblast lineage, with lineage differentiation known to be mediated by transcription factors PPARγ and Runx2, respectively. Endogenous ligands for PPARγ are generated during the hydrolysis of triacylglycerols to fatty acids through the actions of lipases such as hormone sensitive lipase (HSL). To examine whether reduced production of endogenous PPARγ ligands would influence bone regeneration, we examined the effects of HSL knockout on fracture repair in mice using a tibial mono-cortical defect as a model. We found an improved rate of fracture repair in HSL-ko mice documented by serial μCT and bone histomorphometry compared to wild-type (WT) mice. Similarly, accelerated rates of bone regeneration were observed with a calvarial model where implantation of bone grafts from HSL-ko mice accelerated bone regeneration at the injury site. Further analysis revealed improved MSC differentiation down osteoblast and chondrocyte lineage with inhibition of HSL. MSC recruitment to the injury site was greater in HSL-ko mice than WT. Finally, we used single cell RNAseq to understand the osteoimmunological differences between WT and HSL-ko mice and found changes in the pre-osteoclast population. Our study shows HSL-ko mice as an interesting model to study improvements to bone injury repair. Furthermore, our study highlights the potential importance of pre-osteoclasts and osteoclasts in bone repair.

Stem cells contained within the dental mesenchymal stromal cell (MSC) population are crucial for tissue homeostasis. Assuring their genomic stability is therefore essential. Exposure of stem cells to ionizing radiation (IR) is potentially detrimental for normal tissue homeostasis. Although it has been established that exposure to high doses of ionizing radiation (IR) has severe adverse effects on MSCs, knowledge about the impact of low doses of IR is lacking. Here we investigated the effect of low doses of X-irradiation with medical imaging beam settings (<0.1 Gray; 900 mGray per hour), in vitro , on pediatric dental mesenchymal stromal cells containing dental pulp stem cells from deciduous teeth, dental follicle progenitor cells and stem cells from the apical papilla. DNA double strand break (DSB) formation and repair kinetics were monitored by immunocytochemistry of γH2AX and 53BP1 as well as cell cycle progression by flow cytometry and cellular senescence by senescence-associated β-galactosidase assay and ELISA. Increased DNA DSB repair foci, after exposure to low doses of X-rays, were measured as early as 30 min post-irradiation. The number of DSBs returned to baseline levels 24 h after irradiation. Cell cycle analysis revealed marginal effects of IR on cell cycle progression, although a slight G 2 /M phase arrest was seen in dental pulp stromal cells from deciduous teeth 72 h after irradiation. Despite this cell cycle arrest, no radiation-induced senescence was observed. In conclusion, low X-ray IR doses (< 0.1 Gray; 900 mGray per hour), were able to induce significant increases in the number of DNA DSBs repair foci, but cell cycle progression seems to be minimally affected. This highlights the need for more detailed and extensive studies on the effects of exposure to low IR doses on different mesenchymal stromal cells.

Objectives. The objective of this study was to evaluate the influence of voxel size on artifacts arising from the exomass in cone beam computed tomography (CBCT). Study Design. An imaging phantom was scanned using 2 CBCT units, each adjusted to 2 voxel sizes: 0.2 and 0.3 mm. From 1 to 3 metal inserts of titanium, cobalt-chromium, or amalgam were placed in the exomass and additional CBCT scans were acquired. Mean voxel gray values were obtained from 16 homogeneous areas of the phantom and averaged, and the standard deviation was calculated to obtain voxel gray value variability. The data were analyzed using 2-way analysis of variance, Tukey, and Dun nett tests (a =.05). Results. Overall, mean voxel gray values and voxel gray value variability did not differ significantly between CBCT scans obtained with voxel sizes of 0.2 and 0.3 mm for either CBCT model tested (P .05). Despite some exceptions in which significant differences were observed between the 2 voxel sizes (P < .05), the mean voxel gray values and voxel gray value variability resulting from different metal compositions and, in most situations, for different numbers of metal inserts in the exomass were not affected. Conclusion. Voxel size has little influence on exomass-related CBCT artifacts. (Oral Surg Oral Med Oral Pathol Oral Radiol 2021;132:456-464)

BACKGROUND:During the first-wave of the COVID-19 pandemic, dentists were considered at high-risk of infection. In France, to stop the spread of SARS-CoV-2, a nationwide lockdown was enforced, during which dentists suspended their routine clinical activities, working solely on dental emergencies. This measure has had an indisputable mitigating effect on the pandemic. To continue protecting dentists after suspension of nationwide lockdown, implementation of preventive measures was recommended, including adequate personal protective equipment (PPE) and room aeration between patients. No study has explored whether implementation of such preventive measures since the end of the first-wave has had an impact on the contamination of dentists.METHODS:An online survey was conducted within a French dentist population between July and September 2020. To explore risk factors associated with COVID-19, univariate and multivariate logistic regression analyses were performed.RESULTS:The results showed that COVID-19 prevalence among the 3497 respondents was 3.6%. Wearing surgical masks during non-aerosol generating procedures was a risk factor of COVID-19, whereas reducing the number of patients was a protective factor.CONCLUSIONS:Considering the similar COVID-19 prevalence between dentists and the general population, such data suggest that dentists are not overexposed in their work environment when adequate preventive measures are applied.IMPACT:Dentists should wear specific PPE (FFP2, FFP3 or (K)N95 masks) including during non-aerosol generating procedures and reduce the number of patients to allow proper implementation of disinfection and aeration procedures. Considering the similarities between COVID-19 and other viral respiratory infections, such preventive measures may also be of interest to limit emerging variants spread as well as seasonal viral outbreaks.

Comme pour tout traitement, la prescription d’inhibiteurs de la résorption osseuse (IRO) implique de mettre en balance les bénéfices et les risques attendus du traitement. Peu fréquente mais invalidante, l’ostéonécrose des mâchoires d’origine médicamenteuse (ONM) n’en reste pas moins l’effet indésirable le plus redouté des patients(e)s comme de certains professionnels de santé, possiblement en rapport avec une méconnaissance des éléments constituant cette balance bénéfices/risques. Une approche multidisciplinaire concertée, la prévention primaire via la réalisation systématique d’un bilan bucco-dentaire préthérapeutique dès lors que la situation clinique le permet, mais aussi l’instauration d’un suivi oral régulier permettent de considérablement limiter le risque d’ONM associé aux IRO, de faciliter l’adhérence au traitement et d’améliorer la qualité des soins.

Dose optimisation has been revisited in the literature due to the frequent use of cone beam computed tomography (CBCT). Although the reduction of the field-of-view (FOV) size has shown to be an effective strategy, this indirectly increases the negative effect from the exomass. The aim of this study was to evaluate the diagnostic accuracy of an optimised CBCT protocol in the detection of simulated vertical root fracture (VRF) in the presence of metal in the exomass and/or inside the FOV. Twenty teeth were endodontically instrumented and VRF was induced in half of them. All teeth were individually placed in a human mandible covered with a soft tissue equivalent material, metallic materials were placed at different dispositions in the exomass and/or endomass, and CBCT scans were obtained at two dose protocols: standard and optimised. Five radiologists evaluated the images and indicated the presence of VRF using a 5-point scale. Area under the ROC curve (AUC), sensitivity, and specificity were calculated and compared using ANOVA (α = 0.05). Overall, AUC, sensitivity, and specificity did not differ significantly (p > 0.05) between the dose protocols. In conclusion, optimised dose protocols should be considered in the detection of simulated VRF irrespective of the occurrence of artefacts from metallic materials in the exomass and/or inside the FOV.

Dose optimisation has been revisited in the literature due to the high frequency of cone-beam CT (CBCT) scans and, the reduction of the field-of-view (FOV) size has shown to be an effective strategy. However, small FOV scans have negative influences of the truncation effect from the exomass.The aim of this study was to evaluate the diagnostic accuracy of an optimised CBCT protocol for the detection of simulated vertical root fracture (VRF) in the presence of metallic artefacts from the exomass and/or endomass.Twenty teeth were endodontically instrumented and VRF was induced in half of them. All teeth were individually placed in a human mandible, metallic materials were placed in the exomass and/or endomass, and CBCT scans were obtained at two dose protocols: standard and optimised. Three radiologists evaluated the images and indicated the presence of VRF using a 5-point scale. Sensitivity, specificity and area under the ROC curve (AUC) were obtained and compared using ANOVA (α=0.05). Overall, sensitivity, specificity and AUC did not differ significantly (p>0.05) between the dose protocols.In conclusion, optimised protocols should be considered in the detection of simulated VRF irrespective of the occurrence of artefacts from metallic materials in the exomass and/or endomass.

ALARA is a well-known principle that has been used to identify optimization of x-ray exposure in the field of radiology since the seventies. While ALARA implies the responsibility to minimize radiation exposures to a level As Low As Reasonably Achievable, some years ago, a variation of the acronym, ALADA, was proposed which took into account the evolution of imaging technology and any related dose increases 1 .

Background Previous studies have highlighted the increased risk of contracting the COVID-19 for health-care workers and suggest that oral health-care workers may carry the greatest risk. Considering the transmission route of the SARS-CoV-2 infection, a similar increased risk can be hypothesized for other respiratory infections. However, no study has specifically assessed the risk of contracting COVID-19 within the dental profession. Methods An online survey was conducted within a population of French dental professionals between April 1 and April 29, 2020. Univariable and multivariable logistic regression analyses were performed to explore risk indicators associated with laboratory-confirmed COVID-19 and COVID-19-related clinical phenotypes (i.e. phenotypes present in 15% or more of SARS-CoV-2-positive cases). Results 4172 dentists and 1868 dental assistants responded to the survey, representing approximately 10% of French oral health-care workers. The prevalence of laboratory-confirmed COVID-19 was 1.9% for dentists and 0.8% for dental assistants. Higher prevalence was found for COVID-19-related clinical phenotypes both in dentists (15.0%) and dental assistants (11.8%). Chronic kidney disease and obesity were associated with increased odds of laboratory-confirmed COVID-19, whereas working in a practice limited to endodontics was associated with decreased odds. Chronic obstructive pulmonary disease, use of public transportation and having a practice limited to periodontology were associated with increased odds of presenting a COVID-19-related clinical phenotype. Moreover, changes in work rhythm or clinical practice were associated with decreased odds of both outcomes. Conclusions Although oral health-care professionals were surprisingly not at higher risk of COVID-19 than the general population, specific risk indicators could exist, notably among high aerosol-generating dental subspecialties such as periodontology. Considering the similarities between COVID-19-related clinical phenotypes other viral respiratory infections, lessons can be learned from the COVID-19 pandemic regarding the usefulness of equipping and protecting oral health-care workers, notably during seasonal viral outbreaks, to limit infection spread. Impact Results from this study may provide important insights for relevant health authorities regarding the overall infection status of oral health-care workers in the current pandemic and draw attention to particular at-risk groups, as illustrated in the present study. Protecting oral health-care workers could be an interesting public health strategy to prevent the resurgence of COVID-19 and/or the emergence of new pandemics.

Objectives: This review aimed to present studies that prospectively investigated biological effects in patients following diagnostic dentomaxillofacial radiology (DMFR). Methods: Literature was systematically searched to retrieve all studies assessing radiobiological effects of using X-ray imaging in the dentomaxillofacial area, with reference to radiobiological outcomes for other imaging modalities and fields. Results: There is a lot of variability in the reported radiobiological assessment methods and radiation dose measures, making comparisons of radiobiological studies challenging. Most radiological DMFR studies are focusing on genotoxicity and cytotoxicity, data for 2D dentomaxillofacial radiographs, albeit with some methodological weakness biasing the results. For CBCT, available evidence is limited and few studies include comparative data on both adults and children. Conclusions In the future, one will have to strive towards patient-specific measures by considering age, gender and other individual radiation sensitivity-related factors. Ultimately, future radioprotection strategies should build further on the concept of personalized medicine, with patient-specific optimization of the imaging protocol, based on radiobiological variables.

Background Bone debris generated during site preparation is generally evacuated with irrigation; here, we evaluated whether retention of this autologous material improved the rate of peri-implant bone formation. Methods In 25 rats, a miniature implant system composed of an osseo-shaping tool and a tri-oval-shaped implant was compared against a conventional drill and round implant system. A split-mouth design was used, and fresh extraction sockets served as implant sites. Histology/histomorphometry, immunohistochemistry, and microcomputed tomography (mu CT) imaging were performed immediately after implant placement, and on post-surgery days 3, 7, 14, and 28. Results Compared with a conventional drill design, the osseo-shaping tool produced a textured osteotomy surface and viable bone debris that was retained in the peri-implant environment. Proliferating osteoprogenitor cells, identified by PCNA and Runx2 expression, contributed to faster peri-implant bone formation. Although all implants osseointegrated, sites prepared with the osseo-shaping tool showed evidence of new peri-implant bone sooner than controls. Conclusion Bone debris produced by an osseo-shaping tool directly contributed to faster peri-implant bone formation and implant osseointegration.