Evaluation of Mandibular Bone Microstructure in CT Scans of People with Sickle Cell Disease.

OBJECTIVE: Sickle cell disease (SCD) is a common inherited disease, and is characterized by a genetic modification that determines the production of a hemoglobin with altered morphology. This anatomical change of hemoglobin leads to vaso-occlusive disorders and premature hemolysis of the cell, causing chronic anemia and bone marrow hyperplasia due to increased hematopoietic demand. As a consequence, several skeletal changes are reported in the skull, spine, ribs, pelvis, femur, and metatarsals. In the craniofacial region, dentofacial deformities are described, especially maxillary protrusion. However, studies evaluating bone microarchitecture are scarce. The aim of this study is to evaluate the mandibular bone microstructure of people with SCD on computed tomography (CT) scans. MATERIALS AND METHODS: Morphometric parameters were analyzed on CT scans of the mandible of people with SCD and people without this disease or any other disease affecting bone metabolism, matched for sex and age. STATISTICAL ANALYSIS: The results were compared by Student's t-test for paired samples and for an error probability of 5%. RESULTS: This study demonstrated that the mandibular bone of people with SCD presents significantly less number, connectivity and thickness of bone trabeculae, as well as having a lower fractal dimension and greater porosity. CONCLUSION: Mandibular bone of people with SCD has lower bone density and more widely spaced trabeculae.

Linear measurement accuracy of CBCT panoramic reconstructions: experimental study with dry human mandibles.

INTRODUCTION: Studies on software accuracy of reformatted panoramic computed tomography (CT) images are scarce. OBJECTIVES: The aim of this study was to evaluate the software accuracy of reformatted panoramic views from cone-beam computed tomography (CBCT). METHODS: Ten dry mandibles were scanned using CBCT with different voxel sizes. Following the reconstruction of panoramic views with three different software, horizontal and vertical linear measurements were performed using the electronic rules of each software. Measurements of the corresponding dry mandibles were taken with a digital caliper and defined as the gold standard. RESULTS: There were no statistically significant differences in linear distances among the dry mandibles and reformatted panoramic CT views. The relative error ranged from 1.3 to 8.0%, depending on the software and voxel size. CONCLUSIONS: The linear measurements on reformatted panoramic views are reliable.

Bacterial diversity and prevalence of antibiotic resistance genes in the oral microbiome.

OBJECTIVES: This study aims to describe the oral microbiome diversity and prevalence of ARGs in periodontal health and disease. BACKGROUND: The human oral cavity harbors a complex microbial community known as the oral microbiome. These organisms are regularly exposed to selective pressures, such as the usage of antibiotics, which drive evolution and acquisition of antibiotic resistance genes (ARGs). Resistance among oral bacteria jeopardizes not only antibiotic therapy for oral infections, but also extra-oral infections caused by bacterial translocation. METHODS: We carried out a cross-sectional investigation. Saliva and subgingival plaque samples were collected during a clinical exam. 16S rRNA gene sequencing was performed to assess microbial diversity. Resistance genes were identified through PCR assays. RESULTS: Of the 110 participants, only 22.7% had healthy periodontium, while the majority was diagnosed with gingivitis (55.4%) and chronic periodontitis (21.8%). The composition of the oral microbiota differed from healthy and diseased samples, being Streptococcus spp. and Rothia spp. predominant in periodontal disease. Regarding ARGs, 80 (72.7%) samples were positive for at least one of genes screened, erm being the most frequent variant (58.2%), followed by blaTEM (16.4%), mecA (2.7%), pbp2b and aac(6 ') (1.8%). Neither genes coding resistance to carbapenems nor metronidazole were detected. CONCLUSIONS: Our findings indicate that there are no significant differences in terms of taxonomic enrichment between healthy and diseased oral microbiomes. However, samples retrieved from healthy patients had a more diverse microbial community, whereas diseased samples have lower taxonomic diversity. We have also identified clinically relevant ARGs, providing baseline information to guide antibiotic prescription in dentistry.