Dentition

ObjectivesThis study explores the subsistence strategies of Middle-to-Late Holocene human populations in the Argentinean Pampas and Paraná River Delta by analyzing dental microwear patterns.Materials and methodsWe examined occlusal molar microwear textures of individuals from the Middle and Late Holocene recovered from 12 archaeological sites across three ecologically distinct areas: the Upper Delta of the Paraná River, Central Pampas, and the lower Colorado River Valley.ResultsOur results reveal both expected and unexpected trends. Individuals from the resource-rich Upper Delta of the Paraná River exhibited the predicted high dietary diversity (indicated by elevated mean heterogeneity (Hasfc81) values) but also showed surprisingly high mean complexity values (Asfc)-exceeding even those from the two semi-arid areas (Central Pampas and lower Colorado River Valley), where environmental abrasives would have been expected to have resulted in greater microwear texture complexity.DiscussionWithin the Paraná Delta, significant intra-site variation at Los Tres Cerros 1 suggests differential food access, possibly tied to social stratification in the Goya-Malabrigo archaeological entity. In the Central Pampas, Middle Holocene individuals from the Arroyo Seco 2 archaeological site displayed greater dietary heterogeneity than contemporaneous and Late Holocene sites, contradicting expectations of progressive diversification during this period. These findings underscore that prehistoric subsistence strategies emerged from complex interactions between ecological constraints and cultural practices, including food processing and social organization.

ObjectivesAutosomal dominant hypocalcified amelogenesis imperfecta (ADHCAI; OMIM#130900) is a hereditary enamel defect caused by truncation mutations in FAM83H, though the underlying pathogenic mechanisms remain incompletely understood. This study aimed to identify novel FAM83H mutations in a Chinese family with ADHCAI and to investigate their functional consequences on enamel formation.Materials and methodsA three-generation ADHCAI family underwent clinical and genetic evaluation. Whole-exome sequencing and Sanger sequencing were used for mutation identification. The proband's enamel was analyzed by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Structural impacts of the mutation were predicted bioinformatically (PSIPRED, SWISS-MODEL). Patient-derived periodontal ligament cells (PDLCs) were assessed by Western blot, immunofluorescence, and quantitative real-time PCR for key enamel matrix proteins (AMELX, AMBN, ENAM) and osteogenic markers (RUNX2, ALP).ResultsA novel heterozygous nonsense mutation (c.1819G>T, p.(Glu607*)) in FAM83H was identified, resulting in a C-terminally truncated protein lacking 573 residues that mislocalizes from the cytoplasm to the nucleus. SEM-EDX revealed disorganized enamel ultrastructure, a reduced calcium-to-phosphorus ratio, and increased porosity. Functional analysis in PDLCs showed coordinated downregulation of enamel matrix proteins and osteogenic markers, indicating a dual regulatory role for FAM83H in biomineralization.ConclusionsOur findings are consistent with the "presecretory pathogenesis" model for ADHCAI, wherein nuclear-mislocalized truncated FAM83H may disrupt enamel mineralization partly through transcriptional suppression of matrix components. This expands the FAM83H mutational spectrum, offers preliminary mechanistic insight, and suggests potential targets for pre-eruptive therapeutic strategies.

ObjectivesTo evaluate the survival and success outcomes of teeth affected by external cervical resorption (ECR) managed using three distinct treatment strategies, with periapical radiographs and small field of view cone beam computed tomography used for diagnosis and treatment planning.Materials and methodsThis retrospective, multi-centre cohort study analysed 296 teeth diagnosed with ECR across five specialist endodontic practices between 2009 and 2024. Management approaches included periodic review (Treatment 1), external repair with or without endodontic intervention (Treatment 2), and internal repair (Treatment 3). Treatment selection was based on clinical and radiographic characteristics, including lesion accessibility, symptomatology, and the presence of bone-like tissue. Patients underwent annual clinical and radiographic review. The primary outcome was tooth survival; secondary outcomes included success (asymptomatic and healed) and failure (extraction due to progression or non-restorability). Kaplan-Meier survival estimates and Cox proportional hazards models were applied.ResultsA total of 296 teeth from 233 patients were followed for a mean of 2.9 years (range: 12-123 months). Estimated cumulative survival rates at 1, 2, 5, 7, and 10 years were 95.5%, 93.3%, 85.7%, 80.5%, and 80.5%, respectively. Multivariable analysis demonstrated that internal repair and higher Patel lesion classifications, particularly circumferential involvement greater than 180°, were associated with a higher extraction hazard. The Heithersay classification was not significantly associated with survival. Estimated cumulative survival rates were 93.6%, 90.2%, and 59.1% for Treatments 1, 2, and 3, respectively.ConclusionsHigher estimated survival was observed among teeth selected for periodic review, followed by external repair and internal repair. Greater three-dimensional lesion extent, > 180°, was associated with an increased extraction hazard. Treatment selection was influenced by lesion characteristics and clinical judgement; differences between treatment groups should be interpreted as associations rather than evidence of treatment superiority. External repair remained viable, whereas internal repair was associated with a greater risk of failure. The Patel (3D) classification was more strongly associated with survival outcomes than the Heithersay (2D) classification and supports detailed lesion characterization and treatment planning. Treatment decisions should be guided by lesion extent, accessibility, symptoms, and evidence of reparative activity. The findings represent associations observed within a retrospective cohort.