Insights into the aetiologies of hypercementosis: A systematic review and a scoring system

Finite element analysis of Neanderthal and early Homo sapiens maxillary central incisor

Neanderthal anterior teeth are very large and have a distinctive morphology characterized by robust 'shovel-shaped' crowns. These features are frequently seen as adaptive responses in dissipating heavy mechanical loads resulting from masticatory and non-masticatory activities. Although the long-standing debate surrounding this hypothesis has played a central role in paleoanthropology, is still unclear if Neanderthal anterior teeth can resist high mechanical loads or not. A novel way to answer this question is to use a multidisciplinary approach that considers together tooth architecture, dental wear and jaw movements. The aim of this study is to functionally reposition the teeth of Le Moustier 1 (a Neanderthal adolescent) and Qafzeh 9 (an early Homo sapiens adolescent) derived from wear facet mapping, occlusal fingerprint analysis and physical dental restoration methods. The restored dental arches are then used to perform finite element analysis on the left central maxillary incisor during edge-to-edge occlusion. The results show stress distribution differences between Le Moustier 1 and Qafzeh 9, with the former displaying higher tensile stress in enamel around the lingual fossa but lower concentration of stress in the lingual aspect of the root surface. These results seem to suggest that the presence of labial convexity, lingual tubercle and of a large root surface in Le Moustier 1 incisor helps in dissipating mechanical stress. The absence of these dental features in Qafzeh 9 is compensated by the presence of a thicker enamel, which helps in reducing the stress in the tooth crown.

Unraveling the Life History of Past Populations through Hypercementosis: Insights into Cementum Apposition Patterns and Possible Etiologies Using Micro-CT and Confocal Microscopy

The "teeth-as-tools" hypothesis posits that Neanderthals used their anterior teeth as a tool or a third hand for non-dietary purposes. These non- or para-masticatory activities (e.g., tool-making or food preparation prior to ingestion) have also been described in other past and extant human populations, and other Primates. Cementum is the mineralized tissue that covers the tooth root surface and anchors it to the alveolar bone. Under certain conditions (e.g., mechanical stress, infection), its production becomes excessive (i.e., beyond the physiological state) and is called 'hypercementosis'. Several studies in dental anthropology have established a correlation between the teeth-as-tools and hypercementosis. The present work aims to characterize the different patterns of cementum apposition on archeological teeth and discuss their supposed etiology. Using microtomography and confocal microscopy, the patterns of cementum apposition (i.e., thickness, location, and surface characteristics) were analyzed in 35 hypercementotic teeth (Sains-en-Gohelle, France; 7th-17th c. A.D.). Four groups were identified with distinct hypercementosis patterns: (1) impacted, (2) infected, (3) hypofunctional, and (4) hyperfunctional teeth. Characterizing hypercementosis can contribute to documenting the oral health status (paleopathology) and/or masticatory activity of individuals, even from isolated teeth. This has implications for the study of fossil hominins, particularly Neanderthals, known for their use of anterior teeth as tools and frequent and substantial occurrence of hypercementosis.

[Patterns of hypercementosis and their relationship with possible local etiological factors in radiographs of individuals from a mexican population]

Objective

Hypercementosis (HPC) is an asymptomatic pathology that, according to the existing literature, has a low prevalence, there is a lack of information and research on it, within these studies, few are made by ethnic groups. To determine the prevalence and radiographic patterns of this condition, as well as the analysis of the relationship of the pathology with some of what are considered possible local triggering factors (FDL) in Mexican individuals.

Methodology

1193 orthopantomographies (OPG) were analyzed, randomly selected from patients of both sexes, with a chronological age range between 18 and 90 years, identifying the prevalence of HPC, as well as its relationship between age groups, its morphological patterns (focal, diffuse and sleeve-shaped), its distribution by anatomical region and dental organs (ODs) and the association of its presence with possible local triggering factors.

Results

348 DO with HPC were found in a total of 194 patients (16.30%), with no relevant differences between genders (P> 0.05). There was a significant increase with respect to the presence of HPC in relation to the increase in the age of the patients (P= 0.001), finding it present in 10% of the age group <40 years, in 20.30% in the group of 40 to 60 years and > 60 in 30.20%. It was found more frequently in a diffuse form (75.28%), followed by the focal pattern (19.54%) and finding the sleeve-shaped morphology less common (5.17%). The mandible presented the greatest number of ODs with the presence of HPC, 136 (39.08%), with the left side being the most affected with 86 OD. The dental group with the greatest involvement was that of molars and premolars.

Conclusions

The prevalence of hypercementosis was 16.30% in the Mexican individuals evaluated. Its presence increases as the age of the patients advances. Its main location is the mandibular region with a predilection for premolars and molars. Even though the idiopathic origin is the most frequent, it was observed that dental impaction is a possible local triggering factor.