Tooth Morphology Research Articles

Evaluation of root and root canal morphology of mandibular and maxillary canine teeth in Turkish subpopulation by cone beam computed tomography with using two classification systems

BackgroundKnowledge of root and canal morphology is a prerequisite for effective nonsurgical and surgical endodontic treatments. The aim of this cone beam computed tomography (CBCT) study was to evaluate the root canal morphology of permanent canines in a Turkish subpopulation using two classification systems.MethodsA total of 2,000 canine teeth were examined. The number of roots was identified, and root canal configurations were classified according to Vertucci’s classification and a new system for classifying root and canal morphology. Fisher’s exact test was used for statistical analysis, and the level of significance was set at 0.05 (p = 0.05).ResultsThe canal configuration type I was the most common in all canines, while type III was the second most common. According to the new system, the code 1C1−1 was the most common, whilst 1C1 (A1) codes were the second most common for all canines. In this study, more than 10% morphology that did not fit the Vertucci classification was detected. In the categorization of accessory canals based on the new classification, the most common type in all canines was 1C1,1 (A1). Age had an effect only on the morphology of the left maxillary canine (p < 0.05).ConclusionCanines in the Turkish subpopulation showed a relatively high degree of variation in root and canal anatomical variations. Clinicians should be aware of where canals converge or diverge to avoid missing canals. The new system for classifying canal morphology describes root and canal configurations more accurately and practically compared to the Vertucci classification.

Allocation of Scattered Teeth From a Batavia 1629 Communal Grave

ABSTRACTWhen the Dutch ship Batavia wrecked in 1629 on Morning Reef in the Houtman Abrolhos Islands off the coast of Western Australia, most of the passengers and crew survived the wreck, but about 200 of the survivors later perished on and around Beacon Island where they had landed after the wreck. As many as 81 bodies may be buried on Beacon Island and 21 bodies have been excavated to date. During the 2017–2018 excavations, seven of the buried individuals were excavated from a communal grave. During the excavation, 18 teeth were found scattered in the soil around the bodies. A systematic method is presented to allocate isolated teeth to their appropriate skeleton using tooth morphology and tooth wear as the primary criteria for allocation. Tooth wear must be similar to the adjacent and opposing dentition before the tooth is considered for allocation. If the wear is similar, the tooth is gently fitted into the proposed tooth socket. The fit of the tooth in the tooth socket is visually assessed, and if close, the tooth is radiographed in situ to confirm the allocation. Each separated tooth must be tested in all the sites to which it is appropriate. If a tooth fits more than one site, it cannot be allocated. Use of this method allowed allocation of 10 separated teeth in 28 possible sites. The possible cause of the separation of teeth from the skeleton is discussed.

Dental Anomalies in the Past: Fusion, Gemination, and Talon Cusp in Two Archeological Samples.

Disruption in odontogenesis can influence the normal development of both deciduous and permanent dentition resulting in anomalies in morphology, number, and position of teeth. Although dental anomalies are frequently reported in clinical practice, their occurrence in past populations from archeological contexts is rarely acknowledged. To describe two cases of dental anomalies on two non-adult individuals from Italian archeological sites. Individual sex diagnosis was performed by analyzing amelogenin peptides from the dental enamel through liquid chromatography mass spectrometry (LC-MS/MS). Age-at-death estimation was based on stages of dental formation and eruption. Dental twinning and talon cusp were morphologically evaluated and classified following standardized scoring systems proposed by clinical literature. The first individual, a 3-4-year-old female from the Imperial Roman necropolis of Isola Sacra, presents the fusion of the upper right deciduous central incisor with a supplementary tooth; the second individual, a 3-3.5-year-old male from a Late Antiquity catacomb, shows a case of bilateral gemination on the upper permanent central incisors with a co-occurrence of dental gemination and talon cusp on the right one. The cases reported here (the two anomalies in the individuals presented) are useful into understanding these dental conditions within past/archaeological populations.

Metal Isotopes in Mammalian Tissues

Ecologists rely on a wealth of data, including field observations and light stable isotopes, to infer dietary preferences and other ecological and physiological properties in living mammals. But inferring such important traits (e.g., trophic position, metabolism, pathologies) in extinct animals, including humans, can be challenging because biological processes rarely mirror morphology as preserved in the fossil record. For instance, dietary behavior does not necessarily reflect tooth morphology. As an additional challenge, some isotopic mammal tissues commonly used in modern ecology, such as collagen in bone or dentin or keratin from hair, hoof, or horn, do not generally preserve in fossil remains older than ∼200 kyr. In contrast, major constituents of bioapatite often retain their initial isotopic composition through fossilization processes. Recent analytical developments in mass spectrometry now allow, using small samples, for assessment of isotopic variability of major and trace elements such as calcium or zinc. Here, we review the application potentials of metal (nontraditional isotopes) for (paleo)ecological, (paleo)physiological, and (paleo)mobility inferences as applied to mammalian research. ▪ Mammals are key elements of modern ecosystems and possess a rich evolutionary history, yet inferences about their past ecologies and physiologies are challenging to retrieve using traditional geochemical toolkits. ▪ Metal stable isotopes provide a novel and complementary approach to unveil paleoecological and paleophysiological characteristics of extinct mammal species. ▪ Within a 20-year time frame, the core of metal isotopic data in mammalian research remains small compared to traditional isotopic systems (C, O, N), which is inviting for designing cost-effective instrumentation and increasing dissemination across scientific disciplines.

Prevalence, Occurrence, and Characteristics of Supernumerary Teeth Among the Saudi Arabian Population Using Panoramic Radiographs.

Supernumerary teeth numerical anomalies and the early diagnosis of supernumerary teeth is very important to avoid potential complications. The study aim was to determine the prevalence, occurrence, and characteristics of supernumerary teeth among the Arabian population. A retrospective radiographic study was performed using panoramic radiographs of patients attending a teaching hospital from January 2018 to December 2020. Only healthy patients with clear radiographs were included in the study, and patients with syndromes, cleft lip, and palate, and unclear radiographs were excluded from the study. The details include the patient's age and gender, supernumerary tooth number, location, orientation, and position. Only a single examiner was involved in the data collection and analysis. Overall, 38 (2%) patients were observed with 47 supernumerary teeth. Among them, 76% were males and 24% were females, with a mean age of 16.1 ± 9.7 years. Mesiodens (87%) are the common type of supernumerary tooth, and the majority of the supernumerary teeth were impacted (66%). The majority of the patients presented with a single supernumerary tooth, while 24% of the patients presented with two supernumerary teeth. Sixty percent of the supernumerary teeth were conical in morphology, followed by a tuberculate morphology. In the study population, most of the supernumerary teeth were normal in orientation. The prevalence of supernumerary teeth was 2%. Among them, the majority were observed at the anterior region of the maxillary arch with a conical shape of normal orientation. The gender-based comparison of location, orientation, morphology, eruption, and number of supernumerary teeth showed male predilection.

Metalloproteinases are involved in the regulation of prenatal tooth morphogenesis.

During development, tooth germs undergo various morphological changes resulting from interactions between the oral epithelium and ectomesenchyme. These processes are influenced by the extracellular matrix, the composition of which, along with cell adhesion and signalling, is regulated by metalloproteinases. Notably, these include matrix metalloproteinases (MMPs), a disintegrin and metalloproteinases (ADAMs), and a disintegrin and metalloproteinases with thrombospondin motifs (ADAMTSs). Our analysis of previously published scRNAseq datasets highlights that these metalloproteinases show dynamic expression patterns during tooth development, with expression in a wide range of cell types, suggesting multiple roles in tooth morphogenesis. To investigate this, Marimastat, a broad-spectrum inhibitor of MMPs, ADAMs, and ADAMTSs, was applied to ex-vivo cultures of mouse molar tooth germs. The treated samples exhibited significant changes in tooth germ size and morphology, including an overall reduction in size and an inversion of the typical bell shape. The cervical loop failed to extend, and the central area of the inner enamel epithelium protruded. Marimastat treatment also disrupted proliferation, cell polarization and organization compared to control tooth germs. Additionally, a decrease in laminin expression was observed, leading to a disruption in continuity of the basement membrane at the epithelial-mesenchymal junction. Elevated Hif-1α expression correlated with a disruption to blood vessel development around the tooth germs. These results reveal the crucial role of metalloproteinases in tooth growth, shape, cervical loop elongation, and the regulation of blood vessel formation during prenatal tooth development.

A new procolophonid with complex dentition from the Late Triassic of southwest England

AbstractFissure fill deposits from the Late Triassic to Early Jurassic of England and Wales preserve a diverse small tetrapod fauna including procolophonids, an important group of Permian and Triassic parareptiles that radiated across Pangaea following the end‐Permian extinction event. Procolophonids are currently known from two fissure fill sites: incomplete and isolated remains from Ruthin Quarry (Wales) and type and referred material of Hwiccewyrm trispiculum from Cromhall Quarry (southwest England). The age of the Cromhall fissure deposits has been debated but recent radiometric dating suggests a Carnian age for at least some of the fossil assemblages. Here, we present material from several fissure assemblages at Cromhall, which are interpreted as stratigraphically older than the assemblage that yielded Hwiccewyrm. We describe a new species of leptopleuronine procolophonid based on partial remains with unique tooth morphology. Threordatoth chasmatos gen. et sp. nov. is characterized by maxillae with a reduced number of complex tricuspid teeth along with dentaries that bear labiolingually compressed monocuspid teeth and in some cases have a peculiar edentulous tip. These distinct tooth morphologies occlude closely, perhaps facilitated by a flexible dentary symphyseal connection. This unique combination of characters may suggest a high degree of oral food processing of a mode unlike other procolophonids, occurring among the broader leptopleuronine adaptation towards diets of high‐fibre herbivory/omnivory and insectivory. Phylogenetic analysis places the remains of Threordatoth as a derived leptopleuronine, sister taxon to Hwiccewyrm, in a clade with taxa including Soturnia, Hypsognathus, Libognathus and two unnamed leptopleuronines from the southwest USA.

New material of the small raoellid artiodactyl Metkatius kashmiriensis Kumar and Sahni, 1985 (Mammalia) from the middle Eocene of the Kalakot area, Rajouri District, Jammu and Kashmir, India

New material of the small raoellid artiodactyl Metkatius kashmiriensis is reported from the middle Eocene of the Upper Subathu Formation in the Kalakot area, Jammu and Kashmir, northwest Himalaya, India. The fossil material consists of numerous mandibular and maxillary fragments and isolated teeth, mainly belonging to juvenile specimens. It documents the poorly known dental morphology of M. kashmiriensis and provides an overview of its intraspecific variation, allowing to redefine its diagnosis. M. kashmiriensis is characterized by a particularly small size compared with other raoellid species, and by bunodont molars with moderately marked transverse lophs. The M/1-2 are much longer than wide and display characters similar to those of Rajouria gunnelli, such as the presence of a small paraconid and a mesial mesiostylid. The P/4 bears distally a small hypoconid, which appears to be unique in Raoellidae. The description of the new material also allows to document the poorly known morphology of the deciduous teeth of raoellids. The DP2/ is reported for the first time, and the DP/4 of M. kashmiriensis shows a morphology different from that of Indohyus, with the absence of mesial basin anterior to the paraconid and the primoconid. Contrary to what has recently been proposed, these results confirm that M. kashmiriensis is a valid species and not a synonym of Indohyus indirae, and highlight the great morphological diversity present within the Raoellidae during the middle Eocene in the Indian subcontinent.

Research on the method of digital technology assisted direct resin composite restoration for deep distal caries in mandibular second molars

Objective: To explore the digital design and fabrication technology of personalized restorative matrix for dental filling, and to explore the feasibility of direct resin restoration for deep caries lesions in distal neck of mandibular second molar. Methods: For patients with deep caries lesions in the distal neck of the mandibular second molar who visited the Department of Cariology and Endodontology of Peking University School and Hospital of Stomatology from September 2023 to April 2024, after preparing the cavity and gingival retractor, a three-dimensional intraoral scanner was used to obtain three-dimensional data of the patient's dentition. In the dental restoration computer-aided design software, the inlay function was used to generate the restored tooth morphology. The edge range of the personalized restorative matrix was drawn on the restored model by three-dimensional reverse engineering software to achieve edge sealing effect. The selected edge range data was processed with distal shelling to generate a digital model of a personalized restorative matrix with a thickness of 0.5 mm. A metal three-dimensional printer was used to fabricate the titanium alloy restorative matrix, and its application was completed in 10 clinical cases. The marginal adaptation and retention stability of the personalized restorative matrix were evaluated under a dental microscope, and forming effect evaluation was performed through immediate postoperative periapical radiographs. Results: The preliminary clinical application of the personalized restorative matrix fabricated using digital technology revealed that, in the treatment of 10 affected teeth, rubber dam isolation was successfully ensured, resulting in clinically effective direct resin composite restorations with optimal marginal adaptation and reasonable contours. Immediate postoperative periapical radiographs showed good convexity of the filling body, with no overhangs found. Both marginal adaptation and retention stability met the requirements of clinical treatment. Conclusions: The personalized restorative matrix designed in this study can solve the clinical problems of moisture separation and resin forming in the treatment of deep caries lesions in distal neck of the mandibular second molar, and can achieve stable and reliable adhesive restoration effects.

Fully automated method for three-dimensional segmentation and fine classification of mixed dentition in cone-beam computed tomography using deep learning

ObjectiveTo establish a high-precision, automated model using deep learning for the fine classification and three-dimensional (3D) segmentation of mixed dentition in cone-beam computed tomography (CBCT) images. MethodsA high-precision, automated deep learning model was built based on modified nnU-Net and U-Net networks and was used to classify and segment mixed dentition. It was trained on a series of 336 CBCT scans and tested using 120 mixed dentition CBCT scans from three centers and 143 permanent dentition CBCT scans from a public dataset. The diagnostic performance of the model was assessed and compared with those of two observers with different seniority levels. ResultsThe model achieved accurate classification and segmentation of specific tooth positions in the internal and external mixed dentition datasets (Dice similarity coefficient: 0.964 vs. 0.951; Jaccard coefficient: 0.931 vs. 0.921; precision: 0.963 vs. 0.945; recall: 0.945 vs. 0.941; F-1 score: 0.954 vs. 0.943). These indices consistently exceeded 0.9 across multiple conditions, including fillings, malocclusion, and supernumerary tooth, with an average symmetric surface distance of 0.091 ± 0.029 mm. For permanent dentition, the Dice similarity and Jaccard coefficients exceeded 0.90, the average symmetric surface distance was 0.190 ± 0.092 mm, and precision and recall exceeded 0.94. With the aid of the model, the performance of junior dentists in mixed dentition classification and segmentation improved significantly; in contrast, there was no significant improvement in the performance of senior dentists. The speed of segmentation conducted by the dentists increased by 20.9–22.8 times. ConclusionThe artificial intelligence model has strong clinical applicability, robustness, and generalizability for mixed and permanent dentition. Clinical significanceThe precise classification and 3D segmentation of mixed dentition in dentofacial deformities, supernumerary teeth, and metal artifacts present challenges. This study developed a deep learning approach to analyze CBCT scans, enhancing diagnostic accuracy and efficacy. It facilitates detailed measurements of tooth morphology and movement as well as informed orthodontic planning and orthotic design. Additionally, this method supports dental education by assisting doctors in explaining CBCT images to the families of pediatric patients.

The last piece of the puzzle, the DP4 of Cephalomys arcidens (Rodentia, Caviomorpha) from the late Oligocene of Patagonia (Argentina)

ABSTRACT Deciduous dentition of extinct mammals has traditionally received little attention based on its poor representation in the fossil record. However, several aspects related to this tooth locus could have important evolutionary significance (time of replacement, retention throughout life, and morphology). In this work, we described a new specimen from late Oligocene levels of Cabeza Blanca (Chubut Province, Argentina). This fossil corresponds to a maxillary fragment with a deciduous premolar (DP4) assigned herein to Cephalomys arcidens based on morphological characteristics, size, and comparisons with other late Oligocene-Early Miocene caviomorphs. It can be identified as a DP4 due to its mesiodistally longer than wide diameter, shallow flexi, complex tooth morphology, and its position in the maxillary fragment. This is the first description of the DP4 of a Cephalomyidae and the last unknown dental locus of Cephalomys arcidens. Now, C. arcidens is one of the better-known late Oligocene caviomorphs since it is recognised through the complete dentition, crania, and mandibles. In addition, this new information would be used to evaluate the importance of deciduous dentition in resolving phylogenetic relationships in the enigmatic cephalomyids in particular and in Caviomorpha in general.

Root and Canal Morphology of Maxillary Incisors Teeth in a Sample of Yemeni Population Using Two Classification Systems: A CBCT Study

Objective: To determine the root and canal morphology of permanent maxillary central and lateral incisors in a sample of Yemeni population using cone-beam computed tomography (CBCT). Materials and Methods: A retrospective CBCT analysis of 400 maxillary anterior teeth from a Yemeni adults (18-50 years) was conducted. Image evaluation in sagittal, axial, and coronal planes using Ez3D-i software assessed root number, canal orifice number, canal number, and canal configuration based on Vertucci's and Ahmed's classifications. Descriptive statistics and Chi-square test were employed (p &lt; 0.05). Results: All incisors exhibited a single root and canal with a single orifice. The predominant canal configuration was Type 1 according to both Vertucci's (93.5%) and Ahmed's (93.8%) classifications. Type 5 (bifurcation at the apex) was observed in 6.25% (Vertucci) and 6.0% (Ahmed) of cases, while Type 3 (canal division and reunion) was rare (0.25% Vertucci, 0.2% Ahmed). Conclusion: Permanent maxillary central and lateral incisors in the Yemeni population primarily demonstrate a single root and canal. Although variations in canal configuration exist, they are infrequent.

Obruchevodid petalodonts (Chondrichthyes, Holocephali) from the Upper Mississippian (Serpukhovian) Bangor Limestone of northern Alabama, U.S.A.

ABSTRACT Undocumented collections and new field studies have revealed a diverse chondrichthyan assemblage within the Upper Mississippian (Serpukhovian/middle-upper Chesterian) Bangor Limestone in northern Alabama, U.S.A. which includes multiple new occurrences of holocephalians. Included in these new records are the first occurrences of Obruchevodidae (Euchondrocephalii, Petalodontiformes) outside of the synchronic Bear Gulch Limestone Member of the Heath Formation in Montana, U.S.A. Isolated teeth from Fissodopsis robustus and Netsepoye hawesi represent the first specimens to provide three-dimensional tooth morphology that is otherwise obscured in the holotypes. Additionally, these specimens represent the first reported occurrences from the southern coast of the subcontinent Laurentia. The significance of these new specimens is discussed in regard to the comparative morphology of Petalodontiformes and the paleobiogeography of Obruchevodidae.

In Vitro Comparison of Direct Attachment Shape and Size on the Orthodontic Forces and Moments Generated by Thermoplastic Aligners During Expansion.

To evaluate the effects of varying direct attachment shape and size on the forces and moments generated by thermoplastic aligners during simulated expansion. An invitro orthodontic force tester (OFT) was used to measure the forces and moments from a typodont where the buccal teeth were translated lingually 0.2 mm to simulate expansion. Hemi-ellipsoid and rectangular attachments with either 0.5 or 1.0 mm thickness were added on upper right first premolar (UR4), second premolar (UR5) and first molar (UR6). Analysis of variance (ANOVA) was used to determine two-way interactions among the factors on the outcomes. The interactions between group and tooth were significant for all outcomes (p < 0.001). The greatest buccal forces (Fy) were observed with 1 mm rectangular attachment on the UR4 (0.78 ± 0.29 N), with 1 mm hemi-ellipsoid attachment on UR5 (0.28 ± 0.21 N) and with 0.5 mm rectangular attachment on UR6 (1.71 ± 0.18 N). The greatest buccolingual moments (Mx) were obtained with 1 mm rectangular attachment on UR4 (5.61 ± 1.43 Nmm), without any attachments on UR5 (3.33 ± 1.73 Nmm) and with 1 mm hemi-ellipsoid attachment on UR6 (4.18 ± 4.31). Direct attachment shape and size had a significant effect on the orthodontic forces and moments generated by thermoplastic aligners during simulated expansion. Although loads varied significantly by tooth morphology and its location in the arch, best forces and moments for expansion were obtained with 1 mm rectangular attachments on UR4s, 1 mm hemi-ellipsoid attachments on UR5s and 0.5 mm rectangular attachments on UR6s.

Gender Determination Through Dental Morphology: A Cross-Sectional Study.

Microesthetics portrays the tooth morphology, shape, size, shade, and color. The debate of whether microesthetics may or may not be related to gender is the main focus or interest of our study. The aim of our study is to assess if dentists are able to identify the gender of the patient by evaluating the dental morphology using intraoral photographs only (retracted lips and cheeks). This study was a retrospective cross-sectional survey among general dentists and dental specialists practicing in Kuwait. A sample of 151 participants was approached through a multi-stage random sampling method. Data were collected through personal visits to each of the public dental centers. Of these 151 selected, a sample of 10 participants was randomly selected to repeat their participation and answer the questionnaire a second time 2 months after their initial partaking. The statistical analysis for the study was conducted using chi-square tests of goodness of fit and Pearson chi-square. The objectives of this were to compare the dentists' current performance to the task to see if it was due to chance, to compare their previous performance to chance, and to compare their previous and current performances using the McNemar test to determine if any significant differences existed. In our study, tooth morphology was linked to gender significantly by the participants, which showed that despite some differences, it may still be identified. However, orthodontists did not perform significantly better than other specialties. In conclusion, our study showed that dentists are able to identify or determine gender based on photographs, which is inconsistent with our starting hypothesis. Overall, the study's findings suggest that both orthodontists and dentists from other specialties could identify an individual's gender based on smiling photographs.

Three-dimensional assessment of root canal morphology of primary dentition using cone beam computed tomography.

Root canal therapy in primary teeth is exceedingly complex due to the unique internal geometry of the pulp cavity. The purpose of this study was to evaluate variations in primary teeth root canal morphology and applicability of the Ahmed etal. (Int Endod J, 50, 2017, 761) alphanumeric system for classifying them. A retrospective analysis of 2024 primary teeth from an existing CBCT database was performed for assessing variations in root canal morphology. Descriptive statistics and the chi-squared test were used for data analysis. The maxillary canines exhibited splitting levels of 5.9% (right) and 6.6% (left), and merging levels of 1% (both sides); maxillary lateral incisors showed splitting levels of 2.6% (right) and 0.8% (left), with no merging observed; mandibular second molars had splitting levels of 1.5% (right) and 0.8% (left), with no merging observed; and mandibular lateral incisors exhibited a merging level of 0.9% (right), with no splitting observed. This study provides new insights into the variations in root canal morphology of primary teeth, particularly highlighting the variations found in primary canines. The Ahmed etal. (Int Endod J, 50, 2017, 761) classification system was found to be a useful tool for categorizing these variations.

Long‐term injury records reveal the role of biting in male–male combat in the Japanese giant salamander

Abstract Biting is a common male–male combat tactic across jawed vertebrates, in which teeth or bony beaks serve as weapons. Because biting can cause severe injuries in some species, bite scars provide critical information about the degrees and patterns of fights. Amphibians have a remarkable diversity in tooth morphology and arrangement. However, the functional ecology of amphibian teeth is poorly studied. For example, unlike aquatic suction‐feeding frogs that lost teeth, aquatic salamanders that suction‐feed prey retain numerous sharp teeth, suggesting that teeth as weapons may partially explain their retention. Here, we analysed long‐term injury records of one of the fully aquatic, suction‐feeding salamanders (Japanese Giant Salamander, Andrias japonicus) to examine the previously unexplored potential of amphibian teeth as weapons for male–male combat. The majority of the injuries were missing toes and limbs, which most likely occurred during intra‐specific combat. We explored associations between injuries and independent variables such as sex, body size, body condition and stream sections. We also investigated possible injury‐pattern biases along the lateral (i.e. right vs. left) and longitudinal (i.e. anterior vs. posterior) axes, which could reveal how these animals fight. We found that males had more injuries, larger individuals had more injuries, and males with poorer conditions had more injuries. There was no association between injuries and stream sections. In addition, we found that salamanders had more injuries on the right and posterior sides of the body. The lateral asymmetry in injuries is likely associated with turning asymmetry during combat. Our results revealed the intense male–male combats of giant salamanders, providing evidence of the use of teeth as weapons. Combats via biting in amphibians may be much more common and severe than currently known. Our research suggests the function of amphibian teeth as weapons, which is likely to be a vital selective agent shaping its remarkable diversity.

Impact of vertical facial type on alveolar bone thickness and tooth morphology: A retrospective CBCT-based clinical study

IntroductionThe relationship between vertical facial patterns and the morphology of the alveolar bone and teeth is crucial for successful orthodontic treatment planning. This study aimed to evaluate the relationship between vertical facial patterns, bone thickness, and root-crown dimensions in the maxillary anterior teeth. MethodsThis retrospective study screened 300 cone-beam computed tomography (CBCT) scans of orthodontic patients between December 2022 and November 2023, with 115 meeting the inclusion criteria. Buccal and lingual alveolar bone thickness, along with crown and root lengths of maxillary anterior teeth, were measured and compared across short, normal, and long facial types, classified according to the Frankfort-Mandibular Plane Angle. One-way ANOVA, independent-samples Kruskal-Wallis, and post-hoc tests were used for statistical analysis. ResultsSignificant differences in alveolar bone thickness were observed across facial types, with short facial types showing consistently greater thickness in the apical and mid-palatal regions compared to normal and long facial types (p < 0.05). No significant differences in crown or root lengths were found among the facial types. ConclusionFacial type significantly influences alveolar bone thickness, particularly in short facial types, which demonstrate greater bone support. These findings underscore the importance of considering facial type in orthodontic treatment planning to minimize complications.

New insights into Tibetodus gyrodoides Young &amp;amp; Liu, 1954 (Actinopterygii, Pycnodontiformes) from the Qinghai-Xizang Plateau based on micro-CT data

The Pycnodontiformes is a distinctive group of fossil actinopterygian (ray-finned) fishes from the Late Triassic to Palaeogene. Tibetodus gyrodoides, reported in 1954, represents the only known fossil record of this group in China, holding significant scientific and historical importance. In this study, non-destructive techniques such as scanning electron microscopy (SEM) and micro-computed tomography (micro-CT) were utilised to reexamine the specimen, providing new insights into both the surface morphology and internal structures of the vomer and its teeth and investigating the process of tooth wear. A tooth covered by matrix was also discovered. Furthermore, an Elliptical Fourier Analysis (EFA) was conducted to quantitatively analyse the morphology of the palatal teeth in this specimen, adding new data for future research on pycnodontiforms and their feeding behavior.

PERMANENT MANDIBULAR CANINE WITH TWO ROOTS AND TWO CANALS

Mandibular canines are documented as frequently having one root and one canal in most cases, although around 15% may have two canals and two roots. Thus, anatomic variation exists therefore knowledge and keen observation during root canal can help to identify the less frequent variation morphology of tooth and play a pivotal role in the success of root canal treatment. This case report discusses a mandibular canine with two roots and two canals.