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1.
BMC Oral Health ; 24(1): 436, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38600486

RESUMEN

The anatomy of furcation favours the bacterial retention and makes periodontal debridement as well as oral hygiene procedures difficult. Teeth that have lost attachment to a level of the furcation are said to have a furcal invasion or furcation involved.Involvement of furcation in a multi-rooted tooth poses a very different type of clinical situation in terms of establishment of diagnosis, determination of prognosis and of course planning the treatment modality.The present study was carried out on 200 selected extracted human first and second permanent molar teeth based on a predefined criteria. Teeth with prosthetic crowns, fused or fractured roots, those not fully developed, grossly carious or heavily restored at the cementoenamel junction (CEJ) were excluded from the study. The morphology of the root trunk was recorded by measuring various dimensions of the root trunk,including furcal angle and root trunk volume was calculated by using a custom made special apparatus. The furcation areas were debrided with different types of curettes in the market in order to see how best the instrument could be maneuvered in the furcation area. The data so obtained was statistically analysed using SPSS version 22. The highest root trunk volume and the longest root trunk length were found to be in the maxillary second molar. 48.60% furcations didn't allow instrument engagementof furcation area with standard area specific curettes. The proposal of inclusion of root trunk length (mm) is suggested in addition to classification of FI to have assess prognosis and appropriate treatment for of the involved tooth.


Asunto(s)
Defectos de Furcación , Raíz del Diente , Humanos , Raíz del Diente/anatomía & histología , Diente Molar/cirugía , Diente Molar/anatomía & histología , Cuello del Diente , Pronóstico , Biometría , Defectos de Furcación/cirugía , Defectos de Furcación/diagnóstico
2.
Nature ; 628(8008): 569-575, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38570681

RESUMEN

Shuotheriids are Jurassic mammaliaforms that possess pseudotribosphenic teeth in which a pseudotalonid is anterior to the trigonid in the lower molar, contrasting with the tribosphenic pattern of therian mammals (placentals, marsupials and kin) in which the talonid is posterior to the trigonid1-4. The origin of the pseudotribosphenic teeth remains unclear, obscuring our perception of shuotheriid affinities and the early evolution of mammaliaforms1,5-9. Here we report a new Jurassic shuotheriid represented by two skeletal specimens. Their complete pseudotribosphenic dentitions allow reidentification of dental structures using serial homology and the tooth occlusal relationship. Contrary to the conventional view1,2,6,10,11, our findings show that dental structures of shuotheriids can be homologized to those of docodontans and partly support homologous statements for some dental structures between docodontans and other mammaliaforms6,12. The phylogenetic analysis based on new evidence removes shuotheriids from the tribosphenic ausktribosphenids (including monotremes) and clusters them with docodontans to form a new clade, Docodontiformes, that is characterized by pseudotribosphenic features. In the phylogeny, docodontiforms and 'holotherians' (Kuehneotherium, monotremes and therians)13 evolve independently from a Morganucodon-like ancestor with triconodont molars by labio-lingual widening their posterior teeth for more efficient food processing. The pseudotribosphenic pattern passed a cusp semitriangulation stage9, whereas the tribosphenic pattern and its precursor went through a stage of cusp triangulation. The two different processes resulted in complex tooth structures and occlusal patterns that elucidate the earliest diversification of mammaliaforms.


Asunto(s)
Evolución Biológica , Fósiles , Mamíferos , Diente , Animales , Euterios/anatomía & histología , Mamíferos/anatomía & histología , Mamíferos/clasificación , Mamíferos/fisiología , Marsupiales/anatomía & histología , Diente Molar/anatomía & histología , Diente Molar/fisiología , Filogenia , Diente/anatomía & histología , Diente/fisiología , Masticación
3.
J Dent ; 144: 104969, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38537881

RESUMEN

OBJECTIVES: Natural teeth and dental restorations present with various shades and levels of translucency. This study aimed to determine whether these variations in ceramic crowns and scan powder application affect the trueness of intraoral scanners. METHODS: Eight identical premade resin typodonts, each prepared for a crown on the maxillary right second molar, were used. Eight lithium disilicate crowns, distinguished by two levels of translucency (high and low) and four shades (BL1, A2, A3, and A4), were fabricated to an identical design and cemented onto each typodont, providing eight distinct experimental groups (2 levels of translucency × 4 shades). Reference scans were acquired using a desktop scanner. Test scans were performed ten times for each experimental group using two different intraoral scanners (Medit i700 and CEREC Primescan AC), with and without the application of scan powder (n = 10). Three-dimensional metrology software was used to assess the trueness of the intraoral scan datasets. Statistical analysis involved the Kruskal-Wallis H test, Mann-Whitney U test, and independent t-test (α=0.05). RESULTS: For powder-free intraoral scan datasets, the crown shade did not significantly affect trueness within each translucency group (P = 1.000). For both intraoral scanners, compared with low translucency groups, higher marked deviations were exhibited by high translucency groups (P<.001). Scan powder use largely mitigated these differences (P>.05) and enhanced the trueness of the intraoral scan (P<.01). CONCLUSIONS: Shade did not significantly influence the trueness of intraoral scans. High-translucency crowns were scanned with less accuracy than were low-translucency crowns. CLINICAL SIGNIFICANCE: Unlike tooth shade, translucency significantly affected the accuracy of intraoral scans. Therefore, considering the use of scan powder when scanning objects with high translucency may be beneficial.


Asunto(s)
Diseño Asistido por Computadora , Coronas , Porcelana Dental , Diseño de Prótesis Dental , Polvos , Humanos , Porcelana Dental/química , Color , Coloración de Prótesis , Imagenología Tridimensional/métodos , Cerámica , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología , Procesamiento de Imagen Asistido por Computador/métodos
4.
PLoS One ; 19(2): e0299123, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38394283

RESUMEN

INTRODUCTION: Understanding the anatomy of root canal systems and being aware of their variations is crucial for successful endodontic treatment. Specifically, the intricate and diverse nature of the root anatomy in maxillary third molars poses a significant challenge for dental clinicians. The study analyzed the morphology of the root canal system in maxillary third molars among residents of the Lower Silesia region in Poland using cone beam computed tomography (CBCT). MATERIAL AND METHODS: This retrospective cross-sectional imaging study was conducted at the X-Ray Diagnostics Laboratory of the Academic Dental Polyclinic of Wroclaw Medical University, Poland. The study evaluated 316 CBCT scans and included 196 maxillary third molars. They were obtained from 118 females and 78 males over the age of 18, in the period from January to April 2022 (three consecutive months). The number of roots, root canals, and root canal configurations according to Vertucci's classification were analyzed. RESULTS: Three-rooted maxillary molars were found most often (64.29%), followed by single-rooted (24.49%), two-rooted (7.65%), and four-rooted (3.57%) teeth. Among all the roots examined, Vertucci Type I root canals were the most prevalent. Our research found that single-rooted forms (40 teeth, 33.89% vs. 8 teeth, 10.26%, p = 0.0013) of maxillary third molars were significantly more common in females than in males. However, three-rooted forms (62 teeth, 79.49% vs. 64 teeth, 54.24%, p = 0.0013) of maxillary third molars were significantly more common in males than in females. DISCUSSION: In the Lower Silesia region, the typical maxillary third molar in the Polish population has a three-rooted structure with Vertucci Type I root canal configuration. We noted a sex-dependent correlation in maxillary third molar morphology, with single-rooted forms more prevalent in women and three-rooted forms in men.


Asunto(s)
Tercer Molar , Raíz del Diente , Masculino , Humanos , Femenino , Adulto , Persona de Mediana Edad , Tercer Molar/diagnóstico por imagen , Estudios Retrospectivos , Raíz del Diente/diagnóstico por imagen , Raíz del Diente/anatomía & histología , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología , Tomografía Computarizada de Haz Cónico/métodos , Cavidad Pulpar/diagnóstico por imagen
5.
Beijing Da Xue Xue Bao Yi Xue Ban ; 56(1): 190-195, 2024 Feb 18.
Artículo en Chino | MEDLINE | ID: mdl-38318917

RESUMEN

Maxillary molar with three roots and 3 to 4 canals is a common occurrence. However, in addition to common root canal anatomy, there may be significant differences in the number, distribution, and morphological structure of root canals. The success of root canal treatment is dependent on ensuring that all the intricate details associated with it are meticulously followed. Failure to locate all canals could have a negative effect on the treatment as it may lead to initiation or continuation of periapical pathology. Missed canals were the main reason for patients reporting back for nonsurgical root canal retreatment. Moreover, the bacteria residing in such canals could also result in persistence of symptoms. Root canal anatomy is complex, and the recognition of anatomic variations could be a challenge for clinicians. This article presents three cases of endodontic management of maxillary molars with atypical canal morphology. In the three cases of this study, the patients underwent cone beam computed tomographic (CBCT) examination before root canal treatment. The CBCT images revealed that the maxillary molars in case 1 and case 2 had 5 canals. Case 1: 2 mesiobuccal (MB, MB2), two distobuccal (DB and DB2), and one palatal canal. Case 2: 2 mesiobuccal (MB, MB2), one distobuccal (DB), and two palatal canals (MP and DP). In case 3, CBCT scan slices showed that the maxillary first molar presented as a C-shaped root canal with a rare tooth anomaly of taurodontism. Although C-shaped root canals were most frequently seen in the mandibular second molar, they might also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. Case 3 described the fusion between mesiobuccal and palatal roots of the maxillary first molar, forming a C-shaped mesiopalatal root canal. The above cases suggest that endodontists should always be aware of aberrancies in root canal system apart from the knowledge of normal root canal anatomy. CBCT as a means of diagnosis can be helpful for identifying and managing these complex root canal systems. This case series also highlights the importance of magnification and illumination. Through using an endodontic microscope, clinicians can identify root canals that are difficult to locate or overlooked with normal vision. A correct access opening is a most important step to locate and negotiate the orifices of root canals. The use of ultrasonic tips can refine the access cavity and allow controlled and delicate removal of calcifications and other interferences to the canal orifices, thereby helping to locate the extra orifices.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Diente Molar , Humanos , Tomografía Computarizada de Haz Cónico/métodos , Diente Molar/anatomía & histología , Tratamiento del Conducto Radicular/métodos , Tomografía Computarizada por Rayos X , Raíz del Diente/diagnóstico por imagen , Cavidad Pulpar/diagnóstico por imagen , Maxilar
6.
Int. j. morphol ; 42(1): 28-34, feb. 2024. ilus, tab
Artículo en Inglés | LILACS | ID: biblio-1528823

RESUMEN

SUMMARY: This work investigated the morphology of the root canal system of the mandibular first molar in a Malaysian subpopulation. Using micro-computed tomography with an isotropic resolution of 22 µm, 140 mandibular first molars were scanned. MIMICS software was used for segmentation, 3-D reconstruction and analysis of the acquired images. The canal configuration was described using Vertucci [supported by the supplementary configurations proposed by Sert & Bayirli (2004)] and Ahmed et al. (2027), coding systems. The chi-square test was used to assess the association between qualitative variables. By non-considering intercanal communications, Vertucci types IV (17.1%) and I (76.4%) were the most frequently reported configurations in the mesial and distal roots, respectively. Of the reported configurations, 24.3% and 4.3% were non-classifiable by Vertucci system in the mesial and distal roots, respectively. Up to 63.6% and 9.3% of the reported configurations were non- classifiable, and type I was the most frequent when considering intercanal communications (7.1% and 76.4% in the mesial and distal roots, respectively). According to Ahmed et al., system, almost half of the sample had more than four digits (47.9%), followed by the 3-digits category (20.71%). In both systems, a significant association was found between the canal configuration and the root type (p<0.001). The mandibular first molar of this Malaysian subpopulation demonstrated a wide range of root canal morphology. When compared to the Vertucci system, the system developed by Ahmed et al., successfully classified all molars configurations despite their level of complexity. The complex canal anatomy of mandibular first molars in this subpopulation warrants special attention during root canal treatment procedures.


En este trabajo se investigó la morfología del sistema de conductos radiculares del primer molar mandibular en una subpoblación de Malasia. Utilizando tomografía microcomputada con una resolución isotrópica de 22 µm, se escanearon 140 primeros molares mandibulares. Se utilizó el software MIMICS para segmentar (enmascarar), reconstruir en 3D, visualizar y analizar las imágenes adquiridas. La configuración del canal se describió utilizando Vertucci respaldado por las configuraciones complementarias propuestas por Sert & Bayirli (2004)] y Ahmed et al. (2017, 2020), sistemas de codificación. Se utilizó la prueba de chi-cuadrado para evaluar la asociación entre variables cualitativas. Sin considerar las comunicaciones intercanales, los tipos Vertucci IV (17,1%) y I (76,4%) fueron las configuraciones reportadas con mayor frecuencia en las raíces mesiales y distales, respectivamente. De las configuraciones reportadas, el 24,3 % y el 4,3 % fueron no clasificables por el sistema de Vertucci en las raíces mesial y distal, respectivamente. Hasta el 63,6 % y el 9,3 % de las configuraciones reportadas fueron no clasificables, siendo la tipo I la más frecuente al considerar las comunicaciones intercanales (7,1 % y 76,4 % en las raíces mesiales y distales, respectivamente). Según Ahmed et al. (2017, 2020) en el sistema, casi la mitad de la muestra tenía más de cuatro dígitos (47,9 %), seguido por la categoría de 3 dígitos (20,71 %). En ambos sistemas se encontró una asociación significativa entre la configuración del canal y el tipo de raíz (p<0,001). El primer molar mandibular de esta subpoblación de Malasia demostró una amplia gama morfológica del conducto radicular. En comparación con el sistema Vertucci, el sistema desarrollado por Ahmed et al. (2017, 2020) clasificaron con éxito todas las configuraciones de los molares a pesar de su nivel de complejidad. La compleja anatomía del canal de los primeros molares mandibulares en esta subpoblación merece una atención especial durante los procedimientos de tratamiento de conducto.


Asunto(s)
Humanos , Cavidad Pulpar/diagnóstico por imagen , Microtomografía por Rayos X , Diente Molar/diagnóstico por imagen , Cavidad Pulpar/anatomía & histología , Malasia , Diente Molar/anatomía & histología
7.
BMC Oral Health ; 24(1): 200, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38326901

RESUMEN

INTRODUCTION: Morphological and morphometric features of the teeth are of interest to various clinical and academic dental and medical fields including prosthodontics, orthodontics, anatomy and anthropology, pathology, archeology, and forensic dentistry. These have been more or less researched in the case of the permanent dentition. However when it comes to the primary dentition, the literature is scarce and controversial. No study worldwide exists on the cutoff points (thresholds) for sex identification; no study exists on metric or nonmetric traits of deciduous teeth in Iranians. Hence, the aim of the study was to assess both the metric and nonmetric traits of primary molars, as well as their cut-off points for sex identification. METHODS: In this epidemiological cross-sectional study, pretreatment casts of 110 children (51 boys and 59 girls) aged 6 to 12 years were collected. Maxillary and mandibular first and second primary molars were evaluated regarding their metric traits (mesiodistal and buccolingual widths) and 9 nonmetric traits (Accessory cusp on the upper D, Accessory cusp on the lower D, Fifth cusp on the upper E, Carabelli's cusp on the upper E, Protostylid on the lower E, Fifth cusp on the lower E, Sixth cusp on the lower E, Tuberculum intermedium [metaconulid] on the lower E, and Deflecting wrinkle on the lower E). ROC curves were used to identify cut-off points for sex determination as well as the usefulness of metric measurements for this purpose. Data were analyzed using independent-samples and paired-samples t-tests, McNemar, Fisher, and chi-square tests, plus Pearson and Spearman correlation coefficients (α = 0.05). RESULTS: All the primary molars' coronal dimensions (both mesiodistal and buccolingual) were extremely useful for sex identification (ROC curves, all P values ≤ 0.0000099). Especially, the mandibular primary molars (areas under ROC curves [AUCs] between 85.6 and 90.4%, P values ≤ 0.0000006) were more useful than the maxillary ones (AUCs between 80.4 and 83.1%, P values ≤ 0. 0000099). In the mandible, the first primary molar (maximum AUC = 90.4%) was better than the second molar (maximum AUC = 86.0%). The optimum thresholds for sex determination were reported. Sex dimorphism was significant in buccolingual and mesiodistal crown widths of all the primary molars (all P values ≤ 0.000132), but it was seen only in the case of 2 nonmetric traits: Deflecting wrinkle (P = 0.001) and Tuberculum intermedium (metaconulid, P = 0.029) on the lower Es, taking into account the unilateral and bilateral cases. The occurrence of nonmetric traits was symmetrical between the right and left sides (all P values ≥ 0.250). All mesiodistal and two buccolingual molar measurements were as well symmetrical (P > 0.1); however, two buccolingual measurements were asymmetrical: in the case of the maxillary E (P = 0.0002) and mandibular D (P = 0.019). There were three weak-to-moderate correlations between the nonmetric traits of the mandibular second molars (Spearman correlations between 22.7 and 37.5%, P values ≤ 0.045). Up to 6 concurrent nonmetric traits were observed in the sample, with 53.6% of the sample showing at least 2 concurrent nonmetric traits at the same time, without any sex dimorphism (P = 0.658). CONCLUSION: Sex dimorphism exists considerably in primary molars' sizes, but it is not as prevalent in their nonmetric traits or abnormalities. Primary molars' crown sizes are useful for sex identification; we calculated optimum cut-off points for this purpose, for the first time.


Asunto(s)
Pueblos de Medio Oriente , Diente Molar , Diente , Humanos , Masculino , Niño , Femenino , Estudios Transversales , Irán/epidemiología , Diente Molar/anatomía & histología , Diente/anatomía & histología , Odontometría
8.
J Hum Evol ; 188: 103481, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38382132

RESUMEN

Since the initial discovery of Paranthropus robustus at the site of Kromdraai in 1938, the hypodigm of this species has been expanded by subsequent work at the localities of Swartkrans and Drimolen, with a few fossils also known from Cooper's D, Gondolin and Sterkfontein Member 5. Beginning in 2014, systematic excavations at Kromdraai uncovered a large and previously unknown fossiliferous area, shedding light on Units O and P in the earliest part of the site's stratigraphic sequence. The aim of this paper is to provide detailed descriptions and illustrations of 30 P. robustus craniodental specimens recovered between 2014 and 2017 within the Unit P deposits at Kromdraai. This new sample predates all prior conspecific specimens found at this site (including the holotype of P. robustus from Kromdraai, TM 1517). Its basic dental morphology dimensions and cranial features are compared in a preliminary analysis with other P. robustus samples. The P. robustus sample from Kromdraai Unit P documents previously unknown portions of the P. robustus juvenile cranium. The new dental and cranial remains aid in the exploration of potential morphological distinctions between site-specific P. robustus samples and are compared favorably in size and morphology with the small P. robustus specimens from Drimolen (e.g., DNH 7). These findings do not support the hypothesis that the specimens from Drimolen belong to a different taxonomic group. Instead, they reinforce the presence of a significant degree of sexual dimorphism within P. robustus. The Kromdraai Unit P specimens also contribute to the biodemographic profile of P. robustus. The notable prevalence of infants (i.e., juvenile individuals before the emergence of their first permanent molars) mirrors the natural mortality profiles observed in wild chimpanzees. This suggests a closer resemblance in the processes of accumulation in Kromdraai Unit P and Drimolen than at Swartkrans.


Asunto(s)
Fósiles , Hominidae , Humanos , Animales , Hominidae/anatomía & histología , Sudáfrica , Diente Molar/anatomía & histología , Pan troglodytes
9.
Can Vet J ; 65(2): 156-161, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38304483

RESUMEN

Background: The study of the morphological parameters of teeth on dental radiographic images, especially evaluation of the pulp canal/root ratio (PCRR), has been presented as a reliable method to estimate age both in humans and animals. Evaluating PCRR involves a simple, nondestructive procedure that can be used both in living individuals and in cadavers. There is a scarcity of studies assessing the relationship between PCRR and age in dogs (Canis lupus familiaris). Objective: The aim of this study was to evaluate the relationship between PCRR and age in Yorkshire terrier dogs. Animals and procedures: Dental radiographs of 53 Yorkshire terrier dogs from the database of the Odontovet Veterinary Dentistry Center (Brazil) were analyzed. Using ImageJ software, 3 consecutive measurements of the widths of 2 roots (mesial and distal) and their respective pulp canals were taken at both mandibular molar teeth (left, 309 and right, 409). The PCRR was then calculated using width means. Results: The PCRR decreased with increasing age in both mesial (0.21 ± 0.09 in animals aged < 24 mo, 0.12 ± 0.04 in animals aged between 25 and 96 mo, and 0.09 ± 0.03 in dogs aged > 96 mo) and distal (0.24 ± 0.11, 1.01 ± 0.03, and 0.09 ± 0.03, by the same order) roots. A statistically significant, moderate negative correlation was demonstrated between age and PCRR of the mesial [rs (97) = -0.545; P < 0.001] and distal [rs (98) = -0.578; P < 0.001] roots. Conclusion and clinical relevance: This work contributes to the knowledge of PCRR in dogs and its relationship with age, paving the way for further studies using larger samples in different canine breeds.


Estimation de l'âge par le rapport canal pulpaire/racine chez des chiens de race Yorkshire. Contexte: L'examen des paramètres morphologiques des dents sur des radiographies dentaires, particulièrement l'évaluation du rapport canal pulpaire/racine (PCRR), a été présenté comme une méthode fiable d'estimer l'âge chez les humains et les animaux. L'évaluation du PCRR est faite au moyen d'une procédure simple et non-destructive qui peut être utilisée autant chez les individus vivants que sur des cadavres. Il y a peu d'études évaluant la relation entre le PCRR et l'âge chez les chiens (Canis lupus familiaris). Objectif: L'objectif de la présente étude était d'évaluer la relation entre le PCRR et l'âge chez des chiens de race Yorkshire. Animaux et procédures: Les radiographies dentaires de 53 chiens de race Yorkshire provenant de la base de données du Centre de dentisterie vétérinaire Odontovet (Brésil) ont été analysées. À l'aide du logiciel ImageJ, 3 mesures consécutives de la largeur de 2 racines (mésiale et distale) et de leur canal pulpaire respectif ont été prises au niveau des dents molaires mandibulaires (gauche, 309 et droite, 409). Le PCRR a par la suite été calculé utilisant les moyennes des largeurs. Résultats: Le PCRR diminuait avec une augmentation de l'âge autant pour la racine mésiale (0,21 ± 0,09 chez les animaux âgés de < 24 mo, 0,12 ± 0,04 chez les animaux âgés entre 25 et 96 mo, et 0,09 ± 0,03 chez les chiens de > 96 mo) que pour la racine distale (0,24 ± 0,11, 1,01 ± 0,03, 0,09 ± 0,03, dans le même ordre d'âge). Une différence statistiquement significative, corrélation modérément négative a été mise en évidence entre l'âge et le PCRR pour la racine mésiale [rs (97) = −0,545; P < 0,001] et la racine distale [rs (98) = −0,578; P < 0,001]. Conclusion et pertinence clinique: Cette étude contribue à la connaissance du PCRR chez les chiens et sa relation avec l'âge, ouvrant la voie à des études ultérieures avec un échantillonnage plus grand et différentes races de chien.(Traduit par Dr Serge Messier).


Asunto(s)
Cavidad Pulpar , Raíz del Diente , Humanos , Perros , Animales , Cavidad Pulpar/diagnóstico por imagen , Raíz del Diente/diagnóstico por imagen , Raíz del Diente/anatomía & histología , Mandíbula , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología
10.
Evolution ; 78(3): 463-479, 2024 Feb 29.
Artículo en Inglés | MEDLINE | ID: mdl-38147004

RESUMEN

Phylogenetically, the tribosphenic molars-prototypes of multi-cusped cheek teeth in marsupial and placental mammals-are derived from the single-cusped conical teeth of reptiles through the addition of cusps. Ontogenetically, mammalian molars are formed through the interface between the dental epithelium and mesenchyme (future enamel-dentin junction), becoming geometrically complex by adding epithelial signaling centers, called enamel knots, which determine future cusp positions. To reevaluate cusp homologies in Mesozoic mammals from an ontogenetic perspective, this study tracked molar development in a living placental mammal species, the house shrew (Suncus murinus), whose molars are morphologically the least derived from tribosphenic prototypes. The development of shrew molars proceeded as if it replayed the evolutionary process of tribosphenic molars. The first formed enamel knots gave rise to the evolutionarily oldest cusps-upper paracone and lower protoconid. The order of formation of other enamel knots and their location in development seemed to trace the order of cusp appearance in evolution. The parallel relationship between ontogeny and phylogeny of mammalian molars, if any, suggests that a change in the timing between developmental events rather than a change in the morphogenetic mechanism itself, should have been a major causal factor for the evolutionary transformation of tooth morphology.


Asunto(s)
Marsupiales , Diente , Animales , Femenino , Embarazo , Musarañas , Placenta , Diente Molar/anatomía & histología , Mamíferos/genética , Mamíferos/anatomía & histología , Diente/anatomía & histología , Filogenia , Marsupiales/anatomía & histología
11.
PLoS One ; 18(12): e0291308, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38100471

RESUMEN

Pleistocene Pongo teeth show substantial variation in size and morphology, fueling taxonomic debates about the paleodiversity of the genus. We investigated prominent features of the enamel-dentine-junction junction (EDJ)-phylogenetically informative internal structures-of 71 fossil Pongo lower molars from various sites by applying geometric morphometrics and conducted paleoproteomic analyses from enamel proteins to attempt to identify extinct orangutan species. Forty-three orangutan lower molars representing Pongo pygmaeus and Pongo abelii were included for comparison. The shape of the EDJ was analyzed by placing five landmarks on the tip of the main dentine horns, and 142 semilandmarks along the marginal ridges connecting the dentine horns. Paleoproteomic analyses were conducted on 15 teeth of Late Pleistocene Pongo using high-resolution tandem mass spectrometry. The geometric morphometric results show variations in EDJ shape regarding aspects of the height and position of the dentine horns and connecting ridges. Despite the issue of molar position and sample size, modern molars are distinguished from fossil counterparts by their elongated tooth outline and narrowly positioned dentine horns. Proteomic results show that neither a distinction of P. pygmaeus and P. abelii, nor a consistent allocation of fossil specimens to extant species is feasible. Based on the EDJ shape, the (late) Middle to Late Pleistocene Pongo samples from Vietnam share the same morphospace, supporting the previous allocation to P. devosi, although substantial overlap with Chinese fossils could also indicate close affinities with P. weidenreichi. The hypothesis that both species represent one chronospecies cannot be ruled out. Two fossil specimens, one from Tam Hay Marklot (Laos, Late Pleistocene), and another from Sangiran (Java, Early to Middle Pleistocene), along with some specimens within the Punung sample (Java), exhibit affinities with Pongo abelii. The Punung fossils might represent a mix of early Late Pleistocene and later specimens (terminal Pleistocene to Holocene) related to modern Pongo. The taxonomy and phylogeny of the complete Punung sample needs to be further investigated.


Asunto(s)
Hominidae , Pongo abelii , Diente , Animales , Pongo/anatomía & histología , Hominidae/anatomía & histología , Proteómica , Diente Molar/anatomía & histología , Pongo pygmaeus , Fósiles
12.
Acta Med Acad ; 52(2): 77-87, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37933504

RESUMEN

OBJECTIVE: This study aimed to analyze the crown and root morphology of maxillary and mandibular third molars, and assess their position in relation to adjacent anatomical structures using clinical examination and radiographic images. MATERIALS AND METHODS: A total of 176 extracted impacted or partially impacted third molars were included in this study. Orthopantomogram images (OPG) were used to evaluate the number of roots, position, depth of impaction relative to the occlusal plane of the second molar, and angulation of maxillary and mandibular third molars. The extracted teeth were examined to determine the actual number of roots. The root morphology was classified using the Alavi classification system for maxillary third molars and the Machado classification for mandibular third molars. Additionally, the number of cusps, crown dimensions, and morphology were analyzed using digital and dental calipers. RESULTS: The extracted samples exhibited a significantly higher number of roots compared to the number assessed on OPG images (P<0.001). The majority of mandibular third molars had two fused roots (37.39%) and a five-cuspid crown (48.70%), while maxillary third molars had three fused roots (26.23%) and four cusps (42.62%). Both maxillary (60.66%) and mandibular third molars (61.74%) were predominantly vertically positioned. Regarding the depth of impaction, maxillary third molars were primarily classified as Class C (65.57%), while mandibular third molars were classified as Class B (47.83%). Differences in crown shape were observed, with maxillary crowns being mostly triangular (36.07%) and mandibular crowns being oval (38.26%). Maxillary third molars had shorter crowns compared to mandibular third molars (P<0.05). CONCLUSION: The root morphology of maxillary and mandibular third molars in the population of Bosnia and Herzegovina displays variability. Orthopantomogram imaging was found to be inadequate for accurate determination of the number of roots in third molars. The number of cusps on third molars cannot be relied upon as a predictor of the number of roots. The study's findings will have implications for dental practice, particularly for oral surgeons and restorative dentists.


Asunto(s)
Tercer Molar , Raíz del Diente , Humanos , Tercer Molar/anatomía & histología , Raíz del Diente/anatomía & histología , Diente Molar/anatomía & histología , Coronas , Radiografía
13.
BMC Oral Health ; 23(1): 856, 2023 11 13.
Artículo en Inglés | MEDLINE | ID: mdl-37957637

RESUMEN

BACKGROUND: Knowledge about the anatomy and morphology of the root canal system is essential for successful surgical and non-surgical root canal treatments. However, precise assessment of the root morphology and anatomy is not often possible on two-dimensional radiographs. This study aimed to investigate the association of root morphology of mandibular second molars on panoramic-like and axial views of cone-beam computed tomography (CBCT). METHODS: This cross-sectional study evaluated 1,231 CBCT scans of mandibular second molars obtained between October 2018 and February 2022 that were retrieved from the archives of a private radiology clinic. Panoramic-like images were reconstructed from the CBCT scans. The root morphology of mandibular second molars was classified on panoramic-like images as type 1, 2, 3, 4, or 5. The root pattern on axial CBCT images was classified into three types of single, double and C-shaped. The association of root morphology on panoramic-like and axial CBCT views was analyzed by the Chi-square test and Fisher's exact test at 0.05 level of significance. RESULTS: Of all, 62.7% of mandibular second molars were type 1; out of which, 97.3% had a double-root pattern on axial CBCT images. Also, 28.6% of them were type 2; of which, 92.6% had a double-root pattern. Moreover, 3.9% were type 3; of which, 47.9% had a C-shaped pattern; 0.9% were type 4, and 45.5% of them showed a single-root pattern; 3.8% were type 5 with 76.6% of them showing a single-root pattern. The prevalence of C-shaped canals was higher in females, and most C-shaped canals had a C3 pattern. CONCLUSION: Root morphology on panoramic-like CBCT views had a strong association with the root canal pattern on axial CBCT views. According to the results, mandibular second molars with a type 3 morphology on panoramic-like CBCT images are highly probable to have a C-shaped canal.


Asunto(s)
Cavidad Pulpar , Raíz del Diente , Femenino , Humanos , Estudios Transversales , Raíz del Diente/diagnóstico por imagen , Raíz del Diente/anatomía & histología , Cavidad Pulpar/diagnóstico por imagen , Cavidad Pulpar/anatomía & histología , Mandíbula/diagnóstico por imagen , Mandíbula/anatomía & histología , Tomografía Computarizada de Haz Cónico/métodos , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología
14.
Aust Endod J ; 49(3): 684-689, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37792419

RESUMEN

To describe the endodontic treatment of a germinated composite odontome with atypical internal anatomy. A 35-year-old male presented with pain in the left mandibular second molar region. Intraoral examination and Cone-Beam Computed Tomography (CBCT) revealed a rare case of a germinated composite odontome with a 3-2-1 Vertucci configuration in the mesial root. Occlusal morphology and mesial root configuration required modifications in methods of isolation and access cavity preparation. Contemporary tools like magnification, ultrasonics and controlled memory rotary files were essential for executing the treatment plan. The tooth was functional at 18 months follow up and radiographs revealed no abnormality.


Asunto(s)
Cavidad Pulpar , Anomalías Dentarias , Masculino , Humanos , Adulto , Cavidad Pulpar/diagnóstico por imagen , Cavidad Pulpar/anatomía & histología , Mandíbula , Tomografía Computarizada de Haz Cónico/métodos , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología , Raíz del Diente/diagnóstico por imagen , Raíz del Diente/anatomía & histología
15.
Rom J Morphol Embryol ; 64(3): 437-442, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37867362

RESUMEN

Especially in molars that may have sometimes aberrant additional root canals, the complexity of tooth internal morphology in individual cases sometimes does not match to admitted classification rules and underlines the risk of missed anatomy during the endodontic management. To our knowledge, a permanent mandibular second molar with independent five roots, three mesial and two distal, each of them harboring a single canal, was not yet reported. Despite the treatment difficulties this tooth could be successfully approached by using dental operative microscope and cone-beam computed tomography (CBCT) with small field of view. Though CBCT is not a routine imagistic examination, in case of atypical tooth anatomy aiming to establish adequate diagnosis and treatment plan, the successful clinical outcome prevails over the irradiation dose.


Asunto(s)
Mandíbula , Raíz del Diente , Humanos , Raíz del Diente/diagnóstico por imagen , Mandíbula/diagnóstico por imagen , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología , Tomografía Computarizada de Haz Cónico/métodos , Cavidad Pulpar/diagnóstico por imagen
16.
BMC Oral Health ; 23(1): 738, 2023 10 10.
Artículo en Inglés | MEDLINE | ID: mdl-37817146

RESUMEN

BACKGROUND: Double teeth are usually the result of an abnormality in the developing tooth germ. Double teeth can occur in either the primary or permanent dentition, with the majority of cases concerning permanent teeth reported in the anterior teeth and less frequently in the molar teeth. CASE PRESENTATION: This report illustrates five cases of double teeth in molars with pulp and periapical disease, including one case of geminated teeth and four cases of fused teeth. Radiographic findings revealed the presence of extra teeth on the buccal aspect of the molar in five cases, with or without communication between the two root canal systems. Root canal treatment was performed by using CBCT and a dental operating microscope. The treatment outcome was good in all five cases. CONCLUSION: The diagnosis and treatment of double teeth requires special attention. The root canal system should be carefully explored to obtain a full understanding of the anatomy, allowing it to be fully cleaned and obturated. Proper anatomical structure analysis prior to treatment facilitates the development of an appropriate treatment plan, thereby increasing the likelihood of successful treatment both aesthetically and functionally.


Asunto(s)
Dientes Fusionados , Enfermedades Periapicales , Humanos , Cavidad Pulpar/anatomía & histología , Tratamiento Conservador , Diente Molar/anatomía & histología , Enfermedades Periapicales/diagnóstico por imagen , Enfermedades Periapicales/terapia , Tomografía Computarizada de Haz Cónico/métodos , Raíz del Diente
17.
Aust Endod J ; 49(3): 614-622, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37665125

RESUMEN

This CBCT-based study analysed morphometric relationships in Mesio-Buccal (MB) roots of maxillary first molars (MFM). 133 MFM with two MB canals were assessed and classified using Vertucci's classification. MB roots' length and MB1-MB2 canals inter-orifice distances (IOD) were noted. The data were analysed using SPSS software. The most frequently present canal was type IV (59.4%) followed by type II (40.6%). Mean MB roots' length for canals exhibiting type IV was 9.26 ± 0.21 mm and of those exhibiting type II was 12.8 ± 0.42 mm. Statistically significant relationship was found between MB root length and canal type. Mean IOD for type II and type IV canals was 2.4 ± 0.47 and 3.8 ± 0.21 mm, respectively. Statistically significant relationship was found between IOD and canal type. Length of MB root and IOD had a significant association with canal type present in MFM. This knowledge can enhance clinicians' understanding of canal morphology which can increase predictability and success rate of endodontic treatment.


Asunto(s)
Tomografía Computarizada de Haz Cónico Espiral , Arabia Saudita , Tomografía Computarizada de Haz Cónico , Maxilar/diagnóstico por imagen , Raíz del Diente/diagnóstico por imagen , Raíz del Diente/anatomía & histología , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología , Cavidad Pulpar/diagnóstico por imagen , Cavidad Pulpar/anatomía & histología
18.
Aust Endod J ; 49(3): 750-768, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37688283

RESUMEN

A novel system to classify root and canal morphology was recently introduced (Ahmed et al. 2017). This systematic review aimed to answer the following research question: Does the Ahmed et al. system provide a more accurate and practical classification of root and canal anatomy compared to other classifications? A literature search was conducted in Google Scholar, Scopus and Wiley Online Library to identify the citation counts for the article entitled 'A new system for classifying root and root canal morphology; doi.org/10.1111/iej.12685'. After removal of duplicates and unrelated articles, 15 studies were included and analysed. All studies compared the Ahmed et al. system with the Vertucci classification. Results revealed that both systems were able to classify simple canal configurations in single-rooted anterior and premolar teeth, disto-buccal and palatal roots of maxillary molars. However, the Ahmed et al. system provided more accurate and comprehensive categorisations of single-rooted teeth with complex canal anatomy, multi-rooted maxillary and mandibular premolars and the mesio-buccal root of maxillary molars. Further evidence on the utility of the Ahmed et al. system is required using other diagnostic devices especially in molars.


Asunto(s)
Tratamiento del Conducto Radicular , Raíz del Diente , Diente Molar/anatomía & histología , Raíz del Diente/anatomía & histología
19.
J Oral Sci ; 65(4): 226-231, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37532527

RESUMEN

PURPOSE: To investigate the root and canal morphology of mandibular second molars, including anatomical variations, in a Black South African population using two classification systems. METHODS: Cone-beam computed tomography images of 386 teeth were evaluated. The number of roots and canal configurations were categorized using the classifications of Vertucci (with modifications by Sert and Bayirli) and Ahmed et al. (including the modified Melton classification). Relationships between variables were assessed using Fisher's exact test (P < 0.05). RESULTS: Mandibular second molars were predominantly two-rooted (91.7%). The majority of teeth had three canals including Type IV mesial (41.2%) and Type I (75.1%) distal (Ahmed et al. configuration: 2MDM M2 D1). Three or more canals were present in almost one-fifth of mesial (n = 72/386, 18.6%) and a small number of distal (n = 21/386, 5.4%) roots. Males displayed additional canals more frequently in the distal root (P = 0.02). C-shaped anatomy was found in 5.7%. Among the C-shapes, the most common was Melton's Type III in the coronal (50%), middle (81%) and apical (72%) thirds. CONCLUSION: In this population, mandibular second molar teeth exhibited diverse morphology, which would have clinical significance for endodontic practitioners. The Ahmed et al. classification provided a better description than the Vertucci classification.


Asunto(s)
Cavidad Pulpar , Mandíbula , Masculino , Humanos , Sudáfrica , Cavidad Pulpar/diagnóstico por imagen , Cavidad Pulpar/anatomía & histología , Mandíbula/diagnóstico por imagen , Estudios Retrospectivos , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología , Raíz del Diente/diagnóstico por imagen , Raíz del Diente/anatomía & histología , Tomografía Computarizada de Haz Cónico/métodos
20.
Int. j. morphol ; 41(4): 1112-1117, ago. 2023. tab
Artículo en Español | LILACS | ID: biblio-1514332

RESUMEN

El objetivo de este estudio fue utilizar la Tomografía Computarizada de Haz Cónico (TCHC) para investigar la configuración anatómica, prevalencia y distribución del conducto mesiovestibular Dos (MV2) en molares superiores de una subpoblación chilena, considerando variables como la presencia del conducto MV2, la clasificación de Vertucci, el género y edad. Estudio observacional de corte transversal. La muestra consistió en Tomografías Computarizadas de Haz Cónico tomadas en la clínica odontológica de la Universidad Andrés Bello (Viña del Mar). Se calculó el tamaño muestral utilizando la fórmula de población conocida, lo que resultó en 262 tomografías. Los examinadores se calibraron utilizando el coeficiente Kappa de Cohen, para luego analizar las variables mediante un estudio imagenológico utilizando el software I-CAT Visión. Se analizaron 439 primeros y segundos molares superiores. La prevalencia del conducto MV2 en primeros molares fue del 63,74 %, mientras que, en segundos molares, fue del 20,04 %. La prevalencia en primeros molares fue mayor en hombres (73,86 %) que en mujeres (58,62 %), mientras que, en segundos molares, fue del 15,81 % en mujeres y del 28,41 % en hombres. En relación con la edad, en los primeros molares la diferencia fue significativa en el rango de 18 a 40 años (66,49 %). En cuanto al tipo de configuración según Vertucci (2005), el 70 % de los primeros molares presentó una configuración Tipo II, y un 23,65 % Tipo IV, con resultados similares en los segundos molares. El presente estudio demostró que los conductos MV2 son frecuentes en la población analizada, especialmente en los primeros molares, y que la configuración Tipo II es la más prevalente. Además, se observó una mayor prevalencia en hombres y en el rango de 18 a 40 años. Estos hallazgos proporcionan información relevante sobre la anatomía radicular en la población y pueden contribuir a mejorar los resultados de tratamiento.


SUMMARY: The aim of this study was to use Cone-beam Computed Tomography (TCHC) to investigate the anatomical configuration, prevalence, and distribution of the Second Mesiobuccal (MB2) canal in upper molars of a Chilean subpopulation, considering variables such as the presence of MB2 canal, Vertucci classification, gender, and age. Cross-sectional observational study. The sample consisted of TCHC scans taken at the dental clinic of Universidad Andrés Bello (Viña del Mar). The sample size was calculated using the formula for known population, resulting in 262 scans. The examiners were calibrated using Cohen's Kappa coefficient, then the variables were analyzed through an imaging study using I-CAT Vision software. 439 first and second upper molars were analyzed. The prevalence of MB2 canal in first molars was 63.74 %, while in second molars, it was 20.04 %. The prevalence in first molars was higher in males (73.86 %) than in females (58.62 %), while in second molars, it was 15.81 % in females and 28.41 % in males. Regarding age, in first molars the difference was significant between the age range of 18 to 40 years (66.49 %). Regarding the type of configuration according to Vertucci, 70 % of the first molars had Type II configuration, and 23.65 % had Type IV, with similar results in second molars. The present study demonstrated that MB2 canals are frequent in the analyzed population, especially in first molars, and Type II configuration is the most prevalent. Additionally, a higher prevalence was observed in males and in the age range of 18 to 40 years. These findings provide relevant information about root anatomy in the studied population and can contribute to improving treatment outcomes.


Asunto(s)
Humanos , Masculino , Femenino , Adolescente , Adulto , Persona de Mediana Edad , Anciano , Adulto Joven , Cavidad Pulpar/diagnóstico por imagen , Tomografía Computarizada de Haz Cónico , Diente Molar/diagnóstico por imagen , Chile , Estudios Transversales , Cavidad Pulpar/anatomía & histología , Diente Molar/anatomía & histología
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