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1.
Orv Hetil ; 161(28): 1166-1174, 2020 07.
Artículo en Húngaro | MEDLINE | ID: mdl-32609624

RESUMEN

INTRODUCTION AND AIM: The aim of our study was to investigate the influence of the occlusal support, and mandibular third molars on mandibular angle and condylar fractures. METHOD AND RESULTS: Patients with unilateral and isolated angle or condylar fractures were included in this retrospective, cross-sectional study. Data was collected from patient records and panoramic x-rays. The predictor variables included the type of occlusal support and the presence or absence of third molars. The outcome variable was angle or condylar fracture, while other predictor variables included demographic factors. Bivariate (χ2 test) and logistic regression analyses were conducted to investigate the associations between variables and the outcome. 43 angle (mean age: 29.9 ± 12.8 years; 98.4% male) and 37 condylar (mean age: 46.8 ± 20.2 years; 62.2% male) fracture cases were included in this study. Bilateral occlusal support was present in 81.4% of angle fracture group and in 51.3% of condylar fracture group (p<0.001). In the case of bilateral occlusal support, an odds ratio (OR) of 4.2 was found for angle fractures (p<0.006). A third molar was present in 86% of the angle fracture group and in 43.2% of the condylar fracture group (p<0.001). The presence of a third molar exhibited an odds ratio of 8.1 for the angle fractures (p<0.001). When bilateral occlusal support and third molar were present simultaneously, the risk was 15.9 times higher for an angle fracture (p<0.001). CONCLUSION: The presence of occlusal support and/or third molars was significantly associated with angle fractures, however, the absence of occlusal support and/or third molars significantly correlated with condylar fractures. Orv Hetil. 2020; 161(28): 1166-1174.


Asunto(s)
Oclusión Dental , Mandíbula , Cóndilo Mandibular/lesiones , Fracturas Mandibulares/etiología , Tercer Molar/anatomía & histología , Diente Impactado/complicaciones , Adolescente , Adulto , Anciano , Estudios Transversales , Femenino , Humanos , Incidencia , Masculino , Fracturas Mandibulares/epidemiología , Persona de Mediana Edad , Tercer Molar/diagnóstico por imagen , Radiografía Panorámica , Estudios Retrospectivos , Factores de Riesgo , Corona del Diente/diagnóstico por imagen , Adulto Joven
2.
Int. j. morphol ; 37(4): 1382-1386, Dec. 2019. tab
Artículo en Inglés | LILACS | ID: biblio-1040141

RESUMEN

Agenesis of permanent teeth is the most frequent dental anomaly. The most affected tooth is the third molar (M3), and its congenital absence poses interesting questions from a clinical and evolutionary perspective. M3 agenesis can occur isolated or as part of syndromes. Researchers have reported prevalences that vary largely among populations, between 5 % and 56 %, with a mean prevalence of 22.6 %. Previous Chilean studies, mainly in Northern populations, have determined a prevalence between 19.8 % and 26.7 %. The aim of this work was to assess the prevalence of M3 agenesis and to characterize its presentation in a sample from Santiago, the largest to date in a M3 agenesis prevalence study in Chile. In this study, 535 panoramic radiographies and clinical histories of patients from the Dental Clinic of the Universidad de Chile were used to determine prevalence and distribution according to sex, affected tooth, and location (left or right; maxilla or mandible). The Chi-square test was used to assess statistical significance in distribution. The calculated M3 agenesis prevalence was of 12.89 %. No statistically significant differences were found between sexes, sides or location within the jaws. The agenesis of one third molar was more common, then two, three and finally of all the third molars. The prevalence of M3 agenesis in the sample is 12.89 %, with a random manner of presentation. We propose that as it currently stands, M3 agenesis should be considered an anatomical variation rather than a developmental anomaly.


La agenesia de dientes definitivos es la anomalía dental más común. El diente más afectado es el tercer molar (M3), y su ausencia congénita plantea preguntas interesantes desde una perspectiva clínica y evolutiva. La agenesia de M3 puede ocurrir de manera aislada o asociada a síndromes. Estudios a nivel mundial reportan una prevalencia variable entre poblaciones: 5 % a 56 %, con una prevalencia media del 22,6 %. Estudios chilenos anteriores, principalmente en poblaciones del norte, han determinado una prevalencia entre 19,8 % y 26,7 %. El objetivo de este trabajo fue determinar la prevalencia de agenesia de M3 y caracterizar su presentación en una muestra de Santiago, la más grande hasta la fecha en un estudio de prevalencia de agenesia de M3 en Chile. Se utilizaron 535 radiografías panorámicas y antecedentes de pacientes atendidos en la Clínica Odontológica de la Universidad de Chile para evaluar la prevalencia y modo de presentación de la agenesia de M3. Se analizó su distribución según ubicación, sexo y simetría, mediante test estadístico Chi-cuadrado. Se calculó una prevalencia de agenesia de M3 de 12,89 %, sin un patrón claro ni estadísticamente significativo en su distribución. Fue más común la agenesia de un tercer molar, luego de dos, tres y finalmente de todos los terceros molares. La prevalencia de agenesia en una muestra de la Región Metropolitana es de 12,89 % y su distribución es aleatoria según la ubicación, sexo y simetría. Se propone que esta condición actualmente debiera considerarse como una variación anatómica más que a una anomalía del desarrollo.


Asunto(s)
Humanos , Masculino , Femenino , Anodoncia/epidemiología , Tercer Molar/anomalías , Radiografía Panorámica , Distribución de Chi-Cuadrado , Chile/epidemiología , Prevalencia , Distribución por Sexo , Variación Anatómica , Anodoncia/diagnóstico por imagen , Tercer Molar/anatomía & histología , Tercer Molar/diagnóstico por imagen
3.
Am J Orthod Dentofacial Orthop ; 156(2): 178-185, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31375227

RESUMEN

INTRODUCTION: This study aimed to identify significant factors affecting the spontaneous angular changes of impacted mandibular third molars as a result of second molar protraction. Temporary skeletal anchorage devices in the missing mandibular first molar (ML-6) or missing deciduous mandibular second molar (ML-E) with missing succedaneous premolar spaces provided traction. METHODS: Forty-one mandibular third molars of 34 patients (10 male and 24 female; mean age 18.3 ± 3.7 years) that erupted after second molar protraction were included in this study. They were classified into upright (U) and tilted (T) groups. Linear and angular measurements were performed at the time of treatment initiation (T1) and of ML-6 or ML-E space closure (T2). Regression analyses were used to identify significant factors related to third molar uprighting. RESULTS: Nolla stage (odds ratio [OR] 4.1), sex (OR 0.003 for male), third molar angulation at T1 (OR 1.1), missing tooth space (OR 0.006), rate of third molar eruption (OR 23.3), and rate of second molar protraction (OR 0.2) significantly affected third molar uprighting. Age, third molar angulation at T1, rate of third molar eruption, and rate of second molar protraction were significant factors for predicting third molar angulation at T2. CONCLUSIONS: Available space for third molar eruption before and after second molar protraction is not associated with uprighting of erupting third molars. Older patients whose third molars are in greater Nolla stage, are in a more upright position at T1, and have a greater eruption rate have a greater chance for third molar uprighting. Alternatively, an increase in second molar protraction rate results in mesial tipping of the third molars.


Asunto(s)
Maloclusión/prevención & control , Maloclusión/fisiopatología , Mandíbula/fisiopatología , Tercer Molar/fisiopatología , Diente Impactado/fisiopatología , Adolescente , Adulto , Puntos Anatómicos de Referencia , Diente Premolar , Femenino , Humanos , Masculino , Maloclusión/diagnóstico por imagen , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Diente Molar/anatomía & histología , Diente Molar/diagnóstico por imagen , Diente Molar/fisiopatología , Tercer Molar/anatomía & histología , Tercer Molar/diagnóstico por imagen , Aparatos Ortodóncicos , Cierre del Espacio Ortodóncico , Ortodoncia Correctiva , Erupción Dental , Diente Primario , Diente Impactado/complicaciones , Diente Impactado/diagnóstico por imagen , Adulto Joven
4.
Br J Oral Maxillofac Surg ; 57(8): 765-770, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31350031

RESUMEN

The study was designed to assess, by direct anatomical observations and cone-beam computed tomography (CT), the prevalence of a retromolar canal and foramen in relation to the mandibular third molar in dry human mandibles. Dry mandibles from European skeletons (n=89) were observed directly and after cone-beam CT scanning (Newtom VGI evo). The following variables were assessed: the presence of a retromolar foramen and canal; the presence of a third molar, and orientation of the third molar. From the total of 89 mandibles selected, 73 showed a retromolar foramen (49 of which were bilateral). A retromolar canal was identified in 64 mandibles based on cone-beam CT assessment, with a total of 101 canals, including 74 that were bilateral. A total of 112 hemimandibles contained a third molar. Orientation of the third molar did not seem to indicate the presence of retromolar foramina or canals. A similar prevalence of retromolar canals was found for both vertically (41/79) and mesially (17/33) orientated third molars. A retromolar foramen and canal were present in most mandibles, with more than half being bilateral. We were unable to confirm a potential relation between the retromolar foramen and canal on the one hand, and the orientation of the third molar on the other.


Asunto(s)
Tomografía Computarizada de Haz Cónico/métodos , Mandíbula , Tercer Molar , Cefalometría , Humanos , Mandíbula/anatomía & histología , Diente Molar , Tercer Molar/anatomía & histología , Alveolo Dental/anatomía & histología
5.
Methods Mol Biol ; 1922: 341-356, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30838589

RESUMEN

Third molar development and eruption are two related areas of major interest in dental research into the etiology of "wisdom tooth" impaction. Third molars are not only an excellent model for studying dental development but also of fundamental clinical importance because they are very frequently impacted. Because the third molar is located in the distal-most region of the oral cavity, clinical access is relatively challenging. With the increasingly widespread use of cone-beam computed tomography (CBCT) in dentistry, studies and measurements of the third molar and its eruption area have become considerably easier to do. Here we present a novel CBCT-based measurement methodology we developed for our recent investigations that we hope will also be useful for the broader dental research community.


Asunto(s)
Tomografía Computarizada de Haz Cónico/métodos , Imagenología Tridimensional/métodos , Tercer Molar/anatomía & histología , Corona del Diente/anatomía & histología , Humanos , Mandíbula/anatomía & histología , Mandíbula/crecimiento & desarrollo , Mandíbula/ultraestructura , Maxilar/anatomía & histología , Maxilar/crecimiento & desarrollo , Maxilar/ultraestructura , Tercer Molar/crecimiento & desarrollo , Tercer Molar/ultraestructura , Corona del Diente/crecimiento & desarrollo , Corona del Diente/ultraestructura
6.
J Int Med Res ; 47(1): 311-324, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30293503

RESUMEN

OBJECTIVE: To analyse the accuracy of a meta-analysis-based dental age assessment (DAA) method in Finnish paediatric patients and to compare the dental development between two generations of Finnish children. METHODS: Panoramic radiographs of Finnish Caucasian healthy children from two generations (early: born 1981-1984; subsequent: born 1996-2008) were analysed. All developing teeth on the left maxilla and mandible as well as the third permanent molars were analysed following Demirjian's classification. For each patient, dental age was calculated and compared with chronological age. Dental maturation patterns between the two groups were compared. RESULTS: The study included 200 Finnish Caucasian healthy children from two generations (early: aged 7-13 years; subsequent: aged 6-15 years). In the early generation, DAA underestimated the chronological age by a mean of 3.15 years. The underestimation was only 0.11 years in patients < 10 years, but 3.86 years in patients ≥ 10 years. In the subsequent generation, the dental age was overestimated by a mean of 0.34 years; by 0.40 years in patients < 10 years and by 0.08 years in patients ≥ 10 years. CONCLUSIONS: The present DAA method is applicable to current Finnish children. Differences in dental development between two generations of Finnish children were detected.


Asunto(s)
Mandíbula/diagnóstico por imagen , Maxilar/diagnóstico por imagen , Tercer Molar/diagnóstico por imagen , Radiografía Panorámica , Adolescente , Factores de Edad , Niño , Grupo de Ascendencia Continental Europea , Femenino , Finlandia , Humanos , Masculino , Mandíbula/anatomía & histología , Mandíbula/crecimiento & desarrollo , Maxilar/anatomía & histología , Maxilar/crecimiento & desarrollo , Tercer Molar/anatomía & histología , Tercer Molar/crecimiento & desarrollo , Estudios Retrospectivos , Factores de Tiempo
7.
Am J Orthod Dentofacial Orthop ; 154(4): 477-486, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30268258

RESUMEN

INTRODUCTION: In this study, we aimed to determine the effect of maxillary and mandibular posterior space discrepancies and third molar angulations on the overbite. METHODS: Pretreatment lateral cephalograms of 131 subjects were analyzed. The sample included 83 open-bite and 48 deepbite subjects. A multiple regression analysis was used to evaluate the influence of maxillary and mandibular posterior space discrepancies and third molar angulations (predictor variables) on overbite. Correlations between posterior space discrepancy and third molar angulation, and correlations between predictor variables and dental angulation and height of posterior teeth and incisors were evaluated with the Pearson correlation coefficient. Subgroups with accentuated negative overbite and deepbite (27 open-bite, 37 deepbite) were compared with t tests. RESULTS: The multiple linear regression analysis showed a positive association of the mesial angulation of the mandibular third molar with overbite. Posterior space discrepancy was negatively associated with posterior teeth mesial angulation and dentoalveolar height. However, these associations were weak, with no clinically significant implications. The deepbite subgroup showed significantly greater mesial angulation of the mandibular third molars than did the open-bite subgroup. CONCLUSIONS: There was no clinically significant effect of posterior space discrepancies and third molar angulations on overbite and dental angulation and height of posterior teeth and incisors.


Asunto(s)
Incisivo/anatomía & histología , Maloclusión de Angle Clase II/patología , Tercer Molar/anatomía & histología , Sobremordida , Diente Impactado/complicaciones , Adolescente , Puntos Anatómicos de Referencia , Brasil , Niño , Arco Dental/patología , Femenino , Humanos , Incisivo/patología , Modelos Lineales , Masculino , Mandíbula , Maxilar , Tercer Molar/diagnóstico por imagen , Mordida Abierta , Erupción Dental , Diente Impactado/patología
8.
Rev. cuba. estomatol ; 55(3): 1-11, jul.-set. 2018. ilus, tab
Artículo en Portugués | LILACS | ID: biblio-991069

RESUMEN

Introdução: os estágios de mineralização dentária têm sido utilizados em diversos estudos para a estimativa de idade, apresentando confiabilidade nos resultados. Objetivo: correlacionar a mineralização dos terceiros molares e a idade cronológica pelos métodos de Nolla, Demirjian e Nicodemo, Moraes e Médici Filho numa amostra populacional do nordeste brasileiro. Métodos: de um universo de 1 205 radiografias panorâmicas digitais, foram selecionadas 297 imagens de pacientes atendidos rotineiramente em um serviço de Radiologia Odontológica privado. Todas as imagens foram avaliadas em ambiente escurecido por três examinadores calibrados, utilizando as classificações de Nolla (1960), Demirjian (1973) e Nicodemo, Moraes e Médici Filho (1974). Os dados numéricos foram resumidos através das estatísticas descritivas de locação e dispersão. Para análise estatística foi ajustado um modelo de regressão linear simples considerando a idade como variável resposta. Para os testes, foi adotado o nível de significância de 5 porcento ciento. Resultados: o desenvolvimento dos terceiros molares foi mais adiantado no sexo masculino na maioria dos estágios, para os três métodos. Nos dentes superiores, o dimorfismo sexual foi mais evidente no estágio 7 de Nolla (diferença de 16,34 m no dente 18 e 14,43 m no dente 28). Nos dentes inferiores, as maiores diferenças ocorreram: no estágio 6 de Nolla (diferença de 13,92 m no 38 e 10,46 m no 48) e estágio 5 de Nicodemo (diferença de 16,23 m mais elevado no elemento 38 e 9,9 m no 48). O desenvolvimento dos dentes terceiros molares dos lados direito e esquerdo apresentou-se semelhante, contudo os dentes superiores apresentaram-se mais adiantados que os inferiores. O presente estudo permitiu o desenvolvimento de fórmulas baseadas em regressões lineares simples utilizando os três métodos propostos, possibilitando, assim, estimar a idade cronológica dos indivíduos da amostra. Conclusão: houve correlação do desenvolvimento dentário dos terceiros molares com a idade cronológica pelos três métodos(AU)


Introducción: las etapas de mineralización de los dientes se han utilizado en varios estudios para estimar la edad, lo cual ha mostrado resultados fiables. Objetivo: correlacionar la mineralización de los terceros molares y la edad cronológica por los métodos de Nolla, Demirjian y Nicodemo, Moraes y Medici Filho en una muestra de población del nordeste de Brasil. Métodos: a partir de un universo de 1 205 radiografías panorámicas digitales, se seleccionaron 297 imágenes de pacientes tratados de forma rutinaria en un servicio de radiología dental privada. Todas las imágenes fueron evaluadas en cuarto oscuro por tres examinadores calibrados, utilizando los métodos de Nolla (1960), Demirjian (1973) y Nicodemo, Moraes y Medici Filho (1974). Los datos numéricos se resumieron utilizando estadística descriptiva del contrato de arrendamiento y la dispersión. El análisis estadístico se ajustó un simple modelo de regresión lineal, considerando la edad como variable de respuesta. Para las pruebas, se adoptó el nivel de significación del 5 pr ciento. Resultados: el desarrollo de los terceros molares fue más temprano en los varones en la mayoría de las etapas, por los tres métodos. En los dientes superiores, el dimorfismo sexual fue más evidente en la etapa 7 de Nolla (diferencia de 16,34 m en el diente 18 y 14,43 m en el diente 28). En los dientes inferiores, las mayores diferencias ocurrieron: en la etapa 6 de Nolla (diferencia de 13,92 m no 38 y 10,46 m no 48) y etapa 5 de Nicodemo (diferencia de 16,23 m más elevado en el elemento 38 y 9,9 m no 48). El desarrollo de los dientes terceros molares de los lados derecho e izquierdo se presentó semejante, sin embargo los dientes superiores se presentaron más adelantados que los inferiores. Este estudio permitieron el desarrollo de formulaciones a base de regresiones lineales usando los tres métodos propuestos, permitiendo estimar la edad cronológica de los individuos en la muestra. Conclusiones: se observa una correlación de desarrollo de los dientes terceros molares con la edad cronológica por tres métodos(AU)


Introduction: dental mineralization stages have been used in several studies to estimate age, and the results obtained have been found to be reliable. Objective: correlate third molar mineralization and chronological age using the methods developed by Nolla, Demirjian, and Nicodemo, Moraes and Medici Filho in a population sample from Northeast Brazil. Methods: of a total 1 205 digital panoramic radiographs, 297 were selected of patients routinely seen in a private dental radiology service. All the images underwent darkroom evaluation by three qualified examiners using the methods developed by Nolla (1960), Demirjian (1973), and Nicodemo, Moraes and Medici Filho (1974). Numerical data were summarized by location and dispersion descriptive statistics. For statistical analysis a simple linear regression model was adjusted which considered age as response variable. A significance level of 5 percent was adopted for the tests. Results: third molar development occurred earlier in males in most stages by the three methods. In upper teeth, sexual dimorphism was more evident in Nolla stage 7 (difference of 16.34 m in tooth 18 and 14.43 m in tooth 28). In lower teeth, the greatest differences occurred in Nolla stage 6 (difference of 13.92 m in 38 and 10.46 m in 48) and Nicodemo stage 5 (difference of 16.23 m higher in tooth 38 and 9.9 m in 48). Third molar development was similar on the right and left sides, but greater in upper teeth than in lower teeth. The study allowed development of linear regression formulas based on the three methods proposed, making it possible to estimate the chronological age of the individuals in the sample. Conclusions: the three methods found a correlation between third molar development and chronological age(AU)


Asunto(s)
Humanos , Determinación de la Edad por los Dientes/métodos , Radiografía Panorámica/efectos adversos , Tercer Molar/anatomía & histología , Interpretación Estadística de Datos
9.
Arch Oral Biol ; 95: 134-140, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30107301

RESUMEN

OBJECTIVES: To investigate the anatomical variations of the root and root canal configuration of the human third molars. DESIGNS: A total of 130 maxillary and 130 mandibular third molars were collected from a native Chinese population. All teeth were scanned by micro-computed tomography. After 3D reconstruction, the root and canal morphology of each tooth was examined both qualitatively and quantitatively. RESULTS: For maxillary molars, a single fused root (67 cases, 51.5%) and a single root canal system (64 cases, 49.2%) was most common root/canal form; the typical three-rooted molars were detected only in 33 cases (25.4%), and the secondary MB canals were detected only in 9 molars (6.9%). For mandibular molars, 62 teeth were single-rooted (47.7%) and 42 had a single root canal system (32.3%); 20 singled-rooted and 60 double-rooted molars exhibited independent mesial and distal root canal systems (61.5%), and the type 1-1 canal was the most common configuration for mesial (57 cases) and distal (81 cases) root canal systems. C-shaped canals were detected in 11 maxillary and 36 mandibular single-rooted molars. The mean root surface area, root and crown volume of mandibular third molars were significantly higher than the maxillary third molars (P < 0.01). CONCLUSION: The root canal system of the third molars may exhibit several anatomic variations. Whereas in most of cases, the degree of the canal differentiation was at a low level, and the canal form was not complicate.


Asunto(s)
Tercer Molar/anatomía & histología , Odontometría/métodos , Raíz del Diente/anatomía & histología , Microtomografía por Rayos X , Adulto , Variación Anatómica , China , Femenino , Humanos , Masculino , Tercer Molar/diagnóstico por imagen , Raíz del Diente/diagnóstico por imagen
10.
J Endod ; 44(10): 1567-1574, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30154002

RESUMEN

Autotransplantation exhibits a number of advantages compared with other treatment options (ie, dental implants or fixed partial prostheses), such as greater resistance to occlusal loading, maintenance of the periodontal ligament and surrounding bone, and the potential for better esthetics. The aim of this study was to determine clinical outcomes for autotransplanted teeth with complete root formation using 3-dimensional-printed guiding templates and tooth replicas. Twenty-seven third molars with completely formed roots were autotransplanted. Each donor tooth and recipient site were examined clinically and radiographically (periapical radiographs). A selective cone-beam computed tomographic scan was taken of each donor tooth and recipient site. The images of the selected donor teeth were segmented and saved as stereolithography files. Similar to virtual planning of dental implants, correct angulation, rotation, and accurate positioning of the donor teeth were predefined using the stereolithography files. According to the virtually defined positions and dimensions of the donor teeth, 3-dimensional guiding templates and donor tooth replicas were printed. All autotransplantations were performed according to 1 treatment protocol and surgical technique. In 22 of the 24 transplanted teeth, no inflammation occurred during the healing period. At 2 years, no pathologic radiolucency or tooth resorption was observed in the 22 donor teeth. The autotransplanted teeth fulfilled the success criteria in 22 cases for a 91.7% success rate. Digital planning could potentially provide an accurate alternative to current autotransplantation techniques.


Asunto(s)
Implantación Dental/métodos , Implantes Dentales , Tercer Molar/trasplante , Impresión Tridimensional , Adulto , Tomografía Computarizada de Haz Cónico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tercer Molar/anatomía & histología , Tercer Molar/diagnóstico por imagen , Estudios Retrospectivos , Diseño de Software , Cirugía Asistida por Computador/métodos , Raíz del Diente , Trasplante Autólogo/métodos , Resultado del Tratamiento , Adulto Joven
11.
Br J Oral Maxillofac Surg ; 56(4): 267-271, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29525294

RESUMEN

The aims of this study were to find the incidence of bifurcation of the inferior dental nerve (IDN) canal, to describe the characteristics of this variant, and to examine the sensitivity and specificity of dental panoramic tomography to identify it. We classified bifurcations by size and position relative to the main canal and the lower third molar using cone-beam computed tomography (CT) and dental panoramic tomography. In our study of 281 patients, 106 (38%) had bifurcations, and in one quarter, these were classified as large accessory canals. Bifurcations were most commonly found posterior to the lower third molar (n=64, 57%) or within 2mm of the roots of the third molar (n=40, 38%). The sensitivity and specificity of dental panoramic tomography to identify all bifurcations was 11% (95% CI: 5.67 to 17.97) and 91% (95% CI: 85.58 to 94.68), respectively; this was 33% (95% CI: 15.63 to 55.32) and 94% (95% CI: 90.34 to 96.50), respectively, for large bifurcations. Our use of cone-beam CT suggested an incidence of bifid canals of 38%, with a variation in size and distribution in relation to the lower third molar. It also showed that the sensitivity of panoramic radiography to identify them was poor.


Asunto(s)
Nervio Mandibular/anomalías , Adolescente , Adulto , Anciano , Tomografía Computarizada de Haz Cónico , Femenino , Humanos , Masculino , Mandíbula/anomalías , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Mandíbula/inervación , Nervio Mandibular/anatomía & histología , Nervio Mandibular/diagnóstico por imagen , Persona de Mediana Edad , Tercer Molar/anatomía & histología , Tercer Molar/diagnóstico por imagen , Radiografía Panorámica , Adulto Joven
12.
Surg Radiol Anat ; 40(6): 647-652, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29594335

RESUMEN

PURPOSE: The retromolar canal (RMC) and foramen (RMF) are anatomic variants in the retromolar area of the mandible. The purpose of this study was to clarify the relationship between the RMC and RMF and related complications, and to reveal how the RMC could impact the mandibular anatomy using cone-beam computed tomography (CBCT) and panoramic images (PAN). MATERIALS AND METHODS: CBCT and PAN images of 50 patients were retrospectively analyzed to investigate the morphology of the RMC and RMF, and their impact on impacted third molar surgery and orthognathic surgery. RESULTS: In PAN images, neither the RMC nor RMF was detected. In CBCT images, the RMCs were detected in 26% (13/50) of the patients. A double RMC was detected on one side of one patient. The diameter of the RMC ranged from 0.8 to 2.9 mm (mean; 1.5 ± 0.6 mm), and the RMF ranged from 0.6 to 2.3 mm (mean; 1.1 ± 0.5 mm). No patients experienced unexpected bleeding. Unilateral postoperative hypoesthesia of the buccal gingiva in the molar region was reported in 6.7% of patients with the RMC. CONCLUSIONS: Hypoesthesia of the buccal gingiva in the lower molar region may be the main complication when the RMC is damaged.


Asunto(s)
Variación Anatómica , Mandíbula/anatomía & histología , Tercer Molar/cirugía , Procedimientos Quirúrgicos Orales/efectos adversos , Complicaciones Posoperatorias/epidemiología , Adolescente , Adulto , Anciano , Tomografía Computarizada de Haz Cónico , Femenino , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Nervio Mandibular/anatomía & histología , Persona de Mediana Edad , Tercer Molar/anatomía & histología , Tercer Molar/diagnóstico por imagen , Procedimientos Quirúrgicos Orales/métodos , Complicaciones Posoperatorias/etiología , Radiografía Panorámica , Estudios Retrospectivos , Adulto Joven
13.
Oral Maxillofac Surg ; 22(2): 231-233, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29455344

RESUMEN

The removal of displaced dental elements from deep anatomical spaces is a condition that requires the knowledge of the region and skills to perform the procedure. The lateral pharyngeal space contains important structures such as the internal carotid artery and close proximity with the cranium basis. The aim of this paper is to report a clinical case of a lower third molar displaced to the lateral pharyngeal space after a mandibular angle fracture and its treatment by surgical intervention. The tooth was removed under general anesthesia by direct approach and the fracture was reduced and fixed with a plate and screws. This case report illustrates the importance of an immediate procedure to avoiding severe complications and further damage to important anatomical structures.


Asunto(s)
Fracturas Mandibulares/cirugía , Tercer Molar/anatomía & histología , Tercer Molar/cirugía , Faringe/anatomía & histología , Extracción Dental/métodos , Diente Impactado/cirugía , Adulto , Placas Óseas , Tornillos Óseos , Brasil , Femenino , Fijación de Fractura/métodos , Humanos , Complicaciones Intraoperatorias , Fracturas Mandibulares/diagnóstico por imagen , Tercer Molar/diagnóstico por imagen , Base del Cráneo , Tomografía Computarizada por Rayos X , Diente Impactado/complicaciones , Adulto Joven
14.
Int Orthod ; 16(1): 82-90, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29459154

RESUMEN

OBJECTIVES: The aim of this study was to determine the effect of first premolar extraction with different anchorages as well as non-extraction on mandibular third molar angulation. MATERIALS AND METHODS: The pretreatment (T1) and posttreatment (T2) panoramic radiographs of one hundred patients from Hamadan (Iran), who underwent fixed orthodontic treatment were investigated and the angle between long axis of right mandibular third molars and a constructed horizontal plan (HRP) was measured. The sample was equally divided into four groups including first premolar extraction with maximum anchorage, that with moderate anchorage, that with minimum anchorage and non-extraction group. RESULTS: In the first premolar extraction groups with moderate and minimum anchorages, third molar angulation increased (8.12 and 7.48°, respectively) significantly from T1 to T2 (P=0.001 and 0.003, respectively), but in the first premolar extraction group with maximum anchorage and non-extraction group, increase in third molar angulation (2.84 and 0.8°, respectively) was not statistically significant (P=0.082 and 0.943, respectively). Third molar uprighting was significantly different among four groups using one-way ANOVA (P=0.004). Tukey (HSD: honestly significant difference) post hoc test indicated that difference in third molar angulation was statistically significant between first premolar extraction group with moderate anchorage and non-extraction group (P=0.007) and also between the first premolar extraction group with minimum anchorage and non-extraction group (P=0.024). CONCLUSION: The first premolar extraction groups with moderate and minimum anchorage may lead to more chance of third molar eruption and this can be helpful in borderline cases to consider third molar angulation as one of determining indicators to decide whether to extract or not to extract first premolars.


Asunto(s)
Tercer Molar/diagnóstico por imagen , Ortodoncia Correctiva , Extracción Dental , Adolescente , Diente Premolar/cirugía , Niño , Femenino , Humanos , Masculino , Tercer Molar/anatomía & histología , Radiografía Panorámica
15.
Oral Maxillofac Surg ; 22(2): 163-168, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29450664

RESUMEN

OBJECTIVES: The root anatomy and position of mandibular third molars are important factors in assessing the level of difficulty of surgical removal procedures. In this light, this study aims to identify the most frequent position and the root anatomy of mandibular third molars. METHODS: The study sample comprised 1205 mandibular third molars from 710 panoramic radiographs evaluated. Regarding the position, all of them were based on Pell and Gregory's and Winter's classifications. The root anatomy was classified according to the type and number of roots, as well as the presence of laceration, fusion, or divergence. Gender and the quadrant were also considered. Following an interexaminer analysis, a statistical analysis was performed using the Kappa test. RESULTS: The results showed that the IA (40.3%) and mesioangular (53.8%) position was predominant in mandibular third molars. Regarding the anatomy, the most common were two roots (98.3%), of the conical simple type (88.9%), with absence of laceration (89.2%), divergence (84%), and fusion (80%). CONCLUSION: The present study showed that the most prevalent mandibular third molar type in Brazilian patients was the IA and mesioangular position, with simple root anatomy. The result of this study can assist oral surgeons to better plan and assess the level of difficulty of surgical removal procedures.


Asunto(s)
Mandíbula/diagnóstico por imagen , Tercer Molar/anatomía & histología , Tercer Molar/diagnóstico por imagen , Radiografía Panorámica/métodos , Raíz del Diente/anatomía & histología , Raíz del Diente/diagnóstico por imagen , Brasil , Femenino , Humanos , Masculino , Extracción Dental
16.
Heredity (Edinb) ; 121(1): 1-11, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29302051

RESUMEN

Molar size in Mammals shows considerable disparity and exhibits variation similar to that predicted by the Inhibitory Cascade model. The importance of such developmental systems in favoring evolutionary trajectories is also underlined by the fact that this model can predict macroevolutionary patterns. Using backcross mice, we mapped QTL for molar sizes controlling for their sequential development. Genetic controls for upper and lower molars appear somewhat similar, and regions containing genes implied in dental defects drive this variation. We mapped three relationship QTLs (rQTL) modifying the control of the mesial molars on the focal third molar. These regions overlap Shh, Sostdc1, and Fst genes, which have pervasive roles in development and should be buffered against new variation. It has theoretically been shown that rQTL produces new variation channeled in the direction of adaptive changes. Our results provide evidence that evolutionary/disease patterns of tooth size variation could result from such a non-random generating process.


Asunto(s)
Mapeo Cromosómico , Estudios de Asociación Genética , Tercer Molar/anatomía & histología , Sitios de Carácter Cuantitativo , Carácter Cuantitativo Heredable , Algoritmos , Animales , Evolución Biológica , Femenino , Variación Genética , Escala de Lod , Masculino , Ratones , Modelos Teóricos
17.
Clin Oral Investig ; 22(7): 2505-2509, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29372444

RESUMEN

OBJECTIVES: The aim of the study was to evaluate the proximity of the mandibular third molar (M3) and the inferior alveolar canal (IAC) in a panoramic radiograph of 20-year-old subjects. The specific aim was to assess differences in this proximity over time. MATERIALS AND METHODS: Two similar samples of panoramic radiographs taken in a routine oral health examination with 20-year time interval were examined retrospectively and images with both mandibular M3s were included. The material consisted of 300 subjects (25% men, mean age 20.5 ± 0.6 years). The radiographic relationship between the mandibular M3 root and the IAC was assessed as follows: the M3 root was either apart from, tangential to, superimposed with, or inferior to the IAC. Differences between frequencies were tested using the chi-squared test. RESULTS: In the combined samples, only 16% of the M3s located apart from the IAC, 15% located tangential to, 61% superimposed with, and 8% inferior to the IAC. The proportion of the intimate locations had increased during the 20-year time interval from 79 to 88% (P < 0.01) and especially in females (P < 0.05). CONCLUSION: The vast majority of the mandibular M3s situated very close to the mandibular canal. CLINICAL RELEVANCE: Our results suggest that in the cohort of 20-year-old non-extraction subjects, most of the M3s are possibly at risk for inferior alveolar nerve injury at removal, as judged from the panoramic radiograph, and also the number of such teeth has increased over the 20-year period.


Asunto(s)
Mandíbula/anatomía & histología , Nervio Mandibular/anatomía & histología , Tercer Molar/anatomía & histología , Variación Anatómica , Femenino , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Nervio Mandibular/diagnóstico por imagen , Tercer Molar/diagnóstico por imagen , Radiografía Panorámica , Estudios Retrospectivos , Factores Sexuales , Adulto Joven
18.
Ann Anat ; 215: 83-92, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28954209

RESUMEN

INTRODUCTION: The aim of this study was to analyze the root canal morphology of maxillary third molars (MTMs) using micro-computed tomography (micro-CT). MATERIALS AND METHODS: Seventy-eight consecutively-extracted human MTMs were scanned using micro-CT (spatial resolution=13.68µm per pixel). Dedicated software (SkyScan®) was used to create virtual reconstructions and perform 3D-analysis. A range of anatomical features were assessed; externally (root number, length, fusion, curvature, apex), within the pulp chamber (distance between canal orifices, floor thickness) and within the root canal system (root canal number, classification, ramifications, isthmuses, apical constriction). RESULTS: The donor age ranged from 19 to 73 years (mean±SD 32.3±16.5years). MTMs possessed one or three roots, which principally curved buccally/palatally (75.9%), had 1-4 root canals and typically no apical constriction (84.4%). The average external root length was 11.89±1.53mm, while root canal length was 10.18±0.35mm. The root canal diameter 1mm from the apex was 0.37±0.23mm and negatively correlated with donor's age (r=-0.76; p=0.01), while pulp chamber thickness positively correlated with age (r=0.58; p=0.035). Significantly, furcation canals, canal loops and root canal calcifications were sporadic findings. CONCLUSIONS: In some cases the anatomy of MTMs may not be as complicated as previously documented, being similar to the reported anatomy of other maxillary molars. During root canal treatment of MTMs, the frequent deviation of the apical foramen from the radiographic apex should be considered, as should the absence of an apical constriction in the majority of cases. In addition, buccal/palatal root curvature, often undiagnosed radiographically, is the most common root curvature in MTMs.


Asunto(s)
Maxilar/anatomía & histología , Tercer Molar/anatomía & histología , Raíz del Diente/anatomía & histología , Adulto , Anciano , Femenino , Humanos , Masculino , Maxilar/diagnóstico por imagen , Persona de Mediana Edad , Tercer Molar/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Raíz del Diente/diagnóstico por imagen , Adulto Joven
19.
Surg Radiol Anat ; 40(6): 609-614, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29079941

RESUMEN

PURPOSE: The positional relationship between the mandibular canal and corresponding third molars is a key anatomic factor of inferior alveolar nerve (IAN) injury. The aim of the present study is to classify the anatomic three-dimensional relationship between the mandibular third molar and the mandibular canal on cone-beam computed tomography (CBCT) images. METHODS: This study used CBCT images to classify the positional relationship between the mandibular canal and corresponding third molars. CBCT images of 749 patients (1296 mandibular third molars) were analyzed to draw up a classification. RESULTS: On a total of 1296 third molars, the mandibular canal relative to the roots of the mandibular third molar was on the apical side (88.1%), followed by the buccal side (7.9%), the lingual side (3.5%), and then between the roots (0.5%). Ninety-five (7.1%) third molars had a close relation with the mandibular canal, while 1201 (92.7%) third molars had no direct contact. The percentage of the mandibular canal contacts with the mandibular third molar was higher when the mandibular canal was lingually positioned. CONCLUSIONS: The anatomic structures of the mandibular third molar and the mandibular canal may be helpful to make adequate surgical planning to avoid or reduce nerve involvement.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Mandíbula/anatomía & histología , Tercer Molar/anatomía & histología , Adulto , Anciano , Humanos , Imagenología Tridimensional , Mandíbula/diagnóstico por imagen , Nervio Mandibular/anatomía & histología , Nervio Mandibular/diagnóstico por imagen , Persona de Mediana Edad , Tercer Molar/diagnóstico por imagen , Adulto Joven
20.
J Am Dent Assoc ; 148(12): 903-912, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28965988

RESUMEN

BACKGROUND: Through a systematic literature review, the authors assess the effect of premolar extractions on third-molar (M3) eruption considering eruption rate, retromolar space, and molar angulation. TYPES OF STUDIES REVIEWED: The authors performed a systematic search using MEDLINE and Web of Science databases up through April 2017 to identify quality studies available comparing M3 eruption between a group with premolar extraction and a group without premolar extraction. RESULTS: Twelve comparative retrospective cohort studies met all the inclusion criteria. The authors found in 5 studies comparing the rate of M3 eruption that there were significantly higher results in the group with extractions. They found in 5 studies comparing the evolution of the retromolar space significantly higher results in the group with extractions. Lastly, concerning the uprighting of the M3 during treatment, the authors found only 2 studies showing significant differences between the 2 groups, each time in favor of the group with extractions. CONCLUSIONS AND PRACTICAL IMPLICATIONS: The dental literature on premolar extraction related to the eruption of the M3 is composed of average-quality retrospective studies. Premolar extraction significantly improves the chances of M3 eruption, but the level of evidence of comparative retrospective cohort studies is low. Clinicians must continue to rely on their judgment regarding premolar extraction on a case-by-case basis until the evidence is stronger. Retrospective studies with standardized protocols and more detailed methodologies are required to obtain higher levels of evidence.


Asunto(s)
Diente Premolar/cirugía , Tercer Molar/anatomía & histología , Tercer Molar/fisiopatología , Erupción Dental , Extracción Dental , Humanos , Ortodoncia Correctiva
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