ABSTRACT
Objectives: This study was aimed to measure and evaluate the morphological changes of the mandible, related to age and gender in partially edentulous and completely dentate subjects using panoramic radiographs. Methods: This study included a sample of 150 partially edentulous patients and 150 completely dentate patients enrolled in the College of Dentistry, King Saud Bin Abdulaziz University for Health Sciences between January 2015 and December 2018. Five mandibular morphological and anatomical parameters were measured using a Romexis software including; Condylar height. Gonial Angle, Ramus height, Antegonial notch depth and Ramal notch depth. Results: There was a significant difference (p=0.00) seen in the mean values of GA when comparing the partially edentulous (130.01 ± 7.79°) and completely dentate group (126.95 ± 6.64°). The mean values of GA were significantly larger among the younger age group (20-40) in both partially edentulous patients (131.58 ± 8.27°) and completely dentate group (127.17 ± 6.9°) (p<0.05). Conclusion: There was no relationship between the changes in the morphological measurements related to age and gender except for GA where younger subjects have higher GA values. Also, the mean values of GA were significantly higher in the partially edentulous group compared to completely dentate.
ABSTRACT
Quantitative trait loci (QTL) mapping analysis was performed for the mandible morphology in DDD.Cg-Ay/Sgn and C57BL/6J inbred mice. The size and shape of the mandible was analysed by landmark-based geometric morphometrics as the centroid size and principal components (PCs), respectively. The Ay allele at the agouti locus significantly reduced the mandible size in DDD/Sgn background, and substantially altered the mandible shape in both strain backgrounds. Single-QTL scans, by including the agouti locus genotype (Ay or non-Ay) as an additive covariate, identified three significant QTL for the centroid size on chromosomes 5, 6 and 17, along with four suggestive QTL on chromosomes 2, 12, 18 and 19. These QTLs explained 46.85% of the centroid size variation in F2 mice. When the F2Ay and F2 non-Ay mice were analysed separately, additional significant QTL were identified on chromosomes 12 and 15 in F2 non-Ay mice. Single-QTL scans also identified 15 significant QTL for the PC1, PC2 and PC3. When the agouti locus genotype was included as an interactive covariate, nine significant QTLs were identified. Unexpectedly, these agouti-interacting QTLs were identified for relatively minor PCs, for which no significant single-QTL were identified. Therefore, it was suggested that the alteration of the mandible shape in Ay mice was the consequence of interactions between the Ay allele and genes that themselves have relatively small phenotypic effect. Although further in vivo studies are required, we postulated Pkd1 as a possible candidate gene underlying QTL for the centroid size on chromosome 17.
ABSTRACT
El objetivo fue evaluar la relación de tejido óseo cortical presente en el sector anterior y posterior de sínfisis mandibular. Se seleccionaron 18 sujetos clase I dentaria y esqueletal, de ambos sexos, a partir de una tomografía computarizada de haz cónico para analizar morfométricamente en base a la posición de los dientes canino, incisivo lateral e incisivo central de ambos lados; se analizó la distancia vertical desde el ápice dentario hasta el punto más inferior del margen mandibular y la distancia anteroposterior en dos niveles inferiores del ápice (5 mm y 10 mm), donde se identificó el grosor de hueso cortical. El análisis de datos fue realizado con la prueba ANOVA considerando un valor de p<0,05. Se observó que el hueso cortical es de mayor tamaño en la cortical lingual que la cortical bucal con casi 1 mm de diferencia; la cortical inferior fue la de mayor tamaño; no se observaron diferencias en las mediciones realizadas para cada diente. Se concluye que el hueso cortical es de menor tamaño en el sector bucal al compararse con el lingual e inferior; se debe explorar los alcances quirúrgicos de este hallazgo.
The aim of this research was to evaluate the relation between the cortical bone in the anterior and posterior area of the mandible. Were selected 18 subjects, male and female, with dental and skeletal class I; in all of them was realized a cone beam computed tomography to make a morphometric analysis in agreed with de canine, lateral incisor and central incisor in the right and left, side. Was analyzed the distance in cortical area in a line from the dental apex and the horizontal line was obtained 5 mm and 10 mm from the dental apex; statistical significance was obtained by ANOVA considering a p value <0.05. Was observed that the cortical bone is thicker in the lingual side than the buccal side (1 mm diference approximately); the low cortical presented bigger size than anterior or posterior cortical bone; was not observed statistical differences between bone related to teeth. Its concluded that the buccal cortical bone is lower than lingual cortical bone; it is necessary an analysis about the surgical implications.
Subject(s)
Humans , Male , Female , Cortical Bone/anatomy & histology , Mandible/anatomy & histology , Tomography, X-Ray ComputedABSTRACT
El objetivo de este estudio fue evaluar la relación de tejido óseo cortical y esponjoso en el sector anterior de la mandíbula. Se seleccionaron 14 sujetos de ambos sexos para realizar el estudio piloto de este protocolo; en todos los sujetos se realizó un estudio con tomografía computarizada de haz cónico para realizar análisis morfométrico en base a la posición de los dientes canino, incisivo lateral e incisivo central de ambos lados; se analizó la distancia vertical desde el ápice dentario hasta el punto más inferior del margen mandibular y se analizó la distancia anteroposterior en dos niveles inferiores del ápice (5 mm y 10 mm); en estos niveles se identificó el tamaño de hueso cortical y el tamaño de hueso esponjoso. Se observó que el hueso cortical es de mayor tamaño en la cortical lingual que la cortical bucal, con casi 1 mm de diferencia; el hueso esponjoso fue similar a la sumatoria de ambos huesos corticales (5 mm aproximadamente) en las áreas evaluadas. Se concluye que el hueso cortical es menor en el sector bucal al compararse con el lingual; la distancia vertical desde el ápice dentario hasta el margen mandibular fue de 16,5 y 21,05 mm.
The aim of this research was to evaluate the relation between the cortical and cancellous bone in the anterior area of the mandible. Were selected 14 subjects, male and female, to make the pilot study with this protocol; in all of them was realized a cone beam computed tomography to make a morphometric analysis in agreed with de canine, lateral incisor and central incisor of the both, right and left, side. Was analyzed the distance between the apex of the tooth to the inferior point of the cortical bone in the marginal area and in 5 and 10 mm lower of the dental apex. In these levels were identified the cortical bone size and cancellous bone size. Was observed that the cortical bone is thicker in the lingual side than the buccal side (1 mm diference approximately); the cancellous bone size is like the lingual and buccal cortical size (5 mm approximately) in the evaluated areas. Its concluded that the buccal cortical bone is lower than lingual cortical bone; the vertical distance between the apex and the basilar area is close to 16.5 and 21.05 mm.