High doses of zoledronic acid induce differential effects on femur and jawbone microstructure.

OBJECTIVES: The aim of this study is to investigate the long-term effects on jaw and femur bone induced by oncologic doses of zoledronic acid in a young rat model. MATERIAL AND METHODS: Six 12-week-old male Wistar rats received zoledronic acid (0.6 mg/kg) and six control rats received saline solution in the same volume. Compounds were administered intraperitoneally in five doses every 28 days. Euthanasia was performed 150 days after therapy onset. After animal sacrifice, their mandibles and femurs were scanned ex vivo using a high-resolution (14 µm) micro-computed tomography. Morphometric bone parameters were calculated using CT-Analyzer (Bruker, Belgium) between the first and second mandibular molars and in the distal femur metaphysis and epiphysis. RESULTS: The treatment group as compared to the controls showed a significantly (p < .05) increased bone quantity (↑BV/TV, ↓Po[Tot], ↑Tb.Th), bone density (↑TMD, ↑BMD), and osteosclerosis of the trabecular bone (↓Tb.Sp, ↓Conn.Dn, ↓Tb.Pf, ↓SMI) in all anatomical sites. Bone remodeling suppression due to zoledronic acid treatment was more pronounced (p < .05) in the femoral metaphysis relative to the mandible and epiphysis. The exploratory linear discriminant analysis showed that for the mandible, it was mainly the bone quantity-related morphometric indices (BV/TV and Tb.Th), while for the femoral epiphysis and metaphysis, it was bone structure-related (Tb.Pf and Tb.N), which are of primary importance to study the treatment effect. CONCLUSION: High doses of bisphosphonates can differently affect the bone quantity, density, and structure in long bones and jawbones. In the metaphysis, bone changes were primarily concentrated in the region of the growth plate. Future studies may consider the use of bone morphometric indices to evaluate the effect of bisphosphonates.

Bone traits and gastrointestinal tract parameters of piglets fed cholecalciferol and 1, 25-dihydroxycholecalciferol glycoside

The objective of this study was to evaluate the cholecalciferol and 1,25-dihydroxycholecalciferol glycoside supplementation in piglet diet on organ biometry and physicochemical composition, pH of the digestive tract contents, and bone traits. A total of 128 entire male piglets (21 days-old, 6.82±0.38 kg body weight) were distributed in a completely randomized block design with eight replications and four animals per experimental unit. The treatments were composed of a diet 100/0 = 100% of the vitamin D supplemented with cholecalciferol; 50/50 = 50% supplemented with cholecalciferol + 0.25 µg of 1,25(OH)2 D3 glycoside; 25/75 = 25% supplemented with cholecalciferol + 0.375 µg of 1,25(OH)2 D3 glycoside; and 0/100 = 0.50 µg of 1,25(OH)2 D3 glycoside. The results indicated that piglets fed 100/0 showed an increase in spleen weight compared with those fed 0/100 and greater heart dry matter than piglets fed the 50/50 diet. Phosphorus concentration in the spleen was higher in piglets that received 25/75 when compared with those that received the 100/0 and 0/100 diets. Piglets that received the 0/100 diet showed higher pH of the stomach contents, but showed reduced pH of the contents of the jejunum and ileum. The width of the epiphysis and diaphysis was greater when piglets consumed the 50/50 treatment; however, a lower epiphysis height was observed. The use of 1,25(OH)2 D3 glycoside alone in piglet diets does not negatively influence the pH of the gastrointestinal tract and organ physicochemical composition. In addition, the use of diets with 1,25(OH)2 D3 glycoside as a replacement for cholecalciferol reduces spleen weight and promotes improvements in bone development.

Morphometric evaluation of bone regeneration in segmental mandibular bone defects filled with bovine bone xenografts in a split-mouth rabbit model.

BACKGROUND: Bovine bone grafts have been widely used in dentistry for guided tissue regeneration and can support new bone formation in direct contact with the graft. The aim of this study was to compare the morphometric and bone density changes after using two different bovine bone graft blocks in segmental osseous defects in the mandible of rabbits following different postoperative periods. MATERIAL AND METHODS: Critical size segmental defects were surgically created bilaterally in the jaw of 18 rabbits. The defects were filled with either deproteinized bovine bone mineral with 10% collagen (DBBM-C; BioOss Collagen®), lyophilized bovine medullary bone (LBMB; Orthogen®), or left untreated according to a split-mouth design. Animals were sacrificed after 3 or 6 months of healing. The hemimandibles were scanned ex vivo using a high-resolution (19 µm) microcomputed tomography. Morphometric and bone density parameters were calculated in the region of the defect using CT-Analyser (Bruker). Initial graft blocks were used as baseline. RESULTS: DBBM-C presented a denser microarchitecture, in comparison to LBMB at baseline. DBBM-C and LBMB grafted regions showed a similar progressive remodeling, with a significant decrease in structure complexity and maintenance of bone volume fraction during the postoperative follow-up periods. Both graft materials showed an enhanced bone replacement and more complex structure compared to untreated defects. The apparent fusion between the graft and host bone was observed only in the defects filled with LBMB. CONCLUSION: LBMB grafts showed a similar behavior as DBBM-C regarding structural remodeling. In LBMB samples, apparent integration between the host bone and the graft was present.

Craniofacial morphometry for craniofacial implant / Morfometría craneofacial para implante craneofacial

Craniofacial implants are being increasingly used to treat patients with sequelae of oncological resections, trauma, and congenital deficiencies, among other issues. The aim of this investigation was to establish the minimum and maximum bone dimensions present in the most used places for the insertion of craniofacial implants. A descriptive study was designed analyzing 40 human skulls using cone-beam computed tomography; in the volumetric reconstruction the points most often used in clinical investigations for the insertion of implants were selected, representing the orbital, perinasal, zygomatic bone and periauricular regions, measuring the distance between the cortical bones on the sagittal, axial and coronal planes; comparisons between gender and with other investigations with a similar aim were also made. In the supraorbital area, values of 7.92+/-1.82 mm were found and in the lateral area values of 7.54+/-0.98 mm, allowing the placement of implants 5 or 6 mm in length. In the area of the zygomatic bone, dimensions of 10.4+/-2.35 mm were obtained, allowing the placement of implants 8 mm in length. In the periauricular area values were obtained of 2.93+/-0.55 mm in the superior region and 3.1+/-0.7 mm in the inferior region, whereas in the perinasal area implants 4 mm in length can be placed. We concluded that the craniomaxillofacial bone structure presents acceptable widths for the installation of implants; the periauricular region presents lower dimensions, with the possibility of intracranial communication in areas above the external auditory meatus...

Los implantes craneofaciales están siendo cada vez más utilizado para tratar a pacientes con secuelas de resecciones oncológicas, traumatismos, y deficiencias congénitas, entre otras. El objetivo de esta investigación fue establecer las dimensiones óseas mínimas y máximas presentes en los lugares más utilizados para la inserción de implantes craneofaciales. Se diseño un estudio descriptivo que analizó 40 cráneos humanos utilizando cono Tomografía computarizada Cone-Beam; en la reconstrucción volumétrica fueron seleccionados los puntos más utilizados en las investigaciones clínicas para la inserción de implantes, que representan la orbital, hueso perinasal, hueso cigomático y regiones periauriculares. La medición de la distancia entre los huesos corticales en los planos sagital, axial y coronal, y las comparaciones entre el sexo y otras investigaciones con el mismo objetivo fueron realizadas. En el área supraorbital, se encontraron valores de 7,92 +/- 1,82 mm y en las áreas laterales de 7,54 +/- 0,98 mm, lo que permite la colocación de implantes de 5 o 6 mm de longitud. En el área del hueso cigomático se obtuvieron,dimensiones de 10,4 +/- 2,35 mm, permitiendo la colocación de los implantes de 8 mm de longitud. En la región periauricular se obtuvieron valores de 2,93 +/- 0,55 mm en la región superior y 3,1 +/- 0,7 mm en la región inferior, mientras que en lo zona perinasal se puede colocar implantes de 4 mm de longitud. Llegamos a la conclusión de que la estructura de los huesos craneomaxilofaciales presenta anchos aceptables para la instalación de implantes; la región periauricular presenta menores dimensiones, con la posibilidad de comunicación intracraneal en zonas sobre el meato auditivo externo...

Intraobserver and interobserver reliability of radial torsion angle measurements by a new and alternative method with computed tomography

OBJECTIVE: To evaluate the intraobserver and interobserver reliability of radial torsion angle measurement using computed tomography. METHODS: Twelve pairs of cadaver radii and 116 forearms from 58 healthy volunteers were evaluated using axial computed tomography sections measured at the level of the bicipital tuberosity and the subchondral region of the radius. During digital imaging, the angle was formed by two lines, one diametrically perpendicular to the radial tubercle and the other tangential to the volar rim of the distal joint surface. Measurements were performed twice each by three observers. RESULTS: In cadaveric bones, the mean radial torsion angle was 1.48º (-6º - 9º) on the right and 1.62º (-6 º - 8º) on the left, with a mean difference between the right and left sides of 1.61º (0º - 8º). In volunteers, the mean radial torsion angle was 3.00° (-17° - 17°) on the right and 2.91° (-16°- 15°) on the left, with a mean difference between the sides of 1.58º (0º - 7º). There was no significant difference between each side. The interobserver correlation coefficient for the cadaver radii measurements was 0.88 (0.72 - 0.96) and 0.81 (0.58 - 0.93) for the right and left radius, respectively, while for the volunteers, the difference was 0.84 (0.77 - 0.90) and 0.83 (0.75 - 0.89), respectively. Intraobserver reliability was high. CONCLUSION: The described method is reproducible and applicable even when the radial tubercle has a rounded contour.