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Insertion and reinsertion of the screws of the vertebral fixation system used in the present study reduced the insertion torque and screw purchase.

Purpose To experimentally study the influence of pilot hole diameter (smaller than or equal to the internal (core) diameter of the screw) on biomechanical (insertion torque and pullout strength) and histomorphometric parameters of screw-bone interface in the acute phase and 8 weeks after pedicle screw insertion. Methods Fifteen sheep were operated upon and pedicle screws inserted in the L1-L3 pedicles bilaterally. The pilot hole was smaller (2.0 mm) than the internal diameter (core) of the screw on the left side pedicle and equal (2.8 mm) to the internal diameter (core) of the screw on the right side pedicle. Ten animals were sacrificed immediately (five animals were assigned to pullout strength tests and five animals were used for histomorphometric bone-screw interface evaluation). Five animals were sacrificed 8 weeks after pedicle screw insertion for histomorphometric bonescrew interface evaluation. Results The insertion torque and pullout strength were significantly greater in pedicle screws inserted into pilot holes smaller than internal (core) diameter of the screw. Histomorphometric evaluation of bone-screw interface showed that the percentage of bone-implant contact, the area of bone inside the screw thread and the area of bone outside the screw thread were significantly higher for pilot holes smaller than the internal (core) diameter of the screw immediately after insertion and after 8 weeks. Conclusion A pilot diameter smaller than the internal (core) diameter of the screw improved the insertion torque and pullout strength immediately after screw insertion as well the pedicle screw-bone interface contact immediately and 8 weeks after screw placement in sheep with good bone mineral density.

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Objective:To assess the effect of chronic alcohol consumption on the longitudinal growth of the tibia and bone quality parameters in young rats under an experimental setup.METHODS:The control (n=10) rats received only water. The ethanol (n=10) rats received ethyl alcohol at concentrations established in the protocol for the induction of chronic alcohol consumption. The blood samples were immediately collected via cardiac puncture and processed to evaluate the levels of alkaline phosphatase by automated spectrophotometry. Following blood sample collection, both tibias were dissected, and weighed; the tibial length was measured., and the samples were stored in a freezer for future analysis of the bone mineral content and mechanical resistance, known as maximal load and stiffness.RESULTS:Compromised bone health, with a 35.3% decrease in the serum alkaline phosphatase levels (p < 0.01), a 10% decrease in the tibial mass (p < 0.05), and a 5.3% decrease in the tibial length (p < 0.0001) were noted. Furthermore, a 10% decrease in the bone mineral density was observed (p < 0.01), which led to a 17.2% decrease in the maximum strength (p < 0.01) and 22.6% decrease in stiffness (p < 0.001).CONCLUSION:Chronic consumption of alcohol affected the bones of young rats, making them weaker and osteopenic. In addition, the long bones were shorter, suggesting interference with growth. Level of Evidence III, Case Control Study.

The aging process affects the entire human body, including the stomatognathic system, and can trigger not only occlusal but also postural imbalances involving other muscular chains. Hippotherapy has been used to promote cervical, postural, and balance control in individuals with diverse impairments. The present study used electromyography to evaluate the masseter and temporal muscles in an elderly population pre-and post-hippotherapy. Participants included 17 individuals, mean age 66,5±7 years. Electromyographic recording of the bilateral masseter and temporal muscles was performed during the postural resting condition and activities that involved the active participation of these muscles in different conditions. The practitioner performed no other type of activity or exercise during the intervention because the objective is to evaluate the effect of the three-dimensional movement provided by the horse. Raw electromyographic data were tabulated using commercially available software (IBM ® SPSS ® Statistics 234.0) and subjected to statistical analysis, in which p � 0.05 was considered to be statistically significant. Post-hippotherapy, there was lower electromyographic activity for the masseter and temporalis muscles in all the static mandibular tasks, with significant effect for time for the right temporal muscle (p = 0.038), the left temporal muscle (p = 0.028) and in the all dynamic mandibular tasks for the left temporal muscle (p = 0.025) and the left masseter muscle (p = 0.027). Hippotherapy promotes a reduction in the myoelectric activity of the masticatory muscles of elderly individuals.

OBJECTIVES:To evaluate the influence of secondhand cigarette smoke exposure on longitudinal growth of the tibia of growing rats and some parameters of bone quality.METHODS:Forty female rats were randomly divided into four groups: control: rats were sham exposed; 30 days: rats were exposed to tobacco smoke for 30 days; 45 days: rats were exposed to tobacco smoke for 45 days; and 60 days: rats were exposed to tobacco smoke for 60 days. Blood samples were collected to evaluate the levels of cotinine and alkaline phosphatase. Both tibias were dissected and weighed; the lengths were measured, and the bones were then stored in a freezer for analysis of bone mineral content and mechanical resistance (maximal load and stiffness).RESULTS:Exposure of rats to tobacco smoke significantly compromised bone health, suggesting that the harmful effects may be time dependent. Harmful effects on bone growth were detected and were more pronounced at 60-day follow-ups with a 41.8% reduction in alkaline phosphatase levels (p<0.01) and a decrease of 11.25% in tibia length (p<0.001). Furthermore, a 41.5% decrease in bone mineral density was observed (p<0.001), leading to a 42.8% reduction in maximum strength (p<0.001) and a 56.7% reduction in stiffness (p<0.001).CONCLUSION:Second hand cigarette smoke exposure in rats affected bones that were weaker, deforming them and making them osteopenic. Additionally, the long bone was shorter, suggesting interference with growth. Such events seem to be related to time of exposure.