BackgroundThe pullout strength of pedicle screws is influenced by many factors, including diameter of the screws, implant design, and augmentation with bone cement such as PMMA. In the present study, the pullout strength of an innovative fenestrated screw augmented with PMMA was investigated and was compared to unaugmented fenestrated, standard and dual outer diameter screw.MethodsTwenty four thoracolumbar vertebrae (T10-L5, age 60 to 70 years) from three cadavers were implanted with the four different pedicle screws. Twelve screws of each type were instrumented into either left or right pedicle with standard screw paired with unaugmented and dual outer diameter screw paired with augmented fenestrated screw in any given vertebra. Axial pullout testing was conducted at a rate of 5 mm/min. Force to failure (Newtons) for each pedicle screw was recorded.ResultsThe augmented fenestrated screws had the highest pullout strength, which represented an average increase of 149%, 141%, and 78% in comparison to unaugmented, standard, and dual outer diameter screws, respectively. Pullout strength of unaugmented screws was comparable to that of standard screws, however it was significantly lower than dual outer diameter screws.ConclusionsFenestrated screws augmented with PMMA improve the fixation strength and result in significantly higher pullout strength compared to dual outer diameter, standard and unaugmented fenestrated screws. Screws with dual outer diameter provided enhanced bone-screw purchase and may be considered as an alternative technique to increase the bone-screw interface in cases where augmentation using bone cement is not feasible. Unaugmented screws can be left in the pedicle even without cement and provide similar pullout strength to standard screws.
The objective of this study was to determine the prevalence of malocclusion among school children of Bangalore city, India during their mixed dentition period. The sample consisted of 745 children (388 males and 357 females) in the age group of 8-12 years randomly selected from twelve different schools in Bangalore city. The subjects were randomly selected, and none had received previous orthodontic treatment. Occlusal anteroposterior relationships were assessed based on the Angle classification. Also various malocclusion features associated with class I malocclusion according to Dewey’s modification of Angle’s classification were assessed. The results showed that about 71% of the subjects had malocclusion. Class I malocclusion constituted the major proportion of malocclusion which was found in 62% of the studied population. No significant difference was found between boys and girls neither in the overall prevalence of malocclusion nor in various forms of malocclusion. Crowded incisors was found to be most ommon finding in subjects with class I malocclusion. A number of studies have been conducted to determine the prevalence of malocclusion among Indian children and it has been reported that the results range from a value as low as 19.6% (Miglani DC, Chennai 1961) to as high as 90% (Sidhu SS, Delhi). This varied range emphasizes the need to standardize criteria for assessing malocclusion.
The aim of the present study was to evaluate cephalometrically the treatment effects of preorthodontic trainer on dentoskeletal components in individuals showing class II division I malocclusion. This study comprised of 50 class II div. I patients (20 test patients and 30 controls) in the age group of 8-12 years. The test group was treated with a preorthodontic trainer for a period of 15 months. Standardized lateral cephalograms of both groups were taken before and after the treatment period. The cephalograms were then evaluated to determine the skeletal and dental changes in the course of treatment and then compared with the normative growth data to eliminate the possible growth effects. The readings were tabulated and subjected to statistical analysis. The results of the study after excluding the changes due to growth showed reduction in ANB and OP-SN values, indicating a significant reduction in the skeletal class II relationship. An upward cant of the occlusal plane in the treatment group was noted, probably due to the forward rotation of mandible. A significant increase in the vertical dimensions of the face in general and the mandible in particular was observed with the use of preorthodontic trainer. A significant reduction in the overjet and an increase in the inclination of mandibular incisor (L1-NB deg) were noted in the treatment group when compared with control group. It can be concluded that class II corrections can be achieved with the preorthodontic trainer appliance, which appears to have mostly dentoalveolar effects with smaller but significant skeletal effects.
Background: Restricted mouth opening is a common complaint in patients suffering from temporomandibular joint disorders, ankylosis, impaired masticatory muscle function, rheumatic disease, infection, or malignancy. As with any disease, the aim of treatment of disorders affecting mouth opening is to restore the mouth opening to its normal value. It is thus of paramount importance to determine the normal value. Objective: To establish the normal range of maximal incisal opening (MIO) in children aged 4 to 15 years and to investigate the correlation between MIO and age, gender, height, and body weight. Materials and Methods: Six hundred and two children from various schools in Bengaluru, India, participated in the study. The children were divided into the following age groups: 4–5, 6–7, 8–9, 10–11, 12–13, and 14–15 years. MIO for the children was recorded using Therabite ® scale. The measurements of MIO were then correlated with gender, body weight, and height of the children in different age groups. Results: It was observed that MIO gradually increased with age with a mean MIO of 41.34 mm at 4–5 years to a mean MIO of 51.73 mm at 14–15 years. The mean MIO value for males (48.90 ± 6.49 mm) was found to be higher when compared to that of females (46.17 ± 5.58 mm). The results indicated a strong positive correlation of MIO with height and weight. Conclusion: MIO gradually increased with age in both the genders, and a strong positive correlation of MIO with height and weight was observed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.