Although composite resin core is used with various types of prefabricated posts, it remains unclear which kind of material is most suitable for the post. The aim of this study was to evaluate the influence of prefabricated posts on the stress distribution within the root by finite element analysis. Posts and cores were built up with composite resin and four types of prefabricated posts: two types of glass fiber posts (GFP1, GFP2) with low and high Young's moduli, a titanium post (TIP), and a stainless steel post (SSP). In all models, stress distribution during function was calculated. There were differences in stress concentration at the root around the end of posts. The magnitudes of stress for GFP1, GFP2, TIP, and STP were 8.7, 9.3, 11.7, and 13.9 MPa respectively. Given the results obtained, GFP1 was the most suitable material for post fabrication since this model showed a lower stress value. It would therefore mean a lower possibility of root fracture.
3D printing with controlled microarchitectures has gained traction in a wide variety of fields, including bone tissue engineering, because it represents an exciting alternative for the synthesis of new scaffolds due to its rapid manufacturing process, high precision, cost-effectiveness, and ease of use. Thus, this study is aimed at evaluating the biocompatibility response of a 3D-printed tubular scaffold coated by a layer of 7% PLA nanofibers. The morphology, structure, and chemical composition of the 3D-printed tubular scaffold were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and surface property analysis by profilometry. The biocompatibility response of the scaffold was assessed by cell adhesion, proliferation, and cell-material interactions of human fetal osteoblasts. Our results showed that 3D printing allowed obtaining similar and reproducible structures and the biocompatibility assays showed that nanofiber coating of the surface of the 3D tubular scaffold promoted an improvement on cell attachment, proliferation, and the morphology of osteoblast cells when compared with a noncoated scaffold. In conclusion, the surface of the 3D-printed tubular scaffold could be improved by the deposition of a nanofiber layer to render a more mimetic and active topography with excellent cellular biocompatibility for bone tissue applications.
The aim of this study was to use the Hiroshima University - Dental Behavioral Inventory (HU-DBI) to compare oral health attitudes and behavior of dental and civil engineering students in Colombia. The HU-DBI’s survey consisting of twenty dichotomous responses (agree-disagree) regarding tooth brushing, was completed at University Antonio Narino for the dental students and the University of Cauca for the civil engineering students. The Spanish version of the HU-DBI questionnaire was taken by 182 of 247 dental students and 411 of 762 engineering students. The data was-statistically analyzed by the chi-square test and backward logistic regression. Compared to the engineering students, the dental students were more likely to agree with questions such as “I am bothered by the color of my gums”(OR = 2.2, 95% CI: 1.3-3.7),“I think I can clean my teeth well without using toothpaste” (OR = 3.0, 95% CI: 1.5-5.9), “I have used a dye to see how clean my teeth are” (OR = 2.9, 95% CI: 1.9-4.3), and “I have had my dentist tell me that I brush very well” (OR = 2.0, 95% CI: 1.3-3.1). The dental education curriculum in a dental school compared to a civil engineering school in Colombia indicated that a three-phase curriculum in didactics and clinics increased oral health attitudes and behavior from entry to graduation. (J Oral Sci 55, 23-28, 2013)
The aim of this study was to compare three types of post and core systems by analyzing the stress magnitude within the root. To this end, two-dimensional photoelastic simulation models of endodontically treated maxillary central incisors were fabricated. Three different types of post and core systems were selected for this study: composite resin post and core, composite resin core in combination with a glass fiber post, and conventional cast metal post and core. The fabricated models were observed in a transmission polariscope with the same loading force (400 N) on 45° palatal direction and the fringe orders registered were thereby analyzed. Results obtained in this study suggested that abutment build-up using composite resin core in combination with a glass fiber post model produced the lowest stress concentration and is hence effective in preventing stress concentration in the case of restored endodontically treated teeth.
1 September 2016 in Journal of Cranio-Maxillofacial Surgery