Libros

Aim: The aim of the present study was to verify the possibility of obtaining an optimized prosthetic substructure using generic software, respecting the distribution loads and forces involved. What is considered to be original and innovative in this study is the possibility of designing the prosthetic substructure on the basis of the individual patient’s chewing biomechanics, with the purpose of obtaining an even greater efficiency than a prosthesis designed according to a traditional method. Materials and methods: The starting standard triangulation language (STL) file was processed with Rhinoceros software and the tOpos plugin. It was decided to submit the entire prosthetic solution, intended as total volume, to structural analysis and topological optimization because the entire prosthesis is subjected to load during the chewing act. The software program was provided with information on the material, modulus, and direction of the applied forces. The objective was to optimize stiffness by maximizing volume. Results: The volume of the final structure was 2% compared with the starting model and was a completely different design compared with the traditional model. This new design was characterized by trabeculations that reflect the normal bone architecture. The material was distributed on the basis of the load points as well as the direction and modulus of the applied force. Conclusions: After assessing the applicability of the proposed workflow and the results obtained thus far, the most important clinical implication is represented by the greater efficiency and the same resistance of the prosthesis obtained with topological optimization compared with that obtained with the traditional method. Palabras clave: prosthetic substructure, structural analysis, finite element method (FEM), finite element analysis (FEA), chewing biomechanics, prosthetic complications, CAD/CAM technology

Aims: To evaluate the efficacy of melatonin compared to placebo in reducing pain associated with burning mouth syndrome (BMS), as well as side effects of treatment and effects on sleep quality, anxiety, and serum and salivary melatonin levels. Methods: In this triple-blind, randomized clinical trial, 20 BMS patients (mean age ± standard deviation: 64.4 ± 11.5 years; range: 35 to 82 years) were enrolled to receive melatonin (12 mg/day) or placebo for 8 weeks in a crossover design. After treatment, changes in pain from baseline were ascertained by patient self-assessment with a verbal category scale and a visual analog scale. Secondary outcomes included evaluation of changes in sleep quality and anxiety. Data were subjected to analysis of variance (ANOVA), Fisher exact test, paired t test, Wilcoxon signed rank test, or chi-square test, as appropriate. Results: Melatonin was not superior to placebo in reducing pain. Melatonin significantly improved anxiety scores, though without strong clinical relevance. Independent of treatment, sleep quality did not significantly change during the trial, although melatonin slightly increased the number of hours slept. After active treatment, the mean ± standard error serum melatonin level peaked at 1,520 ± 646 pg/mL. A generally safe pharmacologic profile of melatonin was observed, and the placebo and melatonin treatments resulted in similar adverse effects. Conclusion: Within the limitations of this study, melatonin did not exhibit higher efficacy than placebo in relieving pain in BMS patients. Palabras clave: anxiety, indoleamine, orofacial pain, sleep, stomatodynia

Impacted maxillary canine teeth commonly occur in the general population. The traditional therapeutic approach comprises fenestration and orthodontic traction; however, if traction is not feasible or the patient refuses orthodontic treatment, an alternative solution is to remove the impacted tooth and immediately place an implant. This technical note describes a novel surgical approach to rehabilitation after impacted canine tooth removal, entailing immediate placement of a long implant in combination with regenerative materials and a barrier. Of note, this procedure preserves the apical ridge bone crest, allowing implant anchorage and primary stability to be achieved. Palabras clave: immediate dental implants, impacted tooth, oral surgery

Purpose: The microbial colonization of new ceramic materials developed for abutment manufacturing was assessed. Materials and Methods: The materials used in these experiments were disks of "asfired" and "rectified" ceramic material made of tetragonal zirconia polycrystals stabilized with yttrium (Y-TZP) and commercially pure grade 2 titanium (Ti) with corresponding eluates. They were tested in vitro with the following bacteria: Streptococcus mutans, S sanguis, Actinomyces viscosus, A naeslundii, and Porphyromonas gingivalis. Proliferation was evaluated on plates by inhibitory halos around pits, previously inoculated with eluates obtained from the materials. Bacterial adhesion on materials was quantified by spectrophotometric evaluation of the slime production by the same bacteria. Moreover, early bacterial adhesion was evaluated in human volunteers and observed with SEM. Results: No inhibition of bacterial proliferation using eluates was observed. In vitro as-fired and rectified Y-TZP showed significantly more adherent S mutans than did Ti disks, while S sanguis seemed to adhere easily to Ti specimens. No differences were noted for Actinomyces spp and P gingivalis. In vivo Y-TZP accumulated fewer bacteria than Ti in terms of the total number of bacteria and presence of potential putative pathogens such as rods. No differences were observed between rectified and as-fired Y-TZP. Discussion: Overall, Y-TZP accumulates fewer bacteria than Ti. Conclusion: Y-TZP may be considered as a promising material for abutment manufacturing.