Artículos de Investigación

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Author: search.filters.author.Carlos SalamancaLanguage: search.filters.language.English

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    Item type:Publication,
    A <i>SHMT1</i> variant decreases the risk of nonsyndromic cleft lip with or without cleft palate in Chile
    (2019)
    Carlos Salamanca
    ;
    Patricio González‐Hormazábal
    ;
    Andrea S. Recabarren
    ;
    Pamela A. Recabarren
    ;
    Roberto Pantoja
    <jats:title>Abstract</jats:title><jats:sec><jats:title>Objective</jats:title><jats:p>To assess the association between polymorphic variants from <jats:italic>SHMT1</jats:italic> and <jats:italic>MTHFS</jats:italic> genes, involved in the cytoplasmic futile folate cycle, and the risk of nonsyndromic cleft lip with or without cleft palate (NSCL/P) in the Chilean population.</jats:p></jats:sec><jats:sec><jats:title>Subjects and Methods</jats:title><jats:p>In a sample of 139 Chilean NSCL/P cases and 278 controls, we obtained the genotypes for nine variants of <jats:italic>SHMT1</jats:italic> and <jats:italic>MTHFS</jats:italic> and the association between them and the phenotype was evaluated using odds ratios (OR) in additive (allele), dominant, and recessive models.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>After correction for multiple comparisons, only the variant rs1979277 (G &gt; A; p.Leu474Phe) from <jats:italic>SHMT1</jats:italic> showed a significant and protective effect for additive (OR 0.60; 95% CI 0.42–0.86; <jats:italic>p</jats:italic> = .0054, <jats:italic>q</jats:italic> = 0.0488) and dominant models (OR 0.48; 95% CI 0.29–0.75; <jats:italic>p</jats:italic> = .0009; <jats:italic>q</jats:italic> = 0.0081). Our bioinformatic prediction plus functional evidence from previous reports demonstrate that the A allele for this missense variant decreases the enzymatic activity.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Owing to the rs1979277 A allele, which reduces the cytoplasmic SHMT activity and has a higher frequency in controls than in NSCL/P cases, we hypothesized that a low enzyme activity may increase the cytoplasmic concentration of folates and, therefore, explain the protective role against OFCs.</jats:p></jats:sec>
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    Item type:Publication,
    Influence of transmucosal height in abutments of single and multiple implant-supported prostheses: a non-linear three-dimensional finite element analysis
    (2018-01-10)
    Eduardo Borie
    ;
    Eduardo Da Silva Leal
    ;
    Iara Augusta Orsi
    ;
    Carlos Salamanca
    ;
    Fernando José Dias
    The aim of this study was to analyze the influence of three different transmucosal heights of the abutments in single and multiple implant-supported prostheses through the finite element method. External hexagon implants, MicroUnit, and EsthetiCone abutments were scanned and placed in an edentulous maxillary model obtained from a tomography database. The simulations were divided into two groups: (1) one implant with 3.75 × 10 mm placed in the upper central incisor, simulating a single implant-supported fixed prosthesis with an EsthetiCone abutment; and (2) two implants with 3.75 × 10 mm placed in the upper lateral incisors with MicroUnit abutments, simulating a multiple implant-supported prosthesis. Subsequently, each group was subdivided into three models according to the transmucosal height (1, 2, and 3 mm). A static oblique load at an angle of 45 degrees to the long axis of the implant in palatal-buccal direction of 150 and 75 N was applied for multiple and single implant-supported prosthesis, respectively. The implants and abutments were assessed according to the equivalent Von Mises stress analyses while the bone and ceramics were analyzed through maximum and minimum principal stresses. The total deformation values increased in all models, while the transmucosal height was augmented. The transmucosal height of the abutments influences the stress values at the bone, ceramics, implants, and abutments of both the single and multiple implant-supported prostheses, with the transmucosal height of 1 mm showing the lowest stress values.