Artículos de Investigación

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Author: search.filters.author.María Florencia LezcanoLanguage: search.filters.language.English

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    Characteristics of Mandibular Movement and Mastication in Older Adults with Removable Dental Prostheses: Three-Dimensional Analysis
    (2020)
    Paloma Rivera
    ;
    Constanza Farfán
    ;
    Alain Arias
    ;
    María Florencia Lezcano
    ;
    Fernando José Dias
    Aging is a dynamic process that includes various alterations in the oral cavity, with tooth loss being the most frequent. Rehabilitative treatment may include removable or fixed prostheses and implants. The aim of this study was to describe the geometric (trajectory, ranges, areas) and kinematic (speed) characteristics of the mandibular and masticatory movements threedimensionally in participants with dental prostheses. A sample of 10 participants with removable prosthetic rehabilitation was divided into three groups (complete, atypical and overdenture) the characteristics of mandibular movements bordering and chewing with 3D Electromagnetic Articulography were measured. The Posselt polygonin was obtained, the frontal and sagittal plans, its areas, trajectories and ranges are analyzed. The masticatory movements were analyzed in the area of each cycle, the frequency, the speed and the reason between the masticatory cycle and the bordering movements, no significant differences between the groups. Subjects with dental prostheses, regardless of the type, they showed low of motion (border and functional) compared to dentate subjects with no functional alterations whose values have been reported in the literature. The subjects with overdenture have values closer to what is described for young dentate subjects.
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    Mastication as a protective factor of the cognitive decline in adults: A qualitative systematic review
    (2019)
    Priscila Chuhuaicura
    ;
    Fernando José Dias
    ;
    Alain Arias
    ;
    María Florencia Lezcano
    ;
    Ramón Fuentes
    Introduction: A relationship between masticatory function and cognition has been reported. It is proposed that mastication changes the blood flow stimulating the perfusion/oxygenation of the brain. This literature review analysed the relation between mastication as a protective factor of the cognitive decline and the changes produced at brain level in adults associated with the brain blood flow. Materials and methods: A systematic review was performed according to the 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' (PRISMA) criteria in PubMed/MEDLINE, Web of Science, Scopus and Embase. Primary studies were included with no limit on the publication date, conducted on humans, and that established a relation between mastication, brain blood flow and cognitive functions in adult patients. Results: Nine clinical descriptive studies were selected and qualitatively analysed. The collected data suggest the greatest brain areas activated during mastication were the frontotemporal cortex, the caudate nucleus and the thalamus, revealing a positive correlation between chewing intensity and perfusion of the principal trigeminal nucleus. The increase in cerebral blood flow was measured by a local vasodilator effect resulting in increased neuronal metabolism in the region linked to learning and memory. In addition, partially edentulous participants had a marked prefrontal deactivation when they chewed without a prosthesis and presented a decrease in masticatory activity. Conclusion: Masticatory function may act as a protective factor in those patients with cognition impairment and neurodegenerative diseases, suggesting some mechanisms among which is the increase of cerebral blood flow.
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    A Novel Three-Dimensional Analysis of Tongue Movement During Water and Saliva Deglutition: A Preliminary Study on Swallowing Patterns
    (2018)
    Giannina Álvarez
    ;
    Fernando José Dias
    ;
    María Florencia Lezcano
    ;
    Alain Arias-betancur
    ;
    Ramón Fuentes
    Deglutition is a complex oral function, and the study of the whole process requires a precise analysis of the elements involved, especially of the tongue biomechanics. We described a three-dimensional analysis of tongue movements during both saliva and water deglutition in participants with normal occlusion. Fourteen participants (25.36 ± 4.85 years) were evaluated, and the movements of anterior, middle, and posterior portions of the tongue were recorded using AG501 3Delectromagnetic articulograph. An average volume (AVS) for water deglutition was determined for each participant. Saliva deglutition was classified according to Bourdiol et al. 35.71% was type I, 14.29% type II, and 50% type III. The greatest displacement on the inferior–superior axis was in the posterior portion, followed by the middle and anterior portions. In the posterior–anterior axis, smallest movement was in the anterior portion. During water deglutition, on the inferior–superior axis, there were statistical differences for 1-AVS between the anterior/middle and anterior/posterior portions of the tongue. There were statistical differences for both -AVS and -AVS between the anterior/posterior portions of the tongue. On the posterior–anterior axis, there were no statistical differences among any volume–portion relations. On the medial–lateral axis, there was statistical difference for the -AVS between middle and posterior portions. The movement of the tongue portions was influenced by the volume and the element to be swallowed. The amplitude of the movement was directly proportional to the volume of water swallowed.
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    A New Tridimensional Insight into Geometric and Kinematic Characteristics of Masticatory Cycles in Participants with Normal Occlusion
    (2018)
    Ramón Fuentes
    ;
    Alain Arias
    ;
    María Florencia Lezcano
    ;
    Diego Saravia
    ;
    Gisaku Kuramochi
    <jats:p>The aim of this study was to analyze the general, geometric, and kinematic characteristics of the masticatory cycle’s movements in a tridimensional way, using a method developed by our study group to provide a new insight into the analysis of mandibular movements due to advancement in the potential of computational analysis. Ten individuals (20.1 ± 2.69 years), molar class I, without mandibular movement problems participated in this study. The movements of the masticatory cycles, frontal and sagittal mandibular border movements, were recorded using 3D electromagnetic articulography and processed with computational scripts developed by our research group. The number of chewing cycles, frequency (cycles/s), chewing cycle areas/mandibular border movements areas ratios, and the mouth opening and closing speeds on the 3D trajectory of the chewing cycle were compared. The cycles were divided and analyzed in thirds. The masticatory cycles showed high variation among the individuals (21.6 ± 9.4 cycles); the frequency (1.46 ± 0.21 cycles/s) revealed a moderate positive correlation (R = 0.52) with the number of cycles. The frontal area ratios between the cycle area and the mandibular border movement presented higher values in the first third (6.65%) of the masticatory cycles, and the ratios of sagittal areas were higher and more variable (first, 7.67%; second, 8.06%; and third, 10.04%) than the frontal view. The opening and closing mouth speeds were greater in the second third of the masticatory cycles (OS, 57.82 mm/s; CS, 58.34 mm/s) without a significant difference between the opening and closing movements when the same thirds were evaluated. Further studies are necessary to improve the understanding of the masticatory cycles regarding the standardization of parameters and their values.</jats:p>
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    Analysis of mandibular movements and chewing cycles in patients with Skeletal Class III: a preliminary study using 3D electromagnetic articulography
    (2018)
    Ramón Fuentes
    ;
    Diana Constanza Farfán Melo
    ;
    Fernando J. Dias
    ;
    Alain Arias-betancur
    ;
    María Florencia Lezcano
    Background. Study of mandibular movements (MM) was introduced into oral physiology to increase knowledge of the stomatognathic system and achieve better results in treatments. Electromagnetic Articulography (EMA), specifically the most recent equipment, AG501, plays an important role in these objectives, since it permits description of movements in 3 dimensions by recording the position of body parts at a high sampling frequency. Aim. The aim of the present study was to report an exploratory analysis of the geometrical characteristics (area, trajectory, ranges) and the velocity of border and functional MM in patients with Skeletal Class III by the use of EMA AG501. Material and methods. Two individuals with skeletal class III, patients at the Dental Teaching Clinic of the Dental Faculty of Universidad de La Frontera, Chile, were assessed and the results were processed with computer scripts developed specifically for this study. Results. The result produced from border MM was Posselt&amp;#39;s envelope in the frontal and sagittal planes, allowing analysis of the morphology and area. The result obtained from the mastication movements was an assessment of the area of each chewing cycle, which was compared with the area of the envelopes in the various planes. We also analysed the number, frequency and velocity of cycles, comparing them with available data.