Artículos de Investigación

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Chewing Index: A Pilot Trial to Measure Masticatory Effort
(2026)
Franco Marinelli
;
Camila Venegas-Ocampo
;
Josefa Alarcón-Apablaza
;
Rosemarie Schneider
;
Pablo Navarro
<jats:p>Background/Objectives: Population aging presents new challenges for achieving healthy aging. Edentulism is a condition that diminishes quality of life. Several studies have attempted to analyze the impact of edentulism on masticatory function either by evaluating the final stage of the food bolus or the masticatory process itself. The present study aims to develop a chewing index (Ci) based on chewing time, the number of cycles, and the muscular activity of the masseter and temporal muscles. Methods: Two groups (n = 10 each, 60–80 years old), one with functional dentition (21 or more teeth) (Group F) and one with complete denture wearers (Group D), were used. Participants were asked to chew a total of 36 food samples. The number of chewing cycles (N), chewing time (T), and bilateral activity of the masseter and anterior temporal muscles were recorded and quantified using the root mean square. This activity was normalized with respect to a 5 s maximum voluntary clenching (TMAV). A chewing index (Ci) was calculated using the equation Ci = N × V%¯ × T/TMAV, where V%¯ represents the average normalized activity of the four muscles. Results: Ci values ranged from 0 to 62 for Group F and 0 to 262 for Group D. For 15 out of the 36 food samples, Ci was higher in Group D than in Group F. Conclusions: The results of this study are consistent with previous research showing that complete denture wearers must chew for a longer time and perform a greater number of chewing cycles compared with subjects with functional dentition.</jats:p>
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Evaluation of Mandibular Border Movements and Mastication in Patients with Temporomandibular Disorders: A Pilot Study with 3D Electromagnetic Articulography and Surface Electromyography
(2025)
Camila Cerda
;
Franco Marinelli
;
Jarpa-Parra, Marcela
;
Pablo Navarro
;
Ramón Fuentes
Temporomandibular disorders (TMD) are characterized by pain and restricted functionality of the temporomandibular joint (TMJ). The objective of this study was to characterize the kinematic and electromyographic patterns of mandibular border movements and mastication in patients with different forms of TMD compared with healthy controls, through a simultaneous three-dimensional electromagnetic articulography (EMA-3D) and surface electromyography (sEMG) recording protocol. Sixteen participants were included and divided into three groups according to the TMD diagnosis (articular, muscular and mixed) and one healthy control group. Kinematic data were recorded using EMA-3D, and electromyographic activity of the masticatory muscles was assessed using sEMG. Variables analyzed included trajectories, areas, ranges, and electrical activity during mandibular border movements and mastication. Patients with TMD exhibited reduced movement trajectories but larger areas within the mandibular polygons, particularly in the frontal and sagittal planes. During mastication, the number of cycles was higher in the muscular group and lower in the healthy controls. Patients with TMD showed greater mean electromyographic activity, which could suggest compensatory muscle strain. The EMA-3D system provided an accurate threedimensional analysis, while sEMG captured detailed patterns of muscle activation and strain, that help better understand the neuromuscular alterations associated with TMD. Differentiation between TMD types (articular, muscular and mixed) for the study of its kinematic and electromyographic characteristics, is essential to improve diagnosis and treatment strategies. This study highlights the relevance of advanced tools such as EMA-3D and sEMG in the evaluation of TMD using a simultaneous recording protocol such as the one proposed in this study.
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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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Location and course of the mandibular canal in dentate patients: morphometric study using cone-beam computed tomography
(2019)
Alain Arias
;
C. Venegas
;
N. Soto
;
I. Montiel
;
C. Farfán
Background: The morphometric characteristics of the mandibular canal (MC) may vary according to the characteristics of the population studied. Correct location of the MC is fundamental for the indication and planning of different dental treatments, and it is therefore essential to have clinical parameters indicating its approximate location. The aim of this study was to describe the location and course of the MC by morphometric relations in the mandibular body, from the mental foramen to distal of the first molar, in dentate adult patients. Materials and methods: We analysed 55 cone-beam computed tomography (CBCT) of male and female patients, aged over 18 years and with fully dentate to the first molar. In each CBCT we selected five coronal sections (A-E) of the mandibular body at different levels using the teeth as references. We determined different morphometric measurements in each section to relate the MC with the corticals of the mandibular body (m1, m2, m3, m4), their orientation to lingual (F) and the thickness of the mandibular corticals (B1, B2 and B3). Results: The distance between the MC and the alveolar crests was greater in males than in females in all the sections. In general, in all the hemiarches, the MC courses away from the vestibular cortical of the mandible (and in some cases significantly towards the lingual cortical) from anterior to posterior in the mandibular body. In the left hemiarch of dentate females the MC describes a descent in the molar zone within the mandibular body. Any intervention in the mandible must be carried out with extreme caution to avoid damaging the vasculo-nervous bundle which passes through the MC. Conclusions: Cone-beam computed tomography is the best tool currently available for the planning and execution of surgical procedures, and is the only tool in clinical use which allows the precise course of the MC to be identified.
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Platelet‐rich fibrin and collagen membrane in the preservation of the alveolar bone: Feasibility of the elemental inorganic composition and scanning electron microscopy analysis
(2019)
Fernando José Dias
;
Alain Arias
;
Eduardo Borie
;
Ramón Fuentes
<jats:title>Abstract</jats:title><jats:p>The success of dental implants is related to the amount, quality, and composition of the alveolar bone. The placement of platelet‐rich fibrin (PRF) clot associated with a resorbable collagen membrane (RCM) in a postextraction alveolus is a technique used for ridge preservation. This case report study analyzed the ultrastructural characteristics of cross‐sectioned alveolar bone that received PRF and RCM using scanning electron microscopy and the inorganic composition using “energy dispersive X‐ray spectrometry,” in order to explore the feasibility of this method to clinical studies. Three alveolar bone samples from two male patients (37 and 58 years old), obtained in the procedure of placing the dental implant, were analyzed. Two bone samples previously received PRF and RCM (M37 and M58), the third sample represented a physiological bone formation without treatment (M37‐control). The bone sample M37 showed irregularly shaped islets of calcified material intermingled with connective tissue. The other samples, from the 58‐year‐old patient with PRF and RCM (M58); and the other untreated bone sample from the same 37‐year‐old patient (M37‐control) showed similar ultrastructural morphology with trabecular conformation without islets agglomerations. The inorganic composition analysis showed higher concentrations of calcium and phosphorus in both samples treated with PRF and RCM in comparison to the untreated bone sample. The Ca/P ratio was higher in the M37 sample compared to the others samples. The results showed morphology and inorganic composition differences among the treatments used, suggesting that this method is feasible to analyze parameters of the alveolar bone tissue.</jats:p>
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Comparison of Morphological Quantitative Characteristics of the Newly Formed Alveolar Bone After the Application of Demineralized Bone Matrix and Cortical Bone Allografts
(2019)
Fernando José Dias
;
Alain Arias
;
Eduardo Borie
;
Maria Florencia Lezcano
;
Manuel Arellano-Villalón
The allografts were used to obtain sufficient alveolar bone tissue for proper dental implant placement. The objective of the present study was to evaluate the morphological and quantitative characteristics (cellular and collagen densities) of the newly formed alveolar bone with the application of cortical bone (CB) and demineralized bone matrix (DBM) allografts. Six samples of alveolar bone tissue from 5 patients (50 ± 6.3 years) were obtained after 6 months of application of the allografts and immediately before the placement of the dental implants. The samples were fixed (buffered formaldehyde, pH7.2), decalcified (EDTA 10 %) and histologically processed (HE and Picro-Sirius) for histologic analysis. Morphological analysis revealed presence of osteocytes and trabeculae in neoformed bone tissue near the allografts and absence of inflammatory and allergic cells; the remnants of CB were located mainly in the periphery of the bone tissue and the remnants of DBM were more incorporated into the tissue. Osteogenitor cells were observed around the remaining material. The cell density was not modified in newly formed bone tissue with the application of both allografts as compared to mature bone tissue. The density of the type I and III collagens present in the osteoids interspersed with the remainder of the materials showed a tendency to increase in the samples treated with DBM. It was concluded that by the histological characteristics observed both grafts were biocompatible, however the bone treated with DBM presented better incorporation and a tendency of increase of the collagen content in the remnant region of the allografts.
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Assessment of Maxillary Premolar Region in Relation to Maxillary Sinus Floor and Buccal Bone Plate: A Cone Beam Computed Tomography Study
(2019)
Ramón Fuentes
;
Manuel Arellano Villalón
;
Soto-Faúndez, Natalia
;
Alain Arias
;
Montiel, Ignacio
The maxillary sinus floor location and the buccal bone plate are factors to be considered in the long-term success with implant treatments mainly in the premolar region. the aim of this study was to establish morphometric characteristics of the buccal cortical bone (BCB) thickness of maxillary premolars and its relation to maxillary sinus floor through CBCT. In this study 350 first and second maxillary premolars were analyzed from 110 CBCT images and the buccal cortical bone (BCB) was measured in a coronal view at the major axis level of each premolar. In addition, in 200 first and second maxillary premolars CBCT images were measured the distance from premolar apex to maxillary sinus floor (MSF) in both frontal and sagittal plane. The type of relationship between the apex and MSF was classified according to Ok et al. (2014). The second premolar was observed with higher values of BCB (p<0.001). In first premolar, higher values were observed in the male sex (p>0.05). In second premolar, only significantly higher values were observed in the male sex in MA-MB-MC (p>0.05). Regarding to MSF and its relation to premolar roots, it was observed that 10 % of the sample was classified as type I, 19 % as type II, 55.5 % as type III and 15.5 % as type IV. The BCB of the upper premolar region is thicker in the apical region and decreases toward the coronal region. Almost 50 % of apex of second premolars are closely and risky related MSF (Type I and II).
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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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