Physiological Model of the Masticatory System

Author(s):  
Shane Xie
2018 ◽  
Vol 10 (2) ◽  
Author(s):  
Gabriel Muñoz Quintana

La musculatura del sistema masticatorio y la articulación temporomandibular (ATM) están protegidos por reflejos nerviosos básicos y sistema neuromuscular a través de la coordinación de fuerzas musculares, todo lo que produce sobrecarga muscular repetitiva como los hábitos parafuncionales (HPF) pueden ocasionar trastornos temporomandibulares (TTM)1. Los HPF se caracterizan por movimientos anormales a la función mandibular normal sin objetivo funcional, al estar alterados constituyen una fuente productora de fuerzas traumáticas caracterizadas por dirección anormal, intensidad excesiva y repetición frecuente y duradera (Rolando Castillo Hernández, 2001)4. El objetivo del estudio fue identificar la asociación entre la presencia de hábitos parafuncionales de la cavidad bucal y los TTM en adolescentes de la ciudad de Puebla. Estudio observacional descriptivo. Se incluyeron 258 adolescentes, 132 (51.2%) mujeres y 126 (48.8%) hombres, con una edad promedio de 12.5±.73 y quienes fueron diagnosticados con los CDI/TTM y los HPF fueron auto-reportados por los pacientes. Se encontró una prevalencia de los TTM del 39.9% y una prevalencia de HPF del 86%. Los HPF más frecuentemente reportados fueron la succión labial y la onicofagia. Se encontró una asociación significativa (x2=7.31, p=0.007) entre los hábitos parafuncionales y los TTM en adolescentes. Palabras clave: Trastornos temporomandibulares, hábitos parafuncionales, adolescentes, articulación temporomandibular. Abstract The muscles of the masticatory system and temporomandibular joint (TMJ) are protected by basic nerve reflex and neuromuscular system through the coordination of muscle forces, all that repetitive muscle overload occurs as habit parafunctional (HPF) can cause temporomandibular disorder TMD)1. The characteristics of HPF are abnormal jaw movements without a functional objective. Being the jaw movements altered, they constitute a source of traumatic forces with an abnormal direction, excessive intensity and long-lasting and frequent duration. (Rolando Hernandez Castillo 2001)4. Objective: was to identify the association between the presences of parafunctional habits of the oral cavity and TMD in adolescents in the Puebla city in Mexico. Material and methods: Is a observational study, we included 258 adolescents 132 (51%) females and 126 (48.8%) were men, mean age 12.5±.73 and who were diagnosed with CDI/TTM and HPF were self- reported by patients. Results: The prevalence of TMD was 39.9% and a prevalence of 86% HPF. The most frequently reported HPF were lip sucking and nail biting. We found a significant association (x2= 7.31, p = 0,007) between HPF and TMD in adolescents. Key words: Parafunctional habits of oral cavity, temporomandibular disorders, temporomandibular joint. (Odontol Pediatr 2011;10(2): 90-94).


2015 ◽  
Vol 3 (5) ◽  
Author(s):  
Eva Jablonka ◽  
Ehud Lamm

<p class="p1"><span class="s1"><strong>Abstract </strong></span>| Lamarck has left many legacies for future generations of biologists<span class="s2"><strong>. </strong></span>His best known legacy was an explicit suggestion, developed in the <em>Philosophie zoologique </em>(PZ), that the effects of use and disuse (acquired characters) can be inherited and can drive species transformation.This suggestion was formulated as two laws, which we refer to as the law of biological plasticity and the law of phenotypic continuity<span class="s2"><strong>. </strong></span>We put these laws in their historical context and distinguish between Lamarck’s key insights and later neo-Lamarckian interpretations of his ideas<span class="s2"><strong>.</strong></span>We argue that Lamarck’s emphasis on the role played by the organization of living beings and his physiological model of reproduction are directly relevant to 21st-century concerns, and illustrate this by discussing intergenerational genomic continuity and cultural evolution.</p>


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nicole Pretini ◽  
Leonardo S. Vanzetti ◽  
Ignacio I. Terrile ◽  
Guillermo Donaire ◽  
Fernanda G. González

Abstract Background In breeding programs, the selection of cultivars with the highest yield potential consisted in the selection of the yield per se, which resulted in cultivars with higher grains per spike (GN) and occasionally increased grain weight (GW) (main numerical components of the yield). In this study, quantitative trait loci (QTL) for GW, GN and spike fertility traits related to GN determination were mapped using two doubled haploid (DH) populations (Baguette Premium 11 × BioINTA 2002 and Baguette 19 × BioINTA 2002). Results In total 305 QTL were identified for 14 traits, out of which 12 QTL were identified in more than three environments and explained more than 10% of the phenotypic variation in at least one environment. Eight hotspot regions were detected on chromosomes 1A, 2B, 3A, 5A, 5B, 7A and 7B in which at least two major and stable QTL sheared confidence intervals. QTL on two of these regions (R5A.1 and R5A.2) have previously been described, but the other six regions are novel. Conclusions Based on the pleiotropic analysis within a robust physiological model we conclude that two hotspot genomic regions (R5A.1 and R5A.2) together with the QGW.perg-6B are of high relevance to be used in marker assisted selection in order to improve the spike yield potential. All the QTL identified for the spike related traits are the first step to search for their candidate genes, which will allow their better manipulation in the future.


Author(s):  
Mirja Möhn ◽  
Julia Camilla Bulski ◽  
Norbert Krämer ◽  
Alexander Rahman ◽  
Nelly Schulz-Weidner

Amelogenesis imperfecta (AI) is defined as an interruption of enamel formation due to genetic inheritance. To prevent malfunction of the masticatory system and an unaesthetic appearance, various treatment options are described. While restoration with a compomer in the anterior region and stainless steel crowns in the posterior region is recommended for deciduous dentition, the challenges when treating such structural defects in mixed or permanent dentition are changing teeth and growing jaw, allowing only temporary restoration. The purpose of this case report is to demonstrate oral rehabilitation from mixed to permanent dentition. The dentition of a 7-year-old patient with AI type I and a 12-year-old patient with AI type II was restored under general anesthesia to improve their poor aesthetics and increase vertical dimension, which are related to problems with self-confidence and reduced oral health quality of life. These two cases show the complexity of dental care for structural anomalies of genetic origin and the challenges in rehabilitating the different phases of dentition.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 629
Author(s):  
Helena Moratin ◽  
Pascal Ickrath ◽  
Agmal Scherzad ◽  
Till Jasper Meyer ◽  
Sebastian Naczenski ◽  
...  

Zinc oxide nanoparticles (ZnO-NP) are commonly used for a variety of applications in everyday life. In addition, due to its versatility, nanotechnology supports promising approaches in the medical sector. NP can act as drug-carriers in the context of targeted chemo- or immunotherapy, and might also exhibit autonomous immune-modulatory characteristics. Knowledge of potential immunosuppressive or stimulating effects of NP is indispensable for the safety of consumers as well as patients. In this study, primary human peripheral blood lymphocytes of 9 donors were treated with different sub-cytotoxic concentrations of ZnO-NP for the duration of 1, 2, or 3 days. Flow cytometry was performed to investigate changes in the activation profile and the proportion of T cell subpopulations. ZnO-NP applied in this study did not induce any significant alterations in the examined markers, indicating their lack of impairment in terms of immune modulation. However, physicochemical characteristics exert a major influence on NP-associated bioactivity. To allow a precise simulation of the complex molecular processes of immune modulation, a physiological model including the different components of an immune response is needed.


2021 ◽  
Vol 11 (5) ◽  
pp. 2176
Author(s):  
Krzysztof Dowgierd ◽  
Rafal Pokrowiecki ◽  
Maciej Borowiec ◽  
Marcin Kozakiewicz ◽  
Dominika Smyczek ◽  
...  

Extended postoperative mandibular reconstructions due to orofacial disease involving the temporomandibular joint (TMJ) in immature patients remain a challenge as a result of ongoing growth, which is usually affected by the disease and treatment. Current reconstructive techniques based fully on alloplastic total joint replacement fail to meet fully the anatomical and functional requirements for the masticatory system and speech development. Fourteen children aged 12.6 ± 2.6 with tumors or congenital deformities affecting the mandible and TMJ were included in the study. Radical surgical treatment according to our own protocol was performed through microvascular anastomotic flap reconstruction of the soft tissues and bones, together with total TMJ custom replacements. Follow-up lasted 2–6 years. During the follow-up, increases in the mandible body (13% growth) and ramus (12% growth) were observed, both of which were related (p < 0.001). This is the first report concerning the immediate reconstruction of the mandible with ramus and total TMJ in children and adolescents that combines a free vascularized graft and total individual prosthesis of the TMJ. The presented technique enabled optimal function of the TMJ, growth of the mandible, and further rehabilitation of the patients. The technique was demonstrated to be safe, reliable, and provide good functional and cosmetic outcomes.


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