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1.
Braz. dent. sci ; 24(1): 1-9, 2021. tab, ilus
Artículo en Inglés | LILACS, BBO - Odontología | ID: biblio-1145518

RESUMEN

Objective: To determine the force decay and discoloration in Generation I and Generation II elastomeric chain on artificial saliva immersion. Material and methods: Generation I and Generation II elastomeric chains stretched on an acrylic board and immersed in artificial saliva for 1, 7, 14, 21, and 28 days according to the group of days. On each specified day, the force of each sample measured by an orthodontic force gauge and the magnitude of the force obtained is entered to the formula to find out the force decay in percentage, whereas discoloration of each sample analyzed by the color reader with CIE Lab analysis. Results: The force decay between Generation I and Generation II elastomeric chains showed a statistically significant difference in every group of days, in which Generation II is more effective in maintaining stretch force. Similar to force decay, the discoloration in Generation I elastomeric chains on the 14th day showed significant value and Generation II elastomeric chains were more stable in maintaining color compared to Generation I. Conclusions: over the entire research period time, Generation II elastomeric chains are more stable in maintaining stretch forces and color compared to Generation I elastomeric chains. (AU)


Objetivo: Determinar a queda de força e descoloração nos elásticos ortodônticos tipo corrente de Geração I e Geração II na imersão em saliva artificial. Material e métodos: Elásticos Geração I e Geração II foram esticados em placas de acrílico e imersas em saliva artificial por 1, 7, 14, 21 e 28 dias, de acordo com o grupo de dias. Em cada dia especificado, a força de cada amostra medida por um medidor de força ortodôntica e a magnitude da força obtida são inseridos na fórmula para descobrir sua queda em porcentagem, enquanto a descoloração de cada amostra foi analisada pelo leitor de cores "CIE Lab". Resultados: A queda da força entre os elásticos Geração I e Geração II apresentou diferença estatisticamente significativa em todos os grupos de dias, sendo que a de Geração II foi mais efetiva na manutenção da força de alongamento. Semelhante à queda de força, a descoloração nos elásticos da Geração I mostrou um valor significativo no 14º dia, e elásticos da Geração II foram mais estáveis na manutenção da cor em comparação com a Geração I. Conclusões: durante todo o período de pesquisa, os elásticos tipo corrente da Geração II foram mais estáveis na manutenção das forças de alongamento e da cor em comparação com os elásticos da Geração I (AU)


Asunto(s)
Saliva Artificial , Técnicas de Movimiento Dental , Fuerza de la Mordida
2.
J Clin Pediatr Dent ; 44(6): 423-428, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-33378468

RESUMEN

OBJECTIVE: To determine the maximum occlusal bite force (MOBF) of the complete spectrum of dental caries in first permanent molars (FPMs) in children aged 7-9 years. STUDY DESIGN: A cross-sectional study was conducted on 123 children. The evaluation of the caries spectrum of FPMs was carried out using the Caries Assessment Spectrum and Treatment index (CAST). The MOBF was measured in the FPM region using the portable occlusal force gauze. Independent sample t-test and one-way analysis of variance test were performed to compare MOBF with CAST scores of FPMs. Based on the CAST scores, FPMs were categorized into three groups, group 1: healthy (score 0, 1, 2), group 2: premorbid (score 3), group 3: morbid (score 4, 5). RESULTS: A significantly lower MOBF was observed (167.56 N ± 49.77) in the morbid stage (group 3) than in the premorbid stage (group 2: 291.57 N ± 56.64), and healthy (group 1; 320.93 N ± 54.23). Intergroup comparison also revealed that FPMs in the healthy stage was associated with a higher bite force compared to those in the premorbid and morbid stages (p<0.001). CONCLUSIONS: The mean MOBF decreased with the progression of the caries spectrum of FPMs in early permanent dentition.


Asunto(s)
Fuerza de la Mordida , Caries Dental , Niño , Estudios Transversales , Dentición Permanente , Humanos , Diente Molar
3.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 55(10): 743-749, 2020 Oct 09.
Artículo en Chino | MEDLINE | ID: mdl-33045785

RESUMEN

Objective: To quantitatively evaluate the change of the long axis angle and the relative displacement of the crown feature points of the posterior teeth under normal bite force utilizing an intraoral scanner, and to provide clinical reference. Methods: From May to December 2019, fifteen graduate volunteers (5 males and 10 females, aged from 22 to 30, with an average age of 25.7 years) from Peking University School and Hospital of Stomatology were recruited to participate in the study. The surface data (U1, L1) of the maxillary and mandibular posterior teeth were scanned by an intraoral scanner i500, and saved as original data. The volunteers were guided to bite in the intercuspal position with normal bite force. The buccal bite data of the posterior teeth were scanned as the basis for registration. The digital casts were imported into Geomagic studio 2013 software and the boundary lines along the gingival margin and mesial and distal contact area of posterior teeth of data (U1, L1) were determined. Long axis of the crown, crown centroid and mesial functional cusp vertex were establishd. The data (U1, L1) were segmented into single tooth. Single tooth was aligned to buccal bite data separately using best-fit alignment command based on the buccal common area of the crown and new casts data (U2, L2) were obtained as the data under bite force. The long axis angle and centroid distance between adjacent teeth (second premolar and first molar, second molar and first molar) were measured and the deviation between data obtained at mouth-open state and that at biting state was calculated. Negative value meant centroid distance became shorter under bite force. The first molar was set as the common area and registrate the U1, L1 to U2, L2. The angle of long axes, and displacement of centroid and of functional cusp vertex between second premolar of two casts were calculated, as well as between second molar of two casts. Wilcoxon signed rank test was used to analyze the differences of teeth displacement between second premolar and second molar, and between maxillary and mandibular jaws with SPSS 26.0 statistical software. Results: The result of second premolar and second molar in the same jaw had no statistical difference (P>0.05). The centroid distance deviation of mandibular second premolar-first molar [-0.022(0.046) mm] was larger than that of maxilla [-0.006 (0.040) mm] (P<0.05). The long axis angle of second premolar itself [0.913°(0.647°)] and centroid distance of second molar itself [0.102 (0.106) mm] on the mandibular jaw were different from that on the maxillary jaw, which were 0.590°(0.550°) and 0.074(0.060) mm respectively (P<0.05). Conclusions: Under bite force, displacement of the second premolar and second molar was present, including the displacement of centroids and deflection of long axes. The mandibular posterior teeth have larger displacement than the maxillary teeth.


Asunto(s)
Fuerza de la Mordida , Diente Molar , Adulto , Diente Premolar , Oclusión Dental , Femenino , Humanos , Masculino , Maxilar , Diente Molar/diagnóstico por imagen
4.
Braz Dent J ; 31(4): 399-403, 2020 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-32901716

RESUMEN

This cross-sectional observational study with 24 patients evaluated differences in bite force (BF) and masticatory performance (MP) between conventional complete denture (CCD) and implant mandibular overdenture (IMO) users and the correlation between these variables. The BF test was performed bilaterally with an occlusal force device. During the MP test, patients were asked to chew Optocal particles for 40 cycles. The Shapiro Wilk test was employed to verify the normality of the data, the student t test to identify differences between groups, and Pearson's correlation to investigate interrelationships between variables. A multiple linear regression was subsequently performed via the stepwise method. P values ≤0.05 were considered statistically significant. Unlike IMO users, CCD users presented a significant difference (25.6%) in BF between the dominant and non-dominant chewing side (p=0.04). IMO users presented significantly higher BF (p=0.01) without presenting a dominant side (p=0.38), and also performed significantly better for the following MP parameters: MPX50 values decreased by 27.25% in IMO users (p=0.01), MPB decreased by 48.38% (p=0.01), and ME 5.6 decreased by 53.25% (p=0.02), while ME2.8 increased by 151.57% (p=0.01). The BF and MPX50 in the IMO wearers group were negatively correlated (-0.57; p=0.05); this correlation coefficient was the only parameter included in the multivariate regression model. IMO users have higher BF and better masticatory performance than CCD users, especially in terms of chewed particles size reduction. MP is correlated with a higher BF in IMO users through better particle trituration.


Asunto(s)
Fuerza de la Mordida , Prótesis de Recubrimiento , Estudios Transversales , Dentadura Completa , Humanos , Mandíbula
5.
Proc Biol Sci ; 287(1935): 20201578, 2020 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-32962547

RESUMEN

The southern alligator lizard (Elgaria multicarinata) exhibits a courtship behaviour during which the male firmly grips the female's head in his jaws for many hours at a time. This extreme behaviour counters the conventional wisdom that reptilian muscle is incapable of powering high-endurance behaviours. We conducted in situ experiments in which the jaw-adductor muscles of lizards were stimulated directly while bite force was measured simultaneously. Fatigue tests were performed by stimulating the muscles with a series of tetanic trains. Our results show that a substantial sustained force gradually develops during the fatigue test. This sustained force persists after peak tetanic forces have declined to a fraction of their initial magnitude. The observed sustained force during in situ fatigue tests is consistent with the courtship behaviour of these lizards and probably reflects physiological specialization. The results of molecular analysis reveal that the jaw muscles contain masticatory and tonic myosin fibres. We propose that the presence of tonic fibres may explain the unusual sustained force properties during mate-holding behaviour. The characterization of muscle properties that facilitate extreme performance during specialized behaviours may reveal general mechanisms of muscle function, especially when done in light of convergently evolved systems exhibiting similar performance characteristics.


Asunto(s)
Maxilares/anatomía & histología , Lagartos/fisiología , Músculos Masticadores/anatomía & histología , Conducta Sexual Animal , Animales , Fuerza de la Mordida , Cortejo , Femenino , Masculino , Contracción Muscular , Músculo Esquelético
6.
Proc Biol Sci ; 287(1935): 20201818, 2020 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-32993469

RESUMEN

The acquisition of elongated, sabre-like canines in multiple vertebrate clades during the last 265 Myr represents a remarkable example for convergent evolution. Due to striking superficial similarities in the cranial skeleton, the same or similar skull and jaw functions have been inferred for sabre-toothed species and interpreted as an adaptation to subdue large-bodied prey. However, although some sabre-tooth lineages have been classified into different ecomorphs (dirk-tooths and scimitar-tooths) the functional diversity within and between groups and the evolutionary paths leading to these specializations are unknown. Here, we use a suite of biomechanical simulations to analyse key functional parameters (mandibular gape angle, bending strength, bite force) to compare the functional performance of different groups and to quantify evolutionary rates across sabre-tooth vertebrates. Our results demonstrate a remarkably high functional diversity between sabre-tooth lineages and that different cranial function and prey killing strategies evolved within clades. Moreover, different biomechanical adaptations in coexisting sabre-tooth species further suggest that this functional diversity was at least partially driven by niche partitioning.


Asunto(s)
Evolución Biológica , Carnívoros , Diente/anatomía & histología , Animales , Fenómenos Biomecánicos , Fuerza de la Mordida , Fósiles , Mandíbula , Cráneo/anatomía & histología
7.
Geriatr Gerontol Int ; 20(10): 917-926, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32830417

RESUMEN

AIM: This large epidemiological survey of older people examined oral hypofunction and the relationship between oral hypofunction and frailty. METHODS: Participants were community-dwelling adults aged 65-85 years in Japan. The oral function evaluation included seven items (oral hygiene, oral dryness, occlusal force, tongue-lip motor function, tongue pressure, masticatory function and swallowing function), and oral hypofunction was defined as having abnormalities in at least three of these items. The frailty status was classified into three categories (robust, pre-frail and frail) according to the total Kihon Checklist score. We analyzed 978 subjects with complete data. The relationship between oral function and frailty status was analyzed using multivariate multinomial logistic regression analyses. RESULTS: Approximately 60% of the older adults had oral hypofunction. The multivariate odds ratios (ORs) for a pre-frail or frail status were significantly higher for older people with reduced occlusal force, reduced tongue-lip motor function and deteriorated swallowing function than in those without deterioration of those items. Of the oral function items, swallowing function was most strongly associated with the frailty status, and the ORs (95% confidence interval [CI]) for deteriorated swallowing function in pre-frail and frail patients were 6.4 (3.9-10.8) and 10.2 (5.4-19.1), respectively. Those with oral hypofunction had significantly higher adjusted ORs for pre-frail (OR 1.4, 95% CI 1.1-2.0) and frail (OR 2.1, 95% CI 1.2-3.5) statuses. CONCLUSION: Many community-dwelling older people have reduced oral function or oral hypofunction, which is significantly associated with frailty in older people. Geriatr Gerontol Int 2020; 20: 917-926.


Asunto(s)
Anciano Frágil/estadística & datos numéricos , Salud Bucal/estadística & datos numéricos , Higiene Bucal/estadística & datos numéricos , Anciano , Anciano de 80 o más Años , Fuerza de la Mordida , Lista de Verificación , Estudios Transversales , Trastornos de Deglución/epidemiología , Femenino , Fragilidad , Evaluación Geriátrica , Humanos , Vida Independiente , Japón , Masculino , Masticación , Oportunidad Relativa , Encuestas y Cuestionarios , Xerostomía/epidemiología
8.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 37(4): 614-621, 2020 Aug 25.
Artículo en Chino | MEDLINE | ID: mdl-32840078

RESUMEN

As a representative part of the oral system and masticatory robot system, the modeling method of the dental model is an important factor influencing the accuracy of the multi-body dynamic model. Taking the right first molars of the masticatory robot as the research object, an equivalent model, point-contact higher kinematic pair composed of v-shaped surface and sphere surface, was proposed. Firstly, the finite element method was used to analyze the occlusal dynamics of the original model in three static contact cases (intrusive contact, centric occlusion, and extrusive contact) and one dynamic chewing case, and the expected bite force was obtained. Secondly, the Hertz contact model was adopted to establish the analytical expression of the bite force of the equivalent model in three static contact cases. The normal vectors and contact stiffness in the expression were designed according to the expected bite force. Finally, the bite force performance of the equivalent model in three static contact cases and one dynamic chewing case was evaluated. The results showed that the equivalent model could achieve the equivalent bite force of 8 expected items in the static contact cases. Meanwhile, the bite force in the early and late stages of the dynamic chewing case coincides well with the original model. In the middle stage, a certain degree of impact is introduced, but it can be weakened by subsequent trajectory planning. The equivalent modeling scheme of the dental model proposed in this paper further improves the accuracy of the dynamic model of the multi-body system. It provides a new idea for the dynamic modeling of other complex human contacts.


Asunto(s)
Diente Molar , Fenómenos Biomecánicos , Fuerza de la Mordida , Humanos , Masticación
9.
J Endod ; 46(12): 1849-1855, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32721484

RESUMEN

INTRODUCTION: The aim of this investigation was to determine the coronal strain variations in mandibular molars under an in vivo bite load after root canal treatment procedures. METHODS: The coronal strain in carious mandibular first molars with symptomatic irreversible pulpitis (experimental group) was compared with that of intact contralateral teeth (control group) in patients 20-40 years old. Experiments were conducted in 2 stages. In stage 1, the maximum bite force on the first molar region was determined on the experimental and control teeth using a customized load cell. In stage 2, strain gauges were bonded to the buccal aspect of teeth, and the strain was recorded after the application of a bite load on the intact (control) teeth; and the experimental teeth before and after endodontic access cavity preparation, cleaning/shaping procedures, root filling, and composite core restoration. RESULTS: The mean maximum bite force on the experimental teeth (91 ± 48 N) and the contralateral control teeth (91 ± 49 N) was not significantly different (P = .989). The preoperative strain (microstrain) in the experimental teeth was significantly higher (125 ± 36, P = .001) than in the contralateral intact teeth (46 ± 17). Access cavity preparation significantly increased the strain (327 ± 98, P = .019) on the experimental teeth compared with the preoperative strain. Cleaning/shaping (355 ± 113) and root filling (346 ± 89) did not significantly increase (P = 1.00) the strain compared with the strain determined after endodontic cavity preparation. Composite core restoration in the experimental teeth (106 ± 41) resulted in a significant reduction in the strain compared with the values recorded after an endodontic access cavity (P = .002) and was similar to the preoperative strain values (P = 1.00) but was significantly higher than the strain values in contralateral intact teeth (P = .001). CONCLUSIONS: The coronal strain on the buccal surface of mandibular first molars significantly increased with access cavity preparation, which did not increase further after cleaning/shaping or root filling. A significant reduction in the strain induced by root canal treatment steps was evident after composite core restoration.


Asunto(s)
Cavidad Pulpar , Diente Molar , Adulto , Fuerza de la Mordida , Preparación de la Cavidad Dental , Humanos , Diente Molar/cirugía , Tratamiento del Conducto Radicular , Adulto Joven
10.
Artículo en Inglés | MEDLINE | ID: mdl-32646041

RESUMEN

This study is aimed at investigating the effects of synchronized neuromuscular electrical stimulation (NMES) and chewing exercises on bite force and the masseter muscle thickness in community-dwelling older adults. Material and methods: Forty older adults were enrolled in South Korea and randomly assigned to either an experimental or control group. The experimental group performed chewing exercises using the No-Sick Exerciser equipment synchronized with NMES applied to the bilateral masseter muscles, while the control group performed only chewing exercises. Both groups received interventions for 20 min/day, 5 days/week, for 6 weeks. Bite force was measured using the OCCLUZER device, and masseter muscle thickness was measured using a portable ultrasound. Results: Both groups showed a significant increase in bite force and masseter muscle thickness compared to baseline measurements (p < 0.05). The experimental group showed a significantly higher increase in bite force and masseter muscle thickness than the control group after combined intervention (p < 0.05). Conclusion: This study demonstrates that NMES synchronized with chewing exercises is more efficient in increasing bite force and masseter muscle thickness than chewing exercises alone in community-dwelling older adults.


Asunto(s)
Fuerza de la Mordida , Estimulación Eléctrica , Músculo Masetero , Masticación/fisiología , Músculos Masticadores/fisiopatología , Anciano , Electromiografía , Femenino , Humanos , Vida Independiente , Masculino , Músculo Masetero/anatomía & histología , Músculo Masetero/diagnóstico por imagen , República de Corea , Ultrasonografía
11.
J Oral Rehabil ; 47(9): 1161-1170, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32621336

RESUMEN

BACKGROUND: There is a wide variation of chewing behaviours even in healthy humans. The present study was aimed to clarify how the rheological properties of the bolus during chewing are different among individuals. We also investigated whether the swallowing threshold was consistent among the individuals and whether the difference in the bolus properties at the swallowing affected swallowing movement. METHODS: Twenty-nine healthy volunteers were asked to ingest 8 g of steamed rice. Based on the chewing duration defined by the time until first swallow, participants were asked to chew the food and then either spit it out or swallow it at 50%, 100% and 150% of chewing duration. In seven volunteers, the maximum bite force was measured. RESULTS: The hardness of the bolus gradually decreased throughout recording. Although the chewing duration varied widely, there was a significant negative correlation between time and hardness, regardless of the difference in individual chewing duration. The cohesiveness of the bolus was unchanged at the 100% time point, followed by a slight but significant increase. There was no significant correlation between the chewing duration and adhesiveness of the bolus. Swallowing-related bursts of Supra and Infra EMGs were not related to the chewing duration or bolus properties, and chewing duration did not affect swallowing function. CONCLUSION: The current results suggest that the bolus properties such as the hardness and cohesiveness during chewing are just dependent on the chewing duration and the difference in the bolus properties does not affect the swallowing initiation and movement.


Asunto(s)
Deglución , Masticación , Fuerza de la Mordida , Ingestión de Alimentos , Alimentos , Humanos
12.
Prague Med Rep ; 121(2): 87-95, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32553092

RESUMEN

Osteoarthrosis is a disorder of synovial joints, resulting from destruction of the cartilage and subchondral bone. The present study is aimed to investigate the molar bite force, thickness and efficiency of the masseter and temporalis muscles of subjects with osteoarthrosis. A total of forty-eight subjects participated in the study. They were distributed into two groups: with osteoarthrosis (n=24) and asymptomatic controls (n=24). Subjects were analyzed on the basis of maximal molar bite force (right and left side), thickness (mandibular rest and dental clenching in maximal voluntary contraction) and electromyographic activity of masticatory cycles through the linear envelope integral in habitual (raisins and peanuts) and non-habitual (Parafilm M) chewing of the masseter and temporalis muscles. All the data were analyzed statistically using t-test with a significance level of p≤0.05. There was no difference between groups in maximal molar bite force, muscle thickness and non-habitual chewing. Differences were found on the raisins (p=0.02) and peanuts (p=0.05) chewing for right temporal muscle, with reduced masticatory muscle efficiency in osteoarthrosis subjects. This study showed that osteoarthrosis induces negative changes in habitual chewing, highlighting the efficiency of the right temporalis muscles. The greater temporal muscle activity in subjects with osteoarthrosis may compromise chewing and consequently the nutritional status of adult subjects.


Asunto(s)
Fuerza de la Mordida , Osteoartritis , Adulto , Electromiografía , Humanos , Diente Molar , Osteoartritis/fisiopatología , Músculo Temporal
13.
J Oral Rehabil ; 47(9): 1103-1109, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32589302

RESUMEN

Chewing exercises have been applied in clinical settings to improve the occlusal force and function of the masseter muscle in elderly individuals. However, the clinical relevance and effects of chewing exercises are unclear. This study aimed to investigate the effects of bilateral chewing exercises on the occlusal force and masseter muscle thickness in community-dwelling Koreans aged 65 years. Forty community-dwelling healthy elderly individuals were enrolled in this study. They were assigned to the experimental or the control group. The experimental group performed chewing exercises using medical equipment developed to facilitate such exercises. The chewing exercises were divided into isometric and isotonic types and were performed for 20 min/d, 5 days/wk, for 6 weeks. The control group did not perform any chewing exercises. The outcome measures were occlusal force and masseter muscle thickness, which were evaluated using an occlusometer and ultrasound device, respectively. A paired t test and an independent t test were used to evaluate the training effects. Within-group comparisons showed that occlusal force and masseter muscle thickness improved significantly in the experimental group (P < .001 for both), while the control group showed no significant improvements (P = .098 and .130). Between-group comparisons showed that the experimental group had a greater increase in occlusal force and masseter muscle thickness (P < .05 for both) compared to the control group. These results suggest that chewing exercises are effective in improving occlusal force and masseter muscle thickness in healthy elderly individuals.


Asunto(s)
Fuerza de la Mordida , Terapia por Ejercicio , Músculo Masetero , Masticación , Anciano , Electromiografía , Humanos , Vida Independiente , República de Corea
14.
Rev. Ateneo Argent. Odontol ; 62(1): 13-23, jun. 2020. graf
Artículo en Español | LILACS | ID: biblio-1148125

RESUMEN

El presente es un trabajo de investigación bibliográfica que busca establecer la posibilidad de utilizar las cefalometrías como elementos de diagnóstico pronóstico y elaboración de prótesis. Centra su objeto de estudio en encontrar y clasificar los factores morfológicos y funcionales que varían con los biotipos craneofaciales y que son de interés en la prostodoncia. La metodología empleada fue la revisión de la literatura histórica hasta la actualidad en la que se relacionan temas de prostodoncia a los biotipos craneofaciales. Si bien solo dos autores relacionaron la prostodoncia con los biotipos cráneo faciales, sí se encontraron varios temas de interés asociados directamente a la prostodoncia. Se clasificaron en temas de oclusión: Curva de Spee, plano de oclusión, movimientos mandibulares, dimensión vertical oclusiva y de especio libre interoclusal. Tema de maloclusiones. Tema de fuerza muscular. Tema variaciones morfológicas de procesos alveolares, corticales ósea y de la forma dentaría. Encontrándose para cada uno de ellos alguna correlación positiva con los distintos tipos faciales. De este estudio, se concluye que es necesario sistematizar el estudio de los conocimientos que puede aportar la cefalometría como una importante herramienta de diagnóstico al prostodoncista a partir de haberse encontrado variaciones muy importantes en los aspectos mencionados que hacen al interés de la rehabilitación prostodóncica (AU)


This Work is a bibliographic research that seeks to establish the use of cephalometries as elements of diagnosis prognostic and prosthesis elaboration. Its focus is to find and classify morphological and functional factors that vary with facial types which are of interest in prosthodontics. This was a review of the historical literature to date, in which prosthodontics are related to facial types. Although only two authors related prosthodontics to facial ypes, they did find several topics of interest directly associated with prosthodontics. They were classified into occlusion themes: Spee curve, occlusion plane, mandibular movements, occlusive vertical dimension and interocclusal free space. Malocclusion issue. Muscle strength theme. Morphological variations of alveolar processes, cortical bone and dental morphology. They found some positive correlation with the different facial types for each of them. From this study, it is concluded that it is necessary to systematize the study of cephalometries because they can provide to be an important diagnostic tool to the prosthodontist because there were found very important variations in the mentioned aspects that are of interest in prosthodontic rehabilitation (AU)


Asunto(s)
Humanos , Fuerza de la Mordida , Biotipología , Prótesis Dental , Oclusión Dental , Maloclusión , Dimensión Vertical , Implantes Dentales , Cefalometría , Rehabilitación Bucal
15.
J Craniofac Surg ; 31(5): e451-e459, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32371699

RESUMEN

The aim of the study is to assess the occlusion in mandibular condyle fractures using T-Scan and analyze the data obtained. Twenty patients underwent non-surgical management for condylar fractures were treated with Erich arch bar and guiding elastics, and periodically subjected to T-Scan III evaluations. The data obtained was analyzed with the clinical evaluation conducted. There were 18 males and 2 females. Mean age of the patients was 25.4 ±â€Š7.4 years. There were statistically no significant changes in Centre of Force values, in Bite Force at First Contact (P < 0.05) during the study period. There were significant differences in Maximum Bite Force between preoperative and postoperative values, preoperative and sixth-month values, postoperative and first-month values, first-month and sixth-month values. There were significant (P < 0.05) differences in Bite Force at Maximum Intercuspation between preoperative and third month, preoperative and sixth-month values, postoperative and sixth-month values, first-month and consequent follow-ups. Subjective evaluation of occlusion revealed significant differences (P < 0.05) between preoperative and 1-month, preoperative and postoperative, postoperative and 1-month values. All patients improved by the end of 6 months with regards to their mouth opening. The center of force does not alter significantly in post trauma period. Mouth opening improves significantly at the end of 6-month period post-operative. Improvement in maximum bite force and maximum intercuspation take place simultaneously. Mouth opening improved significantly. Subjective evaluation of occlusion does not change significantly after the third month evaluation. Longer follow-ups would help us in understanding when or if the bite forces equilibrate after a condylar trauma.


Asunto(s)
Cóndilo Mandibular/diagnóstico por imagen , Fracturas Mandibulares/diagnóstico por imagen , Adolescente , Adulto , Fuerza de la Mordida , Oclusión Dental , Femenino , Humanos , Masculino , Cóndilo Mandibular/cirugía , Fracturas Mandibulares/cirugía , Periodo Posoperatorio , Cintigrafía , Adulto Joven
16.
Artículo en Inglés | MEDLINE | ID: mdl-32466588

RESUMEN

AIM: This study investigated the effect of neuromuscular electrical stimulation (NMES) on masseter muscle thickness and maximal bite force among healthy community-dwelling elderly persons older than 65 years. MATERIALS AND METHODS: A total of 40 participants were randomly assigned to the experimental and placebo groups. In the experimental group, NMES was applied to both masseter muscles, and electrical signals were gradually increased until the participants felt a grabbing sensation (range 6.0-7.5 mA) in the masseter muscle. The placebo group, in contrast, underwent NMES in the same manner and procedure as the experimental group with less electrical intensity (0.5 mA). All interventions were administered five times a week for six weeks, 20 min per day. The outcomes were masseter muscle thickness assessed using ultrasound and maximal bite force using a bite force meter. The level of significance was set as p < 0.05. RESULTS: The experimental group showed a significant increase in both masseter muscle thickness and maximal bite force as compared with the placebo group (p = 0.002 and 0.019, respectively). Moreover, the degree of change in the masseter muscle thickness and maximal bite force significantly increased in the experimental and placebo groups (p < 0.001, both). CONCLUSIONS: This study demonstrated that NMES could be an effective modality for increasing masseter muscle thickness and maximal bite force in healthy older adults.


Asunto(s)
Fuerza de la Mordida , Vida Independiente , Músculo Masetero , Anciano , Método Doble Ciego , Estimulación Eléctrica , Electromiografía , Femenino , Humanos , Masculino , Músculo Masetero/fisiología
17.
J Orofac Orthop ; 81(5): 371-381, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32472340

RESUMEN

AIM: The aim of this study was to evaluate the occlusal force distribution (OFD), individual tooth force (ITF), and occlusal surface area (OSA) of Essix and Hawley retainers, using T­Scan III (Tekscan Inc., South Boston, MA, USA) analysis. MATERIALS AND METHODS: A total of 35 subjects were randomly assigned to one of the retention groups following fixed orthodontic treatment. While 18 of these subjects were provided with Essix retainers, 17 were given Hawley retainers. Computerized occlusal analysis of the patients' dentitions was performed using T­Scan III. The evaluations were made after debonding (T0) and at month 3 (T1), month 6 (T2) and 1 year (T3) after the retention phase. RESULTS: The changes in OFD were significant only in the Hawley group for the left/right half jaws and the right posterior quadrants when comparing the T2-T3 time interval. Also, the differences between the groups were significant only for the left half jaw for the T0-T2 time interval and for the right half jaw when comparing the T0-T2 and the T2-T3 time intervals. The changes in ITF were insignificant within groups, but significant between the groups for tooth 11 and 22. Although there was an increase observed in OSA for both groups, the difference between the groups was insignificant. However, the OSA increase in the Essix group for the left/right anterior quadrants was significant only for the T0-T2 and the T0-T3 time intervals, while in both groups, for the posterior left quadrant, the OSA was insignificant only for the T0-T1 time interval. CONCLUSIONS: Although OSA increased when using both retention appliances, OFD did not change.


Asunto(s)
Diseño de Aparato Ortodóncico , Retenedores Ortodóncicos , Fuerza de la Mordida , Diente Canino , Humanos
18.
J Oral Rehabil ; 47(8): 989-997, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32428306

RESUMEN

In 2016, the Japanese Society of Gerodontology (JSG) proposed the concept of "oral hypofunction (OHF)," and recommended two initial criteria for reduced occlusal force (ROF): <200 N of maximum occlusal force (MOF) and < 20 remaining teeth. However, the JSG stated that these criteria need to be reviewed by accumulating further evidence. To examine the validity and equivalence of the two criteria for ROF in the diagnostic criteria for OHF by using the incidence of functional disability as the outcome. This study enrolled 815 community-dwelling Japanese individuals ≥ 70 years. They underwent examinations for physical, mental and social functions; MOF; and number of teeth at baseline. The incidence of functional disability (a condition that requires at least partial assistance with daily activities) based on the first certification of long-term care insurance was followed up. The Cox proportional hazard model revealed that MOF < 200 N (hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.04-1.72) and < 20 teeth (HR, 1.40; 95% CI, 1.07-1.84) were significantly associated with increased risk of functional disability. Receiver operating characteristic curve analyses revealed that the optimal cut-off values of MOF and number of teeth that best predicted incident functional disability were 264.6 N and 19 teeth, respectively. Twelve teeth were the optimal threshold that best predicted < 200 N of MOF. The two criteria for ROF in the diagnostic criteria for OHF had some degree of validity. However, further studies are needed to develop appropriate and reliable criteria for a decision of ROF.


Asunto(s)
Fuerza de la Mordida , Vida Independiente , Anciano , Humanos , Incidencia , Japón , Estudios Prospectivos
19.
J Prosthodont ; 29(6): 472-478, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32394526

RESUMEN

PURPOSE: Oral function in Down Syndrome (DS) patients has been of interest to clinicians and researchers. This study aimed to evaluate the parameters of occlusal force and pattern of children with Down syndrome (DS) during mixed dentition when compared to age and gender-matched controls. MATERIALS AND METHODS: Thirty DS and 30 healthy children, aged 7 to 12 years, participated in the evaluation of the parameters of the occlusal pattern and occlusal force distribution analysis. Both groups underwent clinical examination, occlusal force and pattern measurements using a computerized occlusal analysis system (T-Scan 8 occlusal analysis, Tekscan, Inc., S. Boston, MA). Occlusion time, percentage of force distribution, force outliers, center of force target area, center of force trajectory and evaluation of closure arc were compared between the two groups using the Pearson's Chi Square test. RESULTS: Children with DS had more occlusal and vertical malocclusion compared to the control group (p < 0.001). The occlusion time for DS group (0.75 ± 0.7s) was significantly longer than the control group (0.015 ± 0.05s) (p < 0.001). The closure arc for DS group was mostly irregular (53%), while the control group showed ideal closure arc. In control group, the age had a significant influence on the occlusion time, while height, weight, and BMI had a significant influence on the mouth opening. None of these variables had such effect on children with DS. CONCLUSIONS: The results of this study showed high prevalence of orofacial dysfunction among DS population. The occlusal analysis showed that children with DS had longer occlusion time and a lack of ideal occlusion pattern compared to age matched controls.


Asunto(s)
Síndrome de Down , Maloclusión , Fuerza de la Mordida , Niño , Oclusión Dental , Dentición Mixta , Humanos
20.
J Appl Oral Sci ; 28: e20190409, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32267378

RESUMEN

BACKGROUND: Menopause induces oral bone loss, leading to various oral diseases. Mastication importantly affects bone metabolism in the jawbone. OBJECTIVE: To analyze the effect of enhanced masticatory force on osteoprotegerin (OPG), receptor activator of nuclear factor kappa B ligand (RANKL), and mechano-growth factor (MGF) in alveolar bone of ovariectomized rats and to study the mechanics mechanism of the alveolar bone of ovariectomized rats response to enhanced masticatory force. METHODOLOGY: Thirty Sprague Dawley rats were randomly divided into three groups: sham-operation group (fat around the removed ovary + normal hard diet), model group (ovariectomy + normal hard diet), and experimental group (ovariectomy + high hard diet). It was a 2-month experiment. Enzyme-linked immunosorbent assay (ELISA) detected serum estradiol (E2), osteocalcin (BGP) and alkaline phosphatase (ALP) in rats. Bone histomorphometric indices in the third molar region of maxilla were detected by micro-CT; protein expressions of OPG, RANKL, and MGF in the third molar region of maxilla was detected by Western blot; and gene expression of OPG, RANKL, and MGF in the third molar region of maxilla was detected by Quantitative Real-Time PCR. RESULTS: Comparing with model group, serum E2 in experimental group increased but not significantly, serum BGP and serum ALP in experimental group decreased but not significantly, OPG in experimental group in alveolar bone increased significantly, RANKL in experimental group in alveolar bone decreased significantly, RANKL/OPG ratio in experimental group decreased significantly, MGF in experimental group in alveolar bone increased significantly, bone volume to total volume fraction increased significantly in experimental group, trabecular thickness increased significantly in experimental group, and trabecular separation decreased significantly in experimental group. CONCLUSION: Enhanced masticatory force affected the expression of OPG, RANKL, and MGF in alveolar bone of ovariectomized rats, improved the quality of jaw bone of ovariectomized rats, and delayed oral bone loss by ovariectomy.


Asunto(s)
Proceso Alveolar/fisiopatología , Fuerza de la Mordida , Factor I del Crecimiento Similar a la Insulina/análisis , Osteoprotegerina/análisis , Ovariectomía , Ligando RANK/análisis , Fosfatasa Alcalina/sangre , Animales , Western Blotting , Ensayo de Immunospot Ligado a Enzimas , Estradiol/sangre , Femenino , Osteocalcina/sangre , Ratas Sprague-Dawley , Reacción en Cadena en Tiempo Real de la Polimerasa , Microtomografía por Rayos X
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