Bite force Research Papers - Academia.edu (original) (raw)

2025, The European Journal of Orthodontics

The aim of this study was to determine the occlusal bite force (OBF) changes, at the incisal and molar regions, after orthodontic treatment with functional appliance therapy in preadolescent subjects. Materials and methods: OBF was measured for patients (17 females and 16 males) before and after the treatment with Andresen functional appliance for an average period of 9 months (mean age was 11.8 ± 1.1 years). Three variables were registered; maximum OBF at molar region and the average of three readings at the molar (AOBF) and incisal regions (IOBF). The same variables were measured in two occasions for a matching non-treated control group with a period of 9 months between the two measurements. Results: No significant changes were seen in the OBF measured parameters in the control group. There was a reduction in all measured parameters. The mean reduction in maximum OBF was 76.1 ± 12.4 N (P < 0.001), 58.5 ± 13.0 N in AOBF (P < 0.001), and 69.3 ± 11.6 N IOBF (P < 0.001). Conclusions: Treatment with functional appliance caused a significant reduction in OBF immediately after treatment.

2025, The European Journal of Orthodontics

This study was carried out to record maximum occlusal bite force (MOBF) among different dentition stages in children and to study the relation of occlusal bite force to weight, height, and gender. A total of 1011 children (500 females and 511 males) aged from 3 to 18 years were examined. The subjects were divided into 5 groups according to their dentition stage as the following:-early primary dentition stage (100 males and 100 females, average age was 3.37 ± 0.23 years), late primary dentition stage (104 males and 100 females, average age was 5.86 ± 1.15 years), early mixed dentition stage (100 males and 100 females, average age was 8.15 ± 0.67 years), late mixed dentition stage (100 males and 100 females, average age was 9.97 ± 0.86 years ), and permanent dentition stage (107 males and 100 females, average age was 14.03 ± 2.14 years). Occlusal bite force was measured using a hydraulic occlusal force gauge. The means of MOBF for the different dentition stages were:-176 N in early primary stage, 240 N in late primary stage, 289 N in early mixed stage, 433 N in late mixed stage, and 527 N in the permanent dentition stage, respectively. Gender differences were detected in groups 2, 3 and 4. Height and age signifi cantly correlated with the MOBF in all dentition stage groups except group 1. In conclusion, the MOBF increased with age. Age, gender, and height were signifi cant predictors of the MOBF.

2025, The European Journal of Orthodontics

This study was carried out to record maximum occlusal bite force (MBF ) in Jordanian students with three different facial types: short, average, and long, and to determine the effect of gender, type of functional occlusion, and the presence of premature contacts and parafunctional habits on MBF. Sixty dental students (30 males and 30 females) were divided into three equal groups based on the maxillomandibular planes angle (Max/Mand) and degree of anterior overlap: included short-faced students with a deep anterior overbite (Max/Mand ≤ 22 degrees), normal-faced students with a normal overbite that served as the controls (Max/Mand = 27 ± 5 degrees), and long-faced students with an anterior open bite (Max/Mand ≥ 32 degrees). Their age ranged between 20 and 23 years. MBF was measured using a hydraulic occlusal force gauge. Occlusal factors, including the type of functional occlusion, the presence of premature contacts, and parafunctional habits, were recorded. Differences between groups were assessed using a t -test and analysis of variance. The average MBF in Jordanian adults was 573.42 ± 140.18 N. Those with a short face had the highest MBF (679.60 ± 117.46 N) while the long-face types had the lowest MBF (453.57 ± 98.30 N; P < 0.001). The average MBF was 599.02 ± 145.91 in males and 546.97 ± 131.18 in females ( P = 0.149). No gender differences were observed. The average MBF was higher in patients with premature contacts than those without, while it did not differ in subjects with different types of functional occlusion or in the presence of parafunctional habits.

2025, Journal of Oral Rehabilitation

Objective: This study aims to verify the associations among sleep bruxism (SB), sleep arousal (SA), and concurrent body movements. Material and Methods: Subjects underwent a standard overnight polysomnography test and audio-video recordings. Sleep quality was evaluated according to the Rechtschaffen and Kales criteria, while SA was determined as per the American Sleep Disorders Association criteria. Analyses were performed by an external institution after masking of the subjects' information. SB was assessed based on the presence/absence of rhythmic masticatory muscle activity (RMMA) episodes, which were identified by using electromyography of the masseter muscle. The observed simultaneous movements included lower leg movement (LLM), swallowing, face scratching, head movement, body movement, eye blinking, coughing, licking, sighing, body scratching, lip sucking, somniloquy, and yawning. The LLM was determined visually, as well as through an increase in the tibialis electromyogram signal. Other movements were visually assessed using audio-video recordings. The incidences of all the simultaneous movements were compared between RMMA with intercurrent SA (SAwRMMA; RMMA episode derived from a masseter electromyogram showing more than 10% of maximum voluntary contraction) and SA without RMMA (SAw/oRMMA). Results: Fourteen subjects were included in this study (females/males: 4/10, mean age: 31.5 ± 5.7 years). Among these, LLM, swallowing, body movement, licking, body scratching, and lip sucking were frequently observed in SAwRMMA episodes than in SAw/oRMMA episodes, significantly. However, the non-specific simultaneous movements were higher observed in SAw/oRMMA episodes than that in SAwRMMA. Our results suggest that SB is concurrently activated with LLM in relation to arousal.

2025, Animal Behaviour

Closely related lacertid lizards (Eremias, Nucras) in the Kalahari desert differ in patterns of foraging behaviour. Some species are relatively sedentary ('sit-and-wait'), whereas others are more active ('widely-foraging') predators. We determined whether whole-animal locomotor capacities (cruising endurance on a treadmill, initial speed and maximum burst speed in a racetrack, and sprint endurance in a torus-shaped track) correlated with interspecific differences in foraging behaviour. Two of three widely-foraging species had greater cruising endurance, greater sprint endurance, but lower burst speed than did a sit-and-wait species. However, the two species that sprinted quickly also had limited endurance, and vice versa. Pre-feeding negatively influenced endurance but not sprint capacity. Theoretical models of foraging behaviour should recognize that ectotherms have limited endurance, that there can be a trade-off between s ~e e d and endurance, and that pre-feeding can reduce some aspects of locomotor capacity.

2025, Brazilian Dental Science

Objective: Evaluate the prevalence of Temporomandibular Disorder in patients with full double prosthesis. Material and Methods: The sample was composed of 40 volunteer patients, aged between 34 and 92 years, with upper and lower dentures, assisted at the Total Prosthodontics Clinic of the School of Dentistry at the Federal University of Juiz de Fora. Patients were evaluated by a single trained examiner and the diagnosis of TMD was established from the axis I of the RDC/TMD. Results: The prevalence of TMD in the sample was 42.5%, and most patients were female. Although there was no statistical significance between the time of use of the prosthesis and the presence of TMD was found, there was a correlation between time without use of prosthesis and the presence of disc displacement. Conclusion: According to the methodology applied and the results of this study, it can be concluded that there was a considerable prevalence of TMD in patients with double dentures, but there was no correl...

2025, Journal of clinical and diagnostic research : JCDR

The purpose of this study was to evaluate the mean maximum bite force in dentulous and edentulous individuals with Angle's class-I occlusion and to assess the…

2025, Journal (Canadian Dental Association)

A literature review of longevity and clinical performance of IPS-Empress restorations is presented. A MEDLINE search was conducted in fall 2000. Selection criteria were set so as to identify suitable clinical trials that were published in full and that had lasted more than 2 years. A total of 6 clinical trials on the performance of IPS-Empress inlays and onlays and a total of 3 clinical trials on the performance of IPS-Empress crowns were identified. Survival rates for IPS-Empress inlays and onlays ranged from 96% at 4.5 years to 91% at 7 years; most failures were due to bulk fracture. IPS-Empress crowns had a survival rate ranging from 92% to 99% at 3 to 3.5 years; crown failure was also mainly due to fracture. Dentists should inform their patients about these survival rates when offering such treatment. The use of IPS-Empress crowns in the posterior of the mouth is not recommended until the results of more long-term clinical trials are available.

2025, Nihon Gaku Kōkō Kinō Gakkai zasshi

This study assessed how the location of the tapping point is affected by changing the head position. An intra-oral tracing device consisted of a metal tracing plate and a central bearing pin was used in five fully dentate subjects. The tracing plate was fixed to the maxillary part of the device parallel to the occlusal plane. The central bearing pin was fixed to the mandibular part of the device and was located at the midpoint of a line connecting the bilateral first molars. The pin was placed perpendicular to the tracing plate. The appliance was inserted in the mouth and the subject was asked to perform tapping movements with the head Camper and Frankfort plane placed horizontally. The tapping movements (n=30) were made at a 30 mm-range of motion, and the incisal and condylar points were tracked with a 6-degree-of-freedom jaw movement tracking system (TRIMET; Tokyo Shizaisha Co., Japan). The antero-posterior distribution of 30 tapping points and their mean position from intercuspal position were analyzed in incisor and condylar points between two head positions. Result revealed that the condylar points corresponding to the tapping points converged into a small area when the head was positioned with the Camper plane horizontal. However, in both head positions, condylar points were located anteriorly from the intercuspal position. From the results, it can be concluded that head position has it's effects on the distribution and mean position of tapping points. In addition, it can be suggested that from the distribution of scattered tapping points, the head should be positioned with the Camper plane horizontal to record the tapping points at a convergent area.

2025, The Journal of Japanese Society of Stomatognathic Function

2025, Journal of Anatomy

During mastication, various biomechanical events occur at the mammalian jaw symphysis. Previously, these events have been studied in the static environment, or by direct recording of surface bone strains. Thus far, however, it has not been possible to demonstrate directly the forces and torques passing through the symphysis in association with dynamically changing muscle tensions. Therefore, we modified a previously published dynamic pig jaw model to predict the forces and torques at the symphysis, and related these to simulated masticatory muscle tensions, and bite, joint and food bolus forces. An artificial rigid joint was modelled at the symphysis, allowing measurements of the tri-axial forces and torques passing through it. The model successfully confirmed three previously postulated loading patterns at the symphysis. Dorsoventral shear occurred when the lower teeth hit the artificial food bolus. It was associated with balancing-side jaw adductor forces, and reaction forces from the working-side bite point. Medial transverse bending occurred during jaw opening, and was associated with bilateral tensions in the lateral pterygoid. Lateral transverse bending (wishboning) occurred at the late stage of the power stroke, and was associated with the actions of the deep and superficial masseters. The largest predicted force was dorsoventral shear force, and the largest torque was a 'wishboning' torque about the superoinferior axis. We suggest that dynamic modelling offers a new and powerful method for studying jaw biomechanics, especially when the parameters involved are difficult or impossible to measure in vivo .

2025, Archives of Oral Biology

The morphology of bony trabeculae can indicate the loading conditions that predominate near joint surfaces. This study reports principal orientation, anisotropy, thickness, separation and density of trabeculae in the mandibular condyle of pigs. Condyles from slaughterhouse pigs were serially sectioned anteroposteriorly (n = 4), mediolaterally (n = 5) or horizontally (n = 4) at 0.8 mm using a diamond saw. Sections were viewed under a stereomicroscope and video-images of four sites per section were digitized. Anteroinferior sites had thicker, more widely spaced trabeculae than other sites, suggesting a concentration of stress. Anisotropy in the frontal plane was greater than in the sagittal or the horizontal planes, indicating a more consistent direction of loading in the frontal plane. Principal orientation in the frontal sections was perpendicular to the occlusal plane and did not differ among the sites. In the sagittal sections, trabeculae in :inferior sites were variably oriented, whereas those in superior sites sloped posterosuperiorly, possibly reflecting shearing loads resulting from translational movements. In the horizontal sections, the trabeculae were oriented perpendicular to the frontal plane, suggesting an anteroposterior component of loading. Compared to cancellous bone from other locations, the trabeculae of the mandibular condyle are robust and dense, strongly supporting the notion that the temporomandibular joint is heavily loaded.

2025, Journal of Oral Rehabilitation

While evidence exists to support the effectiveness of splints on conditions involving the masticatory musculature, few research projects have examined the results of long-term splint wear. The purpose of this study was to examine the function of the masticatory system over a 2-month time period of splint wear. Young adult female miniature pigs were divided into three groups: a control (C) group that wore no intraoral splint, a control splint (CS) group that wore a splint increasing bite height, and a protrusive splint (PS) group that wore a splint increasing bite height and moving the mandible anteriorly. Splints were worn constantly. Fine-wire needle EMG was performed prior to splint delivery and at 1 and 2 months post-splint delivery. Bilateral superficial masseters and zygomaticomandibularis (ZM, equivalent to deep masseter) muscles were monitored during normal feeding. Absolute EMG output, percentage output, and cycle timing were unaffected by chronic splint wear. However, chewing coordination was significantly changed in the splinted groups in both sessions post-splint delivery relative to baseline readings and to the C group (P < 0AE005). Trends indicate that the coordination of the PS group was more greatly altered than that of the CS group.

2025, Systematic Biology

Cat-like carnivorous mammals represent a relatively homogeneous group of species whose morphology appears constrained by exclusive adaptations for meat eating. We present the most comprehensive data set of extant and extinct cat-like species to test for evolutionary transformations in size, shape and mechanical performance, that is, von Mises stress and surface traction, of the mandible. Size and shape were both quantified by means of geometric morphometrics, whereas mechanical performance was assessed applying finite element models to 2D geometry of the mandible. Additionally, we present the first almost complete composite phylogeny of cat-like carnivorans for which well-preserved mandibles are known, including representatives of 35 extant and 59 extinct species of Felidae, Nimravidae, and Barbourofelidae. This phylogeny was used to test morphological differentiation, allometry, and covariation of mandible parts within and among clades. After taking phylogeny into account, we found that both allometry and mechanical variables exhibit a significant impact on mandible shape. We also tested whether mechanical performance was linked to morphological integration. Mechanical stress at the coronoid process is higher in sabertoothed cats than in any other clade. This is strongly related to the high degree of covariation within modules of sabertooths mandibles. We found significant correlation between integration at the clade level and per-clade averaged stress values, on both original data and by partialling out interclade allometry from shapes when calculating integration. This suggests a strong interaction between natural selection and the evolution of developmental and functional modules at the clade level. [Comparative methods; felidae mandible; finite element analysis; geometric morphometrics; morphological integration; sabertooth; structural performance]

2025, Benelux Congress of …

In an ecomorphological context bite force measurements are used as a proxy to estimate biting performance. We compared two approaches for gauging bite force in a study of inter-and intraspecific variation in African mole-rats. Fukomys (syn. Cryptomys) are chisel-tooth diggers which excavate extensive tunnel systems along which they forage for geophytes. Their obligatory subterranean activities as well as agonistic encounters require an efficient jaw apparatus. Firstly in vivo measurements were compared with data obtained from a ...

2025, Rodent Biology and …

African mole-rats are chisel-tooth digging subterranean rodents. Digging large tunnel systems and foraging for geophytes requires an efficient jaw apparatus. We studied bite force in several species of the Fukomys radiation from the Zambezian region to assess the extent of variation in biting performance. Maximal bite force was measured using a Kistler isometric force transducer. Data were related to skull size and skull shape variation, which was estimated with landmark-based geometric morphometrical tools. Results: 1. we show ...

2025, Naturwissenschaften

Although several neurobiological and genetic correlates of aging and behavioral development have been identified in social insect workers, little is known about how other age-related physiological processes, such as muscle maturation, contribute to task performance. We examined post-eclosion growth of three major muscles of the head capsule in major and minor workers of the ant Pheidole dentata using workers of different ages with distinct task repertoires. Mandible closer muscle fibers, which provide bite force and are thus critical for the use of the mandibles for biting and load carrying, fill the posteriolateral portions of the head capsule in mature, older workers of both subcastes. Mandible closer fibers of newly eclosed workers, in contrast, are significantly thinner in both subcastes and grow during at least the next 6 days in minor workers, suggesting this muscle has reduced functionality for a substantial period of adult life and thus constrains task performance capability. Fibers of the antennal muscles and the pharynx dilator, which control antennal movements and food intake, respectively, also increase significantly in thickness with age. However, these fibers are only slightly thinner in newly eclosed workers and attain their maximum thickness over a shorter time span in minors. The different growth rates of these functionally distinct muscles likely have consequences for how adult P. dentata workers, particularly minors, develop their full and diverse task repertoire as they age. Workers may be capable of feeding and interacting socially soon after eclosion, but require a longer period of development to effectively use their mandibles, which enable the efficient performance of tasks ranging from nursing to foraging and defense.

2025, Clinical Oral Implants Research

Objective: The task of this working group was to update the existing knowledge base regarding the prevalence of peri-implant tissue destruction, the role of occlusal overload, and the outcome of non-surgical and surgical treatment. The literature was systematically searched and critically reviewed. Four manuscripts were presented in key areas deemed to be essential for the current understanding of the magnitude of the clinical entity peri-implantitis. The role of overload as an etiological component was reviewed. Also available data on the results from non-surgical and surgical interventions for the control of tissue destruction were presented. The consensus statements following plenary session approval, clinical implications, and directions for future research based on the group discussions are presented in this article. The results and conclusions of the systematic review process are presented by the respective authors in the subsequent papers.

2025

RESUMEN Introduccion: El estado edentulo representa una agresion a la integridad del sistema masticatorio con secuelas biologicas, esteticas y funcionales. El numero de pacientes edentes en el mundo es significativo. En un analisis comparativo del estado de salud bucal realizado en varias provincias del pais, la provincia Granma resulto la mas necesitada de protesis dental. Objetivos: Determinar la necesidad de protesis estomatologicas en pacientes mayores de 15 anos pertenecientes al consultorio medico de familia #14 del Soviet, Consejo Popular Mabay en el ano 2014. Metodo: Se realizo una investigacion descriptiva de corte transversal. Segun Sampieri, de 862, la muestra quedo constituida por 485 individuos, seleccionados por muestreo estratificado aleatorio simple y por sorteo. Se tuvieron en cuenta diferentes variables como la edad, el sexo, tipo de protesis necesitada, necesidad de protesis estomatologica sentida y no sentida. Resultados: La necesidad de protesis estomatologica ...

2025, BioMed Research International

Stress may affect the function of all the components of the masticatory system and may ultimately lead to differentiated symptoms and finally to systemic and structural dysfunctions. Objective. To determine the effect of stress on the masticatory muscles function in young healthy adults. Material and Methods. A total of 201 young, Angle's first class, healthy volunteers, 103 female and 98 male, in the age between 18 and 21 years were recruited into the study. All the participants underwent clinical examination according to the Slavicek scheme, questionnaire survey according to Perceived Stress Scale, and assessment of masticatory muscles function in central occlusion. Results. Symptoms of masticatory system dysfunction were found in the group of 86 subjects (46,24%). All the muscles activity in central occlusion was comparable in female and male groups. Mean values of masseters activities in the group of low stress subjects (75,52 𝜇V ± 15,97) were statistically different from the groups with medium (82,43 𝜇V ± 15,04) and high (81,33 ± 12,05) perceived stress (𝑃 < 0.05). Conclusion. Chronic stress may reveal or exacerbate symptoms of masticatory dysfunction.

2025, International Journal of Oral and Maxillofacial Surgery

Objective: To investigate the influence of maxillary alveolar bone on the stress distribution of zygomatic implants in an extra-sinus position. Materials & Methods: A threedimensional finite element model was created based on a CT scan of an edentulous female patient. Two zygomatic implants were modelled and placed in the skull in an extrasinus position. These were supported by the zygomatic bone and the maxillary alveolar bone and were connected by a fixed bridge. This model was duplicated, and the area of the maxillary alveolar bone supporting the implants was removed. Occlusal and lateral forces were applied to both models and the maximum von Mises stresses were recorded. Results: Higher maximum stresses were noted in the model with no alveolar support. Occlusal stresses were higher than lateral stresses in the model with no alveolar support, while occlusal stresses were lower than lateral stresses in the model with alveolar support. Low stresses were noted in the zygomatic bone in both models. Conclusion: Maxillary alveolar bone support is beneficial in the distribution of forces for zygomatic implants placed in an extra-sinus position.

2025, International journal of oral and maxillofacial surgery

The objective of this study was to investigate the influence of maxillary alveolar bone on the stress distribution of zygomatic implants. A three-dimensional finite element model was created of half of a skull. Two zygomatic implants were modelled, placed in the skull supported by the zygomatic bone and the maxillary alveolar bone and connected by a fixed bridge. This model was duplicated, and the area of the maxillary alveolar bone supporting the implants was removed. Occlusal and lateral forces were applied to both models and the maximum von Mises stresses were recorded. Higher maximum stresses were noted in the model with no alveolar support. Occlusal stresses were higher than lateral stresses in the model with no alveolar support. Low stresses were noted in the zygomatic bone in both models. In conclusion, maxillary alveolar bone support is beneficial in the distribution of forces for zygomatic implants.

2025, International Journal for Numerical and Analytical Methods in Geomechanics

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2025, Journal of Prosthetic Dentistry

Statement of problem. The mandibular posterior 3-unit fixed partial denture (FPD) is a conventional prosthodontic therapy and presumably has an effect on the direction and magnitude of occlusal forces and, thus, on the biomechanical environment of the mandible, which may in turn affect bone structure. However, the impact of FPD therapy on mandibular biomechanics is unknown. Purpose. The purpose of this study was to test the hypothesis that 3-unit FPD therapy alters strain patterns in the mandible during loading. Material and methods. Four human cadaver mandibles missing first molars were bilaterally fixed and artificially loaded on each tooth individually. Surface cortical bone strains were measured with multiple strain gauges during loading of up to 250 N. Next, 3-unit FPDs with a chamfer finish line were fabricated using Type IV gold alloy. Strain measurements were conducted in the same manner to assess differences in strain patterns before and after therapy. Paired-sample tests for metric and angular data were used to assess difference in strain pattern before and after therapies (a=.05). Results. When loading was applied on the teeth not involved in FPD therapy, no differences were found before and after FPD placement. When the posterior retainers were loaded, the strain distribution differed (P=.01); on the buccal cortices, strain levels increased posteriorly but decreased significantly anteriorly. However, these differences were less than 100 me, and the overall deformation pattern of the mandible after the FPD therapy was similar to that before FPD therapy. Strain distributions when the pontic was loaded were similar to those when the posterior retainer was loaded. Three-unit FPD therapy did not alter the overall deformation pattern of the mandible during loading. (

2025, Journal of Oral and Maxillofacial Surgery

2025, Dental Materials

Objectives: The aim of this study was to investigate the creep, stress relaxation and strain rate behavior of human root dentin under compressive loading. Methods: Cylindrical root dentin samples of 3.5 mm outer diameter, 1.5 mm internal canal diameter and 6±10 mm long were prepared from freshly extracted teeth. The samples were tested in a closed-loop servohydraulic testing machine at constant load or displacement, and varied strain rate. In vivo strain rates were estimated using strain gauges bonded to human teeth. Results: A family of creep curves, determined at different loads within dentin's elastic region, was found to be consistent with a material having linear viscoelastic behavior. A positive correlation (r 2 0.79, P , 0.001) was found between creep rate and stress. Young's modulus (E) was found to be a function of the strain rate with rates of loading in the range 10±500,000 Ns 21 . Loading at constant displacement showed stress to be a decreasing function of time (i.e. stress relaxation). Signi®cance: Dentin showed linear-viscoelastic behavior under various conditions of compressive loading. Time dependent properties of dentin should be taken into account in restorative dentistry.

2025

Introduction: Periodontal ligament, tooth, and alveolar bone react as deformable entities under loads. Stresses in the PDL believed to be the starting factor in tooth movement, and various types of stresses are transmitted to bone through the PDL. Therefore, it is essential to consider these tissues as continuous unit to help in quantitative assessment of stress and strain in periodontium. FEM provides an approximate solution for response of the 3-dimensional (3D) structures to applied external loads under certain boundary conditions. Materials and Methods: Total of four models were created i.e. two models with retraction by elastomeric chain and two models with retraction by NiTi coil spring with help of implant placed at 3 mm and 5 mm height from alveolar crest. Results were represented in the form of stress diagrams. Results: En-masse retraction with elastomeric chain showed more periodontal stresses. Increasing the height of mini-screw implant was also associated with increase in periodontal stresses. Conclusions: For the same height of mini-screw implant, en masse retraction with elastomeric chain demonstrated a higher amount of periodontal stresses as compared to NiTi coil springs. The highest stress throughout the PDL was always present around cervical area in both types of en-masse retraction, indicating that cervical area, apart from apex, bears the most loads and might be considered as susceptible area for potential tissue damage. Increasing height of mini-screw implant more gingivally associated with more amount of periodontal stresses in both types of en-masse retraction.

2025

N 5 | Setembro • Outubro | 2006 | 12 PR ÓT ES E SO BR EI M PL AN TE Infelizmente, apesar de todas as mudanças de paradigmas nos campos de prevenção e tratamento em saúde bucal, ainda há uma grande parcela da população mundial que faz uso ou necessita de próteses totais. Segundo o Levantamento Epidemiológico em Saúde Bucal, realizado em 1986, em zonas urbanas no Brasil, 50% da população entre 50 e 59 anos, maior faixa etária pesquisada, eram edêntulos e 72% usavam ou necessitavam de prótese total37. Mais recentemente, de acordo com o relatório do Levantamento das Condições de Saúde Bucal da População Brasileira em 2003 (SB Brasil), 57,91% das pessoas entre 54 e 64 anos usam prótese total superior e 24,84%, total inferior38. A atual população idosa no Brasil configura um contingente de quase 15 milhões de pessoas, podendo chegar a mais de 30 milhões num período de 20 anos, segundo dados de 2000 do IBGE39. No que tange as ações programáticas de saúde bucal voltadas à terceira idade, es...

2025, Acta Palaeontologica Polonica

Ornithosuchids are a Late Triassic pseudosuchian archosaur group, consisting of four species (three from South America, and one from Scotland). All of them have triangular skulls with a protruding premaxilla, large nostrils, an extensive diastema in their narrow snout, a short jaw that does not reach the anterior end of the skull, and serrated posteriorly curved teeth. For this clade, carnivorous and scavenger habits have been previously proposed. Within the Ornithosuchidae, Riojasuchus tenuisceps (from Argentina) has the most morphologically extreme characteristics. Based on CT scans of the preserved skulls we generated a 3D model, and over this, we estimated the volumes of the adductors and abductor muscles and the force exerted by each. From these data we built the finite element model and measured the bite force (1.8-2.3 kN). Lateral, tractive, and torsional forces were applied to the end of the snout to evaluate the structural response of the skull during feeding. The results show that R. tenuisceps could resist tractive and torsional stresses better than lateral stress. Additionally, we analysed the peculiar morphological characteristics of the skull and their functional implications. We observed that the upper and lower dental rows were laterally separated from each other, preventing the generation of a cutting line during occlusion, and therefore, R. tenuisceps would have fed on small-sized prey that it could swallow whole. The curved premaxilla and the short mandible would not allow it to bite with the tip of the snout (ruling out the scavenging hypothesis), but were instead more adequate to capturing prey suspended in a fluid. This set of results allows us to propose that R. tenuisceps could have had a zoophagous diet and a wading habit, being able to feed on fish, amphibians, or any small animals that they could catch from the shoreline. K ey w o r d s : Archosauria, biomechanics, feeding habits, finite element model, bite force estimation.

2025, MDPI

Background: The advancement of dental implants marks a significant milestone in modern dentistry, offering an effective solution for tooth replacement while improving both functionality aesthetics. Despite their high success rates, dental implants are susceptible to various complications, including mechanical issues. Among the most common mechanical complications is implant screw loosening and fracture, which compromises the structural integrity of the dental implant and may lead to implant failure. Aim of study: To establish a protocol for managing implant abutment screw fractures by removing the fractured part without compromising the implant or its functionality. Methodology: A case highlights the loosening of implant screws as a critical concern in restorative dentistry. The fractured abutment screw was successfully retrieved using an ultrasonic tip, presenting an effective and straightforward sequential protocol for retrieving fractured abutment screws while preserving the integrity of the implant. Results: Using The ultrasonic tip technique demonstrates a highly significant impact by providing a simple, effective, conservative, noninvasive, and predictable protocol for removing fractured screw abutments from dental implants. Furthermore, this technique enables clinicians to reuse the same implant without causing surgical trauma or imposing any financial burden on the patient. Conclusion: Abutment screw fractures represent a mechanical failure associated with dental implants. Retrieving fractured abutment screw without causing damage to the internals of the implants poses a significant challenge for clinicians, often requiring considerable time and effort to address the underlying cause of the fracture.

2025, The International Journal of Prosthodontics

Purpose: To measure the vertical occlusal forces transmitted through crowns made of different restorative materials onto simulated peri-implant bone. Materials and Methods: The study was conducted using a masticatory robot that is able to reproduce the mandibular movements and forces exerted during mastication. During robot mastication, the forces transmitted onto the simulated peri-implant bone were recorded using nine different restorative materials for the simulated single crown: zirconia, two glass-ceramics, a gold alloy, three composite resins, and two acrylic resins. Three identical sample crowns for each material were used. Each crown was placed under 100 masticatory cycles, occluding with the flat upper surface of the robot to evaluate the vertical forces transmitted. Two-way analysis of variance was used. Alpha was set at .05. Results: The statistical evaluation of the force peaks recorded on the vertical z-axis showed mean values of 641.8 N for zirconia; 484.5 N and 344.5 N, respectively, for the two glass-ceramics; 344.8 N for gold alloy; 293.6 N, 236 N, and 187.4 N, respectively, for the three composite resins; and 39.3 N and 28.3 N, respectively, for the two acrylic resins. Significant differences were found between materials (P < .0001), except for the comparison between gold alloy and one of the glass-ceramics. Conclusion: Composite and above all acrylic resin crowns were more able to absorb shock from occlusal forces than crowns made of zirconia, ceramic material, or gold alloy.

2025, Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale

2025, Journal of Oral Implantology

Immediate loading of newly placed dental implants is a consideration when attempting to meet patients' demands. However, immediate loading may induce implant failure to osseointegrate, particularly in the case of a patient who can generate a biting force that can reach approximately 1300 Newtons (N) in the posterior jaws. The range of biting forces that prevent osseointegration of newly placed implants is currently unknown. However, it is suspected that osseointegration may fail if an implant is luxated in bone more than 50 lm, in which case fibrous tissue will be formed instead of bone. This pilot study was focused on finding the amount of horizontal off-axial force required to move a nonosseointegrated 4.3 3 13-mm implant 50 lm. The initial data show that the amount of horizontal force required to displace such an implant by 50 lm was on the order of 150 N. Assuming that the angle between the direction of the biting force and the vertical lies between 08 and 208, our data show that a 4.3 3 13-mm implant may fail to osseointegrate for biting forces that are as low as 440 N. One implication of our study is that implants having smaller diameters may move and fail to osseointegrate for even lower biting forces.

2025, Diversity

Meta-Analysis Reveals Behavioral Plasticity, Not Agonistic Behavior, Facilitates Invasion of Brown Anoles (Anolis sagrei) and Replacement of Green Anoles (Anolis carolinensis).

2025

This paper presents the finite element analysis of fractured Femur bone with functionally graded bone plate system. CT (Computerized Tomography) scan data has been used for the modeling of femur bone and the corresponding material properties are assigned using Mimics software. SOLID 186 element is used for analysis. The fracture fixation plate used for the present analysis is composed of Functionally Graded material (FGM) which is modeled by using Solid works CAD software. The FG bone plate is considered to be composed of different layers of homogeneous material. By using a power law the volume fraction of the material is calculated by taking its variation in the thickness direction (z). consequently, the essential properties are calculated for the homogenous layers. Validation of the developed model is carried out by comparing the numerical results available in literature. The modal analysis has been carried out and the modal parameters such as natural frequency and their associate...

2025, Neuroscience Letters

Spectral analysis of single-unit discharges, multi-unit EMG and muscle force during voluntary quasi-sinusoidal isometric contractions of two hand muscles revealed corresponding modulations of the firing rates of motor units at the frequency of the force oscillation. These rate modulations were correlated; and they showed a phase advance over the force oscillation, which is consistent with a cause-effect relationship between changes in firing rate and variations in force. These effects, observed over wide ranges of modulation amplitudes and frequencies, confirm the role of rate coding in the generation of time-varying muscle contractions; and they support the idea that during voluntary contraction of a given muscle, the motoneuron pool is subject to a common drive.

2025, Journal of Oral and Maxillofacial Surgery

This in vitro investigation was developed with the purpose of comparing the biomechanical features of 3 different methods of rigid internal fixation for sagittal split ramus osteotomies for mandibular advancement. Materials and Methods: Rigid internal fixation techniques included a 4-hole plate and 4 monocortical screws (miniplate group), a 4-hole plate and 4 monocortical screws with 1 additional bicortical positional screw (hybrid group), and 3 bicortical positional screws in a traditional inverted-L pattern (inverted-L group). Screws and miniplates were made of titanium and from a 2.0-mm system (MDT, Rio Claro, SP, Brazil). Sixty polyurethane replicas of human hemimandibles (Nacional, Jaú, SP, Brazil) were used as substrates, simulating a 5-mm advancement surgery by a sagittal split ramus osteotomy. They were adapted to a test support, and were submitted to lateral torsional forces on the buccal molar surface and vertical cantilever loading on the incisal edge by an Instron 4411 mechanical testing unit (Instron, Norwood, MA) for recording peak loading at 1 mm, 3 mm, 5 mm, and 10 mm of displacement. Each group was formed by 10 replicas, subjected to a linear noncyclical testing only once. Means and standard deviation were analyzed using analysis of variance and Tukey tests, with a 5% level of significance. Testing failures were also recorded. Results: The miniplate group showed lowest load peak scores (P Ͻ .01) when compared with the other fixation techniques, irrespective of the direction of force. The inverted-L group showed higher resistance (P Ͻ .01) than the hybrid group when vertical forces were applied. For molar load, the hybrid and inverted-L groups showed no significant difference. Conclusions: For mandibular advancement surgery of 5 mm, it was concluded that the rigid internal fixation technique for sagittal split ramus osteotomies based on 3 bicortical screws in the inverted-L pattern was the most stable in a laboratory environment. Furthermore, the results suggested that installation of a bicortical positional screw in the retromolar region may significantly optimize the resistance of the miniplate and monocortical screw fixation.

2025, Journal of oral rehabilitation

The aims of this study were to examine the change of occlusal contact area following the increment of clenching intensity using silicone materials and electromyography (EMG) in normal subjects and to compare direct intra-oral examination with indirect examination using dental casts mounted by means of two impression methods. Participants were 7 men and 5 women with no more than one missing tooth per quadrant and no pain in the head and neck region. During the task, intercuspal position was maintained with minimal force, 20% maximum voluntary contraction (MVC) and 40% MVC using electromyography visual feedback. Three types of occlusal contact examinations were performed with the aid of blue silicone material in randomised order: (i) intra-oral direct occlusal contact examination (DE), (ii) indirect occlusal contact examination with dental casts using conventional impression method (IEC) and (iii) using occlusal impression method (IEO). Total occlusal contact area during DE and IEO si...

2025, Journal of Oral Rehabilitation

2025, Journal of Electromyography and Kinesiology

Purpose: To understand the effects of HIV type 1 on the function of the masticatory muscles. Methods: Sixty individuals were selected from both genders, aged between 22 and 57 years (mean 36.77 ± 9.33 years), and divided into two groups: Group HIVG, 30 individuals with HIV subtype 1, and Group CG, 30 healthy individuals (control group). The individuals were submitted to assessments of their masticatory muscle activity, biting strength and thickness of the masticatory muscles by means of electromyography, maximal molar bite force and ultrasound imaging, respectively. The resultant data were statistically analyzed by t-tests (p < 0.05). Results: The HIVG normalized EMG data from a mandibular rest position, protrusion, right and left laterality movement of the jaw showed that HIVG presented a relative increase in EMG activity compared to the CG. The HIVG had a lower masticatory cycle ability while chewing Parafilm M Ò , Raisins and Peanuts when compared to CG. During rest conditions, the ultrasound images showed a greater average muscular thickness in the right and left temporal region compared to CG. Upon maximal voluntary contraction, an increased average thickness was seen in the temporalis muscles and left sternocleidomastoid muscle when compared to the CG. Conclusion: Based on the results of this research, it can be concluded that individuals with acquired immunodeficiency syndrome showed muscular changes related to the stomatognathic system, especially concerning EMG activity and muscle thickness.

2025, American Journal of Orthodontics and Dentofacial Orthopedics

2025, American Journal of Physical Anthropology

ABSTRACTObjectivesMaximum ingested food size (Vb) is an empirically tested performance variable that can shed light on feeding energetics and adaptation in the masticatory system. Until now, this variable had been tested in strepsirrhines alone among primates. Here, we present the first data on Vb in a broad sample of anthropoid primates and describe scaling patterns.Materials and MethodsVb data on anthropoids were collected under captive conditions at the Philadelphia Zoo and compared with published data on strepsirrhines. Data on Vb were scaled against individual body mass and were compared with experimentally determined toughness and stiffness values for the test foods.ResultsUnlike in strepsirrhines, where essentially Vb scales isometrically with body mass, Vb in anthropoids scales with negative allometry. There is a significant effect of food material properties on Vb, although bite size in anthropoids varies less based on food properties than in strepsirrhines. Large folivorou...

2025, The Anatomical Record

Increasingly, analyses of craniodental dietary adaptations take into account mechanical properties of foods. However, masticatory muscle fiber architecture has been described for relatively few lineages, even though an understanding of the scaling of this anatomy can yield important information about adaptations for stretch and strength in the masticatory system. Data on the mandibular adductors of 28 specimens from nine species of felids representing nearly the entire body size range of the family allow us to evaluate the influence of body size and diet on the masticatory apparatus within this lineage. Masticatory muscle masses scale isometrically, tending toward positive allometry, with body mass and jaw length. This allometry becomes significant when the independent variable is a geometric mean of cranial variables. For all three body size proxies, the physiological cross‐sectional area and predicted bite forces scale with significant positive allometry. Average fiber lengths (FL...

2025, Clinical Materials

c) Parafunctional habits, which increase time, magnitude, direction, and distribution of the forces affecting bone to implant contact. Implant-related factors: a) Implant macro design (implant body, length and diameter, threads shape, pitch, lead, depth and width, and crest module), implant design is mainly responsible for 1-increase the surface area of the implant, 2-decrease the stress in addition to 3-distributing the forces on the bone and convert the stresses into favorable compressive stresses. b) Chemical composition and biomaterial of the implant and its relation to biocompatibility, enhancing healing, modulus of elasticity. c) Implant surface treatment and coatings (surface topography), responsible for increase the surface area of the BIC, decrease the stresses, enhance adhesion qualities to the bone-implant interface at initial healing.

2025, Open Journal of Stomatology

The prevalence of torus mandibularis, Eagle's syndrome and parafunctional activity was reported to be higher in patients with temporomandibular joint dysfunction and might be useful as an indicator of increased risk of temporomandibular disorders. This study case report was to evaluate a 62-year-old female patient, with limited mandibular and cervical movements, articular and muscular pain, ear fullness, irritation of the lingual mucosa, discomfort associated with movement of her tongue, involving temporomandibular dysfunction, torus mandibularis and Eagle's syndrome. The treatment comprehended the collection of data of Helkimo's Clinical Dysfunction Index, electromyographic activity of the masseter and temporalis muscles in rest position and bite force, masticatory efficiency, speech evaluation and oclusal splint, after the excision of the stylohyoid process and mandibularis torus. The authors found a decrease in electromyographic activity of masticatory muscles, a reduction of painful symptoms throughout the region muscular and joint pains, an increase in the amplitude of mandibular movements, an improvement in masticatory efficiency and an increase in bite force.

2025

In this paper I describe the jaw adductor musculature in colubrid snakes that formerly belonged to the genus Elaphe Fitzinger. The group studied shows a high level of homoplasy, and particular lineages exhibit a mixture of advanced and... more

2025, Journal of anatomy

Pliosaurs were among the largest predators in Mesozoic seas, and yet their functional anatomy and feeding biomechanics are poorly understood. A new, well-preserved pliosaur from the Kimmeridgian of Weymouth Bay (UK) revealed cranial adaptations related to feeding. Digital modelling of computed tomography scans allowed reconstruction of missing, distorted regions of the skull and of the adductor musculature, which indicated high bite forces. Size-corrected beam theory modelling showed that the snout was poorly optimised against bending and torsional stresses compared with other aquatic and terrestrial predators, suggesting that pliosaurs did not twist or shake their prey during feeding and that seizing was better performed with post-symphyseal bites. Finite element analysis identified biting-induced stress patterns in both the rostrum and lower jaws, highlighting weak areas in the rostral maxillary-premaxillary contact and the caudal mandibular symphysis. A comparatively weak skull c...

2025, Journal of Dental Research and Practice

2025

Introduction: Temporomandibular joint (TMJ) is a bi-condylar, and highly mobile, complex joint functioning harmoniously and performing important functions for human body. The purpose of this study was to evaluate the relationship between dentition and TM disorders in the IVF children of West Bengal. Material & Methodology: The prevalence of signs and symptoms related to temporomandibular disorders was examined in 137 IVF and 137 spontaneously conceived children with primary dentition, mixed and permanent dentition. A questionnaire was used in combination with the clinical examination. For comparison of proportions Z test was used. Results : The results showed that there was an increase in signs and symptoms from the primary to the mixed to permanent dentition group. There was no statistically significant difference in maximum mouth opening capacity among the groups. Conclusion : Similar kind of prevalence of signs and symptoms of temporomandibular disorders of IVF & spontaneously co...