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1.
BMC Oral Health ; 24(1): 561, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38745284

RESUMO

BACKGROUND: Prefabricated myofunctional appliance can guide tooth eruption, improve dentition alignment, correct myofunctional disorders and harmful oral habits. However, its application to skeletal discrepancy may result in unsatisfactory tooth inclination. This study aimed to construct a novel appliance with overjet design to avoid this side effect and investigated its shape and mechanical changes under occlusion using three-dimensional finite element method. METHODS: We established three samples of prefabricated myofunctional appliances. The first one was edge to edge without overjet, and the outer shield of both jaws were flattened. The second one was 3 mm overjet with stepped the outer shield. The last one was 3 mm overjet, and the outer shield of both jaws were flatted, which meant the front wall of lower jaw was strengthened with bumper, termed as lower bumper. A complete dentition model was applied to the study. 150 N occlusal force was applied to each type of appliance and the deformation displacement and the changes in stress was recorded. RESULTS: The deformation was significant in the incisors regions, especially in the vertical and lateral dimensions. The maximum displacements of 3 mm overjet with step shield group were 7.08 mm (vertical), 3.99 mm (lateral), and 2.90 mm (sagittal), while it decreased to 3.92 mm(vertical), 1.94 mm (lateral), and 1.55 mm (sagittal) in overjet with bumper group. Moreover, the upper molar regions exhibited higher vertical and sagittal displacement in 3 mm overjet with step shield group, which were 3.03 mm (vertical) and 1.99 mm (sagittal), and the bumper design could decrease the maximum displacement to 1.72 mm (vertical) and 0.72 mm (sagittal). In addition, the Von Mises stress of appliances was analyzed, and results indicated that 3 mm overjet with step shield generated higher stress than other groups, with the maximum Von Mises stress was 0.9387 MP, which were 0.5858 and 0.5657 MP in edge to edge group and 3 mm overjet with lower bumper group, respectively. CONCLUSION: The prefabricated myofunctional appliances may cause deformation during occlusion. Compared to step shield group, the application of lower bumper exhibited better resistance to occlusal force.


Assuntos
Análise de Elementos Finitos , Desenho de Aparelho Ortodôntico , Humanos , Terapia Miofuncional/instrumentação , Terapia Miofuncional/métodos , Força de Mordida , Imageamento Tridimensional/métodos , Sobremordida/terapia , Estresse Mecânico , Mandíbula , Incisivo , Fenômenos Biomecânicos
2.
Codas ; 36(3): e20230203, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38695438

RESUMO

PURPOSE: This study aimed to investigate three-dimensional facial soft tissue dimensions, maximum bite force (MBF), and occlusal contact area in patients with DFD. In addition, we analyzed the relationship between MBF and the three-dimensional facial measurements. METHODS: Thirty-two patients with skeletal Class III DFD and 20 patients with Class II DFD underwent a soft tissue evaluation using surface laser scanning, as well as MBF and occlusal contact area assessments. The DFD groups were compared with each other and with 25 healthy subjects. RESULTS: Significant morphological differences were found in the transversal, vertical, and anteroposterior dimensions between Class II DFD and Class III DFD. Both DFD groups presented an increased linear distance of chin height, which was strongly related with decreased MBF magnitude. The DFD groups exhibited lower MBF and occlusal contact area, with no significant differences between Class II and Class III DFD. CONCLUSION: The presence of DFD affected 3D measurements of facial soft tissue, causing variations beyond normal limits, lower MBF, and occlusal contact area in both Class II and Class III DFD patients. The vertical dimension might have influenced the lower MBF magnitude in the studied skeletal deformities.


Assuntos
Força de Mordida , Cefalometria , Face , Imageamento Tridimensional , Humanos , Feminino , Masculino , Face/fisiopatologia , Face/diagnóstico por imagem , Adulto Jovem , Adulto , Estudos de Casos e Controles , Adolescente , Má Oclusão Classe III de Angle/fisiopatologia , Má Oclusão Classe III de Angle/diagnóstico por imagem , Má Oclusão Classe II de Angle/fisiopatologia , Má Oclusão Classe II de Angle/diagnóstico por imagem , Estudos Transversais
3.
J Exp Biol ; 227(9)2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38726757

RESUMO

Differences in the physical and behavioral attributes of prey are likely to impose disparate demands of force and speed on the jaws of a predator. Because of biomechanical trade-offs between force and speed, this presents an interesting conundrum for predators of diverse prey types. Loggerhead shrikes (Lanius ludovicianus) are medium-sized (∼50 g) passeriform birds that dispatch and feed on a variety of arthropod and vertebrate prey, primarily using their beaks. We used high-speed video of shrikes biting a force transducer in lateral view to obtain corresponding measurements of bite force, upper and lower bill linear and angular displacements, and velocities. Our results show that upper bill depression (about the craniofacial hinge) is more highly correlated with bite force, whereas lower bill elevation is more highly correlated with jaw-closing velocity. These results suggest that the upper and lower jaws might play different roles for generating force and speed (respectively) in these and perhaps other birds as well. We hypothesize that a division of labor between the jaws may allow shrikes to capitalize on elements of force and speed without compromising performance. As expected on theoretical grounds, bite force trades-off against jaw-closing velocity during the act of biting, although peak bite force and jaw-closing velocity across individual shrikes show no clear signs of a force-velocity trade-off. As a result, shrikes appear to bite with jaw-closing velocities and forces that maximize biting power, which may be selectively advantageous for predators of diverse prey that require both jaw-closing force and speed.


Assuntos
Força de Mordida , Arcada Osseodentária , Animais , Fenômenos Biomecânicos , Arcada Osseodentária/fisiologia , Passeriformes/fisiologia , Comportamento Predatório/fisiologia , Bico/fisiologia , Gravação em Vídeo
4.
Anat Histol Embryol ; 53(3): e13050, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38706182

RESUMO

Dogs are animals with strong bite force. This strong bite mechanism has led to significant changes in the skeletal system such as fossa masseterica. It can be thought that one side is used more than the other side in chewing and is related to the preference of using the same side's hand, eye and foot. In the study, directional asymmetry and fluctuating asymmetry, which occurs as a result of chewing asymmetry, were examined on the first molar teeth and the fossa masseterica in 85 dog mandibles including a wide diversity of morphotypes. The association of high PC1 values for directional asymmetry with a pronounced cranial index, as evident in breeds like Pekingese, Pomeranian and Bulldog, indicates a potential evolutionary or selective breeding trend favouring brachycephaly. On the contrary, guardian breeds like the German shepherd and Bernese mountain dog, which typically require strong jaws for their roles, showcased reduced PC1 values, which might be related to their functional morphology. Similarly, the PCA results for the first molar teeth shape variations also highlighted the influence of cranial shape, with boxer dogs displaying notably higher PC1 values. The fluctuating asymmetrical distributions provided valuable insights into individualistic variations. Interestingly, no specific breed distribution trend was observed for these asymmetries, indicating a more individual-based variation rather than breed-based. It is essential to note that while these results provide valuable insights, further studies are required to understand the underlying causes better. Factors like genetic variations, developmental processes, dietary habits and external environmental factors could play pivotal roles in these observed morphological differences.


Assuntos
Mastigação , Dente Molar , Animais , Cães/anatomia & histologia , Cães/fisiologia , Dente Molar/anatomia & histologia , Dente Molar/fisiologia , Mastigação/fisiologia , Masculino , Feminino , Mandíbula/anatomia & histologia , Força de Mordida
5.
J Morphol ; 285(5): e21699, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38715161

RESUMO

In 1974, Sue Herring described the relationship between two important performance variables in the feeding system, bite force and gape. These variables are inversely related, such that, without specific muscular adaptations, most animals cannot produce high bite forces at large gapes for a given sized muscle. Despite the importance of these variables for feeding biomechanics and functional ecology, the paucity of in vivo bite force data in primates has led to bite forces largely being estimated through ex vivo methods. Here, we quantify and compare in vivo bite forces and gapes with output from simulated musculoskeletal models in two craniofacially distinct strepsirrhines: Eulemur, which has a shorter jaw and slower chewing cycle durations relative to jaw length and body mass compared to Varecia. Bite forces were collected across a range of linear gapes from 16 adult lemurs (suborder Strepsirrhini) at the Duke Lemur Center in Durham, North Carolina representing three species: Eulemur flavifrons (n = 6; 3F, 3M), Varecia variegata (n = 5; 3F, 2M), and Varecia rubra (n = 5; 5F). Maximum linear and angular gapes were significantly higher for Varecia compared to Eulemur (p = .01) but there were no significant differences in recorded maximum in vivo bite forces (p = .88). Simulated muscle models using architectural data for these taxa suggest this approach is an accurate method of estimating bite force-gape tradeoffs in addition to variables such as fiber length, fiber operating range, and gapes associated with maximum force. Our in vivo and modeling data suggest Varecia has reduced bite force capacities in favor of absolutely wider gapes compared to Eulemur in relation to their longer jaws. Importantly, our comparisons validate the simulated muscle approach for estimating bite force as a function of gape in extant and fossil primates.


Assuntos
Força de Mordida , Animais , Fenômenos Biomecânicos , Arcada Osseodentária/anatomia & histologia , Arcada Osseodentária/fisiologia , Lemur/fisiologia , Lemur/anatomia & histologia , Mastigação/fisiologia , Masculino , Feminino
6.
Nat Commun ; 15(1): 3275, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38627430

RESUMO

Functional trade-offs can affect patterns of morphological and ecological evolution as well as the magnitude of morphological changes through evolutionary time. Using morpho-functional landscape modelling on the cranium of 132 carnivore species, we focused on the macroevolutionary effects of the trade-off between bite force and bite velocity. Here, we show that rates of evolution in form (morphology) are decoupled from rates of evolution in function. Further, we found theoretical morphologies optimising for velocity to be more diverse, while a much smaller phenotypic space was occupied by shapes optimising force. This pattern of differential representation of different functions in theoretical morphological space was highly correlated with patterns of actual morphological disparity. We hypothesise that many-to-one mapping of cranium shape on function may prevent the detection of direct relationships between form and function. As comparatively only few morphologies optimise bite force, species optimising this function may be less abundant because they are less likely to evolve. This, in turn, may explain why certain clades are less variable than others. Given the ubiquity of functional trade-offs in biological systems, these patterns may be general and may help to explain the unevenness of morphological and functional diversity across the tree of life.


Assuntos
Evolução Biológica , Crânio , Crânio/anatomia & histologia , Força de Mordida , Filogenia
7.
Comput Methods Programs Biomed ; 250: 108174, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38640839

RESUMO

STATEMENT OF PROBLEM: Advanced cases of head and neck cancer involving the mandible often require surgical removal of diseased sections and subsequent replacement with donor bone. During the procedure, the surgeon must make decisions regarding which bones or tissues to resect. This requires balancing tradeoffs related to issues such as surgical access and post-operative function; however, the latter is often difficult to predict, especially given that long-term functionality also depends on the impact of post-operative rehabilitation programs. PURPOSE: To assist in surgical decision-making, we present an approach for estimating the effects of reconstruction on key aspects of post-operative mandible function. MATERIAL AND METHODS: We develop dynamic biomechanical models of the reconstructed mandible considering different defect types and validate them using literature data. We use these models to estimate the degree of functionality that might be achieved following post-operative rehabilitation. RESULTS: We find significant potential for restoring mandibular functionality, even in cases involving large defects. This entails an average trajectory error below 2 mm, bite force comparable to a healthy individual, improved condyle mobility, and a muscle activation change capped at a maximum of 20%. CONCLUSION: These results suggest significant potential for adaptability in the masticatory system and improved post-operative rehabilitation, leading to greater restoration of jaw function.


Assuntos
Simulação por Computador , Mandíbula , Reconstrução Mandibular , Mastigação , Humanos , Reconstrução Mandibular/métodos , Mandíbula/cirurgia , Fenômenos Biomecânicos , Força de Mordida
8.
J Neuromuscul Dis ; 11(3): 655-664, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38517801

RESUMO

Background: Hereditary proximal spinal muscular atrophy (SMA) is characterized by abnormal alpha motor neuron function in brainstem and spinal cord. Bulbar dysfunction, including limited mouth opening, is present in the majority of patients with SMA but it is unknown if and how these problems change during disease course. Objective: In this prospective, observational, longitudinal natural history study we aimed to study bulbar dysfunction in patients with SMA types 2 and 3. Methods: We included 44 patients with SMA types 2 and 3 (mean age was 33.6 (95% CI 28.4;38.9) and re-examined them after on average 4 years. None were treated with SMN-modulating treatments before or during the course of this study. Longitudinal assessments included a questionnaire on mandibular and bulbar function, the Mandibular Function Impairment Questionnaire (MFIQ), and a clinical examination of masticatory performance, maximum voluntary bite force, and mandibular movements including the active maximal mouth opening. Results: We found significant higher MFIQ scores and a significant decrease of all mandibular movements in patients with SMA type 2 (p < 0.001), but not in SMA type 3. Masticatory performance and maximum voluntary bite force did not change significantly. Mean reduction of active maximal mouth opening at follow-up was 3.5 mm in SMA type 2 (95% CI: 2.3; 4.7, p < 0.001). SMA type 2 was an independent predictor for a more severe reduction of the mouth opening (ß= -2.0 mm (95% CI: -3.8; -0.1, p = 0.043)). Conclusions: Bulbar functions such as mandibular mobility and active maximum mouth opening decrease significantly over the course of four years in patients with SMA type 2.


Assuntos
Mandíbula , Atrofias Musculares Espinais da Infância , Humanos , Masculino , Feminino , Adulto , Estudos Prospectivos , Estudos Longitudinais , Atrofias Musculares Espinais da Infância/fisiopatologia , Mandíbula/fisiopatologia , Adulto Jovem , Adolescente , Força de Mordida , Pessoa de Meia-Idade , Mastigação/fisiologia , Progressão da Doença
9.
BMC Oral Health ; 24(1): 350, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38504207

RESUMO

BACKGROUND: Clear aligner therapy has gained popularity as a minimally invasive orthodontic treatment option. However, its impact on the masticatory musculature and the stomatognathic system is an area of growing interest, as it involves the adjustment of occlusion and tooth movement. This systematic review aims to comprehensively assess and synthesise existing evidence regarding the influence of clear aligner therapy on the masticatory musculature and the stomatognathic system. METHODS: An exhaustive search was performed on electronic databases that adhered to PRISMA guidelines. Clinical studies that evaluated the impact of patients receiving aligner orthodontic treatment on the muscles of the mastication and stomatognathic systems were included. A standardised data extraction form was devised for relevant variables. Two reviewers extracted the data variables. ROB-2 was used for bias evaluation in the selected studies. RESULTS: A total of six studies met the inclusion criteria. The wearing of clear aligners significantly impacted the muscles of mastication. Muscle activity and discomfort showed a significant alteration in the initial days of appliance placement. but this observation was temporary, with no significant changes thereafter in subsequent follow-up. Bite force reduction was also noted. All the studies evaluated showed good methodological quality. CONCLUSION: The review found that aligned orthodontic treatment may have a variable impact on muscles of mastication, with a potential for initial exacerbation of symptoms followed by possible improvement. However, due to the limited number of studies and their heterogeneous nature, further robust research is recommended to fully understand the relationship between aligned orthodontic treatment and masticatory muscles.


Assuntos
Músculos da Mastigação , Aparelhos Ortodônticos Removíveis , Humanos , Sistema Estomatognático , Oclusão Dentária , Força de Mordida
10.
PLoS One ; 19(3): e0300157, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38483856

RESUMO

OBJECTIVE: The current body of research on utilizing botulinum toxin (BTX) to manage temporomandibular disorders (TMDs) has not yet yielded definitive conclusions. The primary objective of this study was to determine the effectiveness of BTX in pain reduction for TMDs compared to placebo and other treatments. The secondary outcomes evaluated were adverse events, maximum mouth opening, bruxism events, and maximum occlusal force. MATERIALS AND METHODS: A literature search was performed on PubMed, Dimension Publication, Scopus, and Google Scholar. The RoB 2 tool was used for quality assessment. The mean differences in pain scores were estimated to measure the effect of BTX on pain reduction. For adverse events, the risk ratio for the incidence of side effects was calculated. RESULTS: Two hundred and sixty non-duplicate articles were identified; however, only 14 RCTS were included in this review. The total study population included 395 patients. The overall risk of bias showed a low to moderate quality of evidence. Results from 6 studies were reported only narratively; four studies were used for meta-analysis on pain reduction, and five were used for meta-analysis on adverse events. The control used in the meta-analysis was placebo injections. Results of the meta-analysis for pain reduction were statistically insignificant for the BTX group with mean differences at MD = -1.71 (95% CI, -2.87 to -0.5) at one month, -1.53 (95% CI, -2.80 to -0.27) at three months, and -1.33 (95% CI, -2.74 to 0.77) at six months. This showed that BTX treatment was not significantly better than placebo for a reduction in pain scores at 1, 3, and 6 months. Regarding safety, the placebo group showed a relative risk of 1.34 (95%CI, 0.48-6.78) and 1.17 (95%CI, 0.54-3.88) at 1 and 3 months respectively. However, the risks were not statistically significant. There was also no difference in the effectiveness of BTX compared to placebo and other treatments for maximum mouth opening, bruxism events, and maximum occlusal force. CONCLUSION: BTX was not associated with better outcomes in terms of pain reduction, adverse events, maximum mouth opening, bruxism events, and maximum occlusal force. More high-quality RCTs are needed to better understand this topic.


Assuntos
Toxinas Botulínicas Tipo A , Bruxismo , Transtornos da Articulação Temporomandibular , Humanos , Toxinas Botulínicas Tipo A/efeitos adversos , Bruxismo/tratamento farmacológico , Dor/tratamento farmacológico , Transtornos da Articulação Temporomandibular/tratamento farmacológico , Força de Mordida
11.
Clin Oral Investig ; 28(3): 197, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38448748

RESUMO

OBJECTIVES: This study aimed to investigate the strain in the bone surrounding dental implants supporting a 4-unit bridge and assess the role of excessive strain as a possible risk factor for implant related sequestration (IRS) or peri-implant medication-related osteonecrosis of the jaw (PI-MRONJ). MATERIALS AND METHODS: A 3D-mandibular model was constructed using computed tomography and segmented it into cortical and cancellous bones. The 4-unit implant-supported bridges replacing the mandibular posteriors were constructed, and each featuring two, three, and four implants, respectively. The Young's modulus was assigned based on the quality of the bone. A maximum occlusal force of 200 N was applied to each implant in the axial and in a 30-degree oblique direction. RESULTS: The maximum principal strain of the fatigue failure range (> 3000 µÎµ) in the bone was analyzed. The volume fraction of fatigue failure was higher in poor-quality bone compared to normal bone and oblique load than in axial load. An increasing number of implants may dissipate excessive strain in poor-quality bones. CONCLUSIONS: Occlusal force applied to poor-quality bone can result in microdamage. Given that unrepaired microdamage may initiate medication-related osteonecrosis of the jaw, long-term occlusal force on fragile bones might be a risk factor. CLINICAL RELEVANCE: When planning implant treatment for patients with compromised bone status, clinical modifications such as strategic placement of implants and optimization of restoration morphology should be considered to reduce excessive strain which might be associated with IRS or PI-MRONJ.


Assuntos
Implantes Dentários , Osteonecrose , Humanos , Força de Mordida , Módulo de Elasticidade , Mandíbula
12.
BMC Oral Health ; 24(1): 307, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38443910

RESUMO

STATEMENT OF PROBLEM: CAD/CAM occlusal veneers have been developed for minimally invasive prosthetic restoration of eroded teeth. Marginal adaptation and fracture resistance are crucial for the long-term survivability and clinical success of such restorations. Virgilite-based lithium disilicate glass-ceramic is a newly introduced material with claims of high strength. However, constructing occlusal veneers from this material of varying thickness has not been investigated. PURPOSE: The current study aimed to assess the impact of CAD/CAM occlusal veneer thickness and materials on marginal adaptation and fracture resistance. MATERIALS AND METHODS: Thirty-two occlusal veneers were constructed and divided into two groups (n = 16) based on the CAD/CAM material into Brilliant Crios and CEREC Tessera. Each group was further subdivided into two subgroups (n = 8) according to the thickness: 0.6 and 0.9 mm. Occlusal veneers were bonded to epoxy resin dies. The marginal gap was evaluated before and after thermodynamic aging. Fracture resistance and failure mode were evaluated for the same samples after aging. Marginal adaptation was analyzed using the Mann-Whitney U test. Fracture resistance was analyzed using Weibull analysis (α = 0.05). RESULTS: The marginal gap was significantly increased following thermodynamic aging for tested groups (P < 0.001). CEREC Tessera showed a significantly higher marginal gap than Brilliant Crios before and after aging for both thicknesses (P < 0.05). CEREC Tessera recorded lower significant fracture load values compared to Brilliant Crios (P < 0.05). CONCLUSIONS: Both CEREC Tessera and Brilliant Crios demonstrated clinically accepted marginal gap values. All groups showed fracture resistance values higher than the average masticatory forces in the premolar region except for 0.6 mm CEREC Tessera. CLINICAL IMPLICATIONS: Reinforced composite occlusal veneers demonstrated more favorable outcomes in terms of marginal gap and fracture resistance at both tested thicknesses compared to virgilite-based lithium disilicate glass-ceramic. Additionally, caution should be exercised during the construction of occlusal veneers from virgilite-based lithium disilicate glass-ceramic with reduced thickness.


Assuntos
Envelhecimento , Força de Mordida , Humanos , Desenho Assistido por Computador , Resinas Epóxi , Estatísticas não Paramétricas
13.
Biol Lett ; 20(3): 20240045, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38531413

RESUMO

In assessments of skeletal variation, allometry (disproportionate change of shape with size) is often corrected to examine size-independent variation for hypotheses relating to function. However, size-related trade-offs in functional demands may themselves be an underestimated driver of mammalian cranial diversity. Here, we use geometric morphometrics alongside dental measurements to assess craniodental allometry in the rock-wallaby genus Petrogale (all 17 species, 370 individuals). We identified functional aspects of evolutionary allometry that can be both extensions of, and correlated negatively with, static or ontogenetic allometric patterns. Regarding constraints, larger species tended to have relatively smaller braincases and more posterior orbits, the former of which might represent a constraint on jaw muscle anatomy. However, they also tended to have more anterior dentition and smaller posterior zygomatic arches, both of which support the hypothesis of relaxed bite force demands and accommodation of different selective pressures that favour facial elongation. By contrast, two dwarf species had stouter crania with divergent dental adaptations that together suggest increased relative bite force capacity. This likely allows them to feed on forage that is mechanically similar to that consumed by larger relatives. Our results highlight a need for nuanced considerations of allometric patterns in future research of mammalian cranial diversity.


Assuntos
Macropodidae , Crânio , Animais , Evolução Biológica , Força de Mordida , Crânio/anatomia & histologia
16.
Int J Prosthodont ; 37(1): 27-33, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38381983

RESUMO

PURPOSE: To determine the influence of partial edentulous distal extension and the use of removable partial dental prostheses in partially edentulous areas on the force exerted on the anterior teeth. MATERIALS AND METHODS: A total of 83 volunteer patients participated in this study. The occlusal force was measured using an occlusal force measuring sheet in the patient's mouth. The occlusal forces and ratios were compared using the Wilcoxon signed-rank test (P < .05). RESULTS: The force exerted on the anterior teeth increased significantly as the number of remaining teeth decreased in an edentulous distal extension. The force exerted on the anterior teeth decreased significantly with the use of a removable partial dental prosthesis. CONCLUSIONS: In a clinical setting, when the number of remaining teeth in a partial edentulous distal extension decreases, the burden on the anterior teeth increases. Our findings suggest that, for patients with partial edentulous distal extension, using a removable partial dental prosthesis is effective in preserving the residual anterior teeth by reducing excessive force.


Assuntos
Prótese Parcial Removível , Arcada Parcialmente Edêntula , Boca Edêntula , Humanos , Face , Força de Mordida
17.
J Dent ; 143: 104887, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38360395

RESUMO

OBJECTIVES: Standardized bite training is required to prevent oral hypofunction in elderly individuals. We aimed to compare masticatory muscle activity between 24 young adults and 16 pre-elderly individuals during a biting task using a novel standardized bite device (BD). METHODS: The BD was made of silicone rubber and included a high-force or low-force plate spring or no plate spring (dummy). The compressive stiffness of the material in each BD was measured using a texture analyzer. All participants performed a biting task 50-times at a rate of 1/s each using the three types of BDs on the right first molar. Electromyographic (EMG) activity was recorded bilaterally from the masseter and temporalis muscles. The variability of each biting training session was calculated as the coefficient of variance (CV) from the EMG activity during each biting task for each muscle. Masticatory muscle fatigue was assessed using a numerical rating scale (NRS). RESULTS: Compressive stiffness was significantly different between each BD (P < 0.001). The CV and NRS scores were not significantly different between the groups. The EMG activities during each bite task in all muscles were not significantly different for any measurement item between the age groups. The EMG activities of high- and low-force BDs in the right temporalis (ipsilateral) muscle were significantly higher than those of the dummy BD (P < 0.001). CONCLUSIONS: Compressive stiffness of the BD affected EMG activity only in the ipsilateral temporalis muscle, but not in the masseter or contralateral temporalis muscles, without any age effect.


Assuntos
Força de Mordida , Músculos da Mastigação , Humanos , Adulto Jovem , Idoso , Músculos da Mastigação/fisiologia , Músculo Masseter/fisiologia , Músculo Temporal/fisiologia , Eletromiografia
18.
BMC Oral Health ; 24(1): 264, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38388920

RESUMO

BACKGROUND: This study aims to analyze the longitudinal variation of occlusal force distribution prior to and after fixed restoration for molar full-crowns with T-SCAN III which provide reference for occlusal adjustment and long-term maintenance. METHODS: We enrolled a total of 20 patients who received conventional restorative treatment for molars. The occlusion examination was conducted in 3 stages (before placement, immediately after placement, and 3 months after placement) using T-SCAN III (Tekscan South Boston, MA, USA, 10.0) to examine and measure the occlusal contact areas of the full dentition. RESULTS: The results indicated that the occlusal force distribution in the molar region of the patients changed before and after the fixed restoration, but the percentages of occlusal force in the dental arch of the molar did not differ significantly before and after the restoration (P > 0.05). Three months after the fixed restoration, the percentage of occlusal force in the restored dental arches of lateral teeth increased significantly (P < 0.05). CONCLUSION: The results of this study indicated that the occlusal forces of the patients changed with tooth movement and adaptation, which is mainly reflected in the increasing occlusal force. Quantitative occlusal force analysis using T-SCAN III occlusal analyzer can provide more objective and accurate data to effectively guide clinical occlusion adjustments.


Assuntos
Força de Mordida , Oclusão Dentária , Humanos , Dente Molar , Coroas , Dentaduras
19.
Int J Clin Pract ; 2024: 6533841, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38420595

RESUMO

Aim: To investigate the impact of the curve of Spee (CS) accentuation on bite force, chewing ability, and additionally, other factors that influence chewing ability and bite force such as restorations, caries, gender, habits, and TMJ problems. Materials and Methods: 231 participants (118 male and 113 female, mean age = ±27.96 years) were recruited for this cross-section study. Participants completed a data collection sheet in which age, gender, Angle's classification of malocclusion, overjet, overbite, TMJ problems, habits, restorations, and caries experience were recorded. Two examiners made a lower impression, chewing ability test and measured the bite force for each participant. Measurement of the CS was obtained digitally from the poured dental cast, and the categorization was as follows: flat (<1 mm), normal (1-2 mm), or deep (>2 mm). Results: The mean maximum bite force (MBF) was 468.722 N for participants with flat CS, 389.822 N for normal CS, 647.08 N for deep CS, and 384.667 N for reverse CS. The average MBF was higher for participants with deep CS (p < 0.05). MBF force was higher in males. However, BMI was not significantly related to MBF values. Participants with normal and flat CS have comparable chewing capacity (p > 0.05). Also, a significant difference in bite force and chewing ability was found between the three categories of CS (p < 0.05). Conclusion: Bite force variations across various CS types were linked to gender and habits. Chewing ability showed no differences concerning gender, habits, TMJ problems, caries, or restorations, emphasizing CS's significant impact on bite force while showcasing the unchanged nature of chewing ability amidst diverse factors.


Assuntos
Força de Mordida , Mastigação , Humanos , Masculino , Feminino , Estudos Transversais
20.
Gen Dent ; 72(2): 60-64, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38411487

RESUMO

This case report presents a challenging case of catastrophic failure of a fixed partial denture involving fracture of the prosthesis as well as supporting implants and teeth. The use of robotics facilitated efficient and successful restoration of the patient's dentition. After extraction of 2 fractured teeth and 1 fractured implant, 2 new implants were placed with haptic guidance from robotics, which allowed for stable osteotomies and high initial implant stability quotients. Due to the patient's tremors and heavy occlusal forces, restoration was delayed to allow the surgical site to heal, and the patient received a provisional partial denture. With subsequent placement of the final restoration, the treatment was fully completed in 4.5 months and required only a single surgical procedure. The use of haptic robotics in this case allowed for accurate planning, spacing, and placement of screw-retained implants with an optimal arch, leading to the best long-term outcome for the patient.


Assuntos
Implantes Dentários , Robótica , Fraturas dos Dentes , Humanos , Força de Mordida , Parafusos Ósseos
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