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International Journal of Surgery Case... Jun 2024Aliments such as congenital conditions, pathological, and iatrogenic circumstances may result in mandibular defects that can severely disturb the patients' oral health,...
INTRODUCTION AND IMPORTANCE
Aliments such as congenital conditions, pathological, and iatrogenic circumstances may result in mandibular defects that can severely disturb the patients' oral health, functions (mastication, speech), aesthetics, and quality of life and present a rehabilitating challenge.
CASE PRESENTATION
we present a multidisciplinary treatment approach for three cases presented with mandibular resection as a consequence of cystic, benign, and malignant tumour eradication that were rehabilitated with immediately loaded fixed corticobasal implant-supported prostheses and a follow-up period of 5,5 and 4 years. The reported cases present with excellent implant survival, along with healthy peri-implant tissues, stable prostheses, enhanced speech, chewing ability, aesthetics, superior patient satisfaction, and improved overall self-esteem.
CLINICAL DISCUSSION
A multidisciplinary oral and maxillofacial team is mandatory for the successful rehabilitation of patients with mandibular resection and to restore soft and hard tissue loss. The reported treatment modality offers the patient immediate fixed implant-supported prostheses omitting the need for a bone grafting procedure, with optimum peri-implant tissue health, excellent biomechanical and prosthetic results, and significant improvement in function and satisfaction.
CONCLUSION
Corticobasal fixed implant-supported prostheses can be a reliable treatment modality for mandibular resection, resulting in notable enhancements in the patients' oral health, appearance, mastication, speech, and self-esteem.
PubMed: 38677251
DOI: 10.1016/j.ijscr.2024.109707 -
Nutrients Apr 2024Given the changes in the digestive tract post-bariatric surgery, adapting to a new pattern of eating behavior becomes crucial, with special attention to the specifics of...
Given the changes in the digestive tract post-bariatric surgery, adapting to a new pattern of eating behavior becomes crucial, with special attention to the specifics of chewing mechanics. This study aimed to investigate the association between self-perception of chewing, chewing behavior, and the presence of gastrointestinal symptoms in preoperative patients undergoing bariatric surgery. Sixty adult candidates for bariatric surgery at a public hospital in Belém (Brazil) were analyzed. Participants predominantly exhibited unilateral chewing patterns (91.6%), a fast chewing rhythm (73.3%), a large food bolus (80%), liquid intake during meals (36.7%), and 41.7% reported that chewing could cause some issue. Significant associations were found between the perception of causing problems and chewing scarcity ( = 0.006), diarrhea ( = 0.004), absence of slow chewing ( = 0.048), and frequent cutting of food with front teeth ( = 0.034). These findings reveal a relationship between the perception of chewing problems and chewing scarcity, presence of diarrhea, and fast chewing.
Topics: Humans; Mastication; Bariatric Surgery; Female; Male; Adult; Middle Aged; Self Concept; Feeding Behavior; Gastrointestinal Diseases; Diarrhea; Brazil; Cross-Sectional Studies; Obesity, Morbid
PubMed: 38674787
DOI: 10.3390/nu16081096 -
International Journal of Molecular... Apr 2024This review deals with the developmental origins of extraocular, jaw and laryngeal muscles, the expression, regulation and functional significance of sarcomeric myosin... (Review)
Review
This review deals with the developmental origins of extraocular, jaw and laryngeal muscles, the expression, regulation and functional significance of sarcomeric myosin heavy chains (MyHCs) that they express and changes in MyHC expression during phylogeny. Myogenic progenitors from the mesoderm in the prechordal plate and branchial arches specify craniofacial muscle allotypes with different repertoires for MyHC expression. To cope with very complex eye movements, extraocular muscles (EOMs) express 11 MyHCs, ranging from the superfast extraocular MyHC to the slowest, non-muscle MyHC IIB (nmMyH IIB). They have distinct global and orbital layers, singly- and multiply-innervated fibres, longitudinal MyHC variations, and palisade endings that mediate axon reflexes. Jaw-closing muscles express the high-force masticatory MyHC and cardiac or limb MyHCs depending on the appropriateness for the acquisition and mastication of food. Laryngeal muscles express extraocular and limb muscle MyHCs but shift toward expressing slower MyHCs in large animals. During postnatal development, MyHC expression of craniofacial muscles is subject to neural and hormonal modulation. The primary and secondary myotubes of developing EOMs are postulated to induce, via different retrogradely transported neurotrophins, the rich diversity of neural impulse patterns that regulate the specific MyHCs that they express. Thyroid hormone shifts MyHC 2A toward 2B in jaw muscles, laryngeal muscles and possibly extraocular muscles. This review highlights the fact that the pattern of myosin expression in mammalian craniofacial muscles is principally influenced by the complex interplay of cell lineages, neural impulse patterns, thyroid and other hormones, functional demands and body mass. In these respects, craniofacial muscles are similar to limb muscles, but they differ radically in the types of cell lineage and the nature of their functional demands.
Topics: Animals; Humans; Facial Muscles; Gene Expression Regulation, Developmental; Muscle Development; Myosin Heavy Chains; Oculomotor Muscles; Phylogeny
PubMed: 38674131
DOI: 10.3390/ijms25084546 -
Bioengineering (Basel, Switzerland) Mar 2024The purposes of this study are to establish and validate a finite element (FE) model using finite element analysis methods and to identify optimal loading conditions to...
The purposes of this study are to establish and validate a finite element (FE) model using finite element analysis methods and to identify optimal loading conditions to simulate masticatory movement. A three-dimensional FE model of the maxillary and mandibular cortical bone, cancellous bone, and gingiva was constructed based on edentulous cone-beam-computed tomography data. Dental computer-aided design software was used to design the denture base and artificial teeth to produce a complete denture. Mesh convergence was performed to derive the optimal mesh size, and validation was conducted through comparison with mechanical test results. The mandible was rotated step-by-step to induce movements similar to actual mastication. Results showed that there was less than a 6% difference between the mechanical test and the alveolar bone-complete denture. It opened 10° as set in the first stage, confirming that the mouth closed 7° in the second stage. Occlusal contact occurred between the upper and lower artificial teeth as the mouth closed the remaining angle of 3° in the third stage while activating the masseter muscle. These results indicate that the FE model and masticatory loading conditions developed in this study can be applied to analyze biomechanical effects according to the wearing of dentures with various design elements applied.
PubMed: 38671758
DOI: 10.3390/bioengineering11040336 -
The Journal of Prosthetic Dentistry Jun 2024More data are needed on the influence of preparation design on the fracture strength, failure type, repairability, and polymerization-induced cracks of molar teeth...
STATEMENT OF PROBLEM
More data are needed on the influence of preparation design on the fracture strength, failure type, repairability, and polymerization-induced cracks of molar teeth restored with direct composite resin restorations.
PURPOSE
This in vitro and finite element analysis study investigated the effect of different preparation designs on fracture strength, failure type, repairability, tooth deformation, and the formation of polymerization-induced cracks of compromised molars restored with direct composite resin restorations.
MATERIAL AND METHODS
Human molars (n=64) were randomly assigned to 4 different preparation designs: undermined inlay (UI), extended inlay (EI), restricted overlay (RO), and extended overlay (EO). The teeth were restored using direct composite resin and subjected to artificial thermomechanical aging in a mastication simulator, followed by load-to-failure testing. Three-dimensional (3D) finite element analysis was conducted to assess tooth deformation. Polymerization-induced cracks were evaluated using optical microscopy and transillumination. The fracture strength data were analyzed using a Kruskal-Wallis test, while the failure mode, repairability, and polymerization cracks were analyzed using the Fisher exact test (α=.05).
RESULTS
All specimens withstood thermomechanical aging, and no statistically significant difference in fracture strength was observed among the 4 preparation designs (P>.05). The finite element analysis showed differences in tooth deformation, but no correlation was observed with in vitro fracture resistance. The RO and EO groups presented significantly more destructive failures compared with the UI and EI groups (P<.01). The RO group had significantly fewer repairable failures than the UI and EI groups (P=.024). A correlation was found between higher frequencies of repairability and higher tooth deformation. A significant correlation between the increase in microfractures and preparation design was observed (P<.01), with the UI group exhibiting a higher increase in microfracture size compared with the EO group (P<.05).
CONCLUSIONS
No influence of preparation design on the fracture strength of compromised molars restored with direct composite resin restorations was evident in this study, but the failure mode of cusp coverage restorations was more destructive and often less repairable. The finite element analysis showed more tooth deformation in inlay preparations, with lower stresses within the root, leading to more reparable fractures. Since cusp coverage direct composite resin restorations fractured in a more destructive manner, this study suggests that even a tooth with undermined cusps should be restored without cusp coverage.
Topics: Composite Resins; Finite Element Analysis; Humans; Molar; Dental Restoration Failure; Dental Restoration, Permanent; Dental Stress Analysis; Tooth Fractures; In Vitro Techniques; Inlays; Materials Testing; Polymerization
PubMed: 38670907
DOI: 10.1016/j.prosdent.2024.03.039 -
MethodsX Jun 2024In the literature, there is consistent evidence related to the influence of chewing on brain functions, either from experimental models or in humans. In the case of...
In the literature, there is consistent evidence related to the influence of chewing on brain functions, either from experimental models or in humans. In the case of humans, most results are restricted to functional tests, lacking cellular or molecular evidence. In the described method, the possibility of using experimental models is presented, as well as the mimicry of deprivation and rehabilitation of masticatory activity and without stress impact. By opting for the use of mash feed, instead of extracting or implanting an intraoral device, alternations between restriction and rehabilitation of mastication were imposed on murine models. The animals completed various temporal windows, with aging also representing a potential factor for translational dementia associations. Additionally, animals were segregated into environments characterized as either standard, simulating a sedentary lifestyle, or enriched, rich in sensorimotor and visuospatial stimulation. Thus, it was possible to study the influence of changes in masticatory activity, associated with aging and environmental enrichment, on cells from subregions of the hippocampus, as well as on performance in tests of learning and spatial memory.•Animal model for masticatory activity alteration;•Masticatory deprivation and rehabilitation, and•Models to study the interaction among masticatory activity, aging and enrichment environment.
PubMed: 38660048
DOI: 10.1016/j.mex.2024.102701 -
Cureus Mar 2024Facial muscles, particularly those involved in mastication, play a pivotal role in the chewing process. Despite their influence on chewing, these muscles undergo...
BACKGROUND
Facial muscles, particularly those involved in mastication, play a pivotal role in the chewing process. Despite their influence on chewing, these muscles undergo alterations during mastication. Examining the relationship between chewed substances and muscle activity can provide insights into various pathological processes and aid in the development of therapeutic chewing techniques.
AIM
This study aimed to evaluate the impact of different commercially available chewing gums on the activity of key masticatory muscles.
METHOD
Twenty-two participants were recruited for the study. They were instructed to chew four commercially available gums: group 1 comprised sugar gum with a strong flavor; group 2 included gum containing sorbitol; group 3 consisted of gum containing xylitol; and group 4 provided sugar gum with a mild flavor. Electromyogram (EMG) recordings were utilized to assess muscle activity. Various aspects of muscle activity, including chewing time, maximum muscle potential, and coordination between different muscles, were evaluated. Data tabulation and analysis were performed using IBM SPSS software version 23.0 (IBM Corp., Armonk, NY).
RESULT
Analysis revealed that in terms of temporalis symmetry, group 2 exhibited the highest mean deviation, while for masseter symmetry, group 3 demonstrated the highest mean deviation. The total deviation for the temporalis and masseter muscles was 72.16% and 65.55%, respectively, indicating greater symmetry in the temporalis muscle. Additionally, group 3 displayed the highest mean deviation in both left and right-sided synergic activity of the muscles. The total deviation for the right and left sides was 64.34% and 65.67%, respectively.
CONCLUSION
The findings suggest that sugar-free chewing gums elicit increased muscle activity compared to sugar-containing chewing gums. Furthermore, the utilization of calorie-free chewing gums with a firm texture was associated with better-coordinated muscle activity. These results provide valuable insights into the effects of different chewing gums on masticatory muscle function and coordination, which may have implications for therapeutic interventions and oral health management.
PubMed: 38659520
DOI: 10.7759/cureus.56849 -
BMC Oral Health Apr 2024Up to 25% of the tooth extraction after root canal treatment could be attributed to the vertical root fracture (VRF). The treatment choice for teeth with VRF would...
BACKGROUND
Up to 25% of the tooth extraction after root canal treatment could be attributed to the vertical root fracture (VRF). The treatment choice for teeth with VRF would mostly be the extraction despite some repairing methods were also reported. The repairing treatment result of VRF would mostly depend on the fixation strength and the bioactivity of the repairing materials, especially for the posterior teeth with high masticating stresses. This case report designed a novel surgical treatment approach for the VRF of posterior teeth.
METHODS
a maxillary premolar with buccal-palatal complete VRF was treated with a new dual-layered repairing approach using adhesive resin + iRoot BP Plus bioceramic cement to fill the modified fracture line with retention forms through the intentional replantation.
RESULTS
At the 24-month review, the tooth showed desirable periodontal healing and normal function.
CONCLUSIONS
This case report indicated that the dual-layered repairing approach might be effective for saving the posterior teeth with VRF. Nevertheless, further clinical trials are needed for its long-term result.
Topics: Humans; Tooth Fractures; Tooth Root; Bicuspid; Male; Female; Tooth Replantation; Root Canal Therapy
PubMed: 38658927
DOI: 10.1186/s12903-024-04268-9 -
Ecology and Evolution Apr 2024Morphological adaptation is the change in the form of an organism that benefits the individual in its current habitat. Mole-rats (family Bathyergidae), despite being...
Morphological adaptation is the change in the form of an organism that benefits the individual in its current habitat. Mole-rats (family Bathyergidae), despite being subterranean, are impacted by both local and broad-scale environmental conditions that occur above ground. Common mole-rats () present an ideal mammalian model system for the study of morphological variation in response to ecology, as this species is found along an aridity gradient and thus can be sampled from geographically non-overlapping populations of the same species along an environmental longitudinal cline. Using the mass of five internal organs, ten skeletal measurements and 3D morphometric analyses of skulls, we assessed the morphology of wild non-breeding individuals from five common mole-rat populations in South Africa. We found that the body mass and mean relative mass of the spleen and kidneys in arid populations was larger, and individuals from arid regions possessed shorter legs and larger inter-shoulder widths compared to individuals from mesic regions. Additionally, arid populations demonstrated greater skull depth, and shape change of features such as angular processes of the lower jaw than mesic individuals, indicating that these distinct geographic populations show differences corresponding to the aridity gradient, potentially in response to environmental factors such as the variation in food sources found between different habitats, in addition to different soil compositions found in the different regions. Arid populations potentially require a stronger jaw and neck musculature associated with mastication to chew xeric-adapted plants and to dig through hard soil types, whereas mesic populations excavate through soft, looser soil and may make use of their front limbs to aid the movement of soils when digging. Aridity influences the morphology of this species and could indicate the impact of environmental changes on speciation and mammalian skull morphology.
PubMed: 38651162
DOI: 10.1002/ece3.11301 -
Computer Methods and Programs in... Jun 2024Advanced cases of head and neck cancer involving the mandible often require surgical removal of diseased sections and subsequent replacement with donor bone. During the...
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.
Topics: Humans; Mastication; Mandibular Reconstruction; Mandible; Computer Simulation; Biomechanical Phenomena; Bite Force
PubMed: 38640839
DOI: 10.1016/j.cmpb.2024.108174