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Clinical, Cosmetic and Investigational... 2024Endodontically treated teeth (ETT) undergo extensive structure change and experience high stress during biomechanical function. Stress distribution is influenced by the...
INTRODUCTION
Endodontically treated teeth (ETT) undergo extensive structure change and experience high stress during biomechanical function. Stress distribution is influenced by the restoration material and the type of bond between material and tooth structure. The selection of materials that can distribute stress will affect the resistance and retention of ETT to mastication forces, thus biomechanical functions were achieved. Composite has mechanical properties similar to dentin, it can transmit and distribute stresses throughout the tooth surface. The disadvantage of composites in large cavities is their lack of toughness. The addition of fiber to composites can increase their toughness.
PURPOSE
This research is to determine the stress distribution of a fiber-reinforced composite made of polyethylene and e-glass on the mesiolingual cavity of ETT.
MATERIALS AND METHODS
A three-dimensional model of the mandibular molar was prepared for cavity preparation and the formation of restorations using SolidWorks 2021. The models were analyzed with Abaqus 2020 to determine stress concentrations after given vertical and oblique loading.
RESULTS
The maximum and minimum principal stress data were obtained to assess material resistance and interfacial damage criterion. Polyethylene fiber shows a more homogeneous stress distribution because the modulus of elasticity is close to the dentin and has a thickness that can reduce the volume of the composite. The E-glass shows the stress concentration on the circumferential fiber and cavity floor.
CONCLUSION
The stress distribution of fiber-reinforced composite on the buccolingual cavity of ETT using the finite element method did not show structural failure in the polyethylene group because the maximum and minimum principal stresses were lower than the strength of the material. Interfacial bond failure occurs at the enamel portion. The maximum and minimum principal values of e-glass indicate structural failure in the circumferential fiber and the base fiber because the stress exceeds the strength of the material. Interfacial bond failure occurred on the circumferential and the cavity floor.
PubMed: 38632981
DOI: 10.2147/CCIDE.S450325 -
BMC Oral Health Apr 2024This cross-sectional study aimed to identify factors associated with age-related changes in masticatory performance (MP) and oral diadochokinesis (ODK) and to provide...
BACKGROUND
This cross-sectional study aimed to identify factors associated with age-related changes in masticatory performance (MP) and oral diadochokinesis (ODK) and to provide normal values in healthy old adults for the diagnosis of oral frailty.
METHODS
A total of 385 participants were divided into three age groups (Gr1-3): 20-64 years, 65-74 years, and ≥ 75 years. To investigate tongue-lip motor function, ODK was assessed as the number of repetitions of the monosyllables /pa/ta/ka/. Four questionnaires were used to assess subjective masticatory ability, cognitive ability, and psychological status. MP, bite force, and occlusal area were tested to assess dynamic objective masticatory function, and the number of remaining teeth and functional tooth pairs were determined to assess static objective masticatory function. Handgrip strength (HG), oral dryness, and tongue pressure (TP) were assessed to identify influencing factors. Intergroup differences were evaluated by ANOVA and the Kruskal‒Wallis test, and correlations between ODK and orofacial factors were evaluated.
RESULTS
This study revealed significant age-related declines in TP, HG, and ODK, especially after 65 years of age. Factors affecting MP were posterior teeth, the Eichner index, bite force, occluding area, the Korean Mini-Mental State Examination (KMMSE) score, and ODK. Each ODK syllable was associated with different factors, but common factors associated with ODK were MP, HG, and PHQ-9 score. For the syllables /pa/ta/, the Eichner Index, TP, and oral dryness were also associated. For the syllable /ka/ in Gr3, MP, TP, HG, oral dryness, and the KMMSE score were associated.
CONCLUSIONS
These results could provide practical guidelines for oral rehabilitation in old adults and contribute to improving the understanding of age-related changes in oral function and the multidimensional nature of masticatory dynamics.
Topics: Adult; Humans; Aged; Tongue; Hand Strength; Cross-Sectional Studies; Pressure; Mastication; Xerostomia
PubMed: 38627762
DOI: 10.1186/s12903-024-04214-9 -
Experimental & Applied Acarology May 2024Changes in the functional shape of astigmatan mite moveable digit profiles are examined to test if Tyrophagus putrescentiae (Acaridae) is a trophic intermediate between...
Changes in the functional shape of astigmatan mite moveable digit profiles are examined to test if Tyrophagus putrescentiae (Acaridae) is a trophic intermediate between a typical micro-saprophagous carpoglyphid (Carpoglyphus lactis) and a common macro-saprophagous glycyphagid (Glycyphagus domesticus). Digit tip elongation in these mites is decoupled from the basic physics of optimising moveable digit inertia. Investment in the basal ramus/coronoid process compared to that for the moveable digit mastication length varies with feeding style. A differentiated ascending ramus is indicated in C. lactis and in T. putrescentiae for different trophic reasons. Culturing affects relative investments in C. lactis. A markedly different style of feeding is inferred for the carpoglyphid. The micro-saprophagous acarid does not have an intermediate pattern of trophic functional form between the other two species. Mastication surface shape complexity confirms the acarid to be heterodontous. T. putrescentiae is a particularly variably formed species trophically. A plausible evolutionary path for the gradation of forms is illustrated. Digit form and strengthening to resist bending under occlusive loads is explored in detail. Extensions to the analytical approach are suggested to confirm the decoupling of moveable digit pattern from cheliceral and chelal adaptations. Caution is expressed when interpreting ordinations of multidimensional data in mites.
Topics: Animals; Acaridae; Extremities; Biomechanical Phenomena; Feeding Behavior; Mastication; Female
PubMed: 38622432
DOI: 10.1007/s10493-024-00907-6 -
Zhong Nan Da Xue Xue Bao. Yi Xue Ban =... Jan 2024Trigeminal neuralgia is a manifestation of orofacial neuropathic pain disorder, always deemed to be an insurmountable peak in the field of pain research and treatment....
Trigeminal neuralgia is a manifestation of orofacial neuropathic pain disorder, always deemed to be an insurmountable peak in the field of pain research and treatment. The pain is recurrent, abrupt in onset and termination similar to an electric shock or described as shooting. A poor quality of life has been attributed to trigeminal neuralgia, as the paroxysms of pain may be triggered by innocuous stimuli on the face or inside the oral cavity, such as talking, washing face, chewing and brushing teeth in daily life. The pathogenesis of trigeminal neuralgia has not been fully elucidated, although the microvascular compression in the trigeminal root entry zone is generally considered to be involved in the emergence and progression of the pain disorder. In addition, orofacial neuropathic pain restricted to one or more divisions of the trigeminal nerve might be secondary to peripheral nerve injury. Based on current hypotheses regarding the potential causes, a variety of animal models have been designed to simulate the pathogenesis of trigeminal neuralgia, including models of compression applied to the trigeminal nerve root or trigeminal ganglion, chronic peripheral nerve injury, peripheral inflammatory pain and center-induced pain. However, it has not yet been possible to determine which model can be perfectly employed to explain the mechanisms. The selection of appropriate animal models is of great significance for the study of trigeminal neuralgia. Therefore, it is necessary to discuss the characteristics of the animal models in terms of animal strains, materials, operation methods and behavior observation, in order to gain insight into the research progress in animal models of trigeminal neuralgia. In the future, animal models that closely resemble the features of human trigeminal neuralgia pathogenesis need to be developed, with the aim of making valuable contributions to the relevant basic and translational medical research.
Topics: Animals; Humans; Trigeminal Neuralgia; Quality of Life; Mastication; Models, Animal; Peripheral Nerve Injuries; Neuralgia
PubMed: 38615165
DOI: 10.11817/j.issn.1672-7347.2024.230279 -
Journal of Clinical Medicine Mar 2024Older adults who have undergone surgery for oral tumors are at increased risk of impaired masticatory rhythm. This study investigated the correlations between...
Older adults who have undergone surgery for oral tumors are at increased risk of impaired masticatory rhythm. This study investigated the correlations between masticatory rhythm, objective masticatory performance, and subjective masticatory performance as well as factors related to masticatory rhythm. The participants were 44 adults (24 men, 20 women; age range 42~90 years old) who had undergone maxillectomy, mandibulectomy, or glossectomy and were rehabilitated with a maxillofacial prosthesis. The number of functional contact teeth pairs was confirmed by intraoral examination. Chewing rate, cycle duration, coefficient of variation (CV) for cycle duration (reflecting the stability of masticatory rhythm), and mixing ability were measured simultaneously using a mastication movement rhythm tracking device during gum chewing. Maximum occlusal force was measured using the dental prescale system. Patients' perception of chewing ability was rated using a questionnaire. The Spearman's rank correlation test revealed that mixing ability, patient-rated masticatory scores, cycle duration, CV for cycle duration, and maximum occlusal force showed significant correlations with chewing rate. Multiple linear regression analysis identified mixing ability and the CV for cycle duration as significant predictors of masticatory rhythm. Factors associated with a faster chewing rate were higher mixing ability and masticatory scores, greater maximum occlusal force, shorter cycle duration, and smaller CV for cycle duration. Stable masticatory rhythm and mixing ability are significant predictors of chewing rate. Poor masticatory performance and unstable masticatory rhythm can result in slower chewing and thus a higher risk of inadequate dietary intake.
PubMed: 38610691
DOI: 10.3390/jcm13071926 -
Neuropsychopharmacology Reports Jun 2024Oral function in patients with schizophrenia has not been well-characterized. To address this, we performed a cross-sectional study of oral function in Japanese...
AIM
Oral function in patients with schizophrenia has not been well-characterized. To address this, we performed a cross-sectional study of oral function in Japanese inpatients with schizophrenia.
METHODS
We measured oral function, including occlusal force, tongue-lip motor function, tongue pressure, and masticatory function in 130 Japanese inpatients with schizophrenia. We then compared the frequency of clinical signs of oral hypofunction among 63 non-elderly and 67 elderly inpatients with schizophrenia, as well as data from 98 elderly control participants from a previous Japanese study.
RESULTS
The frequency of reduced occlusal force was significantly higher in the elderly inpatients (76.2%) than in the non-elderly inpatients (43.9%) and elderly controls (43.9%). The frequency of decreased tongue-lip motor function in non-elderly inpatients (96.8%) and elderly inpatients (97.0%) was significantly higher than that in elderly controls (56.1%). The frequency of decreased tongue pressure in non-elderly inpatients (66.1%) and elderly inpatients (80.7%) was significantly higher than that in elderly controls (43.9%). Finally, the frequency of decreased masticatory function was highest in elderly inpatients (76.5%), followed by non-elderly inpatients (54.8%) and elderly controls (15.3%).
CONCLUSION
Oral function was decreased in both non-elderly and elderly Japanese inpatients with schizophrenia compared with elderly controls.
Topics: Adult; Aged; Female; Humans; Male; Middle Aged; Bite Force; Cross-Sectional Studies; East Asian People; Inpatients; Japan; Lip; Mastication; Schizophrenia; Tongue
PubMed: 38602056
DOI: 10.1002/npr2.12443 -
Journal of Maxillofacial and Oral... Apr 2024Frey's syndrome, described by Lucy Frey in 1923, is a unique condition characterized by sweating, flushing, and reddening as a direct response to mastication. This...
INTRODUCTION
Frey's syndrome, described by Lucy Frey in 1923, is a unique condition characterized by sweating, flushing, and reddening as a direct response to mastication. This phenomenon results from the aberrant regeneration of postganglionic parasympathetic neurons originating from the auriculotemporal nerve and the subsequent acetylcholine secretion induced by masticatory stimuli. Although rare, this syndrome can have multiple underlying causes and is frequently observed, occurring in up to 65% of cases following lateral parotid resections. Additionally, it can less commonly manifest after neck dissection, facelift procedures, or be associated with diabetes mellitus.
METHOD
This article outlines a comprehensive diagnostic algorithm for Frey's syndrome, which includes the utilization of the Minor-Starch-Iodine Test. This test is a key component in diagnosing the syndrome and is discussed in detail, providing insights into its procedure and interpretation. Additionally, the gold standard of treatment for established Frey's syndrome, botulinum toxin A, is thoroughly described, including its mechanism of action, administration, and potential side effects.
DISCUSSION
Finally, the article underscores the need for further research to enhance our understanding of Frey's syndrome, leading to better diagnostic methods and more tailored treatment options for patients.
PubMed: 38601257
DOI: 10.1007/s12663-023-02029-9 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Dec 2023Cemento-ossifying fibroma (COF) is a mesenchymal benign odontogenic tumor, which may lead to impacted or ectopic permanent teeth. Autotransplantation of teeth is a...
Cemento-ossifying fibroma (COF) is a mesenchymal benign odontogenic tumor, which may lead to impacted or ectopic permanent teeth. Autotransplantation of teeth is a surgical process, in which a tooth is transplanted from one position to another in the same individual. This method can effectively restore the patient's mastication and aesthetics and is feasible in replacing missing teeth. This study reports a case of simultaneous COF resection combined with heterotopic canine autotransplantation to repair dentition defect, which effectively promotes the restoration of bone continuity and stability and achieves immediate and long-term aesthetic function requirements.
Topics: Humans; Cementoma; Transplantation, Autologous; Esthetics, Dental; Fibroma, Ossifying; Odontogenic Tumors
PubMed: 38597041
DOI: 10.7518/hxkq.2023.2023103