-
Dentistry Journal Mar 2024This study assessed the masticatory function of participants wearing clear aligners in order to determine whether these devices can be worn even when eating and...
This study assessed the masticatory function of participants wearing clear aligners in order to determine whether these devices can be worn even when eating and therefore worn to extend treatment time and boost treatment effectiveness. An intercontrol test was conducted on 20 patients who received Invisalign treatment. Each participant was instructed to chew two pieces of Hue-Check Gum chewing gum (one pink and the other blue) in 5, 10, and 20 cycles both with and without aligners. After being removed from the oral cavity, the gum was dried and pressed using a 1 × 50 × 50 mm model that was 3D printed with a transparent layer in between. After being scanned on both sides with a flatbed scanner at 600 dpi, the samples were saved as jpg files and subjected to an optoelectronic examination using ViewGum software. To validate the procedure, a control group from a different institution (University of Bern) was used. A statistical analysis of the data was carried out. The Shapiro-Wilk test was used to confirm the normality of the samples. A one-way ANOVA test, a homogeneity of variance test, and a t-test did not reveal statistically significant differences between the two control groups, thus validating the methodology employed. In summary, clear aligners do not radically change the masticatory function while they are worn. As a result, clinicians can exploit the aligners for chewing to obtain a better fit of the plastic material to the dental surface and to attachments. Treatment times for patients could also be shorter.
PubMed: 38534281
DOI: 10.3390/dj12030057 -
Biology Letters Mar 2024In assessments of skeletal variation, allometry (disproportionate change of shape with size) is often corrected to examine size-independent variation for hypotheses...
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 (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.
Topics: Animals; Biological Evolution; Bite Force; Macropodidae; Skull
PubMed: 38531413
DOI: 10.1098/rsbl.2024.0045 -
BMC Oral Health Mar 2024To compare the crown accuracy and time efficiency of a complete digital workflow, utilizing an auxiliary occlusal device and IO scanning, with a conventional workflow,... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
To compare the crown accuracy and time efficiency of a complete digital workflow, utilizing an auxiliary occlusal device and IO scanning, with a conventional workflow, for multiple implant-supported single crowns.
MATERIALS AND METHODS
24 patients with two adjacent posterior implants were included. 12 patients were randomly assigned to digital workflow group, involving intra-oral scanning with an auxiliary occlusal device and manufacture of customized abutments and zirconia single crowns (test group). The other 12 were assigned to the conventional workflow (control group), involving conventional impression and CAD-CAM crowns based on stone casts. Crown scanning was done before and after clinical adjustment using an intraoral scanner. Two 3D digital models were overlapped to assess dimension changes. Chair-side and laboratory times for the entire workflow were recorded and a linear mixed model and Independent-sample t tests were used for the statistical analysis.
RESULTS
The maximum occlusal deviation was 279.67 ± 112.17 μm and 479.59 ± 203.63 μm in the test and control group, respectively (p < 0.001). The sizes of the occlusion adjustment areas were 12.12 ± 10.51 mm and 25.12 ± 14.14 mm in the test and control groups, respectively (p = 0.013). The mean laboratory time was 46.08 ± 5.45 and 105.92 ± 6.10 min in the test and control groups, respectively (p < 0.001).The proximal contact adjustment and mean chair-side time showed no statistically significant difference between two groups.
CONCLUSIONS
A digital workflow for two implants-supported single crowns using an auxiliary device required fewer occlusal crown adjustments, and less laboratory time compared to conventional workflow.
CLINICAL RELEVANCE
The use of auxiliary occlusal devices in IOS enhances the accuracy of virtual maxillomandibular relationship in extended edentulous spans. Consequently, employing a digital workflow for multiple implants-supported crowns using IO scanning and an auxiliary occlusal device proves to be a feasible, accurate and efficient approach.
Topics: Humans; Workflow; Dental Prosthesis Design; Dental Implants; Crowns; Computer-Aided Design
PubMed: 38519905
DOI: 10.1186/s12903-024-03986-4 -
Journal of Neuromuscular Diseases 2024Hereditary proximal spinal muscular atrophy (SMA) is characterized by abnormal alpha motor neuron function in brainstem and spinal cord. Bulbar dysfunction, including... (Observational Study)
Observational Study
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 (β= -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.
Topics: Humans; Male; Female; Adult; Prospective Studies; Longitudinal Studies; Spinal Muscular Atrophies of Childhood; Mandible; Young Adult; Adolescent; Bite Force; Middle Aged; Mastication; Disease Progression
PubMed: 38517801
DOI: 10.3233/JND-240007 -
BMC Oral Health Mar 2024Clear aligner therapy has gained popularity as a minimally invasive orthodontic treatment option. However, its impact on the masticatory musculature and the...
Impact of clear aligner therapy on masticatory musculature and stomatognathic system: a systematic review conducted according to PRISMA guidelines and the Cochrane handbook for systematic reviews of interventions.
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.
Topics: Humans; Masticatory Muscles; Stomatognathic System; Dental Occlusion; Bite Force; Orthodontic Appliances, Removable
PubMed: 38504207
DOI: 10.1186/s12903-024-04029-8 -
BDJ Open Mar 2024To assess the attitude and practices of dentists and dental assistants in managing dust particles generated during dental prostheses or appliances grinding and polishing.
OBJECTIVES
To assess the attitude and practices of dentists and dental assistants in managing dust particles generated during dental prostheses or appliances grinding and polishing.
MATERIALS AND METHODS
Data were collected from 207 dentists and 125 dental assistants through an online questionnaire. The questionnaire included adjusted prosthesis types, self-protective methods, types and frequency of protective device use, and reasons for non-frequent use.
RESULTS
Protective grinding devices, including dust protective boxes and mounted plastic sheets, were commonly used for substantial acrylic resin adjustments, while air blowing was preferred for minor adjustments. Post-COVID-19, there was a 3-fold increase in the use of protective grinding devices among dentists and a 1.3-fold increase among dental assistants. During try-in procedures, dentists commonly rinsed prostheses with water rather than using disinfectants. Non-frequent users adopted self-protection methods, such as face shields and air filters. Surgical drapes and high-volume evacuators were used for patient's protection.
CONCLUSION
Despite an increased tendency of the use of protective grinding devices following COVID-19, a significant number still report infrequent use. Identified protective devices in this study have drawbacks not fully meeting dentists' expectations. Invention of a more user-friendly device is necessary to ensure regular use, preventing potential toxicity from dust particles.
PubMed: 38503744
DOI: 10.1038/s41405-024-00206-7 -
Biomechanics and Modeling in... Jun 2024Total temporomandibular joint replacement (TMJR) surgery is the established treatment for severe temporomandibular joint disorders. While TMJR surgery is known to...
Total temporomandibular joint replacement (TMJR) surgery is the established treatment for severe temporomandibular joint disorders. While TMJR surgery is known to increase mouth-opening capacity, reduce pain and improve quality of life, little is known about post-surgical jaw function during activities of daily living such as biting and chewing. The aim of this study was to use subject-specific 3D bite force measurements to evaluate the magnitude and direction of joint loading in unilateral total TMJR patients and compare these data to those in healthy control subjects. An optoelectronic tracking system was used to measure jaw kinematics while biting a rubber sample for 5 unilateral total TMJR patients and 8 controls. Finite element simulations driven by the measured kinematics were employed to calculate the resultant bite force generated when compressing the rubber between teeth during biting tasks. Subject-specific musculoskeletal models were subsequently used to calculate muscle and TMJ loading. Unilateral total TMJR patients generated a bite force of 249.6 ± 24.4 N and 164.2 ± 62.3 N when biting on the contralateral and ipsilateral molars, respectively. In contrast, controls generated a bite force of 317.1 ± 206.6 N. Unilateral total TMJR patients biting on the contralateral molars had a significantly higher lateral TMJ force direction (median difference: 63.6°, p = 0.028) and a significantly lower ratio of working TMJ force to bite force (median difference: 0.17, p = 0.049) than controls. Results of this study may guide TMJ prosthesis design and evaluation of dental implants.
Topics: Humans; Bite Force; Temporomandibular Joint; Biomechanical Phenomena; Female; Male; Finite Element Analysis; Middle Aged; Adult; Arthroplasty, Replacement; Mastication; Case-Control Studies; Muscles; Temporomandibular Joint Disorders
PubMed: 38502434
DOI: 10.1007/s10237-023-01807-1 -
Cureus Feb 2024Temporomandibular disorders (TMD) originate from various components within the temporomandibular joint (TMJ), causing an impact on the masticatory muscles, the joint... (Review)
Review
Temporomandibular disorders (TMD) originate from various components within the temporomandibular joint (TMJ), causing an impact on the masticatory muscles, the joint itself, and associated structures. They are a widely prevalent issue across the world. According to epidemiological research, up to 50% of adults in the population have TMD-related symptoms. The objective of this work was to analyze the existing scientific literature regarding the association between malocclusion classes, bruxism, and tooth loss in relation to the etiology of TMD. This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 analysis protocol. For the development of the question focus, the population, intervention, control, and outcomes (PICO) study design protocol was used. The question in focus according to the PICO format was: "Do malocclusion, tooth loss, and bruxism contribute to temporomandibular disorders?". The review was performed with articles from PubMed, Web of Science, and Google Scholar databases according to the specified inclusion and exclusion criteria. The included articles were not older than five years. The risk of bias was assessed in the included studies by using the Cochrane Risk-of-bias 2 (RoB-2) tool. Out of a total of 32 results received, 21 articles were chosen according to the established criteria after conducting a review and analysis of their full texts. The article search sequence was presented in the PRISMA 2020 flow diagram, and the outcomes of the chosen articles were presented. The literature results revealed a relationship between occlusion and the development of TMD. The influence of occlusal factors on the TMJ was explained by an examination of joint anatomy and symptoms related to TMD. This study revealed variations in TMJ factors across different malocclusion classes. Additionally, it was observed that the occurrence and attributes of TMD are influenced by the number of tooth loss quadrants and the frequency of missing teeth. Furthermore, a correlation was found between bruxism and the symptoms of TMD, including myofascial pain, disc displacement, arthralgia, and muscle disorders. This literature review provides comprehensive information on the relationship between malocclusion classes, bruxism, tooth loss, and TMDs. This prompts healthcare professionals to prioritize patients' occlusal assessment and TMJ condition.
PubMed: 38487145
DOI: 10.7759/cureus.54130 -
PloS One 2024The current body of research on utilizing botulinum toxin (BTX) to manage temporomandibular disorders (TMDs) has not yet yielded definitive conclusions. The primary... (Meta-Analysis)
Meta-Analysis
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.
Topics: Humans; Botulinum Toxins, Type A; Bruxism; Pain; Temporomandibular Joint Disorders; Bite Force
PubMed: 38483856
DOI: 10.1371/journal.pone.0300157 -
Journal of Prosthodontic Research Mar 2024This prospective cohort study examined the effects of the number of present and functional teeth on mortality among older Japanese adults requiring nursing care in an...
PURPOSE
This prospective cohort study examined the effects of the number of present and functional teeth on mortality among older Japanese adults requiring nursing care in an environment of comprehensive oral hygiene and nutritional management.
METHODS
The study included 174 older adults (mean age: 84.4 ± 8.3 years; male/female: 49/125) in need of support or long-term care, who resided in either a local specialized healthcare facility or their own homes, and received daily oral hygiene and nutritional support at facilities in Okayama, Japan. The initial clinical oral examination along with assessment of general physical condition and nursing environment of the participants were performed in July 2013 and followed up for one year.
RESULTS
All-cause mortality occurred in 28 (mean age: 88.7 ±13.4 years; male/female: 6 /22) individuals during the follow-up period. Cox proportional hazard analysis indicated that older age, low performance in activities of daily living (Barthel Index <40), and underweight status (body mass index <18.5) were significant risk factors for mortality. The number of present and functional teeth were not found to be significant risk factors for mortality.
CONCLUSIONS
During the one-year follow-up period, the number of present and functional teeth did not have a significant impact on mortality among older Japanese adults requiring nursing care in a well-managed environment of oral hygiene and nutritional status.
PubMed: 38479889
DOI: 10.2186/jpr.JPR_D_23_00221