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Biomedicines Jul 2023The goal of the current study was to determine the mechanical proprieties of polymethylmethacrylate (PMMA) and the improved compound, the graphene-based PMMA, with Zn...
The goal of the current study was to determine the mechanical proprieties of polymethylmethacrylate (PMMA) and the improved compound, the graphene-based PMMA, with Zn and Ag and to compare the results. Scanning electron microscopy analysis of the samples before and after the mechanical test was conducted. The compression behavior, flexural properties, tensile strength, and shape of the samples were all investigated and compared between the variants of PMMA. Commercially available polymethylmethacrylate was used (Orthocryl-Dentaurum, Ispringen, Germany) with the salt and pepper technique according to the manufacturer's instructions to produce 20 samples for each mechanical trial with standard cylinders (4 mm diameter × 8 mm length) for compression, parallelepipedal prisms for flexing (2 mm × 2 mm × 25 mm) and flat samples for traction. There was no statistical difference in the mechanical proprieties of the samples evaluated, although there were values that could suggest significance. The graphene-based PMMA demonstrated good mechanical proprieties, like the commercially available PMMA, and appears promising for future clinical use based on its multiple advantages.
PubMed: 37509604
DOI: 10.3390/biomedicines11071965 -
Folia Medica Cracoviensia Apr 2023Temporomandibular disorder (TMD) is a disease of multifactorial etiology and a complex of symptoms, related to disorders of the masticatory muscles, temporomandibular... (Review)
Review
Temporomandibular disorder (TMD) is a disease of multifactorial etiology and a complex of symptoms, related to disorders of the masticatory muscles, temporomandibular joints and the surrounding orofacial structures. One of the main problems in the course of TMD disorders is the systematic increase in the tension of the masticatory muscles (masseter muscles, temporalis and medial and lateral pterygoid muscles), what is the cause of many damages and the development of pathological conditions in the stomatognathic system. The article discusses the differences in the structure of the masticatory and skeletal muscles, as well as the different nature and isoforms of myosin, which determines the much faster generation of contraction in the masticatory muscles and consequently easier generation of excessive, harmful tensions in the masticatory muscles. The article describes the causes of increased tension in the masticatory muscles and methods of their relaxation used in the basic and supportive treatment of temporomandibular disorders. The use of occlusal splints, physiotherapeutic procedures and TMD treatment with botulinum toxin type A were characterized. A role of psychological support and the methods used for patients with TMD were emphasized.
Topics: Humans; Temporomandibular Joint Disorders; Masticatory Muscles; Masseter Muscle; Temporomandibular Joint; Occlusal Splints
PubMed: 37406276
DOI: 10.24425/fmc.2023.145429 -
BMC Oral Health Jun 2023The efficacy of mandibular advancement devices (MAD) and maxillomandibular advancement (MMA) in improving upper airway (UA) patency has been described as being...
BACKGROUND
The efficacy of mandibular advancement devices (MAD) and maxillomandibular advancement (MMA) in improving upper airway (UA) patency has been described as being comparable to continuous positive airway pressure (CPAP) outcomes. However, no previous study has compared MAD and MMA treatment outcomes for the upper airway enlargement. This study aimed to evaluate three-dimensionally the UA changes and mandibular rotation in patients after MAD compared to MMA.
METHODS
The sample consisted of 17 patients with treated with MAD and 17 patients treated with MMA matched by weight, height, body mass index. Cone-beam computed tomography from before and after both treatments were used to measure total UA, superior/inferior oropharynx volume and surface area; and mandibular rotation.
RESULTS
Both groups showed a significant increase in the superior oropharynx volume after the treatments (p = 0.003) and the MMA group showed greater increase (p = 0.010). No statistical difference was identified in the MAD group considering the inferior volume, while the MMA group showed a significantly gain (p = 0.010) and greater volume (p = 0.024). Both groups showed anterior mandibular displacement. However, the mandibular rotation were statistically different between the groups (p < 0.001). While the MAD group showed a clockwise rotation pattern (-3.97 ± 1.07 and - 4.08 ± 1.30), the MMA group demonstrated a counterclockwise (2.40 ± 3.43 and 3.41 ± 2.79). In the MAD group, the mandibular linear anterior displacement was correlated with superior [p = 0.002 (r=-0.697)] and inferior [p = 0.004 (r = 0.658)] oropharynx volume, suggesting that greater amounts of mandibular advancement are correlated to a decrease in the superior oropharynx and an increase in the inferior oropharynx. In the MMA group, the superior oropharynx volume was correlated to mandibular anteroposterior [p = 0.029 (r=-0.530)] and vertical displacement [p = 0.047 (r = 0.488)], indicating greater amounts of mandibular advancement may lead to a lowest gain in the superior oropharynx volume, while a great mandibular superior displacement is correlated with improvements in this region.
CONCLUSIONS
The MAD therapy led to a clockwise mandibular rotation, increasing the dimensions of the superior oropharynx; while a counterclockwise rotation with greater increases in all UA regions were showed in the MMA treatment.
Topics: Humans; Occlusal Splints; Nose; Body Mass Index; Cone-Beam Computed Tomography; Mandible
PubMed: 37391785
DOI: 10.1186/s12903-023-03125-5 -
Swiss Dental Journal Jul 2023This article discusses the treatment of tooth structure loss due to erosion using indirect lithium disilicate ceramic restorations. Minimally invasive approaches, in...
This article discusses the treatment of tooth structure loss due to erosion using indirect lithium disilicate ceramic restorations. Minimally invasive approaches, in which the eroded teeth are conservatively prepared and restored with minimally invasive restorations, are recommended. Lithium disilicate ceramics are currently the material of choice for this type of treatment as they can withstand maximum occlusal forces in the posterior region. The restorative process should be guided by diagnostic procedures that define the clinical therapeutic goal at the beginning of treatment. Adhesive cementation with the correct protocol is crucial for full mechanical strength of the restoration. At the end of the treatment, in addition to preventive measures, an overnight protective splint is recommended to ensure long-term clinical stability.
Topics: Humans; Esthetics, Dental; Tooth Loss; Back; Bite Force; Cementation
PubMed: 37386915
DOI: 10.61872/sdj-2023-07-08-05 -
Swiss Dental Journal Jul 2023The restorative treatment of dental hard tissue loss, e.g., due to erosion, and the rehabilitation of the original vertical bite dimension confronts the dentist with...
The restorative treatment of dental hard tissue loss, e.g., due to erosion, and the rehabilitation of the original vertical bite dimension confronts the dentist with problems when implementing the therapy. Traditionally, this therapy is conducted with laboratory-fabricated workpieces made of ceramics which usually require a preparation of the remaining tooth substance and also causes high costs for the patient. Therefore, alternative methods should be considered. This article presents the use of direct adhesive composite restorations as a way of reconstructing a dentition severely altered by erosion. To reconstruct the occlusal surfaces, transfer splints are used that are made on the basis of individual wax-up models. The procedure described is a well-researched and proven method for restoring teeth with erosion-related loss of hard tooth substance. As with all new procedures, there will be a certain learning curve for the practical dentist after which high-quality restorations can be implemented with this technique.
Topics: Humans; Tooth Attrition; Tooth Wear; Ceramics; Dental Occlusion; Exostoses
PubMed: 37386907
DOI: 10.61872/sdj-2023-07-08-04 -
Sleep & Breathing = Schlaf & Atmung Dec 2023Obstructive sleep apnea (OSA) is frequently treated with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs). For various reasons, both... (Review)
Review
PURPOSE
Obstructive sleep apnea (OSA) is frequently treated with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs). For various reasons, both treatment options are often affected by low adherence. While factors associated with low CPAP adherence are described in the literature extensively, less is known about adherence to MAD therapy. This scoping review aimed to synthesize the body of literature on the factors associated with adherence to MAD treatment.
METHODS
A systematic literature search was conducted using bibliographic databases PubMed, Embase.com , Web of Science, and the Cochrane Library (Wiley) to identify relevant studies that described factors associated with adherence to MAD in the treatment of OSA or snoring combined with OSA in adults.
RESULTS
The literature search yielded a total of 694 references. Forty studies were found eligible for inclusion. The literature showed that factors with a possible negative influence on the adherence to MAD treatment are personality aspects; failing effectiveness of MAD; side effects during MAD therapy; using a thermoplastic MAD; dental treatments during MAD therapy; and a poor first experience with the MAD with inadequate guidance by professionals. Factors that may have a positive effect on MAD adherence include effectiveness of therapy, custom-made MAD, good communication skills of the practitioner, early recognition of side effects, stepwise titration of the MAD, and positive first experience with MAD.
CONCLUSIONS
The knowledge of factors associated with MAD adherence can be used to provide further insight into individual adherence to OSA treatments.
Topics: Adult; Humans; Continuous Positive Airway Pressure; Mandibular Advancement; Occlusal Splints; Sleep Apnea, Obstructive; Treatment Adherence and Compliance; Treatment Outcome
PubMed: 37386300
DOI: 10.1007/s11325-023-02862-9 -
Clinical Oral Investigations Sep 2023To determine the accuracy of maxillary positioning using computer-designed and manufactured occlusal splints or patient-specific implants in orthognathic surgery.
OBJECTIVE
To determine the accuracy of maxillary positioning using computer-designed and manufactured occlusal splints or patient-specific implants in orthognathic surgery.
MATERIAL AND METHODS
A retrospective analysis of 28 patients that underwent virtually planned orthognathic surgery with maxillary Le Fort I osteotomy either using VSP-generated splints (n = 13) or patient-specific implants (PSI) (n = 15) was conducted. The accuracy and surgical outcome of both techniques were compared by superimposing preoperative surgical planning with postoperative CT scans and measurement of translational and rotational deviation for each patient.
RESULTS
The 3D global geometric deviation between the planned position and the postoperative outcome was 0.60 mm (95%-CI 0.46-0.74, range 0.32-1.11 mm) for patients with PSI and 0.86 mm (95%-CI 0.44-1.28, range 0.09-2.60 mm) for patients with surgical splints. Postoperative differences for absolute and signed single linear deviations between planned and postoperative position were a little higher regarding the x-axis and pitch but lower regarding the y- and z-axis as well as yaw and roll for PSI compared to surgical splints. There were no significant differences regarding global geometric deviation, absolute and signed linear deviations in the x-, y-, and z-axis, and rotations (yaw, pitch, and roll) between both groups.
CONCLUSIONS
Regarding accuracy for positioning of maxillary segments after Le Fort I osteotomy in orthognathic surgery patient-specific implants and surgical splints provide equivalent high accuracy.
CLINICAL RELEVANCE
Patient-specific implants for maxillary positioning and fixation facilitate the concept of splintless orthognathic surgery and can be reliably used in clinical routines.
Topics: Humans; Orthognathic Surgery; Occlusal Splints; Orthognathic Surgical Procedures; Retrospective Studies; Surgery, Computer-Assisted; Dental Implants; Maxilla; Computers; Imaging, Three-Dimensional; Osteotomy, Le Fort
PubMed: 37382718
DOI: 10.1007/s00784-023-05125-9 -
Cureus May 2023This clinical report details the successful rehabilitation of a 63-year-old male patient with severe tooth wear, a reduced vertical dimension of occlusion, and esthetic...
This clinical report details the successful rehabilitation of a 63-year-old male patient with severe tooth wear, a reduced vertical dimension of occlusion, and esthetic concerns. The Hobo twin-stage procedure addressed these issues while improving the patient's oral health and quality of life. After ensuring adequate oral hygiene, the treatment began with scaling and root planning, followed by diagnostic impressions. An occlusal splint was fabricated, followed by a diagnostic wax-up and tooth preparation. Full-arch impressions of prepared teeth were made using the addition of silicon elastomeric impression material, and chairside provisional crowns were fabricated. The working casts were mounted on a semi-adjustable articulator, and the metal copings were tried on before being built up in porcelain. The patient achieved successful outcomes and expressed satisfaction with the treatment. The Hobo twin-stage technique and porcelain-fused-to-metal crowns can be viable approaches for restoring the teeth's form and function while enhancing the patient's oral health and esthetics. However, regular follow-up appointments and good oral hygiene maintenance are essential for the long-term success of the treatment.
PubMed: 37378250
DOI: 10.7759/cureus.39260 -
Journal of Functional Biomaterials May 2023Three-dimensional printing has become incorporated into various aspects of everyday life, including dentistry. Novel materials are being introduced rapidly. One such...
Three-dimensional printing has become incorporated into various aspects of everyday life, including dentistry. Novel materials are being introduced rapidly. One such material is Dental LT Clear by Formlabs, a resin used for manufacturing occlusal splints, aligners, and orthodontic retainers. In this study, a total of 240 specimens, comprising two shapes (dumbbell and rectangular), were evaluated through compression and tensile tests. The compression tests revealed that the specimens were neither polished nor aged. However, after polishing, the compression modulus values decreased significantly. Specifically, the unpolished and nonaged specimens measured 0.87 ± 0.02, whereas the polished group measured 0.086 ± 0.03. The results were significantly affected by artificial aging. The polished group measured 0.73 ± 0.05, while the unpolished group measured 0.73 ± 0.03. In contrast, the tensile test proved that the specimens showed the highest resistance when the polishing was applied. The artificial aging influenced the tensile test and reduced the force needed to damage the specimens. The tensile modulus had the highest value when polishing was applied (3.00 ± 0.11). The conclusions drawn from these findings are as follows: 1. Polishing does not change the properties of the examined resin. 2. Artificial aging reduces resistance in both compression and tensile tests. 3. Polishing reduces the damage to the specimens in the aging process.
PubMed: 37367259
DOI: 10.3390/jfb14060295 -
BDJ Open Jun 2023To compare the surface wear rate between polymethyl methacrylate (PMMA)-based occlusal splints and opposing dentin-exposed teeth in bruxism simulating models.
OBJECTIVES
To compare the surface wear rate between polymethyl methacrylate (PMMA)-based occlusal splints and opposing dentin-exposed teeth in bruxism simulating models.
MATERIALS AND METHODS
PMMA-based occlusal splints and extracted premolars were tested on a chewing stimulator at 30,000 or 60,000 cycles. Dentin wear was measured under a stereomicroscope and PMMA wear was determined with an optical profilometer. In addition, wear surface topography was assessed and quantified by scanning electron microscopy (SEM).
RESULTS
Wear rate of PMMA was significantly greater (11 times) than that of dentin specimens at 60,000 cycles, though these findings were not observed at 30,000 cycles. When comparing wear rates within each group at different duration cycles, PMMA surfaces exhibited an average wear rate 1.4 times higher with high duration cycles, while dentin surfaces displayed a marginal decrease in wear. In SEM micrographs, PMMA surfaces displayed more wear abrasion lines with higher duration cycles. However, dentin surfaces did not exhibit major differences between low and high duration cycles.
CONCLUSION
Wear rate on PMMA-based occlusal splints remarkably increases upon high chewing cycles mimicking bruxism comparing with the rate on dentin. Hence, it is reasonable for bruxing patients to wear single-arch PMMA-based occlusal splints to protect opposing dentin-exposed teeth.
PubMed: 37301831
DOI: 10.1038/s41405-023-00148-6