The result of instrumental analysis of the amount of motion in patients with different occlusive and skeletal classes according to the condylography

The temporomandibular joint is paired, a complex formation of an ellipsoid shape, which is formed by the articular head of the lower jaw, the mandibular fossa and the articular tubercle of the temporal bone, covered with fibrous cartilage. There are two types of movements in the temporomandibular joint: translation and rotation, which implement protrusion-retrusion, right and left mediotrusion, and opening-closing. Computerized axiography is used for assessment of the mandibular movements and the patient’s skeletal parameters. This type of examination allows you to adjust the articulator for an individual function and to study the qualitative and quantitative characteristics of the temporomandibular joint.

Functional Removable Prosthetic Rehabilitation Using the Electronic Condylograph: A Case Report

This article describes the design of complete removable prostheses following the Slavicek philosophy, which involves the integration between condylographic data and an individual cephalometric study of the patient. The electronic condylograph is a device that records the mandibular movements made by the patient. This case report shows how condylography data are useful not only in the individual articulator setting, but also for diagnostic completion and for planning a functional prosthetic rehabilitation.

METHODS OF DEPROGRAMMING THE MASTICATORY MUSCLES: LITERATURE REVIEW

Deprogramming of masticatory group muscles is an integral step in determining and fixing the centric jaw relation in the diagnosis and treatment of patients with orthopedic and orthodontic pathology of the maxillary system. The review presents the main methods for determining the centric jaw ratio using deprogramming of masticatory muscles, as well as indications for the use of these methods. In complete adentia, the most acceptable are the method of non-forced control of the mandibular movements, the Dawson method, the Schiler method, the method of recording the Gothic angle, transcutaneous electroneurostimulation. The above-listed methods can be used in partial adentia as well, and in the presence of all teeth in the oral cavity. In the pathology of the temporomandibular joint, deprogramming methods using the Lucia jig, a leaf gauge, Sliding Guide, as well as the method of recording the Gothic angle will also perform a diagnostic function. With the help of these methods, it is possible to change the design of long-wearing deprogrammers and medical devices. The most universal of these methods are the method of electronic recording of the Gothic arch and transcutaneous electroneurostimulation.

Prosthetic Management of Segmentally Resected Mandible and Partial Glossectomy: A Case Report

The balance and symmetry of mandibular function gets destroyed by the loss of continuity of the mandible, which deviates the residual fragment towards the resected side thereby altering the mandibular movements. Physical therapy in combination with prosthodontic treatment can be used to reduce the mandibular deviation and hence it improves the masticatory efficiency. Many prosthetic methods are discovered to minimize deviation and provide masticatory efficiency. Some of these methods are mandibular guide flange prosthesis, implant supported prosthesis and palatal guidance restoration. Contact of Tongue with palate is important for the production of normal speech, also the proper place of the tongue during certain sounds is important. In partial glossectomy conditions, tongue to palate articulation gets affected during speech and patient faces difficulty to pronounce certain sounds. For the rehabilitation of such patient thorough knowledge of the production of different sounds can be useful for diagnosis and treatment planning.

Incidence of Malocclusion among Young Patients with Gingival Recessions—A Cross-Sectional Observational Pilot Study

Background and Objectives: Dental occlusion and gingival recession have been studied over the past years especially because of the increasing incidence of occlusal interferences in young patients. The purpose of this pilot study is to investigate any association between occlusal dysfunctions and gingival recessions. Data on gingival phenotype and previous orthodontic treatment were also collected to assess any correlation with the presence of gingival recession. Materials and Methods: Forty systemically healthy subjects, without signs of periodontitis and with gingival recessions, were included in the study. The following parameters were determined: location and extent of the gingival recession, gingival phenotype and functional occlusion by means of observing and registering the occlusal contacts in maximum intercuspation position, protrusive and lateral guidance. Results: Premolars were mostly affected in cases of working-side interferences during lateral guidance (71.19% of the affected teeth during left and 75% during right mandibular movements). The chi-squared exact test applied for the analysis of contingency tables revealed statistically significant associations between excursive interferences during lateral guidance and anterior guidance and the presence of gingival recession on the involved group of teeth. Conclusions: The results suggest that most gingival recessions might be associated with working-side interferences, the highest number of gingival recessions being associated with active interferences during lateral guidance.

Visualization of mandibular movement relative to the maxilla during mastication in mice: integration of kinematic analysis and reconstruction of a three-dimensional model of the maxillofacial structure

Background Mastication is one of the most fundamental functions for the conservation of human life. To clarify the pathogenetic mechanism of various oral dysfunctions, the demand for devices for evaluating stomatognathic function has been increasing. The aim of the present study was to develop a system to reconstruct and visualize 3-dimensional (3D) mandibular movements relative to the maxilla, including dynamic transition of occlusal contacts between the upper and lower dentitions during mastication in mice. Methods First, mandibular movements with six degrees of freedom were measured using a motion capture system comprising two high-speed cameras and four reflective markers. Second, 3D models of maxillofacial structure were reconstructed from micro-computed tomography images. Movement trajectories of anatomical landmark points on the mandible were then reproduced by integrating the kinematic data of mandibular movements with the anatomical data of maxillofacial structures. Lastly, 3D surface images of the upper dentition with the surrounding maxillofacial structures were transferred to each of the motion capture images to reproduce mandibular movements relative to the maxilla. We also performed electromyography (EMG) of masticatory muscles associated with mandibular movements. Results The developed system could reproduce the 3D movement trajectories of arbitrary points on the mandible, such as incisor, molars and condylar points with high accuracy and could visualize dynamic transitions of occlusal contacts between upper and lower teeth associated with mandibular movements. Conclusions The proposed system has potential to elucidate the mechanisms underlying motor coordination of masticatory muscles and to clarify their roles during mastication by taking advantage of the capability to record EMG data synchronously with mandibular movements. Such insights will enhance our understanding of the pathogenesis and diagnosis of oral motor disorders by allowing comparisons between normal mice and genetically modified mice with oral behavioral dysfunctions.

Virtual Articulators, Virtual Occlusal Records and Virtual Patients in Dentistry

Digital technology is broadly used in almost every part of medicine. As tools of digital technology, augmented reality and virtual reality have been adopted in all disciplines of dentistry and dental education. In particular, virtual articulators have allowed for a full analysis of occlusion with dental models that can simulate all mandibular movements in static and dynamic positions. When combined with additional software, virtual articulators can also enhance education and practice, allow for quicker and more precise individualized diagnoses and enable discussions of dental treatment planning options with patients during their first appointment. This article reviews the requirements for virtual articulators and occlusal recordings and assesses their advantages and disadvantages in various aspects.

The Influence of Altering the Morphology of the First Mandibular Molar on Functional Mandibular Movements: A Pilot Study

Purpose: Altering the tooth morphology is a frequent clinical situation and it requires replacing the lost tooth substance by direct/indirect treatment methods. The purpose of this study is to identify the optimal study group size to quantify the extent to which the change in dental morphology influences the amplitude and path of the mandibular movements at the condylar and dental level. Materials and Methods: The study was performed on 10 young participants, without associated joint pathology, with healthy complete dentition. The Zebris JMA System (Zebris Medical GmbH, Germany) condylograph were used. The condylar and occlusal parameters were registered, before and after the composite occlusal modification on the right first mandibular molar was made and data were synthesized as Excel Data. The SPSS2 software was used for statistical analyses, a descriptive analysis of the pair differences was performed, Kolmogorov-Smirnova and Shapiro-Wilk tests were applied to verify the normality, paired sample test for 0,05 level of significance and 80% power was applied to determine the proper sample size. Conclusion: The results show a change in movement parameters at both condylar and dental level: the sagittal motion of the condyle on both sides tends to have a more vertical trajectory, the incisal guidance in protrusion and the guidance in the lateral movement on the modified part are steeper, lateral movement guidance on the other side is shallower, a tendency of retrusion is noted in both condyles. Respecting original dental morphology is essential for functional harmonious integration of the restoration.