The history of occlusal theories can be traced with the history of the articulators. The study of mandibular movements, especially that of condylar movements, is central to the history of oc clusal theories. The purpose of this paper is to examine the study of condylar movements and the evolution of the articulatorʼs condylar path design. In this review, I exclude the interpretations by later generations and reconstruct the perspectives of the time. This in turn reveals how far the conventional history of the scholarship in question has deviated from the original. First, W. G. A. Bonwill left as his legacy an anatomical articulator with two articulations like the human temporomandibular joint (1864) as a result of his pursuit for principle system of occlusion based on objective observational data. In 1897, Walker developed a physiological ar ticulator with adjustable tilt and anteroposterior movements of the working condyle to reproduce the individual differences in human occlusion (1897), and he learned about Luceʼs precise mea surement of condylar movements (1889); but he then went beyond that to reveal the relationship between condylar movements and occlusal surface morphology. Walker devised a mechanism for anteroposterior adjustment of the working condyle by placing a fulcrum on the intercondylar axis (wippunkt), though is largely neglected today (this mechanism is todayʼs regulation of intercondy lar distance). Gysi inherited and improved on Walkerʼs articulator with the Wippunkt articulator (1908), which was able to adjust the condylar path inclination and anteroposterior movements of working condyle, but a paper on Bennett movement published in the same year pointed out that this could not be reproduced. After four years of hard work, Gysi developed an Adaptable Ar ticulator that could reproduce Bennett movement (1912), and then introduced the Gysi Symplex (1914), by averaging values of Adaptable Articulator. In the meantime, Bennett stated: “The condylar movements differ between the lateral move ment with the teeth contact or without teeth contact. Furthermore, the lateral excursion with the teeth contact moves the working condyle not only laterally but also slightly downwardly”. This discovery was for the large part ignored by the prosthodontic societies and is wrongly interpreted today as a mere shift in the direction of movement. Meanwhile, Gysiʼs Adaptable Articulator has a lower reputation in the United States, and most of the literature wrongly refers to it as Wip punkt Articulator, and in effect, it is settled as Wippunkt Articulator even in Japan. Later, Gysi developed TRUBYTE Articulator (1926), a condylar type, with independent mechanism of Ben nett movement and with the anteroposterior regulation of the working condyle by the incisal guidance. TRUBYTE Articulator influenced later developments of Hanau University Articulator and Stuart Articulator.
From the 1960s, when children began to be said to be somewhat strange, to the present day, the “abnormality” of the body has been increasingly seen by more and more children. Above all, the problem of posture represented by the word “straight neck” is that the center of gravity of the head moves forward, so the head must be supported only by the neck muscles. As a result, the muscles become tense and symptoms such as chronic neck pain and stiff shoulders appear. Poor posture has been shown to affect not only the appearance but also the childʼs growth and malocclusion, poor respiratory function, and academic achievement. Recently in the field of orthodontics, there has been increased interest in the relationship between jaw and head position, sleep apnea, and equivocal symptoms occurring in head, neck and shoulder. Since the craniomaxillofacial is supported by the cervical, thoracic and lumbar vertebrae, the head position might have some biomechanical connection to total body posture. Therefore, it is important to check the jaw position, head position, and the body posture.
In the case of a full mouth restoration, if there is no apparent reduction in the vertical dimension, opportune bite raising upon crown restoration should be kept to minimum. How ever, whether to preserve vertical dimension or to raise the bite can be a delicate question when the clinical crown length is not sufficient. This report is to present a case of occlusal reconstruction for a 58-year-old female patient with little posterior occlusal support. The initial plan was to restore the function of the molar with full-mouth restoration. After careful consideration on the pros and cons of bite raising by diagnostic wax-up, a full mouth restoration was performed while preserving the vertical dimension despite the short crown length. As a result, minimally invasive full-mouth restoration was achieved while preserving tooth structure and pulp.
This is a case of a patient (age 60, female) with mandibular bilateral free end missing, involving partial anterior crossbite, where functional recovery was eventually achieved by occlusal reconstruction using partial denture. In such cases, provision of the anterior coupling by orthodontic treatment and recovery of occlusal support by implant would be the standard approach. However, as per the patientʼs request, the second best solution was applied, namely, morphological correction of anterior teeth by crown prostheses and occlusal reconstruction by replacing mandibular bilateral free end space with partial denture using the altered cast technique to revise the stress distribution and the tissue displacement over alveolar ridge mucosa and support tooth. Provisional restorations based on diagnostic wax-ups were fitted, and the appropriate mandibular position was explored by trial and error. Second provisional restorations confirmed posterior disclusion during forward and lateral movements on a semi-adjustable articulator, so the final prostheses were duly fabricated and set. As of 6 years follow up of the setting of the final restoration, the ceramics chipping of the maxillary anterior teeth was occurred, however, the patient has not complained of any problems. During six year followup, chipping was observed in the ceramics of the maxillary anterior teeth, but the patient presented no complaint.
Orthodontic extrusion is the first choice for less invasive tooth preservation treatment in young patients with subgingival fractures. However, there are cases where intentional replantation should be considered as treatment options taking into account the treatment period and the crown/root ratio. In the present case, intentional replantation was selected in consideration of the fracture region and aesthetics. Aesthetically and structurally stable crown restorations were achieved with zirconia as the crown material, with consideration for the harmony with the gingival morphology taking advantage of the provisional restorations as well as securing the ferrule without changing the root length. We report as positive results were obtained.
In the treatment and prevention of periodontal disease, appropriate and mutually coordinated approach based on the vision shared by the dentist and dental hygienist can influence the management and improvement of the progression of the disease. The onset and progression of periodontal disease should be dealt with as early as possible by making a diagnosis based on an accurate examination. Periodontal disease is a multifactorial disease, but in its treatment, the emphasis is placed on bacterial factors and the control of plaque is prioritized. However, in the event of localized periodontal tissue abnormalities, my clinical experience suggests that cases affected by trauma factors as local modifiers are not necessarily rare. Therefore, in some cases removal of aggressive trauma factors need be prioritized. With this proactive intervention, the initial lesions of localized periodontal tissue can be expected to improve early. In this report, discussed are two cases of localized periodontal tissue abnormalities judged as caused mainly by trauma factors (traumatic occlusion), where removal of trauma factors was prioritized in cooperation with dentists.
Since dental clinics are environment with a high risk of infection for both patients and staff, thorough infection control is required. In order to block the contact infection route, which is the main cause of nosocomial infection, it is necessary to prevent the transmission of microorganisms through indirect contact. At the same time, it is important to raise patientsʼ awareness and also have them feel protected, for establishment of mutual rapport. In our hospital, we make sure to "show" patients the infection control measures such as the use of barrier films and disposable equipment. We report on the establishment of rapport with patients using infection control methods in our clinic.