Effects of Test Foods of Different Hardness and Size on Mandibular Movements and Occlusal Morphology.

One of the most important goals of prosthetic treatment is to make the occlusal morphology suitable for the patient's original anatomy. Mechanical articulators are metal devices that mimic the temporomandibular joint and lower jaw movements, and attempts have been made to make them patient-specific over the years. For this purpose, semi-adjustable articulators were first developed. Later, fully adjustable articulators were introduced to the market. Although these devices have the closest imitation mechanism to the patient's original anatomy, they have various limitations. Adjusting mechanical articulators and recording lower jaw movements have been researched in dentistry clinics and dentistry literature for many years. Due to the limitations of articulators, digital recordings of lower jaw movements have been started since 1989. Later, in 2002, the process of adjusting virtual articulators in a computer environment according to the digital recording data of the mandibular movements was started. In this way, the limitations of mechanical articulators such as metal deformation, difficulties experienced during recording, distortion of plaster and recording material, insufficient stability, adaptation problems of base plates, logistic problems between the laboratory and the physician, and inability to store data have been largely eliminated. In addition, mechanical articulators still cannot fully mimic the anatomy of the temporomandibular joint and related muscles. Digital recording of mandibular movements and transferring them to a virtual environment were first tried with electronic methods, and these systems were developed and ultrasonic and optoelectronic methods were used. Today, tooth movement records can be obtained with 3D video motion analysis methods. By superimposing these data with the data of digital models of the jaws, a mandibular movement recording method has been developed that can now produce restorations without the need for virtual or mechanical articulators. All these developments arise from the desire to record more appropriate and adaptable mandibular movement patterns, overcoming the difficulties in imitating complex patterns of mandibular movements that vary from the size, initial height and consistency of the food to the patient's mental state during the mandibular chewing movement. Thus, we will be able to obtain the most appropriate occlusal morphology for the patient to chew at maximum performance in the prosthetic or restorative procedures we will perform. With the developing technology, mandibular movement recordings can be recorded not only in the border movements as in the past, but also during chewing. In the literature, the majority of studies conducted by having the patient chew a test food are studies measuring the activity of the masticatory muscles, the distance between the incisors, the lateral movement distance or the magnitude of the chewing stroke.

For this reason, in this study, mandibular movements will be recorded with optical motion tracking systems and 4-unit fixed partial dentures(FPDs) for teeth 4.4 - 4.7 will be designed according the recordings.

The study will include individuals who are in the molar class 1 of the Angle classification, who have no temporomandibular joint and masticatory muscle disorders, who have no missing or extra teeth, who have no fillings or crowns on teeth numbered 4.4-4.7, who have not undergone orthodontics, and who are not allergic to the test foods. The subjects will sign a consent form. After the subjects are examined, lower and upper jaw scans and bite scans will be recorded. In the 2nd session, facebow records, border movements and chewing records with 5 different test foods will be recorded from the subjects with an optical lower jaw movement tracker(Zebris JMA Optic). These test foods were selected according to the literature and are cheese, raw carrots, boiled carrots, crispy bread and pre-polymerized silicone impression material. After recordings, fixed partial dentures will be designed via virtual articulator, border movement recordings and for 5 different foods in digital design program. 7 different FDPs designs for each subject will be overlapped with the subject's original anatomy in the Geomagic program.