Record Base (or Base Plate) Record bases (temporary denture base) defined as: A temporary form representing the base of denture to which occlusion rims are attached. It is used in recording maxilla-mandibular relations and in the arrangement of teeth. Uses: 1. Support of the occlusal rims. 2. Recording maxillomandibular relation. 3. Carry of artificial teeth to perform try in procedure. 4. Gives an idea about the contour, extent and esthetics of the denture. Materials used in the Construction of Record Base:- 1. Shellac record base. 2. Hot curing acrylic resin. 3. Self-curing acrylic resin. 4. Light curing acrylic. Requirements of Record Base:- 1. The record base must have rigidity. 2. The record base must have accuracy and stability. 3. The borders should be developed in the same manner as the borders of the finished denture. 4. All surfaces that contact the lips, cheeks and tongue should be smooth, rounded and polished. 5. The crest and labial and/or buccal slopes should be thin to provide space for tooth arrangement. 6. Biocompatible Occlusion Rims Uses 1. In determination of jaw relation which include:- A. Determination of the vertical dimension. B. Determination of the centric and eccentric jaw relation. 2. In selection of teeth:- A. The position of midline can be determined. B. Canine line (cuspid line) C. Width of 6 anterior teeth is equal to the distance between 2 canine lines. D. Width of posterior teeth is equal to the distance between the canine line and the end of wax rim posteriorly. E. The high length of anterior teeth is determined by drawing high lip line (Gum line, Smiling line). F. The low lip line (Speaking line, relaxed lip line)is a line drawn on wax rim when lip is relax, in this case 2-4mm of anterior teeth should be seen. 3. Setting up of teeth. 4. Orientation of occlusion plane. 5. Determination of shape of the arch. 6. Support of facial musculature. Measurement of Maxillary Occlusion Rim:- 1. The maxillary rim should have a slight labial inclination, and the maxillary labial surface should be 7mm anterior to the line bisecting the incisive papillae. 2. The final wax rims should be 4mm wide anteriorly and gradually become wider posteriorly to measure 7mm. 3. They should be directly over the crest of the residual ridges. 4. The occlusal height of maxillary rim should be 22mm from labial flange lateral to the labial frenum. 5. Its level should be (2-4mm) lower than upper lip at rest. 6. It should touch the vermilion border of the lower lip in pronunciation of letter (f and v). 7. Upper occlusal rim has U shaped. Measurement of Mandibular Occlusion Rims:- 1. It should occupy the space over the crest of the residual ridge. 2. The occlusal height should be 18mm from the labial flange lateral to the labial frenum and should be level with the acrylic base posteriorly. 3. The labio lingual thickness should be approximately 4mm anteriorly and also increase posteriorly to be 7mm in molars area. 4. Its level should be with the lower lip anteriorly and it should be flush to two-third height of the retromolar pad posteriorly. 5. Lower occlusal rim has V shaped. Occlusal Plane it is an imaginary plane related to cranium anatomically and theoretically attaches the incisal edges of incisors and occlusal surface tips of posterior teeth. The average plane established by the incisal and occlusal surfaces of the teeth. Fox Bit (Fox Plane Guide):-it is an appliance used for orientation and determination of the occlusal plane on the bite rims. It consists of: Anterior part Lateral part Inner part The inner part: should be applied on or attached the upper bite rim inside the patient mouth. The anterior part: which represents the anterior part of occlusal plane of upper occlusion rim should be parallel to the interpupillary line of the patient (imaginary line running between right and left pupils of the patient's eyes when the patient is looking straight forward). The lateral part (antero-posterior occlusal plane): which represents the posterior part of occlusal plane should be parallel to ala-tragus line or Camper's line (imaginary line running from the inferior border of the ala of the nose to the superior border of the tragus of the ear). Generally, the basic fabrication of occlusion rims is a laboratory procedure and the final contouring is accomplished at the dental chair by the dentist prior to recording of maxillomandibular relation. Free way space: is the distance between the upper and lower teeth or bit rims when the mandible is in the physiological rest position, it is (2-4mm) observed at first premolar region. Speaking space: is the distance between the upper and lower posterior teeth when the patient pronounced (s) sound, it about is (1.5-3mm) for most patient. It is larger in patient with class II while it is smaller in patient with class III
