20- Jaw relation registration. Part 1: Checking occlusal rims - Orientation of occlusal plane скачать в хорошем качестве

20- Jaw relation registration. Part 1: Checking occlusal rims - Orientation of occlusal plane

• The trial denture base may be made from self-cure acrylic or light-cure acrylic resin. • Shellac base plates are not recommended because of its dimensional inaccuracy. • Occlusal wax rims should be made from high quality base plate wax it must be dimensionally stable inside and outside the patient mouth. • The dimensional stability is must to maintain the vertical and centric relations during and after registration. • Checking of the occlusal rims outside the patient mouth away from the cast & on the cast. • Examination away from the cast. Sharp and irregular borders must be avoided. Fitting surface must be clean from dental stone, wax & sharp areas. • Examination on cast. It must be well adapted to the cast & fill the vestibule in length and width. Review the standard height of wax rims. • Instruments & materials: • wax knife, wide blade wax spatula, flame source, rubber bowl with cold water, Fox ruler, base plate wax, inter-occlusal record material (light rubber base, ZnO, wax) Vaseline, adhesive tape, Fox ruler used for proper orientation of anterior & posterior occlusal plane, Face bow & semi adjustable articulator should be ready for transfer of jaw relation record. • Checking the occlusal rims inside the patient mouth. • Checking extension, retention & stability of occlusal rims. • Checking extension of labial and buccal flanges by manipulating lips and cheeks with gentle pressure to hold the occlusal rim in place by the other hand. • Checking extension of lingual flanges by instructing the patient to move his tongue in movements similar to that of border molding. • Checking retention & stability of lower occlusal rim. • Suction sound ensures that a good retention exist :) • Checking retention & stability of upper occlusal rim. • Wet the trial denture base before insertion into the patient mouth to enhance the physical means of retention. • Checking extension of labial and buccal flanges by manipulating lips and cheeks with gentle pressure to hold the occlusal rim in place by the other hand. • Check stability to occlusal stresses. Occlusal wax rims must be centralized over the alveolar ridge. • Examination of retention for upper occlusal rim. It should resist the vertical displacement away from the tissues. • The high suction sound ensures that excellent retention exist. • Orientation of the occlusal plane: • Contouring of wax rims (Labial & buccal) surface to obtain better lip support before orientation of the occlusal plane. • Over-contouring to mask facial wrinkles makes the lip line higher, affect phonetics& biomechanically not favorable (more denture displacement). • Review proper lip contouring from facial and profile views. • Detection of the height of occlusal plane: Upper (maxillary) & lower (mandibular) - Anterior & Posterior. • Maxillary occlusal plane: • Maxillary anterior occlusal plane: • Esthetics: 2 mm below relaxed normal lip line. • Phonetics: instruct the patient to say F or V sound. The occlusal surface of upper occlusal rim touches the superior surface of lower lip. • Anatomical: Anterior occlusal plane must be parallel to Inter-pupillary line. • Maxillary posterior occlusal plane: • Parallel to Ala-Tragus line - At Linea Alba - Just 3/4 inch below Stenson's duct. • Fox ruler is a very efficient tool to ensure parallelism of occlusal planes to the anatomical lines. • If the occlusal plane is not parallel modify the wax occlusal surface inclination until you achieve the required parallelism. • Mandibular anterior occlusal plane • Flushed with superior surface of lower lip and ended by angle of the mouth. • Parallel to inter-pupillary line & maxillary anterior occlusal plane. • Mandibular posterior occlusal plane • Functional & Biomechanical: height not more than 3/4 retromolar pad area. • Functional & Biomechanical: Just below the maximal convexity of the tongue. • Neutral zone impression: Located at the Buccinator groove. • Anatomical: It should be parallel to the mean of both ridges. • The Guide Lines: Midline - Canine Line - relaxed lip line - active lip line - orientation lines. • The canine line is highly significant to detect the width of missing anterior teeth. • The orientation of relaxed and active smile lines used to detect the proper length of missing anterior teeth (Making an ideal smile).