Tooth Arrangement (Posterior) PDF

Tooth Arrangement (Posterior) Dr. Malak Bamigdad BDS KAU, Saudi Board in Prosthodontic dentistry  General Considerations for the Arrangement of the posterior Teeth  Mandibular Posterior Tooth Arrangement  Maxillary Posterior Tooth Arrangement Teeth Arrangement Order Gen...

Tooth Arrangement (Posterior) Dr. Malak Bamigdad BDS KAU, Saudi Board in Prosthodontic dentistry  General Considerations for the Arrangement of the posterior Teeth  Mandibular Posterior Tooth Arrangement  Maxillary Posterior Tooth Arrangement Teeth Arrangement Order General Considerations for the Arrangement of the Posterior Teeth 1. vertical overlap of the anterior teeth is occasionally indicated due to the esthetic, phonetic, or functional demands of the patient. General Considerations for the Arrangement of the Posterior Teeth 2. No Teeth on a slop (the retromolar pad) In case of Insufficient anteroposterior space for all four posterior teeth,(1st premolar or 2nd molar) is eliminated Eliminate 1st premolar for better chewing  3. Nonbalanced occlusion, the mandibular posterior teeth are arranged on a flat occlusal plane with the long axes of the posterior teeth arranged perpendicular to the plane of occlusion For balance occlusion, posterior teeth arranged in compensating curve  The central grooves and centers of the marginal ridges of the teeth should lie in one continuous line, which may be straight or have a slight curvature with the concavity being directed lingually or palatally Lingualized Occlusion Factors Affecting Balanced Occlusion 1. Condylar guidance 2. Compensating curve 3. Incisal guidance 4. Cuspal inclination 5. Plane of occlusion Mandibular Posterior Tooth Arrangement The distal surfaces of the canines are the most anterior position for placement of the first premolars. The distal limit to placement of mandibular molars is the beginning of the incline of the retromolar pad The premolars should be arranged so that the buccal surface of the first premolar aligns with the buccal surface of the canine. In achieving this relationship, the central groove of the first premolar should align with either the contact point between the canine and lateral incisor or the tip of the canine  Posteriorly the mandibular molars, particularly the second molar, should be positioned almost directly over the remaining residual ridges A line can be drawn along the crest of the mandibular residual ridges till the land area. A guideline can now be visualized connecting the anterior (canine) to posterior (crest of ridge) guides. The correct alignment of the premolars and molars is indicated when the central grooves are centered on this line and all central grooves align with each other Posteriorly, the plane of occlusion is generally placed at the level of the middle to upper one-third of the retromolar pad and ideally is located midway between the maxillary and mandibular residual ridges and parallel to both ridges  When alteration of the vertical height of the occlusal plane become necessary, generally because of a lack of interocclusal clearance, the plane should be lowered whenever possible. Lowering the plane will decrease the height of the denture teeth above the mandibular residual ridges, decrease cantilever forces, and increase the stability of the mandibular denture.  Maxillary Posterior Teeth For a lingualized occlusion, either balanced on nonbalanced, the maxillary posterior teeth are arranged so that the buccal cusps of the opposing teeth are approximately 0.5 mm above the antagonist teeth when the articulator is moved into the working position  For a conventional balanced occlusion, When correctly arranged there is: (1) minimal spacing between the opposing occlusal surfaces in centric occlusion, (2) anterior and bilateral cross-arch contact in all excursive movements, and cross-tooth contact on the working side The maxillary posterior teeth, especially second molars, must be arranged to provide adequate buccal overlap to minimize cheek biting Ideally the lingual cusps of the maxillary teeth are centered on the central grooves and marginal ridges of the mandibular teeth ( the buccal surfaces of the maxillary teeth to be more buccally positioned than the buccal surfaces of the mandibular teeth)  When the natural teeth have been extracted, the mandibular ridge resorbs downward and outward while the maxillary ridge resorbs upward and inward. Because of these resorptive patterns, it may be necessary to create a reverse articulation (crossbite) for the posterior teeth. The reverse articulation (crossbite) Only in the second molar area, while a normal alignment exists in the first premolar area called (a partial reverse articulation) (crossbite) A balanced occlusion will have both bilateral contacts of the posterior teeth and simultaneous anterior contacts in all excursive movements. Thank You