Lecture 07: Occlusal Transfer PDF

OCCLUSAL TRANSFER SARA ZAKY MOHAMED ASSOCIATE PROFESSOR OF YEAR 3 PROSTHODNTICS  INTRODUCTAION an accurate determination, recording and transfer of jaw relation records from patients to the articulator is essential for the dental restoration function, facial appearan...

OCCLUSAL TRANSFER SARA ZAKY MOHAMED ASSOCIATE PROFESSOR OF YEAR 3 PROSTHODNTICS  INTRODUCTAION an accurate determination, recording and transfer of jaw relation records from patients to the articulator is essential for the dental restoration function, facial appearance and maintenance of patient's oral health. During prosthodontic treatment, it is important for both the dentist and the dental technician to construct indirect restorations that are well fitted in patient’s masticatory system in a minimum amount of time and effort 2  Mounting The laboratory procedure of attaching the maxillary or mandibular cast to an articulator or similar tool. The significant of mounting are: 1. To maintain of the vertical dimension of occlusion 2. To keep horizontal centric jaw relation. 3. To ease arrangement of artificial teeth 3  Types of records 1- Static record provides the position of the maxilla in relation to the hinge axis, or rather the ideal axis that joins the two condyles of the mandible. In dentate patients, the facebow fork is used to record the maxillary occlusal surfaces using a variety of different media. 4  Types of records 2- interocclusal record 5  3-Dynamic record 1- stereographic The stereographic articulator allows customized condylar fossa moldings to be prepared individually for each patient 2- pantographic A pantographic tracing is a graphic record of mandibular movement, usually recorded in horizontal, sagittal, and frontal planes, and physically registered by styli tracing on recording tables, or by means of motion-sensitive electronics. 6  scoring By using the plaster knife or by laboratory handpiece with metal round bur to make 3-4 (V) shape cuts on the base of upper and lower casts that used as mounting index to facilitate the remounting after construction final denture. The index cuts should be approximately 1/4 inch in depth and 1/2 inch in width. Then lightly coated the base of the casts and the cuts with Vaseline or any separating medium 7 Scoring of the cast scorin g Scoring f the  Steps for mounting 1. The articulator should be clean. 2. The incisal pin flushed with the upper member of the articulator. 3. the incisal guide table at zero degree. 4. The mounting table properly fixed to the articulator. 5. Determine the midline of the cast. 6. With the wax knife 3 or 4 cuts are made on the base of upper and lower casts. 11  According to type of articulators In case of using mean value articulator (fixed condylar path) should be: 1. Clean from any remnant of previous plaster. 2. The incisal pin positioned (Level) with the top of upper member of articulator to give zero reading. 3- The mounting table properly fixed to the articulator member. 12 13 14  Mounting with face-bow 1. Identify the anterior and posterior reference points for the facebow (e.g., external auditory meatus, orbitale). 2. Prepare the bite fork and occlusion rim. 3. Place the bite fork centered to the arch, indexing it to the teeth with wax or elastomer. 4. Place the facebow over the bite fork rod anteriorly. 5. Place the bow evenly into the ears posteriorly. 6. Secure the bow anteriorly 15  7. Position the bow anteriorly to the third point of reference (establishes the horizontal plane). 8. Secure the bite fork vertical rod, then the horizontal rod (holding the bow securely to prevent torque). 9. Release the bow anteriorly to allow spread and disengage from the ears. 10. Remove the fork downward and out of the mouth with the attached bow. 11. Carefully check the security of the attachments. 16 17 18  After recording the orientation jaw relation, the following steps are carried out: 1. Enough space should be present between the base of the cast and the upper member of the articulator to accommodate for the plaster material over the cast. If there is not enough space trimming should be done to the base of the cast. 2. Alignment of the midline of the maxillary occlusion rim to the center of the cross midline which found on the mounting table anteriorly and posteriorly, so that the cast will be centralized to the mounting table and the occlusal rim fixed to the mounting table by wax. 19 20  Mounting the lower cast The mandibular cast is mounted after recording the vertical and centric jaw relations. 1. The mandibular occlusion rim should be well secured to the mandibular cast with it record base by using wax, also sealing should be done between the maxillary and mandibular rims after making tentative centric jaw relation. 2. Care should be taken that there is no posterior interference between the maxillary and mandibular casts (Heel area). 3. The articulator with the mounted maxillary cast is inverted to aid in the mounting the mandibular cast. 4. The maxillary occlusal rim with mandibular occlusal rim (centric record) placed on the maxillary cast. 21 22  Checking the mounting :- 1. The midline of maxillary cast should be coincided with the midline of mandibular cast and midline of articulator. 2. Centralization of maxillary cast with upper member of articulator then the centralization of lower cast which depend on accuracy of the maxillary cast. 3. Incisal pin checked if it does not touch the incisal table. 4. Healer's area checked if there is any contact between the maxillary and mandibular casts 23 24  Errors might occur during mounting 1. The record base is not properly secured to the cast. 2. Interference of the casts posteriorly. 3. The incisal pin does not touch the incisal table. 4. The incisal pin is not properly screwed. 5. Wrong transference of the midline of the articulator with that of the casts (shifting of the midline). 6. Movement of the casts during mounting. 7. Maxillary and mandibular rims are not properly fixed after making centric record. 8. Dimensional changes in the plaster material. 9. Face-bow record defected 25