Selective grinding

SELECTIVE GRINDING

1. Selective grinding Dr.shari .S.R

2. 2 Occlusal Equilibration It is a procedure by which the occlusal surfaces of the teeth are precisely altered to improve the overall contact pattern. Procedure includes: Reduction of all contacting teeth surfaces that interfere with the terminal hinge axis closure. Selective grinding of tooth structures that interfere with lateral excursion. Selective grinding of teeth that interferes with protrusive movement. Harmonization of anterior guidance

3. 3 Armamentarium for Occlusal correction Paste , Spray,Paint on material

4. 4 Rule of Third Predict success of selective grinding.

5. 5 INTERFERENCES IN THE ARC OF CLOSURE —Anterior slide INTERFERENCES IN THE LINE OF CLOSURE- ---Right or left slide (Dawson) According to Okeson CR slide can be 3 types : Anterosuperior Antereosuperior and to the right Antereosuperior and to the left Eliminating interferences to centric relation position

6. Due to contact between mesial inclines of maxillary cusps and the distal inclines of the mandibular cusps Grinding rule MUDL 6 Interferences in the arc of closure

7. Slide toward cheek: Due to inner incline of the maxillary lingual cusp against the inner incline of the mandibular buccal cusp. Grinding rule: BULL Slide toward tongue : Due to lingual incline of the upper or buccal incline of lower. Grinding rule: LUBL 7 Interferences in the line of closure

8. Mediotrusive contacts Grinding rule : B UCCAL OF U PPER L INGUAL CUSP AND L INGUAL OF L OWER B UCCAL CUSP ( BUL* LLB ). 8 Eliminating the interferences in balancing side

9. Laterotrusive contacts : L INGUAL OF U PPER B UCCAL CUSP AND B UCCAL OF L OWER L INGUAL CUSP ( LUB* BLL )----Working side interferences 9 Eliminating lateral interferences – BULL’s Law

10. 10 GRINDING BASIC RULES: Narrow stamp cusps before reshaping fossae. Don’t shorten a stamp cusp. Upper teeth are always adjusted on the inclines that face the same direction as the slide. Lower teeth are adjusted by grinding the inclines that face the opposite direction from path of the slide. Adjust centric interferences first Then lateral excursive interferences Protrusive interferences . It can occur between distal inclines of maxillary lingual cusp and mesial inclines of mandibular buccal cusp. Grinding rules: DUML Eliminating interferences in Protrusive contacts

11. 11 Occlusal equilibration in complete denture Incorrect registration of RCP Irregularities in setting the teeth Tooth movement during deflasking and packing. Incomplete flask closure. Causes of occlusal disharmony:

12. 12 Types of occlusal error in centric occlusion and their correction.: 3 1 )Any pair of opposing teeth can be too long and hold the other teeth out of contact. Correction: The fossae of the teeth are deepened by grinding so the teeth will in effect,telescope into each other.The cusp are not shortened. 2)The upper and lower teeth can be too nearly end to end. Correction: Grind the outer inclines of the functional cusp. 3) The upper teeth can be too far buccally in relation to lower teeth. Correction: Grind the inner incline of the functional cusp from fossae.so broadening the fossae near the inner incline.

13. 13 Types of working side occlusal error and their correction:- 6 1) Both the upper buccal cusp and the lower lingual cusp are too long . Correction: The length of cusps are reduced by grinding to change the incline extending from the central fossae to the cusp tip.,Central fossae is not made deeper,but the cusps made shorter. 2) The buccal cusp make contact but the lingual cusp donot . Correction : Buccal cusp of the upper teeth are ground from the central fossa to the cusp tip to shorten the cusp. 3) The lingual cusp make contact but the buccal cusp donot . Correction: The lower lingual cusps are shortened by changing the buccal incline of the lower lingual cusp ,so it is not as steep.

14. 14 Types of working side occlusal error and their correction:- 6 4) Upper buccal or lingual cusps are mesial to their intercuspative postions Correction: Grinding is done on the mesial inclines of the upper buccal cusps and distal inclines of the lower cusps. 5)Upper buccal or lingual cusps are distal to their intercusping positions. Correction : Grinding is done from the distal of the upper cusps and from the mesial of the lower cusps. 6 ) Teeth on the working side may not contact . Due to excessive contact on balancing side. Correction: Grind lingual incline of the lower buccal cusp.

15. 15 Types of balancing side occlusal error and their correction:- 2 Balancing side contact is so heavy so that working side teeth are held out of contact. Correction: Grind the lingual incline of the lower buccal cusp. 2) There is no contact on the balancing side: Correction : Grind lingual incline of the upper buccal cusps and buccal incline of lower lingual cusp .