SELECTIVE GRINDING

1. Selective grinding
Dr.shari .S.R

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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

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Armamentarium for Occlusal correction
Paste ,Spray,Paint on material

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Rule of Third
Predict success of selective grinding.

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• 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
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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
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Interferences in the line of closure

8. Mediotrusive contacts Grinding rule: BUCCAL OF UPPER LINGUAL CUSP AND
LINGUAL OF LOWER BUCCAL CUSP (BUL* LLB).
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Eliminating the interferences in balancing side

9. Laterotrusive contacts: LINGUAL OF UPPER BUCCAL CUSP AND BUCCAL OF LOWER
LINGUAL CUSP (LUB* BLL)----Working side interferences
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Eliminating lateral interferences – BULL’s Law

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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

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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:

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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.

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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.

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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.

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Types of balancing side occlusal error and their
correction:- 2
1) 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.