Easy way to remember occlusion (contacts)

[DrTacoElf]

Hey guys wondering if there are any shortcuts you can use to remember occlusion MI contacts....

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[JavadiCavity]

Hey guys wondering if there are any shortcuts you can use to remember occlusion MI contacts....

First off, to know which tooth is occluding with tooth X, just subtract tooth X from 33. For example, tooth 27 occludes with tooth 6 (33 -27 = 6).

Not a trick that I have, but I noticed that posterior teeth all follow a pattern in MI:

• Contacts on Maxillary teeth: the mandibular molar's mesial buccal cusp tip occuldes on to the maxillary molar's MESIAL marginal ridge; and the mandibular molar's distal buccal cusp tip occludes into the MESIAL fossa of the maxillary molar.

• Contacts on Mandibular teeth: the maxillary molar's distal lingual cusp tip occuldes on to the mandibular molar's DISTAL marginal ridge; and the maxillary molar's mesial lingual cusp tip occludes into the DISTAL fossa of the mandibular molar.

For premolars, I believe there is only one contact per tooth. And it follows the same pattern. Since there is only one cusp in function, all you need to remember is that maxillary teeth occlude in mandibular DISTAL fossa/marginal ridge, and mandibular teeth occlude in MESIAL fossa/marginal ridge.

 

[ScubaDr2B]

ok, I don't know how to add a picture to a post so I put it as my avatar...I'm not sure how well you can see it but maybe can get the general idea....you can basically draw a fence type picture and the "fence posts" represent the centric holding cusps...it works pretty well, you can just jot it down quickly during a test and if you need class II or III you can just slide the mandibulars backward or forward...maybe you can see the picture ok, if not PM me and I can email you a bigger version...hope that helps, enjoy

 

[PERFECT3435]

First off, to know which tooth is occluding with tooth X, just subtract tooth X from 33. For example, tooth 27 occludes with tooth 6 (33 -27 = 6).

Not a trick that I have, but I noticed that posterior teeth all follow a pattern in MI:

• Contacts on Maxillary teeth: the mandibular molar's mesial buccal cusp tip occuldes on to the maxillary molar's MESIAL marginal ridge; and the mandibular molar's distal buccal cusp tip occludes into the MESIAL fossa of the maxillary molar.

• Contacts on Mandibular teeth: the maxillary molar's distal lingual cusp tip occuldes on to the mandibular molar's DISTAL marginal ridge; and the maxillary molar's mesial lingual cusp tip occludes into the DISTAL fossa of the mandibular molar.

For premolars, I believe there is only one contact per tooth. And it follows the same pattern. Since there is only one cusp in function, all you need to remember is that maxillary teeth occlude in mandibular DISTAL fossa/marginal ridge, and mandibular teeth occlude in MESIAL fossa/marginal ridge.

thank you.

 

[Mach band]

First off, to know which tooth is occluding with tooth X, just subtract tooth X from 33. For example, tooth 27 occludes with tooth 6 (33 -27 = 6).

I thought except the two mandibular central incisors and two maxillary third molars, each tooth occludes with two teeth.

 

[JavadiCavity]

I thought except the two mandibular central incisors and two maxillary third molars, each tooth occludes with two teeth.

Hmmmm....I'm pretty sure that maxillary central incisors quite often occlude with two mandibular incsicors.

As for posterior teeth, each maxillary tooth generally occludes with one mandibular tooth, albeit in multiple locations on that tooth. I wish I could be more clear, but I looked at the diagrams we were given dental anatomy, that's what I'm seeing. I don't think you get overlap between adjacent teeth. But, please, correct me if I'm wrong.

 

[Mach band]

Hmmmm....I'm pretty sure that maxillary central incisors quite often occlude with two mandibular incsicors.

As for posterior teeth, each maxillary tooth generally occludes with one mandibular tooth, albeit in multiple locations on that tooth. I wish I could be more clear, but I looked at the diagrams we were given dental anatomy, that's what I'm seeing. I don't think you get overlap between adjacent teeth. But, please, correct me if I'm wrong.

I'm pretty sure except those four teeth, each tooth occludes with two teeth. If I remember correctly, we had a few questions on this on our first tooth ID practical. This is because the two max central incisors are wider than the mandibular ones, thus, they "push" the rest maxillary teeth posteriorly resulting each tooth centered more in the interproximal area. The maxillary third molars, being the last teeth on the upper arch, occlude with only one tooth which is the mandibular third molar. If you look in the mirror, you'll see what I'm trying to say. Please let me know if I'm wrong. I'm curious about this too.

 

[USUaggie]

Doesn't it depend on if we're in cusp to fossa relationship or cusp to marginal ridge relationship? In cusp to fossa the premolars tripodization happens in a single fossa (making it a one-to-one contact) but in cusp to marginal ridge relationship the tripodization would involve two teeth.

Man, this thread made me think. Occlusion was two quarters ago.

Anyway, the best way I had to get through the occlusion final was to draw out the mandibular cusps and then the maxillary contacts on top of them (maybe in a different color). After two hours of visualizing occlusion my brain was seriously fried.

 

[Mach band]

OK, I found a similar statement in the decks. Under Permanent Tooth section, there is a card for the maxillary third molar, at the end, it states " They occlude only with the mandibular third molars (all other teeth occlude with two teeth except the mandibular central insors.)" I should never doubt the "2th morph" of UCSF!

 

[Typo]

I'm pretty sure except those four teeth, each tooth occludes with two teeth. If I remember correctly, we had a few questions on this on our first tooth ID practical. This is because the two max central incisors are wider than the mandibular ones, thus, they "push" the rest maxillary teeth posteriorly resulting each tooth centered more in the interproximal area. The maxillary third molars, being the last teeth on the upper arch, occlude with only one tooth which is the mandibular third molar. If you look in the mirror, you'll see what I'm trying to say. Please let me know if I'm wrong. I'm curious about this too.

For the boards at least, these are the two rules to burn into your mind:

1. Each maxillary tooth occludes with its counterpart and the tooth immediately distal to it.
2. Each mandibular tooth occludes with its counterpart and the tooth immediately mesial to it.

Exceptions are the mandibular central incisors and the maxillary third molars, which makes sense if you think about it in light of the previous two rules. To see all this occlusion, I'd suggest grabbing a typodont and taking all of the teeth out on one side - this way you can see where each and every cusp occludes lingually as well.

As for special ways to remember what occludes where, there aren't a lot of hard and fast rules that I know of except for pure memorization. Actually, one other helpful rule I can think of is that nothing occludes on any of the marginal ridges of mandibular premolars (the lingual cusps of maxillary premolars have a mesial inclination, so they hit the distal fossae of the mandibular premolars - also, the canine has no lingual cusp so it can't occlude on the mandibular first premolar's marginal ridges).

Stare at your typodonts for hours on end - it'll all become clear (or not). 😛