We proceed the occlusion theme on this month’s Prosthodontips because the Josh Sharpling and Zo Ali focus on static and dynamic occlusion.
Within the February column, we went again to the fundamentals of occlusion. Have a fast look by that because the gadgets mentioned are actually the elemental constructing blocks of occlusion.
The purpose of those columns is to provide you a working data of occlusion and to maneuver away from overly difficult or dogmatic approaches.
Therefore, I’ll preserve issues as easy and relatable to on a regular basis observe as potential.
Now that you’ve an understanding of the important thing phrases, we’re going to have a look at a bit extra intently on the options of static and dynamic occlusion.
Earlier than doing that, it is very important perceive when all of this data is definitely vital to gather and file.
While it’s nearly at all times related in some form or type, it’s usually not extraordinarily vital when finishing up single tooth dentistry. In these conditions, it’s usually potential to easily determine the occlusal contacts for that one tooth and guarantee we respect these limitations when restoring. It’s because the adjoining tooth present reference factors and assist to guard the brand new restoration/tooth.
Nevertheless, let’s assume that we’re practising quadrant dentistry and restoring a number of posterior tooth in a single quadrant in a single go to.
That is fairly a typical incidence and in these conditions, it’s a lot simpler to lose occlusal management. It’s because we’re basically resetting the occlusion on that aspect.
Once we restore all these posterior tooth in a single go to, we lose these very important reference factors. It turns into way more vital to reintroduce them in a predictable method.
The column this month is meant as a sensible information. It is rather easy and the purpose is to offer you primary checks you should use on nearly each affected person.
Nevertheless, it’s not an exhaustive occlusal evaluation. Sure circumstances would require higher diligence. As at all times, do get in contact when you’ve got any burning questions or particular queries!
This merely refers back to the options of occlusion when the mandible is in ICP, ie maximally interdigitating.
While there aren’t any black and white guidelines relating to precisely what wants recording, I make notice of the next key options which might be related to each day observe:
- Incisor classification (British Standing Incisor Classificaton, BSI)
- Class I
- decrease incisor edges occlude on or lie beneath the cingulum plateau of the higher incisors
- Class II
- Decrease incisor edges occlude behind the cingulum plateau of the higher incisors
- Division one: the higher incisors are proclined
- Division two: the higher incisors are retroclined.
- Class III
- Decrease incisor edges occlude anterior to the cingulum plateau of the higher incisors
- Class I
- Overbite and overjet
- This provides extra data on prime what we now have already learnt from the incisor classification
- If there’s elevated overjet, then we all know instantly that the mandible might should journey additional earlier than the anterior tooth interact and create house between the posteriors. Therefore, we might have to be cautious when restoring posterior tooth
- A diminished overbite would end in related issues, only for a special motive. On this state of affairs, there’s little or no guiding floor obtainable. Though the chew might open instantly as soon as the mandible is transferring, the quantity of house between the posteriors could also be very restricted. Successfully we see the identical downside as with elevated overjet and posterior tooth could also be clashing unfavourably (interferences)
- Be aware that clashing posterior tooth are usually not at all times an issue and pure. Unrestored tooth might final a lifetime with none points. Nevertheless, giant restorations and so on considerably weaken tooth and subsequently it turns into extra vital to plan appropriately
- In essence, understanding overbite and overjet offers tells us in regards to the potential for anterior steering throughout dynamic actions. Overbite and overjet inform us how shut the anterior tooth are to one another and subsequently how efficient they are going to be in guiding the mandible
- ICP contacts
- Merely ask the affected person to chew collectively and mark these with skinny articulating paper. Verify every mark with shim inventory and file which tooth maintain the shim inventory when the affected person is biting collectively (Determine 1)
- This tells what number of occluding pairs of tooth there are on both sides
- It’s also useful when checking occlusion after finishing a restoration as we will verify the presence of the identical pre-op shim inventory holds.
Merely put, which tooth are in touch when the mandible is transferring ahead, left and proper. Utilizing two totally different colored articulating papers is the simplest solution to file this.
For instance, with blue articulating paper, ask the affected person to chew collectively and perform protrusive actions. Then ask the affected person to chew collectively into ICP, however this time with pink articulating paper. While you look at the marks left behind, blue marks with no pink are the guiding surfaces and you may file these because the guiding tooth throughout protrusive actions. Repeat this for left and proper actions.
Typically it’s even simpler and there’s no want to make use of articulating paper. Utilizing a dental mirror, it’s simple to really visualise which tooth are guiding the mandible because it strikes away from ICP.
Normally, the maxillary incisor tooth are inclined to information protrusion.
Lateral actions are often both canine guided or in group operate.
Canine steering is self-explanatory. Group operate is the place there are a number of tooth sharing the occlusal load because the mandible strikes let or proper.
Typically the steering begins in group operate however ends solely on the canines, or vice versa. Don’t let this confuse you or permit your self to over complicate issues. Simply file what you see.
If you find yourself doing a restoration, normally, you’ll merely be trying to reproduce what was there beforehand. Circumstances the place you would possibly need to change it embody closely restored and root canal handled tooth, or the place extra delicate restorations (eg veneers) are being positioned.
I hope you loved this month’s column, and, as at all times, please get in touch when you’ve got any questions.
If there are particular subjects you want to us to cowl in a column, please tell us.