Hello everyone!!
Occlusion is the core of any dental treatment. Proper execution of concepts of occlusion doesn't just provide best results but also give longevity to the prosthesis resulting healthy periodontium and TMJ.
Today, we will discuss different concepts of occlusion focusing mainly on Canine Guided and Group Function occlusion.
But, before that, let's freshen up our basic understanding of the Balanced Occlusion.
Balanced Occlusion is defined as the bilateral, simultaneous, anterior, and posterior occlusal contact of teeth in centric and eccentric positions.
What does that mean? Let's understand by the example. Balanced occlusion is given in Complete denture.
Suppose, this is our complete dentures in centric occlusion. Remember, centric occlusion and maximum intercuspation is same in case of Complete Denture.
In centric occlusion, all the posterior teeth are in the occlusion and there is overjet and overbite in the anterior teeth.
In coronal or Frontal view, all the posterior teeth are in contact. So, there is balance in the denture and no rocking of any denture. Our denture is stable.
Now, let's see what happens in protrusion.
In protrusion, as soon as anteriors comes edge to edge, posterior teeth cups comes in contact and this way, again thare is contact at all the points and Denture is stable. There is no rocking in anterior or posterior region.
Suppose, we move our mandible to the left, then in coronal section again, all the posterior teeth are in the contact making the denture balance.
So, the definition itself is the explanation i.e., Balanced Occlusion is the bilateral, simultaneous, anterior, and posterior occlusal contact of teeth in centric and eccentric positions.
If there is disoccluion at any point, there will be loss of stability and rocking of the Denture.
Now, let's understand another occlusal scheme i.e. mutually protected occlusion.
Our mandible is class 3 lever, that means force nearer to the muscles will be more.
So, posteriors will bear more force than anteriors during biting. That's why they can be used to crush the hard food.
Plus studies have shown that, contact in posterior will increase masseter and temporalis activities.
Now, suppose you bite an apple from anterior teeth. At this moment, we don't need posterior teeth contacting.
Because 1. They will be unnecessarily overload and 2. Muscle will be unnecessarily activated leading to fatigue.
This type of scheme where the anterior teeth protect the posterior teeth in eccentric movements and conversely have the posterior teeth protect the anterior teeth in maximal intercuspation without any deflective occlusal contacts or interferences in speech is called as mutually protected articulation.
But, what if you have a harder food like a raw meat. Then you need to tear it with Canines.
In this case, only Canines of the working side will be contacting teeth in the mouth. All the other teeth will be disoccluded. This type of scheme where canine prevents all the other teeth from contacting is called as Canine Guided Occlusion or Organic Occlusion, which a part of mutually protected occlusion. As canines have longer roots, the can withstand higher forces and they nearer to muscle compared to incisors, they can produce more forces.
But what if, canines are either periodontally compromised or they are worn off?
In that condition, along with Canines, other posterior teeth on working may also contact. This is called group function occlusion.
The Glossary of Prosthodontic Terms defines Group function as multiple contact relations between maxillary and mandibular teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces. The group function of the teeth on the working side distributes the occlusal load. The obvious advantage is maintenance of the occlusion. The group function philosophy appears to be one of the physiologic wear. Several authors have suggested that occlusal wear is a natural, beneficial and inevitable in a well‑developed dentition.
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12 фев 2024
