Tuesday, July 30, 2013
Incisal guidance
Discuss the factors for which the incisal guidance adjustment is used when setting teeth up for complete dentures in balanced occlusion. Also how/in which way this influences the anterior tooth arrangement and the choice of posterior teeth. Each student to comment in their own words and do not repeat or copy someone elses comments.
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Incisal guidance is the effect the maxilla and mandibular anterior teeth have when they contact whilst the mandible is in motion. The incisal guidance plays a important role in balanced occlusion because if the incisal guidance is steep ,it will therefore reqire steep cusps, steep occlusal plane and a steep compensating curve in order for it to be able to effect the occlusal plane.
ReplyDeleteFACTORS;
ReplyDelete1. Vertical overlap (over bite): the vertical overlap is directly proportional with the incisal angle. For complete dentures the incisal guidance should be as flat as esthetic and phonetics will permit. The incisal guidance is reduce by:
-Setting the upper anterior teeth outside the ridge
-Setting the lower anterior teeth inside the ridge without encroaching on the tongue space
-Shorten the upper and lower anterior, if esthetics and phonetics allows.
2. Plane of Occlusion – the occlusal plane is established in the anterior by the height of the lower canine and by the height of the retromolar pad.
3. compensating curve- A lesser compensating curve for the same condylar guidance will result in a steeper incisal guidance (anterior interference), which will cause loss of molar contacts during balancing.
This can be described as the contact of the maxillary and mandibular anterior teeth and the effect that they have on the movement of the mandible. the incisal guidance can be expressed by a line drawn horizontally in centric occlusion between the incisal edges of the maxillary and mandibular teeth. The closeness to the occluding tooth surfaces of the teeth posterior to it, the incisal guidance plays an important role in the way the posterior teeth contact. In other words, posterior teeth with require steep cusps, steep occlusal plane or steep compensating curve all result from a steep incisal guidance. This makes the incisal guidance extremely important to the symmetry and steadiness of the denture. However where complete dentures are concerned the incisal guidance is preferred to be as flat as aesthetics and phonetics will allow. When arranging the anterior teeth with a vertical overlap it is necessary to set a compensating horizontal overlap in order to prevent governing incisal guidance from ruining the occlusal balance of the denture.
ReplyDeleteIncisal guidance is called the second factor of occlusion and sometimes referred to as the anterior guidance. It also acts as a controlling path for the movement of the casts in an articulator. It is the effect the contact of the upper and lower anterior teeth have on the movement of the mandible. This guidance is largely dependent on the horizontal and vertical overlap (overjet and overbite) and has a dominant influence on the contacting surfaces of posterior teeth. Steep incisal guidance requires posterior teeth with steep cusps, a steep occlusal plane and a steep compensation curve in order to achieve an occlusal balance.The occlusion of teeth in a case of steep incisal guidance will determine the equilibrium and stability of the denture.
ReplyDeleteIncisal guidance refers to the angle at which the anterior teeth "slide" over each other during excursions of the mandible. This involves the amount of ovejet and overbite in the anterior region. The cusp anlgles of the posterior teeth will dictate the incisal guidance, or vica versa - monoplane posterior teeth will require the anteriors to be set up with minimal/no overjet/overbite while anatomical teeth will require more overbite/overjet.
ReplyDeleteThe incisal guidance can be described as the guideline of occlusion for the maxillary and the mandibular anterior teeth. It is basically the mean value of the interalveolar distance recorded, this we read from the record blocks. It assists in determining the plane of occlusion and the alignment and occlusion of the posterior teeth.
ReplyDeleteThe incisal height is followed and used to place the posterior teeth aswell.
ReplyDeleteThe incisal guidance is between the overbite (vertical overlap) and the overjet (horizontal overlap).
ReplyDeleteThe incisal guidance or anterior guidance is the effect the contact of the maxillary and mandibular anterior teeth has on the movement of the mandible. In complete dentures the incisal guidance has a great effect on the path of movement of the teeth during lateral and protrusive movements and is a useful factor in producing balanced occlusion.
ReplyDeleteInfluencing factors include:
ReplyDelete(1) esthetics,
(2) phonetics,
(3) ridge relations,
(4) arch shape,
(5) interridge space.
Esthetics and phonetics are the primary factors limiting the dentist’s control of incisal guidance. Esthetic and phonetic requirements necessitating a high incisal guide angle are considered to be criteria for selection of cusped teeth and a balanced occlusion.
The ideal setting would be to set the incisal guide table as nearly parallel to the occlusal plane as possible, thus creating a small incisal guide angle and low cusp angulation. All other factors being equal, a large incisal guidance requires steep cusp angulation to maintain balance, a condition which is thought to detract from denture stability.
The incisal guide angle can be lowered by decreasing the vertical overlap or increasing the horizontal overlap of the anterior teeth.
Well done to all those who commented
ReplyDeleteFurther studies have demonstrated that there is also a good harmony between TMJ guidance elements along with anterior guidance
ReplyDeleteSo it's a relation between TMJ anatomy , cusp morphology of posterior teeth and anterior guidance of anterior teeth
Beside at British dental Journals series they once referred to anterior guidance all the elements that's located anterior to TMJ , in other words not only anterior teeth but also posterior teeth to be considered , all teeth ( not only anterior teeth )to be considered elements of anterior guidance