Missing tooth is it needed to be replaced
Missing tooth replacement is a necessity, especially the anterior, front tooth. But it is equally important in the posterior region also.
It is thought in mind that, Dental arch is statistic entity, but certainly it is not the situation. The maxillary and mandibular teeth are in dynamic equilibrium, where they support each other. When tooth is lost, the structural integrity of the arch is lost and the tooth realigns to the new occclusion. Provided teeth adjacent to it may drift bodily, or even tilt, opposing teeth may erupt into the extraction space.
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Such drifted and supra-erupted tooth can result in food impaction and eventually proximal caries
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And even plaque accumulation and periodontal breakdown and loss of tooth.
Importance of contacts and contours of crown
Contact and contours are an important part of crowns, these contacts and contours act as spill way for food and prevent food passage into sublingual area.
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The contact area proximally on molar tooth is located to the occlusal third, except for the second molar, which is located to middle third. The contact area should be than just a point and is normally an area. The area cervical to contact area should be flat or concave and never should be convex, since that can course gingival inflammation. The proximal contacts are slightty facial to the contour except for the maxillary 1st and 2nd molar which is pretty centralilised. If the contact area is to narrow, it can act as a area of food wedging especially for fibrous foods, and if the contact area is too wide facio-lingually, they do not deflect food from gingival tissues.
The height of contour or the facial surfaces of all posterior tooth occurs in the cervical third and similar in the lingual surfaces of maxillary premolars and maxiillary molars.
On mandibular tooth on the lingual side, this height of contour occur in the middle third.
The amount of lingual curvature varies from 0.5mm on maxillary molars and mandibular 1st premolars and 0.75mm on mandibular 2nd premolars. It is 1mm on mandibular molars. The contours of tooth play on important role because over contouring of tooth can cause food accumulation on cervical area and gingival inflammation.
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Thus the importance of proper contours in crown is mandatory for preventing food impaction and food accumulation and thus promoting good gingival health.